Showing papers in "Journal of Bone and Joint Surgery, American Volume in 1998"

Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation.

Abstract: The degeneration of articular cartilage as part of the clinical syndrome of osteoarthritis is one of the most common causes of pain and disability in middle-aged and older people. The strong correlation between increasing age and the prevalence of osteoarthritis, and recent evidence of important age-related changes in the function of chondrocytes, suggest that age-related changes in articular cartilage can contribute to the development and progression of osteoarthritis. Although the mechanisms responsible for osteoarthritis remain poorly understood lifelong moderate use of normal joints does not increase the risk. Thus, the degeneration of normal articular cartilage is not simply the result of aging and mechanical wear. However, high-impact and torsional loads may increase the risk of degeneration of normal joints, and individuals who have an abnormal joint anatomy, joint instability, disturbances of joint or muscle innervation, or inadequate muscle strength or endurance probably have a greater risk of degenerative joint disease. Recent work has shown the potential for the restoration of an articular surface. Currently, surgeons frequently debride joints and penetrate subchondral bone as well as perform osteotomies, with the intent of decreasing symptoms and restoring or maintaining a functional articular surface. The results of these procedures vary considerably among patients. Clinical and experimental work has shown the important influence of loading and motion on the healing of articular cartilage and joints. Experimental studies have revealed that transplantation of chondrocytes and mesenchymal stem cells; use of periosteal and perichondrial grafts, synthetic matrices, and growth factors: and other methods have the potential to stimulate the formation of a new articular surface. The long-term follow-up of small series of patients has shown that the transplantation of osteochondral autologous grafts and allografts can be effective for the treatment of focal defects of articular cartilage in selected patients. Thus far, none of these methods has been shown to predictably restore a durable articular surface to an osteoarthritic joint, and it is unlikely that any one of them will be uniformly successful. Rather, the available clinical and experimental evidence indicates that future optimum methods for the restoration of articular surfaces will begin with a detailed analysis of the structural and functional abnormalities of the involved joint and the patient's expectations for future use of the joint. On the basis of this analysis, the surgeon will develop a treatment plan that potentially combines correction of mechanical abnormalities (including malalignment, instability, and intra-articular causes of mechanical dysfunction), debridement that may or may not include hunted penetration of subchondral bone, and applications of growth factors of implants that may consist of a synthetic matrix that incorporates cells or growth factors or use of transplants followed by a postoperative course of controlled loading and motion.

Articular cartilage: tissue design and chondrocyte-matrix interactions.

Abstract: The unique biologic and mechanical properties of articular cartilage depend on the design of the tissue and the interactions between the chondrocytes and the matrix that maintain the tissue. Chondrocytes form the macromolecular framework of the tissue matrix from three classes of molecules: collagens, proteoglycans, and noncollagenous proteins. Type II, IX, and XI collagens form a fibrillar meshwork that gives the tissue as form and tensile stiffness and strength. Type VI collagen forms part of the matrix immediately surrounding the chondrocytes and may help the chondrocytes to attach to the macromolecular framework of the matrix. Large aggregating proteoglycans (aggrecans) give the tissue its stiffness to compression and its resilience and contribute to its durability. Small proteoglycans, including decorin, biglycan, and fibromodulin, bind to other matrix macromolecules and thereby help to stabilize the matrix. They may also influence the function of the chondrocytes and bind growth factors. Anchorin CII, a noncollagenous protein, appears to help to anchor chondrocytes to the matrix. Cartilage oligomeric protein may have value as a marker of turnover and degeneration of cartilage, and other noncollagenous proteins, including tenascin and fibronectin, can influence interactions between the chondrocytes and the matrix. The matrix protects the cells from injury due to normal use of the joint, determines the types and concentrations of molecules that reach the tells and helps to maintain the chondrocyte phenotype. Throughout life, the tissue undergoes continual internal remodeling as the cells replace matrix macromolecules lost through degradation. The available evidence indicates that normal matrix turnover depends on the ability of chondrocytes to detect alterations in the macromolecular composition and organization of the matrix, including the presence of degraded molecules, and to respond by synthesizing appropriate types and amounts of new molecules. In addition, the matrix acts as a signal transducer for the cells. Loading of the tissue due to use of the joint creates mechanical, electrical, and physicochemical signals that help to direct the synthetic and degradative activity of chondrocytes. A prolonged severe decrease in the use of the joint leads to alterations in the composition of the matrix and eventually to loss of tissue structure and mechanical properties, whereas use of the joint stimulates the synthetic activity of chondrocytes and possibly the internal tissue remodeling Aging leads to alterations in the composition of the matrix and the activity of the chondrocytes, including the ability of the cells to respond to a variety of stimuli such as growth factors. These alterations may increase the probability of degeneration of the cartilage.

The effect of implants loaded with autologous mesenchymal stem cells on the healing of canine segmental bone defects

Abstract: Bone marrow has been shown to contain a population of rare mesenchymal stem cells that are capable of forming bone, cartilage, and other connective tissues. We examined the effect of cultured autologous mesenchymal stem cells on the healing of critical-sized (twenty-one-millimeter-long) segmental defects in the femora of adult female dogs. Autologous mesenchymal stem cells were isolated from bone marrow, grown in culture, and loaded onto porous ceramic cylinders consisting of hydroxyapatite (65 per cent) and beta-tricalcium phosphate ceramic (35 per cent). The animals were randomly assigned to one of three groups. In Group A (six dogs), a porous ceramic cylinder that had been loaded with autologous mesenchymal stem cells was implanted in the defect. In Group B (six dogs), a ceramic cylinder that had not been loaded with cells was placed in the defect. In Group C (three dogs), the defect was left untreated (no ceramic cylinder was implanted). Radiographs were made immediately after the operation and at four-week intervals. At sixteen weeks, the animals were killed, the involved femora were removed, and undecalcified histological sections from the defects and adjacent bone were prepared. Histological and histomorphometric studies were carried out to examine the healing of the defects and the formation of bone in and around the ceramic implants. Atrophic non-union occurred in all of the femora that had untreated defects, and only a small amount of trabecular bone formed at the cut ends of the cortex of the host bone in this group. In contrast, radiographic union was established rapidly at the interface between the host bone and the implants that had been loaded with mesenchymal stem cells. Numerous fractures, which became more pronounced with time, developed in the implants that had not been loaded with cells. Histological and morphometric analyses demonstrated that both woven and lamellar bone had filled the pores of the implants that had been loaded with mesenchymal stem cells; the amount of bone was significantly greater (p < 0.05) than that found in the pores of the implants that had not been loaded with cells. In addition, a large collar of bone (mean maximum thickness, 3.14 millimeters) formed around the implants that had been loaded with cells; this collar became integrated and contiguous with callus that formed in the region of the periosteum of the host bone. The collar of bone remodeled during the sixteen-week period of study, resulting in a size and shape that were comparable with those of the segment of bone that had been resected. Callus did not develop around the cortex of the host bone or around the defect in any of the specimens in the other two groups.

Corrosion of metal orthopaedic implants.

Abstract: In situ degradation of metal-alloy implants is undesirable for two reasons: the degradation process may decrease the structural integrity of the implant, and the release of degradation products may elicit an adverse biological reaction in the host Degradation may result from electrochemical dissolution phenomena, wear, or a synergistic combination of the two Electrochemical processes may include generalized corrosion, uniformly affecting the entire surface of the implant, and localized corrosion, affecting either regions of the device that are shielded from the tissue fluids (crevice corrosion) or seemingly random sites on the surface (pitting corrosion) Electrochemical and mechanical processes (for example, stress corrosion cracking, corrosion fatigue, and fretting corrosion) may interact, causing premature structural failure and accelerated release of metal particles and ions The clinical importance of degradation of metal implants is evidenced by particulate corrosion and wear products in tissue surrounding the implant, which may ultimately result in a cascade of events leading to periprosthetic bone loss Furthermore, many authors have reported increased concentrations of local and systemic trace metal in association with metal implants1,4,5,9-11,14,18,25,26,28,29,47,49-55,58,71,72,75-77,87,90,108-110 There also is a low but finite prevalence of corrosion-related fracture of the implant This review focuses on electrochemical corrosion phenomena in alloys used for orthopaedic implants A summary of basic electrochemistry is followed by a discussion of retrieval studies of the response of the implant to the host environment and the response of local tissue to implant corrosion products The systemic implications of the release of metal particles also are presented Finally, future directions in biomaterials research and development …

The Chondrogenic Potential of Human Bone-Marrow-Derived Mesenchymal Progenitor Cells*

Abstract: Mesenchymal progenitor cells provide a source of cells for the repair of musculoskeletal tissue. However, in vitro models are needed to study the mechanisms of differentiation of progenitor cells. This study demonstrated the successful induction of in vitro chondrogenesis with human bone-marrow-derived osteochondral progenitor cells in a reliable and reproducible culture system. Human bone marrow was removed and fractionated, and adherent cell cultures were established. The cells were then passaged into an aggregate culture system in a serum-free medium. Initially, the cell aggregates contained type-I collagen and neither type-II nor type-X collagen was detected. Type-II collagen was typically detected in the matrix by the fifth day, with the immunoreactivity localized in the region of metachromatic staining. By the fourteenth day, type-II and type-X collagen were detected throughout the cell aggregates, except for an outer region of flattened, perichondrial-like cells in a matrix rich in type-I collagen. Aggrecan and link protein were detected in extracts of the cell aggregates, providing evidence that large aggregating proteoglycans of the type found in cartilaginous tissues had been synthesized by the newly differentiating chondrocytic cells; the small proteoglycans, biglycan and decorin, were also detected in extracts. Immunohistochemical staining with antibodies specific for chondroitin 4-sulfate and keratan sulfate demonstrated a uniform distribution of proteoglycans throughout the extracellular matrix of the cell aggregates. When the bone-marrow-derived cell preparations were passaged in monolayer culture as many as twenty times, with cells allowed to grow to confluence at each passage, the chondrogenic potential of the cells was maintained after each passage. CLINICAL RELEVANCE: Chondrogenesis of progenitor cells is the foundation for the in vivo repair of fractures and damaged articular cartilage. In vitro chondrogenesis of human bone-marrow-derived osteochondral progenitor cells should provide a useful model for studying this cellular differentiation. Furthermore, the maintenance of chondrogenic potential after greater than a billion-fold expansion provides evidence for the clinical utility of these cells in the repair of bone and cartilage.

Long-Term Results of the Latarjet Procedure for the Treatment of Anterior Instability of the Shoulder*

Abstract: We performed ninety-five consecutive Latarjet procedures for the treatment of recurrent anterior instability of the shoulder between 1969 and 1983. In 1993, we retrospectively reviewed the clinical and radiographic results that were available for fifty-six patients (fifty-eight shoulders) who had been followed for an average of 14.3 years (range, ten to twenty-three years). The purpose of the study was to determine the prevalence of glenohumeral osteoarthrosis and the factors related to its development after the Latarjet procedure. The procedure was performed for the treatment of recurrent anterior dislocation in fifty shoulders and painful recurrent anterior subluxation in eight. All patients had a radiographic evaluation (three anteroposterior radiographs, with the humerus in external, neutral, and internal rotation, and one lateral radiograph) before the operation and at the latest follow-up examination. At the time of the latest follow-up, none of the patients had recurrent dislocation, six patients had apprehension with regard to possible dislocation, and one had occasional subluxation. According to the system of Rowe et al., fifty-one (88 per cent) of the fifty-eight shoulders had an excellent or good result; five (9 per cent), a fair result; and two (3 per cent), a poor result. Twenty-two shoulders had no glenohumeral osteoarthrosis. Thirty-four shoulders had centered glenohumeral osteoarthrosis (the humeral head remained in front of the center of the glenoid cavity), which was grade 1 in twenty-five shoulders, grade 2 in four, grade 3 in three, and grade 4 in two, and two shoulders had grade-4 eccentric glenohumeral osteoarthrosis (the humeral head was more proximal than normal in relation to the center of the glenoid cavity). Postoperative grade-1 glenohumeral osteoarthrosis, unlike the higher grades, had no effect on the function of the shoulder.

Health-Related Quality of Life after Knee Replacement. Results of the Knee Replacement Patient Outcomes Research Team Study*

Abstract: A cross-sectional, community-based survey of a random sample of 1750 of 242,311 Medicare recipients was performed. The patients were at least sixty-five years old and had had a primary or revision knee replacement (either unilaterally or bilaterally) between 1985 and 1989. Three samples were surveyed separately: a national sample (to reflect the United States as a whole) and samples from Indiana and the western part of Pennsylvania (sites chosen for convenience to assess the validity of the findings for the national sample on a regional level). Each sample was stratified by race, age, residence (urban or rural), and the year of the procedure. Valid and reliable questionnaires were used to elicit the participants' assessments of pain, physical function, and satisfaction two to seven years after the knee replacement. Of the 1486 patients who were eligible for inclusion in the survey, 1193 (80.3 per cent) responded. The mean age of the respondents was 72.6 years. Eight hundred and forty-nine respondents (71.2 per cent) were white, and 849 (71.2 per cent) were women. The participants reported that they had little or no pain in the knee at the time of the survey, regardless of the age at the time of the knee replacement, the body-mass index, or the length of time since the knee replacement. After adjustment for potential confounding variables, predictors of better physical function after the replacement were an absence of problems with the contralateral knee, primary knee replacement (rather than revision) (Indiana sample only), and a lower body-mass index (Indiana and western Pennsylvania samples). Four hundred and fifteen (85.2 per cent) of the 487 patients in the national sample were satisfied with the result of the knee replacement. In what we believe to be the first community-based study of the outcome of knee replacement, patients reported having significant (p = 0.0001) and persistent relief of pain, improved physical function, and satisfaction with the result two to seven years postoperatively. The findings of the present study suggest that age and obesity do not have a negative impact on patient-relevant outcomes (pain and physical function). Dissemination of these findings has the potential to increase appropriate referrals for knee replacement and thereby reduce the pain and functional disability due to osteoarthrosis of the knee.

Development of a Patient-Reported Measure of Function of the Knee*

Abstract: The purpose of the present study was to demonstrate the reliability, validity, and responsiveness of the Activities of Daily Living Scale of the Knee Outcome Survey, a patient-reported measure of functional limitations imposed by pathological disorders and impairments of the knee during activities of daily living. The study comprised 397 patients; 213 were male, 156 were female, and the gender was not recorded for the remaining twenty-eight. The mean age of the patients was 33.3 years (range, twelve to seventy-six years). The patients were referred to physical therapy because of a wide variety of disorders of the knee, including ligamentous and meniscal injuries, patellofemoral pain, and osteoarthrosis. The Activities of Daily Living Scale was administered four times during an eight-week period: at the time of the initial evaluation and after one, four, and eight weeks of therapy. Concurrent measures of function included the Lysholm Knee Scale and several global measures of function. The subjects also provided an assessment of the change in function, with responses ranging from greatly worse to greatly better, at one, four, and eight weeks. The Activities of Daily Living Scale was administered to an additional sample of fifty-two patients (thirty-two male and twenty female patients with a mean age of 31.6 years [range, fourteen to sixty-six years]) before and after treatment within a single day to establish test-retest reliability. Factor analysis revealed two dominant factors: one that reflected a combination of symptoms and functional limitations and the other, only symptoms. The internal consistency of the Activities of Daily Living Scale was substantially higher than that of the Lysholm Knee Scale (coefficient alpha, 0.92 to 0.93 compared with 0.60 to 0.73), resulting in a smaller standard error of measurement for the former scale. Validity was demonstrated by moderately strong correlations with concurrent measures of function, including the Lysholm Knee Scale (r = 0.78 to 0.86) and the global assessment of function as measured on a scale ranging from 0 to 100 points (r = 0.66 to 0.75). Analysis of variance with repeated measures revealed significant improvements in the score on the Activities of Daily Living Scale during the eight weeks of physical therapy (F2,236 = 108.13; p < 0.0001); post hoc testing indicated that the change in the score at eight weeks was significantly greater than the change at four weeks and that the change at four weeks was significantly greater than that at one week (p < 0.0001 for both). As had been hypothesized, the patients in whom the knee had somewhat improved had a significantly smaller change in the score, both at four weeks (F1,189 = 33.50; p < 0.001) and at eight weeks (F1,156 = 22.48; p < 0.001), compared with those in whom the knee had greatly improved. The test-retest reliability coefficient (intraclass correlation coefficient[2,1]) was 0.97. These results suggest that the Activities of Daily Living Scale is a reliable, valid, and responsive instrument for the assessment of functional limitations that result from a wide variety of pathological disorders and impairments of the knee.

Current Concepts Review - The Healing and Regeneration of Articular Cartilage*

Abstract: It is well established that damaged articular cartilage has a very limited potential for healing, and articular defects larger than two to four millimeters in diameter rarely heal even with such advances as the use of continuous passive motion26,36,70,98,101,128,130,138,162,163,208. Damage to articular cartilage is a common problem: in one study, it was associated with 16 percent (twenty-one) of 132 injuries of the knee that were sufficient to cause intra-articular bleeding88. Furthermore, damage to a joint surface can lead to premature arthritis128. Twyman et al. prospectively followed twenty-two knees in which osteochondritis dissecans had been diagnosed before skeletal maturity; at an average of thirty-four years, 32 percent had radiographic evidence of moderate or severe osteoarthritis235. Only 50 percent had a good or excellent functional result. Elderly patients (those who are sixty-five years of age or older) who have an arthritic condition can obtain dramatic relief from pain and restoration of function after total joint replacement. However, such procedures have higher rates of failure in young and early-middle-aged patients (those who are less than forty years old and those who are forty to sixty years old, respectively) than in elderly patients194. This leaves a large group of patients spanning a broad age-group, many of whom are in their prime, for whom there is no currently acceptable and reliable treatment. A typical example is that of a young, healthy individual who has arthrosis or osteochondritis dissecans following an injury to a joint. It might be possible to solve this patient's problems if the lost or damaged segment of articular cartilage inside the involved joint could be regenerated. After it had been restored, the …

Magnetic Resonance Imaging of Articular Cartilage in the Knee. An Evaluation with Use of Fast-Spin-Echo Imaging*

Abstract: The purpose of this study was to demonstrate that specialized magnetic resonance imaging provides an accurate assessment of lesions of the articular cartilage of the knee. Arthroscopy was used as the comparative standard. Eighty-eight patients who had an average age of thirty-eight years were evaluated with magnetic resonance imaging and subsequent arthroscopy because of a suspected meniscal or ligamentous injury. The magnetic resonance imaging was performed with a specialized sequence in the sagittal, coronal, and axial planes. Seven articular surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial plateaus) were graded prospectively on the magnetic resonance images by two independent readers with use of the 5-point classification system of Outerbridge, which was also used at arthroscopy. Six hundred and sixteen articular surfaces were assessed, and 248 lesions were identified at arthroscopy. Eighty-two surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep ulceration, fibrillation, or a flap without exposure of subchondral bone; and thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0 and 1 were regarded as disease-negative status and grades 2, 3, and 4 were regarded as disease-positive status. When the grades that had been assigned by reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent (144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the detection of a chondral lesion. Interobserver variability was minimum, as indicated by a weighted kappa statistic of 0.93 (almost perfect agreement). With use of this readily available modified magnetic resonance imaging sequence, it is possible to assess all articular surfaces of the knee accurately and thereby identify lesions that are amenable to arthroscopic treatment.

Metal release in patients who have had a primary total hip arthroplasty. A prospective, controlled, longitudinal study.

Abstract: There is an increasing recognition that, in the long term, total joint replacement may be associated with adverse local and remote tissue responses that are mediated by the degradation products of prosthetic materials. Particular interest has centered on the metal-degradation products of total joint

Percutaneous radiofrequency coagulation of osteoid osteoma compared with operative treatment.

Abstract: Osteoid osteoma, a benign bone tumor, has traditionally been treated with operative excision. A recently developed method for percutaneous ablation of the tumor has been proposed as an alternative to operative treatment. The relative outcomes of the two approaches to treatment have not previously been compared, to our knowledge. The rates of recurrence and of persistent symptoms were compared in a consecutive series of eighty-seven patients who were managed with operative excision and thirty-eight patients who were managed with percutaneous ablation with radiofrequency. Patients who had a spinal lesion were excluded. The minimum duration of follow-up was two years. There was a recurrence, defined as the need for subsequent intervention, after operative treatment in six (9 per cent) of sixty-eight patients who had been managed for a primary lesion and in two of nineteen who had been managed for a recurrent lesion. The average length of the hospital stay was 4.7 days for the patients who had a primary lesion and 5.1 days for those who had a recurrent lesion. There was a recurrence after percutaneous treatment in four (12 per cent) of thirty-three patients who had been managed for a primary lesion and in none of five who had been managed for a recurrent lesion. The average length of the hospital stay was 0.2 day for these thirty-eight patients. With the numbers available, we could detect no significant difference between the two treatments with regard to the rate of recurrence. The rate of persistent symptoms (that is, symptoms that did not necessitate additional treatment) was greater than the rate of recurrence. According to responses to a questionnaire, eight (30 per cent) of twenty-seven patients had persistent symptoms after operative treatment and six (23 per cent) of twenty-six patients had persistent symptoms after percutaneous treatment with radiofrequency. Two patients had complications after operative excision, necessitating a total of five additional operations. There were no complications associated with the percutaneous method. The results of the present study suggest that percutaneous ablation with radiofrequency is essentially equivalent to operative excision for the treatment of an osteoid osteoma in an extremity. The percutaneous method is preferred for the treatment of extraspinal osteoid osteoma because it generally does not necessitate hospitalization, it has not been associated with complications, and it is associated with a rapid convalescence.

Evaluation and treatment of infection at the site of a total hip or knee arthroplasty.

Abstract: Infection following total joint replacement remains a major problem that has not been solved during the last thirty years. The prevalence of infection at the Mayo Clinic between 1969 and 1996 was 1.7 per cent of 30,680 total hip arthroplasties and 2.5 per cent of 18,749 total knee arthroplasties. After primary operations, the rate of infection was 1.3 per cent of 23,519 hips and 2.0 per cent of 16,035 knees. After revision operations, the rate was 3.2 per cent of 7161 hips and 5.6 per cent of 2714 knees (Table I). The rate of infection has been remarkably constant despite the use of different regimens of antibiotic prophylaxis, operating-room configurations, operative techniques, and modes of fixation of the implant. Factors leading to deep infection must be considered with respect to the host, wound, operative technique, operating-room environment, and microbiological characteristics of the infecting organisms. A prompt diagnosis of infection will facilitate treatment and minimize morbidity. View this table: TABLE I PREVALENCE OF INFECTION AFTER TOTAL JOINT ARTHROPLASTY FOR THE YEARS 1969 THROUGH 1996 As stated, in discussing the etiology of infection, the host, wound, operating-room environment, operative technique, and microbiological characteristics of the infecting organisms must be considered. The patient as host is an important risk factor for infection. The operative wound is contaminated to some extent in all procedures, but the immune-defense mechanisms of the host prevent infection in most instances. Immunocompromised patients are clearly at increased risk for deep infection as are patients who have rheumatoid arthritis110,140. In a series of 4171 total knee replacements, an infection developed after sixteen (0.9 per cent) of 1854 replacements in patients who had osteoarthrosis compared with forty-five (2.2 per cent) of 2076 replacements in those who had rheumatoid arthritis140. In a series of 4240 total hip, knee, and …

Neer hemiarthroplasty and Neer total shoulder arthroplasty in patients fifty years old or less : Long-term results

Abstract: Seventy-eight Neer hemiarthroplasties and thirty-six Neer total shoulder arthroplasties were performed at our institution, between January 1, 1976, and December 31, 1985, in ninety-eight patients who were fifty years old or less. Two patients (two shoulders) died, and four patients (four shoulders) were lost to follow-up. The remaining seventy-four hemiarthroplasties (95 per cent) in sixty-four patients and thirty-four total shoulder arthroplasties (94 per cent) in thirty-one patients were included in the clinical analysis as the preoperative and operative records were complete and the patients had been followed for at least five years (mean, 12.3 years) or until revision. All 114 shoulders were included in the survivorship analysis. Both total shoulder arthroplasty and hemiarthroplasty resulted in significant long-term relief of pain (p < 0.0001) as well as improvement in active abduction (p < 0.0001) and external rotation (p < 0.0001). However, with the numbers available, we could not detect a significant difference between the two procedures with respect to these variables. A complete set of radiographs was available for sixty-eight (92 per cent) of the seventy-four shoulders that had a hemiarthroplasty and for thirty-two (94 per cent) of the thirty-four shoulders that had a total shoulder arthroplasty. A radiolucent line around the humeral component was noted after sixteen (24 per cent) of the hemiarthroplasties and after seventeen (53 per cent) of the total shoulder arthroplasties. A radiolucent line around the glenoid component was seen after nineteen (59 per cent) of the total shoulder arthroplasties. Erosion of the glenoid was found after forty-six (68 per cent) of the hemiarthroplasties. The results were graded according to a modification of the system of Neer et al. and of Cofield. Fifteen hemiarthroplasties led to an excellent result; twenty-four, a satisfactory result; and thirty-five, an unsatisfactory or unsuccessful result. Four total shoulder arthroplasties were followed by an excellent result; thirteen, a satisfactory result; and seventeen, an unsatisfactory or unsuccessful result. The estimated survival of the hemiarthroplasty prostheses (with 95 per cent confidence intervals) was 92 per cent (86 to 98 per cent) at five years, 83 per cent (75 to 93 per cent) at ten years, and 73 per cent (59 to 88 per cent) at fifteen years. Analysis of the results in association with the two major diagnoses revealed that the risk of revision was higher for the thirty shoulders that had the hemiarthroplasty for the treatment of the sequelae of trauma than for the twenty-eight that had the procedure for the treatment of rheumatoid arthritis (p = 0.017). The estimated survival of the total shoulder prostheses (with 95 per cent confidence intervals) was 97 per cent (92 to 100 per cent) at five years, 97 per cent (91 to 100 per cent) at ten years, and 84 per cent (70 to 100 per cent) at fifteen years. The risk of revision was higher for the seven shoulders that had had a tear of the rotator cuff at the time of the operation than for the twenty-seven that had not had one (p = 0.029). The data from the present study indicate that a shoulder arthroplasty provides marked long-term relief of pain and improvement in motion; however, nearly half of all young patients who have a shoulder arthroplasty have an unsatisfactory result according to a rating system. Care should be exercised when either a hemiarthroplasty or a total shoulder arthroplasty is offered to patients who are fifty years old or less.

Arthroscopic Repair of Full-Thickness Tears of the Rotator Cuff*

Abstract: We present the results of arthroscopic repair of full-thickness tears of the rotator cuff in seventy-three patients (thirty-nine men and thirty-four women). The average age of the patients at the time of the operation was 60.7 years (range, thirty-one to eighty-two years). All of the patients were followed for at least two years (average, thirty months; range, twenty-four to forty months). The shoulders were evaluated with the rating scale of the University of California at Los Angeles, the shoulder index of the American Shoulder and Elbow Surgeons, and the functional rating scale of Constant and Murley. In addition, the patients completed the Short-Form 36 Health Survey (SF-36) preoperatively and at the yearly follow-up evaluations. Eleven tears were small (less than one centimeter in length), forty-five were medium (one to three centimeters), eleven were large (more than three to five centimeters), and six were massive (more than five centimeters). The average length of the tear was twelve millimeters, and the average width was twenty-seven millimeters. Sixty-nine tendons were repaired anatomically, and four were repaired an average of three millimeters (range, two to eight millimeters) medial to the anatomical insertion of the tendon. An average of 2.3 (range, one to four) suture anchors were used in the repair. Sixty-three glenohumeral joints were normal, and ten had an intra-articular lesion. Seven patients had a concomitant resection of the acromioclavicular joint. The average duration of the operation was fifty-six minutes (range, thirty-five to ninety minutes). The active and passive ranges of motion improved significantly after the procedure (p = 0.0001). The strength of resisted elevation improved from 7.5 to 14.0 pounds (3.4 to 6.3 kilograms) (p = 0.0001). The average total score according to the rating scale of the University of California at Los Angeles improved from 12.4 to 31.1 points; the average total score according to the shoulder index of the American Shoulder and Elbow Surgeons, from 30.7 to 87.6 points; and the average absolute score according to the rating system of Constant and Murley, from 41.7 to 83.6 points (p = 0.0001 for all comparisons). The average score for the pain component of the rating scale of the University of California at Los Angeles improved from 2.4 to 8.6 points; fifty-seven (78 per cent) of the seventy-three patients rated the relief of pain as good or excellent on the visual-analog scale. The average score for satisfaction improved from 0.4 to 4.6 points; sixty-six patients (90 per cent) rated their satisfaction as good or excellent at the time of the most recent examination. None of the shoulders were rated as good or excellent before the operation, whereas sixty-one (84 per cent) were so rated at the most recent follow-up evaluation after the index procedure. In addition, significant improvements (p = 0.0015) were noted in the scales and summary measures of the SF-36. Arthroscopic repair of full-thickness tears of the rotator cuff produced satisfactory results with regard to traditional orthopaedic criteria as well as with regard to patient-assessed criteria such as satisfaction, pain relief, and general health. The arthroscopic method offers several advantages, including smaller incisions, access to the glenohumeral joint for the inspection and treatment of intra-articular lesions, no need for detachment of the deltoid, and less soft-tissue dissection. However, these advantages must be considered against the technical difficulty of the method, which limits its application to surgeons who are skilled in both open and arthroscopic procedures on the shoulder.

Quantitative assessment of walking activity after total hip or knee replacement.

Abstract: Accumulating data suggest that the amount of use, and not simply the duration in situ, influences the wear and survival of total joint replacements. An electronic, digital pedometer was used to record the number of steps taken by 111 non-randomized volunteers who had had at least one total hip or knee replacement. The patients averaged 4988 steps per day, which extrapolates to approximately 0.9 million cycles per year for each joint of the lower extremity. Average activity ranged widely from 395 to 17,718 steps per day, an approximately forty-five-fold difference. The most active patient walked more than 3.5 times the average number of steps per day. Age was significantly associated with activity (p = 0.048), but there was a high degree of variability (standard deviation, 3040 steps per day). Patients who were less than sixty years old walked 30 per cent more on average than those who were sixty years old or more (p = 0.023). Men walked 28 per cent more on average than women (p = 0.037), and men who were less than sixty years old walked 40 per cent more on average than the rest of the patients (p = 0.011). These data indicate that individual differences in the activity of the patient can be a substantial source of variability in rates of polyethylene wear in vivo. The pedometer is an inexpensive investigational tool with many potential applications, including standardizing wear measurements of joint replacements on the basis of gait cycles rather than time. This quantitative approach may provide prognostic information regarding the survival of joint prostheses. Pedometer data may also be useful for quantitative assessment of walking ability in outcome studies.

Use of an intramedullary hip-screw compared with a compression hip-screw with a plate for intertrochanteric femoral fractures. A prospective, randomized study of one hundred patients.

Abstract: One hundred elderly patients who had an intertrochanteric femoral fracture were randomized to treatment with a compression hip-screw with a plate (fifty patients) or a new intramedullary device, the intramedullary hip-screw (fifty patients). All patients were followed prospectively for one year or until death. A detailed assessment of the functional status and the plain radiographs of the hip was performed one, three, six, and twelve months postoperatively. The two treatment groups were strictly comparable. The operative time needed to insert the intramedullary hip-screw was significantly greater than that needed to insert the compression hip-screw with the plate (p = 0.02), but use of the intramedullary hip-screw was associated with less estimated intraoperative blood loss (p = 0.011). The prevalence of perioperative complications, such as bronchopneumonia, cardiac failure, and urinary tract infection, was comparable in the two treatment groups. There were one intraoperative fracture of the femoral shaft and two intraoperative fractures of the greater trochanter in the group managed with the intramedullary hip-screw. One patient had pulling-out of the compression hip-screw on the seventh postoperative day. Four patients had a trochanteric wound hematoma, without infection, after insertion of an intramedullary hip-screw. All but one of the fractures healed. The one non-union, which was in a patient who had a compression hip-screw, was treated with a hemiarthroplasty. The mortality rate was similar in the two treatment groups. The patients who had an intramedullary hip-screw had, on the average, significantly better mobility at one (p < 0.0001) and three months (p = 0.0013) postoperatively. This difference was no longer seen at six and twelve months, although the patients who had an intramedullary hip-screw still had significantly better walking ability outside the home at those time-periods (p = 0.05). The compression hip-screw was removed from two patients because of pain in the mid-portion of the thigh, which had begun after consolidation of the fracture. Fourteen patients who had an intramedullary hip-screw had cortical hypertrophy at the level of the tip of the nail at twelve months postoperatively. Cortical hypertrophy was significantly related to the use of two interlocking screws (p = 0.02). Six of these patients also had pain in the mid-portion of the thigh, and the nail had been locked with two screws in five of them. Three of the six patients had the hardware removed because of the pain, and the symptoms resolved. A seventh patient had pain without cortical hypertrophy. The intramedullary hip-screw device was associated with significantly less sliding of the lag-screw and subsequent shortening of the limb in the region of the thigh (p = 0.012 and 0.019, respectively); these differences were more pronounced when the unstable fractures in the two treatment groups were compared (p < 0.001).

Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy : Two to seventeen-year follow-up

Abstract: We reviewed the cases of 108 patients with cervical spondylotic myelopathy who had been managed with anterior decompression and arthrodesis at our institution. Operative treatment consisted of anterior discectomy, partial corpectomy, or subtotal corpectomy at one level or more, followed by placement of autogenous bone graft from the iliac crest or the fibula. At the latest follow-up examination, thirty-eight of the eighty-two patients who had had a preoperative gait abnormality had a normal gait, thirty-three had an improvement in gait, six had no change, four had improvement and later deterioration, and one had a worse gait abnormality. Of the eighty-seven patients who had had a preoperative motor deficit, fifty-four had complete recovery; twenty-six, partial recovery; six, no change; and one had a worse deficit. The average grade according to the system of Nurick improved from 2.4 preoperatively to 1.2 (range, 0.0 to 5.0) postoperatively. A pseudarthrosis developed in sixteen patients, thirteen of whom had had a multilevel discectomy. Only one of thirty-eight arthrodeses that had been performed with use of a fibular strut graft was followed by a non-union. An unsatisfactory outcome with respect to pain was significantly associated with pseudarthrosis (p < 0.001). The development of complications other than non-union was associated with a history of one previous operative procedure or more (p = 0.005). Recurrent myelopathy was rare, but when it occurred it was associated with a pseudarthrosis or stenosis at a new level. The strongest predictive factor for recovery from myelopathy was the severity of the myelopathy before the operative intervention--that is, better preoperative neurological function was associated with a better neurological outcome. Anterior decompression and arthrodesis with autogenous bone-grafting can be performed safely, and is associated with a high rate of neurological recovery, functional improvement, and pain relief, in patients who have cervical spondylotic myelopathy.

The Coonrad-Morrey Total Elbow Arthroplasty in Patients Who Have Rheumatoid Arthritis. A Ten to Fifteen-Year Follow-up Study*

Abstract: Sixty-nine patients (seventy-eight elbows) who had rheumatoid arthritis were managed with a Coonrad-Morrey total elbow arthroplasty between 1981 and 1986. At the time of the present review, forty-one patients (forty-six elbows) were alive and had been followed for at least ten years after the procedure (Group 1). The remaining twenty-eight patients (thirty-two elbows) had died or had had a revision less than ten years after the procedure or had been followed for less than ten years (Group 2). The patients in Group 1 had a younger mean age at the time of the procedure, but all other preoperative parameters were similar for both groups. At the latest follow-up evaluation, 97 per cent of the elbows (forty-five of the forty-six in Group 1 and thirty-one of the thirty-two in Group 2) were not painful or were only mildly painful. The mean arc of flexion-extension was 28 to 131 degrees; this represents an increase of 13 degrees (15 degrees in Group 1 and 7 degrees in Group 2) compared with the preoperative value. The mean arc of pronation was 68 degrees, and the mean arc of supination was 62 degrees; this represents an increase of 21 degrees. The results for seventy-four of the seventy-eight elbows (all forty-six in Group 1 and twenty-eight of the thirty-two in Group 2) were considered satisfactory by the patients. One patient thought that the status of the elbow was unchanged compared with preoperatively, and three thought that it was worse. Seventy-six of the seventy-eight elbows had long-term radiographic evaluation; the two remaining elbows were excluded because a resection arthroplasty had been performed. There were two loose ulnar components; one was associated with an infection, and the other had been causing no symptoms at the time of the patient's death. In addition, both components were radiographically loose in an elbow that had had a revision without cement after a previous total elbow arthroplasty. Five bushings (7 per cent) were completely worn, and six (8 per cent) were partially worn. Complications occurred in eleven elbows (14 per cent) and were serious, necessitating reoperation, in ten (13 per cent). Delayed complications included three avulsions of the triceps, two deep infections, two ulnar fractures, and one fracture of an ulnar component. In addition, two elbows were revised because of aseptic loosening. No patient had persistent ulnar neuritis or serious skin complications. At the latest clinical follow-up evaluation, according to the Mayo elbow performance score, forty-three of the seventy-eight elbows had an excellent result; twenty-six, a good result; seven, a fair result; and two (both in Group 2), a poor result. The rate of survival of the prosthesis was 92.4 per cent, with 86 per cent good or excellent and 14 per cent fair or poor results.

Total Ankle Arthroplasty: a Unique Design. Two to Twelve-Year Follow-up*

Abstract: We evaluated the intermediate-term results of a novel total ankle arthroplasty that includes insertion of the components without cement and arthrodesis of the tibiofibular syndesmosis as part of the operative procedure. One hundred consecutive Agility ankle replacements were performed in ninety-five patients between 1984 and 1993. At the time of follow-up, eighty-three patients (eighty-six ankles) were alive and twelve patients (fourteen ankles) had died. Five (6 per cent) of the eighty-six ankles in the living patients had been revised. Including the components that had been revised for loosening, twenty-one (twelve tibial and nine talar) components had migrated. Delayed union of the syndesmosis (twenty-eight ankles) and non-union of the syndesmosis (nine ankles) were associated with the development of lysis around the tibial component. Non-union of the syndesmosis was also associated with migration of the tibial component and circumferential radiolucency around that component. In addition to the patients who died, one patient had a resection of the implant with subsequent arthrodesis. The remaining eighty-two patients (eighty-five ankles) were the basis for the clinical evaluation in the study. The average age at the time of the procedure was sixty-three years (range, twenty-seven to eighty-one years). At the time of the most recent follow-up (range, 2.8 to 12.3 years; average, 4.8 years), forty-seven (55 per cent) of the remaining eighty-five ankles were not painful and twenty-four (28 per cent) were only mildly painful. The range of motion of the fifty-six ankles that were examined at the time of follow-up averaged 36 degrees (range, 10 to 64 degrees), and the results for seventy-nine (93 per cent) of the eighty-five ankles were satisfactory to the patients.

Dural Tears Secondary to Operations on the Lumbar Spine. Management and Results After a Two-Year-Minimum Follow-up of Eighty-eight Patients*

Abstract: We reviewed the results of acute management of patients who had sustained a dural tear during an operation on the lumbar spine, and we attempted to determine the long-term sequelae of this complication. In the five years from July 1989 to July 1994, 641 consecutive patients had a decompression of the lumbar spine, performed by the senior one of us; of these patients, eighty-eight (14 percent) sustained a dural tear, which was repaired during the operation. The duration of follow-up ranged from two to eight years (average, 4.3 years). Postoperative management consisted of closed suction wound drainage for an average of 2.1 days and bed rest for an average of 2.9 days. Of the eighty-eight procedures that resulted in a dural tear, forty-five were revisions; these revisions were performed after an average of 2.2 previous operations on the lumbar spine, all of which resulted in a scar adherent to the dura. Only eight patients had headaches related to the spinal procedure and photophobia in the postoperative period; these symptoms resolved in all but two patients, both of whom had had a revision operation. Each of the two patients had symptoms of a persistent leak of spinal fluid and needed a reoperation for repair. Overall, seventy-six patients had a good or excellent result and twelve had a poor or satisfactory result with some residual back pain. One patient had arachnoiditis, and another had symptoms of viral meningitis one month postoperatively. A dural tear that occurs during an operation on the lumbar spine can be treated successfully with primary repair followed by bed rest. Such a tear does not appear to have any long-term deleterious effects or to increase the risk of postoperative infection, neural damage, or arachnoiditis. Closed suction wound drainage does not seem to aggravate the leak and can be used safely in the presence of a dural repair.

Glenohumeral Deformity Secondary to Brachial Plexus Birth Palsy

Abstract: Ninety-four patients who had brachial plexus birth palsy were entered into a prospective study to evaluate the association between persistent palsy, age-related musculoskeletal deformity, and functional limitations. Of these patients, forty-two had either computerized tomography or magnetic resonance imaging to assess the presence and degree of incongruity of the glenohumeral joint, deformity of the humeral head, and hypoplasia of the glenoid as part of the preoperative planning for a reconstructive operation. Functional ability was rated with use of the classification of Mallet, on a scale of 1 to 5. The mean glenoscapular angle (the degree of retroversion of the glenoid) on the affected side was -25.7 degrees compared with -5.5 degrees on the unaffected side. Twenty-six (62 per cent) of the forty-two shoulders had evidence of posterior subluxation of the humeral head, with a mean of only 25 per cent (range, 0 to 50 per cent) of the head being intersected by the scapular line. Progressive deformity was found with increasing age (p < 0.001). The natural history of untreated brachial plexus birth palsy with residual weakness is progressive glenohumeral deformity due to persistent muscle imbalance. The status of the glenohumeral joint must be addressed when the choice between tendon transfer and humeral derotation osteotomy for reconstruction of the shoulder is considered for these patients.

Biomechanical and Histological Evaluation of a Calcium Phosphate Cement

Abstract: It is often difficult to achieve stable fixation of a comminuted fracture associated with a metaphyseal defect. The injection of a resorbable cement into an osseous defect may help to stabilize the fracture and to maintain osseous integrity as the cement is resorbed and replaced by bone. The purpose of the present study was to evaluate the repair of a metaphyseal defect after treatment with an injectable calcium-phosphate cement. The injectable cement undergoes isothermic curing in vivo to form a carbonated apatite (dahllite) with a compressive strength of twenty-five megapascals. Either the cement or allograft bone was placed in proximal tibial metaphyseal and distal femoral metaphyseal defects in seventy-two dogs and was evaluated from twenty-four hours to seventy-eight weeks postoperatively. Histological examination showed that the cement was osteoconductive; nearly the entire surface area was covered with bone two weeks after the injection. The resulting bone-cement composite underwent gradual remodeling over time in a pattern that was qualitatively similar to the remodeling of normal cortical and cancellous bone. Osteoclasts were found to resorb the cement and were usually associated with adjacent new-bone formation. With increasing time in vivo, the cement was penetrated by small blood vessels that became surrounded by circumferential lamellae of bone and that closely resembled evolving haversian systems. This process occurred more rapidly in the cortex than in the medulla. Mechanical testing showed that, by eight weeks, the tibiae that had been treated with cement had reached nearly 100 per cent of the torsional strength of the contralateral, control (intact) tibiae; this finding paralleled the histological observations of bone apposition to the cement and rapid restoration of the cortex. At no time was fibrous tissue present between the cement and the bone, and there was no evidence of acute inflammation. Small particles of cement were present within occasional macrophages during the process of cement resorption, but the macrophages disappeared over time and were not associated with fibrosis or unexpected resorption of bone. Resorption of the cement was incomplete in the medullary area at seventy-eight weeks, but the pattern of cement resorption and bone-remodeling suggested gradual restoration of a physiological proportion of bone and marrow in both the cortical and the medullary region with maintenance of mechanical function.

Total knee arthroplasty in morbidly obese patients.

Abstract: We reviewed the clinical outcomes of fifty primary total knee arthroplasties that had been performed with cement in forty patients who were considered morbidly obese (a Quetelet index of more than forty). These results were compared with those of 1768 similar procedures, performed during the same time-period by the same surgeon, in 1539 patients who were not morbidly obese (controls). At a mean of approximately five years postoperatively, there was a significant difference between the morbidly obese patients and the control group with regard to the knee and functional scores (84 and 53 points compared with 92 and 67 points; p < 0.00005 for both scores). No significant difference was detected, with the numbers available, with regard to the range of motion or the radiographic score (p = 0.77). The rate of perioperative complications was significantly higher in the morbidly obese patients (p < 0.00005). Of the fifty knees in these patients, eleven (22 percent) had a wound complication, five (10 percent) had an infection, and four (8 percent) had an avulsion of the medial collateral ligament. The five infections developed within twenty weeks after the operation, and three were associated with a wound complication. In comparison, thirty-five (2 percent) of the 1768 knees in the control group had a wound complication, eleven (0.6 percent) had an infection, and none had an avulsion of the medial collateral ligament. We concluded that total knee arthroplasty in morbidly obese patients can be successful but is associated with an increased rate of perioperative complications, including problems with wound-healing, infection, and avulsion of the medial collateral ligament. Alterations in the operative technique for soft-tissue closure and protection of the medial collateral ligament have decreased the rates of complications related to wound-healing and the medial collateral ligament.

The Column Procedure: A Limited Lateral Approach for Extrinsic Contracture of the Elbow*

Abstract: Thirty-eight elbows (thirty-seven patients) with an extrinsic contracture were treated operatively with a limited lateral approach to the anterior and posterior aspects of the capsule. Because the procedure elevates muscles from the anterior and posterior aspects of the lateral supracondylar osseous ridge, we called it the column procedure. The mean preoperative arc of flexion was 49 degrees (from 52 to 101 degrees). At a mean of forty-three months (range, twenty-four to seventy-four months) postoperatively, the mean arc of flexion was 94 degrees (from 27 to 121 degrees). The mean total gain in the arc of flexion-extension was 45 degrees; thirty-four elbows (89 percent) had an improved range of motion at the latest follow-up examination. Overall, thirty-one elbows (82 percent) had a satisfactory result. Greater improvement was obtained in elbows that had had severe stiffness (a total arc of 31 to 60 degrees) or very severe stiffness (a total arc of 30 degrees or less) or that had had a combined flexion and extension contracture. A complication occurred in four elbows (11 percent). A hematoma developed in two elbows and impaired the final outcome in one of them. Two elbows had transient ulnar paresthesia, which resolved spontaneously. The arc of flexion obtained at the time of the operation was lost in ten elbows (26 percent) after an initial period of improvement; at the latest follow-up evaluation, four of these elbows had a mean decrease in the arc of flexion of 24 degrees compared with preoperatively. The column procedure is associated with a low rate of complications and is safe and effective for the treatment of a limitation in flexion or extension resulting from an extrinsic contracture of the elbow.

Treatment of infection with débridement and retention of the components following hip arthroplasty.

Abstract: Forty-two patients (forty-two hips) who had an infection following a hip arthroplasty were managed with open debridement, retention of the prosthetic components, and antibiotic therapy. After a mean duration of follow-up of 6.3 years (range, 0.14 to twenty-two years), only six patients (14 per cent) -- four of nineteen who had had an early postoperative infection and two of four who had had an acute hematogenous infection -- had been managed successfully. Of the remaining thirty-six patients, three (7 per cent of the entire group) were being managed with chronic suppression with oral administration of antibiotics and thirty-three (79 per cent of the entire group) had had a failure of treatment. All nineteen patients who had a late chronic infection were deemed to have had a failure of treatment. Debridement had been performed at a mean of six days (range, two to fourteen days) after the onset of symptoms in the patients who had been managed successfully and at a mean of twenty-three days (range, three to ninety-three days) in those for whom treatment had failed. Debridement with retention of the prosthesis is a potentially successful treatment for early postoperative infection or acute hematogenous infection, provided that it is performed in the first two weeks after the onset of symptoms and that the prosthesis previously had been functioning well. In our experience, this procedure has not been successful when it has been performed more than two weeks after the onset of symptoms. Retention of the prosthesis should not be attempted in patients who have a chronic infection at the site of a hip arthroplasty as this approach universally fails.

Mechanoreceptors in joint function.

Abstract: Most surgeons and investigators consider ligaments to be passive stabilizers of the joints. However, more than 100 years ago, clinicians and investigators recognized the presence and potential roles of mechanoreceptors in the function of joints52,93,128. Perhaps because of the frequency of injuries of the anterior cruciate ligament, the functional impairment resulting from them, and the issue of whether the anterior cruciate ligament should be removed during total knee replacement, the role of mechanoreceptors in the anterior cruciate ligament recently has attracted considerable attention. It is important to ascertain the role of mechanoreceptors in the function of intra-articular ligaments in order to determine the future direction of joint reconstruction. Their importance, or lack thereof, will determine, in part, whether efforts should be directed more toward preservation of the receptors or whether the emphasis should remain on purely mechanical and kinematic aspects of joint function. Joint mechanoreceptors have been most often studied in the knee, with most recent investigations focusing on the anterior cruciate ligament. In exploring the function of mechanoreceptors in the knee, we do not intend to imply that mechanoreceptors in other joints are not important; our review is merely reflecting the literature relating to loss of function of the anterior cruciate ligament due to rupture (injury) or transection (operative treatment) rather than congenital laxity. The presence of mechanoreceptors in the anterior cruciate ligament41,66,104 has led several authors to suppose that these receptors influence motor function and, conversely, that their loss leads to dysfunction11,40,81. This notion is reinforced by the lack of a clear association between the functional outcome and the amount of passive laxity, not only after non-operative treatment23,38,118,142 of tears of the anterior cruciate …

Periprosthetic fracture of the femur after total hip arthroplasty: treatment and results to date.

Abstract: Postoperative periprosthetic femoral fractures have become increasingly common during the last decade. A wide range of problems, such as comminution and bone loss, are seen in association with these fractures, and the additional challenge of a loose femoral component is commonly encountered. When a femoral fracture occurs in a patient in whom the femoral component is in place, reconstruction may be reasonably straightforward or it may be nearly impossible. Options for treatment have included the use of traction, casts, and external braces; operative reduction with internal fixation; numerous revision procedures involving insertion of a long-stem femoral component for stabilization of the fracture; and bone-grafting with use of either autogenous grafts or allografts1-3,5-12,19-24,35,36,38-42,45,49-51,55,56. These fractures must be treated according to their individual characteristics, the status of the implant, associated medical conditions, and the patient's level of physical activity2,11,23,35. Knowledge of the results in previously reported series and information regarding the range of treatment options can facilitate optimum decision-making with regard to these injuries. The number of patients who are seen with a postoperative periprosthetic fracture of the femur has increased steadily at our institution during the last twenty-five years (Fig. 1). Between 1989 and 1993, fracture was the second leading cause of revision hip arthroplasty at the Mayo Clinic, ranking after loosening of the implant and before dislocation and infection (Fig. 2). Reports have suggested an over-all prevalence of between 0.1 and 1.1 per cent, with ten postoperative periprosthetic fractures (0.2 per cent) found in 5400 patients in one of the largest series. However, these estimates apply to patients who had a femoral …

Validity of Observer-Based Aggregate Scoring Systems as Descriptors of Elbow Pain, Function, and Disability*

Abstract: Current elbow-scoring systems are based on the observer-derived assessment of a variety of clinical and functional criteria, which are scored separately and then aggregated. The aggregate score then is assigned a categorical ranking that ranges from excellent to poor. The developers of different elbow-scoring systems have chosen different outcome criteria, assigned different weights to each criterion, and accorded different ranges of values to each categorical ranking. Five different elbow-scoring systems (the Mayo elbow-performance index and the systems of Broberg and Morrey, Ewald et al., The Hospital for Special Surgery, and Pritchard) were used to evaluate the same group of patients. The validity of the scoring systems was determined with use of visual-analog scales for the assessment of pain and function, patient and physician-derived ratings of the severity of impairment of the elbow, and two functional questionnaires completed by the patient (the Disabilities of the Arm, Shoulder and Hand questionnaire and the Modified American Shoulder and Elbow Surgeons patient self-evaluation form). The study sample consisted of sixty-nine patients who had sought treatment at one of two tertiary referral clinics because of problems related to the elbow. Pearson product-moment correlation coefficients were used to compare the raw aggregate scores, and kappa statistics were used to determine the level of agreement among the categorical rankings (excellent, good, fair, and poor). Examination of the five scoring systems revealed a remarkable lack of concordance with regard to the aspects of elbow function that were assessed. Good correlation was observed when the systems were compared on the basis of raw scores (Pearson product-moment correlation coefficients, 0.79 to 0.90), but only slight-to-moderate correlation was noted when the systems were compared on the basis of categorical rankings (quadratic weighted kappa coefficients, 0.18 to 0.49). Validity testing showed the system of Ewald et al. and the Mayo elbow-performance index to be the most discriminating, the system of Pritchard to be the least discriminating, and the system of The Hospital for Special Surgery and the system of Broberg and Morrey to be intermediate. The scores determined with the elbow-scoring systems demonstrated only moderate correlation with the score for function on the visual analog scale (Pearson product-moment correlation coefficients, 0.44 to 0.66), whereas those derived from the functional questionnaires completed by the patient demonstrated moderate-to-good correlation with the score for function (Pearson product-moment correlation coefficients, 0.72 and 0.80).

Changes in Interstitial Pressure and Cross-Sectional Area of the Cubital Tunnel and of the Ulnar Nerve with Flexion of the Elbow. An Experimental Study in Human Cadavera*

Abstract: The purpose of this study was to determine the relationship between the ulnar nerve and the cubital tunnel during flexion of the elbow with use of magnetic resonance imaging and measurements of intraneural and extraneural interstitial pressure Twenty specimens from human cadavera were studied with the elbow in positions of incremental flexion With use of magnetic resonance imaging, cross-sectional images were made at each of three anatomical regions of the cubital tunnel: the medial epicondyle, deep to the cubital tunnel aponeurosis, and deep to the flexor carpi ulnaris muscle The cross-sectional areas of the cubital tunnel and the ulnar nerve were calculated and compared for different positions of elbow flexion Interstitial pressures were measured with use of ultrasonographic imaging to allow a minimally invasive method of placement of the pressure catheter, both within the cubital tunnel and four centimeters proximal to it, at 10-degree increments from 0 to 130 degrees of elbow flexion As the elbow was moved from full extension to 135 degrees of flexion, the mean cross-sectional area of the three regions of the cubital tunnel decreased by 30, 39, and 41 per cent and the mean area of the ulnar nerve decreased by 33, 50, and 34 per cent These changes were significant in all three regions of the cubital tunnel (p < 005) The greatest changes occurred in the region beneath the aponeurosis of the cubital tunnel with the elbow at 135 degrees of flexion The mean intraneural pressure within the cubital tunnel was significantly higher than the mean extraneural pressure when the elbow was flexed 90, 100, 110, and 130 degrees (p < 005) With the elbow flexed 130 degrees, the mean intraneural pressure was 45 per cent higher than the mean extraneural pressure (p < 0001) Similarly, with the elbow flexed 120 degrees or more, the mean intraneural pressure four centimeters proximal to the cubital tunnel was significantly higher than the mean extraneural pressure (p < 001) Relative to their lowest values, intraneural pressure increased at smaller angles of flexion than did extraneural pressure, both within the cubital tunnel and proximal to it With the numbers available, we could not detect any significant difference in intraneural pressure measured, either at the level of the cubital tunnel or four centimeters proximal to it, after release of the aponeurotic roof of the cubital tunnel CLINICAL RELEVANCE: These findings demonstrate that the cubital tunnel is a dynamic region morphologically Both the cubital tunnel and the ulnar nerve change in area by as much as 50 per cent as the normal elbow is flexed and extended, with substantial flattening of the ulnar nerve but no evidence of direct, focal compression These morphological findings corresponded well with measurements of interstitial pressure, which demonstrated an initial increase in intraneural pressure without a corresponding increase in extraneural pressure This indicates that traction on the ulnar nerve is a major cause of increased intraneural pressure in association with flexion of the elbow