Showing papers in "Journal of Bone and Joint Surgery, American Volume in 1980"

The Biological Effect of Continuous Passive Motion on the Healing of Full-Thickness Defects in Articular Cartilage. An Experimental Investigation in the Rabbit

Abstract: A new concept, continuous passive motion of a synovial joint in vivo, was investigated to determine its biological effect on the healing of full-thickness articular cartilage defects that penetrate the subchondral bone of knee joints of adolescent and adult rabbits. The effect of continuous passive motion was compared with the effects of immobilization and of intermittent active motion. This investigation included assessment of 480 defects in the knees of 120 adolescent rabbits and assessment of 108 defects in the knees of twenty-seven adult rabbits. The continuous passive motion was well tolerated by these animals, whose general well-being was undisturbed. The healing of the defects at weekly intervals up to four weeks was assessed by gross examination and by an analysis of two indices of healing determined by light microscopy: (1) the nature of the reparative tissue, and (2) the degree of metachromasia of the matrix as demonstrated by toluidine-blue staining. At three weeks this assessment revealed that in the adolescent rabbits, healing of the defects by hyaline articular cartilage was present in 8 per cent of forty defects in ten animals whose knees were immobilized, in 9 per cent of forty defects in ten animals whose knees were permitted intermittent active motion, and in 52 per cent of forty defects in ten animals whose knees were managed immediately after operation by continuous passive motion. At three weeks, in the adult animals, healing of the defects by hyaline articular cartilage was present in 3 per cent of thirty-six defects in nine animals whose knees were immobilized, in 5 per cent of thirty-six defects in nine animals whose knees were permitted intermittent active motion, and in 44 per cent of thirty-six defects in nine animals whose knees were managed immediately after operation by continuous passive motion. Thus, the metaplasia of the healing tissue within the defects from undifferentiated mesenchymal tissue to hyaline articular cartilage was not only much more rapid but also much more complete with continuous passive motion than with either immobilization or intermittent active motion.

Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder. A preliminary report.

Abstract: In thirty-six patients (forty shoulders) with involuntary inferior and multidirectional subluxation and dislocation, there had been failure of standard operations or uncertainty regarding diagnosis or treatment. Clinical evaluation of these patients stressed meticulous psychiatric appraisal, conservative treatment, and repeated examination of the shoulder. All patients were treated by an inferior capsular shift, a procedure in which a flap of the capsule reinforced by overlying tendon is shifted to reduce capsular and ligamentous redundancy on all three sides. This technique offers the advantage of correcting multidirectional instability through one incision without damage to the articular surface. One shoulder began subluxating again within seven months after operation, but there have been no other unsatisfactory results to date. Seventeen shoulders were followed for more than two years.

The development of mature gait.

Abstract: The development of mature gait. D Sutherland;R Olshen;L Cooper;S Woo; The Journal of Bone & Joint Surgery

A Study of Lower-Limb Mechanics During Stair-Climbing

Abstract: The motions, forces, and moments at the major joints of the lower limbs of ten men ascending and descending stairs were analyzed using an optoelectronic system, a force-plate, and electromyography. The mean values for the maximum sagittalplane motions of the hip, knee, and ankle were 42, 88, and 27 degrees, respectively. The mean maximum net flexion-extension moments were: at the hip, 123.9 newton-meters going up and 112.5 newton-meters going down stairs; at the knee, 57.1 newton-meters going up and 146.6 newton-meters going down stairs; and at the ankle, 137.2 newton-meters going up and 107.5 newton-meters going down stairs. When going up and down stairs large moments are present about weight-bearing joints, but descending movements produce the largest moments. The magnitudes of these moments are considerably higher than those produced during level walking.

Complications of Colles' fractures.

Abstract: Patients with Colles' fractures have serious complications more frequently than is generally appreciated. A study of 565 fractures revealed 177 (31 per cent) with such complications as persistent neuropathies of the median, ulnar, or radial nerves (forty-five cases), radiocarpal or radio-ulnar arthrosis (thirty-seven cases), and malposition-malunion (thirty cases). Other complications included tendon ruptures (seven), unrecognized associated injuries (twelve), Volkmann's ischemia (four cases), finger stiffness (nine cases), and shoulder-hand syndrome (twenty cases). In many patients, incomplete restoration of radial length or secondary loss of the reduction position caused the complications.

Arthroscopy in acute traumatic hemarthrosis of the knee. Incidence of anterior cruciate tears and other injuries.

Abstract: In a prospective study, all injured knees that had traumatic hemarthrosis and absent or negligible instability on clinical examination underwent arthroscopy and examination under anesthesia. Eighty-five knees (eighty-three patients) were examined over a 125-week period. Some degree of disruption of the anterior cruciate ligament was found in sixty-one (72 per cent) of the knees (a partial tear in 28 per cent and a complete tear in 44 per cent), frequently associated with an injury of varying severity to other joint structures. These included minor ligament sprains without laxity in 41 per cent, a major associated ligament injury in 21 per cent, meniscal tears in 62 per cent (partial in 30 per cent and complete in 70 per cent), and a femoral chondral fracture or surface defect in 20 per cent. A popping sensation at injury occurred in 33 per cent of knees with a normal anterior cruciate ligament and in 36 per cent of those with a disruption. One-third of the knees had no to slight pain at the time of injury. The anterior drawer test without anesthesia was positive in only 24 per cent of the knees with a torn anterior cruciate ligament. We concluded that: (1) a traumatic hemarthrosis indicates a significant knee injury; (2) examination under anesthesia plus arthroscopy allows a more accurate diagnosis of injury to joint structures; and (3) such data are required for a rational treatment program to be outlined.

Long-term results of treatment of congenital club foot.

Abstract: In seventy patients with 104 club feet that were treated at our hospital and followed for ten to twenty-seven years after treatment, the functional results were satisfactory according to our rating system in 88.5 per cent of the feet, and 90 per cent of the patients were satisfied with both the appearance and function of the club foot. However, in the majority of the patients, foot and ankle motion was limited and the talocalcaneal angles as seen on the anteroposterior and lateral roentgenograms were not fully corrected. The amount of motion in the joints of the foot and ankle and the correction of the lateral talocalcaneal angle correlated with the degree of patient satisfaction and the functional rating of the club foot. Transfer of the anterior tibial tendon to the third cuneiform appeared to prevent relapse.

Diagnosis and management of compartmental syndromes.

Abstract: Patients at risk for compartmental syndromes challenge both the diagnostic and the therapeutic abilities of the physician. Suboptimum results may be due to delays in diagnosis and treatment, to incomplete surgical decompression, and to difficulties in the management of the limb after decompression. Although careful clinical assessment permits the diagnosis of a compartmental syndrome in most patients, we have found measurement of tissue pressure and direct nerve stimulation to be helpful for resolving ambiguous or equivocal cases. In our experience, the four-compartment parafibular approach to the leg and the ulnar approach to the volar compartments of the forearm provide efficient and complete decompression of potentially involved compartments. The skeletal stabilization of fractures associated with compartmental syndromes may facilitate management of the limb after surgical decompression.

Avascular necrosis following treatment of congenital dislocation of the hip.

Abstract: A review of 119 patients with congenital dislocation of the hip complicated by avascular necrosis, of whom fifty-one patients were skeletally mature, showed that damage to the physis was very common. Changes in the secondary ossification center (ossific nucleus) alone were found to be of very little value in predicting the nature of the development of the hip, while the change in the proximal femoral physis was the key to predicting residual deformity. The vascular disturbances were classified into four groups depending on the amount of damage involving the ossific nucleus and the physis during treatment of the dislocation. This classification was found to be accurate in predicting the natural history of avascular necrosis. The more severe forms of avascular necrosis were found to be most prevalent in those patients in whom treatment was begun between birth and the age of six months. We also found that preliminary traction and the use of general anesthesia reduced the incidence of the more severe form of avascular necrosis. The functional results found in the skeletally mature patients coincided with the types of vascular changes; the presence of avascular necrosis enhanced the development of arthritis, especially if residual dysplasia and subluxation also were present.

Osteochondral lesions of the talus.

Abstract: In a retrospective study of thirty-one ankles in twenty-nine patients with osteochondral lesions, we found that lateral lesions were associated with inversion or inversion-dorsiflexion trauma, were morphologically shallow, and were more likely to become displaced in the joint and to have persistent symptoms. Medial lesions were both traumatic and atraumatic in origin, morphologically deep, and less symptomatic. Using the classification system of Berndt and Harty, it appeared that Stage-I and Stage-II lesions should be treated non-operatively, regardless of location. Stage-III medial lesions should be treated non-operatively initially but if symptoms persist surgical excision and curettage are indicated. Stage-III lateral lesions and all Stage-IV lesions should be treated by early operation. Long-term results indicated that few lesions unite when treated non-operatively. Degenerative changes in the ankle joint, whether symptomatic or not, were common (50 per cent of the ankles) regardless of the type of treatment.

Biochemical studies on repair cartilage resurfacing experimental defects in the rabbit knee.

Abstract: Wounds penetrating articular cartilage to bone heal with cartilage described variably as either fibrous or hyaline. In the present study, such repair cartilage was induced in the rabbit for biochemical comparison with normal articular cartilage. The main collagen in the repair tissue after three weeks was type I. By six to eight weeks, type II had become predominant and continued to be enriched up to one year; but type I still persisted as a significant constituent of the repair tissue even after a year, so the repair cartilage never fully resembled normal articular cartilage. From radiochemical analysis, type II was determined to be the major collagen synthesized by the repair tissue after three to four weeks. After six months, the repair cartilage contained more collagen and less hexosamine than control cartilage, suggesting that the fibrous texture that often developed was due to a loss of proteoglycans rather than to a change in the type of collagen. Clinical Relevance: Procedures capable of inducing the differentiation of authentic articular cartilage to resurface degenerated human joints would be invaluable. Surgical methods, such as drilling through to subchondral bone, are often attempted. It is not known, however, whether the cartilage that forms is true articular cartilage or, for example, fibrocartilage. The present experimental study in rabbits compared the properties of such repair cartilage with those of normal articular cartilage.

Untreated ruptures of the anterior cruciate ligament. A follow-up study.

Abstract: Fifty patients (fifty-three knees) with surgically verified ruptures of the anterior cruciate ligament were evaluated at an average of ten years after injury. There was a high incidence of anterior laxity, rotatory instability, and meniscal tears at follow-up. The roentgenographic incidence of osteoarthritis at follow-up was low. Patients who had regained normal thigh circumference had better results than those with thigh atrophy. Although few of the patients felt that the knee was completely normal, 72 per cent of the patients returned to strenuous sports and 47 per cent felt that they had no restrictions because of the knee. This study of untreated ruptures may provide a baseline for evaluation of procedures to repair or reconstruct the anterior cruciate ligament.

Autogenous cortical bone grafts in the reconstruction of segmental skeletal defects.

Abstract: The results of using segmental cortical autogenous bone grafts to reconstruct defects created by resection of tumors were analyzed in forty patients. Thirty-three patients had dual grafts while seven had a single fibular graft. Dual grafts were used for major bones (humerus, femur, and tibia without fibula) while single grafts were used for the radius and for the tibia when the ipsilateral fibula was intact. Thirty patients had good or excellent results; seven, fair; and three, poor results. In twenty-five patients primary union was achieved within tweleve months and in two, in twenty months, while twelve patients required a second, supplementary cancellous graft at the site of non-union to obtain stability. One patient required removal of an infected graft and had a poor result. Stress fractures of the grafts occurred in eighteen of the forty patients after union had occurred. The stress fractures healed in fifteen of these patients: in six with no treatment (the fracture was identified retrospectively), in seven with external immobilization, and in two after bone-grafting of the ununited fracture. There were three persistent non-unions of stress fractures despite bone-grafting, internal fixation, and electrical stimulation, and these account for two of the three poor results. The length of the defect did not affect the incidence of non-union but it did affect the number of fatigue fractures. The shorter grafts (7.5 to twelve centimeters) were associated with a 33 per cent incidence of non-union (four non-unions of twelve grafts) while the longer grafts (twelve to twenty-five centimeters) had a 32 per cent rate of non-union (nine non-unions of twenty-eight grafts). The incidence of fatigue fractures in the longer grafts (58 per cent) was much greater than that in the shorter grafts (17 per cent). The grafts decreased in density during the first six months but gradually regained their mass and were generally comparable to normal cortical bone at two years. As the patients became functiona, most (55 per cent) of the the grafts became more dense than normal, some (34 per cent) remained the same, and a few (11 per cent) became less dense. Similarly, some (32 per cent) hypertrophied, most (58 per cent) remained the same size, and a few (9 per cent) atrophied. There was little morbidity (three of forty patients) associated with graft procurement. In twelve patients an additional graft was implanted experimentally, labeled with tetracycline, and subsequently removed at the time of a secondary procedure. These grafts were analyzed to determine if human grafts were repaired in the same fashion as grafts in experimental animals. The studies showed that human grafts are repaired in the same fashion, but that the sequence takes approximately twice as long as it does in the dog.

Fractures of the tibial tuberosity in adolescents.

Abstract: The cases of fourteen adolescents with fifteen physeal fractures of the tibial tuberosity were reviewed to more accurately define specific fracture patterns, to establish treatment for the different types, and to determine the incidence of complications. A modified classification scheme with a greater emphasis on intra-articular extension of the fracture and communution of the tuberosity was devised. Closed or open reduction, as necessary, gave satisfactory results. The primary indications for surgery were: (1) displacement of one or more fragments of the tuberosity anterosuperiorly, and (2) extension of the fracture through the proximal tibial ossification center into the knee joint, with disruption of the joint surface. There appears to be an increased incidence of pre-existing Osgood-Schlatter disease (ipsilateral and contralateral) in patients who have an acute tuberosity injury. Complications are rare. The theoretical possibility of the subsequent development of genu recurvatum appears unlikely, since most of these injuries occur when the physis of the tuberosity is undergoing normal closure.

Total hip arthroplasty in protrusio acetabuli of rheumatoid arthritis.

Abstract: Thirty-five total hip arthroplasties done in twenty-five patients with protrusio acetabuli secondary to rheumatoid arthritis were reviewed. There was an average follow-up of 4.3 years, with a range of three to seven years. The results were rated as excellent or good in 66 per cent, fair in 26 per cent, and poor in 8 per cent. Although 100 per cent demonstrated cementbone interface demarcation around the acetabular component, only 10 per cent showed progression of the line of demarcation to two millimeters and one had acetabular loosening with migration. Eight per cent showed femoral loosening or subsidence; 8 per cent, calcar resorption; and 6 per cent, a receding cortex with cystic changes. Twenty-three per cent had nonunion of the greater torchanter after trochanteric osteotomy. Type-III cement-bone interface demarcation was present around the acetabular component was positioned one centimeter superiorly or medially beyond the anatomical position, as estimated by the method described. In thirteen hips in which the acetabular component was positioned within five millimeters of the anatomical position, no Type-III demarcation was present. Better fixation and position of the acetabular component is achieved by the use of a bone graft or a special titanium perforated-sheet mesh, or both, or by an acetabular shell. The use of three wires improved trochanteric fixation.

A five to seven-year follow-up of unicondylar arthroplasty

Abstract: Thirty-two unicondylar knee replacements in thirty patients were done between 1972 and 1974. Ten patients were lost to follow-up because of death or other reasons. The remaining twenty-two knees (seventeen medial and five lateral compartments replaced) had a follow-up ranging from five to seven years, with an average of six years. Although the quality and result of these unicondylar arthroplasties were initially considered good, they have subsequently shown a marked deterioration. At the time of this report only one knee was rated as excellent; seven knees, as good; four knees, as fair; and ten knees, as poor. Seven knees (28 per cent) have been converted to a bicondylar prosthesis. The lateral replacements did much better than the medial replacements.

The intrinsic tensile behavior of the matrix of bovine articular cartilage and its variation with age

Abstract: To study the age dependence of the uniaxial tensile behavior of bovine articular cartilage, 216 specimens of articular cartilage from the patellofemoral joint were grouped into two age categories: those from joints with growth plates present (open physes) and those from joints without growth plates (no physes). We prepared standard, dumbbell-shaped test specimens from the three ultrastructural zones of the tissue: the superficial tangential zone, the middle zone, and the deep zone. As was done in the early works of Kempson et al. and of Woo et all., we prepared specimens whose long axes were either parallel or perpendicular to the axis of the local split line on the joint surface. In these tensile tests we observed a profound difference between the two age groups in terms of the variations in the tensile properties related to the depth below the surface. With increasing distance from the articular surface, the tensile strength and stiffness increased in the open-physis group and decreased in the no-physis group. Directional dependence of the tensile response was manifested by increased stiffness and strength of the samples oriented parallel to the split-line axis when compared with the samples oriented perpendicular to it. Distortion of the initially flat, straight-sided portion of the gauge section was observed in most of the 216 specimens immediately after the application of tensile strains. This effect casts serious doubts on all previous measurements of cross-sectional dimensional changes. At present, we believe that this distortion occurs because articular cartilage is an inhomogeneous, layered material. We also observed that cartilage exudes substantial amounts of its interstitial fluid when the applied tensile strain becomes large. These two effects create serious problems in assessing the true volumetric changes and the material properties of cartilage specimens during uniaxial tension experiments.

Complications and long-term results of ankle arthrodeses following trauma.

Abstract: A review of sixty patients who had undergone ankle fusion for post-traumatic arthritis revealed that thirty-five (58 per cent) had the procedure performed within the first year after injury. A total of forty-eight complications occurred in twenty-nine (48 per cent) of the patients. Frequent complication were infection (23 per cent), non-union (23 per cent), inadequate surgical alignment or early loss of position (15 per cent), malunion (12 per cent), and delayed union (7 per cent). The lateral transfibular approach had the highest incidence of complications, and a two-incision approach using the Charnley compression apparatus was the procedure with the fewest complications. Forty-one patients were followed for an average of 7.5 years after operation. Of these, thirty-four (83 per cent) were satisfied with the procedure. Examination of thirty of the forty-one patients at an average of 7.3 years after surgery revealed virtually no subtalar motion but motion of 13 degrees at Chopart's joint. With shoes, patients had a near-normal gait. The roentgenograms revealed a minimum amount of degenerative arthritis at Chopart's joint, which may worsen with time. Varus or valgus angulation of the hind part of the foot was associated with a greater degree of symptoms in the subtalar area as well as the middle of the foot. The neutral position in varus-valgus angulation as well as dorsiflexion-plantar flexion was the optimum position for both men and women. The results of the procedure did not deteriorate with time.

Current concepts review. The surgical staging of musculoskeletal sarcoma.

Abstract: The concept of staging malignant tumors arose in re sponse to the need for meaningful assessment of various methods of treatment in end-result studies. Its purpose was to ensure that lesions of comparable prognostic import were used to evaluate methods of management, so that one form of treatment was not inadvertently biased by inclu sion of a preponderance of favorable lesions while another method was adversely weighted on the basis of lesions with unfavorable predictors. The first staging system was developed for carcinoma of the cervix . The predictors were local invasion, regional metastases to lymph nodes, and distant metastases to other organs. In the ensuing years the importance of the concept of staging has been widely recognized and adopted internationally . Staging systems based on the natural history of the tumor have been de veloped for almost all histogenic types of various malig nant neoplasms. Conspicuous by its absence has been a staging system for sarcomas of connective-tissue deriva tion. An adequate surgical procedure has been recognized as the effective means of treating the majority of primary musculoskeletal sarcomas . Historically , amputation has been employed liberally. The recent demonstration that certain chemotherapeutic agents are capable of suppres sing or even eradicating microdisease8”° has encouraged an enthusiastic proliferation of innovative therapies for many of these highly malignant tumors 12,14,t8,Almost all of these therapies were designed to supplant or replace so-called standard surgical procedures, and have as their aim control of micrometastases and preservation of a functional extremity . The trend toward conservatiVe, limb-saving surgery (usually performed under an umbrella of adjunctive chemotherapy, irradiation, or immunoactive agents) presents the surgeon and the patient with a seem ingly attractive array of treatment options, the long-term effectiveness of which are unknown. Many of these extremity-preserving options include a surgical procedure that by itself is known to carry substantial risk of recur rence and hence an increased risk of metastasis. Although

The role of the ankle plantar flexors in normal walking.

Abstract: Gait studies were performed on five normal adult subjects before and after tibial-nerve block to assess the role of the ankle plantar-flexor muscles during walking. After the block all subjects were unable to transfer weight to the forward part of the foot on the blocked side, stance-phase ankle dorsiflexion and knee flexion were increased, and the duration of single-limb stance was shortened on the side of the block. In addition, quadriceps-muscle phasic activity was prolonged to compensate for loss of the normal contribution of the ankle plantar-flexor muscles to knee stability, and there was an average reduction of step length on the opposite side of sixteen centimeters as well as a 23 per cent average reduction in walking velocity. In the absence of the normal plantar-flexor phasic activity, the horizontal and vertical velocities increased during part of the gait cycle, indicating an exaggerated fall of the center of mass. The excessive work output that was demonstrated after tibial-nerve block in each subject is explained by the exaggerated fall of the center of mass, necessitating excessive energy expenditure twlift the center of mass through the sound limb. The role of the ankle plantar flexors during gait is to contribute to knee stability, provide ankle stability, restrain the forward rotation of the tibia on the talus during stance phase, and conserve energy by minimizing vertical oscillation of the whole-body center of mass. To accomplish these functions, the plantar flexors first provide active resistance to forward rotation of the tibia by lengthening (eccentric muscle reaction) while providing increasing resistance that eventually checks further forward rotation of the tibia. They then progressively shorten (concentric muscle reaction), reducing ankle dorsiflexion, adjusting limb * Supported in part by a grant from the National Institute of Child Health and Human Development, No. 5 ROL HDO 8520, and in part by a grant from the Muscular Dystrophy Association of America. t Division of Orthopedic Surgery and Rehabilitation, University of California, San Diego, California 92093. $ Children's Hos ital and Health Center, 8001 Frost Street, San Diego, California 921%. length, and restraining the drop of the whole-body center of mass. They do not propel the body forward although, paradoxically, maximum step length is not possible without the essential stabilizing effect of the plantar flexors. CLINICAL RELEVANCE: Identification of the individual components of the calcaneal limp provides the necessary foundation for clinical recognition of this disorder. The single most important clinical observation is that ankle dorsiflexion progressively increases during single-limb stance until opposite foot-strike occurs, and the ipsilateral heel does not leave the floor until weight is transferred to the opposite foot. Measurement of the significant gait variables affected by weakness of the triceps surae indicates that the disturbance of walking is profound, despite all appearances to the contrary. It seems quite obvious that measurements must be made before and after treatment if orthotic and surgical corrective measures are to be assessed accurately. Kinesiology has progressed from the study of anatomy and function, as exemplified by the exquisite sketches of Leonardo da Vinci, to a scientific discipline drawing heavily on anatomy, physiology, and bioengineering to study human motion. The newcomer of these three disciplines, bioengineering, brings measurement techniques that facilitate the analysis of gait dynamics. New techniques provide dynamic measurements that necessitate constant reassessment of previously held concepts of muscle function. Several authors have described the role of the ankle plantar flexors during normal gait. According to Houtz and Walsh, the soleus, tibialis posterior, and peroneus brevis muscles stabilize the ankle by adjusting the tibia on the tarsus. Sutherland l2 emphasized an important knee-ankle stability linkage, noting that the ankle plantar flexors decelerate the stance-phase forward rotation of the tibia on the talus, providing selective, more rapid extension at the knee joint. While some authors agreed that there is a push-off or thrust upward through the leg occurring after hee l -~ f f l .~ .~ , the entire push-off concept was questioned 3 54 THE JOURNAL OF BONE AND JOINT SURGERY ROLE OF THE ANKLE PLANTAR FLEXORS IN NORMAL WALKING by o t h e r ~ ~ , ~ , ~ , ' ~ . Perry advised dropping the term push-off and postulated that the late floor-reaction peak is the result of leverage exerted by body alignment rather than an active downward thrust. Mann et al. concluded that the plantar flexors do not actively push or propel the body forward, but control the forward propulsive momentum, making it possible for the body to move farther forward from its base of support. This explanation, while denying the validity of the push-off theory, acknowledges the contribution of the plantar flexors to increased step length. The implication is that increased step length is not produced by the ankle plantar flexors but cannot be achieved without their contribution. At this time there seems to be little dispute over the decelerative or stabilizing function of the calf muscles during forward movement of the tibia on the talus, but controversy still surrounds their accelerative function during heel-off. Part of the problem, we believe, lies in the models studied. While it is not too difficult to study the function of normal muscles during gait, it is very difficult to separate out the contributions of individual muscles, gravity, and kinetic energy in any analysis of gait. When attempts are made to draw conclusions from patients with paralysis of the plantar flexors, additional factors are introduced. For example, motor paralysis from poliomyelitis or myelodysplasia frequently produces alteration of the length and weight of the shank segment and of the shape, weight, and function of the foot. Vertical alignment of the calcaneus in the foot with a calcaneus deformity changes the axis of the subtalar joint. Constant stress on the posterior soft tissues of the ankle produces elongation of the capsule, tendons, and ligaments. Also, compensatory muscle activity partially masks the primary gait deficit. The study of patients with below-the-knee prostheses to determine the function of the ankle plantar-flexor muscles has similar objections. In addition to the differences in the weight of the shank, the suspension of the prosthesis may affect knee movements. Proprioception and sensation are absent and motion of the ankle joint is usually excluded by prosthetic design. These considerations led us to carry out an experimental study to assess the normal contribution of the ankle plantar-flexor muscles during gait by blocking the tibial nerve. Tibial-nerve block produces paralysis of the gastrocnemius, soleus, plantaris, tibialis posterior, flexor digitorum longus, and flexor hallucis longus muscles. The only plantar-flexor muscles to escape the block are the peroneus longus and peroneus brevis. Since their potential flexion moment is small\", paralysis is nearly complete and a calcaneal gait is produced. The establishment of compensatory gait mechanisms is minimized by immediate resumption of gait following the block. The walking pattern was studied before and after the tibial nerve blocks, so that the exact differences produced by ankle plantar-flexor paralysis could be described. In these studies, we were interested primarily in the action of these muscles in the sagittal plane. Methods

Acute tears of the posterior cruciate ligament. Results of operative treatment.

Abstract: The posterior cruciate ligament, situated near the center of the knee, functions as the basic stabilizer and is located close to the axis of motion. We diagnosed and repaired thirty-two consecutive acute tears of the posterior cruciate ligament associated with tears of medial or lateral-compartment ligaments, or of both. Of the twenty-nine knees that we could evaluate, twenty-three demonstrated a 2+ to 3+ positive abduction or adduction stress test done in maximum extension and a positive anterior drawer test done in maximum internal rotation, while only nine had a definitely positive posterior drawer test. In all knees we repaired the tears, using the medial meniscus as a graft in nine knees in which the repair of the posterior cruciate ligament did not produce immediate adequate stability at operation. Five to sixteen years after operation, twenty of these twenty-nine knees were available for evaluation. The objective results were good in thirteen, fair in four, and poor in three.

Carpal-tunnel syndrome. Results of a prospective trial of steroid injection and splinting.

Abstract: In order to define the role of steroid injection and splinting as a method of treatment of carpal-tunnel syndrome, a prospective study was performed on fifty hands in forty-one consecutive patients. All hands were treated with a single injection and three weeks of splinting. Follow-up ranged from a minimum of six months to a maximum of twenty-six months, with a mean of eighteen months. All hands had characteristic symptoms of median-nerve compression at the wrist and increased distal median motor latencies. Eleven (22 percent) of fifty hands were completely free of symptoms at the end of the follow-up period. Hands that initially had mild symptoms and findings of less than one year's duration, normal sensibility, normal thenar strength and mass, and one to two-millisecond prolongations of either distal median motor or sensory latencies had the most satisfactory responses to injections and splinting. Hands with severe symptoms of more than one year's duration and findings of atrophy, weakness, and distal motor latencies of more than six milliseconds or absent sensory responses had the poorest response to injections and experienced a high rate of relapse.

Surgical treatment of transchondral talar-dome fractures (osteochondritis dissecans). Long-term follow-up.

Abstract: Experience with forty-nine patients with surgically treated transchondral fractures of the talar dome seen between 1957 and 1977 at our institution has indicated that surgical treatment yields a good long-term result Long-term results in twenty-five patients with sufficiently long follow-up (average, sixty-five months) were recorded Ninety-two per cent of the patients had had a history of severe ankle sprain or fracture and many had had chronic symptoms before the definitive diagnosis was made The surgical treatment consisted of drilling and curettage followed by non-weight-bearing and early range-of-motion exercises Twenty-two patients had good or excellent results, two had fair results, and one had a poor result In eleven patients followed for five to eighteen years, no deterioration in functional capacity was noted; however, improvement in the postoperative status was noted for as long as eighteen months Even when it was performed for a chronic lesion the operation gave a high percentage of good results, and the long-term results did not differ appreciably from the results eighteen months postoperatively No other reports were found concerning long-term follow-up of this lesion

Periarticular heterotopic ossification in head-injured adults. Incidence and location.

Abstract: The records of 496 adult patients who sustained severe injuries to the head were reviewed retrospectively in order to reveal the incidence and location of heterotopic ossification. All traumatized joints were excluded from the study. Clinically significant heterotopic bone causing pain and a decrease in the range of motion of the adjacent joint was identified in 100 joints in fifty-seven patients (11 per cent). All fifty-seven patients had some residual spasticity, although the spasticity was not always present about the involved joint. Twenty-seven patients had monoarticular involvement while thirty patients had involvement of more than one joint. Forty-four hips, twenty-seven shoulders, twenty-six elbows, and three knees had heterotopic ossification. Complete ankylosis (16 per cent of all joints) developed in eight elbows, six hips, and two shoulders.

Morphological, immunochemical, and biochemical study of rabbit achilles tendon at various ages.

Abstract: With aging, rabbit tendon tissue undergoes a series of morphological and biochemical changes which involve both the cells and the extrace-lular matrix. The extracellular matrix increases in volume, causing a relative decrease of the number of cells per unit of tissue surface. The tenoblasts become longer and more slender, while their cytoplasmic processes increase in number and become thinner and more elongated, forming a dense network. In addition, tendon cells show a marked decrease in the intracytoplasmic organelles responsible for protein synthesis, while their intracellular content of contractile proteins does not change. With aging collagen fibers increase in diameter and vary more in thickness. These morphological changes correspond to biochemical changes that include an increase in collagen, a decrease in mucopolysaccharides, and a decrease in water content. During aging parallel changes occur in the elastic fibers, which decrease in number and show structural alterations. CLINICAL RELEVANCE: Ultrastructural and biochemical studies of tendon diseases need a normal comparison. Out ultrastructural and biochemical findings in aging tendon may be useful in that regard. The presence of actin and myosin in tendon cells could be related to some aspects of tendon physiology and pathology.

An analysis of femoral component stem design in total hip arthroplasty.

Abstract: A comparative study of the various aspects of the design of the femoral components of total hip replacements was done using three-dimensional finite-element stress analysis. The aspects of deisgn that were considered included: length, cross-sectional size, and material properties of the stem; presence or absence of a medial collar; and material properties of the cement. We found that increasing the length of the stem generally increased the stress present in the stem while decreasing the stress present in the cement. Increasing the cross-sectional size of the stem decreased the stress in both the stem and the cement. Decreasing the modulus of elasticity of the stem material decreased the stress in the stem but increased the stress in the cement. Increasing the modulus of elasticity of the cement decreased the stress in the stem and increased the stress in the cement. Contact of the collar of a femoral prosthesis with the calcar femorale increased the longitudinal component of stress within the region of the calcar femorale. Clinical relevance: The mechanical longevity of a total joint reconstruction is related to the stress distribution throughout the prosthesis, cement, and bone. The stress distribution is related to a number of factors, including the design of the prosthetic components (for example, stem size, stem length, stem modulus of elasticity, and cement modulus of elasticity). Reducing the stresses in prosthetic components to minimize the risk of failure can be accomplished only through systematic analysis of all components of the reconstruction.

Efficacy of various forms of fixation of transverse fractures of the patella.

Abstract: To determine whether any of the commonly used wiring techniques are rigid enough to allow early motion in the treatment of transverse fracture of the patella, the patellae of twenty-five fresh cadaver knees were fractured transversely and fixed using the following techniques: circumferential wiring, tension-band wiring, Magnusson wiring, and a modification of tension-band wiring. The knees were mounted in a machine capable of measuring quadriceps force, flexion angle, and fracture separation simultaneously. The knees were extended from 90 to zero degrees by applying tension to the quadriceps tendon with the force of gravity as the only resistance, and separation of the fracture fragments was measured first with the retinaculum unrepaired and then again with the retinaculum repaired. Separation of the fracture fragments was much less with the Magnusson wiring and modified tension-band wiring than with circumferential wiring or standard tension-band wiring. The retinacular repair was found to contribute to stability; however, this seemed most important in the less rigid repairs. We concluded that if early motion is to be used in treating transverse fractures of the patella, techniques in which the wire is anchored directly in bone should be used and the retinaculum should be repaired.

Total elbow replacement

Abstract: Thirty-one patients who underwent thirty-six total elbow replacements between 1974 and 1977 were followed for a minimum of two years with an average of 3.7 years. A scoring system was used to quantitate results. Patients with rheumatoid arthritis and functional disability primarily related to pain benefited most from the operation. Patients with post-traumatic arthritis and disability secondary to loss of motion benefited least. The over-all complication rate was 53 per cent and the reoperation rate was 22 percent. However, only one-fourth of the complications adversely affected the final outcome. Total elbow replacement can give good results in carefully selected patients.

Treatment of idiopathic scoliosis in the Milwaukee brace.

Abstract: The results of treatment of idiopathic scoliosis with a Milwaukee brace were studied in 133 patients (127 girls and six boys) whose ages ranged from eight years and five months to sixteen years and two months at the beginning of treatment. These 133 patients had 192 separate curves (119 right thoracic, thirty-nine high lumbar, twelve thoracolumbar, and twenty-two high left thoracic). Of these patients, seventy-four with 109 curves were followed for five years or more after the brace was discontinued (average, eight years; range, five to thirteen years); twenty-nine patients were treated surgically because of a poor response to the brace or progression of the curve; and thirty patients were lost to follow-up. More than 80 per cent of the seventy-four patients followed for five years or more showed some increase of their curves after the brace was discontinued. The average correction at follow-up compared with the original curve was 2 degrees for thoracic curves (range, -18 to 24 degrees) and 4 degrees for the thoracolumbar and lumbar curves (range, -11 to 17 degrees). The brace was more effective for curves of less than 40 degrees. More than one-third of the patients with curves of 40 degrees or more eventually required surgical treatment. Age, curve pattern, and status of the iliac and ring epiphyses did not correlate withe response to brace treatment. The best guideline for prediction of the results of brace treatment was the response of the curve to the brace, especially during the first year of treatment. If the curve is reduced in the brace to less than 50 per cent of its initial measurement, there is a good chance of obtaining significant permanent correction.