Showing papers in "Journal of Arthroplasty in 1999"

Morphologic study of the glenoid in primary glenohumeral osteoarthritis.

Abstract: We studied the natural course and the possibility of making a prognostic classification of glenoid morphology in primary glenohumeral osteoarthritis (GHOA). For this purpose, serial computed tomography scans of 113 osteoarthritic shoulders were reviewed. The position of the humeral head with respect to the glenoid seems to be an important predictor of the glenoid morphologic evolution. Three main glenoid types were defined: Type A, Type B, Type C. Type A (59%) was marked by a well-centered humeral head and a balanced distribution of strengths against the surface of the glenoid. The symmetric erosion was explained by the absence of subluxation. In Type B (32%), the posterior subluxation of the humeral head was responsible for the asymmetric load against the glenoid and was implicated in the development of primary GHOA, particularly the exaggerated posterior wear pattern. Type C (9%) was defined by a glenoid retroversion of more than 25 degrees, regardless of erosion; retroversion was primarily of dysplastic origin and explained the early event of osteoarthritis. In primary GHOA, this classification of the glenoid can discriminate retroversion between posterior erosion and dysplasia.

Implant fixation by bone ingrowth

Abstract: The term osseointegration referred originally to an intimate contact of bone tissue with the surface of a titanium implant; the term bone ingrowth refers to bone formation within an irregular (beads, wire mesh, casting voids, cut grooves) surface of an implant. The section dealing with the historical background describes the development of macroporous, microporous, and textured surfaces with an emphasis on the evolution of porous and textured metal surfaces. The principal requirements for osseointegration and bone ingrowth are systematically reviewed as follows: i) the physiology of osseointegration and bone ingrowth, including biomaterial biocompatibility with respect to cellular and matrix response at the interface; ii) the implant surface geometry characteristics; iii) implant micromotion and fixation modes; and iv) the implant-bone interface distances. Based on current methods of bone ingrowth assessment, this article comparatively reviews and discusses the results of experimental studies with the objective of determining local and systemic factors that enhance bone ingrowth fixation.

Tissue response to porous tantalum acetabular cups: a canine model.

Abstract: This study evaluated the osseous tissue response to a noncemented metal-backed acetabular component made of a new porous tantalum biomaterial. Eleven dogs with bilateral total hip arthroplasties (22 acetabular implants) were studied for a period of 6 months. Thin section histology, high-resolution radiography, and backscattered scanning electron microscopy revealed that all 22 implants had stable bone-implant interfaces. Regions of bone ingrowth were present in all histologic sections. The depth of bone ingrowth varied from 0.2 mm to the maximal limit of 2 mm. Analyzing contiguous regions of interest across the full bone-implant interface, the mean bone ingrowth for all sections was 16.8% +/- 5.7%. In the peripheral regions of the cup where bone-implant contact was most consistent, bone ingrowth averaged 25.1% +/- 10.1%. The data indicate that the porous tantalum material is effective for biologic fixation in the dog and may provide a suitable alternative to other porous materials used in acetabular cup design.

Risk factors for dislocation during the first 3 months after primary total hip replacement.

Abstract: The prevalence of dislocation of a total hip replacement during the first 3 postoperative months was determined for a series of 315 patients who underwent a unilateral primary total hip operation. All operations were performed by 1 surgeon using a standardized posterior approach with a complete capsulectomy. All of the patients had a femoral component made by 1 manufacturer that had the same 28-mm modular head, the same femoral neck diameter, and the same offset for each size implant. One cementless acetabular component was used for all patients. All of the patients followed the same postoperative rehabilitation program. Of 315 patients, 14 sustained a dislocation, resulting in a prevalence of 4%. There were 13 posterior dislocations and 1 anterior dislocation. Because the surgeon, the surgical approach, the femoral component design, and the rehabilitation protocol were identical for all of these patients, the only variables that could affect the risk of dislocation were the size of the acetabular component and the femoral neck length, the type of fixation of the femoral component, the orientation of the acetabular component, and the characteristics of each patient. The patient characteristics that were studied included age; gender; height; weight; preoperative diagnosis; and a category termed cerebral dysfunction, which included a state of confusion during the hospital stay, a prior history of excessive alcohol consumption, or both of these conditions. Statistical analysis demonstrated 1 variable that was associated with a higher dislocation rate, the presence of cerebral dysfunction. There was a trend toward increased age as a risk factor. None of the other patient or component variables were found to be significant risk factors.

Results of a method of leg-length equalization for patients undergoing primary total hip replacement.

Abstract: The postoperative leg-length discrepancy was determined radiographically for a consecutive series of 351 patients (408 hips) who underwent bilateral or unilateral primary total hip replacement using a single method of leg-length equalization by preoperative planning with overlay templates. The method of equalization was performed by a measurement of the femoral head and neck segment to be resected from a reference point at the superior aspect of the dislocated femoral head. The amount of femoral bone resected was determined preoperatively by determining the dimensions of the acetabular component thickness and the femoral component head and neck height that would be replacing this resected bone and adjusting this distance for any preexisting leg-length discrepancy. Using this leg-length equalization method, the length of the modular femoral head nec was chosen preoperatively, rather than using soft tissue tension across the prosthetic hip joint to determine whether the leg lengths were equal. Postoperative leg lengths were determined radiologically from a measurement from the acetabular teardrop to the lesser trochanter. Ninety-seven percent of the patients had a postoperative leg-length discrepancy that was less than 1 cm, and 86% had a leg-length difference that was 6 mm ( 1 4 inch) or less. The average postoperative discrepancy for these 351 patients was 1 mm.

In vivo determination of condylar lift-off and screw-home in a mobile-bearing total knee arthroplasty.

Abstract: Twenty subjects implanted with the low-contact stress (LCS) cruciate-sacrificing, mobile-bearing total knee arthroplasty underwent dynamic videofluoroscopy during in vivo weight-bearing conditions using a 3-dimensional computer-aided design (CAD) interactive modeling method. Ninety percent of the subjects demonstrated significant lift-off during stance phase of gait. Condylar lift-off was present at both the medial and the lateral condyles. The maximal medial lift-off was 2.12 mm, whereas the greatest lateral lift-off was 3.53 mm. The maximal positive screw-home was 9.6 degrees, whereas the maximal negative or reverse screw-home was 6.2 degrees. The average screw-home rotation was positive 0.5 degrees. In 50% of patients, medial condylar translation was unexpectedly greater than lateral condylar motion. Condylar lift-off and screw-home motion are significant kinematic functions in this rotationally unconstrained total condylar knee arthroplasty.

The effect of acetabular cup orientations on limiting hip rotation.

Abstract: The orientation of the acetabular cup and position of lip augmentation (if present) may improve postoperative total hip replacement stability by decreasing dislocation caused by hip prosthesis impingement during rotation To determine how these cup parameters affect dislocation, the range and amount of rotation for two standard femoral components was determined in a Sawbones hemipelvis model The parameters that allowed for maximal range of rotation were a cup angle of inclination between 35° and 45° and cup anteversion between 0° and 10° Cup anteversion angles greater than 20° and cup angles of inclination greater than 45° significantly limited internal and external rotation, particularly for hip flexion greater than 60° The position of the cup lip augmentation did not affect the amount of rotation except when the hip was flexed and the lip superiorly oriented Although there are currently devices to facilitate a particular cup position, hip stem type and orientation are other important factors affecting range of rotation that must be considered

The use of vancomycin and tobramycin in acrylic bone cement: biomechanical effects and elution kinetics for use in joint arthroplasty.

Abstract: We examined the effects of vancomycin on the compressive strength and fatigue life of bone cement and the pharmacokinetics and antimicrobial activity against methicillin-resistant Staphylococcus aureus of vancomycin eluted from bone cement, both alone and in combination with tobramycin. Two cements, Palacos and Simplex, were tested. Three antibiotic preparations were tested: lyophilized vancomycin (vancomycin-L), vancomycin powder (vancomycin-P), and tobramycin powder (Lilly, Indianapolis, IN). Although antibiotics did not significantly affect compressive strength, the fatigue life of bone cement was significantly decreased with vancomycin. Thus, fatigue testing revealed effects on cement strength not apparent by compression testing. Vancomycin-P had a substantially less detrimental effect on fatigue strength than vancomycin-L. Vancomycin-P elutes less efficiently than tobramycin. Although relatively little vancomycin-P eluted from bone cement, it retained biologic activity.

Total Hip Arthroplasty for Osteonecrosis Matched-Pair Analysis of 188 Hips With Long-Term Follow-Up

Abstract: A matched comparison was made between total hip arthroplasties done for osteonecrosis and those done for osteoarthritis. Patients were matched for age, sex, surgical approach, prosthesis, and surgeon. All received cemented Charnley replacements and had minimal follow-up of 10 years. There were 118 women and 70 men with a mean age of 58 years. Thirty-five patients were younger than 50. The mean follow-up was 17.8 years (range, 10 to 25.4 years). Revision rates for osteonecrosis and osteoarthritis were 18% and 19% (not significant). The mechanical failure rate (revision for loosening plus radiographic loosening) was greater, but not significantly so, in the osteonecrosis group. In patients younger than 50 years, the revision rate in osteonecrosis (50%) was significantly higher than that in any other group. Similarly, the mechanical failure rate in osteonecrosis was significantly greater in the patients younger than 50. Radiographic femoral loosening was greater in osteonecrosis at all follow-up intervals, and dislocations occurred more frequently in the osteonecrosis group than in the osteoarthritis group. Results of arthroplasty in both groups were comparable in patients over 50 years of age, although patients with osteonecrosis had an increased rate of dislocation. Patients with osteonecrosis who are younger than 50 years have a significantly higher rate of mechanical failure than those with osteoarthritis who are younger than 50 years. Cemented total hip arthroplasty should be recommended in this group with caution if at all.

Plasticity-induced damage layer is a precursor to wear in radiation-cross-linked UHMWPE acetabular components for total hip replacement

Abstract: The mechanism for the improved wear resistance of cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) remains unclear. This study investigated the effect of cross-linking achieved by gamma irradiation in nitrogen on the tribologic, mechanical, and morphologic properties of UHMWPE. The goal of this study was to relate UHMWPE properties to the wear mechanism in acetabular-bearing inserts. Wear simulation of acetabular liners was followed by detailed characterization of the mechanical behavior and crystalline morphology at the articulating surface. The wear rate was determined to be directly related to the ductility, toughness, and strain-hardening behavior of the UHMWPE. The concept of a plasticity-induced damage layer is introduced to explain the near-surface orientation of the crystalline lamellae observed in the wear-tested acetabular liners. Cross-linking reduces abrasive wear of acetabular components by substantially reducing--but not eliminating--the plasticity-induced damage layer that precedes abrasive wear.

Hydroxyapatite coating versus cemented fixation of the tibial component in total knee arthroplasty: Prospective randomized comparison of hydroxyapatite-coated and cemented tibial components with 5-year follow-up using radiostereometry

Abstract: Fifty-three consecutive patients (57 knees; mean age, 69 years) entered a prospective randomized study to compare the fixation of hydroxyapatite (HA)-coated (29 knees) with cemented (28 knees) tibial components in the Tricon II total knee arthroplasty. The quality of the fixation during 5 years postoperatively was evaluated with radiostereometric analysis (RSA). Three HA-coated implants were revised: 2 owing to infection, and 1 owing to early delamination of the coating and clinical loosening. Eight patients (9 knees) died, 1 patient sustained a stroke, and 1 patient refused investigations after 1 year. In the 40 patients (19 HA-coated, 21 cemented) remaining at 5 years, the magnitude of the micromotion between the HA-coated and cemented groups did not differ. The HA-coated implants displayed most of the migration within the initial 3 months then stabilized, whereas the cemented implants showed an initially lower, but over time continuously increasing migration. Between 1 and 2 years, 4 of 24 HA-coated and 10 of 23 cemented implants migrated >0.2 mm and were categorized unstable, which has been shown to have a prognostic value as regards future aseptic loosening. Progressive radiolucent lines developed in 2 cemented knees, which both were categorized unstable. If HA-coated implants can sustain the forces that threaten the fixation in the early period after implantation, a strong and enduring fixation may be obtained.

Primary total hip arthroplasty with a cementless porous-coated anatomic total hip prosthesis: 10- to 12-year results of prospective and consecutive series.

Abstract: We performed a prospective study in 108 consecutive patients (116 hips) who were followed for a minimum of 10 years (10-12 years) after primary total hip arthroplasty using an uncemented porous-coated anatomic (PCA) hip prosthesis. The average age of the patients at operation was 48.4 years (range, 19-85 years), and the diagnosis was avascular necrosis of the femoral head in 46 hips, neglected femoral neck fracture in 27, osteoarthrosis secondary to childhood pyogenic arthritis in 24, childhood tuberculous arthritis in 5, and miscellaneous in 14. The average preoperative Harris Hip Score was 55 points, which improved to 87 points at 11 years. Seventy-five hips (65%) were excellent, 11 (9%) were good, and 30 (39%) were poor. The overall rate of revision was 15% (17 of 116 hips). The rate of revision of the femoral component was 11% (13 of 116 hips), and the rate of revision of the acetabular component was 15% (17 of 116 hips). The prevalence of thigh pain was 28% at 11 years. The increase in the incidence of aseptic loosening of the femoral component was found to explain the high incidence of severe thigh pain at 11 years' follow-up. At 11 years, there was femoral osteolysis in 69 hips (59%) and acetabular osteolysis in 65 hips (56%). At 6 years, 20 hips (17%) showed definite wear of the polyethylene liner. At 11 years, 81 hips (70%) showed definite wear of the polyethylene liner. Because the complication rate of the PCA hip prosthesis with respect to loosening, osteolysis, and excessive wear in the polyethylene liner is high, we abandoned the use of this implant.

The in vitro elution characteristics of antibiotic-loaded CMW and Palacos-R bone cements

Abstract: An in vitro study was carried out comparing the elution characteristics of Palacos-R and CMW acrylic cements. Three groups of 6 antibiotic-loaded cement disks were prepared, incorporating 1.0 g vancomycin and 2.4 g tobramycin per 40 g packet of cement. Palacos-R bone cement was used for group 1, CMW 1 for group 2, and CMW 3 for group 3. The disks were placed in saline baths for 9 weeks. The baths were periodically sampled and elution rates calculated. CMW 1 released 24% less tobramycin and 36% less vancomycin than Palacos-R over the total study period (P < .05). CMW 3 released 34% less tobramycin and 38% less vancomycin than Palacos-R (P < .05). There was no significant difference in antibiotic release between CMW 1 and CMW 3. The in vitro elution characteristics of Palacos-R are superior to CMW.

Acetabular fracture associated with cementless acetabular component insertion : a report of 13 cases

Abstract: Acetabular fracture during insertion of a cementless acetabular component occurred in 13 patients. The preoperative diagnosis was osteoarthritis in 6 patients, rheumatoid arthritis in 2 patients, avascular necrosis in 3 patients, hip fracture nonunion in 1 patient, and developmental dysplasia of the hip in 1 patient. Several different components were used; however, the acetabulum was underreamed by 1 to 3 mm in all cases. The acetabular fracture was identified in 9 of 13 cases intraoperatively. The fracture was identified on postoperative radiographs for the other 4 cases. Fractures were treated by a variety of means, including the addition of augmentation screws in or around the cup, use of autograft bone at the fracture site, modified postoperative weight-bearing status, and immobilization. In 2 cases, the socket needed to be revised after it progressively migrated and failed. One patient had cup migration, and another had a radiolucent line about the cup but was not symptomatic enough to require revision. In 3 of these 4 cases, the fracture was not identified intraoperatively. Underreaming of the acetabulum and use of an oversized acetabular component has been recommended to improve the initial stability of the acetabular component during total hip arthroplasty. Impaction of an oversized component requires bone to undergo plastic deformation if the cup is to be fully seated. Theoretically, this technique provides improved component stability with enhanced osseous ingrowth into the cup. The 13 cases reported in this study demonstrate that acetabular fracture is a complication that may occur in association with uncemented hip arthroplasty, particularly if oversized components are used. The importance of recognizing acetabular fractures intraoperatively and the need to institute appropriate treatment to ensure a stable acetabular component is emphasized. In patients with osteoporotic bone, line-to-line reaming with use of a cementless acetabular component or insertion of a cemented socket may be considered to avoid this significant complication.

The Insall-Burstein total knee replacement in osteoarthritis: a 10-year minimum follow-up.

Abstract: A total of 99 Insall-Burstein posterior stabilized (IBPS) knee replacements were implanted in 86 osteoarthritic patients. We reviewed 60 knees with a 10- to 15-year follow-up. Using the Knee Society score, 35 knees (58%) were excellent, 15 (25%) good, 4 (7%) fair, and 6 (10%) poor. Flexion at follow-up was 106 degrees on average. Moderate patellofemoral crepitation was present in 5 knees (9%), and 11 knee required excision of a synovial nodule proximal to the patella. Radiographic analysis showed 5 osteolytic lesions (8%) around well-fixed tibial and femoral components and minimal (1 mm) narrowing of the medial polyethylene thickness in 7 knees (12%). There were 6 (10%) failures requiring reoperation because of aseptic loosening (4 knees), deep infection (1 knee), and recurrent patellar dislocation (1 knee). Survivorship analysis using revision as the endpoint showed a cumulative success rate of 92% at 10 years. In this study, the IBPS knee has shown good long-term results with low rates of aseptic loosening and no failures attributable to polyethylene wear.

Flexion-extension joint gap changes after lateral structure release for valgus deformity correction in total knee arthroplasty: a cadaveric study.

Abstract: At the time of total knee arthroplasty, the surgeon generally corrects excessive valgus knee alignment to anatomic valgus through release of lateral supporting structures. This study used a cadaveric model to i) study the amount of correction achieved with each release step in 2 sequences of lateral release, ii) compare the amount of release in extension versus flexion, and iii) measure any associated rotational changes of the tibia. Six fresh-frozen cadaveric knees were used to test the amount of change into varus after sectioning the iliotibial band (ITB), the popliteus tendon (Pop), the lateral collateral ligament (LCL), and the tendon of the lateral head of the gastrocnemius (LG). This sequence was then compared with a second sequence in another 6 cadavers as follows: LCL, Pop, ITB, and LG. The amount of valgus correction was tested in 90 degrees, 45 degrees flexion, and full extension. At each flexion angle, the corresponding releases were assessed with the tibia oriented vertically under its own weight, under tibial distraction with equal support from the lateral and medial soft tissues, and under a maximal varus deforming stress. Results showed that complete lateral structure release provides limited correction into a varus direction with a balanced distracted soft tissue gap or extension space (8.9 degrees with the LG released), and the lateral aspect of the flexion gap opens more than the extension gap (8.9 degrees compared with 18.1 degrees in flexion). Early LCL release provided a more uniform release of the joint gap, and rotational changes were variable, tending toward external rotation of the tibia (6.0 degrees in full extension with release of the LCL). We suggest that when severe valgus deformities are present, the LCL should be considered first for release and the Pop and ITB be used to grade the release.

An in vivo analysis of the effectiveness of the osteoarthritic knee brace during heel-strike of gait.

Abstract: The objective of this study was to analyze the effects of off-loading knee braces in patients diagnosed with symptomatic unicompartmental osteoarthritis. Under fluoroscopic surveillance, 15 patients were asked to perform normal gait on a treadmill. Each patient was asked initially to walk without using a knee brace and then to walk while wearing a brace. The fluoroscopic images of the patients at heel-strike were downloaded to a workstation computer. Condylar separation angle of the knee joint and the distances from the medial and lateral femoral condyles to the tibial plateau (condylar separation) were measured. Twelve of 15 patients (80%) reported relief of pain and demonstrated condylar separation of the degenerative compartment with the use of the off-loading brace. The 3 patients who did not demonstrate condylar separation were obese, making accurate brace fitting difficult. The average change in condylar separation and condylar separation angle was 1.2 mm (range, 0.0-4.5 mm) and 2.2 degrees (range, 0.0 degrees-7.8 degrees). This study demonstrated that condylar separation of a degenerative knee compartment can be achieved with off-loading braces with subsequent subjective relief of knee pain.

One- or two-stage bilateral total hip replacement.

Abstract: It is not clear whether bilateral hip replacement should be done in 1 or 2 stages. The total number of total hip replacements (THRs) done in our center between 1989 and 1995 was approximately 4,000. The number of hips that were bilateral was 404, or 9% of the total number of THRs performed during this time period. Of these bilateral hip replacements, 190 (95 patients) were done as a 1-stage procedure, whereas 214 (107 patients) were done in 2 stages with 2 to 24 months in between the operations. In contrast to previous studies, there were no significant preoperative differences between the 2 groups of patients having 1-stage or 2-stage THRs, and, in particular, the comorbidity assessed by the American Society of Anesthesiologists (ASA) grade was not significantly different. Our results demonstrate that, in our patient population, bilateral THR was equally safe whether performed as a 1-stage or 2-stage procedure. This was the case in the low-risk (ASA 1 and 2) and high-risk (ASA 3 and 4) patient subgroups. One-stage bilateral THR is cheaper and involves less time in the hospital.

Cytokine response of human macrophage-like cells after contact with polyethylene and pure titanium particles.

Abstract: The aim of this study was to establish a human macrophage cell culture system to examine the effect of polyethylene (PE) and titanium particles on cytokine release by macrophage-like cells (MLC) and to quantify this response with respect to the nature and concentration of particles. Human monocytic leukemia cells were differentiated under standard conditions with vitamin D3 and granulocyte macrophage-colony-stimulating factor. Cells were characterized by fluorescence-activated cell-sorter Scan of CD 14 expression analysis as well as a phagocytosis test exploiting fluorescence-labeled particles of bacteria] walls. To achieve a relevant contact between the floating PE particles (approximately 1 microm in size) and MLC, a rotation device was used (15 rotations/min) during incubation. The same was done with the titanium particles. Cell culture supernatants were then analyzed for interleukin (IL)-1beta, IL-8, and tumor necrosis factor (TNF)-alpha using the enzyme-linked immunosorbent assay technique in the absence or presence of particles. Rotation of incubated MLC alone did not influence the secretion of TNF-alpha, but it enhanced secretion of IL-1beta and IL-8 about 30-fold compared to background levels. Both PE and titanium particles significantly enhanced MLC cytokine release, the amount of which depended on the concentration of particles. Using 40 X 10(8) PE particles (0.7 x 10(8) titanium particles) and 10(6) MLC, the maximal release of IL-1beta was about 20-fold (7-fold titanium particles) higher than that of the rotating control sample. The stimulation of IL-8 release was 4-fold (3-fold titanium particles) and of TNF-alpha. 300-fold (170-fold titanium particles) compared to controls. MLC were viable (>90% cell survival) at concentrations less than 108 x 10(8) polyethylene particles per 10(6) MLC and 16 x 10(8) titanium particles per 10(6) MLC. Rotation per se as well as exposure to increasing concentrations of PE and titanium particles stimulates cytokine release (TNF-alpha, IL-1beta, IL-8) by macrophages in vitro. This in vitro model resembles the in vivo situation near arthroplasties, where implant particles make contact with inflammatory cells, such as macrophages. Cytokine release by macrophages may impair osteoblast function as well as stimulate bone resorption by osteoclasts and macrophages, thereby causing aseptic loosening of arthroplasties. Our in vitro model provides a reproducible human cell system that might shed light on the pathogenesis of particle disease and might serve as a reproducible in vitro test system for the biocompatibility of foreign materials.

Total knee arthroplasty for post-traumatic arthrosis

Abstract: The outcomes of total knee arthroplasty for post-traumatic arthrosis were studied in 31 knees. The average age at arthroplasty was 60 years old (range, 36-78 years). The interval from fracture to total knee arthroplasty averaged 13 years. Simultaneous corrective osteotomy was necessary in 4 patients to correct axial alignment and preserve ligamentous integrity. Follow-up averaged 46 months. Mean arc of motion increased significantly, from 94 degrees to 100 degrees (P = .027). Average function score improved from 44 to 72 points. This change was statistically significant (P<.0001). Knee Society knee scores also improved significantly, from 36 to 78 points (P<.0001). At most recent follow-up, the functional scores were considered excellent or good in 58%; knee scores were considered excellent or good in 71% of cases. All periarticular osteotomies and tibial tubercle osteotomies healed uneventfully within 16 weeks. Complications occurred in 57% of cases, including aseptic failure (26%), septic failure (10%), patellar tendon rupture (3%), patellar subluxation (6%), thromboembolism (6%), and wound breakdown requiring debridement and muscle flap coverage (6%). Despite significant improvements in motion and function, patients with post-traumatic arthrosis are susceptible to high rates of complications. Adverse outcomes can be minimized by restoring limb alignment, soft tissue balance, and component alignment and by preserving vascularity of the skin and subcutaneous tissues.

Porous-coated cementless acetabular cups in revision surgery: a 6- to 11-year follow-up study.

Abstract: Between 1986 and 1991, 65 cementless hemispherical acetabular cups were implanted in 60 patients in revision surgery Different designs were used, including PCA (29 cups), Duraloc (14 cups), Harris-Galante (12 cups), and Omnifit (10 cups) The mean age of patients was 547 years The Paprosky types of the acetabular tone defects were type 1, 2 hips; type 2, 38 hips; type 3A, 15 hips; and type 3B, 10 hips For unrevised hips, the mean follow-up was 83 years (range, 6-11 years) Bone allografts were used in 56 hips: Morcellized cancellous graft was used in 42 hips, structural graft for contained defects was used in 7 hips, and structural graft for uncontained defects was used in 7 hips There were poor clinical results in 14 hips (22%) Re-revision was necessary in 7 hips (108%) There was definite radiographic loosening in 18 hips and possible loosening in 4 hips Screw failure occurred in 6 hips, and a radiolucency in 1 or more DeLee-Charnley zones was apparent in 45 hips (692%) Moderate or severe graft resorption were found in 4 of the 42 morcellized grafts, in 6 of the 7 structural grafts for uncontained defects, and in all 7 of the 7 structural grafts for contained defects The best results were obtained in hips with a bone defect of less than 30% The use of a cementless acetabular cup supplemented with screws is contraindicated in hips with a bone defect greater than 50% Hip reconstruction using structural bone-graft to stabilize the prosthesis gives the worst results

Total hip arthroplasty in patients on long-term renal dialysis.

Abstract: End-stage renal failure patients on long-term renal dialysis who underwent total hip arthroplasty (THA) were followed. Fifteen hips were implanted in 12 patients. There was a high mortality (58%) and high overall early complication rate (58%) with a deep infection rate of 13%. Of patients, 76% (n = 11) had good clinicoradiologic outcome of the THA before their death or at their latest follow-up. THA in patients on dialysis, however, should be reserved for those among this group who are expected to have a better life expectancy.

Patellofemoral complications with the Insall-Burstein II posterior-stabilized total knee arthroplasty.

Abstract: The Insall-Burstein and Insall-Burstein II posterior-stabilized (I-B II PS) prostheses have been reported to have a high prevalence of patellar complications. This is a prospective, consecutive study of 118 primary total knee arthroplasties in 82 patients with the I-B II PS prosthesis implanted by 1 surgeon, using a specific technique for patellar resurfacing. The mean follow-up time was 4.0 years (range, 2-8 years). Clinical evaluation was performed using a standard knee score system with specific additional evaluation of the patellofemoral joint. Radiographs were evaluated for fracture, loosening, and subluxation. Ninety-four knees (80%) were rated excellent, 21 knees (17%) good, and 3 knees (3%) fair. The mean flexion was 112 degrees postoperative. No knee required reoperation for the patellofemoral joint. There were 2 nondisplaced and 1 minimally displaced patellar fractures treated nonoperatively, no patellar clunk syndrome, and no subluxations. Using the patellar evaluation system, 109 knees had no anterior knee pain, 7 knees had mild pain, and 2 knees (1 patient) had moderate-to-severe pain only with rising from a chair. Patellofemoral crepitus with active flexion-extension in the seated position was noted in 16 knees (14%) but was painful in only 2 knees (1 patient). With this technique for patellar resurfacing with this prosthesis, patellofemoral complications were only 4.2%, and no knee required reoperation for the patella or for loosening. With attention to operative technique, patellofemoral resurfacing with this posterior-stabilized total knee arthroplasty can be highly successful.

Prodromes of failure in total knee arthroplasty.

Abstract: A total of 102 revision total knee arthroplasties (TKAs) were reviewed to determine the prodromal symptoms and radiographic findings associated with failure. Presenting symptoms included pain (84%); swelling (76%); progressive varus or valgus deformity (19%); instability (17%); stiffness (17%); clicking or grinding (7%); catching (4%); and patellar pain, subluxation, or clicking (4%). Radiographs were diagnostic in 91% of cases, demonstrating complete radiolucencies (80%), polyethylene wear (43%), component breakage (5%), metallic debris (3%), patellar subluxation or dislocation (4%), and osteolysis (4%). Gross intraoperative findings included polyethylene wear (72%), osteolysis (22%), metal-wear synovitis (9%), component breakage (6%), patellar wear and dissociation (4%), and occult sepsis (5%). The average duration of symptoms was 13 months; the interval between orthopedic evaluations averaged 23 months. Based on this information, we recommend that an annual questionnaire and weight-bearing radiographs be used to ensure adequate surveillance of TKA patients and avoid complications associated with delay in diagnosis of polyethylene wear or implant loosening.

Lessons learned from loosening of the mckee-farrar metal-on-metal total hip replacement

Abstract: Clinical and radiographic data for 15 McKee-Farrar hip replacements that had failed because of aseptic loosening (4 stem loosening, 9 cup loosening, and 2 loosening of both components) between 0.6 and 21 years (average, 8.3 years) were compared with 15 hips in which the McKee-Farrar total hip replacement has survived between 21 and 26 years. Hips that loosened were biomechanically disadvantaged compared with those that demonstrated long-term survival. Radiographic evaluation demonstrated that in hips that were revised for aseptic femoral loosening, the offset was decreased by a mean of 1.4, whereas it was increased by a mean of 4.9 mm in the surviving hips (P = .04). Further, in hips revised for aseptic loosening, the center of rotation was medialized by a mean of only 1.4 mm, whereas the center of rotation was medialized by a mean of 6.4 mm in the surviving hips (P = .1). Unfavorable biomechanics results in increased joint reaction forces that could contribute to loosening of these prostheses. Five of 6 McKee-Farrar stems revised for aseptic loosening compared with 7 of 15 surviving stems were in varus (P = .1) and, as a result, had cement mantle defects in zones III and VII. Thus, in the McKee-Farrar, similar to what has been seen in hips with metal-on-plastic bearings, curved stems are associated with varus positioning, cement mantle defects, and loosening. Wear of the metal-on-metal articulation does not appear to be the cause of failure in these cases. Wear could not be detected radiographically. At revision surgery, there was no indication of excessive bearing wear or gross metal staining of periprosthetic tissues. Microscopic analysis of tissue sections demonstrated both metal and polymethylmethacrylate particles of variable size and shape. The variability of the particles suggests that they are likely the result of loosening and that they were not generated by bearing surface wear that could cause loosening. Although it is hoped that improvements in the wear resistance of the bearing will increase survivorship, this experience and analysis of the McKee-Farrar total hip replacement illustrates the importance of the implant design, biomechanics of the reconstruction, and role of surgical implantation technique.

Eliminating patellofemoral complications in total knee arthroplasty: Clinical and radiographic results of 121 consecutive cases using the Duracon system

Abstract: This study reports the minimum 5-year follow-up of our experience with the Duracon Total Knee Arthroplasty System. A total of 121 consecutive total knee replacements using the Duracon system (Howmedica, Rutherford, NJ) were performed in 104 patients. Three patients died before the 5-year follow-up and were excluded from the final evaluation. The remaining 118 knees (101 patients) were assessed at a mean follow-up of 65 months (range, 60–80 months). The knee diagnoses were osteoarthritis in 97 patients, rheumatoid arthritis in 2 patients, osteonecrosis in 1 patient, and pigmented villonodular synovitis in 1 patient. The mean age was 70 years (range, 28–85 years). There were no reoperations for aseptic loosening, and there have been no reoperations for patellofemoral problems. At final follow-up evaluation, 112 knees (96%) had good or excellent results, and 6 knees (4%) had poor clinical results or went on to revision. For the surviving knees, the preoperative Knee Society objective score improved from a mean of 52 points (range, 20–72 points) to a final follow-up mean of 94 points (range, 66–100 points). Five knees needed reoperations: 2 knees in 1 patient because of acute hematogenous infection at 12 months, 1 knee because of a supracondylar femur fracture, 1 because of a patellar tendon rupture, and 1 to increase polyethylene thickness because of instability. The lack of aseptic loosening at the minimum 5-year follow-up compares favorably with any cemented or cementless series of knee replacement. The almost complete absence of patellofemoral complications in this series also indicates that the design changes, with particular attention to the trochlea design and patellofemoral contact throughout full flexion, have achieved their intended purpose. The results are encouraging at midterm, awaiting true long-term (15–20 years) follow-up.

A rotating-hinge knee replacement for malignant tumors of the femur and tibia

Abstract: We evaluated the 2- to 7-year results of a rotating-hinge knee replacement after excision of malignant tumors of the knee joint. There were 25 distal femoral and 7 proximal tibial replacements. The 5-year prosthetic survival for distal femoral replacements was 88%, compared with 58% for proximal tibial replacements. Seven patients underwent prosthetic exchange: 1 for aseptic loosening, 2 for wound slough and perioperative infection, and 4 for articulating component failure. One patient underwent above-knee amputation owing to skin necrosis. The median functional scores at the latest follow-up were 27 by the International Society of Limb Salvage evaluation system and 80 by the Hospital for Special Surgery Knee Score system. This implant is a promising choice for joint reconstruction after excision of tumors at the knee joint.

A comparison of the midvastus and paramedian approaches for total knee arthroplasty

Abstract: This prospective, double-blinded evaluation of 24 osteoarthritic patients undergoing bilateral total knee replacement compared the midvastus and standard parapatellar approaches. The midvastus approach was found to offer an early advantage in terms of less pain and earlier return to function. There were no significant complications associated with the midvastus approach. This approach should be a part of the knee surgeon's armamentarium.

Cancer incidence in finnish hip replacement patients from 1980 to 1995: A nationwide cohort study involving 31,651 patients

Abstract: Nationwide, computer-based reporting of all arthroplasties performed in Finland was started in January 1980. Using data from these records, a cohort of 31,651 polyethylene-on-metal total hip arthroplasty (THA) patients was followed up for cancer, using Finnish Cancer Registry data, from 1980 to 1995. During follow-up, 2,367 cancers were observed. There were statistically significantly fewer cancers among the THA patients (standardized incidence ratio [SIR], 0.90; 95% confidence interval [CI], 0.87-0.93). SIRs for cancers of the lung (0.69) and stomach (0.77) were significantly below unity. There was no significantly increased risk at any site. The SIR for cancer overall in male THA patients was below unity during the first 3 years after THA but returned to unity thereafter. The low SIR among men during the first 3 years was largely because the lung cancer SIR was 0.47 (95% CI, 0.35-0.62). In women, the SIR remained around 0.93 throughout follow-up. The SIR for stomach cancer was below unity only in women (SIR, 0.67; 95% CI, 0.51-0.86). For cancer of the urinary bladder, the SIR during the first 3 years after THA was below unity but later slightly above it (SIR, 1.24 in relation to > or =3 years of follow-up; 95% CI, 0.99-1.52). For myeloma and leukemia, SIRs were greater than unity only for THA patients followed up for 3 to 9 years. The study findings, in contrast to previously reported findings, do not indicate that there is any increased risk of hematopoietic cancers after THA using polyethylene-on-metal prostheses. SIRs relating to soft tissue cancers and bone sarcomas did not differ significantly from unity. No sarcoma was observed at the site of a prosthesis. THA seems to play no major role in cancer causation.

Injury to the popliteal artery and its anatomic location in total knee arthroplasty.

Abstract: Injury to the popliteal artery during total knee arthroplasty (TKA) is a devastating complication. Although infrequent, these injuries can result in the need for further surgery, including revascularization or possibly even amputation. Several mechanisms are capable of producing direct trauma to the popliteal artery, including the use of posterior ret ractors. We investigated the proximity of the popliteal artery to the tibial joint surface during TKA to identify crucial steps in the procedure at which the artery was at highest risk for injury. TKA was performed on cadaveric specimens, and serial intraoperative arteriograms were taken throughout the procedure, demonstrating the potential for arterial injury by the instrumentation. Additionally, 50 transverse magnetic resonance imaging scans of unrelated knees were analyzed for the position of the popliteal artery relative to the midline of the tibial plateau as well as at a level 5 to 10 mm below this, at the site of a typical resection during TKA. All of the arteriograms showed the artery to be a lateral structure at the joint line. Additionally a posterior retractor placed the artery at risk when it was placed in a position lateral to the posterior cruciate ligament or when it was injudiciously inserted more than 1 cm into the soft tissues. Hyperextension of the knee, which might occur during preparation of the patella, produced dramatic tenting of the artery over the posterior joint line. These results demonstrate that the popliteal artery is at significant risk during TKA, particularly if posterior retractors are placed in a position lateral to the midline of the joint. Both hyperflexion and especially hyperextension produced severe deformities and kinking of the artery and would particularly jeopardize an artery with atherosclerosis. Our findings suggest that the popliteal artery may be at least risk during TKA if posterior retractors are placed medial to the midline of the tibial plateau and if care is taken to avoid extremes of both flexion and extension.