What can be learned from minimum 20-year followup studies of knee arthroplasty?

BACKGROUND: Long-term evaluation of knee arthroplasty should provide relevant information concerning the durability and performance of the implant and the procedure. Because most arthroplasties are performed in older patients, most long-term followup studies have been performed in elderly cohorts and have had low patient survivorship to final followup; the degree to which attrition from patient deaths over time in these studies might influence their results has been poorly characterized. QUESTIONS/PURPOSES: The purpose of this study was to examine the results at 20-year followup of two prospectively followed knee arthroplasty cohorts to determine the following: (1) Are there relevant differences among the two implant cohorts in terms of revision for aseptic causes (osteolysis, or loosening)? (2) How does patient death over the long followup interval influence the comparison, and do the comparisons remain valid despite the high attrition rates? METHODS: Two knee arthroplasty cohorts from a single orthopaedic practice were evaluated: a modular tibial tray (101 knees) and a rotating platform (119 knees) design. All patients were followed for a minimum of 20 years or until death (mean, 14.1 years; SD 5.0 years). Average age at surgery for both cohorts was >70 years. The indications for the two cohorts were identical (functionally limiting knee pain) and was surgeon-specific (each surgeon performed all surgeries in that cohort). Revision rates through a competing risks analysis for implants and survivorship curves for patients were evaluated. RESULTS: Both of these elderly cohorts showed excellent implant survivorship at 20 years followup with only small differences in revision rates (6% revision versus 0% revision for the modular tibial tray and rotating platform, respectively). However, attrition from patient deaths was substantial and overall patient survivorship to 20-year followup was only 26%. Patient survivorship was significantly higher in patients<65 years of age in both cohorts (54% versus 15%, p<0.001 modular tray cohort, and 52% versus 26%, p=0.002 rotating platform cohort). Furthermore, in the modular tray cohort, patients<65 years had significantly higher revision rates (15% versus 3%, p=0.0019). CONCLUSIONS: These two cohorts demonstrate the durability of knee arthroplasty in older patients (the vast majority older than 65 years). Unfortunately, few patients lived to 20-year followup, thus introducing bias into the analysis. These data may be useful as a reference for the design of future prospective studies, and consideration should be given to enrolling younger patients to have robust numbers of living patients at long-term followup. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Custom intramedullary intercalating device for treatment of supracondylar fracture between constrained total knee arthroplasty and well-fixed total hip arthroplasty.

Management of periprosthetic fractures between ipsilateral total knee arthroplasty (TKA) and total hip arthroplasty (THA) is difficult, and is further complicated in the setting of poor femoral bone stock. We present a case of supracondylar fracture between THA and long-stemmed TKA femoral components in a patient with rheumatoid arthritis, deficient metaphyseal bone stock, and recurrent fractures. A long custom intramedullary intercalating component was devised to link the well-fixed existing THA stem to a revision distal femoral component. The resulting construct was stable and allowed for full weight-bearing ambulation, representing a useful treatment option in the management of periprosthetic fractures between revision TKA and well-fixed THA.

Total hip arthroplasty surgical approach does not alter postoperative gait mechanics one year after surgery.

OBJECTIVE: To investigate the differences in gait biomechanics on the basis of surgical approach 1 year after surgery. DESIGN: This was a descriptive laboratory study to investigate the side-to-side differences in walking mechanics at a self-selected walking speed as well as a functional assessment 1 year after total hip arthroplasty (THA). Temporospatial, kinetic, and kinematic data as well as functional outcomes were collected. Two-way analysis of variance was used to assess for between-group differences and limb-to-limb asymmetries. SETTING: A controlled laboratory study. PARTICIPANTS: This study examined 35 patients with primary, unilateral THA. The THA surgical approaches that were used in these patients included 12 direct lateral, 18 posterior, and 11 anterolateral. All the patients were assessed 1 year after THA. Patients were excluded from the study if they had contralateral hip pain or pathology, or any prior lower extremity total joint replacements. MAIN OUTCOME MEASUREMENTS: Three-dimensional lower extremity kinematics and kinetics as well as spatiotemporal variables were collected. In addition, a series of physical performance measures were collected. RESULTS: No main effects for the physical performance measures or biomechanical variables were observed among the approach groups. Significant limb-to-limb asymmetries were observed among all the patients, with decreased sagittal plane range of motion, peak extension, and peak vertical ground reaction forces on the operative side. CONCLUSION: The results of this study indicated that no significant differences existed among the different surgical approach groups for any study variable. However, 1 year after THA, the patients demonstrated asymmetric gait patterns regardless of surgical approach, which indicated the potential need for continued intervention through physical therapy to regain normal side-to-side symmetry after THA.

Does surgical approach during total hip arthroplasty alter gait recovery during the first year following surgery?

Multiple surgical approaches exist for total hip arthroplasty (THA). Each approach has risks and benefits in regard to complications and changes in postoperative gait. This study examined the effect of three surgical approaches on postoperative gait mechanics. Thirty patients completed a self-selected speed level walking gait assessment preoperatively, 6 weeks, and 1 year after surgery. We found no difference between approaches 1 year following surgery for any study variable. Several differences existed between time points independent of surgical approach. Significant improvement was found in sagittal and frontal plane hip ROM, peak hip extension and adduction angle and moment, the functional measures, walking speed, and the Harris Hip Score. This study suggests that postoperative gait changes are similar for the three analyzed surgical approaches.

Durability of a cruciate-retaining TKA with modular tibial trays at 20 years.

BACKGROUND: Modular tibial trays have been utilized in TKA for more than 20 years. However, concerns have been raised about modular implants and it is unclear whether these devices are durable in the long term. QUESTIONS/PURPOSES: We determined (1) survival, (2) relationship of age and polyethylene thickness with revision, (3) function, and (4) radiographic lucencies and osteolysis in patients having a single TKA implant at 20-year followup. METHODS: We prospectively followed 75 patients implanted with 101 Press-Fit Condylar(®) (Johnson and Johnson Professional, Inc, Raynham, MA, USA) posterior cruciate-retaining TKAs (with modular tibial trays) between 1988 and 1991. At 20 years, 59 patients were deceased. We clinically evaluated the living 16 patients (22 knees) and contacted the relatives of all deceased patients to confirm implant status. We clinically assessed 14 of the 16 patients with the Knee Society score, WOMAC, and UCLA and Tegner activity level scores. Radiographically, we determined lucencies, component migration, and osteolysis. We performed survival analysis including all original patients. Minimum followup was 20 years (mean, 20.6 years; range, 20-21.8 years). RESULTS: Six reoperations were performed in five patients (6% rate of revision) over the 20-year followup. All revisions were related to polyethylene wear and occurred at least 10 years after the primary procedure. Survivorship with revision for any reason as the end point was 91% (95% CI, 0.83-0.97) at 20 years. Average Knee Society clinical and functional scores were 90 (range, 60-100) and 59 (range, 30-87), respectively. CONCLUSIONS: Our data demonstrate the durability of this posterior cruciate-retaining TKA design. The data provide a standard for newer designs and newer bearing surface materials at comparable followup.

Response of Chondrocytes to Local Mechanical Injury in an Ex Vivo Model.

BACKGROUND: Our goal was to set up an ex vivo culture system to assess whether cartilage wounding (partial-thickness defects) can induce morphological changes in neighboring chondrocytes and whether these cells can translocate to the surface of the defect. METHODS: Two-millimeter partial-depth defects were created in human osteochondral explants followed by culture for up to 4 weeks. Frozen sections of defects and defect-free regions were labeled using immunofluorescence for a plasma membrane protein, CD44, and actin with TRITC-phalloidin. Viable nuclei were detected with Hoechst 33342. Differential interference contrast (DIC), confocal, and transmission electron microscopy (TEM) were used to examine process extension. RESULTS: Significant changes in cell morphology occurred in response to wounding in the superficial and deep cartilage zones. These included cell flattening, polarization of the actin cytoskeleton, extension of pseudopods projecting towards the edge of the defect, and interactions of these filopodia with collagen fibers. Cell density decreased progressively in the 300-µm zone adjacent to the defect to an average of approximately 25% to 35% after 3 weeks. Concomitant increases in cell density in the defect margin were observed. By contrast, minimal changes were seen in the middle cartilage zone. CONCLUSIONS: These novel observations strongly suggest active cartilage cell responses and movements in response to wounding. It is proposed that cartilage cells use contact guidance on fibrillated collagen to move into and populate defect areas in the superficial and deep zones.

The Rottinger approach for total hip arthroplasty: technique and review of the literature.

The surgical approach utilized in total hip arthroplasty has been identified as a factor that may affect surgical outcomes. There have been many different approaches and modifications used since the procedure was popularized by Sir John Charnley. The popular approaches today can be grouped by their relationship to the trochanter (anterior or posterior), patient position, leg position for dislocation/femoral preparation, and treatment of the abductors and short external rotators. The Rottinger approach is an anterior approach which utilizes the muscle interval between the tensor fascia lata and abductor musculature. The abductor attachments are preserved and the femur is prepared in extension, adduction, and external rotation. This approach has been shown in literature to be safe with some studies showing improved outcomes both in terms of reduced complications and better function than other standard approaches.

The effect of total hip arthroplasty surgical approach on postoperative gait mechanics.

Surgical approach for total hip arthroplasty (THA) is determined by clinician preference from limited prospective data. This study aimed to examine the effect of surgical approach (direct lateral, posterior, and anterolateral) on 6-week postoperative gait mechanics. Thirty-five patients (direct lateral, 8; posterior, 12; anterolateral, 15) were tested preoperatively and 6 weeks after THA. Patients underwent a gait analysis at a self-selected walking speed. A 2-way analysis of variance was used for analysis. Stride length, step length, peak hip extension, and walking speed increased after THA. The 3 surgical approach variables were not significantly different for any of the study variables after THA. All patients showed some increase in selected variables after THA regardless of surgical approach. In this study, surgical approach did not appear to significantly influence the early postoperative gait mechanics that were quantified.

Routine surveillance of modular PFC TKA shows increasing failures after 10 years.

BACKGROUND/RATIONALE: A 10-year survivorship of 100% was reported for patients with PFC cruciate-retaining prostheses. Beyond 10 years, we observed additional polyethylene wear likely related to thin liners gamma-irradiated in air and were concerned this wear might predispose to implant construct failure. QUESTIONS/PURPOSES: We therefore determined (1) the functional scores at a minimum of 15 years followup, (2) rates of radiographic failure, (3) overall revision rates, and (4) mode of failure after 10 years and the fate of the revised implants. METHODS: We retrospectively reviewed 75 patients with 101 press-fit condylar posterior cruciate-retaining prostheses. At a minimum followup of 15 years, 35 patients (47 knees) were living and evaluated clinically. No patients were lost to followup. RESULTS: There were no revisions during the first 11 years and six reoperations subsequently were performed in five patients (6% overall rate of revision but 12.8% in patients who survived more than 15 years). Three of six revisions had concerning liner wear at 10 years and all six were revised for polyethylene wear. Polyethylene exchange was performed in four of the five patients who underwent revisions, all of whom were doing well at an average of 7.2 years (range, 4.7-9.1 years) after the revision procedure. CONCLUSIONS: At long-term followup, the overall revision rate remained low (6%). For patients surviving 15 years or more, the rate of revision was 12.8% and all revisions were secondary to aseptic sequelae of polyethylene wear. All revisions occurred more than 10 years after the initial procedures. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Activity scale for arthroplasty patients after total hip arthroplasty.

The purpose of the Activity Scale for Arthroplasty Patients (ASAP) is to develop and validate a self-report questionnaire that demonstrated discrimination of functional gains, low burden, appropriate concurrent validity, and was not limited by ceiling effects. We identified 128 high-functioning hip arthroplasty patients from our database who completed a 25-item ASAP and Lower Extremity Functional Scale questionnaires and a set of anchor questions. Factor analysis identified 10 items associated with 2 distinct factors: (1) activities and (2) running and running-related environments. These 10 items were retained and were identified as the ASAP. The ASAP may be useful in high-level hip arthroplasty patients where other scales fail to capture activities secondary to ceiling effects. In addition, the scale burden is minimized by inclusion of only 10 items.

Survival of polished compared with precoated roughened cemented femoral components. A prospective, randomized study.

BACKGROUND: The optimal surface finish for cemented femoral components remains controversial. The purpose of this randomized clinical trial was to compare the survival of two femoral components with similar geometry but substantially different surface finishes. METHODS: During a five-year period, 201 patients (219 hips) were prospectively randomized to be treated with a total hip arthroplasty with either a polished (Ra, 0.18 to 0.3 microm) or a precoated roughened (Ra, 1.8 to 2.3 microm) cemented femoral component with similar geometry. There were no significant differences between the patient groups in terms of age, sex, weight, preoperative diagnosis, component size, or cement grade. So-called third-generation cementing techniques were used. One hundred and thirteen polished components and 106 precoated roughened components were followed for a mean of 5.3 years. Complete clinical and radiographic data were available for 134 hips at a minimum of five years (mean, 6.1 years; range, five to ten years) postoperatively. RESULTS: In the entire cohort of 219 hips, there was no significant difference (log rank p = 0.66) in survival, with the end point defined as component removal for any reason or definite radiographic loosening, between the precoated components (96.2%; 95% confidence interval, 90.9% to 100%) and the polished components (97.1%; 95% confidence interval, 93.8% to 100%). There was a periprosthetic fracture in three hips with a polished component. Two precoated roughened components were revised because of loosening, and two polished components were revised: one because of loosening and one because of a nonunion of a periprosthetic fracture. There was no significant difference between the groups with regard to the Harris hip scores or the clinical results. There was also no significant difference with regard to the presence or number of bone-cement radiolucent lines. CONCLUSIONS: Kaplan-Meier survival analysis showed no significant differences between two types of cemented femoral components with similar geometry but substantially different surface finishes at seven years. In the patient population selected for treatment with a cemented femoral component, the surface finish may not be a crucial factor affecting component survival at a minimum of five years, provided that good cement technique is used.

Characterization of a consistent radiographic finding in chronic anterior cruciate ligament deficiency: the posteromedial osteophyte.

Often found in patients undergoing total knee arthroplasty (TKA) is an osteophyte, at the posterior lateral corner of the medial tibial plateau, that prevents anterior translation. This osteophyte does not occur in the presence of an entirely normal anterior cruciate ligament (ACL) with normal vascularity. Although similar findings have been reported in animal studies, to our knowledge this has never been documented in humans. To determine the incidence of this finding in our patient population, anteroposterior and lateral x-rays of the affected knee of 90 patients undergoing TKA were reviewed. Forty-two percent (43/102 knees) had radiographic signs of this stabilizing osteophyte. This finding confirms previous animal research and may lead to a better understanding of how the knee adapts to improve stability in a chronic ACL-deficient state.

Hip arthroplasty after extracapsular hip fracture: a matched pair cohort analysis.

Eighteen patients with a prior intertrochanteric or basicervical hip fracture had a total or bipolar hip arthroplasty. The clinical and radiographic results of these patients were compared to a control group of patients (matched for age, gender, associated diagnoses, and length of follow-up) who had a primary total hip arthroplasty. There was a significant increase in intraoperative blood loss, operative time, and number of units of blood transfused in the fracture group compared to the primary arthroplasty group. The mean preoperative Harris hip scores were not significantly different between the two groups, but the postoperative scores were significantly lower for the fracture group (p < .001). There was no notable difference in the rates of radiographic loosening or heterotopic ossification between the two groups. The results of this study suggest that patients should be counseled preoperatively that the functional outcome of hip arthroplasty after internal fixation of extracapsular hip fractures is decreased compared to control patients with a primary total hip arthroplasty.

Cementation for femoral head osteonecrosis: a preliminary clinic study.

Treatment for femoral head osteonecrosis has been less successful in late stages of the disease, after progression to collapse. The current authors treated 21 patients (22 hips) with Stage III osteonecrosis by a technique of open reduction and fixation with methylmethacrylate cement (cementation). The followup ranged from 1 to 3 years (average, 1.7 years). Patient progress was followed using preoperative and postoperative Harris hip scores, Western Ontario and McMaster Universities Osteoarthritis Index, and a health status questionnaire (Short Form-36). Patients were staged preoperatively using the Association Research Circulation Osseous international classification system and radiographic evaluation was done intraoperatively and postoperatively. The Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index, and Short Form-36 physical health scores improved significantly from 53.5 to 78.0, 66.0 to 48.1, and 27.0 to 40.0, respectively. The outcome was worse for patients with more advanced disease. Six patients, all with severe disease, had total hip arthroplasty. Cementation is technically simple, enables patients' immediate postoperative pain relief and improvement in mobility, and has the potential to restore and maintain the sphericity of the femoral head after collapse. The high failure rate (27%) at short-term followup, although comparable with other reported techniques, does not support generalized use for Stage III disease. Currently the use of this procedure is restricted to symptomatic, young patients (younger than 40 years), preferably with mild to moderate Stage III disease (degree of head involvement < 30% and degree of collapse < 4 mm).

Role of pericellular matrix in development of a mechanically functional neocartilage.

The role of the chondrocyte pericellular matrix (PCM) was examined in a three-dimensional chondrocyte culture system to determine whether retention of the native pericellular matrix could stimulate collagen and proteoglycan accumulation and also promote the formation of a mechanically functional hyaline-like neocartilage. Porcine chondrocytes and chondrons, consisting of the chondrocyte with its intact pericellular matrix, were maintained in pellet culture for up to 12 weeks. Sulfated glycosaminoclycans and type II collagen were measured biochemically. Immunocytochemistry was used to examine collagen localization as well as cell distribution within the pellets. In addition, the equilibrium compressive moduli of developing pellets were measured to determine whether matrix deposition contributed to the mechanical stiffness of the cartilage constructs. Pellets increased in size and weight over a 6-week period without apparent cell proliferation. Although chondrocytes quickly rebuilt a PCM rich in type VI collagen, chondron pellets accumulated significantly more proteoglycan and type II collagen than did chondrocyte pellets, indicating a greater positive effect of the native PCM. After 5 weeks in chondron pellets, matrix remodeling was evident by microscopy. Cells that had been uniformly distributed throughout the pellets began to cluster between large areas of interterritorial matrix rich in type II collagen. After 12 weeks, clusters were stacked in columns. A rapid increase in compressive strength was observed between 1 and 3 weeks in culture for both chondron and chondrocyte pellets and, by 6 weeks, both had achieved 25% of the equilibrium compressive stiffness of cartilage explants. Retention of the in vivo PCM during chondrocyte isolation promotes the formation of a mechanically functional neocartilage construct, suitable for modeling the responses of articular cartilage to chemical stimuli or mechanical compression.

Posterior cruciate-retaining modular total knee arthroplasty: a 9- to 12-year follow-up investigation.

Between November 1988 and January 1991, 101 press-fit condylar (PFC; Johnson & Johnson, Raynham, MA) posterior cruciate-retaining total knee arthroplasties were performed in 75 patients. All tibial components were modular metal-backed, and all patellar components were all-polyethylene. All living patients were evaluated at an average 10.5 years (range, 9.5-11.8 years). Only 1 knee required revision (at 11.1 years after the procedure), and only 1 other knee had evidence of radiographic failure. The average range of motion was 1 degrees (range, 0 degrees -10 degrees ) to 110 degrees (range, 86 degrees -130 degrees ). At 10 years of follow-up, the probability of prosthesis survival was 100%, and at 12 years, the probability of prosthesis survival was 93.3% (endpoint defined as revision for any reason).

Development of selective tolerance to interleukin-1beta by human chondrocytes in vitro.

Interleukin-1 induces release of NO and PGE(2) and production of matrix degrading enzymes in chondrocytes. In osteoarthritis (OA), IL-1 continually, or episodically, acts on chondrocytes in a paracrine and autocrine manner. Human chondrocytes in chondron pellet culture were treated chronically (up to 14 days) with IL-1beta. Chondrons from OA articular cartilage were cultured for 3 weeks before treatment with IL-1beta (0.05-10 ng/ml) for an additional 2 weeks. Spontaneous release of NO and IL-1beta declined over the pretreatment period. In response to IL-1beta (0.1 ng/ml), NO and PGE(2) release was maximal on Day 2 or 3 and then declined to near basal level by Day 14. Synthesis was recovered by addition of 1 ng/ml IL-1beta on Day 11. Expression of inducible nitric oxide synthase (iNOS), detected by immunofluorescence, was elevated on Day 2 and declined through Day 14, which coordinated with the pattern of NO release. On the other hand, IL-1beta-induced MMP-13 synthesis was elevated on Day 3, declined on Day 5, and then increased again through Day 14. IL-1beta increased glucose consumption and lactate production throughout the treatment. IL-1beta stimulated proteoglycan degradation in the early days and inhibited proteoglycan synthesis through Day 14. Chondron pellet cultures from non-OA cartilage released the same amount of NO but produced less PGE(2) and MMP-13 in response to IL-1beta than OA cultures. Like the OA, IL-1beta-induced NO and PGE(2) release decreased over time. In conclusion, with prolonged exposure to IL-1beta, human chondrocytes develop selective tolerance involving NO and PGE(2) release but not MMP-13 production, metabolic activity, or matrix metabolism.

Retention of the native chondrocyte pericellular matrix results in significantly improved matrix production.

The interaction of the cell with its surrounding extracellular matrix (ECM) has a major effect on cell metabolism. We have previously shown that chondrons, chondrocytes with their in vivo-formed pericellular matrix, can be enzymatically isolated from articular cartilage. To study the effect of the native chondrocyte pericellular matrix on ECM production and assembly, chondrons were compared with chondrocytes isolated without any pericellular matrix. Immediately after isolation from human cartilage, chondrons and chondrocytes were centrifuged into pellets and cultured. Chondron pellets had a greater increase in weight over 8 weeks, were more hyaline appearing, and had more type II collagen deposition and assembly than chondrocyte pellets. Minimal type I procollagen immunofluorescence was detected for both chondron and chondrocyte pellets. Chondron pellets had a 10-fold increase in proteoglycan content compared with a six-fold increase for chondrocyte pellets over 8 weeks (P<0.0001). There was no significant cell division for either chondron or chondrocyte pellets. The majority of cells within both chondron and chondrocyte pellets maintained their polygonal or rounded shape except for a thin, superficial edging of flattened cells. This edging was similar to a perichondrium with abundant type I collagen and fibronectin, and decreased type II collagen and proteoglycan content compared with the remainder of the pellet. This study demonstrates that the native pericellular matrix promotes matrix production and assembly in vitro. Further, the continued matrix production and assembly throughout the 8-week culture period make chondron pellet cultures valuable as a hyaline-like cartilage model in vitro.