Outcomes of trabecular metal total ankle replacement: a longitudinal observational cohort study of 239 consecutive cases from the Swedish Ankle Registry.

BACKGROUND AND PURPOSE: Information on outcomes after some modern total ankle replacement (TAR) designs is scarce. We therefore examined outcomes after trabecular metal (TM) TAR in Sweden by use of data from the national registry. PATIENTS AND METHODS: On December 31, 2020, 239 primary TM TARs had been reported to the Swedish Ankle Registry. We analyzed prosthesis survival probability, using exchange or permanent extraction of components as endpoint for 239 protheses with mean follow-up of 2.2 years (0.1-6.6), risk of revision, as well as patient-reported outcome measures (SEFAS/EQ-5D/EQ-VAS) and satisfaction with surgery. RESULTS: 7/239 prostheses (3%) had been revised by December 31, 2020. We found an overall prosthesis survival probability of 95% (95% CI 89-98) after 3 years. 2 years after surgery 81% of the answering patients were satisfied or very satisfied with surgery and patients reported median SEFAS 36 (max 48), EQ-5D 0.90 (max 1), and EQ-VAS 80 (max 100). INTERPRETATION: We found short- to mid-term outcomes after TM TAR to be at least as good as after other TAR designs regarding prosthesis survival and patient-reported satisfaction.

Better implant survival with modern ankle prosthetic designs: 1,226 total ankle prostheses followed for up to 20 years in the Swedish Ankle Registry.

Background and purpose - We have previously reported on the prosthetic survival of total ankle replacements (TAR) in Sweden performed between 1993 and 2010. Few other reports have been published on 5- and 10-year survival rates. Furthermore, there is a lack of long-term outcome data on modern prosthetic designs. Therefore, we compared early and current prosthetic designs after a mean 7-year follow-up.Patients and methods - On December 31, 2016, 1,230 primary TARs had been reported to the Swedish Ankle Registry. We analyzed prosthetic survival, using exchange or permanent extraction of components as endpoint for 1,226 protheses with mean follow-up of 7 years (0-24). Differences between current (Hintegra, Mobility, CCI, Rebalance, and TM Ankle) and early prosthetic designs (STAR, BP, and AES) were examined by log rank test.Results - 267/1,226 prostheses (22%) had been revised by December 31, 2016. We found an overall prosthetic survival rate at 5 years of 0.85 (95% CI 0.83-0.87), at 10 years 0.74 (CI 0.70-0.77), at 15 years 0.63 (CI 0.58-0.67), and at 20 years 0.58 (CI 0.52-0.65). For early prosthetic designs the 5- and 10-year survival rates were 0.81 (CI 0.78-0.84) and 0.69 (CI 0.64-0.73) respectively, while the corresponding rates for current designs were 0.88 (CI 0.85-0.91) and 0.84 (CI 0.79-0.88). Current prosthetic designs had better survival (log rank test p < 0.001).Interpretation - Our results point to a positive time trend of prosthetic survival in Sweden; use of current prosthetic designs was associated with better prosthetic survival. Improved designs and instrumentation, more experienced surgeons, and improved patient selection may all have contributed to the better outcome.

Re-arthrodesis after primary ankle fusion: 134/1,716 cases from the Swedish Ankle Registry.

Background and purpose - Arthrodesis is the most common treatment of severe ankle arthritis. Large studies on the occurrence of re-arthrodesis are few, especially with information in terms of risk. We used the National Swedish Ankle Registry to assess incidence and risk factors for re-arthrodesis. Patients and methods - In the Registry, we examined the occurrence of re-arthrodesis in 1,716 patients with a primary ankle arthrodesis. We also analyzed associations between the re-arthrodesis risk and sex, diagnosis, and surgical method. Results - The risk of first re-arthrodesis at 2.5 years was 7.4% and the rate at 9 years 7.8%. The risk following arthroscopic surgery with fixation by screws was 15%, which is statistically significantly higher than the 8% following the gold standard technique with open screw fixation, the 5% following fixation by intramedullary nailing, and the 3% following fixation by plate and screws. Patients with either idiopathic osteoarthritis or posttraumatic arthritis had a higher risk of re-arthrodesis than patients with rheumatoid arthritis. We could not find that the risk of re-arthrodesis was associated with sex. Interpretation - In Sweden, the re-arthrodesis risk varied by primary technique and was especially high after arthroscopic surgery. Reasons are unknown but poor surgical technique and/or surgeon inexperience may contribute, as may patient selection.

Good outcome scores and high satisfaction rate after primary total ankle replacement.

Background and purpose - Total ankle replacement (TAR) is gaining popularity for treatment of end-stage ankle arthritis. Large patient-centered outcome studies are, however, few. Here, we report data from the Swedish Ankle Registry. Patients and methods - We examined outcomes after primary TAR in patients from the Swedish Ankle Registry using PROMs (Patient Reported Outcome Measures; generic: EQ-5D and SF-36, region specific: SEFAS (Self-Reported Foot and Ankle Score), and a question on satisfaction). We included 241 patients registered with primary TAR between 2008 and 2016 and who completed PROMs preoperatively and postoperatively up to 24 months. We evaluated changes in PROMs following surgery and estimated effects of age, diagnosis, prosthetic design, and preoperative functional score on the outcomes. Results - All absolute scores improved from preoperative to 24 months after surgery (p ≤ 0.001). 71% of the patients were satisfied or very satisfied at the latest follow-up and 12% dissatisfied or very dissatisfied. Postoperative SEFAS correlated with age (r = 0.2, p = 0.01) and preoperative SEFAS (r = 0.3, p < 0.001), as did patient satisfaction (r = -0.2; p ≤ 0.03). Postoperative SEFAS and EQ-5D were similar between different diagnoses or prosthetic designs. Preoperative SF-36 was associated with diagnosis (p ≤ 0.03), postoperative SF-36 with age (r = 0.2, p = 0.01) and diagnosis (p < 0.03). Interpretation - We found statistically and clinically significant improvements in patient-reported outcomes following TAR surgery. The postoperative region-specific SEFAS was positively associated with older age. Prosthetic design seemed not to influence patient-reported outcome, whereas diagnosis partly did. Studies with longer follow-up are necessary to establish the long-term outcome of TAR and to elucidate whether short- and mid-term outcomes may predict implant failure.

Bilateral Arthrodesis of the Ankle Joint: Self-Reported Outcomes in 35 Patients From the Swedish Ankle Registry.

Bilateral ankle arthrodesis is seldom performed, and results concerning the outcome and satisfaction can only sparsely be found in published studies. We analyzed the data from 35 patients who had undergone bilateral ankle arthrodesis in the Swedish Ankle Registry using patient-reported generic and region-specific outcome measures. Of 36 talocrural arthrodeses and 34 tibio-talar-calcaneal arthrodeses, 6 ankles (9%) had undergone repeat arthrodesis because of nonunion. After a mean follow-up period of 47 ± 5 (range 12 to 194) months, the mean scores were as follows: self-reported foot and ankle score, 33 ± 10 (range 4 to 48); the EuroQol Group's EQ-5D™ score, 0.67 ± 0.28 (range -0.11 to 1), the EuroQol Group's visual analog scale score, 70 ± 19 (range 20 to 95), 36-item Short Form Health Survey (SF-36) physical domain, 39 ± 11 (range 16 to 58); and SF-36 mental domain, 54 ± 14 (range 17 to 71). Patients with rheumatoid arthritis seemed to have similar self-reported foot and ankle scores but possibly lower EQ-5D™ and SF-36 scores. Those with talocrural arthrodeses scored higher than did those with tibio-talar-calcaneal arthrodeses on the EQ5D™ and SF-36 questionnaires (p = .03 and p = .04). In 64 of 70 ankles (91%), the patients were satisfied or very satisfied with the outcome. In conclusion, we consider bilateral ankle arthrodesis to be a reasonable treatment for symptomatic hindfoot arthritis, with high postoperative mid-term satisfaction and satisfactory scores on the patient-reported generic and region-specific outcome measures, when no other treatment option is available.

Total ankle replacement and contralateral ankle arthrodesis in 16 patients from the Swedish Ankle Registry: Self-reported function and satisfaction.

BACKGROUND: Both total ankle replacement (TAR) and ankle arthrodesis do show some problems in long-term studies. To choose either of these surgical options is a delicate task. There are no randomized studies reported in the literature and no previous studies in which patients constitute the own controls. METHODS: Patients with a TAR and a contralateral ankle arthrodesis were identified in the Swedish Ankle Register. A self-reported foot and ankle specific questionnaire (SEFAS) was sent to these patients who also were asked to report their grade of satisfaction from 1 to 5. RESULTS: The median SEFAS score was 32 (16-44) for the prostheses and 27 (14-47) for the arthrodeses. The median satisfaction score was 2 (1-4) for the prostheses and 2 (1-5) for the arthrodeses. There were no statistically significant difference between the prosthetic side and the fused side regarding these scores. CONCLUSION: Patients who had undergone ankle arthrodesis on one side and had the contralateral ankle replaced, were equally satisfied with both procedures.

Poor prosthesis survival and function after component exchange of total ankle prostheses.

BACKGROUND AND PURPOSE: In failed total ankle replacements (TARs), fusion is often the procedure of preference; the outcome after exchanging prosthetic components is debated. We analyzed prosthetic survival, self-reported function, and patient satisfaction after component exchange. Patients and methods We identified patients in the Swedish Ankle Registry who underwent exchange of a tibial and/or talar component between January 1, 1993 and July 1, 2013 and estimated prosthetic survival by Kaplan-Meier analysis. We evaluated the patient-reported outcome measures (PROMs) SEFAS, EQ-5D, EQ-VAS, SF-36, and patient satisfaction by direct questions. RESULTS: 69 patients underwent revision TAR median 22 (0-110) months after the primary procedure. 24 of these failed again after median 26 (1-110) months. Survival analysis of revision TAR showed a 5-year survival rate of 76% and a 10-year survival of 55%. 29 patients with first revision TAR in situ answered the PROMs at mean 8 (1-17) years after revision and had the following mean scores: SEFAS 22, SF-36 physical 37 and mental 49, EQ-5D index 0.6, and EQ-VAS 64. 15 of the patients were satisfied, 5 were neither satisfied nor dissatisfied, and 9 were dissatisfied. INTERPRETATION: Revision TAR had a 10-year survival of 55%, which is lower than the 10-year survival of 74% for primary TAR reported from the same registry. Only half of the patients were satisfied. Future studies should show which, if any, patients benefit from revision TAR and which patients should rather be fused directly.

Validity, reliability, and responsiveness of the Self-reported Foot and Ankle Score (SEFAS) in forefoot, hindfoot, and ankle disorders.

BACKGROUND AND PURPOSE: The self-reported foot and ankle score (SEFAS) is a questionnaire designed to evaluate disorders of the foot and ankle, but it is only validated for arthritis in the ankle. We validated SEFAS in patients with forefoot, midfoot, hindfoot, and ankle disorders. PATIENTS AND METHODS: 118 patients with forefoot disorders and 106 patients with hindfoot or ankle disorders completed the SEFAS, the foot and ankle outcome score (FAOS), SF-36, and EQ-5D before surgery. We evaluated construct validity for SEFAS versus FAOS, SF-36, and EQ-5D; floor and ceiling effects; test-retest reliability (ICC); internal consistency; and agreement. Responsiveness was evaluated by effect size (ES) and standardized response mean (SRM) 6 months after surgery. The analyses were done separately in patients with forefoot disorders and hindfoot/ankle disorders. RESULTS: Comparing SEFAS to the other scores, convergent validity (when correlating foot-specific questions) and divergent validity (when correlating foot-specific and general questions) were confirmed. SEFAS had no floor and ceiling effects. In patients with forefoot disorders, ICC was 0.92 (CI: 0.85-0.96), Cronbach's α was 0.84, ES was 1.29, and SRM was 1.27. In patients with hindfoot or ankle disorders, ICC was 0.93 (CI: 0.88-0.96), Cronbach's α was 0.86, ES was 1.05, and SRM was 0.99. INTERPRETATION: SEFAS has acceptable validity, reliability, and responsiveness in patients with various forefoot, hindfoot, and ankle disorders. SEFAS is therefore an appropriate patient- reported outcome measure (PROM) for these patients, even in national registries.

Fixation of the fully hydroxyapatite-coated Corail stem implanted due to femoral neck fracture: 38 patients followed for 2 years with RSA and DEXA.

BACKGROUND: Today, dislocated femoral neck fractures are commonly treated with a cemented hip arthroplasty. However, cementing of the femoral component may lead to adverse effects and even death. Uncemented stems may lower these risks and hydroxyapatite (HA) coating may enhance integration, but prosthetic stability and clinical outcome in patients with osteoporotic bone have not been fully explored. We therefore studied fixation and clinical outcome in patients who had had a femoral neck fracture and who had received a fully HA-coated stem prosthesis. PATIENTS AND METHODS: 50 patients with a dislocated femoral neck fracture were operated with the fully HA-coated Corail total or hemiarthroplasty. 38 patients, mean age 81 (70-96) years, were followed for 24 months with conventional radiographs, RSA, DEXA, and for clinical outcome. RESULTS: 31 of the 38 implants moved statistically significantly up to 3 months, mainly distally, mean 2.7 mm (max. 20 mm (SD 4.3)), and rotated into retroversion mean 3.3º (-1.8 to 17) (SD 4.3) and then appeared to stabilize. Distal stem migration was more pronounced if the stem was deemed to be too small. There was no correlation between BMD and stem migration. The migration did not result in any clinically adverse effects. INTERPRETATION: The fully hydroxyapatite-coated Corail stem migrates during the first 3 months, but clinical outcome appears to be good, without any adverse events.

Validity, reliability, and responsiveness of a self-reported foot and ankle score (SEFAS).

BACKGROUND AND PURPOSE: A questionnaire was introduced by the New Zealand Arthroplasty Registry for use when evaluating the outcome of total ankle replacement surgery. We evaluated the reliability, validity, and responsiveness of the modified Swedish version of the questionnaire (SEFAS) in patients with osteoarthritis or inflammatory arthritis before and/or after their ankle was replaced or fused. PATIENTS AND METHODS: The questionnaire was translated into Swedish and cross-culturally adapted according to a standardized procedure. It was sent to 135 patients with ankle arthritis who were scheduled for or had undergone surgery, together with the foot and ankle outcome score (FAOS), the short form 36 (SF-36) score, and the EuroQol (EQ-5D) score. Construct validity was evaluated with Spearman's correlation coefficient when comparing SEFAS with FAOS, SF-36, and EQ-5D, content validity by calculating floor and ceiling effects, test-retest reliability with intraclass correlation coefficient (ICC), internal consistency with Cronbach's alpha (n = 62), agreement by Bland-Altman plot, and responsiveness by effect size and standardized response mean (n = 37). RESULTS: For construct validity, we correlated SEFAS with the other scores and 70% or more of our predefined hypotheses concerning correlations could be confirmed. There were no floor or ceiling effects. ICC was 0.92 (CI 95%: 0.88-0.95), Cronbach's alpha 0.96, effect size was 1.44, and the standardized response mean was 1.00. INTERPRETATION: SEFAS is a self-reported foot and ankle score with good validity, reliability and responsiveness, indicating that the score can be used to evaluate patients with osteoarthritis or inflammatory arthritis of the ankle and outcome of surgery.

10-year survival of total ankle arthroplasties: a report on 780 cases from the Swedish Ankle Register.

BACKGROUND AND PURPOSE: There is an ongoing need to review large series of total ankle replacements (TARs) for monitoring of changes in practice and their outcome. 4 national registries, including the Swedish Ankle Register, have previously reported their 5-year results. We now present an extended series with a longer follow-up, and with a 10-year survival analysis. PATIENTS AND METHODS: Records of uncemented 3-component TARs were retrospectively reviewed, determining risk factors such as age, sex, and diagnosis. Prosthetic survival rates were calculated with exchange or removal of components as endpoint-excluding incidental exchange of the polyethylene meniscus. RESULTS: Of the 780 prostheses implanted since 1993, 168 (22%) had been revised by June 15, 2010. The overall survival rate fell from 0.81 (95% CI: 0.79-0.83) at 5 years to 0.69 (95% CI: 0.67-0.71) at 10 years. The survival rate was higher, although not statistically significantly so, during the latter part of the period investigated. Excluding the STAR prosthesis, the survival rate for all the remaining designs was 0.78 at 10 years. Women below the age of 60 with osteoarthritis were at a higher risk of revision, but age did not influence the outcome in men or women with rheumatoid arthritis. Revisions due to technical mistakes at the index surgery and instability were undertaken earlier than revisions for other reasons. INTERPRETATION: The results have slowly improved during the 18-year period investigated. However, we do not believe that the survival rates of ankle replacements in the near future will approach those of hip and knee replacements-even though improved instrumentation and design of the prostheses, together with better patient selection, will presumably give better results.

The Elite-Plus stem migrates more than the flanged Charnley stem.

BACKGROUND AND PURPOSE: The Charnley Elite-Plus stem was introduced in 1993 as a presumed improvement of the flanged Charnley stem. We started this study in 1996 to investigate the migratory pattern of the Elite-Plus stem. PATIENTS AND METHODS: We followed 114 patients with osteoarthritis and a primary total hip replacement with the Elite-Plus stem. Mean age at the time of operation was 64 (50-76) years. The mean follow-up time was 6.5 (2-7) years. Radiographs were evaluated with respect to cementing technique, migration, and wear measured by radiostereometry (RSA). RESULTS: The stem survival was 98% (CI: 96-100) at 7 years and 92% (CI: 86-97) at 10 years. Mean migration of the femoral head was 0.35 mm (SD 0.3) medially, 0.51 mm (SD 0.6) distally, and 1.1 mm (SD 1.8) in the dorsal direction. Mean total point motion was 1.7 mm (SD 1.7). The migration of the stems stabilized after 5 years in the medial and dorsal directions, but continued to subside slightly. Migration along any of the axes was higher if the cementing technique was inferior. INTERPRETATION: Patients with a Charnley Elite-Plus stem and defects in the cement mantle or other signs of inferior implantation technique should be carefully monitored.

A clinical and radiostereometric study of the cemented PFC-sigma prosthesis: a 5-year study of 29 cases with a fixed bearing.

The press-fit condylar (PFC) cruciate-retaining total knee prosthesis is well documented in the literature. In 1997, a modification of the femoral component was introduced, and the prosthesis was renamed PFC-Sigma. The alteration may influence the migratory and rotational pattern of the tibial component and thus long-time survival rate. In this radiostereometric analysis, we found that the micromotion of the PFC-Sigma prosthesis differs slightly from the original PFC design, an advantage of the PFC-Sigma prosthesis. The median maximum total point motion at 5 years was 0.64 mm for the PFC-Sigma design and 0.79 mm for the previous version of PFC (P = .9). However, the PFC-Sigma rotated less around the transverse (x) axis than did the PFC (medians, 0.22 mm and 0.48 mm, respectively; P = .04). From the radiostereometric, radiographic, and clinical data, we conclude that the PFC-Sigma knee prosthesis can be used with confidence.

Unsuccessful use of a titanium mesh cage in ankle arthrodesis: a report on three cases operated on due to a failed ankle replacement.

Three patients with a failed total ankle arthroplasty underwent tibiocalcaneal arthrodesis. In an attempt to preserve leg length, a titanium cage filled with autologous bone was placed in the defect. None of the ankles healed primarily. After 9 to 29 months, the cages, which only contained necrotic material, were removed and repeat arthrodesis was performed using a retrograde intramedullary nail. After this procedure, 1 ankle had healed after 14 months whereas 2 did not heal. However, after a third attempt, using external fixation, 1 of the latter 2 healed. The method used in this report cannot be recommended. Although titanium mesh cages filled with autograft have been successfully used to substitute for vertebral defects, the author does not feel that the method can be recommended for ankle arthrodesis.

Age- and Gender-Specific Normative Values for the Self-Reported Foot and Ankle Score (SEFAS).

BACKGROUND: The Self-Reported Foot and Ankle Score (SEFAS) is a foot- and ankle-specific patient-reported outcome measurement (PROM) score that has been validated with good results for a variety of foot and ankle disorders. SEFAS is sensitive detecting improvement or deterioration after surgery. However, normative values, required to put a specific patient's summary score into perspective, are lacking. METHODS: In this report, we included 396 population-based men and 383 women (43% of the invited individuals), age 20-89 years, who had completed the SEFAS questionnaire and questions regarding anthropometrics and health. We used Mann-Whitney U test to test gender differences and Spearman correlation coefficients to determine any association between SEFAS score and age. We present gender-specific median SEFAS scores with range and 5th to 95th percentiles and mean with standard deviation. RESULTS: The SEFAS normative values were median 48 in men (range 11-48), 5th to 95th percentiles 31 to 48 and mean 45 ± 6, and in women, median 47 (range 6-48), 5th to 95th percentiles 23 to 48 and mean 43 ± 8 (gender comparison P < .001). SEFAS normative values correlated inversely with age (r = -0.12, P < .001). CONCLUSION: In the general population, older age was associated with lower SEFAS value, and men had higher values than women. The population-based normative SEFAS values provided in this study can facilitate quantification of disability related to foot and ankle with and without surgery in the foot and ankle. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Cross-linked N-telopeptide of type I collagen (NTx) in urine as a predictor of periprosthetic osteolysis.

Periprosthetic osteolysis is often nonsymptomatic and hard to visualize by conventional radiography. Cross-linked N-telopeptide of type I collagen (NTx), a marker of osteoclast mediated bone resorption, has been suggested to evaluate local particulate-induced osteolysis in patients operated on with a total hip prosthesis. Urine specimens were sampled after hip joint replacement in 160 patients. NTx was analyzed by a commercially available ELISA kit. Osteolysis was identified in the acetabulum and confirmed at operation. Using analysis of covariance to correct for differences in age, gender, and time after operation, NTx (mean SD) was 36+/-12 BCE/nM creatinine in patients with osteolysis (n=33) and 27+/-13 BCE/nM creatinine in patients without osteolysis (n=127) (p=0.003). Eighteen hips of 38 (47%), demonstrating an annual wear of more than 0.2 mm and an NTx value above 29 BCE/nM creatinine, had been revised due to osteolysis. The osteolysis prevalence in this group was increased 10 times (CI 4-23, p<0.05). Indeed, NTx release and annual wear were both associated with increased prevalence of osteolysis, however, independently of each other. NTx seems a feasible marker of periprosthetic osteolysis. A preoperative baseline NTx level is likely needed for its use as a predictor of periprosthetic osteolysis in individual cases.

Outcome After Salvage Arthrodesis for Failed Total Ankle Replacement.

BACKGROUND: In cases with total ankle replacement (TAR) failure, a decision between revision TAR and salvage arthrodesis (SA) must be made. In a previous study, we analyzed revision TAR and found low functional outcome and satisfaction. The aims of the current study were to analyze SA concerning failure rate and patient-related outcome measures (PROMs). METHODS: Until September 2014, a total of 1110 primary TARs were recorded in the Swedish Ankle Registry. Of the 188 failures, 118 were revised with SA (and 70 with revision TAR). Patient- and implant-specific data for SA cases were analyzed as well as arthrodesis techniques. Failure of SA was defined as repeat arthrodesis or amputation. Generic and region-specific PROMs of 68 patients alive with a solid unilateral SA performed more than 1 year before were analyzed. RESULTS: The first-attempt solid arthrodesis rate of SA was 90%. Overall, 25 of 53 (47%) patients were very satisfied or satisfied. Mean Self-reported Foot and Ankle Score (SEFAS) was 22 (95% confidence interval 20-24), Euro Qol-5 Dimensions 0.57 (0.49-0.65), Euro Qol-Visual Analogue Scale 59 (53-64), Short Form-36 physical 34 (31-37) and mental 50 (46-54). The scores and satisfaction were similar to those after revision TAR but the reoperation rate was significantly lower in SA (P < .05). CONCLUSION: Salvage arthrodesis after failed TAR had a solid arthrodesis rate of 90% at first attempt, but similar to revision TAR, less than 50% of the patients were satisfied and the functional scores were low. Until studies show true benefit of revision TAR over SA, we favor SA for failed TAR. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Survival Analysis of the Single- and Double-Coated STAR Ankle up to 20 Years: Long-Term Follow-up of 324 Cases From the Swedish Ankle Registry.

BACKGROUND: The Scandinavian Total Ankle Replacement (STAR) has been used widely in Europe and more recently in the United States. We studied the results of the single-coated and the double-coated STAR with long-term follow-up. METHODS: All STARs (n = 324) used in Sweden (first implanted in 1993) were included. Prosthetic survival was estimated according to Kaplan-Meier. RESULTS: The 14-year survival of the single-coated STAR was 0.47 (95% confidence interval [CI], 0.38-0.66), and the 12-year survival of the double-coated STAR was 0.64 (95% CI, 0.57-0.71). Women younger than 60 years with osteoarthritis had a statistically significantly higher risk of revision than men and than patients with other diagnoses. CONCLUSION: The long-term results of the STAR prosthesis are not encouraging. The results seem to deteriorate by time. LEVEL OF EVIDENCE: Level IV, retrospective case series.