Minimum 19-Year Clinical Results and Patient Satisfaction After Total Knee Arthroplasty.

BACKGROUND: Long-term (minimum 19-year) outcome data on clinical results and patient satisfaction after posterior-stabilized total knee arthroplasties (TKAs) are missing in the literature. The purpose of the study was to evaluate the clinical and radiographic results as well as patient satisfaction at a mean of 21.2 years after posterior-stabilized TKAs. METHODS: This study included 756 patients (1,350 knees) who had undergone TKAs. There were 96 men and 660 women (mean age, 58 years; range, 40 to 84). The mean follow-up was 21.2 years (range, 19 to 23). At each follow-up visit, the patients were assessed radiographically and clinically. Furthermore, patient satisfaction was determined. RESULTS: The Knee Society total, pain, function, and deformity scores were 42, 18, 33, and 5 points, respectively, at the final follow-up. The mean Western Ontario and McMaster Universities Arthritis Index score was 25 points at the final follow-up. With revision or aseptic loosening as the end point, the 23-year intimated survival for the implant was 96% (95% confidence interval, 91 to 100%). The overall patient satisfaction score at the final follow-up was 83.3 points (range, 81 to 86). Patient satisfaction scores with regard to pain, housework, recreation, and surgery were 84, 81, 82, and 86 points, respectively. CONCLUSIONS: The findings of the present, mean 21-year follow-up clinical study suggest excellent results with regard to the revision rates and survivorship of the posterior-stabilized total knee implants. However, consistent with the literature, we found that about 80% of patients expressed overall satisfaction with their primary TKAs. About 8% of patients were either somewhat or very dissatisfied with the procedure.

Different Pattern of T-Score Discordance between Patients with Atypical Femoral Fracture and Femur Neck Fracture.

BACKGROUND: Our study evaluated the prevalence and pattern of T-score discordance between the spine and hip in Korean patients with atypical femoral fracture (AFF) and femur neck fracture (FNF). METHODS: A total of 49 patients (all women) who were treated for AFF and 1:3 matched 147 female patients with FNF were included from January 2012 to August 2022. A discordance of more than 1.5 between lumbar spine and femur neck bone mineral density (BMD) was defined as a difference and divided into 3 groups: lumbar low (LL; lumbar BMD is less than femur neck BMD), no discordance (ND), and femur neck low (FL; femur neck BMD is less than lumbar BMD). We compared the prevalence and pattern of discordance between 2 groups, and the associated risk factors of T-score discordance among the subjects were evaluated using regression analysis. RESULTS: The prevalence of discordance was significantly higher in patients with AFF (51%) than in those with FNF (25.2%; p<0.001). LL discordance was found in 46.9% of the patients with AFF but only 4.8% in those with FNF. Conversely, FL discordance was found in 4.1% of the patients with AFF and 20.4% in those with FNF, respectively. No specific risk factor was found as T-score discordance in the 2 groups. CONCLUSIONS: Clinicians should be aware that the pattern of T-score discordance can vary depending on the location of osteoporotic fractures. In addition, a longitudinal study would be necessary to verify the pattern of T-score discordance related to the osteoporotic fracture location.

Minimum 30-Year Results of Bilaterally Implanted Cemented and Cementless Total Hip Arthroplasty in Patients Younger Than 50 Years.

BACKGROUND: The rate of failure of cemented and cementless total hip arthroplasty (THA) in younger patients is higher than that in elderly patients. The purpose of this study is to document the long-term clinical results of THA with the so-called third-generation cementing and the results of second-generation cementless THA in patients <50 years of age. METHODS: This study included 106 patients who had had bilateral THA with a cemented stem in one hip and a cementless stem in the other. There were 78 men and 28 women. Their mean age was 47 years (range, 21-49). The average follow-up duration was 31 years (range, 30-32.5). RESULTS: There were similar mean Harris Hip Scores (90 versus 91 points) between the groups at the final follow-up. Forty-six acetabular components (43%) in the cemented group and 48 acetabular components (45%) in the cementless group were revised. Five femoral components (5%) in the cemented group and 4 femoral components (4%) in the cementless group were revised. Survivorship of the acetabular component at 30.8 years was similar in both groups (57% in the cemented group versus 55% in the cementless group). Survivorship of the femoral component at 30.8 years was also similar in both groups (95% in the cemented group versus 96% in the cementless group). CONCLUSION: Long-term fixation of the cemented or cementless femoral stem was outstanding. There was a high rate of the acetabular component revision due to conventional polyethylene wear and periacetabular osteolysis in both hybrid and fully cementless THA groups.

Is Highly Cross-Linked Polyethylene Safe for Use in High-Flexion Posterior Stabilized Total Knee Arthroplasty?

BACKGROUND: Application of highly cross-linked polyethylene (HXLPE) to a posterior cruciate-substituting total knee arthroplasty (TKA) might add the risk of fracture and failure of the tibial polyethylene insert. The purpose of this study is to evaluate the long-term (up to 19 years) clinical and radiographic results of posterior cruciate-substituting TKAs with HXLPE or conventional polyethylene. METHODS: This study analyzed the results of 1,217 patients (444 men and 773 women; mean age of 65 ± 7 years, range, 31-85) (2,434 knees) who had received a NexGen LPS-Flex prosthesis with a conventional tibial insert in one knee and the same prosthesis with an HXLPE tibial insert in the contralateral knee. The mean duration of follow-up was 17 years (range, 15-19). RESULTS: The 2 groups did not differ significantly (P > .05) with regard to the clinical and radiographic results. No knee in either group had a fracture of the tibial polyethylene post or failure of the locking mechanism of the tibial polyethylene insert or osteolysis. Twenty-eight knees (2.3%) in the HXLPE group and 26 knees (2.1%) in the conventional polyethylene group were revised. The estimated survival rate at 17 years was 97.7% in the HXLPE group and 97.9% in the conventional polyethylene group. CONCLUSION: The data suggest that clinical and radiographic findings at a mean of 17 years after posterior cruciate-substituting TKA are the same for patients treated with HXLPE and those treated with conventional polyethylene.

Long-Term Results (Minimum of 20 Years) of a Pure Proximal-Loading Metaphyseal-Fitting Anatomic Cementless Stem Without Distal Stem Fixation in Hip Arthroplasty.

BACKGROUND: There are no reported results for more than 20 years of a pure proximal-loading anatomic cementless femoral stem without diaphyseal stem fixation. The purpose of this study was to evaluate the long-term (minimum 20 years) clinical results, bone remodeling, revision rate, and survivorship of these implants in patients aged less than 60 years. METHODS: We included 523 patients (657 hips), including 319 men and 204 women. The mean body mass index was 26.7 (range, 23-29 kg/m2). The mean age of patients at index surgery was 55 years (range, 20-59 years). The Harris Hip Score, the Western Ontario and McMaster Universities Osteoarthritis Index, and the University of California, Los Angeles activity score were recorded preoperatively and at each follow-up. Mean follow-up was 23.5 years (range, 20-27 years). RESULTS: The Harris Hip Score at the final follow-up was a mean 93 points (range, 70-100 points). The Western Ontario and McMaster Universities Osteoarthritis Index and University of California, Los Angeles activity scores at the final follow-up were 16 and 7.6 points, respectively. Five femoral components (0.8%) and 13 acetabular components (2.0%) were revised. All cases in the current series had grade 2 stress shielding; no hips had grade 3 or 4 stress shielding. Kaplan-Meier survivorship of the implants at 23.5 years was 98.0% (95% confidence interval 92%-100%) for the acetabular component and 99.2% (95% confidence interval 93%-100%) for the femoral component. CONCLUSION: A pure proximal-loading metaphyseal-fitting anatomic cementless stem with alumina-on-alumina ceramic bearing couples functioned well, with no osteolysis or mild stress-shielding at an average 23.5-year follow-up.

Does an Ultra-Short Anatomic Cementless Femoral Stem Improve Long-Term (Up to 17 Years) Results in Patients Younger Than 30 Years?

BACKGROUND: The purpose of this long-term (up to 17 years) follow-up study was to determine: (1) clinical results and evidence of clicking or squeaking sounds; (2) radiographic results, including rates of osseointegration, bone remodeling, and osteolysis; (3) rates of complications including thigh pain, periprosthetic fracture, and ceramic fracture; (4) rates of revision; and (5) survival rates of implants in patients younger than 30 years. METHODS: We analyzed the results of 240 consecutive primary total hip arthroplasty in 180 patients (118 men and 62 women who had a mean age of 27 years (range, 21 to 30 years)). The mean follow-up was 16 years (range, 14 to 17 years). RESULTS: Mean Harris hip score, Western Ontario and McMaster Universities score, and University of California, Los Angeles activity score were 93 points, 18 points, and 7 points, respectively, at final follow-up. Radiographically, all of the acetabular components and all but two femoral components were well-fixed at the final follow-up. No hip had osteolysis or exhibited Grade 3 stress shielding. All but two patients had no groin or thigh pain. No hip had a periprosthetic or ceramic fracture. Eight hips (3%) exhibited squeaking sounds. Two acetabular components and two femoral stems were revised. The survival of the acetabular and femoral component was 99.2% (95% confidence interval, 94 to 100%). CONCLUSION: The results of the present long-term study of ultra-short anatomic cementless femoral stems suggest excellent clinical and radiographic results in patients younger than 30 years.

Long-Term (up to 38 Years) Failure Modes of Total Hip Arthroplasty in Adult Patients Who Had Childhood Infection of Hip.

BACKGROUND: The long-term failure modes of total hip arthroplasty (THA) in adult patients who had childhood infection have not been documented. The purpose of this study is to analyze the longer term clinical and radiographic results, prevalence of osteolysis, and survival rate of THA. METHODS: We reviewed the results of 142 patients (145 hips) (mean age 41.9 years). The age of the patients at the time that the infection was contracted was an average of 7.1 years (range 1-11). The average interval between active infection and THA was 34.5 years. All but 2 hips (1 patient) had a quiescent period of infection of more than 10 years. The average duration of follow-up after THA was 31.5 years (range 25-38). RESULTS: All but 2 hips with more than 10 years of quiescent infection had no recurrence of infection. The remaining 2 hips in the 1 patient with only 7 years of quiescent infection had a recurrence of infection. Seventy-eight of 145 hips (54%) underwent isolated cup revision for loosening, or osteolysis, or dislocation. Thirty (21%) femoral components were revised for aseptic loosening and/or osteolysis. The Kaplan-Meier survivorship curve at 31.5 years showed that the survival rate of the acetabular component was 46% (95% confidence interval 39-74) and that of the femoral component was 79% (95% confidence interval 73-89). CONCLUSION: Contributing factors to the high failure rate of THAs were less than optimal prostheses and poor quality of polyethylene during the time period of this study.

Long-Term Follow-Up of Management of the Hypoplastic Femur With Femoral Episiotomy and Onlay Allograft During Total Hip Arthroplasty.

BACKGROUND: To insert the regular-sized stem for a dysplastic femoral canal, controlled episiotomy of the femur can be performed. The purpose of this study is to determine the long-term (up to 19 years) results of total hip arthroplasties (THAs) using strut allografts combined with an episiotomy over an extensively porous-coated stem. METHODS: We reviewed the results of 65 total hip arthroplasties in 63 patients (mean age 42.1 years; range 21-61) with dysplastic femur after childhood sepsis. The patients were treated using controlled episiotomy of the femur to widen the femoral canal, extensively porous-coated femoral stems, and cortical strut allografts because primary axial or rotational stability could not be achieved without grafting. The mean follow-up was 17.1 years (range 15-19). RESULTS: The mean Harris Hip Score at the final follow-up was 85 ± 15 points (range 45-100). The mean Western Ontario and McMaster Universities Osteoarthritis Index score was 23 ± 15 points (range 13-53). The mean University of California, Los Angeles score was 6.3 points (range 5-8). A Kaplan-Meier survivorship analysis at 19 years of follow-up showed that the survival rate of the femoral components was 92% (95% confidence interval 89-98), and it was 88% (95% confidence interval 85-92) for the acetabular component with aseptic loosening or revision for any reason. CONCLUSION: We found good results in terms of longevity and functional outcome using this technique. Future mechanical studies, in addition to controlled clinical studies, are warranted.

Extracellular vesicles from tonsil­derived mesenchymal stromal cells show anti­tumor effect via miR­199a­3p.

Mesenchymal stem cells (MSCs) are mesoderm­originated adult SCs that possess multidirectional differentiation potential. MSCs migrate to injured tissue and secrete a range of paracrine factors that induce regeneration in damaged tissue and exert immune modulation. Because tumor progression is dependent on cross­talk between the tumor and its microenvironment, MSCs also produce extracellular vesicles (EVs) that mediate information transfer in the tumor microenvironment. However, the effect of MSC­derived EVs on tumor development and progression is still controversial. To date, tonsil­derived MSCs (T­MSCs) have been shown to possess all the defined characteristics of MSCs and show distinctive features of differential potential and immune modulation. To observe the effect of soluble mediators from T­MSCs on tumor growth, human liver cancer cell line (HepG2) cells were injected into nude mice and HepG2 cell scratch migration assay was performed using conditioned medium (CM) of T­MSCs. T­MSC CM inhibited tumor growth and progression and it was hypothesized that EVs from T­MSCs could inhibit tumor progression. microRNA (miRNA or miR) sequencing using five different origins of T­MSC­derived EVs was performed and highly expressed miRNAs, such as miR­199a­3p, miR­214­3p, miR­199a­5p and miR­199b­5p, were selected. T­MSCs inhibited tumor growth and HepG2 cell migration, potentially via miR­199a­3p targeting CD151, integrin α3 and 6 in HepG2 cells.

Combined Strut Onlay Allografting, Reduction Osteotomy, and Extensively Porous-Coated Stem for Reconstruction of Severe Femoral Defects During Revision Hip Arthroplasty.

BACKGROUND: The purpose of this study is to determine the long-term (up to 27 years) results of a modified technique applying strut allografts combined with a reduction osteotomy over an extensively porous-coated stem. METHODS: We reviewed the results of 399 revision total hip arthroplasties (for aseptic loosening in 390 hips and septic loosening in 9 hips) in 369 patients (mean age 58 ± 13 years, range 22-65) performed with an extensively porous-coated femoral stem combined with a cortical strut onlay allograft. The mean follow-up was 23 years (range 20-27). RESULTS: The mean Harris Hip Score was 84 ± 16 points (range 35-100) at the final follow-up. The mean Western Ontario and McMaster Universities Osteoarthritis Index score was 21 ± 16 points (range 12-53) at the final follow-up. The mean University of California Los Angeles activity score was 6.1 points (range 5-8). A Kaplan-Meier survivorship analysis at 23 years of follow-up showed that the survival rate of the femoral component was 95.5% (95% confidence interval 89-98) with aseptic loosening or revision for any reason and it was 91.5% (95% confidence interval 85-95) if septic loosening was included. CONCLUSION: We found good results in terms of longevity and functional outcome using this modified technique. Future mechanical studies in addition to controlled clinical studies are warranted.

20-Year Minimum Outcomes and Survival Rate of High-Flexion Versus Standard Total Knee Arthroplasty.

BACKGROUND: There are conflicting reports of early and mid-term results of the high-flexion total knee arthroplasties (TKAs). The purpose of the present long-term follow-up study was to determine the long-term (minimum 20 years) clinical and radiographic and CT scan results, and the survival rates of high-flexion versus standard TKAs. METHODS: Ninety-five patients (190 knees) were included (mean age, 65 ± 6.5 years). The mean follow-up was 20.3 years (range, 20 to 20.6 years). RESULTS: Revision of the TKA was performed in 5 knees (5.2%) with high-flexion TKA and in 3 knees (3.2%) with standard TKA. The rate of survival at 20 years was 94.8% (95% CI, 91%-98%) in the high-flexion TKA group and 96.8% (95% CI, 92%-100%) in the standard TKA group with reoperation for any reason. No knee had osteolysis in either group. CONCLUSIONS: At this length of follow-up, high-flexion TKA has comparable outcomes and survivorship to standard TKA.

The 22 to 25-Year Survival of Cemented and Cementless Total Knee Arthroplasty in Young Patients.

BACKGROUND: Despite cementless total knee arthroplasties (TKAs) have potential advantages over cemented TKAs, there are conflicting results. The purpose of the present study is to determine the long-term clinical and radiographic results, the survival rate, and the prevalence of osteolysis of cemented vs cementless TKAs. METHODS: A total of 261 patients (522 knees) who underwent bilateral simultaneous TKAs were included in the present study (mean age, 62.5 ± 5.5 years). Patients were evaluated clinically, radiographically, and also using computed tomography scans. A mean follow-up period was 23.8 years (range, 22-25 years). RESULTS: There were no significant differences between the Knee Society total score, change in total score, knee function score, and Western Ontario and McMaster Universities Osteoarthritis Index score in the 2 groups. In total, 8 knees (3%) were revised in the cementless group and 5 knees (2%) in the cemented group. Radiographs and computed tomography scans showed no femoral, tibial, or patellar osteolysis in either group. The rate of survival at 25 years was 97% (95% confidence interval [CI], 92%-100%) in the cementless group and 98% (95% CI, 94%-100%) in the cemented group, with reoperation for any reason as the end point. The rate of survival at 25 years was 98% (95% CI, 94%-100%), with reoperation for aseptic loosening as the end point in both groups. CONCLUSIONS: At this length of follow-up, cementless TKA has comparable outcomes and survivorship to cemented TKA.

Long-term result of a second or third two-stage revision total knee arthroplasty for infected total knee arthroplasty.

BACKGROUND: Persistent or recurrent infection after two-stage revision total knee arthroplasty (TKA) for the treatment of an infected TKA is a dreaded complication. The purpose of the current study was to determine the ability of a second or third two-stage revision TKA to control infection, evaluate the long-term survivorship of the TKA prosthesis, and measure the functional outcome after a second or third two-stage revision TKA for reinfection. METHODS: We evaluated 63 patients (65 knees) with failed two-stage TKA treated with a second or a third two-stage revision TKA. There were 25 men and 38 women (mean age, 67 ± 10.2 years). The mean follow-up from the time of a second two-stage TKA revision was 15.1 years (range, 10 to 19 years) and the mean follow-up from the time of a third two-stage TKA revision was 7 years (range, 5 to 10 years). RESULTS: Overall, infection was successfully controlled in 49 (78%) of 65 knees after a second two-stage revision TKA was performed. In the remaining 16 knees, recurrent infection was successfully controlled in 12 knees (75%) after a third two-stage revision TKA. Survivorship, free of implant removal for recurrent infection, was 94% at 15.1 years (95% CI, 91 to 100%). Survival free of revision TKA for mechanical failure was 95% (95% CI, 92 to 100%). CONCLUSIONS: The results of the current study suggest that a second or a third two-stage revision TKA is a reasonable option for controlling infection, relieving pain, and achieving a satisfactory level of function for patients with infected TKAs.

Long-Term Survival (up to 34 Years) of Retained Cementless Anatomic Femoral Stem in Patients <50 Years Old.

BACKGROUND: There is a paucity of studies longer than 30 years to determine clinical and radiographic results of retained cementless anatomic stem. The purpose of this study is to determine the long-term (up to 34 years) survival rate of the retained cementless anatomic femoral stem in patients <50 years of age. METHODS: Isolated cup revision was performed with retaining primary cementless anatomic femoral stem in 206 patients (149 men and 57 women). Clinical and radiographic results were monitored at each follow-up. At the latest follow-up, computed tomography scans were carried out in all hips to determine the prevalence of osteolysis. The mean follow-up of the retained femoral stem was 30.3 years (range 27-34). The mean follow-up of the revised cup was 25.5 years (range 22-29). RESULTS: The mean Harris Hip Score was 91 ± 7.8 points (range 71-100) and the mean Western Ontario and McMaster Universities Osteoarthritis score was 16 ± 7 points (range 7-34) at the final follow-up. The mean University of California, Los Angeles activity score was 7 ± 4 points (range 5-10) at the final follow-up. The overall survival rate of retained cementless femoral stems was 98.9% (95% confidence interval 91-100) at 30.3 years. The survival rate of the revised cup was 93% (95% confidence interval 89-98) at 25.5 years. CONCLUSION: The rate of aseptic loosening of already osseointegrated femoral stem remains low with ceramic-on-ceramic bearing in young active patients.

Long-Term (Up to 27 Years) Prospective, Randomized Study of Mobile-Bearing and Fixed-Bearing Total Knee Arthroplasties in Patients <60 Years of Age With Osteoarthritis.

BACKGROUND: Our study determined long-term (up to 27 years) results of fixed-bearing vs mobile-bearing total knee arthroplasties (TKAs) in patients <60 years with osteoarthritis. METHODS: This study included 291 patients (582 knees; mean age 58 ± 5 years), who received a mobile-bearing TKA in one knee and a fixed-bearing TKA in the other. The mean duration of follow-up was 26.3 y (range 24-27). RESULTS: At the latest follow-up, the mean Knee Society knee scores (91 ± 9 vs 89 ± 11 points, P = .383), Western Ontario and McMaster Universities Osteoarthritis Index (35 ± 7 vs 37 ± 6 points, P = .165), range of knee motion (128° ± 13° vs 125° ± 15°, P = .898), and University of California, Los Angeles activity score (6 ± 4 vs 6 ± 4 points, P = 1.000) were below the level of clinical significance between the 2 groups. Revision of mobile-bearing and fixed-bearing TKA occurred in 16 (5.5%) and 20 knees (6.9%), respectively. The rate of survival at 27 years for mobile-bearing and fixed-bearing TKA was 94.5% (95% confidence interval 89-100) and 93.1% (95% confidence interval 88-98), respectively, and no significant differences were observed between the groups. Osteolysis was identified in 4 knees (1.4%) in each group. CONCLUSION: There were no significant differences in functional outcomes, rate of loosening, osteolysis, or survivorship between the 2 groups.

Eighteen-Year Results of Cementless THA with Alumina-on-HXLPE Bearings in Patients <30 Years Old: A Concise Follow-up of a Previous Report.

Despite overall good survivorship and clinical outcomes in the short term after total hip arthroplasty (THA) with use of alumina ceramic-on-highly cross-linked polyethylene (HXLPE) in patients younger than 30 years of age, there is a paucity of long-term data to evaluate the fixation of the components and the prevalence of osteolysis. We reviewed the records of 45 patients (54 hips) who had been included in a previous report to evaluate the long-term functional outcomes as well as radiographic and computed tomographic scan findings (particularly with regard to component fixation and osteolysis) after a mean duration of follow-up of 17.8 years. One femoral stem was revised because of aseptic loosening, and 2 acetabular components were revised because of recurrent dislocation. The survival rate at 17.8 years was 98% for the femoral component and 96% for the acetabular component. LEVEL OF EVIDENCE:: Therapeutic Level IV. See Instructions for Authors for a complete description of level of evidence.

Long-Term Assessment of Highly Cross-Linked and Compression-Molded Polyethylene Inserts for Posterior Cruciate-Substituting TKA in Young Patients: A Concise Follow-up of a Previous Report.

The purpose of the present study was to determine the long-term clinical and radiographic results, survival rate, prevalence of osteolysis, and prevalence of fracture of the tibial polyethylene insert following total knee arthroplasty (TKA). Three hundred patients (600 knees) were included in this follow-up study. The mean age of the patients (and standard deviation) was 60.3 ± 4.3 years, and the mean duration of follow-up was 13.2 years (range, 12 to 14 years). Revision of the TKA prosthesis was performed in 7 knees (2.3%) with a compression-molded polyethylene (CPE) tibial insert and 6 knees (2%) with a highly cross-linked polyethylene (HXLPE) tibial insert. The rate of survival at 14 years was 97.7% (95% confidence interval [CI], 94%-100%) in the CPE group and 98% (95% CI, 94%-100%) in the HXLPE group with reoperation for any reason as the end point. The rate of survival at 14 years was 98% (95% CI, 94%-100%) in both groups with reoperation for mechanical failure as the end point. No knee had osteolysis or fracture of the tibial polyethylene insert. There were no between-group differences. LEVEL OF EVIDENCE:: Therapeutic Level I. See Instruction for Authors for a complete description of levels of evidence.

Long-Term (Up to 21 Years) Survival of Revision Total Knee Arthroplasty with Use of a Constrained Condylar Knee Prosthesis: A Concise Follow-up of a Previous Report.

In our original report, 97 patients (114 knees) underwent revision total knee arthroplasty with use of a Legacy Constrained Condylar Knee prosthesis (LCCK; Zimmer), with a mean follow-up of 7.2 years (range, 5 to 10 years). The purpose of the present study was to determine the long-term clinical and radiographic results, with a focus on component fixation and the prevalence of osteolysis. At a mean follow-up of 19.2 years (range, 16 to 21 years), re-revision of the LCCK prosthesis had been performed in 10 knees (9%). The rate of survival at 19.2 years was 96% (95% confidence interval [CI], 94% to 100%) with reoperation for mechanical failure as the end point, and 91% (95% CI, 87% to 98%) with reoperation for any reason as the end point. One knee had circumferential osteolysis around the components. LEVEL OF EVIDENCE:: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.