Functional Outcome and Revision Rate Are Independent of Limb Alignment Following Oxford Medial Unicompartmental Knee Replacement.

BACKGROUND: There is controversy about optimal limb alignment following knee replacement. An aim of using Oxford medial unicompartmental knee replacement (UKR) implants is to accurately restore normal ligament tension in the knee, thereby restoring normal kinematics. This return to normal tension typically results in a return to prearthritic alignment, which is frequently varus. The aim of this study was to investigate the relationship between postoperative limb alignment and postoperative patient-reported outcome and implant revision rate. METHODS: We used a consecutive cohort of 891 knees with cemented Oxford medial UKR implants with a mean 10-year follow-up and recorded alignment. We grouped knees according to postoperative mechanical alignment as marked varus (estimated at 10°), mild varus (estimated at 5°), neutral, and valgus. The mean Oxford Knee Score (OKS) was calculated at 5 and 10 years postoperatively. Revision risk was assessed by survival analysis and component-time incidence rates. RESULTS: Postoperatively, 67 (8%) of the 891 knees were in marked varus; 308 (35%), in mild varus; 508 (57%), in neutral; and 8 (1%), in valgus. The valgus group (8 knees) was too small for further analysis. The mean OKS (and standard deviation [SD]) at 10 years postoperatively was 41.7 ± 7 for marked varus, 40.5 ± 8 for mild varus, and 39.4 ± 9 for neutral alignment (p = 0.28). At 10 years, 92%, 85%, and 76% achieved a good or excellent OKS outcome, respectively (p = 0.02). Twelve-year survival rates were 93.3% for marked varus, 93.2% for mild varus, and 93.6% for neutral alignment, respectively (p = 0.53). Revision incidence rates per 100 component-years were 0.49 (95% confidence interval [CI], 0.2 to 1.5), 0.36 (95% CI, 0.2 to 0.7), and 0.54 (95% CI, 0.4 to 0.8), respectively, and were not significantly different (p = 0.53). CONCLUSIONS: Marked postoperative varus mechanical alignment of an estimated 10° was present in 8%, and mild varus of about 5° was present in 35%. Increasing varus alignment was associated with an increasing percentage of good or excellent OKS outcomes, but otherwise there were no significant differences between alignment groups in patient-reported outcome or revision rate. These data support the standard operative technique for the Oxford UKR, which aims to restore ligament tension and therefore prearthritic alignment rather than neutral mechanical alignment. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Total hip arthroplasty versus hemiarthroplasty for displaced femoral neck fractures: meta-analysis of randomized trials.

BACKGROUND: Most patients with displaced femoral neck fractures are treated by THA and hemiarthroplasty, but it remains uncertain which if either is associated with better function and lower risks of complications. QUESTIONS/PURPOSES: We performed a meta-analysis of randomized controlled trials (RCTs) to determine whether THA was associated with lower rates of reoperations, mortality, complications, and better function compared with hemiarthroplasty. METHODS: We searched the PubMed, Embase, Chinese Biomedicine Literature, and Cochrane Register of Controlled Trials databases and identified 12 RCTs (including a total of 1320 patients) for meta-analysis. Risk ratios (RRs) and weighted mean differences (WMDs) from each trial were pooled using random-effects or fixed-effects models depending on the heterogeneity of the included studies. RESULTS: THA was associated with a lower risk of subsequent reoperations compared with hemiarthroplasty (RR = 0.53; 95% CI, 0.34-0.84). There was no difference in mortality between patients undergoing THA and hemiarthroplasty (RR = 0.81; 95% CI, 0.60-1.09). For complications, there was a higher risk of dislocation in patients undergoing THA (RR = 1.99; 95% CI, 1.26-3.15), but there were no differences in local infections (RR = 1.60; 95% CI, 0.74-3.46) and general complications (RR = 1.15; 95% CI, 0.91-1.45). Patients with THA had higher Harris hip scores at 1 year (WMD = 3.81; 95% CI, 0.87-6.74) and at 3 or 4 years (WMD = 10.07; 95% CI, 6.92-13.21). CONCLUSIONS: Despite more dislocations, THA can benefit patients with displaced femoral neck fractures with a lower reoperation rate and higher functional scores.

Revision total knee arthroplasty with modular components inserted with metaphyseal cement and stems without cement.

The clinical and radiographic outcomes of 50 consecutive revision total knee arthroplasties in 47 patients, placed with metaphyseal cemented femoral and tibial components with press-fit cementless stems, were reviewed at 36-month average follow-up. Revision was performed for aseptic loosening (11/50), infection (17/50), periprosthetic fracture (8/50), component failure (6/50), instability (6/50), and malalignment (2/50). The press-fit cementless stems were 80 to 160 mm in length and tightly contacted the endosteum of the metadiaphyseal areas. Four (9%) knees were re-revised for infection, zero for aseptic loosening. The average modified Hospital for Special Surgery knee score improved from 49 to 87. One patient (2%) reported thigh pain, and 1 reported leg pain. Metaphyseal cemented revision total knee components with press-fit cementless femoral and tibial stems were not associated with significant thigh and leg pain.

[Current status of valgus angle, tibial head closing wedge osteotomy in media gonarthrosis]. / Der Stellenwert der valgisierenden, zuklappenden Tibiakopfosteotomie bei der medialen Gonarthrose.

In young and active patients, closing-wedge high tibial osteotomies are reliable procedures in the treatment of osteoarthritis of the medial compartment of the knee. This has been consistently shown throughout the last 2 decades. The present study analyzes the long-term results of 217 patients after an average of 9 years and compares them to the results in the literature. Besides correction of the alignment, other prognostic factors such as the patients' age, overweight, the preoperative degree of osteoarthritis, but also a newer prognostic factor described by the Lyon knee school have been evaluated. The authors found that the "tibial bone varus angle" might be helpful to differentiate between a bony deformity of the proximal tibia, amenable to correction by osteotomy, and a secondary bony erosion of the medial tibial plateau, with a worse prognosis.