Gender differences in femoral component fit and clinical outcomes with unisex total knee prosthesis / 中华骨科杂志

ABSTRACT

Objective To determine the effects of gender on distal femoral aspect ratio (DFAR),femoral component fit,and clinical outcomes at 2 years after total knee arthroplasty (TKA).Methods From December 2012 to December 2014,the clinical and radiographic characteristics of 107 consecutive patients (109 knees) were studied prospectively.All patients were divided into two groups according to gender33 cases (33 knees) were male and 74 cases (76 knees) were female.These subjectives underwent unilateral primary TKAs for end-stage osteoarthritis by using Vanguard high-flex open-box posterior-stabilized fixed-bearing prosthesis.The anterior-posterior size increment of the Vanguard femoral components was 2 mm.The clinical outcomes (Knee Society Score,Western Ontario and McMasters University osteoarthritis index,time-up-to-go test,chair rise test,stair-climbing test,range of flexion,extensor lag,flexion contracture,anterior knee pain score and patient satisfaction) between two groups were compared at 2 years postoperatively.The femoral component fit and two kinds of DFARs were also compared intraoperatively.Results The total overhang value in zone 2 was-5.51±4.46 mm in male and-3.24±3.93 mm in female,respectively.That in zone 3 was-5.99±4.73 mm in male and-3.45±3.98 mm in female.The total underhang value in male was significantly higher than that in female (P＜0.05).The rate of significant underhang in zone 3 was significantly higher in male than that in female (60.6％,23.7％,P＜O.05).Two kinds of DFARs in male were significantly higher than those in female (1.56±0.12 vs.1.51±0.12,1.28±0.08 vs.1.24±0.11,P＜0.05).Compared with intra-operative range of flexion (ROF) in the condition of 90° hip flexion after prosthesis implantation,the loss of ROF against gravity and the loss of passive ROF at 2 years postoperatively were statistically significant higher than those in female (-8.73°±7.71° vs.-4.82°±6.67°,-11.45°±8.78° vs.-7.34°±8.71°,P＜0.05).In the male group,the natural ROF after capsule closed (132.85°±6.01°) was significantly larger than that of the female group (128.78°±6.34°),but there was no significant difference in passive flexion.The change of non-weight-bearing passive ROF (1.67°± 14.76°),the Knee Society stairclimbing score (45.15±7.12) and the proportion of being able to squat and rise (97.0％) in male group were greater than those in female group,postoperatively.Conclusion Although DFAR is different within gender;it has little effects on early outcomes after unisex posterior-stabilized TKA.The loss of ROF in male is more prominent than that in female.Increased size offerings of femoral components improve fit in female distal femur.However,distal femur of male still exist obvious underhang.