Objective To investigate the effects of altering the femoral offset after total hip arthroplasty on postoperative pain and function. Methods A total of 162 patients undergoing single total hip arthroplasty between March 2009 and December 2011 met the inclusion criteria. According to difference of femoral offset between operative side and contralateral side, the patients were divided into 3 groups: decreased offset group (lt; — 5 mm, 30 cases), normal offset group ( — 5-5 mm, 87 cases), and increased offset group (gt; 5 mm, 45 cases). There was no significant difference in gender, age, and disease duration among 3 groups (P gt; 0.05). The types of femoral stem and head prosthesis were compared among 3 groups. Short Form 12 Health Survey (SF-12) score, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score, and Harris score were used to evaluate the clinical outcomes. Results Standard offset femoral prosthesis was most used, followed by increased offset femoral prosthesis, and decreased offset femoral prosthesis was least in 3 groups. The types of femoral stem and head prosthesis showed no significant difference among 3 groups (P gt; 0.05). The patients were followed up 12-33 months (mean, 25 months). There was no significant difference in SF-12 score among 3 groups at 1 year after operation (P gt; 0.05); there was no significant difference in WOMAC pain and stiffness scores among 3 groups (P gt; 0.05) except WOMAC body function score (P lt; 0.05). According to Harris scoring criteria, the results were excellent in 13 cases, good in 8 cases, fair in 7 cases, and poor in 2 cases in decreased offset group; the results were excellent in 42 cases, good in 34 cases, fair in 9 cases, and poor in 2 cases in normal offset group; the results were excellent in 31 cases, good in 12 cases, and fair in 2 cases in increased offset group; and significant difference was found among 3 groups (Z= — 3.152, P=0.008). Conclusion Increased offset is more conducive to joint functional recovery and pain relief; decreased offset may lead to joint function deterioration and pain aggravation.
Objective To investigate the effect of femoral offset reconstruction on pelvic stabil ity during gait after total hip arthroplasty. Methods According to the inclusion criteria, 29 patients undergoing unilateral total hip arthroplasty between January 2000 and December 2005 were selected. There were 10 males and 19 females with an average age of 64.3 years (range, 33-75 years). The affected hips included 15 left hips and 14 right hips. The follow-up time was from 5 to 10 years (mean, 7.7 years). The Harris score was 90 to 100 (mean, 97) at last follow-up. The femoral offset ratio (FOR) was calculated by measuring the femoral offset of the bilateral hips on radiograph, and then the patients were divided into 2 groups: group A (the femoral offset of diseased hip was less than that of normal hip, n=10) and group B (the femoral offset of diseased hip was greater than that of normal hip, n=19). The pelvis kinematic variables were measured by three-dimensional gait analysis to collect the magnitude of pelvic obl ique angle (POA). Results In group A, the FOR was 0.81 ± 0.08 and the POA was (—0.42 ± 0.91)°. In group B, the FOR was 1.27 ± 0.15 and the POA was (1.02 ± 0.94)°. For the normal hip, the POA was (1.15 ± 0.85)°. The POA was significantly less in group A than in group B and the normal l imb (P lt; 0.05). The difference in POA had no significance between group B and the normal hip (P gt; 0.05). The POA was positive relative with FOR (r=0.534, P=0.003), and the regression equation was y= — 2.551+ 2.781x. Conclusion The femoral offset reconstruction is crucial to improve hip abductor function and gait.