Faculty Bibliography

BACKGROUND: Newer surgical approaches to THA, such as the direct anterior approach, may influence a patient's time to recovery, but it is important to make sure that these approaches do not compromise reconstructive safety or accuracy. QUESTIONS/PURPOSES: We compared the direct anterior approach and conventional posterior approach in terms of (1) recovery of hip function after primary THA, (2) general health outcomes, (3) operative time and surgical complications, and (4) accuracy of component placement. METHODS: In this prospective, comparative, nonrandomized study of 120 patients (60 direct anterior THA, 60 posterior THAs), we assessed functional recovery using the VAS pain score, timed up and go (TUG) test, motor component of the Functional Independence Measure (M-FIM), UCLA activity score, Harris hip score, and patient-maintained subjective milestone diary and general health outcome using SF-12 scores. Operative time, complications, and component placement were also compared. RESULTS: Functional recovery was faster in patients with the direct anterior approach on the basis of TUG and M-FIM up to 2 weeks; no differences were found in terms of the other metrics we used, and no differences were observed between groups beyond 6 weeks. General health outcomes, operative time, and complications were similar between groups. No clinically important differences were observed in terms of implant alignment. CONCLUSIONS: We observed very modest functional advantages early in recovery after direct anterior THA compared to posterior-approach THA. Randomized trials are needed to validate these findings, and these findings may not generalize well to lower-volume practice settings or to surgeons earlier in the learning curve of direct anterior THA. LEVEL OF EVIDENCE: Level II, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: Limb length discrepancy and its effects on patient function have been discussed in depth in the literature with respect to hip arthroplasty but there are few studies that have examined the effect on function of limb length discrepency following total knee arthroplasty (TKA). The aim of this study was to determine whether limb length discrepancy after TKA in patients with bilateral osteoarthritis of knee with varus deformity affects functional outcome. MATERIALS AND METHODS: Fifty-four patients with bilateral osteoarthritis of knee with varus deformity, who were operated for total knee arthroplasty from 1996 to 2008, were reviewed retrospectively. The patients were divided into two groups. Thirty patients (mean age 64 years) were operated for unilateral TKA and thirty patients (mean age 65.8 years) were operated for bilateral total knee arthroplasty. Six patients underwent staged surgery and were included in both groups as the time interval between the two surgeries was more than the minimum 6-month follow-up period specified for inclusion in the study. The limb length discrepancy was measured and statistically correlated with the functional component of the Knee Society Score. RESULT: In the unilateral group (n=30), the mean limb length discrepancy was 1.53 cm (range: 0-3 cm) and the mean functional score was 73 (range: 45-100). In the bilateral group (n=30), the mean limb length discrepancy was 0.5 cm (range: 0-2 cm) and the mean functional score was 80.67 (range: 0-100). A statistically significant negative correlation was found between limb length discrepancy and functional score in the unilateral group (Spearman correlation coefficient, r =-0.52, P=0.006), while no statistically significant correlation was found in the bilateral group (Spearman correlation coefficient, r = -0.141, P=0.458). CONCLUSION: Limb length discrepancy affects functional outcome after total knee arthroplasty, especially so in patients of bilateral osteoarthritis with varus deformity undergoing surgery of only one knee.