Arthroscopic offset restoration in femoroacetabular cam impingement: accuracy and early clinical outcome.

PURPOSE: The purpose of this study was to determine the accuracy of arthroscopic restoration of femoral offset as well as the early clinical outcome of arthroscopic debridement and femoral offset restoration and whether there is a correlation between accuracy and outcome. METHODS: Twenty-two patients with symptomatic femoroacetabular cam impingement underwent arthroscopic correction of the femoral offset and debridement. The alpha angle was measured with magnetic resonance imaging preoperatively and postoperatively for quantification of the offset, and the clinical status was determined by documenting the impingement sign, range of motion, intensity of pain on a visual analog scale, Nonarthritic Hip Score, and complications preoperatively and 6 months postoperatively. RESULTS: The alpha angle improved from a mean of 75 degrees to 54 degrees. Internal rotation increased from a mean of 5 degrees to 22 degrees, flexion increased from a mean of 107 degrees to 124 degrees, and the pain score decreased from a mean of 5.8 to 1.4. The Nonarthritic Hip Score increased from a mean of 49 to 74 points. No major complications were encountered. Patients with early osteoarthritis did substantially worse than those without it. The alpha angle did not correlate with any clinical outcome measure. CONCLUSIONS: The femoral offset can be precisely restored via an arthroscopic technique in the treatment of femoroacetabular cam impingement. The early clinical outcome of arthroscopic offset restoration and debridement is good in patients with no or only mild osteoarthritis. The accuracy of correction is not correlated with the early clinical outcome. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

The clinical consequences of flexion gap asymmetry in total knee arthroplasty.

This study was carried out to compare femoral component rotation of 18 knees from 18 patients who suffered from lateral flexion instability after total knee arthroplasty (Western Ontario and McMaster University Osteoarthritis [WOMAC], 6.4 points; International Knee Society [IKS] score, 119 points) with 10 asymptomatic controls (WOMAC, 0.1 points; IKS score, 182 points) after total knee arthroplasty. The symptomatic patients showed increased lateral joint laxity as determined by fluoroscopic stress radiography. Femoral component rotation was determined by computed tomography scans. The femoral component rotation was more internally rotated in symptomatic patients (5.5 degrees ) than in controls (1.0 degrees ) (P = .04). Varus laxity in flexion was higher in symptomatic patients (11.0 degrees ) than in controls (7.0 degrees ) (P < .001). Increased lateral flexion laxity is associated with increased internal femoral component rotation and a less favorable clinical outcome.

Failure of reinserted short external rotator muscles after total hip arthroplasty.

The frequency and point in time of failure of repaired short external rotator muscles were determined in 27 total hip arthroplasties. The piriformis, triceps coxae, and obturator externus muscles were released close to the trochanter and reattached only if tension was low and if the tendon tissue allowed a good hold for anchoring the stitch. A radiopaque marker was attached to each side of the suture with maximum 1-cm distance between opposite markers. The distance between markers was determined on radiographs obtained 1 day and 3 months postoperatively; >/=2.5 cm indicated failure. Of 50 repaired short external rotator muscles, 35 (70%) failed-26 within the first day and 9 within 3 months postoperatively. In 2 hips, no failure of the repaired short external rotator muscles was observed. Repair of the short external rotator muscles after total hip arthroplasty contributes little to prevention of hip dislocation.

Failure of capsular enhanced short external rotator repair after total hip replacement.

The failure rate of repaired short external rotator muscles was determined in 20 total hip replacements done in 19 patients. The piriformis, both obturator and gemellus muscles, and the capsule were released close to the femur in a single flap leaving the tendon-capsule junction intact. After implantation of the prosthetic components, the flap was transosseously reattached with three grasping stitches, each encompassing the entire tendon-capsule junction. Radiopaque markers were attached to each side of the suture. The distance between markers was measured intraoperatively and then determined on radiographs 1 day and 3 months postoperatively; 25 mm or more and at least double the distance measured intraoperatively indicated failure. In 15 of the 20 hips the repair failed; in three hips the repaired flap was pulled out within the first day, and in 12, within 3 months. Capsular enhanced repairs of the short extensor rotator muscles, using the technique described, largely are unable to withstand forces that occur at the site of repair during the healing process. The quality of other repair techniques should be determined to identify superior techniques.

Fluoroscopically assisted stress radiography for varus-valgus stability assessment in flexion after total knee arthroplasty.

A radiographic technique to quantify varus and valgus joint laxity in flexion after total knee arthroplasty (TKA) was evaluated by means of inter-rater assessment in 12 patients. The test was shown to have good reliability. The simple method helps to detect instability in knee flexion that might be overlooked in a conventional clinical examination.