Abstract
Background
In total hip arthroplasty (THA), the importance of preserving muscle is widely recognized. It is important to preserve the short external rotator muscles because they contribute to joint stability and prevent postoperative dislocation. However, despite careful capsular release and femoral rasping, damage to the short external rotator muscles may occur. The Optymis Shot Stem preserves more bone and surrounding tissue than does a traditional primary stem. We investigated the usefulness of the stem in terms of the extent of preservation of the tendon attachment on the greater trochanter.
Method
In this study, we enrolled 31 consecutive patients (39 hips; 6 males, 25 females) who underwent THA. Simultaneous bilateral THA was performed in 8 patients. The patients’ mean age was 56.1 years. Diagnoses included developmental dysplasia in 35 hips (Crowe group 1: 31 hips, group 2: 4 hips), and sequel of Perthes disease in 4 hips. All THAs were performed via the direct anterior approach without traction tables. The femoral procedure was performed with the hip hyperextended, and posterior capsular release was performed if the femoral procedure became technically difficult. We compared the following among patients: the operative time, intraoperative blood loss, length of hospital stay, rate of posterior capsular release, postoperative radiographic findings, WOMAC score before and after surgery, and any complications.
Results
The mean operative time was 42.0 ± 8.9 min, the mean intraoperative blood loss was 308 ± 196 g, and the mean hospital stay was 6.7 ± 1.3 days. Posterior capsular release was performed in 17 hips [44%; 10 hips (32%) in Crowe group 1, 8 hips (88%) for other diagnoses]. The total WOMAC score improved significantly from 42.4 points preoperatively to 11.2 points at 3 months preoperatively. A postoperative stem subsidence ≥3 mm was observed in 1 hip (2.6%), whereas postoperative dislocation, intra- and postoperative periprosthetic fracture, and thigh pain were not observed.
Conclusions
The Optymis Short Stem could be placed without performing posterior capsular release in 68% of patients with Crowe group 1 developmental dysplasia. We therefore consider the stem as useful for preserving the tendon attachment on the greater trochanter.
