Upon questioning, she reported having had feelings of mild instability of the right hip during demanding activities (jogging, yoga) after sustaining a low-energy fall 1 month prior to her dislocation. On examination, she had significant apprehension about the right hip during gentle external rotation maneuvers. An MRA 2 weeks after the dislocation showed a large defect of the anterosuperior capsuloligamentous complex measuring 4 cm from medial to lateral and 2.5 cm superior to inferior (Figure 4). No loose bodies, chondral injuries, or recurrent tears of the labrum were seen. Typical postoperative changes were observed at the femoral head-neck junction.
Initially, we recommended nonoperative management with 6 weeks of toe-touch weight-bearing and strict avoidance of hip extension–external rotation maneuvers. No hip orthosis was used. After this period, the patient advanced to full weight-bearing and continued in hip-specific physical therapy. Despite continued therapy and avoidance of provocative maneuvers, the patient reported persistent feelings of right hip instability with significant apprehension during extension and external rotation of the right hip. A repeat MRA 4 months after the hip dislocation showed a persistent defect in the anterosuperior capsuloligamentous complex and no signs of avascular necrosis. After 6 months of conservative treatment, we recommended an open capsulorrhaphy of the right hip with autograft iliotibial band reconstruction of the iliofemoral ligament and capsule.
Six months after the dislocation, the patient underwent the recommended procedure. After induction of general anesthesia, she was placed in the supine position on a standard operating table. A Smith-Petersen approach was used to visualize the anterior hip structures. During deep dissection, we observed a large defect, measuring 2.5×4 cm (Figure 5A), in the anterior hip capsule, with only a thin pseudocapsule covering the femoral head. Extensive mobilization of the anterior capsule was unsuccessful.
The decision was made to harvest a graft from the patient’s ipsilateral iliotibial band. A skin incision was made over the iliotibial band in the distal midthigh region, and a 2.5×4-cm graft was harvested from the central portion of the iliotibial band. An arthrotomy was performed on the hip joint (Figure 5B). The labrum appeared healthy without recurrent tearing or fraying, and other than focal thinning on the superior acetabulum, the cartilage appeared healthy. A double-loaded anchor was placed in the supra-acetabular region, and the sutures were passed through the graft. Then, No. 2 nonabsorbable sutures were sequentially placed between the capsular remnant and the graft medially, inferiorly, and laterally. The graft was placed into position (Figure 5C) and the sutures were tied (Figure 5D).
Postoperatively, the patient was allowed toe-touch weight-bearing for 6 weeks, with strict avoidance of extension–external rotation maneuvers. She participated in a 12-week course of physical therapy with gradual advancement of activities. About a year after the capsulorrhaphy, she was able to resume all previous activities with only occasional low-level discomfort. She returned to the clinic 16 months after the capsulorrhaphy complaining of increased pain with long-distance running but denied feelings of instability. We performed an intra-articular hip injection under ultrasound guidance, which provided 100% relief of her symptoms. We obtained an MRA to evaluate for any recurrent capsular or labral injury (Figure 6). The previous anterosuperior capsular defect was not visible, and no signs of recurrent labral or cartilage injury were seen.
Discussion
With the increasing popularity of hip arthroscopy, more complications are being reported as well, including postoperative hip instability. Three separate cases of anterior hip instability have been published in the past several years.5-7
Ranawat and colleagues5 were the first to report a case of postoperative anterior hip dislocation after arthroscopy. Their patient was a 52-year-old woman with right hip pain and generalized ligamentous laxity. Her preoperative radiographs showed no evidence of degenerative changes, dysplasia, or femoroacetabular impingement. An MRA showed a peripheral tear of the anterosuperior labrum. At arthroscopy, her right hip was easily distracted 2 to 3 cm with what they described as “minimal traction.” A small 1- to 2-cm capsulotomy was performed about the anterior portal. A detached labral tear was identified and repaired with an anchor, and no rim resection was performed. To improve visualization of the peripheral compartment, they extended the previous capsulotomy 1 to 2 cm and débrided the edges. A cam-type lesion was identified and resected. Lastly, they performed an anterior capsular plication, specifically including the iliofemoral ligament. Postoperatively, the patient wore a hip orthosis for 6 weeks to prevent extension and external rotation of the hip as well as a foot brace at night for 3 weeks. The patient was allowed to partially bear weight for the first 6 weeks with use of crutches. Approximately 2 months postoperatively, she slipped and fell down a short flight of stairs. She was diagnosed with an anterior hip dislocation. After successful closed reduction, she was treated conservatively with the same regimen used earlier. She remained symptomatic over the next several months with signs of instability and apprehension, and she eventually underwent a repeat hip arthroscopy. A 1- to 2-cm tear of the anterior capsule and iliofemoral ligament was treated with a revision arthroscopic capsular plication. A postoperative regimen similar to that used at the index procedure was instituted and, at most recent follow-up, she was found to have occasional pain without instability.