Matsuda6 reported a case of acute iatrogenic hip dislocation after arthroscopic surgery. His patient was a 39-year-old woman with a mildly retroverted acetabulum leading to impingement about the hip. She had no signs of generalized ligamentous laxity. A hip arthroscopy in the lateral position was performed, with no comment about the extent of the capsulotomy. During the procedure, about 5 mm of anterosuperior acetabulum were removed as part of arthroscopic rim trimming for treatment of the pincer lesion. A femoral osteochondroplasty was also performed (unspecified size) to restore more normal anterolateral offset. One confounding factor was that supranormal hip distraction was needed for 20 minutes to aid in removal of a metallic piece from a radiofrequency ablator, which inadvertently detached. The patient experienced an anterior hip dislocation in the recovery room and was found to be unstable during closed reduction under general anesthesia. A mini-open capsular repair was performed, which showed a 1×1.5-cm defect in the anterolateral capsule. After closure of the defect, the hip was found to be stable under fluoroscopic examination. Postoperatively, the patient was allowed to perform partial weight-bearing in a hip-knee-ankle-foot orthosis for 2 months and then a flexible hip brace for 1 month. At 15-month follow-up, her hip was stable and she was pain-free.
Benali and Katthagen7 highlighted the significant contribution of the labrum to hip stability in a dysplastic hip. Their patient was a 49-year-old woman with mild hip dysplasia and a degenerative bucket-handle tear of the ventrolateral labrum. The patient underwent a near-complete labral resection and rim trimming at an outside institution. The patient began full weight-bearing at 3 weeks postoperatively and noticed considerable groin and back pain (no hip orthosis use was mentioned). After failed treatment for suspected lumbar pathology, she was referred to the authors’ clinic for further evaluation. Plain radiographs showed subluxation of the left hip with degenerative changes. The patient had an uneventful left total hip arthroplasty (THA).
After reviewing the 3 reported cases of hip instability after arthroscopy, we suggest that surgeons fully recognize and appreciate the delicate balance of stability and motion provided by the static and dynamic stabilizers of the hip joint, and be cognizant of potential imbalance created by surgical intervention.8,9 Postarthroscopic hip instability appears to be multifactorial in nature, because all of the reported cases detailed different factors, both patient- and surgeon-related, contributing to instability.
Ranawat and colleagues5 identified several factors that may have contributed to the anterior hip dislocation sustained by their patient, including the patient’s generalized ligamentous laxity, performance of a capsulectomy (with repair of iliofemoral ligament), and a traumatic fall. Benali and Katthagen7 (although they did not perform the index procedure) described the disastrous complication of overzealous labral resection and rim trimming in a patient with hip dysplasia. Matsuda6 performed a labral resection and rim trimming, an extended (unspecified size) capsulotomy, and also used supranormal traction for 20 minutes to remove an iatrogenic foreign body. Surgeons performing hip arthroscopies should be aware of all these factors, because many are directly controlled by the surgeon.
The only factor we feel may have contributed to hip instability in our patient was the performance of a capsulotomy without closure. Our patient was an otherwise healthy woman with no signs of ligamentous laxity, hip dysplasia, or retroversion of the acetabulum. We did not perform a labral resection or rim trimming. We use modified anterior and anterolateral portals, and electrocautery to connect the portals. This typically leads to a release of a thin strip (less than 5 mm wide) of 3 cm of capsule. Based upon findings at rare second-look arthroscopy for recurrent symptoms, Dr. Guanche has observed that the capsulotomy from the initial procedure heals with normal-appearing tissue. Also, during peripheral compartment arthroscopy, we do not routinely release the iliofemoral ligament, and the orbicular ligament is left intact. Instead, we prefer to flex the hip and débride only enough capsular tissue to allow for adequate visualization.
Little has been published on capsulotomy closure after hip arthroscopy, and no consensus exists. Our standard practice is to not close the capsulotomy, which accords with the practice of other surgeons.9 There is concern, however, that extensive capsulotomy leading to injury or disruption of the iliofemoral ligament may cause anterior hip instability, driving other prominent hip arthroscopists to routinely close the capsulotomy.9,10 Myers and colleagues10 published a recent biomechanical study on the role of the labrum and the capsular ligaments in hip stability. They concluded that the iliofemoral ligament plays a significant role in limiting external rotation and anterior translation of the femoral head, and recommended closure of the capsulotomy after arthroscopy. Of note, Dr. Guanche has performed more than 1500 hip arthroscopic procedures in the past 5 years, and we are aware of only 2 patients who have sustained anterior hip dislocations, in spite of our not closing the capsulotomy defect. This highlights an important clinical question in need of further investigation.