A fifty-two-year-old Caucasian woman presented to our clinic in the fall of 2005 with a two-year history of pain in the right groin and anterior part of the thigh and a sensation of "popping" in the right hip. She had undergone bilateral shoulder capsulorrhaphy for multidirectional instability (the right shoulder in 2002, and the left in 2000) as well as bilateral knee meniscal repairs (both in 1999). On physical examination, both the affected right hip and the asymptomatic left hip had flexion to 120° and hyperextension to 15° to 20° in each hip. In 90° of flexion, each hip had 60° of external rotation and 40° of internal rotation. During range-of-motion testing, the patient had right groin pain with flexion and internal rotation of the hip as well as apprehension when the hip was placed in a position of extension, abduction, and external rotation14. With axial traction, the right hip was easily distracted approximately 1 to 2 cm and with no appreciable firm end point.
In full extension, the right hip had approximately 60° of external rotation and 30° of internal rotation, whereas the left hip had only 50° of external rotation and 30° of internal rotation. In flexion, abduction, and external rotation (FABER test15), each knee could be pressed downward such that there was a distance of <3 cm between the lateral aspect of the knee and the examination table. The patient had normal results bilaterally on the Ober test15 (for iliotibial band tightness) and no tenderness about either greater trochanter.
The patient also had ligamentous laxity of other joints, demonstrated by hyperextension of the interphalangeal, first carpometacarpal, elbow, and knee joints. We also noted hyperelasticity of the skin on examination. She had never had a genetic workup for a collagen disorder, but it is notable that results were normal on echocardiograms that had been performed previously to rule out aortic abnormalities associated with collagen disorders. The results of motor, sensory, and vascular examination were normal.
The imaging examination included plain radiographs and a magnetic resonance arthrogram of the right hip. The plain radiographs showed no evidence of degenerative changes, developmental dysplasia of the hip, or femoroacetabular impingement (Figs. 1-A and 1-B). The magnetic resonance arthrogram showed a peripheral tear of the anterosuperior portion of the right labrum (Fig. 1-C). An intra-articular injection to the hip was then performed, consisting of 80 mg of triamcinolone and 6 mL each of 1% Xylocaine (lidocaine) and 0.25% bupivacaine. This injection immediately relieved all of the patient's symptoms, and she remained asymptomatic for six weeks. During that time, she performed a hip-specific physical therapy protocol consisting of use of a stationary bicycle, passive range of motion, isometric strengthening, abdominal and low-back strengthening, proprioceptive training, and cryotherapy16. However, after six weeks, the hip became symptomatic again.
Due to the persistent symptoms, the response to injection, and the arthrographic findings of a labral tear, we recommended arthroscopic treatment of the labral tear and capsular laxity. In the fall of 2006, an arthroscopic procedure was performed. The patient was given general anesthesia and was placed in the supine position on a fracture table. The hip was easily distracted approximately 2 to 3 cm with minimal traction. Through standard anterior and anterolateral portals that were directed under fluoroscopy, a detached peripheral labral tear was identified in the central compartment. A small (1 to 2 cm) capsulotomy was performed at the anterior portal for enhanced exposure and maneuverability. The labrum was repaired with number-2 FiberWire sutures from one 3-mm Bio-SutureTak anchor (Arthrex, Naples, Florida). No acetabular rim resection was performed. Traction was then released, and the peripheral compartment was entered.
The capsulotomy was extended an additional 1 to 2 cm and the edges of the capsule were débrided, resulting in a partial capsulectomy that improved visualization and maneuverability in the peripheral compartment. Although not suspected from an examination of the original radiographs, a cam-type impingement lesion was identified intraoperatively at the anterior portion of the femoral head-neck junction17. We performed a femoral osteochondroplasty to protect the labral repair and alleviate any secondary impingement from the ligamentous laxity18. The hip joint was then taken through a full range of motion in all planes without any evidence of impingement. Traction was then reapplied and the arthroscope was returned to the central compartment, where a capsular plication was performed with two free FiberWire sutures to close the anterior capsule and, specifically, the iliofemoral ligament (see Appendix).
The patient wore a hip orthosis (Philippon K.A.F. Positioning Kit; Bledsoe Brace Systems, Grand Prairie, Texas) for six weeks to prevent hyperextension and external rotation during gait; in addition, to protect the anterior repair, the patient wore a foot brace for three weeks at night to restrict external rotation11. We recommended only 20 lb (9 kg) of protected flat-foot weight-bearing with the aid of crutches for five weeks. At the six-week follow-up visit, the patient was progressing well and was advised to discontinue the brace and begin full weight-bearing.
Approximately two months postoperatively, while on vacation, the patient slipped while walking down a short flight of stairs and fell with the affected extremity in a position of extension. She had immediate right groin pain and an inability to bear weight. She was taken to a local emergency room and diagnosed with anterior dislocation of the hip with no associated fractures. She promptly underwent closed reduction without difficulty. The reduction was deemed concentric, and she was referred back to our care after being placed on crutches. Ten days after the dislocation, she presented to our clinic with hip pain and apprehension with regard to the anterior portion of the hip. A repeat magnetic resonance arthrogram was performed approximately three weeks after the dislocation occurred, and the arthrogram was interpreted as showing a full-thickness tear (approximately 1 to 2 cm in length) of the iliofemoral ligament but no evidence of loose bodies or chondral injuries (Fig. 2).
We recommended continued nonoperative management over the next few months. The patient was advised to continue crutch therapy with 20 lb (9 kg) of flat-foot weight-bearing for six weeks, resume use of the brace to avoid hyperextension and external rotation, and continue physical therapy to maintain hip motion within the set parameters. After ten weeks of physical therapy, she had no substantial improvement. Her discomfort was still present, and it intensified when she removed the brace or walked without the aid of crutches. She experienced substantial pain with flexion and internal rotation. She also had apprehension with abduction and external rotation. In light of her failure to make progress on a nonoperative regimen, she chose to undergo a revision hip arthroscopy and capsular plication.
During the revision arthroscopy, the patient was again placed in traction while under general anesthesia. Standard anterolateral and anterior portals were made with the aid of fluoroscopy. On inspection, there was an approximately 1 to 2-cm tear of the anterior capsule and iliofemoral ligament in the region of the prior capsulectomy. The labrum was edematous, erythematous, and partially frayed but still intact, specifically at the peripheral labral attachment site (Fig. 3). A capsular plication was again performed in the central compartment and augmented by a peripheral compartment plication out of traction. Details of the technique are presented in the Appendix. Postoperatively, the patient was then placed into a knee-ankle-foot orthosis (Bledsoe Brace Systems) to limit extension and external rotation for eight weeks. At the time of the six-month follow-up, the patient reported resolution of her apprehension but had occasional pain; radiographs revealed no evidence of osteonecrosis.
H ip dislocations account for only about 5% of all joint dislocations, and only 10% of these are anterior dislocations19-21. Anterior dislocations are generally caused by a high-energy traumatic force being applied to the posterior aspect of the proximal part of the femur. Biomechanical analyses of the iliofemoral ligament, ischiofemoral ligament, and femoral arcuate ligaments have resulted in the conclusion that the iliofemoral ligament is the strongest of the three in the ability to withstand the highest amount of force before failure22,23; however, it was also found to be the most susceptible to minor degrees of strain, requiring only small displacements to fail. The iliofemoral ligament, which originates on the anterior superior iliac spine and terminates along the intertrochanteric line, is a condensation of anterior capsular fibers and acts to restrain excessive extension, external rotation, and forward displacement. Anterior dislocations of the hip are commonly due to failures of the iliofemoral ligament.
Our patient was at an increased risk for a hip dislocation because of multiple factors, including ligamentous laxity, a previous capsulectomy and repair of the iliofemoral ligament, and a traumatic fall. Although ligamentous laxity and trauma are recognized risk factors for hip instability2, a capsulectomy, which was performed to gain improved arthroscopic visualization in the peripheral compartment, has not been described previously as a risk factor. Although the capsulectomy was repaired at the end of the first surgical procedure, the repair was either not fully healed or was inadequate to restrain the anterior forces during the fall and thus prevent her hip dislocation. It is notable that the patient experienced minimal symptoms before the fall, possibly indicating that the initial plication was strong enough to withstand the smaller forces experienced during activities of daily living.
This case report highlights numerous issues. It brings attention to potential consequences of violating the iliofemoral ligament during peripheral compartment arthroscopy of the hip. Although there are techniques to enter the peripheral compartment without violating the anterior capsule of the hip, anterior capsulectomy is routinely performed in hip arthroscopy. In addition, most arthroscopists who perform capsulectomies to gain increased exposure and visualization do not repair the anterior capsular defect. As of the time of writing, we are not aware of any previous reports documenting any deleterious effects of partial anterior capsulectomies.
We believe this case report also illustrates how capsular laxity may be a causative factor for labral tears2. On the basis of the operative diagnostic studies, we did not believe this patient had classic femoroacetabular impingement17,24; intraoperatively, however, we found it necessary to perform an osteoplasty to protect the labral repair because we noted abutment by the femoral neck on the acetabulum and labrum due to the large range of motion conferred by capsular laxity. This scenario may be analogous to the secondary impingement syndrome that may occur in the shoulder25-27.
Finally, this case report also highlights the emerging arthroscopic techniques that are being used during capsular plication. Plications can be performed in either the central or the peripheral compartment, with each technique having advantages and disadvantages. The central technique is preferred because a capsulectomy is not required; however, because this technique is performed under traction, the tissue is under tension and the degree of plication is limited. The peripheral technique may or may not require a capsulectomy, and it allows for a larger plication because the hip is not under traction and can be flexed. Similar to what has been found with arthroscopic techniques of the shoulder, there are limits to arthroscopic techniques in the hip, and open procedures may be necessary28.
We are now reluctant to perform a capsulectomy in patients with capsular laxity. If one is necessary, we repair the defect in the peripheral compartment while keeping the hip in a flexed position, which we believe provides a stouter repair. In addition, our postoperative rehabilitation protocol is more conservative, with protected weight-bearing and bracing for as much as eight weeks and with avoidance of extension and external rotation16,23. We now have a low threshold for making a false-profile radiograph of the hip to assess mild forms of acetabular dysplasia, and we obtain computed tomographic scans to accurately assess both femoral and acetabular version, which are both risk factors for anterior instability. Finally, when we perform an arthroscopic osteoplasty, we make the smallest possible capsulectomy that still provides adequate visualization of the proximal part of the femur.
As the number of hip arthroscopic procedures continues to increase, orthopaedic surgeons need a heightened awareness of the unique concerns and complications that may be associated with these procedures, including the consequences of an iliofemoral capsulectomy and the possibility of subsequent dislocation.