A fifty-one-year-old man presented with a three-year history of insidious-onset, increasingly intense anterior right groin pain, exacerbated by standing from a seated position or by playing golf. The patient had completed a trial of nonsteroidal anti-inflammatory medications and physical therapy without relief of symptoms. An intra-articular injection of corticosteroids provided excellent but transient relief of symptoms. His medical and surgical history was unremarkable, and he took no medications.
On examination, the patient appeared well with no deformity of the spine or lower extremities. He walked with an antalgic gait but without a Trendelenburg lurch. He had mild tenderness to deep palpitation in the right groin and over the adductor tendons. Motion of the right hip, which was symmetric with that of the asymptomatic left hip, included 120° of flexion, 15° of internal rotation with the hip flexed 90°, 45° of external rotation with the hip flexed 90°, and 45° of abduction. The result of strength testing was 5 of 5 for the hip flexors, abductors, and adductors. Impingement testing was clearly positive with substantial groin pain on the right side. The Harris hip score4 was 56.1 points, the Hip Outcome Score5 (activities of daily living) was 47.1 points, and the Hip Outcome Score (sports) was 22.2 points.
Radiographs revealed focal acetabular retroversion anterosuperiorly (including the crossover sign and the ischial spine sign) and loss of neck offset secondary to an anterolateral cam lesion on the extended neck lateral hip view (Figs. 1-A and 1-B). The alpha angle on the preoperative Dunn lateral radiograph measured 46°, and an impingement trough was present. The alpha angle was within normal limits, but the anterolateral location and relatively distal location of the major cam lesion in this case limited the value of this numeric alpha angle because the Dunn lateral radiographic view best delineates the (proximal) anterosuperior aspects of the femoral head-and-neck junction. The Tönnis angle was 8°, and the lateral center-edge angle was 26°; both were within normal limits6. There was no evidence of osteonecrosis, and the joint spaces were well preserved. A triple-phase bone scan was negative for any active inflammatory process and/or potential stress fracture. Magnetic resonance imaging (MRI) showed chondromalacia of the acetabulum anterosuperiorly (1.4 × 1.3 cm) and an anterosuperior labral tear consistent with impingement (Figs. 2-A and 2-B). In light of the symptoms, the radiographic findings, and the response to the corticosteroid injection, the risks and benefits of arthroscopic hip surgery to address the impingement and resulting labral damage were reviewed and the patient elected to proceed with the surgery.
Fig. 1-A Preoperative anteroposterior radiograph of the pelvis showing focal acetabular overcoverage (thick arrow), crossover of the anterior wall (dashed arrow), and the ischial spine sign (thin arrow). Fig. 1-B Preoperative lateral radiograph of the hip showing an impingement trough (arrow) and loss of femoral neck offset.
Fig. 2-A Axial cut MRI of the hip showing the alpha angle. Fig. 2-B Axial cut MRI showing the labral degeneration/tear (arrow).
The patient was positioned supine in traction on the fracture table. After adequate distraction of the hip joint, arthroscopy of the central compartment was performed with use of standard anterolateral and modified anterior portals created under fluoroscopic guidance. Diagnostic arthroscopy revealed an anterosuperior labral tear and full-thickness chondral delamination adjacent to the labral tear. There was also synovitis and an associated posterior contre-coup labral injury consistent with damage from the impingement lesions (Figs. 3-A and 3-B). An interportal capsulotomy was performed to improve visualization, and a thorough synovectomy was performed. The labral tear was debrided and smoothly contoured with preservation of functional labral tissue circumferentially around the acetabulum. The focal pincer lesion was decompressed anterosuperiorly with an arthroscopic burr from the extra-articular side of the labrum. The chondrolabral junction was left undisturbed, and the labrum remained attached while the osseous prominence was addressed from an extra-articular position. Intraoperative fluoroscopy confirmed an adequate osseous resection, and there was sufficient labral tissue to provide a joint suction seal effect. The traction was subsequently released, and the hip was flexed to allow visualization of the peripheral compartment. A T-capsulotomy was performed over the anterosuperior aspect of the neck with a Beaver blade and revealed the underlying loss of femoral offset and the cam lesion from the 12 o'clock to the 4 o'clock position, which corresponds to the anterolateral aspect of the head-neck junction. Grooving and herniation pits from impaction of the cam and pincer lesions were visible. The margins of the cam lesion were carefully outlined as far lateral as the superior retinacular vessels and distally to the normal cortical neck. The cam lesion was resected with use of an arthroscopic burr to restore normal offset, which was confirmed fluoroscopically on the extended neck lateral view (Figs. 4-A and 4-B). Care was taken to create a gradual contour at the head-neck junction and to avoid an overzealous resection (Fig. 5). Dynamic hip flexion and internal rotation revealed excellent hip clearance under direct arthroscopic visualization. An approximate increase of 10° of internal rotation was noted with the hip flexed to 90°, and external rotation did not change in this position.
Fig. 3-A Arthroscopic view of the labral tear. Fig. 3-B Arthroscopic view of the chondral wear.
Fig. 4-A Preoperative lateral fluoroscopic view before decompression to treat the cam impingement. Fig. 4-B Postoperative lateral fluoroscopic view following decompression to treat the cam impingement.
Arthroscopic view following decompression to treat the cam impingement.
There were no complications during the initial postoperative course as the patient complied with our routine protocol of wearing a protective hip orthosis, continuous passive motion from 30° to 70° three times daily, and partial weight-bearing of 20 lb (9 kg) with the foot flat and with crutch assistance. The anterior hip pain was reduced, and the patient was walking with less discomfort. However, three weeks after surgery, he walked for up to three miles (4.8 km) a day for exercise against recommendations. He also attended supervised physical therapy sessions three times a week that emphasized gentle, passive range-of-motion exercises. Five weeks after surgery, he developed new-onset groin pain following an unremarkable session of physical therapy. He was able to walk, but the anterior hip pain was different from what he had experienced preoperatively. He did not recall any trauma, strenuous activity, or associated systemic symptoms. Examination revealed painless hip rotation but pain with axial loading through the hip joint and with weight-bearing. Radiographs were obtained immediately, and they revealed a nondisplaced basicervical femoral neck fracture (Fig. 6). The patient was informed of the finding, and an urgent consultation with an orthopaedic trauma surgeon was obtained. To avoid the potential complication of displacement of a femoral neck fracture, surgery was performed with capsulotomy to assess anatomic reduction and fixation with use of a low-profile proximal femoral locking plate and screws.
Anteroposterior radiograph showing the undisplaced subcapital fracture of the right hip. The arrows show the fracture line.
The patient had an uneventful postoperative course, and the fracture healed without complications. Hip motion was pain-free and included 120° of flexion, 45° of external rotation, and 25° of internal rotation. There were no implant-related complications, and twelve months postoperatively radiographs confirmed a healed fracture (Figs. 7-A and 7-B). One and a half years following the fracture treatment, the Harris hip score was 83.6 points, the Hip Outcome Score (activities of daily living) was 92.7 points, the Hip Outcome Score (sports) was 58.3 points.
Anteroposterior (Fig. 7-A) and frog-leg lateral (Fig. 7-B) hip radiographs made one year after fixation of the hip fracture.
Investigations to identify a possible occult risk or predisposition to fracture, including a dual x-ray absorptiometry scan and metabolic bone laboratory screening, revealed normal findings.