1 Department of Orthopaedic Surgery, Hospital del Trabajador, Ramon Carnicer 185, Providencia, Santiago, Chile.
2 Department of Orthopaedic Surgery, Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago, Chile
Traumatic anterior dislocation of the hip is an uncommon injury compared with posterior dislocation1. Nonoperative closed reduction is the treatment of choice for this injury. Recurrent anterior dislocation following such treatment is an exceptional event. We report the case of a patient with recurrent anterior hip dislocation that necessitated operative treatment. The patient was informed that information concerning this case would be submitted for publication.
Ahealthy thirty-five-year-old woman slipped and fell while mopping a wet floor, causing forced abduction of both lower extremities and external rotation of the right leg. She presented to the emergency room with severe pain in the right hip, which was fixed in abduction and external rotation. The neurovascular status of the extremity was normal. Radiographs revealed anterior hip dislocation without evidence of fracture or dysplasia (center-edge angle, 28°) (Fig. 1). The hip was reduced with closed manipulation within two hours after the injury, with the patient under general anesthesia. The patient was subsequently managed with bed rest without traction for one week. She then resumed normal walking and underwent a course of physical therapy.
Eight months later, while bearing full weight on the right lower extremity and rotating the trunk to the left, the patient sustained another anterior hip dislocation. Closed reduction was accomplished within four hours, and the patient was placed on bed rest for two weeks. Imaging studies, including conventional and false-profile hip radiographs, magnetic resonance images, and computerized tomographic arthrograms, showed only a redundancy of the anterior capsule and a normal equatorial edge angle2 of 22° (Fig. 2). There were no abnormalities of the labrum, femoral head, or acetabulum. Connective-tissue disorders were ruled out after a complete rheumatologic evaluation.
Two months after the second dislocation, the patient twisted while in bed and sustained a third dislocation. Operative repair was recommended. An anterolateral approach was used to expose the anterior capsule and the proximal part of the femur. The capsule was redundant but was not torn. It was imbricated with use of an inverted T overlapping capsulorrhaphy until maximal tension was achieved. Next, an intertrochanteric derotational osteotomy was performed just proximal to the lesser trochanter with 25° of external rotation of the distal fragment, and the site was fixed with a 95° dynamic condylar screw (Synthes, Oberdorf, Switzerland). Postoperative management consisted of partial weight-bearing for three months and progressive physiotherapy. Three months after surgery, range-of-motion testing revealed that the right hip had a 20° loss of internal rotation and a 15° increase of external rotation compared with the left hip. Union of the osteotomy site was observed at three months (Fig. 3). Two years after surgery, the dynamic condylar screw was removed to relieve local tenderness over the lateral aspect of the greater trochanter.
At the time of the five-year follow-up, the patient was pain-free and was still working in her pre-injury occupation as a janitor. At that time, the ranges of motion of the right and left hips were 125° and 140° of flexion, 20° and 45° of internal rotation, and 60° and 45° of external rotation, respectively. The patient had no further dislocation or subluxation of the right hip. The Harris hip score3 was 99 points. Radiographs showed no arthritic changes in the hip (Fig. 4).
Because of the inherent stability of the hip joint, traumatic anterior dislocation is uncommon. Thompson and Epstein reported that only 9% of hip dislocations occur anteriorly4. In our search of the literature, we only found seven reported cases of recurrent anterior hip dislocation in adults, including four in the English-language literature5-8.
It is important to identify any predisposing factors for recurrent dislocation, such as connective-tissue disorders, dysplasia of the femoral head or acetabular rim, fractures, neural deficits, or labral or capsular ruptures. Such factors may influence the likelihood of recurrent dislocation and its preferred treatment. Our patient had no predisposing factors for recurrent dislocation.
There is little information in the literature regarding the treatment of recurrent anterior hip dislocation, and all recommendations have been based on case reports with short durations of follow-up. Of the four cases reported in the English-language literature, one was treated nonoperatively with a hip-spica cast for eight weeks after a second dislocation5. Dall et al. described the use of a 45° external rotation femoral osteotomy combined with an iliopsoas transfer to the greater trochanter6. Shigenobu et al. reported on the use of a capsulorrhaphy and rotational acetabular osteotomy to treat acetabular dysplasia7.
We elected to externally rotate the femur only 25°, in contrast with the 45° described by Dall et al.6, in order to decrease the final rotational deformity. We then supplemented the osteotomy with a capsulorrhaphy to treat the computerized tomographic finding of a redundant capsule.
In this rare case, this combination of procedures was effective for avoiding both new dislocations and the development of arthritic changes in the hip at the time of the five-year follow-up. We could not determine whether the capsulorrhaphy or the rotational osteotomy was primarily responsible for the successful result.
The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at Hospital del Trabajador, Santiago, Chile
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