Drs Lim (Byung-Ho), Jang, Park, and Lim (Seung-Jae) are from the Department of Orthopedic Surgery, Samsung Medical Center,
Sungkyunkwan University School of Medicine, Seoul, South Korea.
Drs Lim (Byung-Ho), Jang, Park, and Lim (Seung-Jae) have no relevant financial relationships to disclose.
Correspondence should be addressed to: Seung-Jae Lim, MD, Department of Orthopedic Surgery, Samsung Medical Center, 50 Ilwon-Dong,
Kangnam-Ku, Seoul 135-710, South Korea (limsj@skku.edu).
Obturator (anterior-inferior) dislocation of the hip is rare, and represents only 7% of all traumatic hip dislocations.
1,2
This type of hip dislocation is associated with forced abduction, external rotation, and flexion of the hip, whereby the
femoral head extrudes through the anterior capsule beneath the pubofemoral ligament and comes to rest anterior to the obturator
ring. Frequently, this also causes an impacted fracture on the anterosuperior aspect of the femoral head,
3–5
which is usually treated nonoperatively or by simple removal of small osteochondral fragments. However, obturator hip dislocation
associated with a large femoral head fracture is extremely rare, and to our knowledge, only 1 previous case has been reported.
6
In this case, the patient had no damage to articular cartilage and was simply treated by open reduction and internal fixation
of the fractured fragment with malleolar screws.
This article describes a case of a young adult with obturator fracture-dislocation of the hip, involving a large femoral head
fragment and severe delamination of articular cartilage.
Case Report
A 16-year-old boy, who had undergone unsuccessful closed reduction at another institution 6 hours previously, presented to
our emergency room after a motorcycle accident. The patient reported left hip pain and an inability to straighten his left
thigh. Blood pressure and vital signs were essentially normal, as were systemic examination findings. Physical examination
demonstrated that his left hip was in flexion, abduction, and external rotation. Limb sensation was intact, dorsalis pedis
pulse was normal, and he was able to actively flex and extend his left foot. Anteroposterior radiography and computed tomography
(CT) of the pelvis revealed an obturator dislocation of the hip with a large fracture fragment, originating from the femoral
head, attached in the acetabulum (Figure ).
Emergent surgery was performed 6 hours after presentation using an anterolateral approach
7
in the lateral decubitus position (Figure ). This approach allowed access to the structures impeding reduction, including the rectus femoris and iliopsoas muscles,
and torn joint capsules. After releasing these interposing tissues, the hip was able to be reduced. The hip was then redislocated
anteriorly through the operative window to scrutinize the femoral head and fix the femoral head fragment (Figure ). The articular cartilage of the femoral head was found to be severely delaminated and to have peeled away from the head
in some areas (Figures ). The large anterosuperior femoral head fragment, held in the ligamentum teres of the acetabulum, was released and fixed
under direct vision to the dislocated femoral head with countersunk Acutrak screws (Acumed Inc, Beaverton, Oregon) (Figure
). Delaminated and detached articular cartilage were then reattached to underlying subchondral bone using suture anchors (Mini-Revo;
Linvatec Inc, Largo, Florida) and multiple absorbable sutures (Vicryl Plus; Ethicon Inc, Somerville, New Jersey) (Figure ).
The patient was kept nonweight bearing for 6 weeks postoperatively and was allowed to resume full weight bearing gradually.
He returned to normal activities of daily living at 14 weeks. No wound-healing disturbance, infection, or nerve lesion occurred.
At 9 months postoperatively, arthroscopic examination showed complete healing of the fracture and cartilage lesions (Figure
), and at 12-month follow-up, no clinical or radiographic evidence of arthritis or osteonecrosis was evident (Figure ). He had no pain or limp, and achieved an excellent result according to Epstein’s clinical evaluation criteria.
1
Discussion
Obturator hip dislocation is a rare injury that usually results from high-energy trauma in young adults. Impacted fractures
of the femoral head have been reported in 35% to 55% of patients after anterior dislocation.
3–5
Few cases of complete or indentation femoral neck fracture after anterior hip dislocation have been reported in the literature.
8–10
However, obturator hip dislocation associated with a large femoral head fracture is extremely rare,
6
and to our knowledge, no obturator hip dislocation associated with a large femoral head fragment and severe delamination
of articular cartilage has previously been described.
Many aspects of the treatment of femoral head fractures associated with traumatic anterior hip dislocation are disagreed upon.
Epstein and Wiss
1
recommended that all traumatic anterior dislocations of the hip must be treated as surgical emergencies, and that multiple
attempts at closed reduction be avoided because of the danger of developing avascular necrosis of the femoral head or fracture
of the femoral neck. Furthermore, the anatomical reduction of anterior hip dislocation associated with a displaced femoral
head or neck fracture is difficult by closed reduction.
Various surgical approaches have been advocated for open reduction of an irreducible anterior fracture-dislocation of the
hip, although the anterior approach has commonly been used in this situation.
1,6,11
Recently, a trochanteric flip osteotomy, as described by Ganz et al,
12
was also used to treat anterior fracture-dislocation of the hip.
10,13
In the present case, an anterolateral approach
7
was used in the lateral decubitus position, as this provided direct access to the structures impeding reduction, which included
the rectus femoris and iliopsoas muscles and torn joint capsules. This approach also allowed the hip to be easily redislocated
anteriorly through the operation window, which allowed the femoral head to be scrutinized and fracture fixation and cartilage
repair to be performed. In addition, we prefer to perform this procedure without osteotomy, because of the risk of complications
related to trochanteric fixation, such as breakage of fixation devices, bursitis, or union failure.
14
Prosthetic replacement is an excellent treatment option for older patients with irreducible fracture-dislocation of the hip
and for patients with neglected obturator hip dislocation,
15
but it is not ideal for younger patients. Impacted femoral head fractures associated with obturator hip dislocation are usually
treated nonoperatively or by removal of small osteochondral fragments. However, a large fracture fragment cephalad to the
fovea must be fixed rigidly, because this area is in contact with the articular cartilage of the acetabulum and is involved
in weight bearing.
Richards and Howe
6
first reported open reduction and internal fixation of a displaced femoral head fragment associated with obturator fracture-dislocation
of the hip. In their case, the patient had no damage to the articular cartilage of the femoral head, and the fractured fragment
was fixed with 2 malleolar screws. However, in the present case, irreducible obturator dislocation of the hip was associated
with a large femoral head fragment and severe delamination of articular cartilage. After open reduction of the hip joint using
an anterolateral approach, the large femoral head fragment was completely released from the ligamentum teres and fixed to
the dislocated femoral head with headless screws, and severely delaminated cartilages were repaired with suture anchors and
absorbable sutures. This approach was chosen because we believe that internal fixation of femoral head fractures should achieve
rigid fixation, preferably with compression between the fracture fragment and the remainder of the femoral head. Today, numerous
implants, such as countersunk lag screws, headless screws, and bioabsorbable pins, are available for the treatment of femoral
head fractures.
16
We believe that all injured cartilages, including smaller fragments, must be fixed because hip articular cartilage does not
regenerate in adults. Furthermore, articular cartilage defects of the femoral head are often associated with worsening symptoms
and early degenerative osteoarthritis.
17
The reconstruction of injured cartilage is of greater importance in young patients. In the present case, arthroscopic follow-up
examination at 9 months postoperatively demonstrated complete healing of the fracture and cartilage lesions, and at the subsequent
12-month follow-up, there was no clinical or radiographic evidence of arthritis or osteonecrosis. To our knowledge, no previous
report exists on arthroscopic follow-up of a repaired femoral head cartilage in patient with an anterior fracture-dislocation
of the hip.
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