Background: Primary synovial osteochondromatosis of the hip, a rare
benign condition characterized by multiple intra-articular osteochondral loose
bodies and synovial hyperplasia, may result in mechanical symptoms and
degenerative arthritis if untreated. The purpose of this study was to report
the results of arthrotomy alone or combined with anterior dislocation of the
hip to perform synovectomy and removal of loose bodies in patients with this
Methods: We retrospectively reviewed a consecutive series of
twenty-one patients (twenty-one hips) with primary synovial
osteochondromatosis of the hip treated with open surgical débridement.
On the basis of the extent of extra-articular involvement as seen on
preoperative magnetic resonance imaging, eight of the twenty-one patients
underwent synovectomy and removal of loose bodies following anterior
dislocation of the hip and thirteen underwent the same procedure with
arthrotomy alone. At a mean of 4.4 years postoperatively, the patients were
assessed clinically and radiographically with special attention to disease
recurrence, osteoarthritis progression, and surgical complications.
Results: The mean Harris hip score for the entire series of patients
improved from 58 points preoperatively to 91 points at the time of the latest
follow-up. Eighteen of the twenty-one patients had a good or excellent
clinical result, and seventeen patients were satisfied with the result of the
surgery. The clinical scores, patient satisfaction scores, and radiographic
grades of osteoarthritis at the time of the latest follow-up did not differ
significantly between the group treated with dislocation and the group treated
without dislocation. Symptomatic disease recurred in two of the thirteen hips
treated with arthrotomy alone and in none of the hips that had undergone
dislocation. However, the surgical complication rate was higher in the group
treated with dislocation than it was in the group treated without dislocation
(p = 0.042). While patients with some signs of mild osteoarthritis at the
initial procedure had a higher rate of osteoarthritis progression, severe
osteoarthritis requiring arthroplasty had developed in only one patient at the
time of follow-up.
Conclusions: At a mean of 4.4 years postoperatively, we found that
open synovectomy and removal of loose bodies for the treatment of primary
synovial osteochondromatosis of the hip is a reliable procedure that can
effectively relieve symptoms. Our results also indicated that synovial
osteochondromatosis may recur in patients with extensive involvement who are
treated with synovectomy alone without dislocation of the hip; however,
surgical complications are more likely to occur in patients managed with
anterior dislocation of the hip and synovectomy.
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.