Abstract
TOH was first described by Curtis and Kinkade in 1959, in women in the 3rd trimester of pregnancy. Later the disease was described in middle-aged males (4th-6th decade). Very rare occurrence was described in children and in females not connected to pregnancy.
Thirty-six patients with sudden hip pain with normal radiographs but increase uptake on bone scan and bone marrow edema in the head and neck on MRI were investigated by the senior author. Two patients (age 16 and 18) had Osteoid osteoma in the neck and two elderly patients (72 female and 75 male) had stress fracture in the neck were excluded from the study. The rest, 32 patients (28 males and 4 females – not connected to pregnancy) are the study group. Three male patients had bilateral involvement 1 to 3 years apart. The initial symptoms were pain, limping with minimal or no restriction in range of motion. All patients had plain radiographs, bone scan and MRI. Bone scan was positive in all and MRI showed bone edema in the neck and head in all. All patients were initially treated by non-weight bearing for six weeks followed by additional MRI every 6 weeks till the bone edema and symptoms subsided. In all patients the third MRI showed improvement in bone edema and were allowed to weight bear. None of the patients showed progression from TOH to AVN even in 7 patients with Crescent lines on T-1 images.
The mean F.U. was 51 months (4 to 131 months). Five patients still complained of mild pain in the affected hip, all with the exception of one had full range of motion. None of the patients had limping. All the plain radiographs were normal, with no signs of AVN or deformity of the head. In contrast the Dexa measurements of all patients showed decreased bone density in the affected hip compared to the other.
Conclusion: TOH is a benign disease. Even when Crescent lines are present all patients heal successfully without signs of AVN. Excellent correlation was found between subsidence of pain and improvement of bone edema on MRI. AVN and TOH are two distinct entities and therefore the treatment of TOH should always be conservative.
The abstracts were prepared by Ms Orah Naor. Correspondence should be addressed to Israel Orthopaedic Association at PO Box 7845, Haifa 31074, Israel.
