Rupture of the ilio-psoas tendon after a total hip arthroplasty: an unusual cause of radio-lucency of the lesser trochanter simulating a malignancy.

Avulsion fracture or progressive radiolucency of lesser trochanter is considered a pathognomic finding in patients with malignancies. Although surgical release of the iliopsoas tendon may be required during a total hip arthroplasty (THA), there is no literature on spontaneous rupture of the ilio-psoas tendon after a THA causing significant functional impairment. We report here such a case, which developed progressive radiolucency of the lesser trochanter over six years after a THA, simulating a malignancy. The diagnosis was confirmed by MRI. Because of the chronic nature of the lesion, gross retraction of the tendon into the pelvis, and low demand of our patient, he was treated by physiotherapy and gait training. Injury to the ilio-psoas tendon can occur in various steps of the THA and extreme care should be taken to avoid this injury. Prevention during surgery is better, although there are no reports of repair in the THA setting. This condition should be considered in patients who present with progressive radioluceny of the lesser trochanter, especially in the setting of a hip/pelvic surgery. Awareness and earlier recognition of the signs and symptoms of this condition will aid in diagnosis and will direct appropriate management.