Impact of Recurrent, Self-Reducible Prosthetic Hip Dislocation on Rehabilitation Course After Contralateral Total Knee Arthroplasty: A Case Report

Case Diagnosis: 73 year-old male with history of bilateral total hip arthroplasties (THA) whose course in acute inpatient rehabilitation (AIR) after left total knee arthroplasty (TKA) was complicated by worsening intermittent discomfort and instability of the right hip.

Case Description or Program Description: The patient underwent left TKA and reported a 3-month history of intermittent, non-painful sensations described as “dislocation” of right prosthetic hip. The patient endorsed needing to “pop it back in” with movements of the leg in order to relieve the discomfort and be able to bear weight. Initial X-rays demonstrated no dislocation, and he was cleared for full weightbearing of right leg and transferred to AIR. He made progress in rehabilitation but an increasing frequency of hip symptoms hindered discharge. Repeat X-ray and CT pelvis imaging later revealed right femoral head subluxation and dislocation, respectively.

Setting: Acute Inpatient Rehabilitation Unit

Assessment/Results: Orthopedics re-evaluated and recommended protected weightbearing as tolerated with walker, posterior hip precautions, and use of abduction brace and pillow. The patient had some initial reduction in frequency of symptoms with several adjustments of the orthosis needed. He was discharged home to continue outpatient therapy but continued to suffer frequent dislocations. A hip abduction bar with pressure relief ankle foot orthosis was trialed but not tolerated. Ultimately, he completed rehabilitation of left knee and awaits medical clearance for revision of right THA.

Discussion (relevance): This case highlights prosthetic hip dislocation as an uncommon late complication of THA that can impact, or be exacerbated by, the rehabilitation of other conditions. Uniquely of note, it can even present insidiously as recurrent, painless, and self-reducible.

Conclusions: Recurrent prosthetic dislocation and subluxation should be considered in patients with history of THA who develop hip instability and symptoms similar to snapping hip syndrome. Imaging is best obtained when symptomatic and hip precautions should be initiated early, especially if undergoing concurrent rehabilitation.