[Replacement arthroplasty of paralytic hip. Apropos of 18 cases]

Frequency of hip impairment, with sub-luxation or dislocation, during evolution of neuromuscular diseases depends on intensity and spreading of palsy. At the end of growth or at the beginning of adult life, secondary arthritis can induce pain and lack of mobility. The importance of the chondropathy and irreducible lack of congruence may doom to failure a conservative articular or periarticular surgery. Total hip arthroplasty is an alternative, but the risks of dislocation, ectopic ossifications and infection make often refute this indication. We report our experience of total arthroplasty for paralytic hip, about 18 cases.

We reviewed retrospectively 14 consecutive patients with neuromuscular disease, who had 18 total arthroplasties of paralytic hips. The origin of neuromuscular disease was cerebral for 7 patients (6 cerebral palsy: 4 spastic or athetosic tetraplegias, 1 spastic diplegia, 1 hemiplegia; 1 head trauma), 6 medullar disorders (1 Friedreich disease, 2 acute anterior poliomyelitis, 1 vascular injury, 1 malformative spine with sacral agenesis and 1 cervical spine trauma) and 1 muscular affection (Steinert disease). Mean age of the patient was 40 year old (19 to 64). Mean follow up was 5 years. Intensity and diffusion of weakness were variables, compatible with gait with or without help for 11 patients, and for 3 patients with sitting posture and transfer. The coxopathy, with pain stiffness and vicious attitudes, induced the loss of gait or sitting posture and transfer. The goal of the arthroplasty was the restitution of the initial function. 11 hip had previous surgery, with infection in 2 cases. Arthritis was secondary to hip palsy in 14 cases (4 dislocations, 6 subdislocations, 3 complications of surgery of paralytic hip dislocation in childhood, 1 nervous arthropathy), and independent of palsy in 4 cases (1 femoral head avascular necrosis ans 3 primary arthritis). The prosthesis were LFA Charnley Kerboull in all cases except 1. We used transtrochanteric approach.

Mean follow-up is 5.6 years. Functional initial goal has been obtain in all cases. Ectopic ossifications occurred in 3 cases, without functional consequence. One acetabular loosening occurred after 13 years and has been reoperated on. There was no polyethylene wear. We noticed 1 mechanical and 2 chemical femoral loosening. Prosthetic dislocation occurred in 4 cases, always during the 4 post-operative months, without recurrence after this critical period. There were no infection.

If gait is possible, there is no satisfactory alternative to total hip arthroplasty. In absence of gait, total hip arthroplasty gives also the best functional results. Girdlestone procedure is not indicated because it will induce the loss of transfer and side effects as ascension of proximal femur with recurrence of adduction bringing out pain and sometimes scabs.

Total arthroplasty of paralytic hip induced restitution of initial function for all patients and an acceptable rate of complication after strict selection of patients and indications, specific operative technique and rehabilitation for each patient. This results encourage us to carry on with this therapeutic orientation.