Mid-term results of a first generation metatarsophalangeal hemiarthroplasty system for the treatment of hallux rigidus

L. McEntee, M.-C. Killen, P. Karpe, R. Limaye

Background: Hallux rigidus is a degenerative condition of the first metatarsophalangeal joint (MTPJ) of the great toe, which can result in significant pain and stiffness. Treatment using joint replacement, either by means of hemiarthroplasty or total arthroplasty of the metatarsophalangeal joint is becoming an increasingly popular option for patients with severe disease.

Aim: To evaluate mid-term functional and radiological outcomes of a widely used first generation resurfacing arthroplasty system in the treatment of hallux rigidus.

Method: Prospective review of patients from 2009 onwards. All patients were operated on by the senior author using the same first generation hemiarthroplasty prosthesis (HemiCAP®, Arthrosurface, USA) and surgical technique.
Radiological and clinical outcomes were assessed at 3, 6, 12 and 24 months post-operatively. Patients were assessed pre- and post-operatively on an outpatient basis for MTPJ range of motion as well as outcomes using AOFAS and visual analogue scale scores.

Results: 20 prostheses in 19 patients over a two year period. Mean follow-up was 18 months (range 12-24).
Mean AOFAS score improved from 38.66 pre-operatively to 74.93 at 12 months post-operatively. Mean VAS score improved from 9.95 pre-operatively to 4.05 post-operatively. There was radiological subsidence in one patient. 5 patients (26%) required revision to arthrodesis due to ongoing pain and stiffness.

Conclusion: Despite significant improvements in functional scores and positive radiological outcomes in most patients, we have seen high revision rates with this first generation prosthesis due to ongoing pain and stiffness. Since this study, there has been a redesign of this implant with the addition of a dorsal flange, but the first generation prosthesis still remains in use. Following our results, we have discontinued our use of this product in favour of either the newer generation hemiarthroplasty or total arthroplasty system for patients with severe hallux rigidus.