A Comparison of the Effects of First Metatarsophalangeal Joint Arthrodesis and Hemiarthroplasty on Function of Foot Forces using Gait Analysis

Abstract

Background: Arthroplasty or hemiarthroplasty for hallux rigidus of the first metatarsophalangeal (1 st MTPJ) is thought to lead to greater joint motion and improved gait function. There have been no studies to compare the effects of 1 st MTPJ arthrodesis and hemiarthroplasty on joint kinetics, kinematics and plantar pressures of foot and lower limb. Methods: A retrospective, case series pilot study approximately 22 months post operation. Subjects had either arthrodesis or a NorthStar HemiCAP hemiarthroplasty for osteoarthritis of the 1 st MTPJ. All had plantar pressure, kinetic and kinematic gait analysis as well as the Foot and Ankle Outcome Score (FAOS), and 1 st MTPJ range of motion (ROM). Results: For the hemiarthroplasty subjects the mean ROM on the non-operated 1 st MTPJ was 49 0 (SD23) but only19 0 (SD16) on the operated side. Kinetic and kinematic results for both operations were similar. Plantar peak pressure data showed that the arthrodesis group took more pressure under the 1 st MTPJ in the stance phase. The arthrodesis group had higher FAOS scores (mean 95.6 SD 5.1) than the hemiarthroplasty group (mean 72.2 SD 18.8) indicating more satisfaction with their surgery. Conclusions: Arthrodesis of the 1 st MTPJ better FOAS scores, improved peak plantar pressure over the medial foot compared to a 1 st MTPJ hemiarthroplasty. There were minimal differences in kinetic and kinematic data. Hemiarthroplasty patients had considerably reduced 1 st MTPJ ROM compared to their non-operated side. We conclude that the North Star HemiCAP cannot be recommended at this time for the management of hallux rigidus. Arthrodesis remains the surgical treatment of choice.