Maintenance of First Ray Length after First Metatarsophalangeal Joint Distraction Arthrodesis Using Allograft Discs: A Statistical Analysis

Abstract

Category: Midfoot/Forefoot Introduction/Purpose: The first metatarsophalangeal joint (MTPJ) is one of the most common locations for arthritis in the foot. When conservative methods fail, two main surgical treatment options exist, fusion or joint implant. For various reasons these surgeries can fail leaving relatively few salvage options. A common salvage option is the first MTPJ distraction arthrodesis. Use of allograft discs to decrease surgical time and donor site morbidity has become an increasingly popular option for MTP distraction arthrodesis. The purpose of this study was to look at the maintenance of the first ray length in first MTPJ distraction arthrodesis using allograft discs. Methods: We reviewed 14 patients who underwent first MTPJ distraction arthrodesis, measuring first ray length at the first post- operative weightbearing radiograph and most recent weightbearing radiograph. Average follow up was 12.75 months between radiographs. Results: Average shortening was 3 mm on the lateral measurements and 2.3 mm on the AP measurements. CT verified overall nonunion rate was 43% whereas, symptomatic nonunion rate was 21%. Conclusion: Amount of shortening and graft size did appear to have a positive correlation. Union rate did not affect shortening of first ray, but revision for a failed implant arthroplasty did correlate with increased shortening compared to revision for a failed first MTPJ fusion. Our data suggests a 2-3 mm shortening of the first ray can be predicted over the first 12 months after a first MTPJ distraction arthrodesis using allograft discs. Longer term studies with larger patient populations, and a comparative study to cortical autograft would provide more accurate insight to outcomes of first MTPJ distraction arthrodesis.