Changes in length of the first ray with two different first MTP fusion techniques: a cadaveric study

BACKGROUND: First metatarsophalangeal joint (MTP) fusions are performed as salvage procedures for a variety of conditions ranging from osteoarthritis, rheumatoid arthritis, hallux valgus, and failed first MTP arthroplasty. A number of bone preparation techniques have been described to fuse the first MTP joint, with varying degrees of success. The aim of this study was to characterize and compare the average shortening of the first ray with a conical reamer fusion technique versus flat bone cut technique. MATERIALS AND METHODS: Six paired cadaver feet were divided into two groups with one foot from each pair in each group. Preoperative first ray lengths were measured radiographically. Each group then underwent arthrodesis of first MTP joint with one of two different bone cut techniques: flat cuts or conical reaming. The postoperative lengths of the first rays were measured and the data analyzed using a two-tailed Student's t-tests. RESULTS: The average shortening that occurred in both groups after the procedure was 7.1 mm for the flat cut group (Group I) and 5.7 mm for the machined conical reaming group (Group II). Comparing both groups, there was no statistically significant difference in the shortening between the groups. CONCLUSION: Both flat bone cut and conically reamed techniques caused shortening of the first ray after first MTP fusion. However, there was no statistically significant difference in the postprocedure lengths of the first ray between the two groups. CLINICAL RELEVANCE: Neither technique is more likely to lead to transfer metatarsalgia since the shortening was similar.