Percutaneous Bunionette Correction without Fixation: Clinical Results and Radiographic Evaluations Including Rotation of Metatarsal Head and Sagittal Angular Change of Fifth Metatarsal

Abstract

Category:Lesser ToesIntroduction/Purpose:Bunionette has been treated as an analogy of hallux valgus, and the surgical techniques are similar. However, only the anteroposterior image is generally evaluated pre- and postoperatively. There are few studies that evaluated on the lateral radiograph, and to the best of our knowledge, no study that evaluated changes in rotation of fifth metatarsal head. In percutaneous bunionette correction using a burr, shortening of fifth metatarsal and elevation of metatarsal head are inevitable. In addition, there is also the possibility of rotational change of metatarsal head without fixation.Methods:We evaluated 18 consecutive feet performed percutaneous bunionette correction without internal fixation. Mean age was 54.9 years. Mean follow-up was 10.1 months at least six months followup. On anteroposterior weightbearing radiograph, we measured the fifth metatarsophalangeal angle (MPA), fourth and fifth intermetatarsal angle (IMA), the fifth metatarsal head width (MHW), the lateral deviation angle (LDA) of the fifth metatarsal, and fifth metatarsal shortening. On the lateral weightbearing radiograph, we measured the lateral inclination angle (LIA) of the fifth metatarsal, the fifth distal metatarsal height (DMH), mid metatarsal height (MMH), proximal metatarsal height (PMH), and plantar bowing angle (PBA). To evaluate the rotation of the fifth metatarsal head, we devised a new original method measured at the medial tubercle location (MTL). Preoperatively and at the most recent follow-up visit, we applied the Japanese Society for Surgery of the Foot (JSSF) lesser scale and visual analogue pain scale (VAS).Results:Except for MTL, DMH and PMH, all parameters showed significant changes postoperatively.MPA, IMA and LDA reduced from 17.3 degrees to 6.4 degrees, from 9.9 degrees to 4.5 degrees, and from 2.3 degrees to -10.0 degrees, respectively. Shortening of fifth metatarsal was 2.5 mm. Despite not performing partial head resection, MHW decreased from 12.1mm to 11.4 mm. LIA decreased from 9.2 degrees to 6.1 degrees. MMH decreased from 11.6 mm to 10.9 mm. PBA decreased from 7.0 degrees to -1.3 degrees. Union was obtained at 6.9 weeks. MTL reduced from 3.4 to 2.8 but not significantly. However, MTL changed in 15 of 18 feet (83.3%) postoperatively. JSSF lesser scale improved from 66.7 to 97.8 points. VAS also improved from 3.6 to 1.0. One foot had a delayed union and an occasional pain.Conclusion:Percutaneous bunionette correction without fixation could achieved good clinical and radiographic results comparable with previously published outcomes of open and percutaneous surgery with fixation with less complication. The procedure could be adapted to different types of bunionette deformity. In this surgical method, bunionette is corrected in three dimensions.