Radiographic Assessment of Diaphyseal Proximal Phalangeal Shortening Osteotomy for Correction of Hammertoe Deformity
Authors: Bastias Gonzalo , Sage Katherine , Schon Lew 
Published: September 2018

Category: Lesser Toes Introduction/Purpose: Hammertoe deformities are a result of imbalance between static and dynamic stabilizers of the lesser toes. Flexor-to-extensor tendon transfer and PIP joint arthrodesis/arthroplasty are the gold standards of treatment. Tendon transfers are associated with stiffness, edema and recurrence. PIP arthrodesis/arthroplasty sacrifices the PIP joint producing loss of both motion and toe grip. Phalangeal sustraction osteotomies have been proposed for correcting these deformities by theoretically relaxing the surrounding soft tissue structures and correcting the hammertoe deformity at the PIP joint. We present the results of a new joint sparing procedure consisting on a Diaphyseal Proximal Phalangeal Shortening Osteotomy (DPPSO) with resection of a 3-4 mm cilindrical bone section. Methods: Retrospective study. Review of medical records of patients who underwent phalangeal shortening osteotomy for hammer toe correction from 2010 to 2016 by the senior author (L.S.). Patients with previous surgery on the toe were excluded of the study as well as patients with incomplete radiological follow-up. Demographic and comorbidities data were noted as well as postoperative complications and secondary procedures. We performed a radiographic analysis of preoperative and postoperative x-rays-Union was defined as the existence of brigding of at least 3 cortices on the osteotomy site. Preoperatively and 6 months follow up x-rays were additionally analyzed to obtain the following measurements (Figure 1): Frontal anatomic angle (medial) FAAm Lateral anatomic angle (plantar) LAAp Frontal proximal interphalangeal angle (medial) mFPIA Lateral interphalangeal angle (plantar) pLIPP Statistical analysis: t-test for paired samples to compare preoperative and postoperative angles. Results: Forty-five toes (31 patients) were included in the study. The mean age of the patients was 59,5 years and the mean follow-up was 27.9 months (range:12-52). Concomitant procedures were performed on 29 patients, most commonly Hallux Valgus correction. All patients evolved with radiographic union at an average 11,2 weeks. Two patients presented with delayed healing (15 and 19 weeks). Complications were present on 4 toes corresponding to Superficial infection (3 patients) and a symptomatic floating toe (1 patient). There were not recurrences in this group. Radiographic measurements showed no significant differences between the preoperative and postoperative mFFA (p:0,43), pLAA (p:0,239) and mFIA (p:0,239). In the other hand, the Plantar lateral interphalangeal angle (pLIA) that corresponds with the hammertoe deformity, was significantly corrected (p<0,05). Conclusion: DPPSO is a safe and reproducible procedure with a low rate of complications. This procedure has a corrective effect on the PIP joint on the sagittal plane, reducing significantly the plantar lateral interphalangeal angle and consequently the hammertoe deformity. There was no significant effect on the PIP joint on the coronal plane and neither on the anatomical axis of the proximal phalanx in the frontal and lateral planes, therefore not producing secondary deformities of the toe.The location of the osteotomy improves bone contact and anatomical alignment of the toe while obtaining a significant correction power of the deformity.