2.1

This is a retrospective data analysis of patients who were prospectively documented in our clinical information system. Patients provided written consent to use their data for research purposes.

Patient files were reviewed and all who were treated with the Z-type SOPP between June 2020 and November 2023 were selected for assessment by a senior foot and ankle surgeon.

Patients were eligible if they had undergone the Z-type SOPP because of persisting pain or discomfort related to an overlength of any of their lesser toes after conservative methods (i.e. shoe adjustment) had been exhausted. The indication for Z-type SOPP was based on the clinical signs of any elongated minor toe or toes with concomitant pain and soft tissue or nail irritation; toe overlength (specifically of the proximal phalanx) was confirmed on a standard dorsoplantar x-ray. Patients with any prior surgery of the minor toes were excluded as well as those with additional surgical procedures at the midfoot, hindfoot or ankle.

2.2

Since June 2020, the Z-type SOPP was implemented at our tertiary orthopedic facility by the primary author for patients indicated for shortening of their affected lesser toes. While fusion of the PIP joint was the benchmark for lesser toe shortening, we regularly observed active patients, in particular, who were dissatisfied with postoperative toe stiffness. By developing this joint-preserving method, we wanted to provide an opportunity to preserve toe mobility of our active patient collective.

Surgeries were completed by two consultant foot and ankle surgeons on all eligible digits (i.e. second, third and fourth toes were considered regardless of the first two being most often affected). Briefly, all patients were placed in a supine position and received an ankle block based on our standardized regional anesthesia protocol. A skin incision of approximately 1.5 cm was made dorsal to the proximal phalanx. Subcutaneous fat tissue was then dissected and the extensor tendon exposed, spared and retracted laterally. The dorsal aspect of the proximal phalanx was then exposed and a Z-shaped osteotomy was cut using a 4 mm oscillating saw (Stryker, Biberist, Switzerland) ( Fig. 1 a). Specifically, proximal and distal bone segments, divided by a linear medial cut, were resected according to the desired amount of shortening ( Fig. 1 b and c) such that the two articulating parts could finally slide into each other to achieve the desired length of the base ( Fig. 1 d). Based on the surgeon’s discretion and in consideration of each individual patient and their affected toe, the amount of shortening was achieved such that the final toe length would share symmetry (or harmonious proportion) with the length of the other toes. Bone resection, ranging from 4 mm to 11 mm, was estimated based on clinical examination and preoperative standard dorsoplantar radiographs to primarily achieve a length matching that of the first toe, while retaining the overall length symmetry among all toes. Because the resultant bone fragments in the Z-shaped formation lock into one another, there was no requirement for plate fixation. The interlocking bone segments were stabilized with one or two bicortical 1.2 mm screws (Stryker, Biberist, Switzerland) ( Fig. 1 e) followed by skin closure with a resorbable suture. Diagrammatic representation of the entire procedure is also outlined in Fig. 2 .

Z-type shortening osteotomy in situ for treatment of an elongated lesser toe on the right foot of a 24-year old female. (a) The proximal phalanx of the first lesser toe is exposed via a dorsal approach and the Z-shaped osteotomy is cut using an oscillating saw beginning with the linear central cut; (b) proximal and distal bone segments are then cut and (c) removed before (d) sliding the bone joints into each other and (e) stabilizing the osteotomy with screws.

Diagrammatic representation of the Z-type shortening osteotomy of the proximal phalanx. Blue Z-shaped lines indicate the initial cuts made to create the osteotomy (far left) with bone segment cuts marked by the dotted lines (second from left). Upon bone removal, the sections articulate into each other (second from right) and are secured with screws (far right). The blue arrow presents the amount of shortening achieved after the osteotomy is aligned and stabilized.

2.3

Patients were instructed to walk with full weight bearing in a surgical rigid sole-fitted shoe for three to four weeks. From the third postoperative week, MTP and PIP joints could be mobilized within pain tolerance levels to prevent stiffening. The first postoperative radiographic follow-up was scheduled at six weeks and patients were allowed to move without restrictions and return progressively to their normal sports activities.

Baseline data on the affected side, previous forefoot surgeries, number of toes treated and the extent of toe shortening were summarized. The latter was determined by comparing phalanx lengths (i.e. distance between proximal and distal joint lines) on pre- and 6-week postoperative dorsoplantar radiographs. We also investigated the occurrence of all complications such as infection, wound dehiscence and nonunion that were documented in our clinical information system throughout the standard follow-up period of one year. Lastly, patient satisfaction with the surgical outcome at one year post-SOPP, as rated on a 4-point Likert scale ranging from very dissatisfied (0) to very satisfied (4), was reported. Patients were also asked whether they experienced any functional restrictions with their foot since the surgery.

All baseline and outcome data analyses were exploratory and standard descriptive statistics were presented, where applicable.