Comparison Between Different Techniques of Central Slip Reconstruction for Correcting Extensor Lag in Vascularized Toe Proximal Interphalangeal Joint Transfers

Abstract

Objective: From our previous study, deficiency of the central slip was identified in more than 86% of the lesser toes. This was correlated with the extension lag of proximal interphalangeal joint (PIPJ) after vascularized joint transfers (VJT). Subsequently, we demonstrated our clinical experiences that extension lag associated with poor central slip formation in the toe can be corrected using central slip reconstruction with the Stack method. The Stack procedure involves the dorsal passing of a distally based flexor digitorum superficialis (FDS) slip through the middle phalangeal base. To drill an extra hole along with extensive manipulation of periosteum can increase the risk of damage to the perfusion of the transferred joint. As such, we present a novel, simple, and effective technique to correct extensor lag during VJT and compared it with our prior VJT with the Stack method. Methods: In our new technique, the lack of a central slip in type I toes can be corrected by anchoring the lateral bands to the middle phalanx of the transferred PIPJ. When transferring a PIPJ of the second toe for the reconstruction of PIPJ defect in a finger, osteosynthesis is first performed passing cerclage wire through 2 holes drilled through the distal and proximal ends of the joint complex. Re-creation of the extensor insertion to the middle phalanx is performed by anchoring the lateral bands down to bone with sutures. Tenorrhaphy of extensor digitorum longus (EDL) to central extensor of the finger at zone IV is performed utilizing Pulvertaft weaving. After the surgery, this group of patients followed the same rehabilitation protocol as those with the Stack method. The arc of motion of the PIPJ was measured in the latest clinics. Results: The use of this novel technique in our institution has seen equivalent results in range of motion when compared with the use of Stack’s technique (61.0 ± 19.6° vs. 54.4 ± 11.8°) in the reconstruction of PIPJs using VJTs. This technique is also safe and quick to perform when compared with our prior adopted method in central slip reconstruction, and no injury to neurovascular structures have been seen in our institution. The anchored lateral bands sufficiently enhances the axial pull of the extensor mechanism and corrects the inherent extensor lag of the type I toe joints. Only by correcting this inherent extensor lag can we maximize the full potential range of motion of the toe PIPJ. Conclusions: Our method achieves similar outcomes to the Stack procedure, but has the advantage of minimizing addition bone drilling and soft tissue manipulation, hence making the procedure markedly easier to perform.