# Post-Market Clinical Follow-Up of the MAX Variable Pitch Compression Screw System in Foot and Ankle Surgery: Safety, Performance, and Patient-Reported Outcomes

## TL;DR

A study evaluated the MAX VPC Screw System in foot and ankle surgery, finding high bone union rates and good patient outcomes, though some device-related complications occurred.

## Contribution

This is the first post-market clinical follow-up study of the MAX VPC Screw System in foot and ankle procedures, providing real-world safety and performance data.

## Key findings

- High bone union rates of 86.1% at 6–8 weeks and 98.8% at ≥18 months were observed.
- Arthrodeses showed higher early union rates (91.5%) compared to fractures/osteotomies (80.6%).
- Device-related complications occurred in 67.9% of adverse events, with no recurrent mechanical failures.

## Abstract

Background/Objectives: Rigid interfragmentary compression is essential for primary bone healing following fractures, osteotomies, and arthrodeses of the foot and ankle. Evidence on the clinical performance of the MAX Variable Pitch Compression (VPC) Screw System (Zimmer Biomet, Warsaw, IN, USA) remains limited. This post-market, retrospective cohort study evaluated its safety, performance, and patient-reported outcomes. Methods: A single-center, consecutive series of patients treated with the MAX VPC Screw System for foot or ankle fractures, osteotomies, or arthrodeses between March 2018 and October 2023 was analyzed. The primary endpoint was radiographic and clinical bone union or joint fusion at 6–8 weeks and ≥18 months. Secondary endpoints included adverse events and functional outcomes using the Foot and Ankle Ability Measure (FAAM). Results: A total of 214 procedures were included (27 fractures, 80 osteotomies, 107 arthrodeses). Union was assessed in 209 procedures (97.7%) at 6–8 weeks and in 82 procedures (38.3%) at ≥18 months. Union rates were 86.1% at 6–8 weeks and 98.8% at ≥18 months. Early union was higher in arthrodeses (91.5%) than in fractures/osteotomies (80.6%). Adverse events occurred in 13.1% of procedures, 67.9% of which were device-related; no recurrent mechanical failures were observed. Mean FAAM scores were 92.3 (ADL) and 78.8 (Sports) for arthrodeses and 94.3 and 85.8, respectively, for fractures/osteotomies, at a mean FAAM follow-up of 2.9 years. Conclusions: The MAX VPC Screw System demonstrated high bone-union rates, favorable functional outcomes, and a moderate number of device-related complications. These results support its clinical use in foot and ankle surgery. However, the retrospective, single-center design limits generalizability, and prospective multicenter trials are warranted to confirm these findings.