# Clinical application of the free anterolateral thigh chimeric muscle flap for reconstruction of composite tissue defects of the forearm and hand

## TL;DR

This paper shows how a specific muscle flap can effectively reconstruct complex injuries in the forearm and hand, improving function and reducing complications.

## Contribution

The study introduces the free anterolateral thigh chimeric muscle flap as a novel solution for composite tissue defects in the forearm and hand.

## Key findings

- The ALT-CMF flap achieved satisfactory functional recovery with a mean TAM score of 235.79°.
- Sensory recovery in transplanted flaps was comparable to the contralateral side.
- 75% of flaps survived without complications, with low donor-site morbidity.

## Abstract

Composite tissue defects (CTD) of the forearm and hand commonly result from industrial, agricultural, and traffic-related injuries and often involve multiple anatomical structures, making reconstruction challenging. Simple skin-flap coverage may leave deep dead space and fail to restore functional integrity. This study reports our experience using the free anterolateral thigh chimeric muscle flap (ALT-CMF) for CTD reconstruction and evaluates its effectiveness in achieving reliable defect coverage and functional recovery.

We retrospectively reviewed patients who underwent ALT-CMF reconstruction between February 2018 and January 2023. All patients had CTD of the forearm or hand and were followed for at least six months. Flap viability, postoperative complications, and donor-site outcomes were recorded. Digital functional recovery was assessed using the Total Active Motion (TAM) score. Two-point discrimination (2PD) were used to evaluate sensory recovery in the transplanted skin flaps.

Twenty patients (15 males, 5 females; mean age 39.40 ± 9.90 years) were included. During surgery, the median area of the harvested anterolateral thigh perforator skin flap was 80.0 (66.0–99.0) cm2, while the median area of the muscle flap component was 21.25 (20.00–30.00) cm2. All donor sites were primarily closed. Over a mean follow-up period of 15.30 ± 5.78 months, 15 flaps (75.0%) survived uneventfully, while 5 patients (25.0%) developed vascular crisis; four flaps were salvaged after urgent re-exploration, and one experienced complete necrosis. At the six-month follow-up, the mean TAM score was 235.79° ± 8.35°, indicating satisfactory recovery of digital mobility. 2PD testing demonstrated no significant difference in sensory recovery between the transplanted flaps and the contralateral side (19.42 ± 2.59 mm vs. 18.16 ± 3.20 mm, P = 0.063).

The ALT-CMF is an effective reconstructive option for composite tissue defects of the forearm and hand. By providing reliable soft-tissue coverage, eliminating dead space through its chimeric muscle component, and supporting functional restoration in terms of joint mobility and sensation. This technique enables one-stage reconstruction with low donor-site morbidity and promotes favorable limb recovery.