Flexor Carpi Radialis Brevis Resection for Treatment of a Distal Radius Fracture: A Case Report

Surgical Treatment of Distal Radius Fractures Complicated by Concomitant Flexor Carpi Radialis Brevis: A Case Series and Surgical Techniques

Introduction

The flexor carpi radialis brevis (FCRB) is a rare anatomical variation, with a reported prevalence ranging from 0.9% to 8.7%. Our previous report showed three cases of FCRB in distal radius fracture (DRF) and found that hypoplastic pronator quadratus (PQ) adjacent to the FCRB muscle made it difficult to cover a volar locking plate (VLP). As we subsequently experienced additional six FCRBs, we report on new findings and surgical tips.

Case Report

VLP fixation was performed on DRF with FCRB in nine limbs of eight patients. The prevalence was 2.9% (9 of 310 limbs). Of the seven patients that underwent unilateral surgery, six were muscle type and one was tendon type. One patient who underwent bilateral surgery had a muscle type on the left and a tendon type on the right. In three muscle types, as the FCRB muscle belly was widely attached to the radial side of the radius and the radial side of the PQ was hypoplastic, postoperative covering of the plate by repair of the PQ was impossible. Then, in two of those cases, the PQ and FCRB were sutured and the plate was covered. FCRB muscle could be retracted to the radial side in all cases. One patient with a tendon type had a ruptured tendon, which was left unrepaired. All patients had no postoperative problems.

Conclusion

In the muscle-type FCRB, the muscle should be retracted to the radial side for VLP fixation. The muscle belly might occupy the radial side of the radius, and the PQ might be hypoplastic and unrepairable. However, the plate can be covered by suturing the PQ and FCRB.

Surgical Exposure Technique for Volar Locking Plate Fixation of Distal Radius Fractures in Patients with Flexor Carpi Radialis Brevis Muscle Anomaly

The flexor carpi radialis brevis (FCRB) muscle, considered a rare anomaly, is not well known among orthopedic surgeons. The indications for volar locking plates to treat distal radius fractures have recently expanded, and, as a result, encounters with the FCRB are becoming more common. However, few studies have described how to retract an FCRB. Here, we describe seven of 264 patients with FCRB who underwent surgery for distal radius fractures. In one case, the retracted FCRB interfered with the internal fixation. The presented cases demonstrate that the radial retraction of an FCRB with a large muscle belly enables favorable exposure of the distal radius.