Lacertus Syndrome: an Outcome Analysis After Lacertus Release

PURPOSE: The lacertus fibrosus or bicipital aponeurosis is a sheet of ligamentous tissue just distal to the elbow joint and can be a compression point for the median nerve. Essentially, lacertus syndrome is a subset of pronator syndrome and an uncommon diagnosis by itself. Surgical release of the lacertus consists of a small 2-cm incision that can be performed under local anesthesia. This study aimed to evaluate the outcome of lacertus release in resolving median nerve symptoms.

METHODS: This retrospective study was performed at Prince Court Medical Centre, Kuala Lumpur, Malaysia, from January 2020 until June 2021. Ninety-three patients who presented with numbness of fingers, hand, or upper limb; forearm pain; and muscle weakness. They were diagnosed with lacertus syndrome on the basis of local tenderness at the lacertus fibrosus with either weakness of flexor pollicis longus and flexor digitorum profundus of the index finger or paresthesia over the thenar eminence. The patients underwent 3 months of hand therapy, and those with no symptom improvement were offered lacertus release performed by a single surgeon. The surgical technique consists of a surgical incision starting from a point 2 cm distally and 2 cm radially to the medial epicondyle. The incision projects 2 cm distally in an oblique fashion toward the radial styloid. A wide-awake local anesthesia no tourniquet (WALANT) technqiue was utilized and 20 mL of local anesthesic was injected subcutaneously around this region at least 20 minutes before the surgery. Careful dissection was made subcutaneously, and the lacertus fibrosus was identified as a thickened, shiny white structure and released. The Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, grip strength, and pinch strength were tested before and after surgery. At 6 months after surgery, the QuickDASH score was again assessed with a WALANT satisfactory questionnaire.

RESULTS: A total of 93 patients were included in the study. The mean age of the patients was 38.7 years, and most were women (77.4%). The mean operating time was 70 minutes. The mean preoperative QuickDASH score was 53, which significantly reduced immediately after surgery to 7.8 (P < .001) and remained low at 6 months after surgery (10.6). The mean grip strength showed a significant increase from a preoperative mean of 16 kg to a postoperative mean of 24 kg (P < .001). Pinch strength also significantly increased from a preoperative mean of 9 kg to 13 kg after surgery (P < .001).

CONCLUSIONS: Lacertus syndrome remains an underdiagnosed disease that can be treated efficiently with a directed minimal surgical incision under wide-awake local anesthesia. Lacertus release appears to significantly reduce pain and numbness with markedly improved hand grip and pinch strength. The corresponding QuickDASH scores also improved significantly after surgery. This study is vital to our understanding of proximal median nerve entrapment and to accurately diagnose it.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.