Intramedullary Cortical Button Fixation Of Distal Biceps Tendon Rupture: Long-term Patient Outcomes

OBJECTIVES: No consensus currently exists for optimal distal biceps rupture fixation. Dorsal cortical button (DCB) and dual incision transosseous (DITO) provide the greatest biomechanical load-to-failure, permitting earlier mobilization to prevent arthrofibrosis. Both methods have associated complications, restricted range of motion (ROM) from heterotopic ossification and proximal radioulnar synostosis for DITO while DCB has increased incidence of cutaneous and posterior interosseous nerve (PIN) injuries despite different techniques to reduce their frequency. The intramedullary cortical button (ICB) fixation technique aims to decrease PIN palsy risk, decrease implant costs and provide strong tendon-bone fixation allow for early ROM. We set out to determine the long-term efficacy of this technique and any difference in complication rates including re-rupture. METHODS: 31 patients underwent ICB fixation of chronic and acute distal biceps tendon ruptures without allograft with more than 1 year follow up. 21 patients completed a questionnaire and Disabilities of the Arm, Shoulder and Hand (DASH) survey. Elbow and forearm ROM, cosmesis, pain, strength, motor nerve neuropraxia, cutaneous sensory changes and other complications were obtained from the chart and questionnaire. The ICB technique utilizes a 4cm transverse anterior incision 2cm distal to the distal antecubital flexion crease. The tuberosity is prepared, creating a clean, bleeding bony surface. A #2 high-strength braided suture is passed through the toggle hole at both ends of a Smith and Nephew Endobutton. A needle passes one suture pair in the 4.7mm hole and out the 2mm hole drilled with mild convergence in the distal and proximal tuberosity footprint with a 1.5cm bony bridge. This suture pair shuttles the Endobutton into the intramedullary canal, both limbs of each suture exits their respective hole. One limb from each suture is whipstitched proximally and back distally. Tensioning the free suture limb exiting the 2mm hole and tying to its free suture pair compresses the biceps stump against the radial tuberosity and secures the Endobutton against the intramedullary cortex at the 2mm hole. Finally the free suture limb exiting the 4.7mm hole is tensioned and tied to its suture pair limb, distributing tendon compression over the entire tuberosity footprint. RESULTS: At an average of 4 (1.3-7.4) years postoperatively, 81% were extremely and 10% very satisfied with their overall outcome. 81% reported no strength or ROM limitations, 76% had pain-free activity, 86% and 81% were extremely satisfied with postoperative elbow ROM and forearm ROM respectively. The mean DASH and sports DASH score were 3.52 and 2.5. Transient sensory changes were noted in the lateral antebrachial cutaneous nerve and superficial radial nerve distributions in 38% and 19% of patients respectively. Excluding workers compensation patients improved the percent of extremely satisfied patients to 93% and the average DASH score to 0.93. No biceps re-ruptures or PIN palsies were observed. CONCLUSION: The ICB technique provides secure distal biceps tendon fixation with excellent long-term patient satisfaction and comparable functional outcomes to existing fixation techniques with restoration of normative DASH scores. The ICB technique has a cutaneous nerve complication rate comparable to other single incision studies and no observed PIN palsies or wound complications were noted while decreasing the implant costs.