Biomechanical comparison of tension band wiring and plate fixation with locking screws in transverse olecranon fractures.

BACKGROUND: Tension band wiring (TBW) is the standard method for treating transverse olecranon fractures, but high rates of complications and reoperations have been reported. Plate fixation (PF) with locking screws has been introduced as an alternative method that may retain the fracture reduction better with a higher load to failure. METHODS: Twenty paired cadaveric elbows were used. All soft tissues except for the triceps tendon were removed. A standardized transverse fracture was created, and each pair was allocated randomly to TBW or PF with locking screws. The triceps tendon was mounted to the materials testing machine with the elbow in 90° of flexion. Construct stiffness was compared 3 times. Then, the elbows underwent a chair lift-off test by loading the triceps tendon to 300 N for 500 cycles. Finally, a load-to-failure test was performed, and failure mechanism was recorded. RESULTS: The construct stiffness of PF was higher in the first of 3 measurements. No difference was observed in the cyclic test or in load to failure. Hardware failure was the failure mechanism in 8 of 10 TBW constructs, and all failures occurred directly under the twists of the metal wire. Hardware failure was the cause of failure in only 1 elbow in the PF group (P < .01). CONCLUSION: There was no difference in fracture displacement following fixation with TBW and PF with locking screws in transverse olecranon fractures. However, assessment of the mode of hardware failure identified the metal cerclage twist as the weakest link in the TBW construct.

An intact lacertus fibrosus improves strength after reinsertion of the distal biceps tendon.

PURPOSE: The importance of an intact lacertus fibrosus in distal biceps tendon injury is uncertain. This study aimed to assess long-term outcome following distal biceps tendon repair with focus on the significance of the lacertus fibrosus. METHODS: Thirty-six patients surgically treated for primary distal biceps tendon rupture were identified. Medical records were reviewed for patient demographics in addition to surgery-related data. All patients underwent a targeted clinical examination to assess elbow function and they completed a patient reported questionnaire. Radiographs were obtained at time of follow-up and evaluated for the presence of osteoarthritis (OA) and heterotopic ossification (HO). RESULTS: All patients were male. Median age at injury was 48 years (34-69) and median time of follow-up of was 71 months (23-165). All patients presented functional range of motion in the elbow. Median flexion strength was 76 Nm (45-135) (median 99% of uninjured side; range 66-128) with intact lacertus fibrosus and 70 Nm (43-124) (88%, 62-114) with torn lacertus fibrosus. Median supination strength was 6 Nm (3-11) (86%, range 36-144) with intact lacertus fibrosus and 8 Nm (3-17) (67%, 28-118) with torn lacertus fibrosus. No signs of OA were revealed, but three patients had major HO of which one patient had minor limitations in range of elbow motion. CONCLUSION: An intact lacertus fibrosus contributes to elbow strength and should be preserved in distal biceps tendon repair. LEVEL OF EVIDENCE: III.