Isokinetic Strength Testing Following Intramedullary Nailing of Tibial Shaft Fractures Predicts Time to Recovery and Return of Muscle Strength in the Injured Extremity: A Prospective Case Series

Background: The speed and degree of functional recovery over time after surgery for tibial shaft fracture has been previously described using subjective methods. Questions/Purpose: This study aimed to quantitatively measure recovery of isokinetic strength in the injured leg after surgical repair of isolated closed tibial shaft fracture. Methods: In this prospective case series, patients were recruited after intramedullary nailing for isolated closed tibial shaft fracture at an academic medical center from January 2012 to December 2015. Recovery of isokinetic strength was quantified using an isokinetic dynamometer. Eight measures of isokinetic strength at 3, 6, and 12 months’ follow-up were used to compare strength in the injured leg to the healthy leg. Results: In 36 patients recruited, there was a significant difference in strength between the healthy and injured legs at 3 months for seven of the eight metrics used, at 6 months for five of the eight metrics, and at 12 months for none of the eight metrics. Observing recovery of strength longitudinally, we saw significant improvement between 3 and 6 months for four of eight metrics and overall between 3 and 12 months for five of the eight metrics. All four metrics that showed a significant improvement between 3 and 6 months involved plantar flexion. No metrics showed significant improvement between 6 and 12 months. Conclusions: Patients exhibited equal strength between their healthy and injured legs at 12 months after surgery. Improvement in strength occurred to a greater extent between 3 and 6 months after surgery than between 6 and 12 months. Plantar flexion appeared to improve more rapidly than dorsal extension.