Early Fracture of a Bioabsorbable Tibial Interference Screw After ACL Reconstruction With Subsequent Chondral Injury

Abstract

Graft fixation in anterior cruciate ligament (ACL) reconstruction is commonly performed with bioabsorbable devices. This article presents a case of a broken bioabsorbable tibial interference screw (Gentle Threads; Biomet, Warsaw, Indiana) that presented as an intra-articular loose body 4 months after ACL reconstruction with posterior tibialis tendon allograft. A 19-year-old man presented with symptoms of pain and catching for 1 week but reported no history of trauma. The broken screw tip was identified on magnetic resonance imaging examination, and the remaining screw appeared to be overinserted into the tibia. During arthroscopic removal, a 10-mm screw tip was found in the lateral gutter. The ACL graft was found to be well fixed, but small areas of chondral damage were found in the patellofemoral and medial compartment. The patient's symptoms resolved postoperatively. To our knowledge, this is the earliest report of a broken bioabsorbable interference screw and only the second report of subsequent chondral injury due to intra-articular migration. Although rare, late breakage and intra-articular migration of bioabsorbable interference screws should be considered during the postoperative evaluation of any patient with pain or mechanical symptoms, regardless of trauma. This case also supports the importance of both measurement of tibial tunnel length and inspection of the intercondylar notch following interference screw insertion. Orthopedic surgeons performing ACL reconstruction must be aware of this possible complication and its potential for devastating chondral injury.