POLY LACTIDE CARBONATE (PLC) INTERFERENCE SCREWS IN KNEE LIGAMENT RECONSTRUCTION SURGERY.

Abstract

Purpose of study: The aim of this study was to look at the clinical outcome of PLC interference screws in knee ligament reconstruction surgery.

Materials & Results: We prospectively followed up 60 patients who underwent primary anterior cruciate ligament (ACL) reconstructions using PLC (Calaxo; Smith & Nephew) screws to secure the graft in the tibial tunnel. [(35 male patients & 25 female). Average age 33.72 years]. In addition to the ACL, PLC screws were used to reconstruct the posterior cruciate ligament in one case and posterior cruciate ligament with the posterolateral corner in another three patients. Hamstring autografts were routinely preferred except in multiple ligament reconstructions, when allografts were also used.

25 (41.67%) patients presented with complications (synovitis in 10 patients, prominent tibial swelling in 21 patients and both in 7 patients). In comparison, no complications were noted in 60 other age and sex matched patients in whom PLLA (Bio RCI; Smith & Nephew) screws were used by the same surgeon.

The symptoms in the PLC screw group often settled conservatively and did not affect knee stability. 6 patients underwent exploration of the tibial tunnel site. A sterile white cheesy substance was noted which was removed, leaving an empty tibial tunnel. The ACL graft was found to be well attached to tibial tunnel in all cases. The PLC screw size did not have any correlation to the occurrence of complications. 2 patients required multiple washouts, one of whom developed a deep infection.

Conclusion: The degradation of PLC screws does not follow the gradual and controlled pattern demonstrated in the ovine model [Walsh WR et all, Arthroscopy. 2007 Jul;23(7):757–65. Comparison of PLLA and PLC interference screws in an ovine ACL reconstruction model.]. The unpredictable screw resorption, and the reaction to it can lead to serious clinical consequences.