Heterotopic Ossification after Open Anchor Fixation of the Posterior Cruciate Ligament Avulsion in a Multiligament Injury of the Knee: A Case Report

INTRODUCTION: Heterotopic ossifications (HO) are a well-recognized but infrequently encountered condition. In the lower limb, the literature commonly reports the formation of HO around the hip after surgeries. However, HO is uncommon around the knee and a rare complication after open fixation of posterior cruciate ligament (PCL) avulsion fracture. CASE REPORT: Here, we describe a case of HO in a 42-year-old patient with multiligament injury, including PCL and arcuate ligament avulsion, partial ACL tear, and medial meniscus root tear with suspected vascular compromise. He underwent open reduction and internal fixation of PCL avulsion fracture and medial meniscus root repair after the injury. At a 6-week follow-up, a plain radiograph revealed posterior capsule HO which kept increasing over successive follow-ups compromising his knee function. The patient was not willing for any mode of intervention for the same at any given time. CONCLUSION: HO after open PCL avulsion fixation is an uncommon entity. This article sheds light on how open fixation of PCL bony avulsion in a multiligament injured knee could result in a HO.