Proximal patellar tendon injury with avulsed periosteal sleeve: A case report and long-term follow-up

Introduction: Acute patellar tendon injuries in children are rare but increasing due to more high-energy sports participation. These injuries often involve bony fractures, with isolated tendon avulsions being uncommon. Timely diagnosis and surgical intervention are essential to restore knee function and pre-injury activity levels. Case presentation: A 12-year-old male student-athlete was brought to the hospital after his right knee buckled while playing football. He exhibited significant tenderness, swelling, and an inability to actively extend the knee. Clinically, a palpable gap below the inferior pole of the patella was detected. Discussion: Initial X-ray imaging was inconclusive. MRI confirmed a proximal patellar tendon avulsion from the inferior patella, with a narrow soft tissue sleeve attached to the distally retracted tendon. No bony avulsion or was found. Interestingly, intraoperatively, there was a complete avulsion of the periosteal sleeve covering the patella. Transosseous suture repair with suture anchor augmentation was performed. Followed by full reattachment of the periosteal sleeve. Three years post-surgery, the patient became a professional basketball player with full knee motion, no pain or instability, and excelled in high-intensity activities without limitations. Conclusion: Isolated proximal patellar tendon injury without bony avulsion is rare, and its association with complete periosteal sleeve detachment is exceptionally uncommon. The combination of transosseous repair and suture anchor augmentation ensured long-term stability. This approach effectively distributed tensile forces, minimizing the risk of re-injury and repair failure. A tailored rehabilitation ensured full knee recovery, with longterm follow-up confirming a return to professional sports without limitations.