Isolated Partial Femoral Avulsion Fracture of the Posterior Cruciate Ligament in Adults.

Objective: To investigate the manifestation, mechanisms, and treatment of isolated partial femoral avulsion fractures of the posterior cruciate ligament (PCL) in adults.

Methods: From January 2011 to December 2018, we retrospectively reviewed the clinical data of three patients with isolated partial femoral avulsion fractures of the PCL who were admitted to our institution. All of these patients were admitted to our emergency department within 24 h after injury. After physical examination and radiographs were taken and reviewed, all patients were admitted and underwent surgical treatment. In a 26-year-old man who underwent arthroscopic surgery through the traditional medial and lateral approach before finally converting to open surgery with the posterior approach, the fragment that was finally removed was partially attached to the PCL. In the other two patients, women aged 63 and 68 years, who underwent arthroscopic surgery via the traditional medial and lateral approach, the fragments were large and attached to most fibers of the PCL. We fixed the fragments using hollow screws in arthroscopic view. In addition, in the 63-year-old patient, an anchor was embedded to restore the tension of the PCL. Four weeks after surgery, the patients started to wear long leg braces in full extension with the tibia blocked up by cushion. Physical examinations were conducted and radiographs were taken preoperatively and at 4 weeks and 3 months after surgery to evaluate the condition of the injury. The range of motion and the Lysholm knee scoring scale for the knee joint were compared before and after the surgery.

Results: For the three patients, the radiographs taken at 3 months postoperatively showed that the fixation of the screws did not fail, and the subchondral bone was generally normal compared to the preoperative radiographs. CT scanning at 3 months after surgery showed that the fracture healed in the original position of the avulsion site. For all patients, the affected knees presented as stable at physical examination 3 months after surgery; the Lachmann test and the anterior drawer test results were negative. In addition, the flexion-extension, internal rotation, and external rotation were approximately 0°-130°, 0°-30°, and 0°-40° in the 26-year-old patient, respectively. The flexion-extension, internal rotation, and external rotation were approximately 0°-100°, 0°-20°, and 0°-35° for the 63-year-old patient, respectively. The flexion-extension, internal rotation, and external rotation were approximately 0°-100°, 0°-15°, and 0°-20° for the 68-year-old patient, respectively. There was no pain or only little pain 3 months after surgery. There was no swelling or discomfort at the 3-month follow up. The Lysholm knee scores of the 68-year-old, 63-year-old, and 26-year-old patient were 80, 87, and 95 at 3 months after surgery, respectively, which were obviously improved postoperatively.

Conclusion: The manifestation of isolated partial femoral avulsion fractures of the PCL in adults is often related to the injury mechanism, and surgery is essential for the treatment of these patients. Most of these fractures can be repaired by arthroscopic surgery, but some have to be treated by open surgery.