Driver of a car involved in a road traffic accident presenting with an open knee fracture and dislocated patella.
A 23 year old man, driver of a car was involved in a head-on collision with an articulated lorry. He presented to casualty with a dislocated right patella associated with an open wound of his right knee. Initial clinical examination revealed a tense haemarthrosis of the knee with an opened distal femoral fracture presenting as a tranverse wound across the distal right thigh. There was no distal neurovascular deficit. Radiograph of the knee and showed a hoffa fracture which involved a fracture of the lateral femoral condyle which has displaced laterally taking along the patella with it. The patient was taken to theatre immediately ( 2 hours following the injury). Thorough washout of the knee was performed and the fracture was fixed temporarily with k-wires followed by 3 cannulated lag screws to fix the lateral condyle. The patient was started on anticoagulant and intravenous antibiotics. Mobilization was started after 48 hours. He was discharged 4 days following the surgery. Full weight-bearing was allowed after six weeks. Three months after surgery the patient has full range of knee movements with no ligamentous laxity. Radiograph showed good bony healing with no avascular necrosis of the condyle.
Unicondylar fractures of the femur in the coranal plane was first described by Hoffa in 1904. These are rare injuries. They are usually isolated injury to the involved femur and lateral condyle fractures are more common than medial fractures. Axial loading on the lateral remoral condyle with the knee in 90 degrees or more of flexion produces the tangential fracture patterns. This fracture essentially separates the patellofemoral joint from the tibiofemoral joint causing high shear forces on weight bearing. In addition, hoffa fractures are intraarticular fractures and therefore anatomical reduction and internal fixation is essential. Examination usually reveals an effusion and the neurovascular status should be assessed as these are high-energy injuries. AP and lateral radiographs can be unimpressive in the undisplaced fractures. Appearance of varus and valgus malalignment on the AP view is associated with the shortened femoral condyle. The femoral condyles are not superimposed on the true lateral view. Holmes et al used a standardized surgical approach and used optimally positioned screws placed perpendicularly to the fracture plane with good outcome.
Hoffa fracture
From the provided knee X-ray images (including AP, lateral views, and postoperative images), a coronal fracture line is visible in the lateral condyle of the distal femur. Some fracture fragments are malpositioned, indicating articular surface involvement, consistent with the radiographic characteristics of a Hoffa fracture. In the postoperative images, the fractured fragment has been stabilized with fixation screws, and the overall alignment is acceptable. Significant soft tissue swelling is noted, in line with an open injury and post-traumatic changes. Additionally, there are signs suggestive of previous patellar subluxation or dislocation, indicating a high-intensity injury mechanism.
Combining the history of high-energy trauma (traffic accident), open injury, clinical symptoms (severe swelling, deformity, functional impairment, and muscle strength limitation of the knee), and radiographic characteristics (coronal fracture of the lateral femoral condyle involving the articular surface), the most likely final diagnosis is:
Hoffa Fracture (Coronal Plane Fracture of the Lateral Distal Femoral Condyle).
If necessary, CT or MRI may be performed for accurate evaluation of cartilage or ligament injuries. In cases of severe soft tissue injury or concomitant peri-knee ligament damage, a multidisciplinary team assessment is advisable.
1. Emergency Management and Surgical Strategy
For this type of open Hoffa fracture, urgent management of the wound, infection prophylaxis, and prompt realignment of the fracture are generally required. The main surgical approach is open reduction and internal fixation (ORIF). Because the articular surface of the distal femur is involved, anatomical alignment and stable fixation are crucial to preserving joint function. For open fractures, thorough debridement and secure stabilization should be ensured intraoperatively, with vigilant monitoring for postoperative infection.
2. Key Points for Recovery and Rehabilitation
Since this fracture and the resultant surgical intervention affect the articular surface, early initiation of appropriate rehabilitation is recommended, under medical advice and limited by individual tolerance:
3. Individualization and Safety Precautions
• For younger patients with good bone quality, a relatively aggressive rehabilitation program may be considered, yet continuous close observation of fracture healing is necessary.
• Regularly assess the wound site and surrounding soft tissues for signs of infection. Treat promptly if suspicious findings arise.
• Gradually increase exercise volume and joint loading. If significant pain, swelling, or compromised function occurs, adjusting or pausing the rehabilitation plan may be warranted.
This report is a reference medical analysis based on the current imaging data and medical history. It cannot replace an in-person consultation or professional medical advice. Actual treatment plans should be tailored to the patient’s specific situation and developed by a professional healthcare team.
Hoffa fracture
