3.1 Patient characteristics
A 38-year-old man injured his left leg in a car accident, sustaining a closed intraarticular fracture of the proximal tibia and open intraarticular fracture of the distal femur with extension to the diaphysis. A patellar fracture was observed in the ipsilateral knee. Two small open wounds were noted mainly on the anterior aspect of the mid-distal femur. The level of contamination was minimal, and there were no soft tissue defects that needed to be covered with a flap. The initial management consisted of debridement and application of skeletal traction. The soft tissue settled after a week. Physical examination and lower limb computed tomography angiography (CTA) confirmed that the neurovascular status was normal. This patient denied any previous illness or surgery history, and none of the family members had any inherited diseases.
Preoperative radiographs show a multifragmentary fracture of the distal femur involving both condyles and extending into the diaphysis. A sagittal split of the medial condyle was observed. Three-dimensional CT scans showed the extent and location of the articular fractures (Fig. 1). Furthermore, the medial condyle fracture was separated and displaced. Long-stage comminuted bone fractures of the femoral mid-distal segments are the most complex part of the operation. Supracondylar and shaft fracture of the left femur exposed Gustilo Anderson (GA) II and minor bone loss of the metaphyseal area was < 5%.
The distal femoral fracture was classified as type 31C3.3, and the patellar fracture was classified as type 34B2.2 (according to the AO and the Orthopaedic Trauma Association [OTA] system); the proximal tibia fracture was classified as type IV (according to Schatzker type).
3.2. Surgical procedures
Operative treatment was mandatory to restore the articular congruency and the overall alignment of the leg. Because this was an open fracture, debridement of the wound and skeletal traction were planned as the initial management. Intramedullary nailing was difficult to use because of fracture morphology. In this case, we chose the MIPO technique for the treatment of complex floating knee injuries (Fig. 2).
After induction of general anesthesia, the patient was positioned supine on a radiolucent table with both legs draped free and a support placed under the injured knee. The medial parapatellar approach was adopted, and decision making was dependent on the location of the sagittal fracture separation of the femoral medial articular surface. The medial parapatellar approach was also useful for fixation of an associated patellar fracture (34 B2.2). After the patella was repositioned, two 2.0-mm cortical bone screws were used to fix the patella fracture. Tibial fractures (Schatzker IV) were treated using the medial patella approach combined with the MIPO technique. Indirect percutaneous articular reduction with pointed reduction forceps was performed and a subchondral raft of 4.5-mm cancellous screws was used. A locking medial plate was slid through the medial parapatellar approach, and percutaneous locking screws were inserted to complete the fixation.
This article focuses on the treatment of femoral mid-distal segments using the distal femoral lock compression plate (LCP-DF) using the MIPO technique. Through the medial parapatellar approach, slight eversion of the patella and flexion of the knee exposes the distal articular surface, particularly of the medial femoral condyle, thereby enabling reduction and fixation of the articular fractures. Large pointed reduction forceps were useful to hold the medial and lateral femoral condyles together after reduction. A Kirschner wire was inserted into the medial condyle for temporary fixation of the articular surface fractures. The distal femoral fracture changed from C3 to A3.
For extraarticular fractures, a modified standard lateral approach was used. The implant was slipped into a submuscular tunnel along the lateral cortex of the femur. A minimum 7-hole–length coverage over the shaft fixation with five screws was optimum. The screw cannot be placed in the middle segment. Therefore, in this case, a 14-hole LCP-PLT was chosen. The distal part of the LCP-DF was aligned according to the anatomical reference with the distal femur, and the proximal part of the plate then ran along the femoral shaft. To obtain a closed reduction, traction was performed after temporary fixation of the femoral condyle with the distal part of the plate. Manual traction was applied to the ankle with a force vector that was directed posteriorly using the supracondylar pad as a fulcrum to help reduce the fracture and restore limb length and rotational and axial alignments. Fluoroscopic images were rechecked. Final fixation was achieved using locking screws at either end of the plate. A total of seven 5.0-mm locking screws were placed into the distal fragment and five screws were placed in the shaft fragment. This construct aimed to combine absolute stability with fixed angle stability and relative stability using bridging technology. After fixation, the stability of the knee joint should always be checked. Limb length, axes, and rotation were checked using clinical and radiological methods.
Bone defects were observed in the middle fragment. Bone grafting to correct the fragment loss was not performed, because the loss did not affect the length and alignment of the femur, and the entire construct had a stable and balanced fixation as previously described.
A final check of fracture reduction and fixation was performed using the image intensifier. Overall, the construct achieved a balanced and adequate fixation. After internal fixation, passive exercises were performed on the patient under anesthesia.
3.3. Outcomes and follow-up
Postoperative 3D CT and radiography confirmed that the intraarticular fractures underwent anatomic reduction, and the left femur line was restored, with internal fixation in a good position. However, there were three unreduced reverse fragments (1, 2 and 3) in the femoral mid-distal segment after plating (Fig. 3 a-e). On the first postoperative day, the patient began continuous passive range-of-motion (ROM) exercises under the guidance of an orthopedic surgeon. The patient was allowed to walk on crutches with toe-touch weight-bearing during the first 6 weeks. Because of the need for functional exercise, the unreduced reverse fragment (3) was removed through small incisions 1.5 month postoperatively. Depending on fracture consolidation visible on the radiographs 1.5 month, weight bearing is progressively increased to full weight bearing at 3 months. Radiographic examination at 3 months showed no displacement at the fracture end, and the fracture line was blurred by the formation of a large amount of callus. A further radiographic examination at 1 year showed good lower limb alignment and good plasticity of the bone structure. Final follow-up taken at 3 years showed good lower limb alignment and complete plasticity of the bone structure, by which time the patient showed good limb function (acceptable range of knee motion of 0°–100° was achieved). Although fractures of the middle and lower femur have healed, the bone strength is insufficient ; hence, implant removal will not be considered (Fig. 3 i-r).