Range of Motion Protocol for Tibial Plateau Fractures in Hinged Knee Brace
Yes, allowing flexion to 60 degrees in a hinged knee brace while nonweightbearing is generally appropriate for most tibial plateau fractures, though the specific fracture pattern and stability must guide this decision. 1
Evidence-Based Rationale
The British Journal of Sports Medicine guidelines explicitly recommend early knee mobilization following surgical fixation of tibial plateau fractures to increase joint range of motion, reduce knee pain, and prevent extension deficits and other soft tissue complications. 1 This supports progressive range of motion even in the early postoperative period.
However, a critical caveat exists: biomechanical cadaver studies demonstrate that posteromedial tibial plateau fragments can displace even during nonweightbearing range of motion exercises, with displacement occurring at flexion angles as low as 15 degrees and progressively worsening up to 90 degrees. 2 This displacement occurred with axial compression forces combined with internal rotation torque and varus moments that naturally occur during knee flexion. 2
Fracture Pattern-Specific Considerations
Stable Fracture Patterns
- Lateral plateau wedge fractures and minimally displaced compression fractures typically tolerate early range of motion well 3
- Cast-brace treatment studies from the 1980s demonstrated successful outcomes with early flexion exercises for these patterns 3
- One case report described unrestricted range of motion immediately postoperatively for a lateral plateau fracture with good outcomes 4
Unstable Fracture Patterns Requiring Caution
- Posteromedial fragments are particularly vulnerable to displacement during flexion, even when nonweightbearing 2
- Bicondylar and comminuted fractures carry higher risk of complications and may require more conservative motion protocols 5
- Fragments as small as 10mm showed displacement starting at 15 degrees of flexion in biomechanical testing 2
Recommended Protocol
For most surgically stabilized tibial plateau fractures:
- Flexion to 60 degrees while nonweightbearing is reasonable if adequate surgical fixation was achieved 1
- Closed kinetic chain exercises should be prioritized in the first 4 weeks 1
- The hinged brace provides stability during this early mobilization phase 6
Prerequisites before allowing 60 degrees flexion:
- Adequate surgical fixation confirmed on postoperative radiographs 5
- Absence of significant posteromedial fragment involvement (or confirmed stable fixation of such fragments) 2
- Pain controlled to manageable levels 1
- No evidence of fixation failure on initial postoperative imaging 7
Critical Pitfalls to Avoid
Do not rely solely on nonweightbearing status to protect the fracture. The biomechanical evidence clearly shows that knee flexion itself generates forces that can displace fracture fragments, independent of weight bearing. 2 This is particularly true for posteromedial fragments where displacement occurred at every flexion angle tested, ranging from 1.7mm at 15 degrees to 10.2mm at 90 degrees. 2
Avoid prolonged immobilization beyond what is necessary. Extended bracing provides no additional benefit and may impede rehabilitation progress, leading to muscle atrophy and joint stiffness. 1 The goal is early mobilization balanced against fracture stability.
Do not use time-based criteria alone. Progression should be based on functional and clinical assessment rather than arbitrary timelines. 1 This includes evaluating quadriceps control, knee stability, and pain levels. 1
When to Restrict Motion Below 60 Degrees
Consider limiting flexion to less than 60 degrees if:
- Posteromedial fragment is present and fixation stability is questionable 2
- Significant comminution exists with concern for articular collapse 5
- Associated ligamentous injuries compromise knee stability 1
- Poor bone quality or osteoporosis raises concern for fixation failure 1
- Early postoperative radiographs show any loss of reduction 7
In these scenarios, start with more restricted motion (0-30 degrees) and advance based on serial radiographic confirmation of maintained reduction. 2