Pain and Swelling in the Upper Fibula Near the Knee
Begin with plain radiographs of the entire leg to identify fracture, tibiofibular synostosis, or other bony pathology, as these are the most common structural causes of proximal fibular pain and swelling. 1
Initial Diagnostic Approach
Clinical Assessment
- Examine for point tenderness along the proximal fibula, particularly at the fibular head and neck, which may indicate stress fracture or synostosis 2
- Assess for recent trauma history, including ankle injuries or knee procedures, as proximal fibular fractures can occur after total knee arthroplasty or with valgus knee deformities 3
- Evaluate gait mechanics, particularly during midstance and preswing phases, as pain during these phases suggests tibiofibular synostosis or stress-related pathology 2
- Check for progressive symptoms developing months after an initial injury, which is characteristic of tibiofibular synostosis 2
Imaging Algorithm
- Order radiographs of the entire leg (not just the knee) as the initial imaging study, since proximal fibular pathology including synostosis and stress fractures require full-length views for diagnosis 2
- Consider MRI without contrast if radiographs are negative but clinical suspicion remains high, as MRI has 93-96% sensitivity for occult bone pathology and ligamentous injuries 4
- Bone scan may show increased tracer uptake in cases of tibiofibular synostosis or stress fracture when diagnosis is uncertain 2
Common Causes and Their Management
Tibiofibular Synostosis
This represents an abnormal bony bridge between the tibia and fibula that interferes with normal dynamic fibular function, subjecting the synostosis to repetitive stress and potential fatigue fracture 2.
Conservative management is recommended initially:
- Rest from aggravating activities 2
- NSAIDs for pain relief if no contraindications exist 5
- Activity modification to avoid vigorous exercise 2
Surgical excision should be reserved for:
- Athletically active patients with gradually progressing, disabling symptoms 2
- Cases where the synostosis has matured into cortical bone on radiographs 2
- Meticulous hemostasis and bone wax application during surgery may reduce recurrence risk 2
Stress Fracture of Proximal Fibula
This can occur in patients with abnormal knee mechanics, particularly valgus deformity, which places excessive stress on the fibula as a lateral strut 3.
Management approach:
- Immobilization for fracture healing 3
- Address underlying mechanical abnormalities (valgus deformity) to prevent progression 3
- Monitor for rapid deformity progression, as fibular disruption can accelerate valgus collapse 3
Syndesmotic Injury Extension
While syndesmotic injuries typically affect the distal tibiofibular joint, pain can radiate proximally along the fibula 6, 7.
Key diagnostic features:
- History of dorsiflexion and eversion with internal tibial rotation mechanism 4
- Perform crossed-leg test (pressure on medial knee producing pain) 4
- Pain along the interosseous membrane 7
Treatment based on grade:
- Grade 1 (stable): Immobilization for 1-3 weeks followed by gradual return to activity 6
- Grade 2 (questionable stability): Most favor surgical treatment, though conservative management possible if truly stable 6
- Grade 3 (unstable): Surgical reconstruction required 6
Pain Management Considerations
NSAIDs can be used cautiously for symptomatic relief 5:
- Effective for reducing pain and inflammation 4
- Avoid prolonged use as they may suppress natural healing processes 4
- Monitor for GI complications, particularly ulceration and bleeding 5
- Check hemoglobin if used long-term, as anemia occurs in 17-22% of patients on chronic NSAID therapy 5
Critical Pitfalls to Avoid
- Failing to image the entire leg when proximal fibular pain is present, as pathology may extend beyond the knee region 2
- Assuming all proximal fibular pain is muscular without excluding bony pathology through radiography 1
- Performing tumor biopsy principles if surgical excision is planned for synostosis, as misdiagnosis can occur 2
- Ignoring underlying mechanical abnormalities such as valgus knee deformity that predispose to fibular stress 3