Articular Surfaces
- Fibular head (flat to slightly convex): A small, oval facet on the posterolateral fibular head
- Lateral tibial condyle (flat to slightly concave): A matching facet on the posterolateral aspect of the lateral tibial condyle
Movements and ROM
| Movement |
Description |
Mechanism |
| Anterior glide |
Fibular head glides anteriorly |
Occurs during ankle dorsiflexion and knee extension |
| Posterior glide |
Fibular head glides posteriorly |
Occurs during ankle plantarflexion and knee flexion |
| Superior glide |
Minimal superior movement |
During weight-bearing ankle dorsiflexion |
| Rotation |
Slight fibular rotation |
During pronation/supination of the foot |
Fibular motion is linked to the ankle. During ankle dorsiflexion, the wider anterior talus wedges between the malleoli, pushing the fibula laterally and superiorly. This force is transmitted up the fibular shaft to the proximal tibiofibular joint, which must glide to accommodate it. A hypomobile proximal tibiofibular joint can therefore limit ankle dorsiflexion.
Capsular Pattern
Pain with stress to the joint, particularly during ankle dorsiflexion
No clearly defined proportional pattern. Restriction presents as decreased fibular head mobility on accessory motion testing.
Resting Position
- 25° knee flexion, 10° ankle plantarflexion
Close-Packed Position
- Not clearly defined — some sources describe full ankle dorsiflexion (fibula maximally displaced)
End-Feels
| Movement |
Normal End-Feel |
Type |
| AP fibular head glide |
Capsular (firm) |
Joint capsule and tibiofibular ligaments |
Ligaments
Anterior Tibiofibular Ligament (Proximal)
- Attachments: Anterior fibular head ��� anterolateral tibial condyle
- Function: Resists posterior displacement of the fibular head
Posterior Tibiofibular Ligament (Proximal)
- Attachments: Posterior fibular head → posterolateral tibial condyle
- Function: Resists anterior displacement of the fibular head. Stronger than the anterior ligament.
Mobilization Techniques
Hands-on instruction is required. The descriptions below provide clinical reference detail for understanding and supervised practice. They are not a substitute for instructor-led technique training. Correct hand placement, force dosage, and tissue response interpretation require hands-on coaching and feedback.
General Contraindications
- Absolute: Fibular head fracture, proximal tibiofibular dislocation, common peroneal nerve injury (the nerve wraps around the fibular neck — manipulation near it risks nerve damage)
- Relative: LCL injury (the LCL inserts on the fibular head), posterolateral corner injury
Important Anatomical Caution
The
common peroneal (fibular) nerve wraps around the fibular neck immediately distal to the fibular head. This is the most commonly injured nerve in the lower extremity. Any mobilization of the proximal tibiofibular joint must avoid compressing this nerve. If the patient reports tingling, numbness, or electric sensations radiating down the lateral leg and foot during mobilization, stop immediately.
Anterior-Posterior Fibular Head Glide
Purpose: Restores fibular head mobility. Anterior glide is the most commonly needed direction (the fibular head must glide anteriorly for ankle dorsiflexion).
Patient position:
- Supine or side-lying with the knee flexed to approximately 25° (resting position)
- The foot should be relaxed
Hand placement:
- Stabilizing hand: Cups the medial tibial condyle, stabilizing the tibia
- Mobilizing hand: Thumb and index finger grip the fibular head. For anterior glide, the thumb contacts the posterior fibular head and pushes anteriorly. For posterior glide, the fingers contact the anterior fibular head and push posteriorly.
Technique execution:
- Apply a slow, oscillatory force directed anteriorly (for anterior glide) or posteriorly (for posterior glide)
- Grade I–II: Gentle oscillations for assessment and pain modulation
- Grade III: Oscillations into end-range for mobility restoration
- Duration: 20–30 seconds per direction, 2–3 sets
Indications:
- Decreased fibular head mobility on accessory motion testing (compare bilaterally)
- Limited ankle dorsiflexion that persists after addressing the talocrural joint and gastrocnemius/soleus
- Lateral knee pain of unclear origin (proximal tibiofibular dysfunction mimics LCL or ITB pathology)
Technique notes:
- Common peroneal nerve caution: The mobilizing contact must be on the fibular head itself, not the fibular neck below. Avoid sustained pressure on the posterolateral fibular neck where the nerve wraps around.
- Reassessment: Re-test fibular head mobility and ankle dorsiflexion. If dorsiflexion improves, the proximal tibiofibular joint was the limiting factor.
Superior-Inferior Fibular Head Glide
Purpose: Restores vertical fibular mobility. An inferior glide is typically needed when the fibular head is held in a superior position (common with biceps femoris tightness, which attaches to the fibular head).
Patient position: Same as above.
Hand placement:
- Grip the fibular head with thumb and index finger. For inferior glide, direct force inferiorly (toward the feet). For superior glide, direct force superiorly.
Technique execution:
- Gentle oscillatory force in the desired direction
- Duration: 20–30 seconds, 2–3 sets
Indications:
- Superior fibular head position from biceps femoris hypertonicity
- Adjunct to AP mobilization for comprehensive fibular head restoration
Muscles Crossing This Joint
Conditions Affecting This Joint
- Proximal tibiofibular hypomobility — restricts ankle dorsiflexion and produces lateral knee pain; commonly overlooked in both knee and ankle assessments
- Proximal tibiofibular dislocation — rare; anterolateral dislocation is most common; presents as a visible prominence on the lateral knee
- Common peroneal nerve injury — the nerve wraps around the fibular neck and is vulnerable to compression (leg crossing, tight casts, fibular head fracture); produces foot drop (dorsiflexion weakness) and lateral leg numbness
Clinical Notes
- The "missed link" in ankle dorsiflexion restriction. When ankle dorsiflexion is limited and talocrural and soft tissue restrictions have been addressed, assess the proximal tibiofibular joint. Fibular head mobility is required for the mortise to widen during dorsiflexion. This is one of the most commonly missed findings in ankle rehabilitation.
- Lateral knee pain differential. Proximal tibiofibular dysfunction presents with lateral knee pain that can mimic LCL sprain, ITB syndrome, or lateral meniscal pathology. Fibular head tenderness and decreased AP glide on accessory testing distinguish it. Always palpate the fibular head and test its mobility in lateral knee pain presentations.
- The common peroneal nerve is extremely vulnerable. Habitual leg crossing, tight casts, and prolonged lateral recumbency (lateral decubitus position during surgery) can compress the nerve against the fibular neck. Always ask about numbness on the lateral leg and dorsal foot and test ankle dorsiflexion strength when assessing this joint.
Key Takeaways
- The proximal tibiofibular joint is the "missed link" in ankle dorsiflexion restriction — always assess fibular head mobility when dorsiflexion limitation persists after addressing the ankle.
- The common peroneal nerve wraps around the fibular neck — avoid compressing it during mobilization; stop if the patient reports tingling down the lateral leg.
- Proximal tibiofibular dysfunction can mimic LCL, ITB, or lateral meniscal pathology — palpate the fibular head and test AP glide in all lateral knee pain presentations.
