Tibiofibular Joints
Distal and Proximal Tibiofibular joints
Proximal TFJ
“The proximal (or superior) tibiofibular joint is a synovial joint located lateral to and immediately inferior to the knee. The joint is formed between the head of the fibula and the posterior-lateral aspect of the lateral condyle of the tibia (see Fig. 13.4). The joint surfaces are generally flat or slightly oval, covered by articular cartilage.175 Although the proximal tibiofibular joint is functionally independent of the knee (tibiofemoral) joint, anatomic connections exist between the capsules of the two joints”1
“A capsule strengthened by anterior and posterior ligaments and part of the tendon of the biceps femoris encloses the proximal tibiofibular joint (see Figs. 13.7 and 13.9). The tendon of the popliteus muscle provides additional stabilization as it crosses the joint posteriorly. When stressed by forces and torques generated while walking, 1–3 mm of anterior and posterior translations have been measured at this joint in cadaver specimens.162 The relative stability at this joint is needed to ensure that forces within the biceps femoris and lateral collateral ligament of the knee are transferred effectively from the fibula to the tibia. Although rare, acute dislocation of the proximal tibiofibular joint secondary to trauma has been described in the literature.”1
“The proximal, or superior, tibiofibular joint (see Fig. 20-1) is an almost plane joint with a slight convexity on the oval tibial facet and a slight concavity on the fibular head. The joint is located below the tibial plateau on the lateral condyle of the tibia. The tibial articulating facet faces laterally, posteriorly, and inferiorly. Although the joint is often described as a simple, synovial, modified ovoid, it functions as a modified sellar when combined with the distal, or inferior, tibiofibular joint (see Chapter 21)”2
“The joint capsule of the proximal tibiofibular joint complex is thicker anteriorly than posteriorly and, in 10% of the population, the synovium is continuous with that of the knee joint.1 The joint receives support from anterior and posterior ligaments and an interosseous membrane. The interosseous membrane attaches between the medial border of the fibula and the lateral border of the tibia, providing attachment to the deep anterior and posterior muscles of the leg. The majority of its fibers pass obliquely in an inferior and lateral direction.”2
“The proximal tibiofibular joint has more motion than its distal partner. The motion occurring at the proximal joint, consists of two glides, one in a superoinferior direction and the other in an anteroposterior direction.1 These motions are possible because of the orientation of the joint line, which also facilitates an osteokinematic spin of the fibula. The motion at this joint can be decreased by articular fibrosis or by softtissue restraints; the biceps femoris can pull or hold it posteriorly, whereas the tibialis anterior can pull or hold it anteriorly.”2
“Although the capsular pattern of restriction for this joint is unclear, it is probably indicated by pain during an isometric contraction of the biceps femoris with the knee at 90 degrees of flexion. The close-packed position for this joint, equally debatable, is probably weight-bearing (WB) ankle dorsiflexion.”2
“Both the tibia and the fibula are vulnerable to fracture at the lower third of their shaft. Anterior joint subluxations occur at this joint as a result of medial knee joint strain or an inversion sprain of the ankle. Posterior joint subluxation can occur as a result of a lateral knee joint strain, but this is often missed because of the more serious ligament damage to the knee.”2
Innervation
“The nerve supply to this joint is provided by the common fibular (peroneal) and recurrent articular nerves. The joint receives its blood supply from a perforating branch of the fibular (peroneal) artery and the anterior tibial artery.”2
Arthrokinematics
Dorsiflexion
According to Dutton, during DF the fibula glides superiorly at the proximal tibiofibular joint2
Distal tibiofibular joint
Arthrokinematics
Dorsiflexion
According to Dutton, during DF the tibia and fibula are thought to glide superiorly and separate slightly at the distal tibiofibular joint2. The amount of glide appears to be negligible, but some researchers theorize taht distal fibular dysfunction can lead to ankle inversion injuries2.
Joint Mobility Tests
Anterior & Posterior Assessments
- Patient positioned in supine
- Grip the tibia and fibula using one hand for each
- To assess the fibula, use one hand to prevent downward motion of the medial malleolus while the opposite hand glides the fibula anteriorly and posteriorly relative to the tibia2.
- To assess the tibial component, one hand will stabilize the fibula and lateral malleolus, while the opposite hand glides the tibia anteriorly and posteriorly relative to the fibula.
Superior & Inferior Assessments
In theory, one can assess the superior and inferior glide of the distal tibiofibular joint, but I do not currently have evidence for why this would be clinically relevant2
Functional movements
Dorsiflexion
During dorsiflexion, the ankle mortise must acommodate the talus as it wedges into the mortise. This requires an increase in the intermalleolar separation anteriorly and approximating the malleoli posteriorly. The distal tibiofibular joint achieves this through 30° of external/lateral rotation of the fibula on the tibia3.
During dorsiflexion, the talus rolls posteriorly and superiorly, thus the mortise must make room superiorly as well to prevent a premature stop. This is also achieved through tibiofibular movement, where the fibula superiorly translates on the tibia3.
| Distal Tibiofibular Joint | Proximal Tibiofibular Joint | |
|---|---|---|
| Dorsiflexion | Superior translation | Superior translation |
| Malleolar separation | Inferior Aspect Gapping | |
| External rotation | Posterior translation |
Plantarflexion
- Lateral malleolus moves inferiorly
- Lateral malleolus internally/medially rotates
| Distal Tibiofibular Joint | Proximal Tibiofibular Joint | |
|---|---|---|
| Plantarflexion | Inferior translation | Inferior translation |
| Malleolar approximation | Narrowing joint space | |
| Internal rotation | Anterior translation |