The forgotten joint: quantifying the anatomy of the proximal tibiofibular joint

Limited objective data exist detailing the quantitative anatomy of the individual bundles of the proximal tibiofibular joint and their relation to surgically pertinent osseous landmarks. The purpose of this study was to qualitatively and quantitatively describe the ligamentous anatomy of the proximal tibiofibular joint and its relation to relevant bony landmarks.

Ten non-paired, fresh-frozen cadaveric knee specimens were dissected to identify the proximal tibiofibular joint ligament bundles. Pertinent bony landmarks were identified and served as reference points for the tibial and fibular attachments for each bundle. Ligament bundle footprints, lengths and orientations were measured using a 3D coordinate measuring device.

Up to four bundles were identified anteriorly and up to three bundles posteriorly. The inferior bundle was identified anteriorly and posteriorly in 60% and 20% of the cases, respectively. For the anterior complex, the centres of the tibial attachments were a mean distance of 12.5 mm (95% CI [10.7, 14.3]) and 25.3 mm (95% CI [21.6, 29.0]) from the tibial plateau for the superior and inferior bundles, respectively. The centres of the fibular attachments were 11.3 mm (95% CI [7.4, 15.1]) and 27.0 mm (95% CI [24.0, 30.0]) from the apex of the fibular styloid for the superior and inferior bundles, respectively. For the bundles of the posterior complex, the centres of the tibial attachments were 13.4 mm (95% CI [11.6, 15.2]) and 38.8 mm (95% CI [31.0, 46.6]) distal to the tibial plateau for the superior and inferior bundles, respectively, and the centres of the fibular attachments were 8.0 mm (95% CI [5.8, 10.1]) and 29.3 mm (95% CI [25.5, 33.1]) from the apex of the fibular styloid for the superior and inferior bundles, respectively. In the coronal plane, the mean 2D angle between the medial to lateral knee joint axis and the axis passing through the centre of the proximal tibiofibular joint and the centre of the tibial plateau was 16.9° (95% CI [12.8, 21.0]).

The ligament bundles of the proximal tibiofibular joint were reproducibly identified between specimens in relation to surrounding bony landmarks. Up to four bundles were identified in the anterior ligament complex and up to three in the posterior complex. Variation in bundle orientation and footprint size was observed. Based on these findings, an anatomic reconstruction can be performed using surrounding reliable landmarks.