Proximal tibiofibular joint instability
A severe ankle twist may transmit the force right to the top of the fibula, and stretch the ligaments connecting the fibula to the tibia. The fibula may periodically sublux (slip partially out of joint) at the lower side of the knee. High force injuries, such as road traffic accidents, may disrupt the joint to the extent that the top of the fibula can actually rotate outwards during a deep squat, and the peroneal nerve may be irritated and cause pain in this region.
Dislocation of the proximal tibiofibular joint. Milankov M, Kecojević V, Gvozdenović N and Obradović M. Med Pregl. 2013 Sep-Oct;66(9-10):387-91.
Lateral ankle fracture with missed proximal tibiofibular joint instability (Maisonneuve injury).. Hirschmann MT, Mauch C, Mueller C, Mueller W and Friederich NF. Knee Surg Sports Traumatol Arthrosc. 2008 Oct;16(10):952-6. doi: 10.1007/s00167-008-0597-8. Epub 2008 Aug 19.