Injury to the proximal tibiofibular joint is rather rare, but it can be debilitating in patients who have symptoms. The usual mechanism is having a patient fall on a plantar-flexed ankle, with the stress being brought through the fibula, such that the proximal fibula will sublux out of place over the lateral aspect of the knee joint. In other circumstances, there may be a more obvious injury where one has a significant trauma or motor vehicle accident where the proximal tibiofibular joint is disrupted.
In most circumstances, it is the posterior proximal tibiofibular joint ligament which is disrupted. This results in the fibula rotating away from the tibia during deep squatting. This can result in a feeling of instability, a visible bony deformity, and concurrent irritation of the common peroneal nerve. This is because the common peroneal neve crosses the lateral aspect of the fibular neck within 2-3 cm of the lateral aspect of the fibular head.
The diagnosis of proximal tibiofibular joint instability is almost always based on a good clinical exam. In acute cases, it may be difficult to make the patient relax sufficiently to be able to examine for instability of the proximal tibiofibular joint, but usually having the knee flexed to 90 degrees and trying to perform an anterolateral subluxation maneuver of the proximal tibiofibular joint is sufficient to confirm this diagnosis. It is important to compare the injured side to the normal contralateral side because some of the patients may have some mild physiologic laxity of this joint. In more chronic cases, we have the patient squat down, which can often demonstrate that the proximal tibiofibular joint is being subluxed. Concurrent with this, we will perform a Tinel's test by percussing over the common peroneal nerve to confirm the presence of dysesthesias or "zingers," which translate down the leg.
The treatment of proximal tibiofibular joint instability usually depends upon whether it is an acute or chronic injury. In acute cases, we have found that immobilization is often very effective to allow the posterior proximal tibiofibular joint ligament tear to scar in sufficiently such that there is no instability. However, in chronic cases, immobilization would not be sufficient to achieve this goal. Thus, we have developed an anatomic proximal posterior tibiofibular joint reconstruction, which we have found to be very effective at restoring stability to this joint and not resulting in joint overconstraint. While others have often treated this joint by fusing it, we have reported that a proximal posterior tibiofibular joint ligament reconstruction is easily performed, does not overconstrain the joint and has a lesser chance of leading to ankle pathology further down the line. In addition, we commonly perform a common peroneal nerve neurolysis concurrent with the ligament reconstruction to release the scar tissue around the common peroneal nerve so that any further nerve irritation will not occur after surgery, due to postoperative swelling or scar tissue entrapment. Patients who undergo this reconstruction are kept on crutches for 6 weeks with no to minimal weightbearing, but are allowed full range of motion. We anticipate that our patients will return back to full activities about 4-5 months after surgery, following the rehabilitation program.
