Posterolateral Approach to Fibula
Posterolateral approach to fibula can be used to access the whole of the fibula from head to the lateral malleolus. But in practice, it is most commonly used in upper three-fourths of the fibula
It is used in open reduction and internal fixation of fibula fractures, resection of fibula or excision of fibular bone lesions.
It uses the internervous plane between peroneal muscles [superficial peroneal nerve and muscles of the posterior compartment [tibial nerve].
An internervous plane is one where the muscular supply on either side of the plane is by different muscles.
The patient is kept in a supine position with a bump under the affected limb. Some surgeons prefer the lateral approach. The fibula can be approached in a prone position also in cases where a second surgery is being done in the prone position.
Incise the skin along the posterior margin of the fibula. The extent of the lesion would vary depending on the area of interest. For exposing complete upper three-fourths of the fibula, begin incision about 12 cm proximal to the lateral malleolus and incise the skin proximally along the posterior margin of the fibula to the posterior margin of the head of the bone. The incision can be continued farther proximally for 5-10 cm along the posterior aspect of the biceps femoris tendon.
Beginning proximally, incise the fascia taking great care not to damage the common peroneal nerve and divide the superficial and deep fasciae.
Identify the posterior border of the biceps femoris tendon and its insertion into the head of the fibula. Identify and isolate the common peroneal nerve as it courses behind the biceps femoris tendon.
Mobilize the common peroneal nerve by cutting the fibers of the peroneus longus.
Pointing the knife blade proximally and anteriorly, detach the part of the peroneus longus muscle that arises from the lateral surface of the head of the fibula proximal to the common peroneal nerve. Retract the nerve over the head of the fibula.
Develop a plane between the soleus muscle posteriorly and the peroneal muscles anteriorly, and deepen the dissection along the plane to the fibula.
Expose the bone by retracting the peroneal muscles anteriorly and incising the periosteum.
Avoid injury to the branches of the deep peroneal nerve that lie on their deep surfaces and are in close contact with the neck of the fibula and proximal shaft.
Make a longitudinal incision in the periosteum of the fibula and strip the muscles that originate on the fibula to expose the bone.
Dangers and Risks
- Injury to the common peroneal nerve. This can be avoided by isolating the nerve proximally.
- The superficial peroneal nerve is susceptible to injury at the junction of a middle and distal third of leg and injury this nerve may cause numbness on the dorsum of the foot.
Approach to Distal Fibula
The distal fourth of the fibula is subcutaneous on its lateral aspect and may be exposed by a longitudinal lateral incision through the skin, fascia, and periosteum.
The longitudinal lateral incision is the standard approach for most lateral malleolus fractures.
For plating, the incision should be placed either slightly anteriorly or posteriorly so as to avoid plate directly underneath the incision.
For posterior plating, the incision is placed slightly posteriorly, so that the soft-tissue dissection can be minimized.
Similarly, for anterior access, place the incision slightly anteriorly.
- Incision of the desired length in line with the fibula, starting proximally. The length of the incision would be determined by the level of fracture or area of interest.
- Continue distally a further 2 cm, curving slightly, anteriorly in relation to the tip of the lateral malleolus. This curving increases exposure and releases tension.
- The dissection plane is between the peroneus tertius anteriorly. Damaged soft tissue needs to be handled carefully and excessive traction is avoided. The superficial peroneal nerve lies very closely anteriorly, especially in the proximal part of the incision whereas the short saphenous vein and the sural nerve should be protected posteriorly
Deep surgical dissection
- Strip the periosteum to expose the bone. Do not be liberal with periosteal stripping as it poses a risk of devascularization.