The Tibialis Posterior Tendon Transfer for Foot Drop procedure is a surgical solution for patients suffering from foot drop, a condition where there is a loss of dorsiflexion, leading to difficulty in lifting the foot during walking. This condition can occur due to several reasons, including nerve injuries (such as peroneal nerve damage), neurological disorders, and trauma. Foot drop can severely affect gait, leading to high stepping, foot slapping, and difficulty in clearing the foot during the swing phase of walking. This article provides a detailed overview of the procedure, its indications, planning, surgical steps, and post-operative recovery.
Indications for Tibialis Posterior Tendon Transfer
The procedure is primarily indicated for patients who have foot drop due to:
- Common peroneal or deep peroneal nerve injury that has not recovered, whether from trauma or other causes.
- Compartment syndrome where there is loss of anterior compartment muscle function, but the deep posterior compartment muscles remain strong.
- Neuromuscular conditions that cause isolated weakness of ankle dorsiflexion.
Historically, this procedure was used for treating foot drop caused by leprosy, but it has evolved to address foot drop from other causes as well. A common assessment involves observing the patient’s walking pattern, including the absence of heel strike and foot slap, as well as difficulty in clearing the foot during the swing phase of walking. This results in a high-stepping gait that can be unattractive and functionally limiting.
Preoperative Planning and Workup
The success of the procedure heavily depends on thorough preoperative evaluation:
Clinical examination: This includes testing for high-stepping gait, foot slap, and the absence of active dorsiflexion.
Muscle strength: The strength of the tibialis posterior muscle (the tendon used for the transfer) is evaluated. If this muscle is not strong enough, other muscles like the flexor digitorum longus may be considered for supplementation.
Passive range of motion: It is crucial to assess whether the ankle can be dorsiflexed to at least 15 degrees. If not, additional procedures may be required to restore this motion.
Imaging studies: X-rays are taken to rule out any co-existing ankle arthritis or other conditions that may suggest alternative treatments like ankle fusion.
The Surgical Procedure
The tibialis posterior tendon transfer is performed through several carefully planned incisions around the ankle and foot:
Incisions: Typically, three incisions are made: one near the navicular (for tendon harvesting), one on the medial leg near the medial malleolus (to access the tibialis posterior tendon), and one on the dorsum of the foot (to route the tendon to the target insertion site).
Harvesting the tendon: The tibialis posterior tendon is carefully released from its insertion on the navicular and prepared for transfer.
Routing the tendon: The tendon is passed through the interosseous membrane (a fibrous structure between the tibia and fibula) to reach the foot. During this step, great care is taken to avoid damaging nerves and blood vessels in the area, as these structures are crucial for proper foot function.
Anchoring the tendon: Once the tendon reaches the foot, it is anchored to the target bone or tendons using a fixation system. This ensures the tendon can provide the necessary dorsiflexion to correct the foot drop.
Postoperative Plan and Recovery
The recovery process focuses on reducing postoperative swelling and ensuring the proper function of the tendon:
Initial care: After the surgery, the patient is immobilized in a cast to keep the foot in dorsiflexion. This is important to allow the tendon to heal in the proper position.
Physiotherapy: After about six weeks, rehabilitation begins to re-educate the tibialis posterior tendon to activate and support dorsiflexion.
Follow-up care: Patients are regularly assessed to ensure the transfer is functioning as intended. This includes evaluating the patient’s ability to achieve a heel-to-toe gait and their range of motion in the ankle.
Risks and Complications
As with any surgical procedure, there are risks associated with tibialis posterior tendon transfer:
General risks: These include infection, scarring, nerve injury, and blood clots.
Specific risks: These include failure of the tendon transfer, further surgery, or complications like compartment syndrome.
Postoperative rehabilitation: The patient must avoid passive plantarflexion during physiotherapy to prevent detachment or stretching of the tendon.
Conclusion
In conclusion, tibialis posterior tendon transfer is a highly effective treatment for foot drop when nerve recovery is not expected. It offers patients the potential to regain functional use of their foot, improving their gait and overall mobility
