When Conservative Treatment Fails For Posterior Tibial Tendon Dysfunction
After a 50-year-old patient is unresponsive to conservative treatment, this author presents a surgical approach to the condition and offers pearls on effective fixation.
An obese 50-year-old female presented with significant posterior tibial tendon dysfunction that was unresponsive to multiple conservative measures. A custom-fitted AFO provided some notable pain relief but the patient was unable to tolerate wearing the device secondary to irritation. Despite numerous modifications to the brace, the patient eventually elected to proceed with surgery.
Her history and physical exam revealed that she had well controlled type 2 diabetes and hypertension. She was a non-smoker. As a factory worker, she stood approximately eight to 10 hours per day. She was unmarried and did not have family in the vicinity to help her during the healing period.
The patient was 5’3” and weighed 255 pounds. Her neurovascular exam revealed no abnormalities. The musculoskeletal examination revealed a unilateral, flexible flatfoot with weightbearing. She had an inability to raise her heel on the affected side and a pronounced equinus, primarily with her knee extended.
Key Insights On Procedure Selection
I performed a gastrocnemius recession, talonavicular arthrodesis and a medial calcaneal displacement osteotomy. Despite recommendations for strict non-weightbearing, the patient ambulated on a regular basis, even when she used a below-knee cast.
There are multiple, well-developed reconstructive procedures to address posterior tibial tendon dysfunction. These procedures include tendon augmentation/transfer, osteotomies and single or multi-joint fusions.
As with most surgeons, my surgical approach has changed over time. Given the patient's obesity, I think a triple arthrodesis would have been a very acceptable procedure for this particular patient. However, given the higher likelihood of complications with a triple arthrodesis, I elected to perform a single joint fusion as I have not had good results in many patients having an isolated talnavicular fusion procedure. In those patients, there still seems to be a valgus “attempt” of the heel with weightbearing and continued pain. After performing a secondary medial calcaneal displacement osteotomy for those patients with continued pain, they had resolution of their symptoms. Accordingly, it is rare for me to perform a talonavicular fusion now without a concurrent medial calcaneal displacement osteotomy.
Pertinent Pearls On Fixation
There are numerous choices for fixation of an arthrodesis. When it came to this particular patient, I was concerned about her ability — and choice — to be non-weightbearing. Originally, I considered a circular external fixator to allow at least some greater protection with weightbearing. I decided against this because even with an in-patient stay and possibly an extended rehabilitation stay afterward, I felt the possibility of complications outweighed the benefits. In the end, I opted for an alternative form of fixation that I felt provided greater rigidity and compression in both the osteotomy and arthrodesis sites. I chose to use the IOFix device (Extremity Medical). Although there are several good forms of fixation, this particular device has worked well for me in cases in which compression and stability may be tested much earlier than they should.
Although I typically do not advise the patient to even attempt partial weightbearing until six to eight weeks postoperatively, I have become more comfortable with using this particular device in cases that have a slightly higher risk of failure than others.
In this case, she was essentially fully weightbearing with at least the additional protection of a cast immediately upon her discharge from the hospital. The calcaneal osteotomy was much more likely to heal appropriately even without strict non-weightbearing but the talonavicular arthrodesis site was, in my experience, much more likely to progress to a delayed or non-union.
In the end, despite the patient's obesity and non-adherence, she healed exceptionally well and does not require the use of any type of brace. She does still use a custom orthotic regularly.