Essential Insights On Treating Retrocalcaneal Exostosis

Michael S. Downey, DPM, FACFAS­­

Step-By-Step Pearls On A Modified Approach To The Fowler-Philip Technique

   The literature has described many surgical approaches to the retrocalcaneal exostosis and spur over the years. I have been performing a modification of the Fowler-Philip approach to the retrocalcaneal exostosis and spur since 1987. Fowler and Philip first described an inverted “Y” incision through the tendon in 1945.5 They described their rationale for this approach based upon their observations of the anatomic insertion of the Achilles tendon:

    “The central portion of the tendon is inserted into the middle area on the posterior surface of the bone while the lateral parts of the tendon sweep on to the medial and lateral surfaces of the os calcis so … the central part of the tendon can be divided transversely, avoiding the lateral expansions, and when the central portion is re-sutured, there is little risk of permanently weakening the tendo-Achilles.”

   I advocate either an inverted “V” or “Y” approach through the Achilles tendon in this fashion. This approach allows removal of any retrocalcaneal exostosis or insertional spur, and any intratendinous calcification present.

   The surgeon can best perform the technique for the modified Fowler-Philip approach with the patient in a prone position. Typically, one would utilize general inhalation or spinal anesthesia with a mid-thigh pneumatic tourniquet. If desired or medically necessary, one can perform the procedure with

   the patient in the lateral or supine position, using local anesthesia with or without a tourniquet.

   The surgical approach is usually through a midline, longitudinal incision. This approach is different from what Fowler and Philip advocated. Fowler and Philip utilized a curved transverse incision with the convexity of the incision directed upward.5 I have not utilized this approach as the longitudinal approach provides better exposure of the Achilles tendon.

   Carry dissection bluntly deep through the subcutaneous tissue until visualizing the deep fascia. Take care to avoid the sural nerve and the lesser saphenous vein during this dissection. With the subcutaneous tissues retracted, make a single inverted V or Y incision through the deep fascia, paratenon and tendon. Center the apex of the V at the dorsal aspect of the spur, which one can easily palpate through the tendon. Then carry the arms of the V or Y medially and laterally to the distal medial and distal lateral extents of the exostosis or spur. The arms are typically 1 to 1.5 cm in length.

   If no intratendinous calcification or dystrophic tendon is present, the inverted V approach is usually sufficient. If calcification or dystrophic tendon is present, convert the inverted V into an inverted Y and split the tendon more proximally in its midline to excise the calcification and/or diseased tendon fibers.

   After incising the tendon, reflect the V flap distally, taking care to preserve its distal attachment. This dissection needs to proceed carefully to detach all soft tissue from bone, similar in fashion to the detachment of the capsule from the medial eminence of the first metatarsal head during bunion correction surgery. Then expose the retrocalcaneal spur, step and/or exostosis. Resect the exostosis and spur with osteotomes or power instrumentation. I generally prefer using a curved osteotome to remove the bulk of the bone and subsequently use a power reciprocating rasp or hand rasp to contour the remaining bone.

   After removing an appropriate amount of bone, reanchor the tendon to bone with suture anchors. This is another modification of the Fowler and Philip procedure as they did not discuss this reattachment. I feel the reattachment strengthens the repair. The surgeon can accomplish the reattachment by suturing the tendon to bone with non-absorbable suture through drill holes or, more commonly, by using a suture anchor system to accomplish the tenodesis.

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