Victor J Quijano Jr. DPM, PhD, FACLES, FAPWH, FACFAS
Since it was first described in the medical literature in 1908, few reports have been published on ossification of the tendon-Achilles (OTA) (1). Patients may have a chief concern of a painful palpable mass on the posterior inferior aspect of the Achilles tendon. However, patients may be asymptomatic, and the mass may be an incidental findings on radiographic examination. Some patients may report a known injury.
OTA is characterized by the presence of an ossified mass contained in the fibrocartilaginous substance of the tendon (1-3). Ossification of more than 50% is unusual, and occurs twice as frequently in males, with no age predilection (2-4). While the exact etiology of OAT has remained elusive, the literature to date suggests that it may be multi-factorial (5). One published case study in 2013, reports 3 siblings with OAT. with no known traumatic factors, suggesting a possible genetic component (6).
Some patients that have ossification of Achilles tendon, may have a subsequent fracture of the tendon ossification, with a subsequent partial or full tear of the Achilles tendon (7-11). Surgical intervention of such an injury can be accomplished through a variety of methods, such as flaps and tendon transfers (7-11). In this case study, the Wright Medical Graft Jacket®, both non-meshed and flowable, was utilized to repair a large deficit in the patients Achilles tendon, once the fractured ossification was removed.
A 56 year old, non-insulin dependent diabetic male presented to the office for pain in his posterior ankle. His additionally history contained hypertension, hypercholesterolemia, and cerebral palsy affecting his left side, with associated weakness. The patient stated that he understood that with his cerebral palsy he was somewhat limited in his activities, but since he felt a pain in the back of his ankle while playing basketball several months ago, he could not participate in sports anymore. The patient stated that after the injury day, he had mild edema and pain, but could still walk. Furthermore, the patient related that he wanted to get back to work, but with his skill set, he would be on his feet for long periods of time. He had not sought any medical treatment at the time of his initial injury.
Physical examination resulted in vascular status being significantly diminished bilaterally. Neurological status evaluation concluded that gross epicritic sensation was also diminished, as well as. vibratory sensation utilizing a 128 mHz tuning fork at the level of the first metatarsal-phalangeal joint. Onychomycosis and atrophic skin changes were noted bilaterally. Orthopedic exam revealed bilateral pes valgus, with mild hallux-abductovalgus and hammertoes at level DIPJ/PIPJ digits 2-5. Manual muscle test (MMT) of anterior and lateral groups was 5/5. Evaluating the posterior musculature revealed 5/5 MMT on the right, 4/5 MMT on the left. Additionally, a hard palpable mass was noted on the left side.
Radiographic evaluation of the ankle, a large osseous mass, in 5 pieces, contained within the Achilles tendon was identified (Fig 1). The dimensions identified were a 105.41 mm long radiopaque mass, 9.38 mm superior to the calcaneus. The widest piece dimension was 11.21 mm anterior-posterior and 11.73 mm medial to lateral. A subsequent MRI (Fig 2 A-C) revealed that the largest osseous portion comprised 53.8 % of the Achilles tendon, more medially than laterally. No tears in the tendon were noted. There was an increased signal in T2 in the tibio-talar joint, representing an ankle effusion.
Options were reviewed with the patient. These included conservative measures, such as immobilization and physical therapy. Surgical intervention was discussed with patient, which involved removal of the osseous mass and utilizing the Wright Medical Graft Jacket® product. The patient opted for surgical intervention.
Patient was brought into the operating room and was placed in a prone position. Once the patient was placed in a safe position, a left common peroneal/popliteal block was administered using 20 ml of a 50;50 mixture of 2% lidocaine:0.5% bupivacaine, after bi-plane aspiration was performed. A well-padded thigh tourniquet was placed and the left lower extremity was scrubbed, prepped and draped in a sterile fashion. An incision was then placed over the osseous mass slightly medial to the posterior calf midline. The incision was deepened through the sub-cutaneous tissue and the Achilles paratenon was incised, allowing access to the osseous mass. Through sharp and blunt dissection, the osseous mass was removed in toto, as demonstrated with intraoperative fluroscopy (fig 3). All 5 pieces were, what appeared, to be fibrosed as one mass. The lateral 40% of the Achilles remained intact. Once the osseous mass was removed, a non-meshed Graft Jacket® was placed circumferentially around the tendon with 2-3 mm overlap on the intact normal tendon. The graft was then secured with 3.0 Vicryl® in a simple, interrupted fashion. Flowable Graft jacket® was then injected in the space between the tendon and the graft. In the span of the graft, the area was smoothed to insure no abnormal contour. Normal closure of the skin and sub-q tissues were then performed with Vicryl®. A cast with foot 90 degrees to the leg was then applied.
The patient was kept in a below knee cast with foot 90 degrees to leg for 6 weeks, with interval changes every 2 weeks. At the conclusion of 6 week span, patient was placed partial weight bearing in a lower leg walker. The patient at this time had active plantar-flexory power of the Achilles tendon with minimal pain. After a total of 8 weeks post-operative time had elapsed, patient was allowed to fully weight bear in a lower leg walker for 3 weeks. At the end of the three weeks he was allowed to weight-bear in a high top shoe to toleration with use of a cane. Within 14 weeks post-operatively, patient was ambulating in a normal shoe without incident. Palpation of his left Achilles tendon reveals no deficits, paralleling radiographic evidence of no osseous bodies remaining. Patients MMT of the Achilles was 4/5. 6 months post-operatively, with one month of physical therapy, the patient was actively initiating in light sports and had secured a job.
The diagnosis of OAT is a clinical entity, however rare. While the exact etiology of OAT remains elusive, a genetic component may exist. Patients exhibiting an OAT diagnosis, may or may not present with pain. Simple radiographic evaluation can be used to show the size of the osseous mass. However, an MRI, or ultrasound, should be utilized to determine how much of the Achilles girth is osseous. Surgical intervention of OAT can involve flaps and tendon transfers to repair the tendon once the mass is removed.. This case study discusses the use of non-meshed and flowable Graft Jacket to successfully repair the Achilles tendon after removal of a large osseous mass.
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Fig 1. Radiographic analysis of patient’s left ankle demonstrating large osseous mass in Achilles tendon.
Figure 2. MRI left ankle demonstrating osseous mass. A. T1 axial, B. T1 coronal, and C. T1 sagittal.
Fig 3. Intraoperative radiographs demonstrating osseous mass intact A. and when removed B.