Synovial Chondromatosis of the Ankle

Synovial Chondromatosis of the Ankle Joint with Concomitant Flexor Hallucis Longus Tenosynovitis: A Case Report

As presented at the 2020 American College of Foot & Ankle Surgeons Annual Science Conference: Access here.

 Literature Review:

Synovial chondromatosis (SC) is an exceedingly rare joint pathology that is currently not well understood nor is the etiology. SC demonstrates distinct intra-articular and periarticular clusters of loose bodies which can be debilitating and significantly limit function. Clinically these patients may report clicking with joint pain and examination may reveal decreased range of motion with crepitation ultimately leading to osteoarthritis. This condition has a gender and demographic predilection for men within the 3rd - 5th decade of life.

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From a histological perspective, chondrocytes are seen undergoing metaplasia with varying degrees of atypia, which form cartilaginous nodules that can be appreciated grossly. Normal synovial tissue lacks these chondrocytes and hence the propensity to form these unusual cartilaginous bodies. Synovial analysis of the joint fluid reveals increased levels of chondrocalcin3, a protein identified in the 1980s, which is associated with the calcification of hyaline cartilage.

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Whether the approach open, arthroscopic, or combined, “surgical excision is needed” along with keen postoperative monitoring and close follow up as recurrence rates range from 3-23% after intervention.

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Case Report:

A 33 year old healthy male, active duty military service member, presented with an insidious onset of global right ankle joint pain and “popping” sensation over a 13 month period. Pain was rated 7/10, unalleviated, and exacerbated with plyometrics and impact training. Physical examination of the affected ankle demonstrated limited ROM and crepitation. Pre-operative radiographs and MRI revealed findings consistent with a diagnosis of SC, which was likely causing painful impingement and the notable flexor hallucis longus (FHL) tenosynovitis.

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Our patient elected to undergo surgery consisting of ankle arthroscopy, FHL tenosynovectomy, and loose body excision under general anesthesia with a regional block. First, a prone approach was utilized to create two peri-Achilles portals to access the FHL for debridement, explant any posterior loose bodies, and examine the posterior ankle joint margins. The patient position was then converted to supine to complete the loose body explantation and joint examination utilizing two standard anterior ankle arthroscopy portals. In total, 18 irregular, loose bodies (ranging from 0.4cm to 0.9cm in greatest dimension) were procured in formalin for analysis. Fluoroscopy was also utilized to ensure all radiodense bodies were removed. Manipulation of the ankle demonstrated free movement without crepitation.

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The intraoperative specimens were described by the pathologist as “multiple loose chondromas and osteochondromas” which confirmed our suspected SC diagnosis. The post surgical course was uneventful aside from an additional ipsilateral bunion surgery which was performed without any complications. Clinically the patient continued to demonstrate an uneventful linear progression of healing and return to full function over a 3 month period.     

At one year follow-up, the patient self-reported an excellent outcome without any recurrence of symptoms. Patient was not only capable of performing all ADLs but he was also able to complete his military Physical Readiness Test (PRT), including a timed 3 mile run, free of ankle pain. Repeat radiographs at 2, 4, and 12 months remained negative without any evidence of pathology or recurrence.

The surgical treatment for him was both curative, in that the patient's symptoms completely resolved, and functionally restorative, in that the patient was able to return to pre-injury activity levels while maintaining the high physical demands required of him for active military duty. 

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SC presents the foot and ankle surgeon a unique opportunity to not only restore function and improve quality of life but to prevent the undesirable outcomes associated with malignant progression. Practitioners must employ astute clinical gestalt, be quick to treat, and maintain close follow up when presented with SC cases. This patient having a combination of both intra- and extra-articular is exceedingly rare and a dual approach was necessitated. Using both the arthroscopic technique and open excision, all of the pathologic tissue was successfully removed and the source of impingement relieved. 

This case also came with added complexity considering the work related activity requirements and high demands placed upon the patient.  With an appropriate and reasonable length of time to heal post-procedure, along with a course of physical therapy, the patient was back to pre-pathology levels of functionality. 

After following the patient for over a year and monitoring progression without clinical or radiographic recurrence, we are pleased with the results.  The dual approach is not only a viable option but one that promises great outcomes.  This case is an attestation to the success that can be obtained utilizing this approach with a remarkable return to function for high demand patients.

Foot and Ankle Specialists