Synovial Chondromatosis of the TMJ: Long-term Follow Up With Hemi-Joint Replacement

Problem: Synovial chondromatosis is a common pathology in many joints, including the hips, wrists, knees, elbows, and shoulders.  However, it rarely affects the temporomandibular joints.  Treatment has generally centered on complete synovectomy, and some recurrence has been reported.  We present long-term follow up of five cases treated definitively with synovectomy with concurrent hemi-joint replacement and abdominal fat grafting.

Materials and Methods: Mayo Clinic surgical and pathology records of cases for synovial chondromatosis from 1960 to 2011 were reviewed, yielding 14 cases affecting the TMJ and treated surgically at Mayo Clinic.  All cases were reviewed histopathologically to confirm diagnosis of synovial chondromatosis.  Patients were invited to return for follow up physical examination, CT scan, and questionnaire rating their experience on a scale of 1-10 (10 being best or no problems) in several domains:  Satisfaction, preoperative and postoperative pain, malocclusion, and range of motion.  Patients were queried as to perceived benefits and adverse effects of surgery as well as dietary changes.  This study was approved by the Mayo Clinic IRB.

Methods of data analysis: Descriptive statistics, i.e. mean and standard deviation or frequency, were computed for continuous variables or categorical variables, respectively.  Student’s t-test was utilized to compare means.  P-values less than 0.05 were considered statistically significant.

Results: 5 of 14 patients were able to return for long-term follow up.  In three of these five, this was the second operation for synovial chondromatosis, and the disease was incompletely removed in the prior operation (range 3 months to 4 years after initial procedure).  Each of these five patients was treated with synovectomy, arthrotomy, hemi-joint metal fossa replacement, and abdominal fat grafting to the affected joint.  Following surgery at Mayo Clinic by the senior author (EEK), there has been no recurrence of disease.  All five cases who returned, as well as CT data for four other cases treated in similar fashion, had evidence of significant osteoarthritis of the affected joint, concurrent with synovial chondromatosis.  Mean follow up was 6.75 years (range 5.9-9.7 years).  Mean age at surgery was 57 years.  Mean satisfaction was 8.75 out of 10.  Mean pain decreased from 7.5 preoperatively to 3.25 postoperatively (p=0.043).  All patients had transient postoperative malocclusion, with two requiring occlusal equilibration, and one patient seeing no resolution.  Range of motion did not change postoperatively.  1 patient required replacement of the hemi-joint prosthesis at 3 years.  One patient remains on a soft diet.

Conclusions: Findings of this study indicate that osteoarthritis may be a common disease process accompanying synovial chondromatosis of the temporomandibular joint.  It is unclear if this is causative or secondary to the disease process.  It is plausible that long-term irritation and inflammation in the setting of osteoarthritis may contribute to chondrometaplasia seen in synovial chondromatosis.  Similarly, trauma predisposes to both synovial chondromatosis and osteoarthritis of the TMJ.  All five of our subjects able to complete long-term follow up did very well with both synovectomy and treatment for osteoarthritis with metal fossa hemi-joint replacement and abdominal fat grafting, and when evidence of concurrent osteoarthritis is present, this is a reliable, definitive treatment modality.  A patient registry for this disease, as well as long-term follow up in large numbers would help elucidate both etiology and ideal treatment.

References 

Ardekian L, Faquin W, Troulis MJ, Kaban LB, August M. Synovial chondromatosis of the temporomandibular joint: report and analysis of eleven cases. J Oral Maxillofac Surg. 2005; 63:941-947.

Keller EE, Baltali E, Liang X, Zhao K, Huebner M, An KN. Temporomandibular custom hemijoint replacement prosthesis: prospective clinical and kinematic study. J Oral Maxillofac Surg. 2012; 70:276-288.