Chondrocalcinosis is a non-infectious, inflammatory arthropathy which is typically characterized by intra-articular deposition of calcium pyrophosphate dihydrate crystals. The occurrence of chondrocalcinosis in the temporomandibular joint is uncommon. This report describes the case of a 51-year-old female with periarticular chondrocalcinosis of the left temporomandibular joint. Disease progression and prolonged complaints of pain and limitation of mouth opening were indications for surgical treatment. The placement of an alloprosthesis of the left temporomandibular joint was performed simultaneously with a unilateral sagittal split ramus osteotomy of the right side of the mandible, to correct the class 2 malocclusion in this patient. In this case, an initial clinical diagnosis of synovial chondromatosis was made. Postoperative histopathological analysis changed the diagnosis to chondrocalcinosis. The deposition of calcium pyrophosphate dihydrate crystals was located in the outer joint capsule, which is an atypical localization of chondrocalcinosis of the temporomandibular joint.
The crystals were located in the outer joint capsule, which is an atypical localization of chondrocalcinosis.
The placement of an alloprosthesis was performed simultaneously with a unilateral sagittal split ramus osteotomy.
A definite diagnosis of chondrocalcinosis was only made after histopathological analysis.
Chondrocalcinosis or calcium pyrophosphate dihydrate (CPPD) deposition disease is a crystal arthropathy, also called pseudo-gout as the clinical presentation may mimic gout [ ]. This is a non-infectious, inflammatory disease which is characterized by the formation and the intra-articular or periarticular deposition of CPPD crystals [ ]. The most commonly affected joints are the knee and wrist [ ]. The occurrence of chondrocalcinosis in the temporomandibular joint (TMJ) is uncommon. Possible symptoms are the limitation of mouth opening, preauricular swelling and pain, arthropathy, otalgia and conductive hearing loss [ , ]. The clinical features of this pathology resemble the symptoms of several infectious, neoplastic and neurologic diseases. Therefore, chondrocalcinosis is a challenging diagnosis [ ]. Patients older than 60 years have an increased risk and there is no gender predilection [ ]. Diseases associated with chondrocalcinosis are hemochromatosis, hypophosphatemia, hyperparathyroidism, hypothyroidism, hypomagnesemia, hypercalcemia, trauma, renal genetic disorders and chronic kidney disease, frequently associated with a metabolic syndrome [ , ]. This case report to the best of the authors knowledge is the 45th reported case of chondrocalcinosis of the TMJ. The case is presented according to the CARE guidelines and discussed in the context of available literature on diagnosis and treatment of this pathology [ ].
A 51-year-old female was referred to the Department of Oral and Maxillofacial Surgery of the University Hospitals of Leuven, Belgium. The patient suffered from depression, for which she took selective serotonin reuptake inhibitors. She had no relevant medical or dental history or allergies. A timeline of her treatment is depicted in Fig. 1 .
The patient presented with left TMJ pain, a strong mandibular deviation to the left on mouth opening and progressive limitation of mouth opening (33 mm). History taking and clinical evidence identified years of severe bruxism. The complaints existed for over 10 years and were resistant to a conservative approach, including physical therapy, unlearning bruxism behavior and use of a splint. The patient had no other joint-related complaints. She had a class 2 malocclusion for which she never received orthodontic treatment.
Over the course of her symptoms, no imaging had been performed. Magnetic resonance imaging (MRI) was obtained only shortly before the patient was referred and showed a degenerated condyle with anterior osteophytosis and joint effusion in the left TMJ with a hypointense signal anteriorly to the condyle on T2 weighted images. This indicated possible calcifications or synovitis. The articular disc appeared deformed as the anterior band was pushed posteriorly and inferiorly by the calcified mass ( Fig. 2 B). The MRI showed only limited condylar mobility during mandibular opening. At the referral visit, a panoramic radiograph and computed tomography (CT) imaging of the TMJ were obtained. The panoramic radiograph showed asymmetrical condyles and an increased radiodensity in the area of the left condyle ( Fig. 2 A). The CT ( Fig. 2 C and D) showed calcifications anteriorly to the left condyle, which spread posteriorly, craniomedially of the condyle and laterally under the zygomatic process of the petrous part of the temporal bone. A bone scintigraphy using technetium-99m showed increased bone remodeling with unmodified blood flow in the left TMJ. Laboratory tests, including serum levels of uric acid did not show relevant abnormalities.
The diagnosis of a calcifying synovial process of the left TMJ, such as synovial (osteo)chondromatosis, was suspected. Disease progression and prolonged complaints of pain and limitation of mouth opening were indications for surgical treatment.
An arthroscopy of the left TMJ was performed to determine if removal of the articular disc during surgery was indicated ( Fig. 3 ). The arthroscopy showed a hemorrhagic fornix posterior, a strong inflammatory process, abnormal synovial folds and bulges and released fibrocartilage, resulting in a strongly affected joint surface with bleeding points (Wilkes stage V). The arthroscopy showed no intra-articular calcifications, adhesions or fibrous ankylosis. Cytologic evaluation of synovial fluid showed an inflammatory infiltrate, consisting of neutrophils, lymphocytes and histiocytes on a background of protein-rich material. No crystals were observed in the sample. There were also no signs of malignancy. Due to extended degenerative destruction of the condyle as well as the glenoid fossa with involvement of the joint capsule, resection of the joint with reconstruction by a TMJ alloprosthesis was chosen as surgical treatment.
A 3D analysis was performed and indicated that in order to correct the class 2 malocclusion, the placement of an alloprosthesis of the left TMJ had to be performed simultaneously with a unilateral sagittal split osteotomy (USSO) of the right side of the mandible ( Fig. 4 ). An alloplastic joint reconstruction was preferred over a costochondral graft for 3 reasons. First, the inflammatory response of the tissues to the crystal depositions could result in resorption or remodeling of the costochondral graft, resulting in malocclusion. Second, the rigidity of the prosthetic joint contributes to a more stable occlusion [ ]. Third, second donor site morbidity is prevented by using an alloprosthesis [ ]. A preauricular transmasseteric anteroparotid approach and preauricular hockey stick approach were used to access the joint and the ramus on the left side. The lateral pterygoid muscle was inseparably adherent and was therefore partially resected along with the left condyle ( Fig. 5 ). The articular disc and capsule, including the crystal depositions, were resected. The USSO on the right side was performed using a 3D-printed occlusal splint. A custom-made Biomet Microfixation TMJ replacement system (Biomet Microfixation, Jacksonville, FL, USA) was put into place with the intra-oral splint guiding the position of the mandible in relation to the upper jaw. A fat graft was harvested from the umbilical region and wrapped around the prosthesis to avoid fibrosis and heterotopic bone formation [ ].
Follow-up and outcomes
A postoperative panoramic radiograph and a CBCT were obtained and showed no remnants of calcifications. Postoperative facial nerve function was intact. The histopathological examination of the resected calcifications showed fibrous tissue with hyaline depositions, composed of rhomboid crystals and surrounded by a foreign-body giant cell reaction, chronic inflammation and iron deposition ( Fig. 6 ). The crystals were embedded in the joint capsule and were not present in the intra-articular space. The postoperative histopathological diagnosis of massive chondrocalcinosis with crystal deposition in the joint capsule was made.
At 6-week follow-up, the mouth opening was 32 mm and pain was absent. There was a minor hypo-aesthesia of the left lower lip and mental nerve area. At 6-month follow-up, the patient’s mouth opening was 41 mm and the normocclusion remained stable. The hypo-aesthesia was resolved and the patient had no pain or functional complaints. In majority of patients, chondrocalcinosis is a polyarticular disease [ ]. In this patient, no signs of chondrocalcinosis were found in the wrist and knee joints after X-ray examination.
The pathophysiology of chondrocalcinosis is characterized by the formation of CPPD crystals typically in the joint cartilage by ionic interaction of calcium to excessive pyrophosphate, produced by chondrocytes. This process is followed by a release of CPPD crystals in the joint space, which triggers phagocytosis and release of inflammatory mediators and eventually causes degeneration of the joint [ ]. Intramitochondrial presence of CPPD crystals suggests that a failure in the adenosine triphosphate or pyrophosphate metabolism is a possible factor in the pathophysiology of chondrocalcinosis [ ].
Based on clinical presentation, radiological and nuclear tests, the diagnosis of a calcifying synovial process of the left TMJ, such as synovial (osteo)chondromatosis, was suspected ( Table 1 ). Synovial chondromatosis is characterized by the intra-articular or extra-articular presence of cartilaginous or osteochondral nodules, resulting in decreased range of motion, preauricular pain and swelling. A delayed diagnosis is typical and leads to irreversible cartilaginous erosions [ ].
|Chondrocalcinosis of the TMJ||Synovial chondromatosis of the TMJ|
|Definition||Formation and the intra-articular or periarticular deposition of CPPD crystals [ ].||The intra-articular or periarticular presence of cartilaginous or osteochondral nodules [ ].|
|Symptoms||Limitation of mouth opening, preauricular swelling and pain, arthropathy, otalgia, conductive hearing loss.
[ , ]
|Limitation of mouth opening, preauricular swelling and pain [ ].|
|Diagnosis||Typically delayed [ ].||Typically delayed [ ].|
|Localization||Mostly intra-articular, sometimes periarticular [ ].||Mostly intra-articular, sometimes periarticular [ ].|
|T2-weighted images MRI||Hypointense signal [ ].||