Secondary Synovial Chondromatosis of the knee Joint-a case report

S. Kalaivanan, S. Chockalingam*, PR. Ramasamy

Department of Orthopedics, Kauvery Hospital, Trichy, India



Joint pain in an adult is a common presentation to an orthopaedic clinic. Rare conditions which cause knee symptoms should be considered in the differential diagnosis. We present a case report of synovial chondromatosis in an adult patient with intermittent symptoms of knee pain. His investigations included X ray and MRI scan. This condition can present as idiopathic or secondary to other knee pathologies. In our patient, this was secondary to knee arthritis. This was successfully treated with arthroscopic technique. We also reviewed the literature for this secondary synovial chondromatosis which confirmed its rarity

Keywords: Knee, Synovium, Chondromatosis, Joint, Loose bodies, Locking


Synovial chondromatosis is a rare benignant condition affecting joints. It is characterized by the development of multiple osteocartilaginous nodular loose bodies arising from the synovium of the joints. It most commonly affects the knee joint. Swelling, pain & limited range of movements are the common presentation by the patients.

Secondary synovial chondromatosis of the knee joint is a rare condition infrequently reported in the literature. We hence present one such patient with synovial chondromatosis of the knee Joint secondary to osteoarthritis due to its rarity. We also have treated this condition with knee arthroscopic technique with minimum morbidity and early recovery.

Case Presentation

A 71-year-old gentleman presented to our outpatient department with the complaint of recurrent Episodes of Right Knee Pain for past three years which had worsened over the past one month. He had no injury to knee. Pain and stiffness were the main complaints with intermittent swelling of the right knee. Clinical examination of the right knee joint (Fig. 1a and b) revealed knee effusion with knee flexion up to 120 degrees terminally painful associated with crepitus. There was no instability of knee joint. Neuro vascular examination was normal.


Fig. 1a and b. Clinical picture of Right Knee.


X-ray of knee joint shows multiple calcified loose bodies as shown in (Fig. 2a and b).


Fig. 2(a). Knee joint AP view and (b) Knee joint lateral view.

MRI of the right knee done (Fig. 3a and b) which shows joint effusion with multiple intra & extra articular loose bodies. Laboratory parameters were normal.


Fig. 3a and b. MRI showed loose bodies intra & extra articular.

Surgical technique

The patient underwent knee arthroscopy with arthroscopic removal of the multiple loose bodies (Fig. 4a and b). Initially diagnostic knee arthroscopy was done with anterio-lateral portal. Antero medial & postero medial portal were used to visualize and remove the loose bodies. It required patience to remove all intra articular loose bodies. Nearly 45 small size intra articular loose bodies were retrieved with baby Kocher forceps. These loose bodies were of pearl-white with size ranging from 0.2 to 1.5 cm (Fig. 5a and b).


Fig. 4(a). Shows Knee Arthroscopy and (b) shows Arthroscopic view of loose bodies


Fig. 5a and b. Showing pearl-white loose bodies with size ranging from 0.2 to 1.5 cm.

Minimal synovitis was present. Medial meniscus shows degeneration features. Partial synovectomy was done with radio frequency ablating Wand. Medial joint osteophyte was noted for which osteophytectomy were performed with 3.5 mm burr. After thorough debridement, the knee joint was irrigated with large amount of saline. The arthroscopic portals were closed with interrupted sutures. The surgical procedure was uneventful with tourniquet time of 90 min. The patient was discharged on the very next day with non-weight bearing mobilization.

Histopathological Examination

The multiple intra articular loose bodies sent to HPE shows central cartilaginous tissue composed of chondrocytes rimmed by calcified tissue consistent with Cartilaginous loose bodies with synovial chondromatosis (Fig. 6).


Fig. 6. Histopathological picture.

Follow up

The patient was followed up regularly. He showed gradual improvement with painless mobility of knee joint. Full weight bearing mobilization was done at 45 days. He had no recurrence of symptoms at two years. The plan radiograph of knee was done at two years post-OP were shown in the Fig. 6 shows knee joint with minimal calcified loose bodies in the soft tissue plane which was not excised in the primary surgery. This was explained to the patient as the extra articular chondromatosis rarely cause significant symptoms.


Fig. 7. Plain radiograph of knee at 2yrs post op.


Synovial chondromatosis is a very rare benignant lesion of synovium of joints characterized by multiple intra-articular cartilaginous loose bodies. Also, extra-articular affection is seen if the osteocartilagenous loose bodies evades via the joint capsule in to the soft tissue planes of underlying bursa [1]. The disease is classified in to primary or secondary type. The cause for the primary Synovial chondromatosis is idiopathic which occurs in third or fourth decade whereas secondary Synovial chondromatosis causes are trauma, and inflammatory joint pathologies which most commonly seen in fifth or sixth decade [2].

The disease usually affects a single large joint and occasionally presents outside the joint as in our patient. The knee joint is affected in 60–70% of cases with next mostly affected are the shoulder, elbow and hip joints [3]. In this disease, the mesenchymal cells contiguous with synovial cells undergo cartilaginous metaplasia which finally forms nodules that later in the disease process gets detached and become intra articular loose bodies [4]. These loose bodies had a propensity to unite with itself and to calcify. Patients clinically presents with joint pain and swelling with limited range of movements and sometimes locking of joints. Pigmented villo nodular synovitis is the usual differential diagnosis of this disease.

Davis et al. reported a relative risk of 5% for malignant degeneration in primary chondromatosis cases in 1988 [5]. A simple plain radiograph will show the calcified multiple loose bodies in almost up to 95 % of cases. Magnetic Resonance Imaging (MRI) is helpful in cases where plain radiograph does not show any features of calcification [1]. The goal of treatment is to reduce the pain symptoms and enhance the range of movements, and to avoid the progression to early arthritis by removal of the intra articular loose bodies [6].

Removal of loose bodies can be done with open surgery to the knee. We have used arthroscopic removal of the loose bodies by three portal technique which gives better results being less invasive offering advantages of diminished pain, earlier recovery, increased patient satisfaction, and less morbidity in synovial chondromatosis [4]. To the best of the authors knowledge, a very few cases are reported in the literature of Secondary Synovial chondromatosis of the Knee Joint treated by arthroscopic approach [7–9].


Secondary Synovial chondrometaplasia of the Knee Joint is uncommon condition causing Knee pain. It can cause pain and recurrent swelling. We have successfully treated this condition with arthroscopic technique which demands expertise and patience.


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