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Synovial osteochondromatosis of the cruciate ligament
Case Report
Synovial Osteochondromatosis of the Cruciate Ligament Ahmed Mubashir, F.R.C.S., M.Sc. (Orth), and Derek R. Bickerstaff, M.D., F.R.C.S., F.R.C.S (Edin)
Summary: An unusual case of synovial chondromatosis of the cruciate ligaments is reported that resulted principally in a loss of function, secondary to a mechanical block to extension. Magnetic resonance imaging was useful in directing surgery, but not in making the formal diagnosis. Key Words: Knee—Ganglion cyst— Arthroscopic resection—Cruciate ligaments—Synovial chondromatosis.
S
ynovial osteochondromatosis is characterized by the metaplasia of the subintimal tissue of synovial joints, bursae, and tendon sheaths. The most prevalent sites are the knee, elbow, and hip joint.1-4 Trauma has been implicated but never been confirmed as a precipitating factor in the development of this condition. The common clinical findings are swelling, pain, or tenderness over the joint, and limitations of function. Conversely, the patient may commonly complain of no symptoms at all. To our knowledge, no previous cases have been described of this condition affecting the cruciate ligaments in the knee joint. Magnetic resonance imaging (MRI) was useful in guiding the decision regarding to the surgical approach. CASE REPORT A 46-year-old school dinner lady presented with 3-year history of pain and swelling in the right knee. Initially the symptoms were intermittent, lasting a few days at a time. She had an arthroscopic examination on two separate occasions but no formal diagnosis was made. She had intra-articular injection of steroids and, although the first attempt was transiently successful, From the Department of Orthopaedics, Northern General Hospital, N.H.S. Trust, Sheffıeld, England. Address correspondence and reprint requests to Ahmed Mubashir, F.R.C.S., M.Sc. (Orth), Northern General Hospital, N.H.S. Trust, Herries Rd, Sheffıeld S5 7AU, England. r 1998 by the Arthroscopy Association of North America 0749-8063/98/1406-1837$3.00/0
subsequent efforts had been only marginally beneficial. She was admitted to the rheumatic disease centre for assessment by the physical therapist with a provisional diagnosis of sero-negative arthritis. Radiographic and serological tests did not show any abnormality. Her symptoms progressed over a 6-month period such that at presentation she was complaining of increasing pain with activity and progressive flexion deformity. At presentation she had a 45° extension block and marked wasting of the quadriceps and hamstrings muscles. She could only walk with the aid of crutches. An MRI scan showed a ganglion related to the anterior and posterior cruciate ligaments. Arthroscopy revealed a very curious appearance with multiple swellings around the cruciate ligaments. The rest of the synovium appeared normal. The lesions were removed arthroscopically using standard anterior and posteromedial portals. Histological testing proved them to be consistent with synovial chondromatosis. After surgery her symptoms improved in that her pain settled and knee movement improved. Unfortunately, 3 to 6 months later she relapsed, with an identical recurrence of symptoms. At this time, MRI scans showed further lesions but more so related to the posterior cruciate ligament. In view of the recurrent nature of the lesion it was elected to perform a formal open debridement of the posterior recess of the knee. A standard posterior approach to the knee was made. Multiple soft irregular lesions were removed, the largest measuring 1 cm (Fig 1), from around the posterior cruciate ligament. A synovectomy was per-
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 14, No 6 (September), 1998: pp 627–629
627
628
A. MUBASHIR AND D. R. BICKERSTAFF Although MRI has not been helpful in limited studies in determining specific histology of synovial lesions, synovial irregularity and hypertrophy is well demonstrated.7 In this case, MRI was unable to help us make a formal diagnosis, but was it was very useful in localizing the lesions causing the mechanical block and thereby directing the surgical approach (Fig 2). Recent pathological studies of osteochondromatosis have shown an increase of type II collagen and conversion resulting in metaplasia of the synovial tissue with the proliferation of the cartilaginous nodules. In this case, these changes apparently occurred in a very localized area of the knee, which is distinctly unusual. Therefore, this case demonstrates an unusual cause of mechanical block to the knee and the use of MRI to direct surgery. The initial arthroscopic synovectomy of the posterior recess proved to be inadequate, resulting in a more formal open approach.
FIGURE 1. The largest lesion removed from around the posterior cruciate ligament.
formed of the posterior recess and at this point full extension was possible. Postoperatively, an epidural anesthesia was maintained for 48 hours. The knee was placed on continuous passive motion with a range of 0° to 90°, and the patient was placed in a resting splint in extension. The histological examination again confirmed the diagnosis of synovial chondromatosis. Six months later, she maintains a full range of knee movements and remains symptom free.
CONCLUSION This case represents an unusual cause of a mechanical block to the knee. The localized nature of the lesion was identified by MRI scan, but a formal diagnosis was made only on histological examination. Although an arthroscopic synovectomy was adequate in clearing
DISCUSSION This case illustrates a curious cause of a mechanical block to extension. Synovial chondromatosis is an uncommon but well-recognized condition and, to our knowledge, has not been reported as being localized solely to the synovium over the cruciate ligaments and causing such a mechanical problem. Initially it was believed that the lesions on the anterior cruciate ligament were the cause of the loss of extension secondary to notch impingement. It later became apparent that the shear volume of chondral tissue in the posterior recess blocked full extension. This was dealt with the second open procedure. Synovial osteochondromatosis may be classified as primary or secondary process.5-6 It is considered to be primary when it is present in the normal joints and secondary when it is associated with pre-existing degenerative changes, which was not the case in this patient. The primary process is more likely to recur.
FIGURE 2. MR T-1 and T2-weighted images showing cystic lesion around the posterior cruciate ligament.
SYNOVIAL OSTEOCHONDROMATOSIS the notch, an open synovectomy was required to adequately deal with the posterior recess. REFERENCES 1. Milgram JW. Synovial osteochondromatosis: A histological study of thirty cases. J Bone Joint Surg Am 1977;59:792-801. 2. Jefferys TE. Synovial chondromatosis. J Bone Joint Surg Br 1967;49:530-534.
629
3. Murphy FP, Drennan JC, Sullivan CR. Articular synovial chondromatosis. J Bone Joint Surg Am 1962;44:77-86. 4. Simm FH, Dalhin DC, Ivins JC. Extraarticular synovial chondromatisis. J Bone Joint Surg Am 1977;59:492-495. 5. Milgram JW. Synovial osteochondramatosis in the foot. Bull Hosp Joint Dis 1987;47:245. 6. Sims RE, Genant HK. Magnetic resonance imaging of joint disease. Radiol Clin North Am 1986;24:179-188. 7. Sundram M, McGuire MH, Fletcher J, et al. Magnetic resonance imaging of lesions of synovial origin. Skeletal Radiol 1986;15: 110-116.
Synovial Osteochondromatosis of the Cruciate Ligament Ahmed Mubashir, F.R.C.S., M.Sc. (Orth), and Derek R. Bickerstaff, M.D., F.R.C.S., F.R.C.S (Edin)
Summary: An unusual case of synovial chondromatosis of the cruciate ligaments is reported that resulted principally in a loss of function, secondary to a mechanical block to extension. Magnetic resonance imaging was useful in directing surgery, but not in making the formal diagnosis. Key Words: Knee—Ganglion cyst— Arthroscopic resection—Cruciate ligaments—Synovial chondromatosis.
S
ynovial osteochondromatosis is characterized by the metaplasia of the subintimal tissue of synovial joints, bursae, and tendon sheaths. The most prevalent sites are the knee, elbow, and hip joint.1-4 Trauma has been implicated but never been confirmed as a precipitating factor in the development of this condition. The common clinical findings are swelling, pain, or tenderness over the joint, and limitations of function. Conversely, the patient may commonly complain of no symptoms at all. To our knowledge, no previous cases have been described of this condition affecting the cruciate ligaments in the knee joint. Magnetic resonance imaging (MRI) was useful in guiding the decision regarding to the surgical approach. CASE REPORT A 46-year-old school dinner lady presented with 3-year history of pain and swelling in the right knee. Initially the symptoms were intermittent, lasting a few days at a time. She had an arthroscopic examination on two separate occasions but no formal diagnosis was made. She had intra-articular injection of steroids and, although the first attempt was transiently successful, From the Department of Orthopaedics, Northern General Hospital, N.H.S. Trust, Sheffıeld, England. Address correspondence and reprint requests to Ahmed Mubashir, F.R.C.S., M.Sc. (Orth), Northern General Hospital, N.H.S. Trust, Herries Rd, Sheffıeld S5 7AU, England. r 1998 by the Arthroscopy Association of North America 0749-8063/98/1406-1837$3.00/0
subsequent efforts had been only marginally beneficial. She was admitted to the rheumatic disease centre for assessment by the physical therapist with a provisional diagnosis of sero-negative arthritis. Radiographic and serological tests did not show any abnormality. Her symptoms progressed over a 6-month period such that at presentation she was complaining of increasing pain with activity and progressive flexion deformity. At presentation she had a 45° extension block and marked wasting of the quadriceps and hamstrings muscles. She could only walk with the aid of crutches. An MRI scan showed a ganglion related to the anterior and posterior cruciate ligaments. Arthroscopy revealed a very curious appearance with multiple swellings around the cruciate ligaments. The rest of the synovium appeared normal. The lesions were removed arthroscopically using standard anterior and posteromedial portals. Histological testing proved them to be consistent with synovial chondromatosis. After surgery her symptoms improved in that her pain settled and knee movement improved. Unfortunately, 3 to 6 months later she relapsed, with an identical recurrence of symptoms. At this time, MRI scans showed further lesions but more so related to the posterior cruciate ligament. In view of the recurrent nature of the lesion it was elected to perform a formal open debridement of the posterior recess of the knee. A standard posterior approach to the knee was made. Multiple soft irregular lesions were removed, the largest measuring 1 cm (Fig 1), from around the posterior cruciate ligament. A synovectomy was per-
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 14, No 6 (September), 1998: pp 627–629
627
628
A. MUBASHIR AND D. R. BICKERSTAFF Although MRI has not been helpful in limited studies in determining specific histology of synovial lesions, synovial irregularity and hypertrophy is well demonstrated.7 In this case, MRI was unable to help us make a formal diagnosis, but was it was very useful in localizing the lesions causing the mechanical block and thereby directing the surgical approach (Fig 2). Recent pathological studies of osteochondromatosis have shown an increase of type II collagen and conversion resulting in metaplasia of the synovial tissue with the proliferation of the cartilaginous nodules. In this case, these changes apparently occurred in a very localized area of the knee, which is distinctly unusual. Therefore, this case demonstrates an unusual cause of mechanical block to the knee and the use of MRI to direct surgery. The initial arthroscopic synovectomy of the posterior recess proved to be inadequate, resulting in a more formal open approach.
FIGURE 1. The largest lesion removed from around the posterior cruciate ligament.
formed of the posterior recess and at this point full extension was possible. Postoperatively, an epidural anesthesia was maintained for 48 hours. The knee was placed on continuous passive motion with a range of 0° to 90°, and the patient was placed in a resting splint in extension. The histological examination again confirmed the diagnosis of synovial chondromatosis. Six months later, she maintains a full range of knee movements and remains symptom free.
CONCLUSION This case represents an unusual cause of a mechanical block to the knee. The localized nature of the lesion was identified by MRI scan, but a formal diagnosis was made only on histological examination. Although an arthroscopic synovectomy was adequate in clearing
DISCUSSION This case illustrates a curious cause of a mechanical block to extension. Synovial chondromatosis is an uncommon but well-recognized condition and, to our knowledge, has not been reported as being localized solely to the synovium over the cruciate ligaments and causing such a mechanical problem. Initially it was believed that the lesions on the anterior cruciate ligament were the cause of the loss of extension secondary to notch impingement. It later became apparent that the shear volume of chondral tissue in the posterior recess blocked full extension. This was dealt with the second open procedure. Synovial osteochondromatosis may be classified as primary or secondary process.5-6 It is considered to be primary when it is present in the normal joints and secondary when it is associated with pre-existing degenerative changes, which was not the case in this patient. The primary process is more likely to recur.
FIGURE 2. MR T-1 and T2-weighted images showing cystic lesion around the posterior cruciate ligament.
SYNOVIAL OSTEOCHONDROMATOSIS the notch, an open synovectomy was required to adequately deal with the posterior recess. REFERENCES 1. Milgram JW. Synovial osteochondromatosis: A histological study of thirty cases. J Bone Joint Surg Am 1977;59:792-801. 2. Jefferys TE. Synovial chondromatosis. J Bone Joint Surg Br 1967;49:530-534.
629
3. Murphy FP, Drennan JC, Sullivan CR. Articular synovial chondromatosis. J Bone Joint Surg Am 1962;44:77-86. 4. Simm FH, Dalhin DC, Ivins JC. Extraarticular synovial chondromatisis. J Bone Joint Surg Am 1977;59:492-495. 5. Milgram JW. Synovial osteochondramatosis in the foot. Bull Hosp Joint Dis 1987;47:245. 6. Sims RE, Genant HK. Magnetic resonance imaging of joint disease. Radiol Clin North Am 1986;24:179-188. 7. Sundram M, McGuire MH, Fletcher J, et al. Magnetic resonance imaging of lesions of synovial origin. Skeletal Radiol 1986;15: 110-116.