Localized pigmented villonodular synovitis presenting as recurrent dislocation of the patella

Pigmented villonodular synovitis does not influence the outcomes following cruciate-retaining total knee arthroplasty: a case-control study with minimum 5-year follow-up

BACKGROUND

Pigmented villonodular synovitis (PVNS) is a rare synovial disease with benign hyperplasia, which has been successfully treated with total knee arthroplasty (TKA). The purpose of this study was to investigate the middle-term follow-up outcomes of cruciate-retaining (CR) TKA in patients with PVNS.

METHODS

From January 2012 to December 2014, a retrospective study was conducted in 17 patients with PVNS who underwent CR TKA as PVNS group. During this period, we also selected 68 patients with osteoarthritis who underwent CR TKA (control group) for comparison. The two groups matched in a 1:4 ratio based on age, sex, body mass index, and follow-up time. The range of motion, Knee Society Score, revision rate, disease recurrence, wound complications, and the survivorship curve of Kaplan-Meier implant were assessed between the two groups.

RESULTS

All patients were followed up at least 5 years. There was no difference in range of motion and Knee Society Score between the two groups before surgery and at last follow-up after surgery (p > 0.05). In the PVNS group, no patients with the recurrence of PVNS were found at the last follow-up, one patient underwent revision surgery due to periprosthetic fracture, and three patients had stiffness one year after surgery (17.6% vs 1.5%, p = 0.005; ROM 16-81°), but no revision was needed. At 7 years, the implant survivorship was 90.0% in the PVNS group and 96.6% in the control group (p = 0.54).

CONCLUSIONS

This study demonstrated that the function of patients with PVNS who underwent CR TKA had been significantly improved, and the survival rate of implants in these patients was similar to the patients with OA. Consequently, the patients with PVNS who underwent CR TKA might be an achievable option. However, these patients should pay more attention to the occurrence of postoperative stiffness complications.

Pigmented villonodular synovitis in pediatric population: review of literature and a case report

BACKGROUND

Pigmented villonodular synovitis (PVNS) is a rare proliferative process in children that mostly affects the knee joint.

CASE PRESENTATION

The study follows the case of a 3-year-old boy presenting recurrent patellar dislocation and PVNS. Due to symptoms such as chronic arthritis, he had been taking prednisolone and methotrexate for 6 months before receiving a definitive diagnosis. After a period of showing no improvements from his treatment, he was referred to our center and was diagnosed with local PVNS using magnetic resonance imaging (MRI). The patient was treated for his patellar dislocation by way of open synovectomy, lateral retinacular release, and a proximal realignment procedure, with no recurrence after a 24-month follow-up.

CONCLUSION

PVNS may appear with symptoms resembling juvenile idiopathic arthritis, thus the disease should be considered in differential diagnosis of any inflammatory arthritis in children. PVNS may also cause mechanical symptoms such as patellar dislocation. In addition to synovectomy, a realignment procedure can be a useful method of treatment.

A case of intra-articular synovial lipoma of the knee joint causing patellar dislocation

Intra-articular synovial lipoma is rare and clinically manifested mostly by mass effect and occasionally by torsion of the stalk. Patellar dislocation rarely occurs owing to a mass effect of intra-articular tumor of the knee joint. The authors present a case of large intra-articular synovial lipoma at the lateral gutter of the knee joint, which presents as patellar dislocation. A 19-year-old man visited our clinic due to pain and limitation of motion owing to mass at his left knee. MRI revealed an intra-articular soft tissue mass at the lateral gutter of the knee joint with considerable mass effect displacing patella from the trochlear groove. Excisional biopsy confirmed the diagnosis of lipoma, and the final diagnosis was intra-articular synovial lipoma with clinical information. The final radiograph showed well-aligned patella on the trochlear groove. After marginal excision, there was no recurrence or tumor-related morbidity.

Bilateral patellar dislocation associated with alpha-mannosidase deficiency

Mannosidosis is an extremely rare genetic disease characterized by a deficiency of the lysosomal enzyme, alpha-mannosidase. This enzyme is necessary for cleavage of mannose from many glycoproteins. In the absence of this enzyme, mannose accumulates in cells throughout the body, including the joints and the synovium. This disease causes many skeletal changes including dysostosis multiplex, synovial hypertrophy, and Charcot-type joints. We report the case of a girl, aged 9 years and 6 months, who developed bilateral patellar dislocation and severe synovial hypertrophy secondary to alpha-mannosidase deficiency. Her disease was further complicated by Charcot elbow and bilateral hip and elbow avascular necrosis.

Localized pigmented villonodular synovitis in the anteromedial compartment of the knee associated with cartilage lesions of the medial femoral condyle: report of a case and review of the literature

Localized pigmented villonodular synovitis (PVNS) of the knee is an uncommon entity, presenting with different clinical signs and symptoms. We report on a case of a 42-year-old woman who presented with a 3-year history of knee pain and mechanical problems such as locking. On examination she was found to have a palpable and painful mass over the anteromedial joint line. Magnetic resonance imaging (MRI) revealed a soft tissue mass in the anteromedial compartment of the knee joint. The lesion was completely resected arthroscopically, and histologic examination confirmed the diagnosis of localized PVNS. The patient was free of symptoms, and MRI examination showed no evidence of recurrence at 1-year follow-up.

Arthroscopic treatment of solitary benign intra-articular lesions of the knee that cause mechanical symptoms

PURPOSE

Most cases of knee locking and giving-way are caused by meniscal tears, loose bodies, or chondral lesions. Intra-articular benign tumors or tumor-like lesions can present with symptoms that resemble acute mechanical derangement. From a database of 2,200 arthroscopic interventions, 19 cases of intra-articular masses that presented with catching and locking symptoms in the knee were retrospectively analyzed.

TYPE OF STUDY

Case series.

METHODS

Our review revealed 33 patients with benign intra-articular masses in the knee joint. Nineteen of these individuals had sought medical attention for mechanical symptoms of catching or locking. The other 14 patients had a variety of symptoms including pain, swelling, and limitation of knee motion, but did not have mechanical symptoms. Age, sex, history of trauma, knee pain and effusion, medical illnesses, physical examination, arthroscopic findings, and pathologic findings were noted.

RESULTS

The average age of the 6 male and 13 female patients was 37.5 years (range, 18 to 58 years). Preoperative magnetic resonance imaging confirmed the diagnosis in 7 cases and 12 cases were diagnosed during knee arthroscopy. The mean follow-up time after surgery was 52.5 months (range, 6 to 120 months). Pathologic examination of the lesions revealed 15 cases of localized pigmented villonodular synovitis (79%), 1 lipoma arborescens (5%), 1 pseudocyst (5%), and 2 nonspecific synovial masses (11%). None of the lesions showed malignant transformation.

CONCLUSIONS

Solitary benign intra-articular lesions should be considered a rare cause of mechanical knee symptoms. Localized pigmented villonodular synovitis originating from the extensor mechanism or fat pad is the most common solitary intra-articular mass lesion in the knee and usually arises in the patellofemoral compartment. Recurrence has not occurred in our series, which includes 14 of 19 patients with greater than 24 months follow-up.

LEVEL OF EVIDENCE

Level IV.

Differential diagnosis of tumours and tumour-like lesions of the infrapatellar (Hoffa?s) fat pad: pictorial review with an emphasis on MR imaging

A variety of intrinsic and extrinsic tumours and tumour-like conditions may affect the infrapatellar (Hoffa's) fat pad (IFP). MR imaging is the technique of choice in evaluating these conditions, but correlation with radiographs is important to identify those lesions producing mineralization. This pictorial review illustrates the spectrum of mass-like lesions that can affect the IFP, emphasizing the radiographic and MR findings that suggest a specific diagnosis.

Localized pigmented villonodular synovitis of the knee

Eight patients with localized pigmented villonodular synovitis (LPVNS) of the knee were treated with arthroscopic and open techniques, with diagnosis confirmed by histological examination. Average patient age was 29 years (range: 13-50 years). At arthroscopy, all lesions except one were in the anterior compartment of the involved knee. Treatment consisted of complete local excision with partial synovectomy. This procedure was completed arthroscopically in seven patients. No recurrence was reported at average 24-month follow-up (range: 12-33 months). Arthroscopy is a valuable tool in the diagnosis and treatment of LPVNS.