Synovial Abnormalities Research Articles

Comparison of the efficacy of prednisone and cyclosporine for treatment of dogs with primary immune-mediated polyarthritis.

To compare efficacy between cyclosporine and prednisone for treatment of primary immune-mediated polyarthritis (IMPA) in dogs. Randomized controlled clinical trial. 20 client-owned dogs with primary IMPA. Dogs were randomly assigned to receive prednisone (starting at 1 mg/kg [0.45 mg/lb], PO, q 12 h; n = 10) or cyclosporine (5 mg/kg [2.3 mg/lb], PO, q 12 h; 10) for 90 days. Cyclosporine-treated dogs also received carprofen, tramadol, or both for the first 7 days for analgesia. Data collection, physical examination, and cytologic analysis of synovial fluid samples were performed on days 0, 14, 45, and 90. Trough whole blood cyclosporine concentrations were determined on days 7 to 17 for cyclosporine-treated dogs. Treatment failure was defined as lack of clinical improvement by day 14, lack of cytologic improvement by day 45, or need to change treatment because of adverse effects. Treatment was successful for 7 prednisone-treated dogs and 7 cyclosporine-treated dogs. Absence of synovial fluid cytologic abnormalities on day 45 was identified for 5 prednisone-treated dogs and 8 cyclosporine-treated dogs. Prednisone-treated dogs were more likely to develop polyuria, polydipsia, and polyphagia than were cyclosporine-treated dogs. Opportunistic infections (ie, demodicosis or Erysipelothrix bacteremia) were identified in 2 cyclosporine-treated dogs and 0 prednisone-treated dogs, and diarrhea developed in 1 cyclosporine-treated dog, requiring treatment discontinuation. Although the number of dogs evaluated was small, limiting generalizability, results of this study suggested that cyclosporine offers promise as a suitable alternative to prednisone for treatment of IMPA in dogs.

Disk abnormality coexists with any degree of synovial and osseous abnormality in the temporomandibular joints of children with juvenile idiopathic arthritis

MRI manifestation of temporomandibular joint arthritis is frequently reported in children with juvenile idiopathic arthritis. However, little attention has been paid to temporomandibular joint disk abnormalities. To assess combinations of MRI findings in the symptomatic temporomandibular joint in children with juvenile idiopathic arthritis with focus on disk abnormalities. This was a retrospective study of 46 patients with juvenile idiopathic arthritis, mean age 12 years (range: 5-17 years). Mean disease duration was 70 months (standard deviation: 61 months). MR images of 92 temporomandibular joints were scored for thickness of abnormally enhancing synovium (synovitis), joint effusion, bone marrow oedema, abnormal bone shape, bone erosion and disk abnormalities. The 92 temporomandibular joints were categorized as A: No synovitis and normal bone shape (30/92; 33%), B: Synovitis and normal bone shape (14/92: 15%), C: Synovitis and abnormal bone shape (38/92; 41%) and D: No synovitis but abnormal bone shape (10/92; 11%). Thirty-six of the 46 patients (78%) had synovitis and 33/46 (72%) had abnormal bone shape, most frequently in combination (30/46; 65%). Disk abnormalities (flat disk, fragmented disk, adherent disk and displaced disk) were found in 29/46 patients (63%). Disk abnormalities were found in all categories of juvenile idiopathic arthritis involved temporomandibular joints (B: 8/14 [57%]; C: 25/38 [66%] and D: 7/10 [70%]). Disk displacement was found in half of the joints (7/14) in category B. Synovitis was most pronounced in this category. Disk abnormalities were frequent. Disk displacement also occurred in joints with early temporomandibular joint arthritis, i.e., with normal bone shape. Other disk abnormalities were found in joints with bone abnormalities. Attention should be paid to disk abnormalities both in early and long-standing temporomandibular joint arthritis in children with juvenile idiopathic arthritis.

Comparison of the histopathological findings of patients with diabetic and idiopathic carpal tunnel syndrome

This study is aimed to investigate whether there are any histopathological differences between diabetic and idiopathic carpal tunnel syndromes. The biopsy specimens were taken from transverse carpal ligament (TCL), tenosynovium adjacent to median nerve and epineurium of median nerve and evaluated in 47 patients (21 diabetic and 26 idiopathic) who were diagnosed with carpal tunnel syndrome (CTS) and treated surgically with open carpal tunnel release. Fibroblast proliferation, fibrosis, perivascular inflammation, oedema, vascular proliferation and vascular wall thickness were determined and scored in all specimens. There weren't any histopathological abnormalities in TCL specimens of both groups. Synovial hyperplasia, fibrosis and perivascular inflammation were not observed in tenosynovial analysis of both groups. Diabetic CTS patients, when compared with idiopathic CTS patients, had higher rates of synovial edema (idiopathic CTS 57 %, diabetic CTS 87 %), vascular proliferation (idiopathic CTS 30.8 %, diabetic CTS 90.5 %) and increased vascular wall thickness (idiopathic CTS 11.5 %, diabetic CTS 90.5 %). There was no oedema, fibrosis and perivascular inflammation of the epineurium in specimens of either group. But increases in vascular proliferation (idiopathic CTS 7.7 %, diabetic CTS 71.4 %) and vascular wall thickness (idiopathic CTS 3.8 %, diabetic CTS 71.4 %) was seen in the epineurium of diabetic patients and these differences were statistically significant (p < 0.05). Because of the severe synovial and epineurial histopathological abnormalities and inadequate neural regeneration capacity, surgical open carpal tunnel decompression should be planned earlier in diabetic CTS patients. Further studies should be considered to evaluate the histopathological features of diabetic CTS patients early in the course of the disease.

SAT0560 The in Vivo Role of Bone Specific Ephb4 Receptor Overexpression in Osteoarthritic Synovial Membrane

BackgroundOsteoarthritis (OA) is characterized by progressive joint destruction including synovial membrane inflammation and abnormalities including fibrosis. Members of the Eph/ephrin family, the EphB4 receptor and its specific ligand ephrin-B2, were...

AB1002 Do Foot Posture and the Age-Related Variations Led to Sonographic Abnormalities in the Paediatric Healthy Foot?

BackgroundAs ultrasonography has proven to be a helpfulness tool for detecting articular and periarticular foot disease in juvenile idiopathic arthritis, the interpretation of some findings such as effusion or power...

Response Evaluation of Musculoskeletal Involvement in Patients With Deep Morphea Treated With Methotrexate and Prednisolone: A Combined MRI and Clinical Approach

The purpose of this article is to explore the role of MRI in monitoring musculoskeletal involvement in patients with morphea who are undergoing treatment with methotrexate and prednisolone. Twenty-two consecutive patients (six men and 16 women; median age, 52 years) with systemic scleroderma and deep morphea prospectively underwent whole-body MRI twice, before treatment (time 1) and during follow-up after 6-12 months (time 2). Images were evaluated for abnormal signal intensity or thickening of sub-cutaneous fatty tissue septa, muscular fasciae, intramuscular perifascial septa, muscle signal intensity, and articular or tendon sheath synovial abnormalities on STIR and gadolinium-enhanced scans. For clinical assessment, the localized scleroderma (morphea) severity index and a 0-6 pain score were applied. From a clinical point of view, none of our patients had progression of the disease, 12 patients were responders (defined as an improvement of localized scleroderma severity index and pain score ≥ 50%), and 10 patients had stable disease. Among responders, the number of patients with subcutaneous septal thickening (time 1, n = 9; time 2, n = 2), fascial enhancement (time 1, n = 8; time 2, n = 3), and articular synovitis (time 1, n = 5; time 2, n = 1) decreased more than in the stable disease group (subcutaneous septal thickening: time 1, n = 9; time 2, n = 8; fascial enhancement: time 1, n = 5; time 2, n = 5; articular synovitis: time 1, n = 8; time 2, n = 6). Subcutaneous thickening, fascial thickening, and fascial enhancement were scored significantly lower at follow-up MRI in responders. MRI findings were sensitive to changes in musculoskeletal manifestations in patients with deep morphea undergoing systemic treatment with methotrexate and prednisolone. Thus, MRI can be recommended as an additional tool for response monitoring.

Magnetic resonance imaging findings in patients with systemic scleroderma and musculoskeletal symptoms

To explore the role of whole-body magnetic resonance imaging (MRI) in detecting musculoskeletal involvement in patients with systemic scleroderma and musculoskeletal symptoms. Eighteen consecutive patients (8 men, 10 women) with systemic scleroderma (median age 46 years) presenting with musculoskeletal complaints underwent whole-body MRI at 1.5 T. Images were evaluated for abnormal signal intensity and/or thickening of subcutaneous fatty tissue septa, muscular fasciae, intramuscular perifascial septa, muscle signal intensity and articular or tendon sheath synovial abnormalities on STIR and post-gadolinium scans. Additionally, C-reactive protein, creatinine kinase and the modified Rodnan skin score were determined. MRI indicated evidence of fasciitis, articular synovial inflammation, and subcutaneous thickening in 16 (89 %) patients. MRI findings were compatible with myopathy or myositis in 14 (78 %) patients, tenosynovitis in 11 (61 %) patients and enthesitis in 10 (56 %) patients. Typically, these manifestations were distributed symmetrically and mostly generalised. We only found few correlations with modified Rodnan skin score, C-reactive protein and creatinine kinase. In patients with systemic scleroderma experiencing musculoskeletal symptoms, whole-body MRI is able to detect involvement of muscles, fasciae, joints and entheses more confidently compared with clinical and laboratory parameters.

Ultrasound-detected synovial abnormalities are frequent in clinically inactive juvenile idiopathic arthritis, but do not predict a flare of synovitis

ObjectivesTo investigate whether children with juvenile idiopathic arthritis (JIA) in clinical remission have subclinical synovial disease on ultrasound, and whether ultrasound abnormalities predict an early flare of synovitis.MethodsThirty-nine consecutive children...

Hip Arthroscopy: Current Indications and Setup

During the last 2 decades, hip arthroscopy evolved from a means of diagnosis to therapeutic tool to a minimally invasive method of treating hip pathology. Well-established indications of hip arthroscopies include debridement of loose bodies and treatment of labral tears. Newer indications for hip arthroscopy include treatment for femoroacetabular impingement, acetabular dysplasia, avascular necrosis of the femoral head, septic hip, degenerative disease, trauma, adhesive capsulitis, peritrochanteric disorders (including trochanteric bursitis, external snapping iliotibial band and guteus medius and minimus tears), and synovial abnormalities (including pigmented villonodular synovitis, synovial chondromatosis and rheumatoid arthritis). Hip arthroscopy may also be used to remove foreign bodies caused by trauma and to evaluate total hip arthroplasties for revision and infection. The setup of hip arthroscopies also has evolved to accommodate these indications, including the development of newer traction devices to allow access to various compartments around the hip. More accessory portals are created in anatomically safe locations to allow for correction of different hip pathologies that were previously treated with arthrotomies. This article describes the most current indications and setup in hip arthroscopies today.

Imaging of Impingement Lesions in the Ankle

Ankle impingement and instability are well-recognized complications of ankle sprain. Ankle impingement is an important cause of chronic ankle pain in active populations, particularly in the professional athlete. Depending on anatomical location and the structures involved, impingement syndromes are classified into anterolateral, anterior, posterior, posteromedial, and anteromedial types. Clinically, impingement syndromes are characterized by painful limitation of full-ankle movement. Ankle impingement results from repetitive subclinical trauma due to overuse injuries, which, in the subacute or chronic situation, lead to abnormal osseous and soft-tissue thickening within the ankle joint. Various imaging techniques can be used in the diagnosis of ankle impingement. Usually, radiography is the initial imaging technique performed to rule out bony trauma and identify potential anatomical bony abnormalities. Use of computed tomography and isotope bone scanning is largely superseded by magnetic resonance imaging, although with variable sensitivity and specificity. Arthrographic techniques, using computed tomography or magnetic resonance, are useful for exquisite demonstration of capsular recesses and synovial abnormalities. Imaging-guided injection techniques can be used in the management of impingement for pain ablation and to aid clinical diagnosis, especially in hind foot pain.

MR Imaging of Synovial Disorders of the Knee

Synovial membranes line the diarthrodial (movable) joints, bursae, and tendon sheaths of the body. The primary function of this specialized, vascular tissue is to serve as a filter system that lubricates and nourishes the articular structures as well as serving as a shock-absorber. The synovium is affected by a variety of disorders that can be localized to a specific articulation or can be systemic in nature. These include inflammatory, infectious, degenerative, traumatic, or neoplastic categories of disease. Further, MR imaging provides an excellent non-invasive tool for the evaluation of the synovium and synovial-based processes. This article will discuss technical considerations pertinent to the MR imaging evaluation of synovial processes in the knee; will review the synovial and bursal anatomy of the knee as well as the imaging characteristics of general synovial abnormalities and their diagnostic implications. In addition, it will review specific synovial processes and their characteristic MR imaging findings.

Dorsoproximal proximal phalanx osteochondral fragmentation in 117 Warmblood horses

The objective of the present study was to determine clinical and arthroscopic characteristics associated with dorsoproximal proximal phalanx (P1) fragments in Warmblood horses, as well as to examine their histopathological appearance. One hundred sixty-eight fragments were removed from 150 fetlocks of 117 Warmblood horses. Details of signalment and results of clinical examination were collected prior to surgery. After arthroscopic fragment removal and joint evaluation for synovial and/or cartilage abnormalities, the fragments were measured and evaluated histopathologically. The vast majority of the fragments (95.2%) were found medially, without predilection for front or hind limbs. In 10% of the joints, more than one fragment was present. The mean size of the fragments was 6.8 +/- 2.6 mm. Only eight horses presented fetlock-related lameness. Horses of seven years of age and older (OR = 13.32; p = 0.033) and the presence of more than one fragment (OR = 11.12; p = 0.016) were significantly associated with lameness. Arthroscopic evaluation revealed one or more abnormalities in 50.7% of the joints. On histopathology, osteochondral fragments presented as a bony center covered with smooth hyaline cartilage on one side and some fibrous tissue on the other side. No clear histopathological signs were indicating precisely their origin. In Warmblood horses with dorsoproximal P1 fragments, the age (seven years and older) and the presence of more than one fragment in a fetlock significantly increased the risk of lameness. The osteochondral dorsoproximal P1 fragments could be defined as a developmental orthopaedic disease.

MRI findings of juvenile psoriatic arthritis

The aim of this study was to describe the magnetic resonance imaging (MRI) features of juvenile psoriatic arthritis (JpsA) in children in order to facilitate early diagnosis and proper management. Two pediatric radiologists retrospectively reviewed in consensus a total of 37 abnormal MRI examinations from 31 pediatric patients (nine boys, 22 girls; age range 1-17 years; mean age 9.4 years) who had a definite diagnosis of JpsA and underwent MRI. Each MRI was evaluated for synovium abnormality (thickening and enhancement), joint effusion (small, moderate, and large), bone marrow abnormality (edema, enhancement, and location of abnormality), soft tissue abnormality (edema, enhancement, atrophy, and fatty infiltration), tendon abnormality (thickening, edema, tendon sheath fluid, and enhancement), and articular abnormality (joint space narrowing and erosion). The distribution of abnormal MRI findings among the six categories for the 37 MRI examinations was evaluated. The number of abnormal MRI findings for each MRI examination was assessed. Age at MRI examination and all six categories of abnormal MRI findings according to gender were evaluated. There were a total 96 abnormal MRI findings noted on 37 abnormal MRI examinations from 31 pediatric patients. The 37 abnormal MRI examinations included MRI of the hand (n = 8), knee (n = 8), ankle (n = 5), pelvis (n = 5), temporomandibular joint (n = 4), wrist (n = 3), foot (n = 2), elbow (n = 1), and shoulder (n = 1). Twenty-eight diffuse synovial thickening and/or enhancement were the most common MRI abnormality (29.2%). Joint effusion comprised 22 abnormal MRI findings (22.9%). There were 16 abnormal MRI bone marrow edema and/or enhancement findings (16.7%), and in seven (7.3%) the edema involved non-articular sites. Soft tissue abnormality manifested as edema and/or enhancement constituted 14 abnormal MRI findings (14.5%). There were ten MRI abnormalities (10.4%) involving tendons. Articular abnormality seen as joint space narrowing and/or bone erosion comprised six abnormal MRI findings (6.2%). Most MRI examinations had more than one abnormal finding (84%). Age at which MRI examinations were performed was not significantly different between boys and girls. All six categories of abnormal MRI findings were not significantly different between boys and girls. Children with JpsA typically present with more than one abnormal finding on their MRI studies. While synovial abnormality is the most common MR finding in children with JpsA, multi-focal bone marrow edema and enhancement at both articular and non-articular sites are also notable findings in children with JpsA. The rate of articular abnormality is much lower in children with JpsA in comparison to adults with psoriatic arthritis. Our findings suggest that MRI can play a useful role in the diagnosis and ongoing assessment of this uncommon, though important, pediatric rheumatologic disorder.

Osteochondral Fragmentation in the Synovial Pad of the Fetlock in Warmblood Horses

To determine clinical and arthroscopic characteristics associated with fragments in the synovial pad of the fetlock and to characterize their morphology. Retrospective study. Warmblood horses (n=104) with fragment(s) in the synovial pad. Signalment and results of radiographic and clinical examination were collected before surgery. After arthroscopic fragment removal and joint evaluation for synovial and/or cartilage abnormalities, fragments were measured, and evaluated by histopathology. Synovial pad fragments (n=142) were removed from 127 fetlocks. Two older horses had lameness. During arthroscopy, abnormalities were observed in 40 joints (31.5%) and multivariate logistic regression analysis showed a significant correlation between the observed arthroscopic abnormalities and the presence of large fragments (P=.016). Fragments were osteochondral bodies completely surrounded by fibrous tissue. At the edges of the hyaline cartilage cap an underlying fibrous structure was obvious in the extracellular matrix giving it a reactive pattern. Although the impact on lameness was minimal, there was a significant correlation between arthroscopic abnormalities and presence of large synovial pad fragments. On histopathology, these osteochondral fragments are embedded in fibrous tissue and show a reactive pattern. They are not a manifestation of any well-described joint pathology. Large synovial pad fragments in Warmblood horses can be associated with synovial and cartilage abnormalities, but further studies are warranted to determine their origin and clinical importance.

Mri-Based Morphological Predictorsof Spect Positive Facet Arthropathyin Patients With Axial Back Pain

A major barrier to understanding facetogenic low back pain has been the lack of radiographic diagnostic criteria. This study investigates the correlation between radiographic findings on magnetic resonance imaging (MRI) scans and single photon emission computed tomographic (SPECT) scans in patients clinically found to have facetogenic axial back pain. Thirty-one patients with severe axial back pain underwent lumbar MRI and SPECT scans. Two hundred thirty facets were identified and were graded from 1 to 4 using synovial area, size, cartilaginous discontiguity, osteophytic overgrowth, and joint space obliteration. Twenty-nine "hot" joints were identified on SPECT scans. MRI features of 230 lumbar facets were correlated with SPECT results. Four basic morphological patterns were identified on the basis of synovial appearance on MRI scans, light, mottled, narrowed, and obliterated, and formed the basis for the grading 1 to 4, respectively (sensitivity for "hot facet", 0.93). The mottled group had 0.90 specificity (P = 0.0001). Osteophytic overgrowth demonstrated 0.94 specificity (P = 0.0004). Facet hypertrophy was not associated with increased tracer uptake. We identify four types of synovial architecture on T2-weighted MRI scans with overall high sensitivity for predicting SPECT positivity. These four grades likely represent a continuum of facet degeneration, from a normal to obliterated joint. One particular subtype, Grade 2, demonstrated a high specificity for SPECT and synovial fluid increase suggestive of inflammation. Facet hypertrophy was not predictive of bone scan positivity, perhaps suggesting the protective nature of a hypertrophied facet. Synovial abnormalities correlate with SPECT findings and a grading scale is proposed delineating the degeneration of a lumbar facet over time. A subtype of SPECT(+) inflamed joint is proposed. Further studies will be needed to improve our understanding of the natural history of the lumbar facet.

Synovitis: a potential predictive factor of structural progression of medial tibiofemoral knee osteoarthritis – results of a 1 year longitudinal arthroscopic study in 422 patients

To evaluate the prevalence of synovitis in painful medial tibiofemoral knee osteoarthritis (OA) and to evaluate correlation between synovitis and the structural severity and progression of tibiofemoral cartilage damage. Multicenter, longitudinal, 1-year duration. Primary painful knee OA (ACR criteria) of the medial tibiofemoral compartment, with pain of the signal knee on at least 30 days in the past 2 months, medial joint space width > or = 2mm, at least 10% of one cartilage surface of the medial compartment affected by superficial fibrillation or worse at baseline arthroscopy. ARTHROSCOPIC PARAMETERS: Knee arthroscopy under local anesthesia was performed and videorecorded at entry and after 1 year. Medial chondropathy was scored by using Societe Francaise d'Arthroscopie (SFA) score (0-100) and reader's overall assessment (VAS score, 100 mm). Progression of medial chondropathy was defined by a change in SFA and VAS scores over 4.5 and 8.0 mm after 1 year, respectively. Medial perimeniscal synovium was scored as normal (few translucent and slender villi, fine vascular network), reactive (proliferation of opaque villi), or inflammatory (hypervascularization and/or proliferation of hypertrophic and hyperemic villi). Medial chondropathy and synovitis were scored by a single reader blind to chronology of paired videotapes. Four hundred and twenty-two patients were enrolled (mean age: 61 years, females: 59%, body mass index: 31, mean disease duration: 4 years) and completed the 1-year study. Synovial abnormalities were present in 50% of the patients with reactive and inflammatory aspects in 29% and 21% of the patients, respectively. Patients with a reactive or inflammatory medial synovium had a more severe medial chondropathy. The worsening in medial chondropathy after 1 year was statistically more severe in the group of patients with an inflammatory perimeniscal synovial membrane at baseline compared to patients with normal and reactive aspects, with no difference between these two latter groups. The odds ratio for progression in VAS score after 1 year was 3.11 (95% CI [1.07, 5.69]) for patients with inflammatory synovium at baseline compared to patients with normal synovium. This study suggests that abnormalities of the medial perimeniscal synovium are a common feature of painful medial knee OA, associated with more severe medial chondropathy. It also suggests that an inflammatory aspect of the medial perimeniscal synovium could be considered as a predictive factor of subsequent increased degradation of medial chondropathy.

High-dose chemotherapy and syngeneic stem cell transplantation in a patient with refractory rheumatoid arthritis: poor response associated with persistence of synovial abnormalities

High-dose chemotherapy and syngeneic stem cell transplantation in a patient with refractory rheumatoid arthritis: poor response associated with persistence of synovial abnormalities

Hip arthroscopy: current indications, treatment options, and management issues.

The management of hip injuries in athletes has evolved significantly in the past few years with the advancement of arthroscopic techniques. The application of minimally invasive surgical techniques has facilitated relatively rapid returns to sporting activity in both recreational and elite athletes. Recent advancements in both hip arthroscopy and magnetic resonance imaging have elucidated several sources of intraarticular abnormalities that result in chronic and disabling hip symptoms. Many of these conditions were previously unrecognized and, thus, left untreated. Current indications for hip arthroscopy include the presence of symptomatic acetabular labral tears, hip capsule laxity and instability, chondral lesions, osteochondritis dissecans, ligamentum teres injuries, snapping hip syndrome, iliopsoas bursitis, and loose bodies (for example, synovial chondromatosis). Less common indications include management of osteonecrosis of the femoral head, bony impingment, synovial abnormalities, crystalline hip arthropathy (gout and pseudogout), infection, and posttraumatic intraarticular debris. In rare cases, hip arthroscopy can be used to temporize the symptoms of mild-to-moderate hip osteoarthritis with associated mechanical symptoms. This article discusses the current clinical and radiographic methods to detect early hip joint disease and the current indications and surgical techniques of hip arthroscopy.

The role of hip arthroscopy in the treatment of synovial disorders and loose bodies.

Arthroscopic surgery of the hip is an evolving procedure that can facilitate the diagnosis and treatment of synovial-based disease. Radiographic studies have not reproducibly identified many of the synovial conditions that can affect the hip, and arthroscopy has provided a means to improved diagnostic accuracy and the ability to treat certain conditions. Arthroscopic intervention has been reported in synovial chondromatosis and osteochondromatosis, pigmented villonodular synovitis, inflammatory arthropathies including rheumatoid arthritis, and acute septic arthritis. Patients with other conditions that result in acute and chronic synovitis within the hip such as hemosiderotic synovitis secondary to hemophilia and chondrocalcinosis also may benefit from arthroscopic intervention. These synovial and intraarticular abnormalities have been associated with accelerated joint degeneration, and although the pathologic mechanisms have not been delineated clearly, the clinical description has been advanced using hip arthroscopy. Increased awareness of the association between synovial abnormalities and degeneration has resulted from arthroscopy applied to the hip in early stages of disease and early in the course of symptomatic dysfunction. The indications and treatment capabilities will continue to expand with additional understanding of early hip disease, improvements in equipment, and as outcome studies reveal that the patient benefits from the procedure.

Localized pigmented villonodular synovitis: Arthroscopic diagnosis and management of an “Invisible” lesion

Pigmented villonodular synovitis (PVNS) is a rare disorder that may involve the synovium of joints, bursa, or tendon sheaths. Monoarticular involvement is typical, with the knee most commonly affected. Localized pigmented villonodular synovitis (LPVNS) involves a discrete region of the synovium. Detection and diagnosis of this entity is clinically challenging, and plain radiographs are usually unremarkable. Magnetic resonance imaging (MRI) has been reported to be sensitive for the detection of synovial abnormalities and is the imaging modality of choice in suspected cases of LPVNS. When the diagnosis remains in doubt, arthroscopy may be used for direct visualization of synovial pathology, as well as to obtain tissue for histologic analysis. Definitive treatment may also be performed at the time of arthroscopy. We present a case of LPVNS in which a large (4 cm) lesion was not apparent on preoperative radiographs or MRI and was also missed on initial diagnostic arthroscopy.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 6 (July-August), 2002: pp E31–E31