Introduction: Pigmented villonodular synovitis is an uncommon, benign, proliferative, neoplastic process of the synovial membrane presumed to be of histiocytic origin and is likely to cause diagnostic dilemma. We present 4 cases with varied presentations in the form of increasing groin pain, inguinal mass, co-existing osteoarthritis which were subsequently confirmed to have PVNS. Methods and results: Clinical records and imaging modalities of 4 patients with histologically confirmed Pigmented villonodular synovitis of the hip, accrued from Scottish Bone Tumour Registry between 1969 and 2000 were reviewed. Discussion: PVNS of the hip is an important differential diagnosis when osteoarthritis is associated with atypical clinical picture or lytic lesions. Although it remains confined to the joint, soft tissue masses extending beyond the capsule in to retroperitoneum or anterior and posterior aspects of hip have been reported as shown here. Radiographs in early stages are normal or include a concentric joint space narrowing. MR is an important non-invasive modality for surgical planning and to define the size and extent of the lesion, recurrence, delineating between synovial proliferations and periarticular or intra-abdominal organs. The role of arthroscopy, both diagnostic and therapeutic, is rapidly emerging, although, it has its own limitations. A carefully performed total excision often prevents recurrence as can be seen in this series

Fourteen cases of pigmented villonodular synovitis (PVNS) of the foot and ankle (between January 1957 and December 1999) accrued from Scottish bone tumor registry are presented with an average follow-up of 4.6 years aimed to analyse the clinical, radiological and histopathological features in order to investigate the clinical behaviour of PVNS in the foot and ankle, and to determine the factors influencing recurrence. The mean age was 26.4 years (range, 8 to 52 years). There were eight females and six males. The mean delay in presentation was 10.3 months. The anatomical sites were foot phalanges (n=2), tarso-metatarsal area (n=3) and hindfoot (n=9). Hindfoot cases comprised of 6 extra-articular soft tissue swelling around the ankle, two affecting the ankle joint and one involving the subtalar joint. There were eight (57.1%) cases presented with painless lump, five (35.7%) patients with painful lumps and one case with a lump associated with toe deformity. The clinical suspicion were ganglion, gout, soft tissue swelling (? tumour) and exostosis. Peri-articular tissue invasion and cortical infiltration was found in one third on plain films. CT scan showed multiple lytic lesions and MRI scan findings were consistent with extensive low signal soft tissue hypertrophy and bone erosion, two of which were suspected with synovial sarcoma. Excision of the lump was done in 4 cases with a complete recovery. Foot phalangeal PVNS were treated with toe amputation through metatarsophalangeal joint and no cases had recurrence of the lesion. There were two recurrences affecting the ankle and the subtalar joint. Recurrent ankle PVNS was treated with re-exploration, open synovectomy, curettage of talar cyst and autogenous bone grafting. The second recurrent case involving subtalar joint was treated with re-excision and curettage. Both recurred cases were primarily treated with intralesional excision for their diffuse variety. There were no recurrences in the nodular variety. Complete recovery was achieved in 85.7% case (12/14). A high index of suspicion for PVNS should be observed for cases presenting with a painless or painful mass in the foot and ankle region. Complete recovery can be achieved in the majority by complete excision. Toe amputation may be considered for foot phalangeal PVNS

After knee replacement, therapy resistant, chronic synovitis is common and leads to effusion and pain.

A cohort of 55 patients with 57 knee replacements and chronic synovitis underwent radiosynoviorthesis. In summary, 101 joints were treated using 182±9 MBq of 90Y-citrate. The number of radiosynoviorthesis ranged from 1 to 4 (53%, 21%, 23%, and 4%). Every patient received a 99mTc-MDP scintigraphy before and three months after every radiosynoviorthesis. Follow-up ranged from 5.7 to 86.7 months. For qualitative analysis, an four steps scoring was used (0 = no response or worsening, 1 = slight, 2 = good, 3 = excellent response). For quantification, the uptake was determined within the 99mTc-MDP scintigraphy soft tissue phase before and after therapy.

At the end of long-term follow-up 27% of patients have an excellent, 24% good, 30% slight and 20% no response. The duration of response was 7.5±8.3 months (maximum 27 months). In repeated treatment, the effect after the first therapy was lesser than in patients who received a single treatment in total. However, three months after the last radiosynoviorthesis, patients with repeated treatment showed a similar effectiveness than single treated patients. At the end of long-term follow-up, patients with repeated radiosynoviorthesis had a higher effectiveness at similar duration response. In the 99mTc-MDP scan 65% of patients showed a reduction of uptake. When comparing subjective and objective response 78% of patients showed a concordance in both, symptoms and scintigraphy. Pilot histological analysis revealed that the synovitis is triggered by small plastic particles.

Radiosynoviorthesis is effective in patients with knee replacement and chronic synovitis. It shows good subjective and objective response rates and long response duration. Repeated treatment leads to a stronger long-time response. The chronic synovitis is caused by plastic particles, which result from the abrasion of the polymeric inlay of endoprothesis.

Introduction:. Pigmented Villonodular Synovitis (PVNS) is a rare inflammatory disorder of the synovium, bursa and tendon sheath. The objective of this study was to evaluate the long-term outcomes and morbidity associated with operative management of PVNS of the hand. Methods:. Histological databases were retrospectively interrogated. All patients between 2003–2008 with confirmed PVNS of the hand were included in the study. Results:. 15 patients were identified with PVNS of the hand. 10/15 (67%) patients had growths over the digits and 4/15 (26%) involved the thumb with two of these involving the IPJ. 6/10 (60%) of cases with digital involvement arose from a joint (4 PIPJ & 2 MCPJ). Nodular growth was the most common cause for referral. Average length of symptoms prior to presentation was 2.4 years (6 months–5 years). 6/15(40%) of cases had pre-operative MR scans with 100% radiological and histological correlation. Marginal excision was the operative intervention of choice. There was no evidence of bony destruction in any cases. 4/15(26.7%) patients developed a temporary neurapraxia. 4/15 (26.7%) had recurrence at 5 years of which 3/10 had amputations p=0.008. One amputation was due to digital artery injury, two due to recurrence. All patients reported stiffness post-operatively. No functional deficit was recorded. Conclusions:. MR imaging is useful in radiological confirmation of PVNS and is both sensitive and specific making routine biopsy unnecessary. PVNS joint destruction appears rare in such patients although excision carries a high morbidity and risk of recurrence. Those with recurrence are significantly more likely to undergo amputation

Synovitis in the subacromial bursa (SAB) and the gle-nohumeral joint (GHJ) is often seen in rotator cuff diseases. In order to clarify its significance, following studies were conducted. The mRNA expression levels of IL-1B, sIL-1ra and icIL-1ra and the amount of substance P in the SAB synovium were correlated with the degree of shoulder pain. The cytokine-mRNAs in the GHJ synovium expressed more significantly in full-thickness tears (perforating tears) than in non-perforating tears. Biochemical markers (MMP-1, MMP-3) in the GHJ fluid were significantly higher in massive cuff tears than in smaller tears. These findings suggest the possibility that SAB and GHJ synovitis in rotator cuff diseases are associated with shoulder pain and the development of glenohumeral arthropathy, respectively

Objectives. This study aimed to examine the effects of SRT1720, a potent SIRT1 activator, on osteoarthritis (OA) progression using an experimental OA model. Methods. Osteoarthritis was surgically induced by destabilization of the medial meniscus in eight-week-old C57BL/6 male mice. SRT1720 was administered intraperitoneally twice a week after surgery. Osteoarthritis progression was evaluated histologically using the Osteoarthritis Research Society International (OARSI) score at four, eight, 12 and 16 weeks. The expression of SIRT1, matrix metalloproteinase 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), cleaved caspase-3, PARP p85, and acetylated nuclear factor (NF)-κB p65 in cartilage was examined by immunohistochemistry. Synovitis was also evaluated histologically. Primary mouse epiphyseal chondrocytes were treated with SRT1720 in the presence or absence of interleukin 1 beta (IL-1β), and gene expression changes were examined by real-time polymerase chain reaction (PCR). Results. The OARSI score was significantly lower in mice treated with SRT1720 than in control mice at eight and 12 weeks associated with the decreased size of osteophytes at four and eight weeks. The delayed OA progression in the mice treated with SRT1720 was also associated with increased SIRT1-positive chondrocytes and decreased MMP-13-, ADAMTS-5-, cleaved caspase-3-, PARP p85-, and acetylated NF-κB p65-positive chondrocytes and decreased synovitis at four and eight weeks. SRT1720 treatment partially rescued the decreases in collagen type II alpha 1 (COL2A1) and aggrecan caused by IL-1β, while also reducing the induction of MMP-13 by IL-1β in vitro. Conclusion. The intraperitoneal injection of SRT1720 attenuated experimental OA progression in mice, indicating that SRT1720 could be a new therapeutic approach for OA. Cite this article: K. Nishida, T. Matsushita, K. Takayama, T. Tanaka, N. Miyaji, K. Ibaraki, D. Araki, N. Kanzaki, T. Matsumoto, R. Kuroda. Intraperitoneal injection of the SIRT1 activator SRT1720 attenuates the progression of experimental osteoarthritis in mice. Bone Joint Res 2018;7:252–262. DOI: 10.1302/2046-3758.73.BJR-2017-0227.R1

Pigmented villonodular synovitis is a monoarticular proliferative process most commonly involving the synovium of the knee joint. There is considerable debate with regards to diagnosis and effective treatment. We present our experience of managing PVNS of the knee joint over a 12 year period. Twenty-eight patients were reviewed. MRI was used to establish recurrence in symptomatic patients rather than routine screening and to identify posterior disease prior to surgery. Eight patients had localised disease and were all treated with open synovectomy and excision of the lesion, with no evidence of recurrence. Twenty patients had diffuse disease, eight treated arthroscopically and twelve with open total synovectomy. Nineteen patients (95%) had recurrence on MRI, however, only five (25%) had evidence of clinical recurrence. There were no significant complications following arthroscopic synovectomy. Open synovectomy, in contrast, was associated with three wound infections and two thrombo-embolisms. Three patients had Complex regional pain syndrome. We believe diffuse disease should be treated with arthroscopic synovectomy which is associated with minimal morbidity and can be repeated to maintain disease control. Radiotherapy is helpful in very aggressive cases. TKR was used when there was associated articular erosion

Purpose: Pigmented Villonodular Synovitis (PVNS) is an uncommon presentation characterised by hyperplastic synovium, bloody effusions and bone erosions. Incompletely resected localised and diffuse lesions have a high recurrence rate. The management of recurrent lesions depends on the expertise of the surgeon and severity of the lesion. The imaging characteristics of PVNS and experience of British knee surgeons in managing these lesions is presented in our study. Methods: A postal questionnaire was sent to 100 knee surgeons of the British Association of Surgeons of the Knee (BASK) with questions relating to their experience in managing localised and recurrent PVNS. The options included either arthroscopic or open synovectomy with or without radiotherapy, radical excision or referral. Results: 74 responses were included in the study. 73 out of the total cohort of 74 surgeons (98.7%) had seen less than 5 presentations in their career. Localised lesions were treated primarily by arthroscopic synovectomy [N=58(78.4%)] or open synovectomy [N=12(16.2%)] with radiotherapy being utilised in 4 lesions (5.4%). For local recurrence the management was arthroscopic [N=26(35.1%)] and open [N= 19(25.7%)] synovectomy. Radiotherapy was used in 18 (24.3%) of patients with localised recurrence and 8 (10.8%) of were referred to specialist units. Infiltrating lesions were treated with open synovectomy and radiotherapy [N=22(29.7%)] and 20 cases [27.02%] were referred to specialist units. Imaging of PVNS and Conclusions: The role of imaging is invaluable in early diagnosis and treatment due to limited experience in managing such presentations. Routine radiography and Computerised Axial Tomography (CT scan) often demonstrate non-marginal pressure erosions with sclerotic margins as well as nodular soft tissue masses. Sonography shows non-specific focal or nodular synovial thickening with increased flow on colour doppler. Magnetic Resonance imaging characteristics of PVNS are nodular, synovial masses which are low signal on T1-weighted and T2-weighted imaging

Background: The surgical treatment of extensive diffuse Pigmented Villonodular Synovitis (PVNS) of large joints alone, is unsatisfactory, with high rates of local recurrence. Postsynovectomy adjuvant treatment with external beam radiation therapy or intraarticular injection of Yttrium90 (Y90) yielded better results. Aims: Experience with 10 cases treated with debulking surgery followed by intraarticular injection of Y90 is reported. Methods: Between January 1989 and June 1998, 10 patients (8 males and 2 females aged 15049 years) with extensive diffuse PVNS were treated. In 6 patients the knee joint, in 3 patients the ankle joint, and in 1 patient the hip joint were involved. The 10 patients underwent 15 operations, 1 patient had 3 surgical procedures, and 3 patients underwent 2 surgeries (interval between re-operations for local recurrence were 2–4 years). All patients had an intraarticular injection of 15–25 mCi of Y90, 6–8 weeks after the last surgery. Results: Follow up time was 2.5–12 years (mean 6 years). All patients were followed by repeated computerized tomography (CT) scans, magnetic resonance imaging (MRI), plain X-ray films and bone scans semi-annually. In 9 patients no evidence of disease and no progression of bone or articular destruction have been noted. In 1 patient stabilization of disease was achieved with no further evidence of bony or articular damage. No complications were noticed after surgery, nor after the intraarticular Y90 injection. Conclusions: A combination of debulking surgery with intraarticular injection of Y90 for extensive diffuse PVNS of major joints is a reliable way of treatment with good results

The opposable thumb is one of the defining characteristics of human anatomy and is involved in most activities of daily life. Lack of optimal thumb motion results in pain, weakness, and decrease in quality of life. First carpometacarpal (CMC1) osteoarthritis (OA) is one of the most common sites of OA. Current clinical diagnosis and monitoring of CMC1 OA disease are primarily aided by X-ray radiography; however, many studies have reported discrepancies between radiographic evidence of CMC1 OA and patient-related outcomes of pain and disability. Radiographs lack soft-tissue contrast and are insufficient for the detection of early characteristics of OA such as synovitis, which play a key role in CMC OA disease progression. Magnetic resonance imaging (MRI) and two-dimensional ultrasound (2D-US) are alternative options that are excellent for imaging soft tissue pathology. However, MRI has high operating costs and long wait-times, while 2D-US is highly operator dependent and provides 2D images of 3D anatomical structures. Three-dimensional ultrasound imaging may be an option to address the clinical need for a rapid and safe point of care imaging device. The purpose of this research project is to validate the use of mechanically translated 3D-US in CMC OA patients to assess the measurement capabilities of the device in a clinically diverse population in comparison to MRI.

Four CMC1-OA patients were scanned using the 3D-US device, which was attached to a Canon Aplio i700 US machine with a 14L5 linear transducer with a 10MHz operating frequency and 58mm. Complimentary MR images were acquired using a 3.0 T MRI system and LT 3D coronal photon dense cube fat suppression sequence was used. The volume of the synovium was segmented from both 3D-US and MR images by two raters and the measured volumes were compared to find volume percent differences. Paired sample t-test were used to determine any statistically significant differences between the volumetric measurements observed by the raters and in the measurements found using MRI vs. 3D-US. Interclass Correlation Coefficients were used to determine inter- and intra-rater reliability.

The mean volume percent difference observed between the two raters for the 3D-US and MRI acquired synovial volumes was 1.77% and 4.76%, respectively. The smallest percent difference in volume found between raters was 0.91% and was from an MR image. A paired sample t-test demonstrated that there was no significant difference between the volumetric values observed between MRI and 3D-US. ICC values of 0.99 and 0.98 for 3D-US and MRI respectively, indicate that there was excellent inter-rater reliability between the two raters.

A novel application of a 3D-US acquisition device was evaluated using a CMC OA patient population to determine its clinical feasibility and measurement capabilities in comparison to MRI. As this device is compatible with any commercially available ultrasound machine, it increases its accessibility and ease of use, while proving a method for overcoming some of the limitations associated with radiography, MRI, and 2DUS. 3DUS has the potential to provide clinicians with a tool to quantitatively measure and monitor OA progression at the patient's bedside.

Introduction: Diffused pigmented villonodular synovitis (PVNS) is a locally aggressive lesion for which surgery provides only marginal resection. An adjuvant treatment modality is therefore required to prevent local tumor recurrence. The authors describe their experience with intra-articular injection of Yttrium. 90. (Y. 90. ), a radioisotope, as an adjuvant for tumor resection. Materials and Methods: Between 1989 and 2002, 20 patients with diffuse PVNS were treated with post-operative, intraarticular injection of Y. 90. There were 15 male and 5 female patients who ranged in age from 13 to 67 years (mean, 35 years). Anatomic locations of the affected joints included: knee – 15, ankle – 4, hip – 1. Tumor resection was initially done in all patients: 13 patients required open arthrotomy, the remaining 7 underwent arthroscopic tumor resection. Ten patients were referred for treatment after having operation for a local tumor recurrence: 6 patients had one, 2 had two, 1 had three, and the remaining one had five local recurrences. Six to eight weeks after surgery, intraarticular injection of 15–25 mCi of Y. 90. was done. These procedures were conducted in the operating room under local anesthesia and fluoroscopic guidance. All patients were followed for a minimum of two years (range, 25–168 months; mean, 65 months). Results: Following Y. 90. injection, all patients reported mild pain around the affected joint. This pain was well controlled with the use of NSAID’s and typically resolved within a few days or weeks. Three patients had superficial skin inflammation and associated blisters around the site of injection, probably the result of Y. 90. effect on the soft-tissues. All were treated conservatively with complete resolution of their symptoms. All patients gained their pre-injection range-of-motion within 4–6 weeks. At the most recent follow-up, five patients had transient post-radiation skin changes (discoloration of the skin and dry and scaly skin) and local recurrence occurred in only one patient (5%) with PVNS around the knee; additional Y. 90. injections were unsuccessful and he eventually underwent knee arthrodesis. Conclusion: Y. 90. injection is a reliable adjuvant for surgery in the management of diffused PVNS. Local tumor control and good function, associated with only mild morbidity are achieved in the majority of the patients

Aims

This study aimed to investigate the role and mechanism of meniscal cell lysate (MCL) in fibroblast-like synoviocytes (FLSs) and osteoarthritis (OA).

Aims

This study aimed to define the histopathology of degenerated humeral head cartilage and synovial inflammation of the glenohumeral joint in patients with omarthrosis (OmA) and cuff tear arthropathy (CTA). Additionally, the potential of immunohistochemical tissue biomarkers in reflecting the degeneration status of humeral head cartilage was evaluated.

Abstract

Purpose: Villonodular synovitis is a highly proteiform disease. The classical localisation is in the hand joints, but we focused on pseudomalignant forms which must be recognised to avoid unnecessarily aggressive treatment.

Material and methods: This series included ten files of patients seen for soft tissue tumour of the knee (n=6) or the hip (n=4). Time from first clinical sign to first consultation was two years on the average. The clinical presentation was dominated by major tumefaction of the soft tissues in all patients. There were no signs of joint disease in about half the patients. Radiological signs were noted in six patients. When obtained, MRI demonstrated, in all cases, a tumour formation with ferric deposits and thus contributed considerably to diagnosis.

Results: All patients underwent surgery. Five developed recurrence, as many as four times. One of these recurrent episodes was noted 17 years after the initial intervention that was considered satisfactory (wide monobloc resection). Joint involvement was minimal in these patients with a strong discordance between the minimally troublesome clinical presentation and the major anatomic modifications revealed radiographically.

Discussion: The risk of misdiagnosis is illustrated in our series which included two patients proposed for amputation with one which was actually performed due to a doubtful diagnosis of synovialosarcoma. This observation points out the review of the Swedish registry of synovialosarcomas: of the 81 files enrolled in the registry, 12 were found to be an aggressive form of villonodular synovitis.

Conclusion: The diagnosis of synovialosarcome, considered in patients who present with major tumefaction of soft tissues, signs of joint involvement, or ferric deposits identified on the MRI, should be evaluated with excessive care to rule out possible villonodular synovitis which responds to minimally aggressive treatment to be adapted to each individual case.

Introduction: Substitution treatment and radiosynoviorthesis has a leading role in preventing irreversible hemophilic arthropaties. Aim: The aim of the study is to evaluate the effects of radiosynovectomy on the length of intervals between subsequent bleedings in patients with hemophilic synovitis.

Materials and Methods: 33 joints were treated with radiosynovectomy in 28 patients with bleeding disorders. 90Y colloid was used in knees and 186Re colloid for elbow, shoulder and ankle. 20 patients were on prophylaxis. X-rays of treated joints were evaluated on Peterson scale between 0 (normal) and 13 (severe joint destruction). In observation period (range 6 – 44 months) bleeding episodes were recorded and data statistically analyzed.

Results: Before RS, the average interval between haemorrhages was 16.4 days. Immediately after RS, the average interval between haemorrhages more than tripled. Namely, the average length of the first non-bleeding interval after RS was almost 60 days. In the period covering the first five bleeding episodes after RS, the average non-bleeding interval increased to 47.1 days. Therapeutic effects of RS considerably depend on location (joint) of bleeding, damage of the joint and of the patient. But controlling for location and damage of the joint and age of the patient, after RS every sub sequent non-bleeding interval was 11% shorter (p=0.05) than previous non-bleeding interval. After more than 10 bleeding episodes had occurred since RS, the non-bleeding intervals were no longer significantly shorter than before RS (at p=0.05). Therapeutic response to RS could be, therefore, observed in the period of more than 430 days after the procedure.

Conclusion: Radiosynovectomy significantly reduces hemorrhages in target joints for the average period of 14 months. It is more efficient in patients with less affected joints and less efficient in younger patients. The therapeutic effect of RS diminished with the elapse of time.

The history of synoviorthesis in haemophiliacs and recent studies has shown that it is a safe procedure and that the results are similar to those seen following open or arthroscopic synovectomy. Colloidal Yt 90 silicate is a beta emitter with a half life of 2.7 days and a mean depth of penetrating soft tissue of 4mm. We evaluate the outcome of Yt 90 injection in patients with chronic haemophilic synovitis of the knee.

A retrospective study was done from 1998–2006 of 35 patients with 44 joint injections. Indications were repeated bleeds (4 episodes); chronic synovitis. The age range was 4–27 years. A dose of 2–5 mCu was injected intra-articularly using a sterile technique and local anaesthetic, after an intravenous factor V111 infusion (5 patients had antibodies) and initial joint lavage. The knees were immobilized in above knee backslabs for 2/7. Patient follow up of up to 8 years was conducted. Patients were assessed for pain relief, range of movement, repeated bleeds, cost saving, quality of life and progression to haemophilic arthropathy.

Pain relief of 2 or more points on VAS was reported by 30 patients (85.7%). 18 Patients reported a decrease in bleeding frequency (51.4%). 11 Patients had no further bleeds (31.4%).

We conclude that there was a significant cost saving as a result of the decreased need for the use of cryo-precipitate. Two patients experienced localised areas of necrosis from radio colloid extravasation. These wounds healed after 3 weeks of local dressings. 60% of joints had and increased range of movement. 92% reported improved quality of life.

We have found yttrium synoviorthesis to be an inexpensive, relatively simple and painless technique for treating chronic haemophilic synovitis. The majority of patients were satisfied, experiencing pain relief, increased range of motion and significant monetary saving from reduced cryoprecipitate use.

A patient in his thirties developed synovitis with grade 4 chondrolysis and a stiff knee with a fixed flexion deformity between three and six years following PLC and PCL reconstruction using LARS (Ligament Augmentation and Reconstruction System, Corin). There was histologic evidence of foreign body reaction, the knee was painful, swollen and stiff.

We did not use any further LARS ligaments for soft tissue reconstructions of the kneein our practice. We commenced a recall programme for all 83 patients patients who underwent a soft tissue knee reconstruction using LARS. Of those contacted, 41 replied (49%) and 16 patients had symptoms (19%) and were investigated further with XRay, MRI and arthroscopy as indicated.

We discovered a total of five patients had histologically proven synovitis with foreign body reactions (6%), three of whom had life-changing symptomatic pain, swelling and stiffness with degenerate changes (3.6%). These patients had undergone various reconstructions, including a) PLC only, b) ACL and PCL, c) PCL and PLC and d) ACL, PCL and PLC. A further single case of massive bone cyst formation was noted, following PCL reconstruction using LARS (1.2%).

Background: The role of polyethylene (PE) wear in relation to synovitis and elevated hydrostatic pressure in the loosening process after THA has gained increased attention. The aim of our study was to investigate the correlation between prosthetic head size, PE wear and sonographic capsular distention, reflecting the degree of intracapsular synovitis/synovia/hydrostatic pressure.

Patients and methods: In 2005 we analyzed 60 randomly selected and unrevised OA patients 10 years after surgery with 32 or 28mm femoral heads. We evaluated radiographic signs of loosening, linear and volumetric PE wear. Sonographic examination was performed to measure the “capsular distance”, i.e. the capsular distension, defined as the distance between the metallic echo from the anterior surface of the prosthetic femoral neck, and the echo from the anterior surface of the anterior capsule.

Results: The linear wear was 0.2 mm per year and 0.1 mm per year in the 32 mm and 28 mm head size group respectively (p< 0.001), the volumetric wear was 139 mm3/year and 48 mm3/year (p< 0.001), and the capsular distention was 17 mm and 13 mm respectively (p< 0.001). There was also a significant positive correlation between PE volumetric wear and capsular distension (r=0.63, p< 0.001).

Interpretation: We conclude that 32 mm femoral heads were associated with almost three times higher volumetric wear as compared to 28 mm heads, and increased “capsular distension”, reflecting increased synovitis/synovia/hydrostatic pressure in prosthetic hip.

Purpose of the study: It is relatively rare to observe villonodular synovitis in children. The predominant localization is in the large joints. Histology is required for definitive diagnosis but specific sequences of magnetic resonance imaging (MRI) has greatly improved diagnostic performance.

Material ad methods: we report four cases of hemopigmented villonodular synovitis observed in four girls aged 11–16 years (mean age 12 years) at diagnosis. Localizations were the knee joint in two, the metacarpophalangeal joint of the third finger in one and an intracarpal joint with scaphoid defects in the fourth. Plain x-rays centered on the joint involved and MRI spin echo T1 and T2 with fat saturation were obtained for all four children. Echo gradient with long TE sequences were also performed for the last two children because of the anomalies observed in the first two.

Results: The MRI findings enabled the diagnosis of hemopigmented villonocular synovitis in all four patients and was confirmed histologically (two biopsy specimens followed by dissection and two first-intention dissection specimens).

Discussion: The large joint localizations are often reported but the two cases involving the wrist and fingers are less common. The condition is usually revealed by repeated joint effusion which if punctured generally reveals a hematic discharge. Pain is classical and a mass is often palpated. Standard x-rays show intraosseous defects and MRI, using the three sequences together, generally provides the diagnosis. On the spin echo T1 sequence the synovial mass gives an intermediate signal compared with the low intensity signal of the joint fluid since the cholesterol deposits enhance the signal. In spin echo T2 sequence with fat saturation, the lesion produces a heterogeneous signal which is still intermediary because of the hemosiderin and cholesterol deposits which decrease the inflammatory aspect of the synovitis. These signs are highly suggestive and should be followed by an echo gradient long TE sequence. This is not a routine sequence but provides objective evidence of hyposignals within the synovial mass. This type of signal is specific for the presence of iron and thus hemosiderin.

Conclusion: MRI is the exploration of choice for the diagnosis of hemopigmented villonodular synovitis. It enables postoperative monitoring in search of recurrence.