What is the natural history of asymptomatic pseudotumours in metal-on-metal hip resurfacing patients?

PURPOSE: We assessed the natural history of asymptomatic pseudotumours associated with metal-on-metal hip resurfacings (MoMHRs), and factors associated with future revision. METHODS: In 2007-2008, we identified 25 MoMHRs (21 patients; mean age 59.9 years; 76% female) with asymptomatic pseudotumours. All patients underwent identical initial assessment (ultrasound, blood metal ions, radiographs, Oxford Hip Score [OHS]) and were considered asymptomatic because they denied experiencing hip symptoms, were satisfied with their MoMHR surgery, and had good or excellent OHSs (≥34). In 2012-2013, repeat assessments were performed in all non-revised patients. RESULTS: Revision for pseudotumour was performed/recommended in 15 MoMHRs (60%) at a mean 2.7 years (range 0.4-6.4 years) from initial assessment, with 14 developing symptoms before revision. Non-revised MoMHRs (n = 10) underwent repeat ultrasound at a mean 5.1 years (range 4.0-6.5 years) later, with no changes in pseudotumour volume (p = 0.956) or OHS (p = 0.065) between assessments. High blood cobalt (p = 0.0048) and chromium (p = 0.0162), large pseudotumours (p = 0.0458), low OHS (p = 0.0183), and bilateral MoMHRs (p = 0.049) predicted future revision. Patients with blood metal ions above established unilateral/bilateral thresholds and/or initial pseudotumours >30 cm3 had an 86.7% sensitivity, 70.0% specificity, 81.2% positive predictive value, and 77.8% negative predictive value for future revision. CONCLUSIONS: MoMHR patients with initially asymptomatic pseudotumours often become symptomatic and require revision. Patients with high blood metal ions and/or pseudotumours >30 cm3 should remain under annual surveillance or be considered for revision (especially in patients also having lower initial OHSs, bilateral MoMHRs, and/or those becoming symptomatic). Less regular surveillance of patients outside these parameters appears acceptable.

How Should We Follow-Up Asymptomatic Metal-on-Metal Hip Resurfacing Patients? A Prospective Longitudinal Cohort Study.

Current surveillance for metal-on-metal hip resurfacing (MoMHR) patients is not evidence based. This study established changes that occurred in 152 asymptomatic MoMHRs using repeat ultrasound and patient-reported outcomes. Factors associated with (1) ultrasound progression and (2) developing new pseudotumors were analyzed. Patients underwent repeat assessments 4.3 years later. Ultrasound progression was observed in 19% (n = 29), with 10% (n = 15) developing new pseudotumors. Key predictors of ultrasound progression included high blood cobalt (P = .00013) and chromium (P = .00065), and high initial ultrasound grade (P = .003) and volume (P = .036). No asymptomatic MoMHRs with initially normal metal ions (<2 µg/L) and normal ultrasounds (33% of cohort) developed new pseudotumors. This patient subgroup does not require repeat follow-up within 5 years.

Arthritis at the shoulder joint.

The shoulder is a complex joint with numerous structures contributing to mobility and stability. Shoulder pain is a common clinical complaint that may be due to a wide spectrum of disorders including rotator cuff disease, instability, and arthropathy. Primary osteoarthritis of the shoulder joint is uncommon because it is a non-weight-bearing joint. Significant osteoarthritis of the glenohumeral joint is unusual in the absence of trauma, and the detection of advanced degenerative changes in patients without a known history of trauma should alert the clinician to search for other disorders. This article reviews the pathogenesis, clinical manifestations, and key imaging findings of the common categories of the arthritis affecting the glenohumeral joint.

The extensor mechanism of the knee.

Disorders related to the knee extensor mechanism are common and rarely require imaging. Non specific anterior knee pain, fracture, dislocation, overuse tendinopathy and chronic patellofemoral instability are the commonest conditions encountered. Imaging is used in acute trauma, and for the assessment of cases of anterior knee pain resistant to conservative measures. The role of the radiograph is now largely restricted to cases of suspected fracture. Ultrasound is the optimum technique for suspected tendon and bursal pathology and MRI is widely used for the assessment of dysplasia and instability of the patellofemoral joint, including acute dislocation.

Localized Ewing sarcoma of the tibia.

Ewing sarcoma (ES) is a high-grade malignant primary round cell tumour of bone in which there is commonly extension into extraosseous soft tissues at the time of diagnosis. This report details the clinical, radiological and pathological features of a case of ES of the tibia in which there was extensive osseous involvement but no infiltration beyond the periosteum into surrounding soft tissue. We also record the findings of one other ES case that exhibited similar behaviour. Both cases were male, involved the tibia and had the characteristic t (11;22) (q24;q12) translocation. No recurrence of tumour or metastasis has been seen in these two cases, both of which have had 6 years follow-up. Our findings indicate that there is heterogeneity in the behaviour of ES and show that localized ES is associated with a good prognosis.

A MRI classification of periprosthetic soft tissue masses (pseudotumours) associated with metal-on-metal resurfacing hip arthroplasty.

OBJECTIVE: Metal-on-metal hip resurfacing arthroplasty (MoMHRA) has become a popular option for young patients requiring hip replacement. A recognised complication is the formation of a symptomatic reactive periprosthetic soft tissue mass (pseudotumour). We present a radiological classification system for these reactive masses, dividing them into three groups: Type I are thin-walled cystic masses (cyst wall <3 mm), Type II are thick-walled cystic masses (cyst wall >3 mm, but less than the diameter of the cystic component) and Type III are predominantly solid masses. MATERIALS AND METHODS: We reviewed all MRI performed over a 4-year period in patients with primary MoMHRA referred to our institution. In all cases the masses were assessed on MRI according to size, anatomical position, signal intensity and involvement of bone, muscle or neighbouring neurovascular bundles. RESULTS: Periprosthetic masses were seen in 33 hips in 17 female (7 bilateral) and 8 male patients (1 bilateral). The Type I lesions were the most common and more likely to be posterior to the hip joint. The Type III masses were significantly larger than the cystic lesions and were more likely to be located anterior to the hip joint. To date 22 patients have undergone revision surgery with conversions to total hip replacement. Severity of symptoms and revision rates were lowest in the Type I group and highest in the Type III group. CONCLUSION: Solid anterior pseudotumours were most likely to have the more severe symptoms and require revision surgery.

Hip resurfacing and pseudotumour.

Metal on metal hip resurfacing has been used widely over the last ten years but there has been recent concern about destructive soft tissue reactions, which have been called pseudotumours by some authors. This has generated considerable controversy. This review explains why pseudotumours occur after resurfacing and how they can be prevented. It also supports the continued use of resurfacing in appropriate patients by appropriately trained surgeons.

Immunophenotypic analysis of glomus coccygeum associated with coccygodynia.

OBJECTIVE: Glomus coccygeum is a glomus body which is found in the pericoccygeal soft tissue. This specialised arteriovenous anastomosis is a non-pathological vestigial structure usually larger than its equivalent in the distal extremities. Its prevalence is uncertain. Glomus coccygeum has been associated with coccygodynia and can cause diagnostic problems to pathologists unfamiliar with this entity. MATERIALS AND METHODS: The presence of a glomus coccygeum was sought in 40 coccygectomy specimens and correlated with clinical, radiological and histological findings. RESULTS: A glomus coccygeum was identified in 13 samples (35%). Glomus cells expressed smooth muscle actin (SMA) and were negative for desmin, S100, cytokeratin and a wide range of vascular markers. Proliferative activity was low. Pre-operative MRI did not identify these tiny lesions, and most patients with coccygodynia did not have a glomus coccygeum. CONCLUSION: Glomus coccygeum is a common microanatomical structure which can be distinguished from glomus and other tumours by its small size, SMA expression and low proliferative activity.

Case report: imaging and surgical treatment of a snapping hip due to ischiofemoral impingement.

An association between hip pain and quadratus femoris MRI abnormality with concurrent narrowing of the ischiofemoral space has been reported in a number of patients to date, raising the possibility that the muscular damage observed is due to ischiofemoral impingement. Possible impingement has been noted primarily in middle-aged females either with or without a history of trauma or surgery, and associated snapping of the hip is a rarely described feature. We report here on a 17-year-old girl who presented with post-traumatic hip pain; she later developed evidence of ischiofemoral narrowing and quadratus femoris edema on MRI in addition to an audible snapping. Surgical resection of the lesser trochanter was performed, relieving both her hip pain and the snapping. To our knowledge, this is the first reported case of non-iatrogenic ischiofemoral impingement with surgical confirmation. The diagnosis of ischiofemoral impingement should be considered in patients complaining of a snapping hip.

Metal-on-metal hip resurfacings--a radiological perspective.

It is important to be aware of the various complications related to resurfacing arthroplasty of the hip (RSA) and the spectrum of findings that may be encountered on imaging. The bone conserving metal-on-metal (MOM) hip resurfacing has become increasingly popular over the last ten years, especially in young and active patients. Initial reports have been encouraging, but long-term outcome is still unknown. Early post operative complications are rare and have been well documented in the literature. Medium and long term complications are less well understood. A rare but important problem seen at this stage is the appearance of a cystic or solid periarticular reactive mass, which occurs predominately in women and usually affects both hips when seen in patients with bilateral RSAs. The following imaging findings are illustrated and their significance discussed; Uncomplicated hip resurfacing arthroplasty, radiolucency around the femoral peg, femoral neck fracture, loosening and infection, suboptimal component position, femoral notching, dislocation, heterotopic ossification, femoral neck thinning and reactive masses. The radiologist should be aware of the normal radiographic appearances and the variety of complications that may occur following RSA and should recommend ultrasound or MRI in patients with an unexplained symptomatic hip and normal radiographs.

"Asymptomatic" pseudotumors after metal-on-metal hip resurfacing arthroplasty: prevalence and metal ion study.

Symptomatic abnormal periprosthetic soft-tissue reactions ("pseudotumors") have been reported after metal-on-metal hip resurfacing arthroplasty (MoMHRA). The aims of this study were (1) to determine the prevalence of asymptomatic pseudotumors after MoMHRA and (2) to measure metal ion levels in these patients. A total of 201 hips in 158 patients were evaluated at a mean follow-up of 61 months (range, 36-88) using ultrasound/magnetic resonance imaging and serum/hip aspirate cobalt and chromium measurements. Pseudotumors found in 7 patients (4%) were associated with significantly higher cobalt and chromium levels and inferior functional scores. Elevated levels of cobalt and chromium ions suggest that pseudotumors are associated with increased wear generated from metal-on-metal articulations. Clinicians need to be aware of pseudotumors as a differential diagnosis during clinical evaluation of MoMHRA patients, and further imaging such as ultrasound or magnetic resonance imaging is recommended to confirm the diagnosis.

Morton's neuroma: diagnostic accuracy, effect on treatment time and costs of direct referral to ultrasound by primary care physicians.

BACKGROUND: The first-line treatment for symptomatic Morton's neuroma in our hospital is a perineural ultrasound-guided injection of corticosteroid and local anaesthetic (USI). The NHS has recently implemented 18-week referral-to-treatment targets. When GPs specifically suggest a diagnosis of Morton's neuroma there are two referral pathways in our hospital: direct referral to radiology for USI (limited slots) or referral to the specialist foot and ankle clinic. Patients with less specific referral letters are also evaluated in clinic and referred for USI as appropriate. METHODS: A retrospective audit was performed reviewing referral letters from general practitioners (GPs) in 2005-2006. A comparison was made between the referral pathways for time-to-treatment (TTT), accuracy of GP diagnosis, and cost implications. RESULTS: In the directly referred group, the median TTT was 99 days, compared to 206 days for patients who went via a foot and ankle clinic (P < 0.001). Of 57 patients with a GP diagnosis of Morton's neuroma, 40 (70%) had the diagnosis confirmed on USI compared to 44 of 64 (69%) patients referred by a foot and ankle surgeon, showing no significant difference between the groups (P = 0.87). CONCLUSION: For patients with features highly suggestive of a Morton's neuroma, direct referral from primary care for USI had a similar accuracy to referral from a specialist hospital clinic and the time-to-treatment was significantly shorter. The mean waiting time of this group was within the 18-week government target without any changes to our current radiology protocols.

The imaging spectrum of peri-articular inflammatory masses following metal-on-metal hip resurfacing.

INTRODUCTION: Resurfacing metal-on-metal hip arthroplasty is increasing in popularity, especially in younger patients. To date, studies indicate that the procedure is associated with a good outcome in the medium-term. Formation of a peri-articuar mass is a rarely reported complication. In this study we analyse the imaging findings in patients with resurfacing implants presenting to our institution with peri-articular masses identified on cross sectional imaging. MATERIALS AND METHODS: All patients with documented peri-articular masses following resurfacing arthroplasty were included. The available imaging related to the masses was reviewed and the findings documented along with the patient's demographics. RESULTS: There were 10 patients (13 joints). All patients were female. Patients presented with periprosthetic anterior or posterolateral solid and cystic masses. The anterior masses involved psoas muscle and were predominately solid. The posterolateral masses were predominately cystic. In the three cases with bilateral arthroplasties, masses were detected in both hips. Histology in six cases showed features compatible with a type IV hypersensitivity reaction. CONCLUSIONS: The preponderance of females, the bilateral nature of the masses and the histological features suggest that peri-articular masses following resurfacing arthroplasty is due to the metal hypersensitivity.

Changes in shoulder muscle size and activity following treatment for breast cancer.

BACKGROUND: Morbidity of the shoulder after breast cancer is a well-known phenomenon. MRI studies have shown muscle morbidity in cervical cancer and prostate cancer. In breast cancer clinical observations and patient reports include muscle morbidity in a number of muscles acting at the shoulder. Several of these muscles lie in the field of surgery and radiotherapy. Timed interaction between muscles that stabilise the shoulder and those acting as prime movers is essential to achieve a smooth scapulohumeral rthythm during functional elevation of the arm. METHOD: CROSS-SECTIONAL STUDY: Seventy-four women treated for unilateral carcinoma of the breast were included in the study. All patients filled out the Shoulder Pain and Disability Index (SPADI). EMG activity of four muscles was recorded during scaption on the affected and unaffected side. Muscle cross sectional area and signal intensity was determined from MRI scans. The association between EMG and covariates was determined using multiple linear regression techniques. RESULTS: Three of the 4 muscles on the affected side demonstrated significantly less EMG activity, particularly when lowering the arm. Upper trapezius demonstrated the greatest loss in activity. Decreased activity in both upper trapezius and rhomboid were significantly associated with an increase in SPADI score and increased time since surgery. Pectoralis major and minor were significantly smaller on the affected side. CONCLUSION: Muscles affected in the long term are the muscles associated with pain and disability yet are not in the direct field of surgery or radiotherapy. Primary muscle shortening and secondary loss of muscle activity may be producing a movement disorder similar to the 'Dropped Shoulder Syndrome'. Exercise programmes should aim not only for range of movement but also for posture correction and education of potential long-term effects.

Dynamic ultrasound as a selection tool for reducing achilles tendon reruptures.

BACKGROUND: The optimal method of treatment for acute tendo-Achilles ruptures continues to be debated. HYPOTHESIS: The reported lower rerupture rate for operatively treated patients is an effect of tendon end apposition during the healing process, and patients in whom apposition can be demonstrated using ultrasound will have a similar rate of rerupture if treated nonoperatively. STUDY DESIGN: Cohort study; Level of evidence, 2. METHOD: The authors reviewed all patients with an Achilles tendon rupture who were treated to a standard protocol during a 5-year period (2000-2005). Patients with a gap of 5 mm or more in equinus on ultrasound underwent surgery; those with a gap of less than 5 mm received nonoperative treatment. All patients were followed up to a minimum of 12 months. RESULTS: After exclusions, 125 patients were included: 67 treated operatively and 58 nonoperatively. There were 2 reruptures in the nonoperative group and 1 with surgery. There was no significant difference between the groups for any complication. CONCLUSION: Reduction of rerupture and surgery risks may be possible using dynamic ultrasound case selection. Further studies are needed to show whether functional results are the same with surgical and nonsurgical treatment when dynamic ultrasound criteria are used for case selection.

Ulnar nerve compression at Guyon's canal by an anomalous abductor digiti minimi muscle: the role of ultrasound in clinical diagnosis.

Anomalous variations of abductor digiti minimi are commonly found at Guyon's canal but rarely cause ulnar nerve compression. We report such a case with particular emphasis on the effectiveness of ultrasound to detect and delineate anatomical structures in this region.