Introduction. Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal bone cyst resection and lower limb reconstruction using cable transport and syndesmosis preservation. Materials & Methods. Case 1 - A 12-year-old boy presented with a two-week history of atraumatic right ankle pain. An X-ray demonstrated a distal tibia metaphyseal cyst confirmed on biopsy as an aneurysmal bone cyst. The cyst expanded on interval X-rays from 5.5cm to 8.5cm in 9 weeks. A wide-margin en-bloc resection was performed leaving a 13.8cm tibial defect. A cable transport hexapod frame and a proximal tibial osteotomy was performed, with syndesmosis screw fixation. The transport phase lasted 11 months. While in frame, the boy sustained a distal femur fracture from a fall. The femur and the docking site were plated at the same sitting and frame removed. At one-year post-frame removal he is pain-free, with full ankle dorsiflexion but plantarflexion limited to 25 degrees. He has begun graduated return to sport. Results. Case 2 - A 12-year-old girl was referred with a three-month history of lateral left ankle swelling. X-ray demonstrated an aneurysmal bone cyst in the distal fibula metaphysis. The cyst grew from 4.2 × 2.3cm to 5.2 × 3.32cm in 2 months. A distal fibula resection (6.2cm) with syndesmosis fixation and hexapod cable transport frame were undertaken. The frame was in situ for 13 weeks and during this time she required an additional osteotomy for premature consolidation and had one pin site infection. After 13 weeks a second syndesmosis screw was placed, frame removed, and a cast applied. 3 months later she had fibular plating, BMAC and autologous iliac crest bone graft for slow union. At 3 years post-operative she has no evidence of recurrence, is pain-free and has no functional limitation. Conclusions. We describe two cases of ankle syndesmosis preservation using cable transport for juxta-articular aneurysmal bone cysts. This allows wide resection to prevent recurrence while also preserving primary ankle stability and leg length in children. Both children had a minor complication, but both had an excellent final outcome. Cable bone transport and prophylactic syndesmosis stabilization allows treatment of challenging juxta-articular aneurysmal bone cysts about the ankle. These techniques are especially useful in large bone defects

Introduction. Comparative studies examining Fixed-Bearing (FB) and Mobile-Bearing (MB) Total Ankle Replacement (TAR) designs have demonstrated similar results and successful long-term outcomes for both. To date there has been no study directly comparing FB and MB designs of the same prosthesis. We present the first prospective randomised trial comparing patient satisfaction, functional outcomes and radiographic results of the Salto Talaris Fixed-Bearing and the Salto Mobile-Bearing Total Ankle Replacement in the treatment of end-stage ankle arthritis. Methods. A total of 108 adult patients with end-stage ankle arthritis were enrolled in the study between November 2014 and October 2021 with similar demographic comparison. Prospective patient-reported outcomes and standardised weightbearing ankle radiographs were performed preoperatively, at 6 weeks, 6 months and 12 months post-operatively, followed by yearly intervals. All surgeries were performed by a single non-design orthopaedic foot and ankle specialist with experience in over 200 Salto and Salto Talaris TAR prior to the study. Radiographs were examined independently by two clinicians. Complete patient data and radiographs were available for 103 patients with an average follow up of 2 years. Results. Both groups demonstrated statistically significant improvement from preoperative evaluation to most recent follow up with no statistically significant difference between the two groups in all outcome measures. Radiographic incidence of subchondral cyst formation was 8.9% and 38.2% for FB and MB, respectively. Talar subsidence occurred in 2.2% and 5.5% of FB and MB, respectively. Discussion. Our study demonstrates a higher than previously reported rate of cyst formation in the MB TAR and comparatively higher talar subsidence in the MB TAR vs FB however this did not correlate with clinical outcome measures which were favourable for both groups. Conclusion. Fixed-Bearing and Mobile-Bearing Total Ankle Replacement demonstrate comparable favourable

As an alternative to total hip arthroplasty (THA), hip resurfacing arthroplasty (HRA) provides the advantage of retaining bone stock. However, femoral component loosening and femoral neck fracture continue to be leading causes of revision in HRA. Surgical technique including cementation method and bone preparation, and patient selection are known to be important for fixation. This study was designed to understand if and to what extent compromise in bone quality and the presence of cysts in the proximal femur contribute to resurfacing component loosening. A finite element (FE) model of a proximal femur was used to calculate the stress in the cement layer. Bone density to Young's modulus relationship was used to calibrate the bone stiffness in the model using computed tomography. A contemporary resurfacing implant (BHR, Smith & Nephew) was used in the FE model. The effect of reduced bone quality (35% reduction relative to normal baseline; osteoporosis threshold) and presence of cysts on stress in the bone cement layer was then assessed using the same FE model. The center of the cyst (a localized spherical cavity 1 cm in diameter) was located directly under the contact patch. Simulations were run with two locations of the center of the cyst, on the surface of the resected bone and 1 cm below it. The surface cyst was filled with bone cement, but the inner cyst was empty. The contact force and location for the model were obtained from instrumented implant studies. Simulations were run representing the peak loads during two activities, jogging and stand-up from seated position. While density reduction of the bone reduced the stress in the CoCr femoral head, the Von-Mises stress in the cement layer was amplified. The peak Von-Mises stress in the cement layer under the contact patch increased more than six times for the jogging activity, and more than ten times for the stand-up activity, relative to values for normal bone density. The impact of cysts on the cement layer stress or the strain distributions in the bone were minimal. The results show a greater risk of failure of the cement layer under conditions of reduced bone density. In contrast cement stresses and bone strains appeared to be relatively immune to a surface cyst filled with bone cement or an empty inner cyst. Contraindications of hip resurfacing include severe osteopenia and multiple cysts of the femoral head, however no strict or quantitative criteria exist to guide patient selection. Research similar to the one presented herein, maybe key to developing better patient selection criteria to reduce risk associated with compromised femoral head fixation

Introduction. Hip arthrodiastasis for paediatric hip conditions such as Perthes disease is growing in popularity. Intended merits include halting the collapse of the femoral head and maintaining sphericity by minimising the joint reaction force. This can also be applied to protecting hip reconstruction following treatment of hip dysplasia. Our aim was to assess functional outcomes and complications in a cohort of paediatric patients. Materials and Methods. A retrospective single-surgeon cohort study was performed in a University teaching hospital from 2018–2021. Follow-up was performed via telephone interview and review of patient records. Complications, time in frame and functional scores using the WOMAC hip score were recorded. Results. Following review, 26 procedures were identified in 24 patients. Indications included 16 cases of Perthes disease, 4 following slipper upper femoral epiphysis, 3 avascular necrosis, and single cases following infection, dysplasia and a bone cyst. Pre-treatment WOMAC scores averaged 53.9, improving to 88.5 post-removal. Pin site infections were encountered in 11 patients, all treated with oral antibiotics. Two patients required early removal of frame due to pin loosening. Average time in frame was 3.9 months. Conclusions. This series displays how hip arthrodiastasis can be used to manage paediatric hip conditions. Complex reconstructions may be required in patients with severe deformity following perthes disease, DDH or SUFE. The use of arthrodiastasis in these patients aims to protect the reconstruction and potentially improve outcomes. A dedicated team of specialist nurses, physiotherapists and psychologists are crucial to the treatment program

Juvenile Osteochondritis dissecans (JOCD) in humans and subchondral cystic lesions (SCL) in horses (also termed radiolucencies) share similarities: they develop in skeletally immature individuals at the same location in the medial femoral condyle (MFC) and their etiology is only partially understood but trauma is suspected to be involved. JOCD is relatively uncommon in people whereas SCLs arise in 6% of young horses leading to lameness. Ischemic chondronecrosis is speculated to have a role in both osteochondrosis and SCL pathogenesis. We hypothesize that MFC radiolucencies develop very early in life following a focal internal trauma to the osteochondral junction. Our aims were to characterize early MFC radioluciencies in foals from 0 to 2 years old. Distal femurs (n=182) from Thoroughbred horses (n=91, 0–2 years old), presented for post-mortem examination for reasons unrelated to this study, were collected. Radiographs and clinical tomodensitometry were performed to identify lesions defined as a focal delay of ossification. Micro-tomodensitometry (m-CT) and histology was then performed on the MFCs (CT lesions and age-matched subset of controls). Images were constructed in 3D. The thawed condyles, following fixation, were sectioned within the region of interest, determined by CT lesion sites. Hematoxylin eosin phloxin and safran (HEPS) and Martius-Scarlet-Blue (MSB) stains were performed. Histological parameters assessed included presence of chondronecrosis, fibrin, fibroplasia and osteochondral fracture. An additional subset of CT control (lesion-free) MFCs (less 6 months old) were studied to identify early chondronecrosis lesions distant from the osteochondral junction. One MFC in clinical CT triages controls had a small lesion on m-CT and was placed in the lesion group. All m-CT and histologic lesions (n=23) had a focal delay of ossification located in the same site, a weight bearing area on craniomedial condyle. The youngest specimen with lesions was less than 2 months old. On m-CT 3D image analysis, the lesions seemed to progressively move in a craniolateral to caudomedial direction with advancing age and development. Seventy-four percent (n=17/23) of the lesions had bone-cartilage separation (considered to be osteochondral fractures) confirmed by the identification of fibrin/clot on MSB stains, representing an acute focal bleed. Fibroplasia, indicating chronicity, was also identified (74%, n=17/23). In four cases, the chondrocytes in the adjacent cartilage were healthy and no chondronecrosis was identified in any sections in the lesions. Nineteen cases had chondronecrosis and always on the surface adjacent to the bone, at the osteochondral junction. None of the subset of control specimens, less than 6 months old (n=44), had chondronecrosis within the growth cartilage. Early subchondral cystic lesions of the medial femoral condyle may arise secondary to focal internal trauma at the osteochondral junction. The presence of fibrin/clot is compatible with a recent focal bleed in the lesion. Medial femorotibial joint internal forces related to geometry could be the cause of repetitive trauma and lesion progression. In the juvenile horse, and potentially humans, the early diagnosis of MFC lesions and rest during the susceptible period may reduce progression and promote healing by prevention of repetitive trauma, but requires further study

Purpose. The traditional management of pediatric aneurysmal bone cysts involves the application of intralesional resection principles that are used to treat benign aggressive tumors in general. Alternatively, some are treated by injections of sclerosing agents. The risks of these approaches include growth arrest, additional bony destruction necessitating the restoration of structural integrity, and soft tissue necrosis. We wished to evaluate the effectiveness of treating aneurysmal bone cysts in children by percutaneous curettage as a means to avoid these risks. Method. A retrospective cohort study of pediatric, histologically proven aneurysmal bone cyst patients treated either by percutaneous curettage or by open intralesional resection with two years follow up was undertaken. Those cysts judged as uncontained and requiring restoration of structural bony integrity underwent open intralesional resection and reconstruction. Contained cysts judged as not requiring immediate structural restoration were treated percutaneously. This group was uniformly treated on an outpatient basis using angled curettes under image guidance followed by intralesional evacuation using a suction trap. None in this group had insertion of any substance into the cyst cavity. Short-term casting or immobilization was undertaken in most cases. The primary outcome evaluated was radiographic resolution, persistence or recurrence at two years according to the Neer/Cole classification. Complications were noted. Results. Twenty patients with a mean age of 11 (2–15) were evaluated, with ten in each group. In the open intralesional resection group, 9/10 achieved Neer/Cole grade I resolution; one case recurred and was successfully treated percutaneously. There was one case of valgus proximal tibial overgrowth deformity requiring hemiepiphysiodesis, and three cases requiring hardware removal for irritation. In the percutaneous group, 7/10 achieved Neer/Cole grade 1 resolution, one case exhibited radiographic persistence of nonexpansile, lytic change and two cases frankly recurred, necessitating repeat procedures. No fractures, growth arrests, or infections occurred in either group. Conclusion. Not all aneurysmal bone cysts require wide exposure for intralesional resection. Percutaneous curettage is a reasonable alternative for contained aneurysmal bone cysts. Children will readily restore bone stock in the absence of bone graft or bone substitute as long as the cyst is erradicated. Percutaneous curettage should be performed selectively and on an investigational basis for the time being

The role of magnetic resonance arthrography (MRA) in the evaluation of patients with femoroacetabular impingement (FAI) to assess femoral head-neck junction asphericity and labral pathology is well established. However, in our experience, the presence of acetabular cysts on MRA, which may signify underlying full thickness articular cartilage delamination and progression towards arthropathy, is also an important feature. We retrospectively reviewed 142 hips (mean age 32 years, 47 men, 95 women), correlating the findings on MRA with those found at the time of open surgical hip debridement to ascertain the prevalence of acetabular cysts and the association with underlying acetabular changes. Fourteen MRAs demonstrated features consistent with underlying acetabular cystic change. At the time of surgery, this was confirmed in eleven cases that demonstrated a full thickness articular chondral flap in all cases and an underlying acetabular cyst. The sensitivity, specificity, positive predictive value and negative predictive value of MRA in relation to acetabular cysts was 55%, 97.5%, 78.5% and 92.9% respectively. We believe acetabular cysts on MRA to be a significant finding. Such patients are likely to have an associated full thickness chondral lesion and features of early degenerative change, influencing outcome and prognosis. Our clinical practice has changed to reflect this finding. For those patients with cysts on MRA, we offer open debridement only to the severely affected young and favour arthroscopic debridement in older patients with smaller cams. We believe hip preservation surgeons should be aware of the significance of acetabular cysts and be prepared to adjust treatment accordingly

The role of magnetic resonance arthrography (MRA) in the evaluation of patients with femeroacetabular impingement (FAI) to assess femoral head-neck junction asphericity and labral pathology is well established. However, in our experience the presence of acetabular cysts on MRA, which may signify underlying full thickness articular cartilage delamination and progression towards arthropathy, is also an important feature. We retrospectively reviewed 142 hips (mean age 32 years, 47 men, 95 women), correlating the findings on MRA with those found at the time of open surgical hip debridement to ascertain the prevalence of acetabular cysts and the association with underlying acetabular changes. Fifteen MRA's demonstrated features consistent with underlying acetabular cystic change. At the time of surgery, this was confirmed in eleven cases that demonstrated a full thickness articular chondral flap (carpet lesion) and an underlying acetabular cyst. The sensitivity, specificity, positive predictive value and negative predictive value of MRA in relation to acetabular cysts was 55%, 96.7%, 73.3% and 92.9% respectively. We believe acetabular cysts on MRA to be a significant finding. Such patients are likely to have an associated full thickness chondral lesion and features of early degenerative change, influencing outcome and prognosis. Our clinical practise has changed to reflect this finding. For those patients with cysts on MRA, we are less likely to offer open debridement and favour arthroscopic intervention followed by arthroplasty when symptoms dictate. We believe hip preservation surgeons should be aware of the significance of acetabular cysts and be prepared to adjust treatment options accordingly

Cobalt-chrome alloys are widely used in dentistry and Orthopaedic implant industry. Vitallium is a similar alloy which contains 60% cobalt, 20% chromium, 5% molybdenum along with traces of other substances. It has been in use along with stainless steel for the last century because of its lightweight, favourable mechanical properties and resistance to corrosion. We present an unusual case of synovial cyst formation following Vitallium plating mimicking a sarcoma. To our knowledge, we are the first to report a delayed tissue reaction to Vitallium plating 40 years after its implantation. A 78 yrs old man had a right femoral intertrochanteric fracture 40 years ago, which was fixed with a Vitallium nail plate. His postoperative recovery was uneventful and he regained full function of his leg. 3 years prior to excision, he presented with a painless swelling around his right upper thigh to our unit. Aspiration of the swelling and investigations were requested but patient was lost to follow up due to social reasons. Seven months prior to excision, he represented as the swelling had increased to the extent that it was involving the anterior and posterior aspect of the upper thigh with pressure necrosis of skin posteriorly. Examination revealed painless, transilluminable, fluctuant multilobular swelling over the right proximal femur overlying the healed surgical scar. Compression of the larger lobe in the buttock clearly forced fluid into the anterior compartment of the thigh where again swelling was extensive. Surprisingly he had full range of movements at the hip joint. Radiograph of the hip showed a soft tissue swelling with a healed fracture and Vitallium implant insitu. Cytology was negative. MRI scan showed multiloculated cystic lesions extending anteriorly, laterally and posteriorly into the intermuscular and subcutaneous planes around the right proximal femur. Multiple small dependent foci likely representing debris or synovial proliferation was seen within loculations. Excision of the cystic lesions with removal of metal work was performed. The old incision was reopened in the lateral position and a large cystic lesion with a thick capsule was dissected down to the metal work. The lesion was lying superficial to the vastus lateralis but was communicating with metal work. The metal work was removed with difficulty, no visible metallosis. A second cystic lesion was located more posteriorly but its neck was communicating with the thin hole into the first lesion. The lesion was excised completely. Macroscopic examination showed two cysts 9×8×5.5cm and 20×10×7.5cm with a smooth external surface and the lumen appeared trabecular containing numerous loose (rice) bodies. Microscopy showed a dense fibrotic cyst wall with lumen with multiple small nodules containing organised fibrinous and eosinophilic material. Several foci of cellular debris including lymphocytes and macrophages were scattered in nodules best representing a synovial cyst with loose/rice bodies. No malignancy was seen. We recommend early removal of metal work if it shows any signs of local reaction provided fracture is united. Be aware of large foreign body/ hypersensitivity reaction and incompatible equipment for removal

Ceramic-on-ceramic bearings provide a solution to the osteolysis seen with traditional metal-on-polyethylene bearings. Sporadic reports of ceramic breakage and squeaking concern some surgeons and this bearing combination can show in vivo signs of edge loading wear which was not predicted from in vitro studies. Taper damage or debris in the taper between the ceramic and metal may lead to breakage of either a ceramic head or insert. Fastidious surgical technique may help to minimise the risk of ceramic breakage. Squeaking is usually a benign complication, most frequently occurring when the hip is fully flexed. Rarely, it can occur with each step of walking when it can be sufficiently troublesome to require revision surgery. The etiology of squeaking is multifactorial in origin. Taller, heavier and younger patients with higher activity levels are more prone to hips that squeak. Cup version and inclination are also relevant factors. Osteolysis following metal-on-UHMW polyethylene Total Hip Arthroplasty (THA) is well reported. Earlier generation ceramic-on-ceramic bearings did produce some osteolysis, but in flawed implants. As third and now fourth generation ceramic THAs come into mid- and long-term service, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. The technique used by radiologists for identifying the nature of lesions on Computed Tomography (CT) scan is the Hounsfield score which will identify the density of the tissue within the lucent area. Commonly the radiologist will have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA, which states there is osteolysis? This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term third generation ceramic-on-ceramic uncemented hip arthroplasties in our department. Pelvic CT scans were performed on the first 27 patients from a cohort of 301 patients undergoing 15-year review with third generation alumina-alumina cementless THAs. The average follow-up was 15 years (15–17). The CT scans were reviewed against pre-operative and post-operative radiographs and reviewed by a second musculoskeletal specialist radiologist. Eleven of the CT scans were reported to show acetabular osteolysis, two reported osteolysis or a possible pre-existing cyst and one reported a definitive pre-existing cyst. After review of previous imaging including pre-operative radiographs, eleven of the thirteen patients initially reported to have osteolysis were found to have pre-existing cysts or geodes in the same size and position as the reported osteolysis, and a further patient had spot-welds with stress-shielding. One patient with evidence of true osteolysis awaits aspiration or biopsy to determine if he has evidence of ceramic wear or metallosis. Reports of osteolysis on CT should be interpreted with care in modern ceramic-on-ceramic THA to prevent unnecessary revision. Further imaging and investigations may be necessary to exclude other conditions such as geodes, or stress shielding which are frequently confused with osteolysis on CT scans

Introduction:. Sinus histiocytosis with massive lymphadenopathy (SHML) also known as Rosai – Dorfman disease is a disease of bone marrow stem cell origin. It affects lymph nodes primarily. Solitary bone lesions are very rare and can cause diagnostic difficulty. Aim:. To increase the awareness of SHML as a cause of cystic bone lesions. Materials and methods:. A 2 year old presented with 4 months history of pain and swelling of the distal forearm. There was no history of tuberculosis or HIV disease. The swelling was 4 × 3 cm firm, non-fluctuant and slightly tender. There were no lymph nodes. Radiographs showed an oval cystic lesion expanding with a well-defined margin. The ulnar cortex was deficient. CT scan confirmed a cystic lesion with contents of granulation tissue. The Hb and WCC were normal, ESR 20 was, CRP<5 and mantoux was negative. At surgery the lesion was curretted. The contents resembled tuberculous granulation but there was no caseation. The borders were well formed, the ulnar cortex was deficient. Results:. The histology revealed granulation tissue with numerous large histiocytes and immuno chemistry confirmed Rosai Dorfman disease. Healing with sclerosis was seen at 6 months. Discussion:. Rosai Dorfman disease is a systemic disease of bone marrow stem cells and lymphadenopathy is the prominent manifestation. Only ±8% of cases have been reported with bone involvement and 4% of these had no lymphadenopathy. The lesions are cystic and medullary but cortical involvement can occur. Solitary ossseous lesions characterized by a background of histocytes without eosinophils can mimic Langerhans histocytosis, localized osteomyelitis, fibrous dysplasia, tuberculosis, simple or aneurysmal bone cysts and metastatic deposits. Conclusion:. Lesions of haematopoetic origin should be considered in the diagnosis of lucent bone lesions in children

Introduction. Pseudotumors have been reported following metal-on-metal total hip arthroplasty (THA); however, the natural history and longitudinal imaging findings of pseudotumors have yet to be fully analyzed. Our hypothesis was that pseudotumor size might change over time following metal-on-metal THA. This hypothesis was studied longitudinally using magnetic resonance imaging (MRI). Materials and Methods. Screening for pseudotumors was performed using MRI after large-diameter metal-on-metal THA. Initial MRI was conducted at a mean of 36 months postoperatively. Follow-up MRI was performed at a mean of 20 months after the detection of 24 pseudotumors in 20 asymptomatic patients. Pseudotumors were classified as cystic, solid, and mixed types. Fourteen hips were characterized as cystic type and 10 hips were defined as mixed type. There were three men and 17 women with a mean age of 63 years. Pseudotumor size was determined on MRI by manually outlining the greatest size of the mass. Serum cobalt and chromium ion levels were measured in nine patients with unilateral THA at the time of MRI. Statistical analysis was performed using the Kruskal-Wallis test and chi square test to compare age, gender, BMI, head diameter, cup inclination, cup anteversion, and pseudotumor type among changes of pseudotumor size. We compared the pseudotumor size for the three groups (increase in size, no change, decrease in size) using Kruskal-Wallis test and Mann-Whitney U test. Wilcoxon signed-rank test was used to compare median serum metal ion levels over time. A p value < 0.05 was considered significant. This study was approved by the ethics committee of our institution, and all patients provided informed consent. Results. The mean pseudotumor size changed from 729 mm. 2. to 877 mm. 2. Among the 24 hips, pseudotumors increased in size (Fig. 1) in eight (three cystic and five mixed) and decreased in size in six (four cystic and two mixed). Ten hips showed no changes in size (seven cystic and three mixed). We found no significant differences between changes of pseudotumor size and patient characteristics. The mean initial size of pseudotumor was bigger in pseudotumors with increased in size (1002 ± 309 mm. 2. ) than in those with decreased in size (542 ± 295 mm. 2. , p = 0.020) or no change (622 ± 448 mm. 2. , p = 0.041). The median cobalt ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 1.8 µg/L, respectively. The median chromium ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 3.1 µg/L, respectively. No significant differences were observed between the levels of either metal at initial and subsequent MRI. Conclusions. The present results suggest that pseudotumors frequently change in size in asymptomatic patients, and our hypothesis was verified. The initial size of pseudotumor was bigger in pseudotumors with increased in size than in those with decreased in size or no change. And we might predict that bigger pseudotumors would tend to increase in size

Background. Total ankle arthroplasty is an accepted alternative to arthrodesis of the ankle. However, complication and failure rates remain high compared to knee and hip arthroplasty. Long-term results of the Scandinavian Total Ankle Replacement (STAR) are limited, with variable complication and failure rates observed. This prospective study presents the long-term survivorship and the postoperative complications of the STAR prosthesis. Additionally, clinical outcomes and radiographic appearance were evaluated. Methods. Between May 1999 and June 2008, 134 primary total ankle arthroplasties were performed using the STAR prosthesis in 124 patients. The survivorship, postoperative complications and reoperations were recorded, with a minimum follow-up period of 7.5 years. Clinical results were assessed using the Foot Function Index (FFI) and the Kofoed score. The presence of component migration, cysts and radiolucency surrounding the prosthesis components, heterotopic ossifications and progression of osteoarthritis in adjacent joints were determined. Results. The cumulative survival was 78% after a 10-year follow-up period (Figure 1). An ankle arthrodesis was performed in the 20 ankles that failed. Fourteen polyethylene insert fractures occurred. Other complications occurred in 29 ankles, requiring secondary procedures in 21 ankles. Nevertheless, the postoperative clinical results improved significantly. Osteolytic cysts were observed in 59 ankles and the surface area of these cysts increased during follow-up, without any association with the prosthesis alignment or clinical outcome. Heterotopic ossifications at the medial malleolus were present in 58 cases and at the posterior tibia in 73 cases, with no effect on clinical outcome. Osteoarthritis of the subtalar joint and talonavicular joint developed in 9 and 11 cases, respectively. Conclusion. The long-term clinical outcomes for the STAR were found to be satisfactory. These results are consistent with previous studies; however, the survival and complication rates are still disappointing compared to the results obtained in knee and hip arthroplasty. Higher rates of successful outcomes following ankle arthroplasty are required, and these results highlight the need for further research to clarify the origin and significance of the reported complications. Figure 1. Kaplan-Meier survivorship analysis with revision or removal of the tibia and/or the talus component for any reason as the endpoint, showing 78% (95% confidence interval 0.63–0.88) survival at 10.28 years follow-up. For figure, please contact authors directly

Ceramic-on-ceramic bearings provide a solution to the osteolysis seen with traditional metal-on-polyethylene bearings. Sporadic reports of ceramic breakage and squeaking concern some surgeons and this bearing combination can show in vivo signs of edge loading wear which was not predicted from in vitro studies. Taper damage or debris in the taper between the ceramic and metal may lead to breakage of either a ceramic head or insert. Fastidious surgical technique may help to minimise the risk of ceramic breakage. Squeaking is usually a benign complication, most frequently occurring when the hip is fully flexed. Rarely, it can occur with each step of walking when it can be sufficiently troublesome to require revision surgery. The etiology of squeaking is multifactorial origin. Taller, heavier and younger patients with higher activity levels are more prone to hips that squeak. Cup version and inclination are also relevant factors. Fifty-five ceramic bearings revised at our center were collected over 12 years. Median time to revision was 2.7 years. Forty-six (84%) cases had edge loading wear. The median femoral head wear volume overall was 0.2mm. 3. /yr, for anterosuperior edge loading was 2.0mm. 3. /yr, and the median volumetric wear rate for posterior edge loading was 0.15mm. 3. /yr (p=0.005). Osteolysis following metal-on-polyethylene total hip arthroplasty (THA) is well reported. Earlier generation ceramic-on-ceramic bearings did produce some osteolysis, but in flawed implants. As 3rd and now 4th generation ceramic THAs come into mid- and long-term service, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. The technique used by radiologists for identifying the nature of lesions on Computed Tomography (CT) scan is the Hounsfield score which will identify the density of the tissue within the lucent area. Commonly the radiologist will have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA, which states there is osteolysis? This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term 3rd generation ceramic-on-ceramic uncemented hip arthroplasties in our department. Methods. Pelvic CT scans were performed on the first 27 patients from a cohort of 301 patients undergoing 15-year review with 3rd generation alumina-alumina cementless THAs. The average follow-up was 15 years (15–17). The CT scans were reviewed against pre-operative and post-operative radiographs and reviewed by a second musculoskeletal specialist radiologist. Results. Eleven of the CT scans were reported to show acetabular osteolysis, two reported osteolysis or possible pre-existing cyst and one reported a definitive pre-existing cyst. After review of previous imaging including pre-operative radiographs, eleven of the thirteen patients initially reported to have osteolysis were found to have pre-existing cysts or geodes in the same size and position as the reported osteolysis, and a further patient had spot-welds with stress-shielding. One patient with evidence of true osteolysis awaits aspiration or biopsy to determine if he has evidence of ceramic wear or metallosis. Conclusions. Reports of osteolysis on CT should be interpreted with care in modern ceramic-on-ceramic THA to prevent unnecessary revision. Further imaging and investigations may be necessary to exclude other conditions such as geodes, or stress shielding which are frequently confused with osteolysis on CT scans

Thermal damage to bone related to the exothermic polymerisation of bone cement (PMMA) remains a concern. A series of studies were conducted to examine PMMA bone interface during cemented arthroplasty. In vitro and in vivo temperature distributions were performed in the laboratory and human and animal surgery. In vivo (10 patients) measurements of cement temperature during cementing of BHR femoral prosthesis using thermocouples. Intra-operative measurement of cement temperature in BHR in the presence of femoral head cysts was examined in patients. The BHR femoral heads were sectioned to assess cement mantle as well as position of thermocouples. An additional study was performed in sheep with PMMA implanted into cancellous defects. Thermocouples were used to monitor temperature in the cement as well as adjacent bone. Histology and CT was used to assess any thermal damage. The exothermic reaction of PMMA during polymerization does indeed result in an increase in temperature at the interface with bone. The in vivo study recorded a maximum temperature of 49.12C for approximately three minutes in the cancellous bone underneath the BHR prosthesis. This exposure is probably not sufficient to cause significant injury to the femoral head. The maximum temperature of the cement on the surface of the bone was 54.12C, whereas the maximum recorded in the cement in the mixing bowl was 110.2C. In the presence of artificial cysts within the bone, however, temperatures generated within the larger cysts, and even at the bone-cement interface of these cysts, reached levels greater than those previously shown to be harmful to bone. This occurred in one case even in the 1 cc cyst. Routine histology revealed a fibrous layer at the cement bone interface in the sheep study. Fluorescent microscopy demonstrated bone label uptake adjacent to the defect site. Histology did not reveal thermal necrosis in the defects in terms of bony necrosis. CT data was used to measure the amount of PMMA placed into each defect. This analysis revealed a range of volumes that did not seem to influence the histology. The heat of cement polymerisation in resurfacing as performed in our study is not sufficient to cause necrosis. This may reflect the ability of the body to rapidly conduct heat away by acting as a heat sink. The temperature-conducting properties of the metal prosthesis are also likely to be important

The aim of this study is to assess the long-term results of Ethibloc (Ethnor Laboratories/ Ethicon, Norderstedt, Germany) injection in aneurysmal bone cysts (ABC). 33 patients with aneurysmal bone cysts were treated with computed tomographic (C.T) guided percutaneous injection of Ethibloc into the cyst cavity. 22 patients had Ethibloc injection as primary treatment and 11 patients had presented to us with recurrence following previous procedures including steroid injection, bone marrow injection, curettage bone grafting and various other surgical procedures. The mean follow-up was 54 (22-90) months. Symptoms were relieved in all patients. 2 patients were lost to follow up. 18 (58%) of the 31 patients followed, had complete resolution of the lesion, 11 (35.5%) patients had partial healing (asymptomatic residual non progressive lytic areas). 2 (6.5%) patients showed recurrence in the proximal humerus during the follow-up. They are under follow-up but asymptomatic. 2 patients encountered more significant complications after the procedure. Ethibloc injection is a relatively simple, minimally invasive alternative procedure for the treatment of ABC, and makes open operation unnecessary by stopping the expansion of the cyst and inducing endosteal new bone formation. This technique may be used as the primary management of ABCs excluding spinal lesions as shown by this long-term follow-up study

Bioabsorbable screws for anterior cruciate ligament reconstruction (ACLR) have been shown to be associated with femoral tunnel widening and cyst formation. To compare a poly-L-lactide–hydroxyapatite screw (PLLA-HA) with a titanium screw with respect to clinical and radiological outcomes over a 5 year period. 40 patients were equally randomized into 2 groups (PLLA-HA vs titanium) and ACLR performed with a 4 strand hamstring graft with femoral tunnel drilling via the anteromedial portal. Evaluation at 2 and 5 years was performed using the International Knee Documentation Committee assessment (IKDC), Lysholm knee score, KT 1000 arthrometer, single-legged hop test. Magnetic resonance imaging was used to evaluate tunnel and screw volume, ossification around the screws, graft integration and cyst formation. There was no difference in any clinical outcome measure at 2 or 5 years between the 2 groups. At 2 years, the PLLA-HA femoral tunnel was significantly smaller than the titanium screw tunnel (p=0.015) and at 5 years, there was no difference. At 2 years the femoral PLLA-HA screw was a mean 76% of its original volume and by 5 years, 36%. At 2 years the tibial PLLA-HA screw mean volume was 68% of its original volume and by 5 years, 46%. At 5 years, 88% of femoral tunnels and 56% of tibial tunnels demonstrated a significant ossification response. There was no increase in cyst formation in the PLLA-HA group and no screw breakages. The PLLA-HA screw provides adequate aperture fixation in ACLR with excellent functional outcomes. It was not associated with femoral tunnel widening or increased cyst formation when compared with the titanium screw. The resorbtion characteristics appear favourable and the hydroxyapatite component of the screw may stimulate osteoconduction, contributing to these results. The PLLA-HA screw is a good alternative to a titanium screw in ACLR, which may aid revision procedures and allow for imaging without artifact

Introduction. Osteloysis following metal-on-UHMW polyethylene Total Hip Arthroplasty (THA) is well reported, as is lack of osteolysis following Ceramic-on-Ceramic (CoC)THA. Early ceramic failures did report some osteolysis, but in flawed implants. As 3rd and now 4th generation ceramic THAs come into mid- and long-term use, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. Osteolysis reported after 3rd generation CoC THA often included metallosis due to neck rim impingement. In our department we have revised only 2 hips in over 6000 CoC THAs for osteolysis. Both had evidence of metallosis as well as ceramic wear. The technique used by Radiologists for identifying the nature of lesions on CT is the Hounsfield score which will identify the density of the tissue within the lucent area. It is common for radiologist to have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA which states there is osteolysis? Revision of such implants in elderly patients has a high risk of morbidity and mortality. Objectives. This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term third generation ceramic-on-ceramic uncemented hip arthroplasties in our department. Methods. Pelvic CT scans were performed on the first 27 patients from a cohort of 301 patients undergoing 15 year review with 3rd generation alumina-alumina cementless THAs. The average follow-up was 15 years (15–17). The CT scans were reviewed against pre-operative and post-operative radiographs and reviewed by a second musculoskeletal specialist radiologist. Results. Eleven of the CTscans were reported to show acetabular osteolysis, two reported osteolysis or possible pre-existing cyst and one reported a definitive pre-existing cyst. After review of previous imaging including pre-operative radiographs, eleven of the thirteen patients initially reported to have osteolysis were found to have pre-existing cysts or geodes in the same size and position as the reported osteolysis, and a further patient had spot-welds with stress-shielding. One patient with evidence of true osteolysis awaits aspiration or biopsy to determine if he has evidence of ceramic wear or metallosis. Conclusions. Reports of osteolysis on CT should be interpreted with care in modern ceramic-on-ceramic THA to prevent unnecessary revision. Further imaging and investigations may be necessary to exclude other conditions such as geodes, or stress shielding which are frequently confused with osteolysis on CT scans

The primary goal of this study was to understand the subjective impact of a diagnosis of Simple Bone Cyst on children with regards to activity participation and psychosocial development. We aimed to explore the concepts of labeling, embodiment and activity participation to understand the impact of SBC. This was a qualitative study. Ten children between the ages of 4 and 17 years with SBC and their families participated in semi-structured interviews related to activity participation, social interactions and psychological impact of SBC. Interview questions were derived from psychology, sociology and philosophy literatures pertaining to illness and activity, sense of embodiment, self-concept and interactions with the social environment. Interviews were transcribed and analyzed using thematic analysis. First, children and families view SBC as an injury more than an illness and did not experience labeling or significant changes in embodiment. Second, SBCs cause anxiety in children related fear of fracture or pain, however normal function and activity participation were maintained. Third, there were significant shortcomings identified in the communication and the decision-making process between families and physicians regarding SBC management. SBC as a benign disease does not neatly fit into the category of illness or injury based on children's experiences. Children who previously perceived themselves as normal feel different and not normal following diagnosis with SBC. The experience of parents is largely one of anxiety, and much of that anxiety is derived from the uncertainty over the treatment plans for their child. The proposed framework of normality allows for the more temporary and fluid changes in perception experienced by the children in our study. The results of this study suggest that the current decision-making process in SBC is unsatisfactory leading to anxiety and worry. Parents felt pressure to make decisions regarding surgery without feeling that they sufficient information. Though understanding how children experience SBCs and how parents experience the treatment course of their child with SBC, we can shared decision-making as a potential way to reduce parents' anxiety and limit negative experience in children

The TruFit® plug is a cylindrical scaffold designed to bridge defects in articular cartilages. It is a porous structure with interconnected pores, which gives it the capability of providing a framework for the ingrowth new tissue and remodelling to articular cartilage and bone. The aim of this study was to assess the radiological incorporation of TruFit® Plugs using MRI. Between December 2007 & August 2009, 22 patients underwent treatment of a chondral or osteochondral lesion using one or more TruFit Plugs. At a minimum of 2 years, 10 patients (12 lesions) were MRI scanned and assessed with a modified MOCART Scoring system by an independent Consultant Musculoskeletal Radiologist. 8 patients were no longer contactable and 4 patients declined MRI as their knee was asymptomatic. 8 of 12 lesions showed congruent articular cartilage cover with a surface of a similar thickness and signal to the surrounding cartilage and reconstitution of the subchondral bone plate. 2 lesions had a thicker congruent articular surface with a similar signal to the surrounding articular cartilage without restoration of the subchondral bone plate. 2 lesions showed no graft incorporation at all and were filled with granulation tissue. Full incorporation of the bony portion of the plug had occurred in only 3 lesions with partial incorporation in 7 lesions. The remaining portion of these 7 lesions looked cystic on MRI. The MRI appearances of the TruFit® Plug at 2 years are encouraging with the majority (83%) showing good restoration of the articular surface with tissue of similar thickness, congruity and signal as the surrounding articular cartilage. However complete incorporation of the TruFit® Plug is rare and cystic change is common. The significance of this cystic change is not clear