Aims. The aim of this study was to determine the diagnostic utility of histological analysis in spinal biopsies for spondylodiscitis (SD). Patients and Methods. Clinical features, radiology, results of microbiology, histology, and laboratory investigations in 50 suspected SD patients were evaluated. In 29 patients, the final (i.e. treatment-based) diagnosis was pyogenic SD; in seven patients, the final diagnosis was mycobacterial SD. In pyogenic SD, the neutrophil polymorph (NP) infiltrate was scored semi-quantitatively by determining the mean number of NPs per (×400) high-power field (HPF). Results. Of the 29 pyogenic SD patients, 17 had positive microbiology and 21 positive histology (i.e. one or more NPs per HPF on average). All non-SD patients showed less than one NP per HPF. The presence of one or more NPs per HPF had a diagnostic sensitivity of 72.4%, specificity 100%, accuracy 100%, positive predictive value (PPV) 81.0%, and negative predictive value (NPV) 61.9%. Sensitivity, specificity, and accuracy were greater using the criterion of positive histology and/or microbiology than positive histology or microbiology alone. Granulomas were identified histologically in seven mycobacterial SD patients, and positive microbiology was detected in four. Conclusion. The diagnosis of pyogenic SD was more often confirmed by positive histology (one or more NPs per HPF on average) than by microbiology, although diagnostic sensitivity was greater when both histology and microbiology were positive. Cite this article: Bone Joint J 2019;101-B:246–252

This animal study compares different methods of performing an osteotomy, including using an Erbium-doped Yttrium Aluminum Garnet laser, histologically, radiologically and biomechanically. A total of 24 New Zealand rabbits were divided into four groups (Group I: multihole-drilling; Group II: Gigli saw; Group III: electrical saw blade and Group IV: laser). A proximal transverse diaphyseal osteotomy was performed on the right tibias of the rabbits after the application of a circular external fixator. The rabbits were killed six weeks after the procedure, the operated tibias were resected and radiographs taken. . The specimens were tested biomechanically using three-point bending forces, and four tibias from each group were examined histologically. Outcome parameters were the biomechanical stability of the tibias as assessed by the failure to load and radiographic and histological examination of the osteotomy site. . The osteotomies healed in all specimens both radiographically and histologically. The differences in the mean radiographic (p = 0.568) and histological (p = 0.71) scores, and in the mean failure loads (p = 0.180) were not statistically significant between the groups. . Different methods of performing an osteotomy give similar quality of union. The laser osteotomy, which is not widely used in orthopaedics is an alternative to the current methods. Cite this article: Bone Joint J 2015;97-B:1628–33

The aim of this study was to obtain detailed long-term data on the cement-bone interface in patients with cemented stems, implanted using the constrained fixation technique. A total of eight stems were removed together with adjacent bone during post-mortem examinations of patients with well-functioning prostheses. Specimens were cut at four defined levels, contact radiographs were obtained for each level, and slices were prepared for histological analysis. Clinical data, clinical radiographs, contact radiographs and histological samples were examined for signs of loosening and remodelling. The mean radiological follow-up was 9.6 years and all stems were well-fixed, based on clinical and radiological criteria. Contact radiographs revealed an incomplete cement mantle but a complete filling of the medullary canal for all implants. Various amounts of polyethylene particles were evident at the cement-bone interface of seven stems, with no accompanying inflammatory reaction. Cortical atrophy and the formation of an ‘inner cortex’ were confirmed in six of eight stems by contact radiographs and histology, but were only visible on two clinical radiographs. Our results confirm that a complete cement mantle is not essential for the survival of Müller straight stems into the mid term, and support our hypothesis that no benefit to long-term survival can be expected from modern cementing techniques

Autologous chondrocyte implantation is an option in the treatment of full-thickness chondral or osteochondral injuries which are symptomatic. The goal of surgery and rehabilitation is the replacement of damaged cartilage with hyaline or hyaline-like cartilage, producing improved levels of function and preventing early osteoarthritis. The intermediate results have been promising in terms of functional and clinical improvement. Our aim was to explore the hypothesis that the histological quality of the repair tissue formed after autologous chondrocyte implantation improved with increasing time after implantation. In all, 248 patients who had undergone autologous chondrocyte implantation had biopsies taken of the repair tissue which then underwent histological grading. Statistical analysis suggested that with doubling of the time after implantation the likelihood of a favourable histological outcome was increased by more than fourfold (p < 0.001)

The radiographic and histological features of radiolucent areas at the cement-bone interface were correlated in 15 specimens retrieved at post-mortem from patients who had undergone cemented total hip arthroplasty, two weeks to 15 years prior to death. All but one of the components were securely fixed, as demonstrated by direct measurements of micromotion. Extensive radiolucencies were present in all but one case. In 11 of the 14 specimens with radiolucencies, histological examination showed that the radiolucent areas represented regions of osteoporosis and bone remodelling. The remodelling changes were characterised by osteoporosis, cancellisation and thinning of the endosteal cortex, and osteopenia of the trabecular bone. In two specimens the appearance of radiolucency was found to be due to fibrous tissue at the cement-bone interface and in one specimen there was a mixed picture of osteolysis and fibrosis. The study demonstrates that radiolucent lines can occur with well-fixed components and that they may commonly represent osteoporosis rather than the presence of a fibrous membrane at the cement-bone interface

In a prospective study of the measurement of osteoporosis in patients with fracture of the femoral neck, we compared a histological with a radiological method. We found no significant correlation between histological planimetry and the radiological six metacarpal hand index in patients with either cervical or trochanteric fractures. This demonstrates that metacarpal morphometry cannot predict histological osteoporosis of the iliac crest

Vancomycin-supplemented allografts provide biological restoration of bone stock and sound fixation with a low incidence of re-infection. Experimental incorporation of these grafts is similar to allografts without vancomycin. However, the underlying biology remains unknown. We report the first histological observations of vancomycin-supplemented impacted bone allografts in two reconstructions performed 14 and 20 months after revision surgery because of a periprosthetic fracture. Areas of active bone remodelling (creeping substitution), as well as calcified bone trabeculae and graft particles embedded in dense fibrous tissue, were observed with osteoid and fibroconnective tissue surrounding polymethylmethacrylate particles. These pathological findings are similar to those reported in allografts without vancomycin and support the hypothesis that high levels of vancomycin do not affect the incorporation of bone graft

Acetabular dysplasia was produced in 24 immature white rabbits. A rotational acetabular osteotomy was then carried out and radiological and histological studies of the articular cartilage were made. In the hips which did not undergo osteotomy, radiographs at 26 weeks showed that residual subluxation remained and arthritic changes such as narrowing of the joint space or dislocation were still seen. However, in the operated group there was a remarkable increase in cover, but arthritic changes were not observed. After 24 weeks, the Mankin grading score in the operated group was significantly lower than that in the non-operated group. The latter hips showed an irregular surface of the cartilage, exfoliation and proliferation of synovial tissue. In those undergoing osteotomy, primary cloning of chondrocytes or hypercellularity was seen and at 24 weeks after operation and metaplasia of the cartilage in the fibrous tissue was observed in the boundary between the medial area of the acetabulum and the acetabular fossa

We describe the histology of a specimen taken from an amputated leg seven months after a 15 cm bone gap in the tibia had been closed by bone transport. Lengthening appeared to have occurred by repeated minor trauma to the bone, with the fractured trabeculae in sufficiently close contact for the repair process to proceed. Osteogenesis did not occur through a cartilage phase, but the fracture gaps were bridged by collagen fibres, around which new bone formed. Microfractures had repaired by primary healing with woven bone and with no microcallus. Small regions of bone were necrotic. Resorption of the necrotic bone and remodelling of the immature bundle and woven bone were still at an early stage, suggesting that complete remodelling in man may take years rather than months

This paper describes a study in the human femur of the relationship between cell division in growth cartilage and overall bone growth. Growth rates for the distal femur from birth to eighteen years were determined from serial radiographs available from the Harpenden Growth Study; An average of 1-4 cm/year was found for the ages of five to eight years. The development of the growth plate is illustrated in a series of photomicrographs of femur sections. These sections were also used for quantitative histology; The length of the proliferation zone was estimated from cell counts to be twenty-four cells per column. On the basis of this value and the measured growth rate, an approximate mean cycle time of twenty days was found for the proliferating cells of the human growth plate. Since the corresponding cycle time is two days for rodent growth plates, which also have a different structure, it is unwise to extrapolate the findings in this tissue from mouse to man

We have studied the histological appearances of forty femoral heads with idiopathic avascular necrosis. The characteristic histopathological changes of recurrent necrosis were present in 83 per cent. Recurrent necrosis occurred widely after revascularisation had progressed as far as the subchondral zone. The aetiology of idiopathic avascular necrosis of the femoral head may be a chronic condition which produces repeated infarction. The deformation and incomplete revascularisation of the femoral head may be due to repeated episodes of infarction as well as to mechanical factors related to weight-bearing

A 65-year-old man presented with a painful hip five years after a cemented replacement. Histological examination of a biopsy taken from tissue surrounding the femoral implant showed infiltration of a squamous-cell carcinoma. Further investigation revealed a primary growth in the left lung. This rare example of a metastasis in relation to a joint replacement illustrates the necessity for histological examination of the tissue adjacent to a loose prosthesis

We report the histology of a femur retrieved 3.5 years after a cemented revision of a hip replacement in which impaction allografting had been used to fill two large cortical defects. The allograft chips had largely been replaced by viable cortical bone, and the interface between cement and tissue resembled that seen after primary cemented arthroplasty

In an attempt to improve the accuracy of diagnosis, 16 patients suffering from Morton's metatarsalgia were investigated clinically and electrophysiologically. The histological findings were related to these observations. The precise aetiology of Morton's metatarsalgia remains obscure, but the findings are compatible with an entrapment syndrome. Nerve conduction studies have a place in the investigation of patients with atypical presentation of pain in the foot. Further refinement of the electrophysiological technique should be possible

Previous perfusion studies of the rotator cuff have demonstrated an area of hypovascularity in the distal part of the supraspinatus tendon. This has been implicated in the pathogenesis of its rupture. We performed a quantitative histological analysis of the vascularity of the tendons of supraspinatus and infraspinatus. Vessel number, size and the percentage of the tendon occupied by vessels were measured at 5 mm intervals from the humeral insertions to the muscle bellies. Both tendons were hypovascular in their distal 15 mm. No significant difference was demonstrated between the vascularity of supraspinatus and infraspinatus. We conclude that factors other than vascularity are important in the pathogenesis of supraspinatus rupture

We have performed an arthroscopic and histological study of the remodelling process of allogeneic tendons transplanted into the human knee as anterior cruciate ligament substitutes. Arthroscopic observations from six weeks to 55 months after operation showed that the grafts were viable, and that early surface hypervascularity subsided with time; moreover, these appearances remained unchanged from 11 months postoperatively onwards. Histological studies from three to 55 months after operation showed that all the grafts were infiltrated with fibroblasts, and that cellularity in their substance reduced with time, remaining unchanged from 18 months onwards; the collagen bundles were aligned as in a normal ligament from six months onwards. These findings suggest that the grafts reach maturity within the first 18 months and remain unchanged as viable ligaments thereafter

In an experimental clinical study, 25 implants of pure titanium were inserted into the proximal tibia of 11 volunteer patients, four with rheumatoid arthritis and seven with osteoarthritis. The implants were removed from five weeks to 24 months later and detailed histological analysis was performed. The implants generally healed with direct bone-metal contact, showing so-called osseointegration. Only one of the 21 implants which had been in place for over five months did not show osseointegration, probably because of inadequate primary contact with bone. The presence of rheumatoid disease did not prevent osseointegration, but accompanying osteoporosis seemed to be a risk factor

In talipes equino-varus the diminished bulk of the calf muscle suggests a neuromuscular defect. Accordingly, biopsies were taken from the postero-medial and peroneal muscle groups, and occasionally from abductor hallucis, in sixty patients mostly under the age of five years; 111 were studied histochemically and histologically, and a further fifty-three by electron-microscopy. Histochemical anomalies were revealed in ninety-two specimens; the muscle fibres in the other nineteen varied in size but were abnormal at the ultramicroscopic level, as were all specimens examined with the electron microscope. Evidence of neurogenic disease was seen in most instances and was more obvious in the older patients. The pattern of abnormality was similar in both muscle groups. It is thought that shortening of the postero-medial muscles may result from a small increase of fibrosis due to minor innervation changes occurring in intra-uterine life. There is evidence that immobilisation, stretching or relaxation of muscles does not account for the anomalies observed. This study of the extrinsic muscles in talipes equino-varus indicates a dominant neurogenic factor in its causation

Threaded acetabular components are widely used in cementless total hip replacement, despite a poor understanding of the nature of the bone-implant interface. We have examined one case in which the threaded titanium ring appeared to be well incorporated with no discernible radiolucency. Microradiography and histology surprisingly showed that the threads were entirely encapsulated in fibrous tissue. This raises doubt about the relevance of plain radiography to the analysis of the acetabular interface

We studied nine patients who had had a transtrochanteric anterior rotational osteotomy, as developed by Sugioka, for osteonecrosis of the femoral head. At a mean of 2.5 years after the initial operation we carried out a histological study of the previously necrotic femoral head which had not shown collapse of the new primary weight-bearing site. In seven joints, there was proliferation of fibrous tissue in the dead trabeculae with vascular ingrowth. New bone covering dead trabeculae created the characteristic appearance of ‘creeping substitution’. However, these changes were limited and did not extend over the entire necrotic area. Dead bone remained in all the cases. In the other two heads we did not observe proliferation of fibrous tissue or vascular ingrowth, only dead trabeculae and dead bone marrow

Total hip replacement in patients with advanced osteonecrosis of the femoral head is often complicated by early loosening of the femoral component. Recent evidence has suggested that abnormal bone extending into the proximal femur may be responsible for the early failure of the femoral component. We aimed to identify which patients were at high risk of early failure by evaluating gadolinium-enhanced MR images of histologically-confirmed osteonecrotic lesions beyond the femoral head.

Although the MR signal intensity has been shown to correlate well with osteonecrosis in the femoral head, it was found to be relatively insensitive at identifying lesions below the head, with a sensitivity of only 51% and a predictive value of a negative result of only 48%. However, the specificity was 90%, with the predictive value of a positive MRI finding being 86%. Only those patients with osteonecrosis of the femoral head secondary to sickle-cell disease, who are known to be at high risk of early loosening, had changes in the MR signal in the greater trochanter and the femoral shaft. This observation suggests that changes in the MR signal beyond the femoral head may represent osteonecrotic lesions in areas essential for the fixation of the femoral component. Pre-operative identification of such lesions in the neck of the femur may be important when considering hip resurfacing for osteonecrosis of the femoral head, following which early loosening of the femoral component and fracture of the neck are possible complications.

We studied the fixation of a cementless titanium femoral prosthesis partially coated with hydroxyapatite ceramic (HAC) 10.4 months after implantation. Histomorphological investigation showed extensive new bone formation between the HAC coating and the bone bed; morphometry showed bone contact indices of up to 91.60%. There were a number of resorption lacunae on the HAC coat with depths of up to 76.6 microns and widths of up to 453 microns. Our results confirmed that considerable bone remodelling had taken place and that the apatite-coated prosthesis had united with bone despite the lack of appreciable immediate press-fit. Hydroxyapatite particles which had been released did not appear to show any negative effects on the stability of the implant.

Thirty-nine patients underwent reconstruction of the anterior cruciate ligament with carbon-fibre and a MacIntosh repair; all had a negative pivot shift test after operation. Some patients had persistent pain, mild effusion and synovial thickening; in 10 of these patients the symptoms warranted arthroscopic examination and biopsy at a mean of 16.9 months after the repair. Arthroscopy revealed that the carbon-fibre had not induced the formation of a "new ligament" and that the repair was merely covered by a thin, fibrous sheath. Histological investigations confirmed this finding, with only a suggestion of a fibroblastic response to carbon-fibre found in two patients. Particles of carbon-fibre were found scattered through the knees. Synovitis and breakdown of the skin over subcutaneous carbon-fibre complicated treatment. Failure of the carbon-fibre to bond to bone was detected radiographically.

We report the experimental use of three different biological implants to restore articular surface defects: glutaraldehyde-fixed bovine meniscal xenograft, glutaraldehyde-fixed bovine costal cartilage xenograft, and viable osteochondral allografts. The grafts were implanted in the knees of 19 goats who were allowed free-field activity and were studied for up to one year. The natural articular surfaces of meniscal fibrocartilage provided excellent articular surfaces at all times. Equally good articular surfaces were restored by host tissue growth covering costal cartilage grafts at six months, but by 12 months this surface had degenerated. The majority of the allografts survived and integrated with the host at six months, but many showed signs of failure at 12 months. Only three out of seven ungrafted defects healed completely at six months and the healed surfaces were degenerating at 12 months.

We have reviewed 41 patients with pustulotic arthro-osteopathy (PAO), all having both the typical skin rash of pustulosis palmaris et plantaris and bone lesions. The most common bones affected were the clavicle, sternum and ribs. Changes in the clavicle started, not as an enthesopathy, but with periosteal bone formation, indicative of a bone marrow disorder. About 30% of the patients also had lesions in the spine, sacroiliac region or the peripheral joints. Bone and joint lesions followed a variable and intermittent clinical course over a long period of time. Biopsies in eight cases showed similar inflammatory changes in skin, bone and synovium, with infiltration of lymphocytes and polymorphonuclear leucocytes. This suggests that there is a common pathogenesis in the three tissues.

We have studied core biopsy specimens from 16 femoral heads affected by idiopathic avascular necrosis at the silent stage, when there were no clinical or radiographic manifestations but scintigraphy was positive. All the specimens showed necrosis of trabeculae and of bone marrow, but the most common and characteristic feature was evidence of old and new haemorrhage in the marrow. In the areas of intramedullary haemorrhages, trabeculae and bone marrow were completely necrotic, with a transitional area of incomplete necrosis between these areas and those without haemorrhagic lesions, where the trabeculae and bone marrow were normal. There was good correlation between necrosis and haemorrhagic episodes, and it was concluded that repeated intramedullary haemorrhage at the silent stage is probably related to the pathogenesis of idiopathic avascular necrosis of the femoral head.

Aims. Histology is widely used for diagnosis of persistent infection during reimplantation in two-stage revision hip and knee arthroplasty, although data on its utility remain scarce. Therefore, this study aims to assess the predictive value of permanent sections at reimplantation in relation to reinfection risk, and to compare results of permanent and frozen sections. Methods. We retrospectively collected data from 226 patients (90 hips, 136 knees) with periprosthetic joint infection who underwent two-stage revision between August 2011 and September 2021, with a minimum follow-up of one year. Histology was assessed via the SLIM classification. First, we analyzed whether patients with positive permanent sections at reimplantation had higher reinfection rates than patients with negative histology. Further, we compared permanent and frozen section results, and assessed the influence of anatomical regions (knee versus hip), low- versus high-grade infections, as well as first revision versus multiple prior revisions on the histological result at reimplantation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), chi-squared tests, and Kaplan-Meier estimates were calculated. Results. Overall, the reinfection rate was 18%. A total of 14 out of 82 patients (17%) with positive permanent sections at reimplantation experienced reinfection, compared to 26 of 144 patients (18%) with negative results (p = 0.996). Neither permanent sections nor fresh frozen sections were significantly associated with reinfection, with a sensitivity of 0.35, specificity of 0.63, PPV of 0.17, NPV of 0.81, and accuracy of 58%. Histology was not significantly associated with reinfection or survival time for any of the analyzed sub-groups. Permanent and frozen section results were in agreement for 91% of cases. Conclusion. Permanent and fresh frozen sections at reimplantation in two-stage revision do not serve as a reliable predictor for reinfection. Cite this article: Bone Joint J 2024;106-B(4):372–379

Aims. The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB. Methods. A total of 284 patients with clinically and radiologically suspected infectious spondylodiscitis were prospectively recruited into the study. Image-guided biopsy of the vertebral lesion was performed and specimens were sent for various microbiological tests and histological examinations. The final diagnosis was determined using a composite reference standard based on clinical, radiological, serological, microbiological, and histological findings. The overall diagnostic yield of the biopsy, and that for each test, was calculated in light of the final diagnosis. Results. The final diagnosis was tuberculous spondylodiscitis in 250 patients (88%) and pyogenic spondylodiscitis in 22 (7.8%). Six (2.1%) had a noninfectious condition-mimicking infectious spondylodiscitis, and six (2.1%) had no definite diagnosis and improved without specific treatment. The diagnosis was made by image-guided biopsy in 152 patients (56%) with infectious spondylodiscitis. Biopsy was contributory in identifying 132/250 patients (53%) with tuberculous spondylodiscitis, and 20/22 patients (91%) with pyogenic spondylodiscitis. Histological examination was the most sensitive diagnostic modality, followed by Xpert MTB/RIF assay. Conclusion. Image-guided biopsy has a reasonably high diagnostic yield in patients with suspected infectious spondylodiscitis. A combination of histological examination, Xpert MTB/RIF assay, bacterial culture, and sensitivity provides high diagnostic accuracy in a country in which TB is endemic. Cite this article: Bone Joint J 2022;104-B(1):120–126

Aims. The aim of this study was to analyze the prevalence of culture-negative periprosthetic joint infections (PJIs) when adequate methods of culture are used, and to evaluate the outcome in patients who were treated with antibiotics for a culture-negative PJI compared with those in whom antibiotics were withheld. Methods. A multicentre observational study was undertaken: 1,553 acute and 1,556 chronic PJIs, diagnosed between 2013 and 2018, were retrospectively analyzed. Culture-negative PJIs were diagnosed according to the Muskuloskeletal Infection Society (MSIS), International Consensus Meeting (ICM), and European Bone and Joint Society (EBJIS) definitions. The primary outcome was recurrent infection, and the secondary outcome was removal of the prosthetic components for any indication, both during a follow-up period of two years. Results. None of the acute PJIs and 70 of the chronic PJIs (4.7%) were culture-negative; a total of 36 culture-negative PJIs (51%) were treated with antibiotics, particularly those with histological signs of infection. After two years of follow-up, no recurrent infections occurred in patients in whom antibiotics were withheld. The requirement for removal of the components for any indication during follow-up was not significantly different in those who received antibiotics compared with those in whom antibiotics were withheld (7.1% vs 2.9%; p = 0.431). Conclusion. When adequate methods of culture are used, the incidence of culture-negative PJIs is low. In patients with culture-negative PJI, antibiotic treatment can probably be withheld if there are no histological signs of infection. In all other patients, diagnostic efforts should be made to identify the causative microorganism by means of serology or molecular techniques. Cite this article: Bone Joint J 2022;104-B(1):183–188

Aims. A limited number of investigations with conflicting results have described perivascular lymphocytic infiltration (PVLI) in the setting of total knee arthroplasty (TKA). The purpose of this study was to determine if PVLI found in TKAs at the time of aseptic revision surgery was associated with worse clinical outcomes and survivorship. Methods. A retrospective review was conducted on 617 patients who underwent aseptic TKA revision who had histological analysis for PVLI at the time of surgery. Clinical and radiological data were obtained pre- and postoperatively, six weeks postoperatively, and then every year thereafter. Results. Within this cohort, 118 patients (19.1%) were found to have PVLI on histological analysis. Re-revision was performed on 83 patients (13.4%) with no significant differences in all-cause or aseptic revisions between groups. A higher incidence of PVLI was noted in female patients (p = 0.037). There was no significant difference in improvement in the range of motion (p = 0.536), or improvement of KSC (p = 0.66), KSP (p = 0.61), or KSF (p = 0.3) clinical outcome scores between PVLI and no PVLI sub-groups. There was a higher incidence of a preoperative diagnosis of pain in the PVLI group compared with patients without PVLI (p = 0.002) present. Conclusion. PVLI found on large-scale histological analysis in TKAs at aseptic revision surgery was not associated with worse clinical outcomes or rates of re-revision. Cite this article: Bone Joint J 2021;103-B(6 Supple A):145–149

Aims. Osteofibrous dysplasia (OFD) is a rare benign lesion predominantly affecting the tibia in children. Its potential link to adamantinoma has influenced management. This international case series reviews the presentation of OFD and management approaches to improve our understanding of OFD. Methods. A retrospective review at three paediatric tertiary centres identified 101 cases of tibial OFD in 99 patients. The clinical records, radiological images, and histology were analyzed. Results. Mean age at presentation was 13.5 years (SD 12.4), and mean follow-up was 5.65 years (SD 5.51). At latest review, 62 lesions (61.4%) were in skeletally mature patients. The most common site of the tibial lesion was the anterior (76 lesions, 75.2%) cortex (63 lesions, 62.4%) of the middle third (52 lesions, 51.5%). Pain, swelling, and fracture were common presentations. Overall, 41 lesions (40.6%) presented with radiological deformity (> 10°): apex anterior in 97.6%. A total of 41 lesions (40.6%) were treated conservatively. Anterior bowing < 10° at presentation was found to be related to successful conservative management of OFD (p = 0.013, multivariable logistic regression). Intralesional excision was performed in 43 lesions (42.6%) and a wide excision of the lesion in 19 (18.8%). A high complication rate and surgical burden was found in those that underwent a wide excision regardless of technique employed. There was progression/recurrence in nine lesions (8.9%) but statistical analysis found no predictive factors. No OFD lesion transformed to adamantinoma. Conclusion. This study confirms OFD to be a benign bone condition with low rates of local progression and without malignant transformation. It is important to distinguish OFD from adamantinoma by a histological diagnosis. Focus should be on angular deformity, monitored with full-length tibial radiographs. Surgery is indicated in symptomatic patients and predicted by the severity of the initial angular deformity. Surgery should focus more on the deformity rather than the lesion. Cite this article: Bone Joint J 2022;104-B(2):302–308

Aims. The aim of this study was to identify factors associated with five-year cancer-related mortality in patients with limb and trunk soft-tissue sarcoma (STS) and develop and validate machine learning algorithms in order to predict five-year cancer-related mortality in these patients. Methods. Demographic, clinicopathological, and treatment variables of limb and trunk STS patients in the Surveillance, Epidemiology, and End Results Program (SEER) database from 2004 to 2017 were analyzed. Multivariable logistic regression was used to determine factors significantly associated with five-year cancer-related mortality. Various machine learning models were developed and compared using area under the curve (AUC), calibration, and decision curve analysis. The model that performed best on the SEER testing data was further assessed to determine the variables most important in its predictive capacity. This model was externally validated using our institutional dataset. Results. A total of 13,646 patients with STS from the SEER database were included, of whom 35.9% experienced five-year cancer-related mortality. The random forest model performed the best overall and identified tumour size as the most important variable when predicting mortality in patients with STS, followed by M stage, histological subtype, age, and surgical excision. Each variable was significant in logistic regression. External validation yielded an AUC of 0.752. Conclusion. This study identified clinically important variables associated with five-year cancer-related mortality in patients with limb and trunk STS, and developed a predictive model that demonstrated good accuracy and predictability. Orthopaedic oncologists may use these findings to further risk-stratify their patients and recommend an optimal course of treatment. Cite this article: Bone Joint J 2023;105-B(6):702–710

Aims. The aim of this study was to evaluate the optimal deep tissue specimen sample number for histopathological analysis in the diagnosis of periprosthetic joint infection (PJI). Methods. In this retrospective diagnostic study, patients undergoing revision surgery after total hip or knee arthroplasty (n = 119) between January 2015 and July 2018 were included. Multiple specimens of the periprosthetic membrane and pseudocapsule were obtained for histopathological analysis at revision arthroplasty. Based on the Infectious Diseases Society of America (IDSA) 2013 criteria, the International Consensus Meeting (ICM) 2018 criteria, and the European Bone and Joint Infection Society (EBJIS) 2021 criteria, PJI was defined. Using a mixed effects logistic regression model, the sensitivity and specificity of the histological diagnosis were calculated. The optimal number of periprosthetic tissue specimens for histopathological analysis was determined by applying the Youden index. Results. Based on the EBJIS criteria (excluding histology), 46 (39%) patients were classified as infected. Four to six specimens showed the highest Youden index (four specimens: 0.631; five: 0.634; six: 0.632). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of five tissue specimens were 76.5% (95% confidence interval (CI) 67.6 to 81.4), 86.8% (95% CI 81.3 to 93.5), 66.0% (95% CI 53.2 to 78.7), and 84.3% (95% CI 79.4 to 89.3), respectively. The area under the curve (AUC) was calculated with 0.81 (as a function of the number of tissue specimens). Applying the ICM and IDSA criteria (excluding histology), 40 (34%) and 32 (27%) patients were categorized as septic. Three to five specimens had the highest Youden index (ICM 3: 0.648; 4: 0.651; 5: 0.649) (IDSA 3: 0.627; 4: 0.629; 5: 0.625). Conclusion. Three to six tissue specimens of the periprosthetic membrane and pseudocapsule should be collected at revision arthroplasty and analyzed by a pathologist experienced and skilled in interpreting periprosthetic tissue. Cite this article: Bone Joint J 2023;105-B(2):158–165

Aims. The preoperative grading of chondrosarcomas of bone that accurately predicts surgical management is difficult for surgeons, radiologists, and pathologists. There are often discrepancies in grade between the initial biopsy and the final histology. Recent advances in the use of imaging methods have shown promise in the ability to predict the final grade. The most important clinical distinction is between grade 1 chondrosarcomas, which are amenable to curettage, and resection-grade chondrosarcomas (grade 2 and 3) which require en bloc resection. The aim of this study was to evaluate the use of a Radiological Aggressiveness Score (RAS) to predict the grade of primary chondrosarcomas in long bones and thus to guide management. Methods. A total of 113 patients with a primary chondrosarcoma of a long bone presenting between January 2001 and December 2021 were identified on retrospective review of a single oncology centre’s prospectively collected database. The nine-parameter RAS included variables from radiographs and MRI scans. The best cut-off of parameters to predict the final grade of chondrosarcoma after resection was determined using a receiver operating characteristic curve (ROC), and this was correlated with the biopsy grade. Results. A RAS of ≥ four parameters was 97.9% sensitive and 90.5% specific in predicting resection-grade chondrosarcoma based on a ROC cut-off derived using the Youden index. Cronbach’s α of 0.897 was derived as the interclass correlation for scoring the lesions by four blinded reviewers who were surgeons. Concordance between resection-grade lesions predicted from the RAS and ROC cut-off with the final grade after resection was 96.46%. Concordance between the biopsy grade and the final grade was 63.8%. However, when the patients were analyzed based on surgical management, the initial biopsy was able to differentiate low-grade from resection-grade chondrosarcomas in 82.9% of biopsies. Conclusion. These findings suggest that the RAS is an accurate method for guiding the surgical management of patients with these tumours, particularly when the initial biopsy results are discordant with the clinical presentation. Cite this article: Bone Joint J 2023;105-B(7):808–814

Aims. Intra-articular (IA) tumours around the knee are treated with extra-articular (EA) resection, which is associated with poor functional outcomes. We aim to evaluate the accuracy of MRI in predicting IA involvement around the knee. Methods. We identified 63 cases of high-grade sarcomas in or around the distal femur that underwent an EA resection from a prospectively maintained database (January 1996 to April 2020). Suspicion of IA disease was noted in 52 cases, six had IA pathological fracture, two had an effusion, two had prior surgical intervention (curettage/IA intervention), and one had an osseous metastasis in the proximal tibia. To ascertain validity, two musculoskeletal radiologists (R1, R2) reviewed the preoperative imaging (MRI) of 63 consecutive cases on two occasions six weeks apart. The radiological criteria for IA disease comprised evidence of tumour extension within the suprapatellar pouch, intercondylar notch, extension along medial/lateral retinaculum, and presence of IA fracture. The radiological predictions were then confirmed with the final histopathology of the resected specimens. Results. The resection histology revealed 23 cases (36.5%) showing IA disease involvement compared with 40 cases without (62%). The intraobserver variability of R1 was 0.85 (p < 0.001) compared to R2 with κ = 0.21 (p = 0.007). The interobserver variability was κ = 0.264 (p = 0.003). Knee effusion was found to be the most sensitive indicator of IA involvement, with a sensitivity of 91.3% but specificity of only 35%. However, when combined with a pathological fracture, this rose to 97.5% and 100% when disease was visible in Hoffa’s fat pad. Conclusion. MRI imaging can sometimes overestimate IA joint involvement and needs to be correlated with clinical signs. In the light of our findings, we would recommend EA resections when imaging shows effusion combined with either disease in Hoffa’s fat pad or retinaculum, or pathological fractures. Cite this article: Bone Joint J 2023;105-B(6):696–701

Aims. Clear cell sarcoma (CCS) of soft-tissue is a rare melanocytic subtype of mesenchymal malignancy. The aim of this study was to investigate the clinical and therapeutic factors associated with increased survival, stratified by clinical stage, in order to determine the optimal treatment. Methods. The study was a retrospective analysis involving 117 patients with histologically confirmed CCS, between July 2016 and November 2017, who were enrolled in the Bone and Soft Tissue Tumour Registry in Japan. Results. The five- and ten-year survival rates were 41% (95% confidence interval (CI) 29 to 52) and 37% (95% CI 25 to 49), respectively. On multivariable analysis, the size of the tumour of > 10 cm (p = 0.006), lymph node metastasis at the time of diagnosis (p < 0.001), distant metastases at the time of diagnosis (p < 0.001), and no surgery for the primary tumour (p = 0.019) were independently associated with a poor survival. For N0M0 CCS (n = 68), the development of distant metastases was an independent prognostic factor for survival (early (< 12 months), hazard ratio (HR) 116.78 (95% CI 11.69 to 1,166.50); p < 0.001; late (> 12 months), HR 14.79 (95% CI 1.66 to 131.63); p = 0.016); neoadjuvant/adjuvant chemotherapy (p = 0.895) and/or radiotherapy (p = 0.216) were not significantly associated with survival. The five-year cumulative incidence of local recurrence was 19% (95% CI 8 to 35) and the size of the tumour was significantly associated with an increased rate of local recurrence (p = 0.012). For N1M0 CCS (n = 18), the risk of mortality was significantly lower in patients who underwent surgery for both the primary tumour and lymph node metastases (HR 0.03 (95% CI 0.00 to 0.56); p = 0.020). For M1 CCS (n = 31), excision of the primary tumour was independently associated with better survival (HR 0.26 (95% CI 0.09 to 0.76); p = 0.013). There was no significant difference in survival between the different types of systemic treatment (p = 0.523). Conclusion. Complete excision of the primary tumour and lymph nodes is associated with a better survival in patients with CCS. Systemic treatment appears to provide limited benefits, demonstrating a pressing need for novel systemic agents. Cite this article: Bone Joint J 2023;105-B(11):1216–1225

Aims. The aim of this study was to investigate the incidence and characteristics of instrumentation failure (IF) after total en bloc spondylectomy (TES), and to analyze risk factors for IF. Methods. The medical records from 136 patients (65 male, 71 female) with a mean age of 52.7 years (14 to 80) who underwent TES were retrospectively reviewed. The mean follow-up period was 101 months (36 to 232). Analyzed factors included incidence of IF, age, sex, BMI, history of chemotherapy or radiotherapy, tumour histology (primary or metastasis; benign or malignant), surgical approach (posterior or combined), tumour location (thoracic or lumbar; junctional or non-junctional), number of resected vertebrae (single or multilevel), anterior resection line (disc-to-disc or intravertebra), type of bone graft (autograft or frozen autograft), cage subsidence (CS), and local alignment (LA). A survival analysis of the instrumentation was performed, and relationships between IF and other factors were investigated using the Cox regression model. Results. A total of 44 patients (32.4%) developed IF at a median of 31 months (interquartile range 23 to 74) following TES. Most IFs were rod fractures preceded by a mean CS of 6.1 mm (2 to 18) and LA kyphotic enhancement of 10.8° (-1 to 36). IF-free survival rates were 75.8% at five years and 56.9% at ten years. The interval from TES to IF peaked at two to three years postoperatively and continued to occur over a period of time thereafter; the early IF-developing group had greater CS at one month postoperatively (CS1M) and more lumbar TES. CS1M ≥ 3 mm and sole use of frozen autografts were identified as independent risk factors for IF. Conclusion. IF is a common complication following TES. We have demonstrated that robust spinal reconstruction preventing CS, and high-quality bone grafting are necessary for successful reconstruction. Cite this article: Bone Joint J 2023;105-B(2):172–179

Aims. Leucocyte esterase (LE) has been shown to be an accurate marker of prosthetic joint infection (PJI), and has been proposed as an alternative to frozen section (FS) histology for intraoperative diagnosis. In this study, the intraoperative assessment of LE was compared with FS histology for the diagnosis of prosthetic hip infection. Patients and Methods. A total of 119 patients undergoing revision total hip arthroplasty (THA) between June 2015 and December 2017 were included in the study. There were 56 men and 63 women with a mean age of 66.2 years (27 to 88). Synovial fluid was collected before arthrotomy for the assessment of LE using enzymatic colourimetric strips. Between five and six samples were stained with haematoxylin and eosin for FS histology, and considered suggestive of infection when at least five polymorphonuclear leucocytes were found in five high-power fields. Results. The sensitivity and specificity of the LE assay were 100% and 93.8%, respectively; the positive (PPV) and the negative (NPV) predictive values were 79.3% and 100%, respectively. The mean time between the collection of the sample and the result being known was 20.1 minutes (. sd. 4.4). The sensitivity and specificity of FS histology were 78.3% and 96.9%, respectively; the PPV and the NPV were 85.7% and 94.9%, respectively. The mean time between the collection of the sample and the result being known was 27.2 minutes (. sd. 6.9). Conclusion. The sensitivity of LE assay was higher, with similar specificity and diagnostic accuracy, compared with FS histology. The faster turnaround time, its ease of use, and low costs make LE assay a valuable alternative to FS histology. We now use it routinely for the intraoperative diagnosis of PJI. Cite this article: Bone Joint J 2019;101-B:372–377

Aims. Although chondrosarcomas (CSs) display true malignant features, including local recurrence (LR) and metastases, their behaviour in the hands and feet is thought to differ from that in other parts of the axial and appendicular skeleton by having a lower metastatic potential. The purpose of this study was to investigate the disease-specific and surgical factors that affect the local and systemic prognosis of CS of the hands and feet. Methods. A multicentre retrospective study was carried out at two tertiary sarcoma centres. A database search identified all patients with a CS treated between January 1995 and January 2018. There were 810 CSs of which 76 (9.4%) were located in the fingers, toes, metacarpals, and metatarsal bones. Results. The median age of the study population was 55 years (36 to 68) with a median follow-up of 52 months (22 to 87) months. Overall, 70% of the tumours were in the hand (n = 54) and 30% in the foot (n = 22). Predictors for LR were margin (p = 0.011), anatomical location (p = 0.017), and method of surgical management (p = 0.003). Anatomical location (p = 0.026), histological grade between 1 and 3 (p = 0.004) or 2 and 3 (p = 0.016), and surgical management (p = 0.001) were significant factors for LR-free survival. Disease-specific survival was affected by histological grade (p < 0.001), but not by LR (p = 0.397). Conclusion. Intralesional curettage of a low-grade CS is associated with an increased risk of LR, but LR does not affect disease-specific survival. Therefore, for low-grade CSs of the hands and feet, surgical management should aim to preserve function. In grade 2 CS, our study did not show any decreased disease-specific survival after recurrence; however, we suggest a more aggressive surgical approach to these tumours to prevent local recurrence, especially in the metacarpal and metatarsal bones. In high-grade tumours, the incidence of progressive disease is high and, therefore, the treatment of the primary tumour should be aggressive where possible, and patients observed closely for the development of metastatic disease. Cite this article: Bone Joint J 2021;103-B(3):562–568

Aims. Dual mobility implants in total hip arthroplasty are designed to increase the functional head size, thus decreasing the potential for dislocation. Modular dual mobility (MDM) implants incorporate a metal liner (e.g. cobalt-chromium alloy) in a metal shell (e.g. titanium alloy), raising concern for mechanically assisted crevice corrosion at the modular liner-shell connection. We sought to examine fretting and corrosion on MDM liners, to analyze the corrosion products, and to examine histologically the periprosthetic tissues. Methods. A total of 60 retrieved liners were subjectively scored for fretting and corrosion. The corrosion products from the three most severely corroded implants were removed from the implant surface, imaged using scanning electron microscopy, and analyzed using Fourier-transform infrared spectroscopy. Results. Fretting was present on 88% (53/60) of the retrieved liners, and corrosion was present on 97% (58/60). Fretting was most often found on the lip of the taper at the transition between the lip and the dome regions. Macrophages and particles reflecting an innate inflammatory reaction to corrosion debris were noted in six of the 48 cases for which periprosthetic tissues were examined, and all were associated with retrieved components that had high corrosion scores. Conclusion. Our results show that corrosion occurs at the interface between MDM liners and shells and that it can be associated with reactions in the local tissues, suggesting continued concern that this problem may become clinically important with longer-term use of these implants. Cite this article: Bone Joint J 2021;103-B(7):1238–1246

Aims. The purpose of this study was to clarify the clinical behaviour, prognosis, and optimum treatment of dedifferentiated low-grade osteosarcoma (DLOS) diagnosed based on molecular pathology. Patients and Methods. We retrospectively reviewed 13 DLOS patients (six men, seven women; median age 32 years (interquartile range (IQR) 27 to 38)) diagnosed using the following criteria: the histological coexistence of low-grade and high-grade osteosarcoma components in the lesion, and positive immunohistochemistry of mouse double minute 2 homolog (MDM2) and cyclin-dependent kinase 4 (CDK4) associated with MDM2 amplification. These patients were then compared with 51 age-matched consecutive conventional osteosarcoma (COS) patients (33 men, 18 women; median age 25 years (IQR 20 to 38)) regarding their clinicopathological features. Results. The five-year overall survival (OAS) rates in the DLOS and COS patients were 85.7% and 77.1% (p = 0.728), respectively, and the five-year progression-free survival (PFS) rates were 57.7% and 44.9% (p = 0.368), respectively. A total of 12 DLOS patients received chemotherapy largely according to regimens for COS. Among the nine cases with a histological evaluation after chemotherapy, eight showed a poor response, and seven of these had a necrosis rate of < 50%. One DLOS patient developed local recurrence and five developed distant metastases. Conclusion. Based on our study of 13 DLOS cases that were strictly defined by histological and molecular means, DLOS showed a poorer response to a standard chemotherapy regimen than COS, while the clinical outcomes were not markedly different. Cite this article: Bone Joint J 2019;101-B:745–752

Aims. The purpose of this study was to describe the effect of histological grade on disease-specific survival in patients with chondrosarcoma. Patients and Methods. A total of 343 patients with a chondrosarcoma were included. The histological grade was assessed on the initial biopsy and on the resection specimen. Where the histology showed a mixed grade, the highest grade was taken as the definitive grade. When only small focal areas showed higher grade, the final grade was considered as both. Results. The concordance between the highest preoperative biopsy grading and the highest final grading of the resection specimen in total was only 43% (146/343). In 102 specimens (30%), a small number of cells or focal areas of higher grade were observed in contrast to the main histology. The disease-specific survival, stratified according to the predominant histological grade, showed greater variation than when stratified according to the highest grade seen in the resection specimen. Conclusion. The diagnostic biopsy in chondrosarcoma is unreliable in assessing the definitive grade and the malignant potential of the tumour. When categorizing the grade of the resection specimen, the prognosis for local recurrence and disease-specific survival should be based on the highest grade seen, even when seen in only a few cells. Cite this article: Bone Joint J 2018;100-B:662–6

Aims. Time to treatment initiation (TTI) is generally defined as the time from the histological diagnosis of malignancy to the initiation of first definitive treatment. There is no consensus on the impact of TTI on the overall survival in patients with a soft-tissue sarcoma. The purpose of this study was to determine if an increased TTI is associated with overall survival in patients with a soft-tissue sarcoma, and to identify the factors associated with a prolonged TTI. Methods. We identified 23,786 patients from the National Cancer Database who had undergone definitive surgery between 2004 and 2015 for a localized high-grade soft-tissue sarcoma of the limbs or trunk. A Cox proportional hazards model was used to examine the relationship between a number of factors and overall survival. We calculated the incidence rate ratio (IRR) using negative binomial regression models to identify the factors that affected TTI. Results. Patients in whom the time to treatment initiation was prolonged had poorer overall survival than those with a TTI of 0 to 30 days. These were: 31 to 60 days (hazard ratio (HR) 1.08, p = 0.011); 61 to 90 days (HR 1.11, p = 0.044); and 91 days (HR 1.22; p = 0.003). The restricted cubic spline showed that the hazard ratio increased substantially with a TTI longer than 50 days. Non-academic centres (vs academic centres; IRR ranging from 0.64 to 0.86; p < 0.001) had a shorter TTI. Those insured by Medicaid (vs private insurance; IRR 1.34), were uninsured (vs private insurance; IRR 1.17), or underwent a transition in care (IRR 1.62) had a longer TTI. Conclusion. A time to treatment initiation of more than 30 days after diagnosis was independently associated with poorer survival. The hazard ratio showed linear increase, especially if the TTI was more than 50 days. We recommend starting treatment within 30 days of diagnosis to achieve the highest likelihood of cure for localized high-grade soft-tissue sarcomas in the limbs and trunk, even when a patient needs to be referred to a specialist centre. Cite this article: Bone Joint J 2021;103-B(6):1142–1149

Aims. Chondrosarcoma is the second most common primary sarcoma of bone: conventional chondrosarcoma accounts for 85% of all cases. Conventional chondrosarcoma may be central or peripheral. Most studies group central and peripheral chondrosarcomas together, although there is growing evidence that their clinical behaviour and prognosis differ. The aims of this study were to analyze any differences in characteristics between central and peripheral chondrosarcomas and to investigate the incidence and role of different syndromes. Methods. Data from two international tertiary referral sarcoma centres between January 1995 and December 2018 were retrospectively reviewed. The study population consisted of 714 patients with surgically treated conventional chondrosarcoma of the pelvis and limbs. Results. In patients with Ollier’s disease and Mafucci’s syndrome, 12/20 (60%) and 2/5 (60%) of malignancies, respectively, were in the limbs, most frequently in the proximal humerus, proximal tibia, and in the hands and feet. In patients with hereditary multiple exostosis (HME), 20/29 (69.0%) of chondrosarcomas were in the pelvis and scapula, specifically in the ilium in 13/29 (44.8%) and the scapula in 3/29 (10.3%). In central chondrosarcoma, survival of patients with Ollier’s disease and non-syndromic patients was the same (p = 0.805). In peripheral chondrosarcoma, survival among HME patients was similar (p = 0.676) in patients with tumours of the pelvis and limbs. Conclusion. Both central and peripheral chondrosarcoma have specific characteristics. HME is frequently seen in patients with a peripheral chondrosarcoma, in whom tumours are commonly located in the ilium and scapula. The incidence of Ollier’s disease is uncommon in patients with a central chondrosarcoma. Disease-specific survival is equal in different subtypes after adjustment for histological grade. The local recurrence-free survival is the same for different locations and subtypes after adjustment for surgical margin. Cite this article: Bone Joint J 2021;103-B(5):984–990

Aims. The aim of this study was to report the outcomes of patients who underwent definitive surgery for secondary chondrosarcomas arising from osteochondromas. Patients and Methods. A total of 51 patients with secondary chondrosarcomas occurring from osteochondromas were reviewed. Median age was 36 years (interquartile range (IQR) 15 to 82). Median follow-up was 6.9 years (IQR 2.8 to 10.6). The pelvis was the most commonly affected site (59%). Histological grades were grade I in 35 (69%), grade II in 13 (25%), and grade III in three patients (6%). Results. Preoperative biopsy histology correctly predicted the final histological grade in 27% of patients. The ten-year disease-specific survival (DSS) for all patients was 89.4%. Local recurrence occurred in 15 patients (29%), more commonly in pelvic tumours (37%) compared with limb tumours (19%). Four patients with pelvic tumours died from progression of local recurrence. No patient with limb tumours died of disease. Wide/radical margin was associated with improved local recurrence-free survival (p = 0.032) and local recurrence was associated with worse DSS (p = 0.005). Conclusion. We recommend that a secondary chondrosarcoma arising from osteochondroma of the pelvis is resected with wide/radical resection margins. The balance between the morbidity of surgery and risk of local recurrence needs to be considered in patients with limb secondary chondrosarcomas. Cite this article: Bone Joint J 2019;101-B:1313–1320

Aims. The STRYDE nail is an evolution of the PRECICE Intramedullary Limb Lengthening System, with unique features regarding its composition. It is designed for load bearing throughout treatment in order to improve patient experience and outcomes and allow for simultaneous bilateral lower limb lengthening. The literature published to date is limited regarding outcomes and potential problems. We report on our early experience and raise awareness for the potential of adverse effects from this device. Methods. This is a retrospective review of prospective data collected on all patients treated in our institution using this implant. We report the demographics, nail accuracy, reliability, consolidation index, and cases where concerning clinical and radiological findings were encountered. There were 14 STRYDE nails implanted in nine patients (three male and six female) between June 2019 and September 2020. Mean age at surgery was 33 years (14 to 65). Five patients underwent bilateral lengthening (two femoral and three tibial) and four patients unilateral femoral lengthening for multiple aetiologies. Results. At the time of reporting, eight patients (13 implants) had completed lengthening. Osteolysis and periosteal reaction at the junction of the telescopic nail was evident in nine implants. Five patients experienced localized pain and swelling. Macroscopic appearances following retrieval were consistent with corrosion at the telescopic junction. Tissue histology was consistent with effects of focal metallic wear debris. Conclusion. From our early experience with this implant we have found the process of lengthening to be accurate and reliable with good regenerate formation and consolidation. Proposed advantages of early load bearing and the ability for bilateral lengthening are promising. We have, however, encountered concerning clinical and radiological findings in several patients. We have elected to discontinue its use to allow further investigation into the retrieved implants and patient outcomes from users internationally. Cite this article: Bone Joint J 2021;103-B(6):1168–1172

Aims. The aim of this study was to analyse a group of patients with non-metastatic Ewing’s sarcoma at presentation and identify prognostic factors affecting the development of local recurrence, in order to assess the role of radiotherapy. Patients and Methods. A retrospective review of all patients with a Ewing’s sarcoma treated between 1980 and 2012 was carried out. Only those treated with chemotherapy followed by surgery and/or radiotherapy were included. Patients were grouped according to site (central or limb) for further analysis of the prognostic factors. Results. A total of 388 patients were included in the study. Of these, 60 (15%) developed local recurrence at a mean median of 27 months (. sd. 24, range 7 to 150) and the five-year local recurrence-free survival (5yrLRFS) was 83%. For central tumours, the size of the tumour and histological response to chemotherapy were found to be significant factors for local recurrence. For limb tumours, local recurrence was affected by intralesional and marginal resections, but not by the histological response to chemotherapy. Radiotherapy in those with a marginal resection reduced the risk of local recurrence (5yrLRFS: 96% versus 81%, p = 0.044). Conclusion. Local recurrence significantly affects the overall survival in patients with a Ewing’s sarcoma. For those with a tumour in a limb, radiotherapy reduced the risk of local recurrence, especially in those with a marginal margin of excision, but the effect in central tumours was less clear. Radiotherapy for those who have had a wide margin of resection does not reduce the risk of local recurrence, regardless of the histological response to chemotherapy. Cite this article: Bone Joint J 2018;100-B: 247–55

Aims. Tenosynovial giant cell tumour (TGCT) is one of the most common soft-tissue tumours of the foot and ankle and can behave in a locally aggressive manner. Tumour control can be difficult, despite the various methods of treatment available. Since treatment guidelines are lacking, the aim of this study was to review the multidisciplinary management by presenting the largest series of TGCT of the foot and ankle to date from two specialized sarcoma centres. Methods. The Oxford Tumour Registry and the Leiden University Medical Centre Sarcoma Registry were retrospectively reviewed for patients with histologically proven foot and ankle TGCT diagnosed between January 2002 and August 2019. Results. A total of 84 patients were included. There were 39 men and 45 women with a mean age at primary treatment of 38.3 years (9 to 72). The median follow-up was 46.5 months (interquartile range (IQR) 21.3 to 82.3). Localized-type TGCT (n = 15) predominantly affected forefoot, whereas diffuse-type TGCT (Dt-TGCT) (n = 9) tended to panarticular involvement. TGCT was not included in the radiological differential diagnosis in 20% (n = 15/75). Most patients had open rather than arthroscopic surgery (76 vs 17). The highest recurrence rates were seen with Dt-TGCT (61%; n = 23/38), panarticular involvement (83%; n = 5/8), and after arthroscopy (47%; n = 8/17). Three (4%) fusions were carried out for osteochondral destruction by Dt-TGCT. There were 14 (16%) patients with Dt-TGCT who underwent systemic treatment, mostly in refractory cases (79%; n = 11). TGCT initially decreased or stabilized in 12 patients (86%), but progressed in five (36%) during follow-up; all five underwent subsequent surgery. Side effects were reported in 12 patients (86%). Conclusion. We recommend open surgical excision as the primary treatment for TGCT of the foot and ankle, particularly in patients with Dt-TGCT with extra-articular involvement. Severe osteochondral destruction may justify salvage procedures, although these are not often undertaken. Systemic treatment is indicated for unresectable or refractory cases. However, side effects are commonly experienced, and relapses may occur once treatment has ceased. Cite this article: Bone Joint J 2021;103-B(4):788–794

Aims. To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod. Methods. This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations. Histological analyses of the biopsies were performed with haematoxylin and eosin staining. Results. Titanium (Ti), vanadium (V), and neodymium (Nd) concentrations in the biopsies taken near the wear marks were found to be significantly higher than those in the control tissue samples. Significantly increased Nd concentrations were also found in the tissues near the barrel of the MCGR. Chronic inflammation was revealed by the histological studies with fibrosis and macrophage infiltration. Black particles were present within the macrophages in the fibrotic tissues. Conclusion. Ti and V were generated mainly at the BO due to metal-on-metal contact, whereas the Nd from the rotor of the MCGR is likely released from the BO during distraction sessions. Phagocytotic immune cells with black particles inside raise concern regarding the long-term implications of metallosis. Cite this article: Bone Joint J 2020;102-B(10):1375–1383

Aims. This study aimed to investigate the role of quantitative histological analysis in the diagnosis of fracture-related infection (FRI). Patients and Methods. The clinical features, microbiology culture results, and histological analysis in 156 surgically treated nonunions were used to stratify the likelihood of associated infection. There were 64 confirmed infected nonunions (one or more confirmatory criteria: pus, sinus, and bacterial growth in two or more samples), 66 aseptic nonunions (no confirmatory criteria), and 26 possibly infected nonunions (pathogen identified from a single specimen and no confirmatory criteria). The histological inflammatory response was assessed by average neutrophil polymorph (NPs) counts per high-power field (HPF) and compared with the established diagnosis. Results. Assuming a cut-off of over five neutrophils per high-power field to diagnose septic nonunion, there was 80% sensitivity and 100% specificity (accuracy 90%). Using a cut-off of no neutrophils seen in any high-power field to diagnose aseptic nonunion, there was a sensitivity of 85% and a specificity of 98% (accuracy 92%). Conclusion. Histology can be used in a bimodal fashion as a diagnostic test for FRI. The presence of more than five NPs/HPF had a positive predictive value for infected nonunion of 100%, while the complete absence of any NPs is almost always indicative of an aseptic nonunion (positive predictive value of 98%). Cite this article: Bone Joint J 2018;100-B:966–72

Aims. To assess the correlation between the histological response to preoperative chemotherapy and event-free survival (EFS) or overall survival (OS) in patients with high-grade localized osteosarcoma. Methods. Out of 625 patients aged ≤ 40 years treated for primary high-grade osteosarcoma between 1997 and 2016, 232 patients without clinically detectable metastases at the time of diagnosis and treated with preoperative high-dose methotrexate, adriamycin and cisplatin (MAP) chemotherapy and surgery were included. Associations of chemotherapy-induced necrosis in the resected specimen and EFS or OS were assessed using Cox model and the Pearson’s correlation coefficients (r). Time-dependent receiver operating characteristic analysis was applied to determine the optimal cut-off value of chemotherapy-induced necrosis for EFS and OS. Results. OS was 74% (95% confidence interval (CI) 67 to 79) at five years. Median chemotherapy-induced necrosis was 85% (interquartile range (IQR) 50% to 97%). In multivariate Cox model, chemotherapy-induced necrosis was significantly associated with EFS and OS (hazard ratio (HR) = 0.99 (95% CI 0.98 to 0.99); p < 0.001 and HR = 0.98 (95% CI 0.97 to 0.99); p < 0.001, respectively). Positive correlation was observed between chemotherapy-induced necrosis and five-year EFS and five-year OS (r = 0.91; p < 0.001, and r = 0.85; p < 0.001, respectively). The optimal cut-off value of chemotherapy-induced necrosis for five-year EFS and five-year OS was 85% and 72%, respectively. Conclusion. Chemotherapy-induced necrosis in the resected specimen showed positive correlation with EFS and OS in patients with high-grade localized osteosarcoma after MAP chemotherapy. In our analysis, optimal cut-off values of MAP chemotherapy-induced necrosis in EFS and OS were lower than the commonly used 90%, suggesting the need for re-evaluation of the optimal cut-off value through larger, international collaborative research. Cite this article: Bone Joint J 2020;102-B(6):795–803

Aims. Survival rates and local control after resection of a sarcoma of the pelvis compare poorly to those of the limbs and have a high incidence of complications. The outcome for patients who need a hindquarter amputation (HQA) to treat a pelvic sarcoma is poor. Our aim was to evaluate the patient, tumour, and reconstructive factors that affect the survival of the patients who undergo HQA for primary or recurrent pelvic sarcoma. Methods. We carried out a retrospective review of all sarcoma patients who had undergone a HQA in a supraregional sarcoma unit between 1996 and 2018. Outcomes included oncological, surgical, and survival characteristics. Results. A total of 136 patients, with a mean age of 51 (12 to 83) underwent HQA, 91 for a bone sarcoma and 45 for a soft tissue sarcoma. The overall survival (OS) after primary HQA for a bone sarcoma was 90.7 months (95% confidence interval (CI) 64.1 to 117.2). In patients undergoing a secondary salvage HQA it was 90.3 months (95% CI 58.1 to 122.5) (p = 0.727). For those treated for a soft tissue sarcoma (STS), the mean OS was 59.3 months (95% CI 31.1 to 88.6) for patients with a primary HQA, and 12.5 months (95% CI 9.4 to 15.5) for those undergoing a secondary salvage HQA (p = 0.038). On multivariate analysis, high histological grade (hazard ratio (HR) 2.033, 95% CI 1.127 to 3.676; p = 0.018) and a diagnosis of STS (HR 1.653, 95% CI 1.027 to 2.660; p = 0.039) were associated with a poor prognosis. The 30-day mortality for patients with curative intent was 0.8% (1/128). For those in whom surgery was carried out with palliative intent it was 33.3% (2/6) (p = 0.001). In total, 53.7% (n = 73) of patients had at least one complication with 23.5% (n = 32) requiring at least one further operation. Direct closure was inferior to flap reconstruction in terms of complete primary wound healing (60.0% (3/5) vs 82.0% (82/100); p = 0.023). Conclusion. In carefully selected patients HQA is associated with satisfactory overall survival, with a low risk of perioperative mortality, but considerable morbidity. However, caution must be exercised when considering the procedure for palliation due to the high incidence of early postoperative mortality. Cite this article: Bone Joint J 2020;102-B(6):788–794

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Implantation of ultra-purified alginate (UPAL) gel is safe and effective in animal osteochondral defect models. This study aimed to examine the applicability of UPAL gel implantation to acellular therapy in humans with cartilage injury.

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The scapula is a rare site for a primary bone tumour. Only a small number of series have studied patient outcomes after treatment. Previous studies have shown a high rate of recurrence, with functional outcomes determined by the preservation of the glenohumeral joint and deltoid. The purpose of the current study was to report the outcome of patients who had undergone tumour resection that included the scapula.

Paediatric bone sarcomas are a dual challenge for orthopaedic surgeons in terms of tumour resection and reconstruction, as it is important to minimize functional and growth problems without compromising survival rates. Cañadell’s technique consists of a Type I epiphysiolysis performed using continuous distraction by an external fixator prior to resection. It was designed to achieve a safe margin due to the ability of the physeal cartilage to be a barrier to tumour spread in some situations, avoiding the need for articular reconstruction, and preserving the growth capacity most of the times. Despite initial doubts raised in the scientific community, this technique is now widely used in many countries for the treatment of metaphyseal paediatric bone sarcomas. This annotation highlights the importance of Cañadell’s work and reviews the experience of applying it to bone sarcoma patients over the last 40 years.

Cite this article: Bone Joint J 2023;105-B(1):11–16.

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The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA).

Aims. Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function. Materials and Methods. A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6). Results. At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate load to failure (p = 0.035), elongation (p = 0.006), and energy absorption (p = 0.022). FiberTape-grafted samples also demonstrated increased bone mineral density in the bone tunnel (p = 0.039). Histological evaluation showed integration of all grafts in the bone tunnels by new bone formation, and limited signs of inflammation overall. A lack of prolonged inflammation in all samples was confirmed by quantification of inflammation biomarkers. However, no regeneration of ligament-like tissue was observed along the suture tape materials. Except for one autograft failure, no adverse events were detected. Conclusion. Our results indicate that FiberTape increases the biomechanical performance of intra-articular ligament reconstructions in a verified rabbit model at eight weeks. Within this period, FiberTape did not adversely affect bone tunnel healing or invoke a prolonged elevation in inflammation. Cite this article: Bone Joint J 2019;101-B:1238–1247

The pre-operative differentiation between enchondroma, low-grade chondrosarcoma and high-grade chondrosarcoma remains a diagnostic challenge. We reviewed the accuracy and safety of the radiological grading of cartilaginous tumours through the assessment of, first, pre-operative radiological and post-operative histological agreement, and second the rate of recurrence in lesions confirmed as high-grade on histology. We performed a retrospective review of major long bone cartilaginous tumours managed by curettage as low grade between 2001 and 2012. A total of 53 patients with a mean age of 47.6 years (8 to 71) were included. There were 23 men and 30 women. The tumours involved the femur (n = 20), humerus (n = 18), tibia (n = 9), fibula (n = 3), radius (n = 2) and ulna (n = 1). Pre-operative diagnoses resulted from multidisciplinary consensus following radiological review alone for 35 tumours, or with the addition of pre-operative image guided needle biopsy for 18. The histologically confirmed diagnosis was enchondroma for two (3.7%), low-grade chondrosarcoma for 49 (92.6%) and high-grade chondrosarcoma for two (3.7%). Three patients with a low-grade tumour developed a local recurrence at a mean of 15 months (12 to 17) post-operatively. A single high-grade recurrence (grade II) was treated with tibial diaphyseal replacement. The overall recurrence rate was 7.5% at a mean follow-up of 4.7 years (1.2 to 12.3). Cartilaginous tumours identified as low-grade on pre-operative imaging with or without additional image-guided needle biopsy can safely be managed as low-grade without pre-operative histological diagnosis. A few tumours may demonstrate high-grade features histologically, but the rates of recurrence are not affected. Cite this article: Bone Joint J 2014; 96-B:1098–105

Prediction tools are instruments which are commonly used to estimate the prognosis in oncology and facilitate clinical decision-making in a more personalized manner. Their popularity is shown by the increasing numbers of prediction tools, which have been described in the medical literature. Many of these tools have been shown to be useful in the field of soft-tissue sarcoma of the extremities (eSTS). In this annotation, we aim to provide an overview of the available prediction tools for eSTS, provide an approach for clinicians to evaluate the performance and usefulness of the available tools for their own patients, and discuss their possible applications in the management of patients with an eSTS.

Cite this article: Bone Joint J 2022;104-B(9):1011–1016.

Periprosthetic joint infection represents a devastating complication after total elbow arthroplasty. Several measures can be implemented before, during, and after surgery to decrease infection rates, which exceed 5%. Debridement with antibiotics and implant retention has been reported to be successful in less than one-third of acute infections, but still plays a role. For elbows with well-fixed implants, staged retention seems to be equally successful as the more commonly performed two-stage reimplantation, both with a success rate of 70% to 80%. Permanent resection or even amputation are occasionally considered. Not uncommonly, a second-stage reimplantation requires complex reconstruction of the skeleton with allografts, and the extensor mechanism may also be deficient. Further developments are needed to improve our management of infection after elbow arthroplasty.

Cite this article: Bone Joint J 2024;106-B(11):1321–1326.

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This study aimed to compare the performance of survival prediction models for bone metastases of the extremities (BM-E) with pathological fractures in an Asian cohort, and investigate patient characteristics associated with survival.

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We performed a systematic literature review to define features of patients, treatment, and biological behaviour of multicentric giant cell tumour (GCT) of bone.

Periprosthetic joint infection (PJI) remains an extremely challenging complication. We have focused on this issue more over the last decade than previously, but there are still many unanswered questions. We now have a workable definition that everyone should align to, but we need to continue to focus on identifying the organisms involved. Surgical strategies are evolving and care is becoming more patient-centred. There are some good studies under way. There are, however, still numerous problems to resolve, and the challenge of PJI remains a major one for the orthopaedic community. This annotation provides some up-to-date thoughts about where we are, and the way forward. There is still scope for plenty of research in this area.

Cite this article: Bone Joint J 2022;104-B(11):1193–1195.

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Venous tumour thrombus (VTT) is a rare finding in osteosarcoma. Despite the high rate of VTT in osteosarcoma of the pelvis, there are very few descriptions of VTT associated with extrapelvic primary osteosarcoma. We therefore sought to describe the prevalence and presenting features of VTT in osteosarcoma of both the pelvis and the limbs.

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Patients with differentiated thyroid carcinomas (DTCs) have a favourable long-term survival. Spinal metastases (SMs) cause a decline in performance status (PS), directly affecting mortality and indirectly preventing the use of systemic therapies. Metastasectomy is indicated, if feasible, as it yields the best local tumour control. Our study aimed to examine the long-term clinical outcomes of metastasectomy for SMs of thyroid carcinomas.

Aim. Mesenchymal stem cells (MSCs) have several properties that may support their use as an early treatment option for osteoarthritis (OA). This study investigated the role of multiple injections of allogeneic bone marrow-derived stem cells (BMSCs) to alleviate the progression of osteoarthritic changes in the various structures of the mature rabbit knee in an anterior cruciate ligament (ACL)-deficient OA model. Materials and Methods. Two months after bilateral section of the ACL of Japanese white rabbits aged nine months or more, either phosphate buffered saline (PBS) or 1 x 10. 6. MSCs were injected into the knee joint in single or three consecutive doses. After two months, the articular cartilage and meniscus were assessed macroscopically, histologically, and immunohistochemically using collagen I and II. Results. Within the PBS injection (control group), typical progressive degenerative changes were revealed in the various knee structures. In the single MSC injection (single group), osteoarthritic changes were attenuated, but still appeared, especially in the medial compartments involving fibrillation of the articular cartilage, osteophyte formation in the medial plateau, and longitudinal tear of the meniscus. In the multiple-injections group, the smoothness and texture of the articular cartilage and meniscus were improved. Histologically, absence or reduction in matrix staining and cellularity were noticeable in the control and single-injection groups, respectively, in contrast to the multiple-injections group, which showed good intensity of matrix staining and chondrocyte distribution in the various cartilage zones. Osteoarthritis Research Society International (OARSI) scoring showed significantly better results in the multiple-injections group than in the other groups. Immunohistochemically, collagen I existed superficially in the medial femoral condyle in the single group, while collagen II was more evident in the multiple-injections group than the single-injection group. Conclusion. A single injection of MSCs was not enough to restore the condition of osteoarthritic joints. This is in contrast to multiple injections of MSCs, which had the ability to replace lost cells, as well as reducing inflammation. Cite this article: Bone Joint J 2019;101-B:824–831

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This study aimed to investigate the clinical characteristics and outcomes associated with culture-negative limb osteomyelitis patients.

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Low-grade central osteosarcoma (LGCOS), a rare type of osteosarcoma, often has misleading radiological and pathological features that overlap with those of other bone tumours, thereby complicating diagnosis and treatment. We aimed to analyze the clinical, radiological, and pathological features of patients with LGCOS, with a focus on diagnosis, treatment, and outcomes.

Aims

Excision of chronic osteomyelitic bone creates a dead space which must be managed to avoid early recurrence of infection. Systemic antibiotics cannot penetrate this space in high concentrations, so local treatment has become an attractive adjunct to surgery. The aim of this study was to present the mid- to long-term results of local treatment with gentamicin in a bioabsorbable ceramic carrier.

Aims. The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model. Materials and Methods. A canine transcortical model was used to evaluate the characteristics of bone ingrowth of Ti6Al4V cylindrical implants fabricated using laser rapid manufacturing (LRM). At four and 12 weeks post-implantation, we performed histological analysis and mechanical push-out testing on three groups of implants: a HA-free control (LRM), LRM with precipitated HA (LRM-PA), and LRM with plasma-sprayed HA (LRM-PSHA). Results. Substantial bone ingrowth was observed in all LRM implants, with and without HA, at both time periods. Bone ingrowth increased from 42% to 52% at four weeks, to 60% to 65% at 12 weeks. Mechanical tests indicated a minimum shear fixation strength of 20 MPa to 24 MPa at four weeks, and 34 MPa to 40 MPa at 12 weeks. There was no significant difference in the amount of bone ingrowth or in the shear strength between the three implant types at either time period. Conclusion. At four and 12 weeks, the 3D printed porous implants exhibited consistent bone ingrowth and high mechanical shear strength. Based on the results of this study, we confirmed the suitability of this novel new additive manufacturing porous material for biological fixation by bone ingrowth. Cite this article: Bone Joint J 2019;101-B(6 Supple B):62–67

Cite this article: Bone Joint J 2024;106-B(1):6–8.

Perilesional changes of chronic focal osteochondral defects were assessed in the knees of 23 sheep. An osteochondral defect was created in the main load-bearing region of the medial condyle of the knees in a controlled, standardised manner. The perilesional cartilage was evaluated macroscopically and biopsies were taken at the time of production of the defect (T0), during a second operation one month later (T1), and after killing animals at three (T3; n = 8), four (T4; n = 8), and seven (T7; n = 8) months. All the samples were histologically assessed by the International Cartilage Repair Society grading system and Mankin histological scores. Biopsies were taken from human patients (n = 10) with chronic articular cartilage lesions and compared with the ovine specimens. The ovine perilesional cartilage presented with macroscopic and histological signs of degeneration. At T1 the International Cartilage Repair Society ‘Subchondral Bone’ score decreased from a mean of 3.0 (. sd. 0) to a mean of 1.9 (. sd. 0.3) and the ‘Matrix’ score from a mean of 3.0 (. sd. 0) to a mean of 2.5 (. sd. 0.5). This progressed further at T3, with the International Cartilage Repair Society ‘Surface’ grading, the ‘Matrix’ grading, ‘Cell Distribution’ and ‘Cell Viability’ grading further decreasing and the Mankin score rising from a mean of 1.3 (. sd. 1.4) to a mean of 5.1 (. sd. 1.6). Human biopsies achieved Mankin grading of a mean of 4.2 (. sd. 1.6) and were comparable with the ovine histology at T1 and T3. The perilesional cartilage in the animal model became chronic at one month and its histological appearance may be considered comparable with that seen in human osteochondral defects after trauma

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

Cite this article: Bone Joint J 2024;106-B(5):425–429.

Tumours of the sacrum are difficult to manage. The sacrum provides the structural connection between the torso and lower half of the body and is subject to both axial and rotational forces. Thus, tumours or their treatment can compromise the stability of the spinopelvic junction. Additionally, nerves responsible for lower limb motor groups as well as bowel, bladder, and sexual function traverse or abut the sacrum. Preservation or sacrifice of these nerves in the treatment of sacral tumours has profound implications on the function and quality of life of the patient. This annotation will discuss current treatment protocols for sacral tumours.

Cite this article: Bone Joint J 2022;104-B(12):1284–1291.

Aims

Due to its indolent clinical behaviour, the treatment paradigm of atypical cartilaginous tumours (ACTs) in the long bones is slowly shifting from intralesional resection (curettage) and local adjuvants, towards active surveillance through wait-and-scan follow-up. In this retrospective cohort study performed in a tertiary referral centre, we studied the natural behaviour of ACT lesions by active surveillance with MRI. Clinical symptoms were not considered in the surveillance programme.

Desmoid tumours are a rare fibroblastic proliferation of monoclonal origin, arising in deep soft-tissues. Histologically, they are characterized by locally aggressive behaviour and an inability to metastasize, and clinically by a heterogeneous and unpredictable course. Desmoid tumours can occur in any anatomical site, but commonly arise in the limbs. Despite their benign nature, they can be extremely disabling and sometimes life-threatening, causing severe pain and functional limitations. Their surgical management is complex and challenging, due to uncertainties surrounding the biological and clinical behaviour, rarity, and limited available literature. Resection has been the first-line approach for patients with a desmoid tumour but, during the last few decades, a shift towards a more conservative approach has occurred, with an initial ‘wait and see’ policy. Many medical and regional forms of treatment are also available for the management of this condition, and others have recently emerged with promising results. However, many areas of controversy remain, and further studies and global collaboration are needed to obtain prospective and randomized data, in order to develop an appropriate shared stepwise approach.

Cite this article: Bone Joint J 2023;105-B(7):729–734.

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The aim of this study is to evaluate the surgical treatment with the best healing rate for patients with proximal femoral unicameral bone cysts (UBCs) after initial surgery, and to determine which procedure has the lowest adverse event burden during follow-up.

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The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

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Endoprosthetic reconstruction following distal femur tumour resection has been widely advocated. In this paper, we present the design of an uncemented endoprosthesis system featuring a short, curved stem, with the goal of enhancing long-term survivorship and functional outcomes.

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The epiphyseal approach to a chondroblastoma of the intercondylar notch of a child’s distal femur does not provide adequate exposure, thereby necessitating the removal of a substantial amount of unaffected bone to expose the lesion. In this study, we compared the functional outcomes, local recurrence, and surgical complications of treating a chondroblastoma of the distal femoral epiphysis by either an intercondylar or an epiphyseal approach.

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The sacroiliac joint (SIJ) is the only mechanical connection between the axial skeleton and lower limbs. Following iliosacral resection, there is debate on whether reconstruction of the joint is necessary. There is a paucity of data comparing the outcomes of patients undergoing reconstruction and those who are not formally reconstructed.

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Revision total hip arthroplasty in patients with Vancouver type B3 fractures with Paprosky type IIIA, IIIB, and IV femoral defects are difficult to treat. One option for Paprovsky type IIIB and IV defects involves modular cementless, tapered, revision femoral components in conjunction with distal interlocking screws. The aim of this study was to analyze the rate of reoperations and complications and union of the fracture, subsidence of the stem, mortality, and the clinical outcomes in these patients.

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The number of revision arthroplasties being performed in the elderly is expected to rise, including revision for infection. The primary aim of this study was to measure the treatment success rate for octogenarians undergoing revision total hip arthroplasty (THA) for periprosthetic joint infection (PJI) compared to a younger cohort. Secondary outcomes were complications and mortality.

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Surgical site infection (SSI) after soft-tissue sarcoma (STS) resection is a serious complication. The purpose of this retrospective study was to investigate the risk factors for SSI after STS resection, and to develop a nomogram that allows patient-specific risk assessment.

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Eccentric reductions may become concentric through femoral head ‘docking’ (FHD) following closed reduction (CR) for developmental dysplasia of the hip (DDH). However, changes regarding position and morphology through FHD are not well understood. We aimed to assess these changes using serial MRI.

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We first sought to compare survival for patients treated surgically for solitary and multiple metastases in the appendicular skeleton, and second, to explore the role of complete and incomplete resection (R0 and R1/R2) in patients with a solitary bony metastasis in the appendicular skeleton.

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Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity.

Aims

The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid.

Aims

The aim of this study was to estimate the 90-day periprosthetic joint infection (PJI) rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA) for osteoarthritis (OA).

Deep-seated lipomas are often atypical histologically and are considered by some to have a high risk of recurrence after excision. We reviewed 215 deep-seated lipomas of the extremities and trunk wall with reference to histology, cytogenetics, clinical features and local recurrence. We classified tumours with atypical features and/or ring chromosomes as atypical lipomas. These were more common in men, larger than ordinary lipomas and more often located in the upper leg. The annual incidence was estimated as ten per million inhabitants and the ratio of atypical to ordinary lipomas was 1:3. In total, six tumours (3%), recurred locally after a median of eight years (1 to 16); of these, four were classified as atypical. The low recurrence rate of deep-seated lipomas of the extremity or trunk wall, irrespective of histological subtype, implies that if surgery is indicated, the tumour may be shelled out, that atypical lipomas in these locations do not deserve the designation well-differentiated liposarcoma, and that routine review after surgery is not required

Aims

Iliosacral sarcoma resections have been shown to have high rates of local recurrence (LR) and poor overall survival. There is also no universal classification for the resection of pelvic sarcomas invading the sacrum. This study proposes a novel classification system and analyzes the survival and risk of recurrence, when using this system.

The LockDown device (previously called Surgilig) is a braided polyester mesh which is mostly used to reconstruct the dislocated acromioclavicular joint. More than 11 000 have been implanted worldwide. Little is known about the tissue reaction to the device nor to its wear products when implanted in an extra-articular site in humans. This is of importance as an adverse immunological reaction could result in osteolysis or damage to the local tissues, thereby affecting the longevity of the implant. We analysed the histology of five LockDown implants retrieved from five patients over the last seven years by one of the senior authors. Routine analysis was carried out in all five cases and immunohistochemistry in one. The LockDown device acts as a scaffold for connective tissue which forms an investing fibrous pseudoligament. The immunological response at the histological level seems favourable with a limited histiocytic and giant cell response to micron-sized wear particles. The connective tissue envelope around the implant is less organised than a native ligament. Cite this article: Bone Joint J 2015;97-B:83–8

Aims

Periprosthetic joint infections (PJIs) with prior multiple failed surgery for reinfection represent a huge challenge for surgeons because of poor vascular supply and biofilm formation. This study aims to determine the results of single-stage revision using intra-articular antibiotic infusion in treating this condition.

We present the histological findings of bone retrieved from beneath the femoral components of failed metal-on-metal hip resurfacing arthroplasties. Of a total of 377 patients who underwent resurfacing arthroplasty, 13 required revision; for fracture of the femoral neck in eight, loosening of a component in three and for other reasons in two. None of these cases had shown histological evidence of osteonecrosis in the femoral bone at the time of the initial implantation. Bone from the remnant of the femoral head showed changes of osteonecrosis in all but one case at revision. In two cases of fracture which occurred within a week of implantation, the changes were compatible with early necrosis of the edge of the fracture. In the remaining six fractures, there were changes of established osteonecrosis. In all but one of the non-fracture cases, patchy osteonecrosis was seen. We conclude that histological evidence of osteonecrosis is a common finding in failed resurfaced hips. Given that osteonecrosis is extensive in resurfaced femoral heads which fail by fracture, it is likely to play a role in the causation of these fractures

Aims

This study compared the cobalt and chromium serum ion concentration of patients treated with two different metal-on-metal (MoM) hinged total knee arthroplasty (TKA) systems, as well as a titanium nitride (TiN)-coated variant.

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Platelet-rich plasma (PRP) intra-articular injections may provide a simple and minimally invasive treatment for early-stage knee osteoarthritis (OA). This has led to an increase in its adoption as a treatment for knee OA, although there is uncertainty about its efficacy and benefit. We hypothesized that patients with early-stage symptomatic knee OA who receive multiple PRP injections will have better clinical outcomes than those receiving single PRP or placebo injections.

Aims

The modified Glasgow Prognostic Score (mGPS) uses preoperative CRP and albumin to calculate a score from 0 to 2 (2 being associated with poor outcomes). mGPS is validated in multiple carcinomas. To date, its use in soft-tissue sarcoma (STS) is limited, with only small cohorts reporting that increased mGPS scores correlates with decreased survival in STS patients.

Aims

The outcome of repeat septic revision after a failed one-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat septic revision after a failed one-stage exchange, and to determine whether the Musculoskeletal Infection Society (MSIS) stage is associated with subsequent infection-related failure.

This study was undertaken to elucidate the mechanism of biological repair at the tendon-bone junction in a rat model. The stump of the toe flexor tendon was sutured to a drilled hole in the tibia (tendon suture group, n = 23) to investigate healing of the tendon-bone junction both radiologically and histologically. Radiological and histological findings were compared with those observed in a sham control group where the bone alone was drilled (n = 19). The biomechanical strength of the repaired junction was confirmed by pull-out testing six weeks after surgery in four rats in the tendon suture group. Callus formation was observed at the site of repair in the tendon suture group, whereas in the sham group callus formation was minimal. During the pull-out test, the repaired tendon-bone junction did not fail because the musculotendinous junction always disrupted first. In order to understand the factors that influenced callus formation at the site of repair, four further groups were evaluated. The nature of the sutured tendon itself was investigated by analysing healing of a tendon stump after necrosis had been induced with liquid nitrogen in 16 cases. A proximal suture group (n = 16) and a partial tenotomy group (n = 16) were prepared to investigate the effects of biomechanical loading on the site of repair. Finally, a group where the periosteum had been excised at the site of repair (n = 16) was examined to study the role of the periosteum. These four groups showed less callus formation radiologically and histologically than did the tendon suture group. In conclusion, the sutured tendon-bone junction healed and achieved mechanical strength at six weeks after suturing, showing good local callus formation. The viability of the tendon stump, mechanical loading and intact periosteum were all found to be important factors for better callus formation at a repaired tendon-bone junction