Periosteal chondroblastoma of the femoral neck: two cases and a review of the literature.

Chondroblastoma is a rare benign cartilaginous tumor mostly confined to the epiphyses and apophyses. Cases outside the epiphyseal region are exceedingly rare. Extramedullary chondroblastomas are exceptional; to our knowledge, only two cases qualified as "periosteal chondroblastoma" have been described in the literature. We report two cases of metaphyseal periosteal chondroblastoma both located on the inferior surface of the femoral neck. Both cases were paucicellular with an unusual dense sclerotic reaction. The diagnosis of chondroblastoma was supported by the expression of histone 3.3, K36M mutant in tumor cells.

Prognostic factors of the synovial sarcoma of the extremities: imaging does matter.

OBJECTIVES: Synovial sarcomas (SS) of the extremities are rare soft tissue sarcomas that are more common in young adults. We deciphered the imaging phenotype of SS with the aim to determine if imaging could provide an incremental value to currently known prognostic factors (PF)-age and histological grade-to predict long-term overall survival (OS). METHODS: This retrospective multicenter study included consecutive pediatric and adult patients with synovial sarcomas of the extremities from December 2002 to August 2020. Inclusion criteria were (i) a follow-up greater than 5 years and (ii) available pre-therapeutic MRI. A subset analysis included MRI and CT-scan. Clinical, pathological, and imaging variables were collected in all patients. The primary endpoint was to evaluate the association of these variables with OS using univariate and multivariate Cox regressions. RESULTS: Out of 428 patients screened for eligibility, 98 patients (mean age: 37.1 ± 15.2 years) were included (MRI: n = 98/98, CT scan: n = 34/98; 35%). The median OS was 75.25 months (IQR = 55.50-109.12) and thirty-six patients (n = 36/98;37%) died during follow-up. The recurrence rate was 12.2% (n =12/98). SS lesions were mostly grade 2 (57/98; 58%). On MRI, SS had a mean long-axis diameter of 67.5 ± 38.3 mm. On CT scan, 44% (15/34) were calcified. Grade (hazard ratio [HR] = 2.71; 95%CI = 1.30-5.66; p = 0.008), size of the lesions evaluated on MRI (HR = 1.02; 95% CI = 1.01-1.03; p < 0.001), and calcifications on CT scan (HR = 0.10; 95% CI = 0.02-0.50; p = 0.005) were independent PF of OS. CONCLUSIONS: This study demonstrated that imaging biomarkers can be used to predict long-term outcome in patients with SS. Strikingly, the presence of calcifications on CT scan is associated with favorable outcome and provides an incremental value over existing PF such as age, grade, and size. KEY POINTS: • Beyond its diagnostic value, MRI is a pre-operative prognostic tool in synovial sarcomas of the extremities since the size of the lesion is an important prognostic factor. • Calcifications on CT scans are independently and significantly associated with prolonged overall survival.

Surgical site infection after pelvic bone and soft tissue sarcoma resection: Risk factors, microbiology, and impact of extended postoperative antibiotic prophylaxis.

BACKGROUND: Pelvic bone and/or soft tissue sarcoma removal surgeries are associated with a high rate of surgical site infection (SSI). The recommended antibiotic prophylaxis (ABP) duration is 24-48 h. We aimed to assess the impact of extended ABP (5 days) on the SSI rate and describe the microbiology of SSI in bone and/or soft tissue pelvic sarcomas. METHODS: We retrospectively included all consecutive patients who underwent pelvic bone and/or soft tissue sarcoma removal surgery between January 2010 and June 2020. RESULTS: We analyzed 146 patients with pelvic bone (45, 31%) or soft tissue (101, 69%). Sixty patients (41%) developed SSI. SSI occurred in 13/28 (46.4%) in the extended ABP group versus 47/118 (39.8%) in the standard group (p = 0.53). In multivariable analysis, risk factors for SSI were surgery duration (OR: 1.94 [1.41-2.92] per h), stay in postoperative ICU for more than 2 days (12.0 [2.8-61.3]), and shred or autologous skin flap (39.3 [5.8-409.5]). Extended ABP was not associated with SSI. SSI were mainly polymicrobial with Enterobacterales (57.4%) and Enterococcus (45%). CONCLUSIONS AND DISCUSSION: Pelvic bone and/or soft tissue sarcoma removal surgery is highly prone to postoperative infection. Extending the ABP to 5 days does not reduce the level of SSI.

Biology and Management of High-Grade Chondrosarcoma: An Update on Targets and Treatment Options.

This review provides an overview of histopathology, clinical presentation, molecular pathways, and potential new systemic treatments of high-grade chondrosarcomas (CS), including grade 2−3 conventional, dedifferentiated, and mesenchymal CS. The diagnosis of CS combines radiological and histological data in conjunction with patient clinical presentations. Conventional CS is the most frequent subtype of CS (85%) and represents about 25% of primary bone tumors in adults; they can be categorized according to their bone location into central, peripheral, and periosteal chondrosarcomas. Central and peripheral CS differ at the molecular level with either IDH1/2 mutations or EXT1/2 mutations, respectively. CDKN2A/B deletions are also frequent in conventional CS, as well as COL2A1 mutations. Dedifferentiated CS develops when low-grade conventional CS transforms into a high-grade sarcoma and most frequently exhibits features of osteosarcoma, fibrosarcoma, or undifferentiated pleomorphic sarcoma. Their molecular characteristics are similar to conventional CS. Mesenchymal CS is a totally different pathological entity exhibiting recurrent translocations. Their clinical presentation and management are different too. The standard treatment of CSs is wide en-bloc resection. CS are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in an attempt to achieve local control in unresectable tumors. Chemotherapy is possibly effective in mesenchymal chondrosarcoma and is of uncertain value in dedifferentiated chondrosarcoma. Due to resistance to standard anticancer agents, the prognosis is poor in patients with metastatic or unresectable chondrosarcomas. Recently, the refined characterization of the molecular profile, as well as the development of new treatments, allow new therapeutic options for these rare tumors. The efficiency of IDH1 inhibitors in other malignancies suggests that these inhibitors will be part of IDH1/2 mutated conventional CS management soon. Other treatment approaches, such as PIK3-AKT-mTOR inhibitors, cell cycle inhibitors, and epigenetic or immune modulators based on improving our understanding of CS molecular biology, are emerging.

Performance of Sonoelastography for predicting malignancy in soft tissue.

BACKGROUND: Separating benign from malignant soft-tissue masses often requires a biopsy. The objective of this study was to assess whether shear-wave elastography (SWE) helped to separate benign from malignant soft-tissue masses. METHODS: In 2015-2016, we prospectively included patients with soft-tissue masses deemed by our multidisciplinary sarcoma board to require a diagnostic biopsy. All patients underwent ultrasonography (US) followed by SWE to measure elasticity. We compared benign and malignant tumors, overall and after separating tumors with vs. without a fatty component. The biopsy findings, and surgical-specimen histology when available, served as the reference standard. RESULTS: We included 136 patients, 99 with non-fatty and 37 with fatty soft-tissue masses. Mean elasticity and tumor-to-fat elasticity ratio (T/F) values were significantly lower for the benign than the malignant soft-tissue masses in the overall cohort (30.9 vs. 50.0 kilopascals (kPa), P = 0.03; and 2.55 vs. 4.30, P = 0.046) and in the non-fatty subgroup (37.8 ± 31.9 vs. 58.9 ± 39.1 kPa, P = 0.049 and 2.89 ± 5.25 vs. 5.07 ± 5.41, P = 0.046). Data for fatty tumors were non relevant due to lack of conclusive results. By receiver operating characteristics curve analysis, a T/F cutoff of 3.5 had 46% sensitivity and 84% specificity for separating benign and malignant soft-tissue masses. CONCLUSIONS: SWE had good specificity and poor sensitivity for separating benign from malignant soft-tissue masses.

Proximal femur versus acetabular extra-articular resection of the hip joint for primary malignant bone tumors: a retrospective comparative review of 33 cases.

INTRODUCTION: Extra-articular resection (EAR) of the hip joint is prone to significant complications and morbidity. Thus, this study evaluates the cumulative incidences and main reasons of reoperation following EAR of primary malignant bone tumors (PMBT) of the hip to determine whether the outcomes are different between EAR of the pelvis and that of the proximal femur. PATIENTS AND METHODS: Thirty-three patients presented with a PMBT of the proximal femur or pelvis were included in this study. Among all PMBTs, 58% originated from the pelvis and 42% were from the proximal femur. Twenty patients had chondrosarcomas (61%), 10 had osteosarcomas (30%), and 3 had sarcomas of another histological subtype (9%). RESULTS: The mean follow-up was of 76 months (range: 24-220 months). The cumulative probabilities of revision for any reason were 52% (95% confidence interval [CI] 30-70%) 5 years after surgery. The 5-year cumulative probabilities of revision were 13% (95% CI 4-27%), 24% (95% CI 10-42%), and 34% (95% CI 14-56%) for mechanical, infectious, and tumoral reasons, respectively. The 5-year cumulative probabilities of revision for any reason were 78% (95% CI 37-94%) and 14% (95% CI 2-38%) for the pelvis and proximal femur, respectively (p = 0.004). Posterior column preservation was significantly associated with more mechanical complications even after adjusting for the resection site (p = 0.043). CONCLUSION: Half of patients undergoing EAR of the hip joint for PMBT of the proximal femur or acetabulum will require another operation. EAR of the pelvis is associated with significantly worse outcome than EAR of the proximal femur.

Management of musculoskeletal tumours of the extremity in low-resource settings.

BACKGROUND: Management of extremity tumor is particularly challenging in low-resource settings where patients are often referred with late presentations. First, diagnostic means are limited, with CT scan, MRI, and pathology usually not being available. Limitations are also related to therapeutic means, as the absence of adjuvant therapy (chemotherapy and radiotherapy) may preclude any improvement in overall survival despite a curative surgical treatment. OBJECTIVE: The authors suggest a kind of "toolbox" combining a diagnostic guide, based on clinical examination and X-rays, and therapeutic advice adapted to this context of care. The objective is to help the surgeon to better categorize the tumor to decide whether or not to operate or act in a relevant way. CONCLUSION: The authors do not aim to provide recommendations but rather an inventory of what the isolated surgeon should know to decide on the best treatment strategy which, however, can only be symptomatic.

Natural history of peripheral nerve schwannomas.

BACKGROUND: Little information about the natural history of peripheral nerve schwannomas exists in the literature. The aim of this study was to determine the natural history of those tumors both in sporadic and schwannomatosis cases to determine their growth rates and patterns. METHODS: In 44 patients from 3 surgical centers, hospital charts, follow-up records, and imaging studies were reviewed. Of these patients, 7 had sporadic schwannomatosis. Histological diagnosis was obtained in 37 patients (84%). Tumor growth rates were determined by calculating the absolute and relative growth rates. RESULTS: On the 47 tumors analyzed, the median tumor size at diagnosis was 1.8 cm3, and the majority of tumors were located in the lower limb (62%). The absolute growth rate ranged from - 1.13 to 23.17 cm3/year (mean, 1.69 cm3/year). Relative annual growth rates ranged from - 9 to 166%/year (mean, 33.9%/year). There was no clear correlation between initial tumor size, age at diagnosis, and tumor growth rate. Six patients (13%) harbored "fast-growing" tumors (absolute growth rate > 2 cm3/year and relative growth rate > 35%/year) while 19% of tumors demonstrate no growth or negative growth. In schwannomatosis patients, each tumor displayed a distinct growth pattern. CONCLUSION: This study confirms the slow-growing nature of most, but not all, peripheral nerve schwannomas. Additional studies are mandatory to explore the environmental factors influencing growth in sporadic cases and the precise growth patterns in schwannomatosis cases to detect the rare cases of malignant transformation and pave the way to the evaluation of future clinical trials.

Higher complications after previous external beam radiation for extremity soft-tissue sarcoma in the surgical treatment of a local recurrence: a comparative retrospective study of one hundred and three patients.

PURPOSE: The use of adjuvant radiation in the treatment of soft-tissue sarcoma (STS) is equivocal in selected cases. Our objective was to compare the short-term outcomes in patients operated on for a local recurrence who had radiation for the primary tumour to those who were spared radiation. METHODS: This was a retrospective study of 103 patients treated for a local recurrence: 48 (47%) with previous radiation and 55 (53%) without. Our primary outcome criterion was to identify the differences in the local treatment provided. Secondary outcomes were the cumulative incidence of a surgical site infection/wound complication (SSI/WC), variables associated with SSI/WC, and local recurrence. RESULTS: Amputation and the incidence of re-operation were significantly more frequent in patients who received previous radiation compared to patients without previous radiation (27% vs 9%, p = 0.02, for amputation; 26% vs 36% at 2 years for SSI/WC, p = 0.049). Multivariable regression models found previous radiation (p = 0.049), arteriopathy (p = 0.012), location at lower limb (p = 0.09), and use of a flap (0.0048) associated with the risk of SSI/WC. CONCLUSIONS: Previous radiation is associated with an increased risk of amputation and reoperation for SSI/WC when treating a local recurrence. This information should be accounted for when deciding for the use of radiation.

Reporting of heterogeneity of treatment effect in cohort studies: a review of the literature.

BACKGROUND: This article corresponds to a literature review and analyze how heterogeneity of treatment (HTE) is reported and addressed in cohort studies and to evaluate the use of the different measures to HTE analysis. METHODS: prospective cohort studies, in English language, measuring the effect of a treatment (pharmacological, interventional, or other) published among 119 core clinical journals (defined by the National Library of Medicine) in the last 16 years were selected in the following data source: Medline. One reviewer randomly sampled journal articles with 1: 1 stratification by journal type: high impact journals (the New England Journal of Medicine, JAMA, LANCET, Annals of Internal Medicine, BMJ and Plos Medicine) and low impact journal (the remaining journals) to identify 150 eligible studies. Two reviewers independently and in duplicate used standardized piloted forms to screen study reports for eligibility and to extract data. They also used explicit criteria to determine whether a cohort study reported HTE analysis. Logistic regression was used to examine the association of prespecified study characteristics with reporting versus not reporting of heterogeneity of treatment effect. RESULTS: One hundred fifty cohort studies were included of which 88 (58%) reported HTE analysis. High impact journals (Odds Ratio: 3.5, 95% CI: 1.78-7.5; P < 0.001), pharmacological studies (Odds Ratio: 0.26, 95% CI: 0.13-0.51; P < 0.001) and studies published after 2014 (Odds Ratio: 0.5, 95% CI: 0.25-0.97; P = 0.004) were associated with more frequent reporting of HTE. 27 (31%) studies which reported HTE used an interaction test. CONCLUSION: More than half cohort studies report some measure of heterogeneity of treatment effect. Prospective cohort studies published in high impact journals, with large sample size, or studying a pharmacological treatment are associated with more frequent HTE reporting. The source of funding was not associated with HTE reporting. There is a need for guidelines on how to perform HTE analyses in cohort studies.

Pelvic reconstructions following peri-acetabular bone tumour resections using a cementless ice-cream cone prosthesis with dual mobility cup.

PURPOSE: Despite numerous reconstructive techniques and prosthetic devices, pelvic reconstructions following peri-acetabular malignant tumours resections are highly challenging. In the present study, we describe our experience with the Integra® (Lépine, Genay, France) ice-cream cone prosthesis in such indications. The objective was to assess the mid-term outcomes of this device. METHODS: Twenty-four patients' chart with peri-acetabular malignant tumours, who underwent types II or II + III peri-acetabular resections according to Enneking and Dunham with subsequent reconstruction using the Integra® prosthesis between February 2009 and February 2015, were reviewed. Seventeen cases were primary surgeries and seven cases were revisions (i.e., failures of previous reconstructions for pelvic tumours). All living patients with the prosthesis implanted were functionally assessed, using the musculoskeletal tumour society (MSTS) and Postel-Merle d'Aubigné (PMA) scores. RESULTS: After a mean follow-up of 49 ± 26 months (range, 8 to 94 months), 21 patients were alive (88%), including 15 patients continuously disease-free (63%). MSTS and PMA scores averaged 72 ± 13% (range, 43 to 87%) and 14.6 ± 2.6 (range, 9 to 18), respectively. Fourteen patients (58%) presented at least one complication during follow-up, including four cases of deep infection (17%), four cases of dislocation (17%), and two mechanical failures (8%). At 5 years, the implant survival rate was 75%. CONCLUSIONS: In comparison to previous reconstructive techniques that we used in similar indications, functional and oncologic outcomes were improved with the Integra® implant. However, as commonly observed in pelvic bone tumour surgery, complication rates remain significant. LEVEL OF EVIDENCE: Therapeutic, Level IV-Retrospective Cases Series.

Using Bayesian statistics to estimate the likelihood a new trial will demonstrate the efficacy of a new treatment.

BACKGROUND: The common frequentist approach is limited in providing investigators with appropriate measures for conducting a new trial. To answer such important questions and one has to look at Bayesian statistics. METHODS: As a worked example, we conducted a Bayesian cumulative meta-analysis to summarize the benefit of patient-specific instrumentation on the alignment of total knee replacement from previously published evidence. Data were sourced from Medline, Embase, and Cochrane databases. All randomised controlled comparisons of the effect of patient-specific instrumentation on the coronal alignment of total knee replacement were included. The main outcome was the risk difference measured by the proportion of failures in the control group minus the proportion of failures in the experimental group. Through Bayesian statistics, we estimated cumulatively over publication time of the trial results: the posterior probabilities that the risk difference was more than 5 and 10%; the posterior probabilities that given the results of all previous published trials an additional fictive trial would achieve a risk difference of at least 5%; and the predictive probabilities that observed failure rate differ from 5% across arms. RESULTS: Thirteen trials were identified including 1092 patients, 554 in the experimental group and 538 in the control group. The cumulative mean risk difference was 0.5% (95% CrI: -5.7%; +4.5%). The posterior probabilities that the risk difference be superior to 5 and 10% was less than 5% after trial #4 and trial #2 respectively. The predictive probability that the difference in failure rates was at least 5% dropped from 45% after the first trial down to 11% after the 13th. Last, only unrealistic trial design parameters could change the overall evidence accumulated to date. CONCLUSIONS: Bayesian probabilities are readily understandable when discussing the relevance of performing a new trial. It provides investigators the current probability that an experimental treatment be superior to a reference treatment. In case a trial is designed, it also provides the predictive probability that this new trial will reach the targeted risk difference in failure rates. TRIAL REGISTRATION: CRD42015024176 .

Optimal post-operative radiation after soft-tissue sarcoma resection is achieved in less than two thirds of cases.

PURPOSE: Local control of soft tissue sarcomas frequently involves adjuvant radiation to the surgical resection. When opting for post-operative radiation, care should be taken that radiation is started within some reasonable time after the surgery. We were interested to the proportion of patients who did not recieve optimal post-operative radiation and the variables associated. METHODS: We retrospectively analyzed a series of 77 patients operated on for an extremity soft-tissue sarcoma and due for post-operative radiotherapy. Patients were considered to have received radiation optimally if radiation was started within 12 weeks of surgery. Variables associated with not receiving radiation optimally were looked for using univariable and multivariable regression models. RESULTS: Overall, 26 patients (34%; 95% CI: 23-45%) did not receive radiation optimally. Twenty (26%) did not start radiation within the 12-weeks mark and six (8%) could not have radiation at all. The main reason identified for not receiving radiation on time was the occurrence of a wound complication (14 (54%) patients). An increased body mass index (OR: 1.14; 95% CI: 1.02-1.26; p = 0.02) and an older age (OR: 1.55; 95% CI: 1.18-2.14; p = 0.04; of note, the OR are for a 10 year change) were significantly associated with not receiving radiation optimally. Patients with a social fragility (p = 0.04), metastatic spread at presentation (p = 0.04), and increased duration of surgery (p = 0.02) were more likely to develop a wound complication. CONCLUSIONS: About 34% of patients do not receive optimal post-operative radiation treatment. Older and obese patients have a higher risk of not receiving radiation optimally. The decision for pre- or post-operative radiation should account for these findings.

Five to thirteen year results of a cemented dual mobility socket to treat recurrent dislocation.

PURPOSE: Dual mobility (DM) socket has been associated with a low rate of dislocation following both primary and revision total hip arthroplasty (THA). However, little is known about the long-term efficiency of DM in the treatment of THA instability. The purpose of this retrospective study was to evaluate the outcome of a cemented DM socket to treat recurrent dislocation after a minimum of five year follow-up. METHODS: The series included 51 patients with a mean age of 71.3 ± 11.5 (range, 41-98) years presenting with recurrent dislocation (mean 3.3). A single DM socket design was used consisting of a stainless steel outer shell with grooves with a highly polished inner surface articulating with a mobile polyethylene component. The femoral head was captured in the polyethylene component using a snap-fit type mechanism, the latter acting as a large unconstrained head inside the metal cup. RESULTS: At the minimum five year follow-up evaluation, 18 of the 51 patients deceased at a mean of 4.8 ± 2.3 years, three were lost to follow-up at a mean of 1.4 years, seven had been revised at a mean of 4.7 ± 3.1 years (range, 1.5-9.1), and the remaining 23 were still alive and did not have revision at a mean of 8.2 ± 2.4 years (range, 5-13 years). Of the seven revision, three were performed for further episodes of dislocation (at the large bearing for one patient and intra-prosthetic for two patients) after a mean 5.9 ± 2.9 years (range, 2.7-9.1), whereas two were performed for late sepsis and two for aseptic loosening of the acetabular component. Radiographic analysis did not reveal any further loosening on the acetabular side. The survival rate of the cup at ten years, using re-dislocation as the end-point, was 86.1 ± 8.4% (95% confidence interval, 69.7-100%). The survival rate of the cup at ten years, using revision for any reason as the end-point, was 75.2 ± 9.3% (95% confidence interval, 56.9-93.5%). CONCLUSION: A cemented dual mobility cup was able to restore hip stability in 94% of patients presenting with recurrent dislocating hips up to 13-year follow-up with none of the complications associated with constrained devices, as mechanical failure occurred in only 3.9% of the patients of this series. The overall reduced survival using revision for any reason as the end-point at ten years was related to this specific patients population that had various co-morbidities.

Validity and Reliability of Intraoperative Radiographs to Assess Leg Length During Total Hip Arthroplasty: Correlation and Reproducibility of Anatomic Distances.

BACKGROUND: Leg length discrepancy after total hip arthroplasty is a frequent complication. The aim of this study was to assess the validity (correlation) and reproducibility (inter-rater agreement) of various intraoperative hip radiographs measures to estimate leg length. METHODS: Patients were included if they were aged 15 years or older; were eligible for a total hip arthroplasty, and were operated in lateral recumbent. An intraoperative hip radiograph was performed with the definitive implants in place. At 6 weeks postoperatively, anteroposterior pelvis radiograph was taken. We used 3 measures to assess leg length: the height from the ischial tuberosity to the lesser trochanter (LTI), the height from the center of femoral head to the greater trochanter (GTC), and to the inferior teardrop (TC). RESULTS: The study group consisted of 71 hips with an average age of 69 years (range, 24-92 years). The correlation was 0.545 (95% CI: 0.35-0.69) for GTC, 0.75 (95% CI: 0.61-0.84) for TC, and 0.70 (95% CI: 0.56-0.80) for LTI. Intraoperative and postoperative measures were statistically different for GTC (<0.0001) and TC (<0.0001), and not significant for LTI (P = .06). Reproducibility of these measures were excellent with intraclass correlation coefficients of 0.977, 0.814, and 0.983 for the GTC, TC, and LTI, respectively. CONCLUSION: None of the parameters used to assess leg-length based on an intraoperative radiograph showed good correlation with the postoperative radiograph.

Effect of anatomic site and irradiation on the rates of revision and infection of allograft-prosthesis composites after resection of a primary bone tumor: a meta-analysis.

INTRODUCTION: Allograft-prosthesis composite reconstruction after resection of a primary bone tumor may have theoretical advantages, such as restoration of bone stock and soft tissue attachments. However, the reported results of APC of different anatomical sites differ widely. We conducted a meta-analysis to estimate the revision and infection rates associated with allograft-prosthesis composite (APC) reconstructions after resection of a primary bone tumor. We looked for variables, such as anatomic sites and irradiation of the allograft, associated with these outcomes. MATERIALS AND METHODS: We searched Medline, EMBASE, and Cochrane Library. The primary outcome was the revision rate, and the secondary outcome was the infection rate. Random effects meta-analyses of single proportions were used to estimate pooled rates of events. Meta-regression models were built to assess the effect of moderators on relevant both outcomes. RESULTS: Thirty-one studies were included: 9 about acetabulum APC, 9 about proximal femur APC, 4 about proximal tibia APC, and 9 about proximal humerus APC. The revision rates ranged from 16 % (95 % CI 10-25 %) for proximal humerus to 38 % (95 % CI 26-52 %) for acetabulum, and were significantly different between anatomic sites (p = 0.028). The infection rates ranged from 8 % (95 % CI 4-16 %) for proximal humerus to 23 % (95 % CI 16-33 %) for proximal tibia and 23 % (95 % CI 15-35 %) acetabulum APCs, and were significantly different between anatomic sites (p = 0.008). Finally, we found that irradiation of the allograft was significantly associated with revision rates (p = 0.033) and infection rates (p < 0.001). CONCLUSIONS: Results of an APC reconstruction after resection of a primary malignant bone tumor vary significantly between anatomic sites and after irradiation of the allograft.

The linea aspera as a rotational landmark: an anatomical MRI-based study.

PURPOSE: The linea aspera can be used as a landmark to assess the rotation of the distal femoral epiphysis when performing an endoprostheses. However, no study has assessed the reliability of this landmark. We therefore asked whether the linea aspera could be used as a rotational landmark for positioning distal femoral knee megaprostheses. MATERIALS: This is an anatomic MRI-based study of 50 femurs (27 subjects). For each femur, multiple axial sections were obtained from the intercondylar line at the knee joint to the lesser trochanter; each axial section was superposed with that where the posterior condyles were seen and the R angle was measured. The R angle is the angle measured medially where the line passing through the linea aspera and the line tangent to the posterior condyles intersects. RESULTS: There were considerable differences between and within subjects with a maximum R angle ranging from 100° to 120°. Regression models showed that the R angle was significantly associated with distance from knee joint and subjects. CONCLUSION: Surgeons should have the R angle measured before performing a distal femoral reconstruction.

Reliability of a new method for evaluating femoral stem positioning after total hip arthroplasty based on stereoradiographic 3D reconstruction.

The goal of this study was to validate a new method for determining femoral stem positioning based on 3D models derived from the EOS biplanar system. Independents observers measured stem anteversion and femoral offset using CT scan and EOS system of 28 femoral stems implanted in composite femurs. In parallel, the same parameters were measured on biplanar lower limb radiographs acquired from 30 patients who had undergone total hip arthroplasty. CT scanner and biplanar X-ray measurements on composite femurs were highly correlated: 0.94 for femoral offset (P < 0.01), 0.98 for stem anteversion (P < 0.01). The inter and intra-observer reproducibility when measuring composite bones was excellent with both imaging modalities as when measuring femoral stem positioning in patients with the biplanar X-ray system.

Peri-prosthetic fractures around tumor endoprostheses: a retrospective analysis of eighteen cases.

PURPOSE: Tumour hip and knee endoprostheses have become the mainstay for reconstruction of patients with bone tumours. Fixation into host bone has improved over time. However, some patients present with a peri-prosthetic fracture over follow-up. The objective of this study was to analyse the mode of presentation and survival of implant after a peri-prosthetic fracture around a tumour endoprosthesis. METHODS: Eighteen peri-prosthetic fractures (17 patients) were included. All patients were treated at a tertiary care center. There were 11 (65%) women; the median age at the time of fracture was 38 years old. All implants were cemented and all knee endoprostheses were fixed-hinge. Twelve (67%) fractures occurred after femoral resection and six (33%) fractures after proximal tibial resection. RESULTS: There were three femoral neck fractures (UCS C), three femoral shaft type C fractures, two femoral shaft type B1, one tibial shaft type B2, three tibial shaft type C, three ankle fractures (UCS C) and three patella fractures (UCS F). Two fractures were treated conservatively and 16 were operated on. Only one patient had the implant revised. There were eight (44%) failures over follow-up; none of the conservative treatment failed. The cumulative probability of failure for any reason was 27% (8-52) and 55% (22-79) at five and ten years, respectively. CONCLUSIONS: Peri-prosthetic fractures around massive endoprostheses are different from that of standard implants. There are more type C fractures; internal fixation is an attractive option at the time of presentation but the risk of revision over follow-up is high and patients should be informed accordingly.

Neither pre-operative education or a minimally invasive procedure have any influence on the recovery time after total hip replacement.

PURPOSE: The purpose of this study was to evaluate pre-operative education versus no education and mini-invasive surgery versus standard surgery to reach complete independence. METHODS: We conducted a four-arm randomized controlled trial of 209 patients. The primary outcome criterion was the time to reach complete functional independence. Secondary outcomes included the operative time, the estimated total blood loss, the pain level, the dose of morphine, and the time to discharge. RESULTS: There was no significant effect of either education (HR: 1.1; P = 0.77) or mini-invasive surgery (HR: 1.0; 95 %; P = 0.96) on the time to reach complete independence. The mini-invasive surgery group significantly reduced the total estimated blood loss (P = 0.0035) and decreased the dose of morphine necessary for titration in the recovery (P = 0.035). CONCLUSIONS: Neither pre-operative education nor mini-invasive surgery reduces the time to reach complete functional independence. Mini-invasive surgery significantly reduces blood loss and the need for morphine consumption.