Can the Cartilaginous Thickness Determine the Risk of Malignancy in Pelvic Cartilaginous Tumors, and How Accurate is the Preoperative Biopsy of These Tumors?

BACKGROUND: Peripheral osteochondral tumors are common, and the management of tumors presenting in the pelvis is challenging and a controversial topic. Some have suggested that cartilage cap thickness may indicate malignant potential, but this supposition is not well validated. QUESTIONS/PURPOSES: (1) How accurate is preoperative biopsy in determining whether a peripheral cartilage tumor of the pelvis is benign or malignant? (2) Is the thickness of the cartilage cap as determined by MRI associated with the likelihood that a given peripheral cartilage tumor is malignant? (3) What is local recurrence-free survival (LRFS), metastasis-free survival (MFS), and disease-specific survival (DSS) in peripheral chondrosarcoma of the pelvis and is it associated with surgical margin? METHODS: Between 2005 and 2022, 289 patients had diagnoses of peripheral cartilage tumors of the pelvis (either pedunculated or sessile) and were treated at one tertiary sarcoma center (the Royal Orthopaedic Hospital, Birmingham, UK). These patients were identified retrospectively from a longitudinally maintained institutional database. Those whose tumors were asymptomatic and discovered incidentally and had cartilage caps ≤ 1.5 cm were discharged (95 patients), leaving 194 patients with tumors that were either symptomatic or had cartilage caps > 1.5 cm. Tumors that were asymptomatic and had a cartilage cap > 1.5 cm were followed with MRIs for 2 years and discharged without biopsy if the tumors did not grow or change in appearance (15 patients). Patients with symptomatic tumors that had cartilage caps ≤ 1.5 cm underwent removal without biopsy (63 patients). A total of 82 patients (63 with caps ≤ 1.5 cm and 19 with caps > 1.5 cm, whose treatment deviated from the routine at the time) had their tumors removed without biopsy. This left 97 patients who underwent biopsy before removal of peripheral cartilage tumors of the pelvis, and this was the group we used to answer research question 1. The thickness of the cartilage cap was recorded from MRI and measuring to the nearest millimeter, with measurements taken perpendicular in the plane that best allowed the greatest measurement. Patient survival rates were assessed using the Kaplan-Meier method with 95% confidence intervals as median observation times to estimate MFS, LRFS, and DSS. RESULTS: Of malignant tumors biopsied, in 49% (40 of 82), the biopsy result was recorded as benign (or was considered uncertain regarding malignancy). A malignant diagnosis was correctly reported in biopsy reports in 51% (42 of 82) of patients, and if biopsy samples with uncertainty regarding malignancy were excluded, the biopsy identified a lesion as being malignant in 84% (42 of 50) of patients. The biopsy results correlated with the final histologic grade as recorded from the resected specimen in only 33% (27 of 82) of patients. Among these 82 patients, 15 biopsies underestimated the final histologic grade. The median cartilage cap thickness for all benign osteochondromas was 0.5 cm (range 0.1 to 4.0 cm), and the median cartilage cap thickness for malignant peripheral chondrosarcomas was 8.0 cm (range 3.0 to 19 cm, difference of medians 7.5 cm; p < 0.01). LRFS was 49% (95% CI 35% to 63%) at 3 years for patients with malignant peripheral tumors with < 1-mm margins, and LRFS was 97% (95% CI 92% to 100%) for patients with malignant peripheral tumors with ≥ 1-mm margins (p < 0.01). DSS was 100% at 3 years for Grade 1 chondrosarcomas, 94% (95% CI 86% to 100%) at 3 years for Grade 2 chondrosarcomas, 73% (95% CI 47% to 99%) at 3 and 5 years for Grade 3 chondrosarcomas, and 20% (95% CI 0% to 55%) at 3 and 5 years for dedifferentiated chondrosarcomas (p < 0.01). DSS was 87% (95% CI 78% to 96%) at 3 years for patients with malignant peripheral tumors with < 1-mm margin, and DSS was 100% at 3 years for patients with malignant peripheral tumors with ≥ 1-mm margins (p = 0.01). CONCLUSION: A thin cartilage cap (< 3 cm) is characteristic of benign osteochondroma. The likelihood of a cartilage tumor being malignant increases after the cartilage cap thickness exceeds 3 cm. In our experience, preoperative biopsy results were not reliably associated with the final histologic grade or malignancy, being accurate in only 33% of patients. We therefore recommend observation for 2 years for patients with pelvic osteochondromas in which the cap thickness is < 1.5 cm and there is no associated pain. For patients with tumors in which the cap thickness is 1.5 to 3 cm, we recommend either close observation for 2 years or resection, depending on the treating physician's decision. We recommend excision in patients whose pelvic osteochondromas show an increase in thickness or pain, preferably before the cartilage cap thickness is 3 cm. We propose that surgical resection of peripheral cartilage tumors in which the cartilage cap exceeds 3 cm (aiming for clear margins) is reasonable without preoperative biopsy; the role of preoperative biopsy is less helpful because radiologic measurement of the cartilage cap thickness appears to be accurately associated with malignancy. Biopsy might be helpful in patients in whom there is diagnostic uncertainty or when confirming the necessity of extensive surgical procedures. Future studies should evaluate other preoperative tumor qualities in differentiating malignant peripheral cartilage tumors from benign tumors. LEVEL OF EVIDENCE: Level III, diagnostic study.

Early radiographic osseointegration of a novel highly porous 3D-printed titanium collar for megaprostheses compared to a previous generation smooth HA-coated collar.

PURPOSE: Extracortical osseointegration at the collar-bone interface of megaprostheses is associated with improved implant stability, lower rates of stem fracture and loosening. The use of hydroxy-apatite (HA-) coated collars showed mixed results in previously published reports. A novel collar system has recently become available utilizing additive manufacturing technology to create a highly porous titanium collar with a calcium-phosphate coated surface. The aim of this study was to evaluate our early experience with this novel collar and compare it to the previously used HA-coated model. METHODS: Twenty patients who underwent megaprostheses implantation utilizing the novel collar system were case matched to 20 patients who had previously undergone a HA-coated collar. A minimum radiological follow-up of three months was available in all included patients. Osseointegration was evaluated using postoperative plain radiographs in two planes based on a previously published semi-quantitative score. RESULTS: Compared to the HA-coated collar the use of the novel highly porous collar was associated with a higher proportion of cases demonstrating osseointegration at the bone-collar interface (80% vs. 65%). Application of the highly porous collar led to a significantly shortened time to reach the final ongrowth score (173 ± 89 days vs. 299 ± 165 days, p < 0.05). At one year follow-up, 90% of the novel collars had reached their final osseoingration grade compared to 50% in the HA-coated collar group (p < 0.001). Radiological osseointegration was seen in 71% for highly porous collars where the indication was revision arthroplasty, compared to 27% in reported in the literature. CONCLUSION: These results indicate more reliable and accelerated osseointegration at the bone-collar interface of a novel highly porous collar system compared to a previously used HA-coated collar. Further studies are warranted to confirm these findings.

Surgical treatment of skeletal metastases in proximal tibia: a multicenter case series of 74 patients.

Background and purpose - The proximal tibia is a rare site for metastatic bone disease and is a challenging anatomical site to manage due to the proximity to the knee joint and poor soft tissue envelope. We investigated implant survival and complications of different surgical strategies in the treatment of proximal tibia pathological fractures.Patients and methods - The study comprised a 4 medical center, retrospective analysis of 74 patients surgically treated for metastases of the proximal tibia. Patient records were reviewed to identify outcome, incidence, and type of complications as well as contributing factors.Results - Reconstruction techniques comprised cement-augmented osteosynthesis (n = 33), tumor prosthesis (n = 31), and total knee arthroplasty with long cemented stems (n = 10). Overall implant survival was 88% at 6 months and 1 year, and 67% at 3 years. After stratification by technique, the implant survival was 82% and 71% at 1 and 3 years with tumor prosthesis, 100% at 1 and 3 years with total knee arthroplasty, and 91% at 1 year and 47% at 3 years with osteosynthesis. Preoperative radiotherapy decreased implant survival. Complications were observed in 19/74 patients. Treatment complications led to amputation in 5 patients.Interpretation - In this study, the best results were seen with both types of prothesis reconstructions, with good implant survival, when compared with treatment with osteosynthesis. However, patients treated with tumor prosthesis showed an increased incidence of postoperative infection, which resulted in poor implant survival. Osteosynthesis with cement is a good alternative for patients with short expected survival whereas endoprosthetic replacement achieved good medium-term results.

Is Microscopic Vascular Invasion in Tumor Specimens Associated with Worse Prognosis in Patients with High-grade Localized Osteosarcoma?

BACKGROUND: Other than metastases at diagnosis and histological response to preoperative chemotherapy, there are few reliable predictors of survival in patients with osteosarcoma. Microscopic vascular invasion (MVI) has been identified in the resection specimens of patients with osteosarcoma. However, it is unknown whether the MVI in resected specimens is associated with worse overall survival and higher cumulative incidence of local recurrence or metastasis in a large cohort of patients younger than 40 years with high-grade localized osteosarcoma. QUESTIONS/PURPOSES: (1) Is MVI associated with worse overall survival and higher cumulative incidence of events (local recurrence or metastasis) in patients younger than 40 years with high-grade localized osteosarcoma? (2) What clinical characteristics are associated with MVI in patients with high-grade localized osteosarcoma? METHODS: A total of 625 patients younger than 40 years with primary high-grade osteosarcoma between 1997 and 2016 were identified in our oncology database. We included patients younger than 40 years with primary high-grade osteosarcoma who underwent definitive surgery and preoperative and postoperative chemotherapy. The minimum follow-up period was 2 years after treatment. Patients with the following were excluded: metastasis at initial presentation (21%, n = 133), progression with preoperative chemotherapy precluding definitive surgery (6%, n = 38), surgery at another unit (2%, n = 13), lost to follow-up before 2 years but not known to have died (3%, n = 18), and death related to complications of preoperative chemotherapy (1%, n = 4). A retrospective pathologic and record review was conducted in the remaining 419 patients. The median follow-up period was 5 years (interquartile range [IQR] 3 to 9 years). The overall survival of the entire group (n = 419) was 67% [95% CI 63 to 72] at 5 years. Of the 419 patients, 10% (41) had MVI in their resection specimens. The Kaplan-Meier method was used to estimate overall survival. The cumulative incidence of events captured the first event of either metastasis or local recurrence. This analysis was completed with a competing risk framework: deaths without evidence of local recurrence or metastasis were regarded as a competing event. Clinical and histological variables (sex, age, tumor site, tumor largest dimension, surgical margin, chemotherapy-induced necrosis, type of surgery, histologic type of tumor, type of chemotherapy regimen, pathologic fracture, and MVI) were evaluated using the log-rank test or Gray test in the univariate analyses and Cox proportional hazard model or Fine and Gray model in the multivariate analyses. RESULTS: After adjusting for other factors, multivariate analyses showed that the presence of MVI in resection specimens was associated with worse overall survival and higher cumulative incidence of event (hazard ratio 1.88 [95% CI 1.22 to 2.89]; p = 0.004 and HR 2.33 [95% CI 1.56 to 3.49]; p < 0.001, respectively). A subgroup analysis demonstrated that the relationship between MVI and survival applied only to patients with a poor response to chemotherapy (less than 90% necrosis; overall survival at 5 years, MVI [+] = 24% [95% CI 11 to 39] versus MVI [-] = 60% [95% CI 52 to 66]; p < 0.001 and cumulative incidence of events at 5 years, MVI [+] = 86% [95% CI 68 to 94] versus MVI [-] = 54% [95% CI 46 to 61]; p < 0.001). The MVI (+) group had a higher proportion of patients with a poor response to chemotherapy (85% [35 of 41] versus 53% [201 of 378]; p < 0.001), involved margins (15% [6 of 41] versus 5% [18 of 378]; p = 0.021), and limb-ablative surgery (37% [15 of 41] versus 21% [79 of 378]; p = 0.022) than the MVI (-) group did. CONCLUSIONS: MVI is associated with lower overall survival and higher cumulative incidence of local recurrence or metastasis, especially in patients with a poor histologic response to preoperative chemotherapy. Future studies in patients treated for osteosarcoma should consider this observation when planning new trials. LEVEL OF EVIDENCE: Level III, therapeutic study.

Surgical treatment for pelvic Ewing sarcoma: What is a safe and functional acetabular reconstruction when combined with modern multidisciplinary treatments?

PURPOSE: The purpose of this study was to clarify which local treatment is oncologically and functionally effective in pelvic Ewing sarcoma (ES). METHODS: A consecutive series of patients who underwent pelvic resections and acetabular reconstructions after chemotherapy between 1986 and 2016 at a supra-regional center were evaluated. RESULTS: The cohort consisted of 35 patients. The 5-year overall survival (OS) and local recurrence-free survival (LRFS) was 61% and 72%, respectively. Preoperative radiotherapy (RT) and surgery provided an excellent/good histological response in 92% and achieved significantly better OS (5 years, 64%) and LRFS (5 years, 100%) than surgery alone or surgery with postoperative RT. The Musculoskeletal Tumor Society functional scores were significantly better in patients with hip transposition than those with structural reconstructions (74% vs 57%; P = .031) using custom-made prostheses, irradiated autografts, and ice-cream cone prostheses. These scores were significantly lower if patients had deep infection (P = .035), which was the most common complication (28%) in structural reconstructions but did not occur in hip transposition even when performed after preoperative RT. CONCLUSION: Acetabular reconstruction with hip transposition resulted in no deep infection and superior function in patients with pelvic ES even when combined with preoperative RT, which improved tumor necrosis and rate of local control and survival.

Hypotensive Epidural Anesthesia Reduces Blood Loss in Pelvic and Sacral Bone Tumor Resections.

BACKGROUND: Resection of pelvic and sacral tumors can cause severe blood loss, complications, and even postoperative death. Hypotensive epidural anesthesia has been used to mitigate blood loss after elective arthroplasty, but to our knowledge, it has not been studied as an approach that might make resection of pelvic and sacral tumors safer. QUESTIONS/PURPOSES: The purposes of this study were (1) to compare the blood loss and blood product use for patients undergoing pelvic and sacral tumor surgery under standard anesthesia or hypotensive epidural anesthesia; (2) to assess the frequency of end-organ damage with the two techniques; and (3) to compare 90-day mortality between the two techniques. METHODS: Between 2000 and 2014, 285 major pelvic and sacral resections were performed at one center. A total of 174 (61%) had complete data sets for analysis of blood loss, transfusion use, complications, and mortality at 90 days. Of those, 102 (59%) underwent hypotensive epidural anesthesia, whereas the remainder received standard anesthetic care. The anesthetic approach was determined by the anesthetists in charge of the case with hypotensive epidural anesthesia exclusively performed by one of two subspecialty trained anesthetists as their routine for major pelvic or sacral surgery. The groups were comparable in terms of potential confounding variables such as age, gender, tumor volume, and operation performed. Hypotensive epidural anesthesia was defined as a technique using an extensive epidural block up to T2-3 dermatome, peripherally administered low-concentration intravenous adrenaline infusion, and using unimpeded spontaneous respiration to achieve controlled hypotension, precise rate control of the heart, and enhanced velocity of venous return, all aggregated thus to minimize blood loss during pelvic surgery while preserving vital perfusion. The groups were assessed for perioperative blood loss calculated from pre- and postsurgery hemoglobin and transfusion use as well as postoperative complications, morbidity, and mortality at 90 days. RESULTS: There was less mean blood loss in the hypotensive epidural anesthesia group (1457 mL, SD 1721, 95% confidence interval [CI], 1114-1801 versus 2421 mL, SD 2297, 95% CI, 1877-2965; p = 0.003). Patients in the hypotensive epidural anesthesia group on average received fewer packed red cell transfusions (2.7 units, SD 2.9, 95% CI, 2.1-3.2 versus 3.9 units, SD 4.4, 95% CI, 2.9-5.0; p = 0.03). There were no differences in the proportions of patients experiencing end-organ injury (7%, n = seven of 102 versus 6%, n = four of 72; p = 0.72). With the numbers available, there was no difference in 90-day mortality rate between groups (1.9%, n = two of 102 versus 1.3%, n = one of 72; p = 0.77). CONCLUSIONS: We found that hypotensive epidural anesthesia resulted in less blood loss, fewer transfusions, and no apparent increase in serious complications in pelvic and sacral tumor surgery performed in the setting of a high-volume tertiary sarcoma referral hospital. We recommend that further collaborative studies be undertaken to confirm our results with hypotensive epidural anesthesia in surgery for pelvic tumors. LEVEL OF EVIDENCE: Level III, therapeutic study.

The Wagner Cone Stem for the Management of the Challenging Femur in Primary Hip Arthroplasty.

BACKGROUND: Splined conical stems offer design features that facilitate their use in the misshapen, dysplastic proximal femur. METHODS: This study assessed the survivorship of a conical prosthesis when applied to secondary coxarthrosis because of a range of pathologies. Fifty-one prostheses were implanted in 50 patients with a mean age of 50 (range, 15-80) and a median follow-up of 34 months (range, 24-73 months). Indications for the stem included developmental (36), neuromuscular (7), post-traumatic or surgical (7), and inflammatory conditions (1). Survivorship, functional outcome (WOMAC [Western Ontaria and McMaster University Osteoarthrits Index], Oxford Hip Score, and UCLA [University of California Los Angeles]), health status (short form-12 [SF-12]), satisfaction, and osseointegration were determined. RESULTS: Survivorship for aseptic loosening was 100% at 2 years and 98.04% for septic revision. Eight patients required reoperation, 4 for instability, and 1 each for infection, impingement, adverse reaction to metal debris, and pelvic insufficiency fracture. The mean WOMAC score was 85 (standard deviation [SD], 18), the mean Oxford Hip Score 84 (SD, 18), the mean physical SF-12 score was 48.3 (SD, 8.6), and the mean mental SF-12 was 53.7 (SD, 9.2), the mean satisfaction score was 91.5 (SD, 3.9), and the mean UCLA was 6 (SD, 1.6). All femoral components demonstrated osseointegration. CONCLUSION: The cone femoral prosthesis demonstrates excellent early survival and osseointegration when applied to the challenging femur. Because of these encouraging results, we recommend this prosthesis be considered for the small, abnormal femur in primary hip arthroplasty.

Can a Silver-Coated Arthrodesis Implant Provide a Viable Alternative to Above Knee Amputation in the Unsalvageable, Infected Total Knee Arthroplasty?

BACKGROUND: In the unsalvageable, infected total knee arthroplasty, knee arthrodesis is one treatment option with lower reported reinfection rates compared with repeated 2-stage revision and improved function compared with amputation. One possible method for reducing incidence of recurrent infection treated by arthrodesis is the use of a silver-coated implant. We report our experience of silver-coated arthrodesis nails used for managing infected revision arthroplasty. We primarily assess the rate of reinfection and rate of amputation and report functional outcome measures. METHODS: Retrospective analysis of all patients undergoing knee arthrodesis with a silver-coated arthrodesis nail between 2008 and 2014. Patient-reported data were recorded prearthrodesis and postarthrodesis (Oxford Knee Score and Short Form-36) as well as evidence of recurrent of infection, subsequent surgery, and the necessity for amputation. RESULTS: Eight patients underwent arthrodesis using the silver-coated arthrodesis nail. Mean duration of follow-up was 16 months (5-35 months). At the point of follow-up, there were no amputations, deaths, or implant revisions. One case of recurrent infection was successfully treated with washout and debridement. The mean prearthrodesis and postarthrodesis Oxford Knee Score difference was +8.9 points (P = .086) with significantly improved pain (P = .019), night pain (P = .021), and ease of standing (P = .003). CONCLUSION: Arthrodesis of the knee using a silver-coated intramedullary device is successful in eradicating infection and allowing limb conservation. Where infection does recur, this can be successfully treated with implant retention. The use of a silver-coated arthrodesis nail should be considered as an alternative to amputation for patients with a multiply revised and infected total knee arthroplasty.

Comparison of Acetabular Bone Resection, Offset, Leg Length and Post Operative Function Between Hip Resurfacing Arthroplasty and Total Hip Arthroplasty.

Controversy exists regarding the amount of acetabular bone resection, biomechanics and function of patients receiving either total hip arthroplasty (THA) or hip resurfacing arthroplasty (HRA). A cohort of patients undergoing 36 mm ceramic-on-ceramic THA (89) or metal-on-metal HRA (86) were compared. No difference was observed when the ratio of native femoral head size was compared to the implanted acetabular component size (1.15 ± 0.1 HRA c.f. 1.13 ± 0.1 THA). No difference was observed in acetabular offset, vertical centre of rotation or function (OHS mean 47 in both groups) but leg length discrepancy (1.8 mm c.f. 5.5 mm) and femoral offset did differ (0.6 mm c.f. 4.1 mm). This demonstrates that 36 mm ceramic-on-ceramic THA is not associated with more bone resection than HRA and achieves equivalent function whilst avoiding the problems of metal-on-metal bearings.

Early death following primary total hip arthroplasty.

This study aims to describe the timing, cause of death, and excess surgical mortality associated with primary total hip arthroplasty when compared to a population awaiting primary total hip arthroplasty. Mortality rates were calculated at cutoffs of 30 and 90 days post-operation or following the addition to the waiting list. Cause of death was recorded from the death certificate. An excess surgical mortality of 0.256% at 30 days (P = 0.002) and 0.025% at 90 days post-operation (P = 0.892), unaffected by age or gender, was seen with myocardial infarction and pneumonia the cause of death in the majority of cases. By using a more appropriate control population, an excess surgical mortality at 30 days post-operation is demonstrated; the effect diminishes at 90 days post-operation.

Cement in cement revision of the femoral component using a collarless triple taper: a midterm clinical and radiographic assessment.

This study describes the midterm clinical and radiological results of the cement in cement technique for the femur using a collarless triple taper. Radiographic assessment was made retrospectively from 44 patients at two time points. Clinical outcomes included the Oxford Hip Score, EQ5D and Self Reported Patient Satisfaction Scale. Implant and patient survival were also recorded. The mean clinical follow up period was 5years 3months and the radiological follow up 2years 10months. The mean OHS was 34, the mean EQ5D 0.814 and the mean SAPS 94. Kaplan-Meier survival with revision, as the end point was 95.2% at 11years with a survivorship of 76.5% with death as the end point. Cement in cement revision using a collarless triple tapered stem demonstrates promising results both clinically and radiologically at midterm follow up.

Chondrosarcoma of the Femur: Is Local Recurrence Influenced by the Presence of an Extraosseous Component?

BACKGROUND: Chondrosarcoma (CS) is the second most common surgically treated primary malignancy of the bone. The current study explored the effect of the margin and extraosseous tumor component in CS in the femur on local recurrence (LR), LR-free survival (LRFS), and disease-specific survival (DSS). METHODS: Among 202 patients, 115 were in the proximal extremity of the femur, 4 in the corpus of the femur, and 83 in the distal extremity of femur; 105 patients had an extraosseous tumor component. RESULTS: In the Kaplan-Meier analysis, factors significant for decreased LRFS were the extraosseous tumor component (p < 0.001), extraosseous tumor component arising from the superior aspect (p < 0.001), histological grade (p = 0.031), and narrow surgical margin < 3 mm (p < 0.001). Factors significantly affecting DSS were the histological grade (p < 0.001), extraosseous component (p < 0.001), LR (p < 0.001), metastases (p < 0.001), and surgical margin (p < 0.001). CONCLUSIONS: In CS of the femur, the presence of an extraosseous tumor component has a predictive role in LRFS, and extraosseous tumor component arising from the superior aspect was significant for decreased LRFS. Wide margins were more commonly achieved when the tumor had only an intraosseous component, and the rate of LR was significantly higher in cases with an extraosseous tumor component. When the extraosseous component arose from the superior aspect of the femur, LR occurred more frequently despite achieving adequate margins.

Pelvic bone sarcomas, prognostic factors, and treatment: A narrative review of the literature.

Primary sarcomas of bone are rare malignant mesenchymal tumors. The most common bone sarcomas are osteosarcoma, Ewing's sarcoma, and chondrosarcoma. The prognosis has improved over the years, but bone sarcomas are still life-threatening tumors that need a multidisciplinary approach for diagnosis and treatment. Bone sarcomas arising in the pelvis present a unique challenge to orthopedic oncologists due to the absence of natural anatomical barriers, the close proximity of vital neurovascular structures, and the high mechanical demands placed on any pelvic reconstruction following the excision of the tumor. While radiotherapy has an important role especially in Ewing's sarcoma and chemotherapy for both Ewing's sarcoma and osteosarcoma, surgery remains the main choice of treatment for all three entities. While external hemipelvectomy has remained one option, the main aim of surgery is limb salvage. After complete tumor resection, the bone defect needs to be reconstructed. Possibilities to reconstruct the defect include prosthetic or biological reconstruction. The method of reconstruction is dependent on the location of tumor and the surgery required for its removal. The aim of this article is to give an insight into pelvic bone sarcomas, their oncological and surgical outcomes, and the options for treatment based on the authors' experiences.

Accuracy of MRI scans in predicting intra-articular joint involvement in high-grade sarcomas around the knee.

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.

Intraosseous conventional central chondrosarcoma does not metastasise irrespective of grade in pelvis, scapula and in long bone locations.

Background: Histological grade has been regarded as the most important prognostic factor in conventional central chondrosarcoma. To evaluate whether the presence of an extraosseous tumour component is associated with a decreased metastasis-free survival or disease-specific survival and alternatively to develop a simple prognostic and clinical decision-making tool. Material and methods: We searched two prospectively maintained international sarcoma centre databases for primary non metastatic central conventional chondrosarcomas of all grades in pelvis, scapula or long bone location, undergoing curative treatment, diagnosed between 2000 and 2020. Pre-treatment MRI scans were reviewed for the presence of an extraosseous mass. The metastasis-free survival (MFS) and disease-specific survival (DSS) were estimated by the Kaplan-Meier method from surgery to event, death or last follow-up. Results: 336 patients were identified between 2000 and 2020, undergoing surgical treatment for conventional central chondrosarcoma. 111 patients (33 %) had grade 1 tumours, 149 patients (44 %) had grade 2, and 76 patient (23 %) had grade 3 chondrosarcomas determined as the highest grade in the final resected specimen. An extraosseous soft tissue component was more frequent in higher grade tumours (p < 0.001) and present in 200 cases (60 %). None of the patients with an intraosseous tumour developed metastases or died of the disease. For patients with extraosseous tumour component, MFS was 92 % (95 % CI, 96-100) at 2-years and 74 % (95 % CI, 67-81) at 10-years and DSS was 91 % (95 % CI, 87-95) at 2-years and 75 % (95 % CI, 68-82) at 10-years. The MFS and DSS was significantly different (p < 0.001) for those patients with or without an extraosseous tumour component, irrespective of grade or anatomical location. Discussion: The results of this study has shown that the metastatic potential of intraosseous conventional central chondrosarcoma is negligible. The presence of an extraosseous soft tissue component may be used for prognostication and to guide treatment pathways for patients with central cartilage tumours.

Chondrosarcoma of the Proximal Humerus: Does the Margin Affect Survival?

Chondrosarcoma (CS) is the second most common primary malignant bone tumour and, in the absence of reliable chemotherapy and radiotherapy, is effectively a surgical disease. Overall disease specific survival (DSS) is affected by tumour grade, whilst resection margin contributes to local recurrence free survival (LRFS). The aim of this study was to investigate factors that affect the local and systemic prognoses for conventional central CSs arising from the proximal humerus. A multi-centre, retrospective study from three international collaborative sarcoma centres identified 110 patients between 1995 and 2020 undergoing treatment for a conventional central CS of the proximal humerus; 58 patients (53%) had a grade 1 tumour, 36 (33%) had a grade 2 tumour, and 16 patients (13%) had a grade 3 CS. The mean age of patients was 50 years (range 10-85). The incidence of local recurrence (LR) was 9/110 (8.2%), and the disease specific mortality was 6/110 (5.5%). The grade was a statistically significant factor for LRFS (p < 0.001). None of the grade 1 tumours developed LR. The DSS was affected by the grade (p < 0.001) but not by the LR (p = 0.4). Only one patient with a grade 2 tumour died from the disease. The proximal humeral grade 1 CS behaved as a benign tumour, having no cases of LR nor death due to disease. Grade 2 CSs of the proximal humerus behaved in a more indolent way when compared with comparable grade tumours elsewhere in the appendicular skeleton, being locally aggressive with a higher LR rate than grade 1 CSs but still having very low mortality and a high rate of DSS. The LR in grade 2 CSs did not affect the DSS; therefore, surgical management in proximal humeral grade 2 CSs should have a greater emphasis on preserving function whilst maintaining an adequate margin for resection. The proximal humeral grade 3 CS was, as elsewhere in the skeleton, an aggressive, high-grade tumour. Therefore, surgical management should include en bloc resection with clear margins to avoid LR.

Acetabular complications are the most common cause for revision surgery following proximal femoral endoprosthetic replacement : what is the best bearing option in the primary and revision setting?

AIMS: Proximal femoral endoprosthetic replacements (PFEPRs) are the most common reconstruction option for osseous defects following primary and metastatic tumour resection. This study aimed to compare the rate of implant failure between PFEPRs with monopolar and bipolar hemiarthroplasties and acetabular arthroplasties, and determine the optimum articulation for revision PFEPRs. METHODS: This is a retrospective review of 233 patients who underwent PFEPR. The mean age was 54.7 years (SD 18.2), and 99 (42.5%) were male. There were 90 patients with primary bone tumours (38.6%), 122 with metastatic bone disease (52.4%), and 21 with haematological malignancy (9.0%). A total of 128 patients had monopolar (54.9%), 74 had bipolar hemiarthroplasty heads (31.8%), and 31 underwent acetabular arthroplasty (13.3%). RESULTS: At a mean 74.4 months follow-up, the overall revision rate was 15.0%. Primary malignancy (p < 0.001) and age < 50 years (p < 0.001) were risk factors for revision. The risks of death and implant failure were similar in patients with primary disease (p = 0.872), but the risk of death was significantly greater for patients who had metastatic bone disease (p < 0.001). Acetabular-related implant failures comprised 74.3% of revisions; however, no difference between hemiarthroplasty or arthroplasty groups (p = 0.209), or between monopolar or bipolar hemiarthroplasties (p = 0.307), was observed. There was greater radiological wear in patients with longer follow-up and primary bone malignancy. Re-revision rates following a revision PFEPR was 34.3%, with dual-mobility bearings having the lowest rate of instability and re-revision (15.4%). CONCLUSION: Hemiarthroplasty and arthroplasty PFEPRs carry the same risk of revision in the medium term, and is primarily due to acetabular complications. There is no difference in revision rates or erosion between monopolar and bipolar hemiarthroplasties. The main causes of failure were acetabular wear in the hemiarthroplasty group and instability in the arthroplasty group. These risks should be balanced and patient prognosis considered when contemplating the bearing choice. Dual-mobility, constrained bearings, or large diameter heads (> 32 mm) are recommended in all revision PFEPRs. Cite this article: Bone Joint J 2021;103-B(10):1633-1640.

Morbidity and mortality in patients undergoing lower limb arthroplasty surgery during the initial surge of the COVID-19 pandemic in the UK at a single-speciality orthopaedic hospital.

AIMS: The COVID-19 pandemic posed significant challenges to healthcare systems across the globe in 2020. There were concerns surrounding early reports of increased mortality among patients undergoing emergency or non-urgent surgery. We report the morbidity and mortality in patients who underwent arthroplasty procedures during the UK first stage of the pandemic. METHODS: Institutional review board approval was obtained for a review of prospectively collected data on consecutive patients who underwent arthroplasty procedures between March and May 2020 at a specialist orthopaedic centre in the UK. Data included diagnoses, comorbidities, BMI, American Society of Anesthesiologists grade, length of stay, and complications. The primary outcome was 30-day mortality and secondary outcomes were prevalence of SARS-CoV-2 infection, medical and surgical complications, and readmission within 30 days of discharge. The data collated were compared with series from the preceding three months. RESULTS: There were 167 elective procedures performed in the first three weeks of the study period, prior to the first national lockdown, and 57 emergency procedures thereafter. Three patients (1.3%) were readmitted within 30 days of discharge. There was one death (0.45%) due to SARS-CoV-2 infection after an emergency procedure. None of the patients developed complications of SARS-CoV-2 infection after elective arthroplasty. There was no observed spike in complications during in-hospital stay or in the early postoperative period. There was no statistically significant difference in survival between pre-COVID-19 and peri-COVID-19 groups (p = 0.624). We observed a higher number of emergency procedures performed during the pandemic within our institute. CONCLUSION: An international cohort has reported 30-day mortality as 28.8% following orthopaedic procedures during the pandemic. There are currently no reports on clinical outcomes of patients treated with lower limb reconstructive surgery during the same period. While an effective vaccine is developed and widely accepted, it is very likely that SARS-CoV2 infection remains endemic. We believe that this report will help guide future restoration planning here in the UK and abroad. Cite this article: Bone Jt Open 2021;2(5):323-329.

Chondrosarcoma 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.