Expandable distal femur megaprosthesis: A European Musculoskeletal Oncology Society study on 299 cases

Failure Modes in Orthopedic Oncologic Reconstructive Surgery: A Review of Imaging Findings and Failure Rates

Limb salvage surgeries utilizing endoprostheses and allografts are performed for a variety of oncologic conditions. These reconstructions can fail and require revision for many reasons, which are outlined and classified into mechanical failures (soft tissue failures, aseptic loosening, structural failure), non-mechanical failures (infection, tumor progression), and pediatric failures (physeal arrest, growth dysplasia). Distinct radiologic and clinical findings define specific failure subtypes but are sparsely illustrated in the radiology literature. Specifically, an understanding of the organizational structure of the failure modes can direct radiologists' search for post-reconstruction complications, enhance an appreciation of their prognostic significance, and facilitate research by standardizing the language and conceptual framework around outcomes. The purpose of this review is to highlight the key radiologic findings and imaging studies of each failure mode in orthopedic oncologic reconstructive surgery in the context of risk factors, failure rates, prognosis and survival statistics, and clinical decision-making regarding chemotherapy, radiation, and revision surgery.

Incidence and management of secondary deformities after megaendoprosthetic proximal femur replacement in skeletally immature bone sarcoma patients

INTRODUCTION

Megaendoprosthetic reconstruction of bone defects in skeletally immature patients has led to the development of unique complications and secondary deformities not observed in adult patient cohorts. With an increasing number of megaendoprosthetic replacements performed, orthopedic oncologists still gain experience in the incidence and type of secondary deformities caused. In this study, we report the incidence, probable cause and management outcome of two secondary deformities after megaendoprosthetic reconstruction of the proximal femur: hip dysplasia and genu valgum.

MATERIALS AND METHODS

Retrospective analysis of 14 patients who underwent primary and/or repeat reconstruction/surgery with a megaendoprosthetic proximal femur replacement between 2018 and 2022.

RESULTS

Mean patient age was 9.1 years (range 4-17 years). Stress shielding was observed in 71.4%. Hip dislocation was the most frequent complication (50%). While four dislocations occurred without an underlying deformity, secondary hip dysplasia was identified in 58.3% (n = 7/12) of intraarticular resections and reconstructions, leading to dislocation in 71.4% (n = 5/7). A genu valgum deformity was observed in 41.6% (n = 5/12). The incidence of secondary hip dysplasia and concomitant genu valgum was 42.9% (n = 3/7). Triple pelvic osteotomy led to rebound hip dysplasia in two cases (patients aged < 10 years), whereas acetabular socket replacement led to stable hip joints over the course of follow-up. Temporary hemiepiphyseodesis was applied to address secondary genu valgum.

CONCLUSIONS

Patients aged < 10 years were prone to develop secondary hip dysplasia and genu valgum following proximal femur replacement in this study. Management of secondary deformities should depend on remaining skeletal growth. Stress shielding was observed in almost all skeletally immature patients.

Expandable endoprostheses in skeletally immature patients: Where we are

Approximately 45 percent of malignant bone tumors are seen under the age of 16 and one of the important results of growth plate sacrification in patients with immature skeletons is limb inequality. Until the early 1990s, the treatment options for these patients were rotationplasty or amputation. Multimodal approaches that combine imaging, chemotherapy, and surgical techniques have enabled the development of limb-preserving methods with satisfactory results. In order to overcome inequality problems, expandable prostheses have been developed in the 1980s. Extendable endoprosthesis replacements have been improved over the years and are now an established and safe alternative. Noninvasive prostheses appear to be advantageous compared to minimally invasive expandable prostheses that require multiple surgical procedures, but the complication rate remains high. Therefore, although expandable prostheses are not the definitive answer to the treatment of bone sarcomas in skeletally immature children, they are still a suitable interim choice until full adulthood is achieved. Due to reported high complication rates, the procedures require significant experience and are recommended for use only in specialized cancer centers.

Survivorship, complications, and outcomes following distal femoral replacement for neoplastic indications

Background

Distal femoral replacements (DFRs) are excellent treatment options for limb salvage procedures in patients who have bone loss secondary to neoplasm. Multiple studies report adequate survivorship and complication rates following DFR implantation, primarily for non-neoplastic indications. However, current literature regarding neoplasm-specific reports is often limited by sample size, survivorship, and patient reported outcome measurements. Therefore, we sought to examine patients who received a DFR for a neoplastic indication at multiple tertiary academic centers. Specific outcomes analyzed included: (1) revision-free survival, (2) medical/surgical complications, and (3) Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR).

Methods

All patients who underwent a DFR for a neoplastic indication were retrospectively reviewed. A total of 29 knees were included for various neoplastic indications. Outcomes of interest included: post-operative thromboses, pneumonia, dislocations, periprosthetic joint infections (PJIs), aseptic loosening, osteolysis, emergency department visits, inpatient readmissions, and revision surgeries. Patient-reported outcome measure (PROM) collected included: Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR).

Results

Revision-free survivorship was 72.4 % at 23 months with radiographic follow-up. PJI was the most common post-operative complication, affecting 3 knees (10.3 %). The mean number of emergency department visits and inpatient readmissions averaged less than one per patient (0.63 and 0.41, respectively). KOOS JR scores improved markedly among from baseline to final follow-up (44.1-57.8).

Conclusion

The use of DFR led to satisfactory medium-term clinical outcomes with an acceptable complication rate for this challenging group of patients. The marked improvement in patient satisfaction for this patient population gives a promising outlook for patients who will undergo this procedure in the future and can guide patient-provider regarding surgical expectations.

Limb salvage surgery reconstructive techniques following long-bone lower limb oncological resection: a systematic review and meta-analysis

BACKGROUND

Limb salvage surgery (LSS) is now considered the gold standard surgical treatment for lower limb bone sarcomas. However, there is a paucity of literature comparing the various LSS reconstructive options. The aim of this systematic review and meta-analysis was to compare functional outcomes and complications of LSS reconstructive techniques.

METHODS

The primary aim of the meta-analysis was to determine functional outcomes from the pooled data utilizing the Musculoskeletal Tumour Society score (MSTS). Comparisons could then made for this outcome between biological and prosthetic, vascularised and non-vascularised, and prosthetic and composite reconstructions. The secondary aim was to compare complication outcomes of each reconstruction. Standardized mean difference (Cohen's d) and odds ratios were estimated using a random effects model.

RESULTS

Fourteen studies with a total of 785 patients were included. We found structural failure was 75% less likely to occur in prosthetic reconstruction compared to biological (OR = 0.24; 95% CI: 0.07-0.79; P = 0.02). We did not find any evidence of difference in function (MSTS score) between vascularised verses non-vascularised reconstructions (Cohen's d = -1.14; 95% CI = -3.06 to 0.78; I2  = 87%). Other analyses comparing complications found no difference between the reconstructive groups.

CONCLUSION

The study found no correlation between functional outcomes and the type of LSS reconstruction. Structural failure was more likely to occur in biological when compared with prosthetic reconstruction. There was no correlation between the incidence of other complications and the type of LSS technique. This suggests a role for improved approaches to reconstruction methods including bioprinting and bioresorbable devices.

Femoral Magnetic Lengthening After Distal Femur Endoprosthetic Reconstruction in a Pediatric Patient: A Case Report

CASE

A 10-year-old boy with osteosarcoma of the left distal femur underwent resection with compressive osseointegration endoprosthetic reconstruction, gradually resulting in a 4.5-cm leg-length difference with significant predicted progression. Two years after resection, he underwent right distal femur and proximal tibia epiphysiodesis and placement of a left femoral magnetic lengthening nail. At 2 years after lengthening and skeletal maturity, the patient has symmetric limb lengths, no pain, and returned to sports.

CONCLUSION

A magnetic lengthening nail with contralateral epiphysiodesis is a viable option for correcting limb-length discrepancy after distal femur endoprosthetic reconstruction in a pediatric patient.

[Primary malignant bone tumors]

Primary malignant bone tumors are rare. Due to an associated worsening of the prognosis by diagnostic delay, these tumors must not be overlooked in the routine clinical practice and should therefore always be included in the differential diagnosis for the clarification of musculoskeletal complaints. A correct interpretation of the diagnostic procedure, radiological investigations and a biopsy of doubtful lesions can confirm the diagnosis. Osteosarcoma, chondrosarcoma and Ewing's sarcoma are the three most frequent primary malignant bone tumors and other entities occur only sporadically. While the prognosis of osteosarcoma and Ewing's sarcoma has been vastly improved with chemotherapy, chondrosarcomas mostly respond only poorly or not at all to systemic chemotherapy. Wide resection represents the gold standard in the surgical management of all primary malignant bone tumors. In addition, Ewing's sarcoma responds well to irradiation. The multidisciplinary management of primary malignant bone tumors should be performed at dedicated and specialized centers.

Femoral Discrepancy After Childhood Bone Sarcoma Surgery Can Be Treated With Magnetic Intramedullary Nails

This study aims to determine whether femoral lengthening with a magnetic motorized intramedullary nail (PRECICE; NuVasive) is safe and effective in patients with discrepancy due to limb salvage performed for bone sarcomas before skeletal maturity. Six patients (male, 4; female, 2) with a mean age of 9.3 years (range, 4.8-12.8 years) at the time of index limb salvage surgery were retrospectively analyzed. Four patients had undergone biological reconstruction with liquid-nitrogen recycled frozen autograft shell and inlaid vascular fibula combination and 2 had undergone nonbiological reconstruction with distal femur modular tumor endoprosthesis. The mean age at PRECICE operation was 16.1 years (range, 13.4-20.1 years). The mean prelengthening femoral discrepancy was measured as 60 mm (range, 39-80 mm). Lengthening was achieved in 5 of these 6 patients. Although the PRECICE nail was successfully implanted in the sixth patient, lengthening could never be performed owing to failure to overcome the chronic diaphyseal nonunion first, as intended with compressive use of the nail. For the other 5 patients, in whom lengthening was performed, the mean lengthening was 45 mm (range, 35-52 mm), the mean ratio of achieved to planned lengthening was 93% (range, 74%-100%), and the mean bone-healing index was 41 days per cm (range, 24-69 days per cm). Mean Musculoskeletal Tumor Society score improved from 25.6 to 27.2 after lengthening. No major complications occurred. The outcomes of this study demonstrate that the PRECICE implant can safely and effectively correct femoral length discrepancy caused by limb salvage performed for osteosarcoma before skeletal maturity. [Orthopedics. 2023;46(1):27-34.].

A comparison of osteoarticular allografts and allograft-prosthesis composites for reconstruction of the distal femur after resection of a bone tumour in childhood : a retrospective study

AIMS

Osteoarticular reconstruction of the distal femur in childhood has the advantage of preserving the tibial physis. However, due to the small size of the distal femur, matching the host bone with an osteoarticular allograft is challenging. In this study, we compared the outcomes and complications of a resurfaced allograft-prosthesis composite (rAPC) with those of an osteoarticular allograft to reconstruct the distal femur in children.

METHODS

A retrospective analysis of 33 skeletally immature children with a malignant tumour of the distal femur, who underwent resection and reconstruction with a rAPC (n = 15) or osteoarticular allograft (n = 18), was conducted. The median age of the patients was ten years (interquartile range (IQR) 9 to 11) in the osteoarticular allograft group and nine years (IQR 8 to 10) in the rAPC group (p = 0.781). The median follow-up of the patients was seven years (IQR 4 to 8) in the osteoarticular allograft group and six years (IQR 3 to 7) in the rAPC group (p = 0.483). Limb function was evaluated using the Musculoskeletal Tumor Society (MSTS) score.

RESULTS

At final follow-up, the knee was unstable in 9/18 patients (50%) in the osteoarticular allograft group and 2/15 patients (13%) in the rAPC group (p = 0.026). The median range of motion (ROM) of the knee was 117° (IQR 115° to 120°) in the osteoarticular allograft group and 100° (IQR 95° to 105°) in the rAPC group (p < 0.001). The median MSTS score was 25 (IQR 23 to 26) in the osteoarticular allograft group and 28 (IQR 26 to 29) in the rAPC group (p = 0.007). Osteoarthritic change was detected in 11/18 patients (61%) in the osteoarticular allograft group and in 4/15 (26%) patients in the rAPC group (p = 0.048).

CONCLUSION

In our series, a resurfaced allograft-prosthesis composite provided better knee stability and function, with a lower rate of osteoarthritis; an osteoarticular allograft was associated with better knee ROM.Cite this article: Bone Joint J 2022;104-B(10):1174-1179.

Surgical Site Infection after Bone Tumor Surgery: Risk Factors and New Preventive Techniques

The management of malignant bone tumors requires multidisciplinary interventions including chemotherapy, radiation therapy, and surgical tumor resection and reconstruction. Surgical site infection (SSI) is a serious complication in the treatment of malignant bone tumors. Compared to other orthopedic surgeries, the surgical treatment of malignant bone tumors is associated with higher rates of SSIs. In patients with SSIs, additional surgeries, long-term administrations of antibiotics, extended hospital stays, and the postponement of scheduled adjuvant treatments are required. Therefore, SSI may adversely affect functional and oncological outcomes. To improve surgical outcomes in patients with malignant bone tumors, preoperative risk assessments for SSIs, new preventive techniques against SSIs, and the optimal use of prophylactic antibiotics are often required. Previous reports have demonstrated that age, tumor site (pelvis and tibia), extended operative time, implant use, body mass index, leukocytopenia, and reconstruction procedures are associated with an increased risk for SSIs. Furthermore, prophylactic techniques, such as silver and iodine coatings on implants, have been developed and proven to be efficacious and safe in clinical studies. In this review, predictive factors of SSIs and new prophylactic techniques are discussed.

Survival and failure modes of the Compress® spindle and expandable distal femur endoprosthesis among pediatric patients: A multi‐institutional study

BACKGROUND

Expandable endoprostheses can be used to equalize limb length for pediatric patients requiring reconstruction following large bony oncologic resections. Outcomes of the Compress® Compliant Pre-Stress (CPS) spindle paired with an Orthopedic Salvage System expandable distal femur endoprosthesis have not been reported.

METHODS

We conducted a multi-institutional retrospective study of pediatric patients with distal femoral bone sarcomas reconstructed with the above endoprostheses. Statistical analysis utilized Kaplan-Meier survival technique and competing risk analysis.

RESULTS

Thirty-six patients were included from five institutions. Spindle survivorship was 86.3% (95% confidence interval [CI], 67.7-93.5) at 10 years. Two patients had a failure of osseointegration (5.7%), both within 12 months. Twenty-two (59%) patients had 70 lengthening procedures, with mean expansions of 3.2 cm (range: 1-9) over 3.4 surgeries. The expandable mechanism failed in eight patients with a cumulative incidence of 16.1% (95% CI, 5.6-31.5) at 5 years. Twenty-nine patients sustained International Society of Limb Salvage failures requiring 63 unplanned surgeries. Periprosthetic joint infection occurred in six patients (16.7%). Limb preservation rate was 91% at 10 years.

CONCLUSIONS

There is a high rate of osseointegration of the Compress® spindle among pediatric patients when coupled with an expandable implant. However, there is a high rate of expansion mechanism failure and prosthetic joint infections requiring revision surgery.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Long-term follow-up of children treated with the Repiphysis expandable prosthesis for lower extremity bone sarcoma

Expandable endoprostheses provide a limb salvage option for skeletally immature patients with bone sarcoma of the lower extremities. Initial reports of the Repiphysis prosthesis were encouraging; however, medium-term follow-up revealed high complication rates. We report on the long-term follow-up of a cohort of patients treated with the Repiphysis prosthesis. Eleven patients were included in the study. Data collected included sex, age at surgery, duration of follow-up, site of disease, histologic diagnosis, number of lengthening sessions, amount lengthened, postoperative complications, endoprosthetic failure, mode of endoprosthetic failure, duration from index surgery to failure and to revision, type of revision surgery and final limb-length discrepancy. The average duration of follow-up from the time of surgery was 180 months (range, 144-215 months). Fifteen Repiphysis implants were used in 11 patients. All implants failed with an average time from surgery to failure of 36 months (range, 3-72 months). Twenty-four complications were observed: one wound dehiscence, two deep infections, 18 mechanical failures, implant collapse with destruction of proximal tibia epiphysis in two and one periprosthetic proximal femur fracture with dislodgement of the stem. Despite being an option for limb salvage, the Repiphysis prosthesis has a high rate of mechanical failure and need for revision, similar to other expandable implants. The authors, therefore, recommend full disclosure of the potential short- and long-term complications and need for revision, as well as alternative treatment options if their use is considered. Level of evidence: IV (Therapeutic).

Noninvasive Expandable Endoprostheses From Reconstruction to Skeletal Maturity: A Surgical Technique and Lengthening Guide

Limb salvage is the benchmark for pediatric extremity bone sarcomas. However, reconstructive strategies must account for any anticipated remaining growth potential and the resultant limb inequality. Expandable endoprostheses offer the theoretical advantage of immediate weight-bearing, predictable function, and reliable maintenance of leg-length equality. The evolution of the lengthening mechanism now permits noninvasive lengthening, opposed to the multiple open procedures of the past. These design improvements have contributed to their growing popularity. Experience has indicated that these noninvasive implants more reliably achieve leg-length equality, have longer failure-free survival, and decreased complications, although some have noted gearbox and lengthening failures. Currently, no standardize technique exists for managing patients with noninvasive expandable implants from the time of reconstruction to final lengthening at skeletal maturity. This blueprint aims to provide a detailed surgical technique, lengthening schedule, and recommendations for the mitigation and management of complications to achieve successful limb salvage with noninvasive expandable endoprostheses.

Intercalary reconstruction of the distal femur with or without physeal preservation: results and impact on limb growth

PURPOSE

Allograft reconstruction with or without vascularized fibula can be a valuable solution to treat childhood intercalary tumours of the distal femur. We aimed to assess the oncological status, complication rate and survival of distal femur intercalary reconstruction after trans-metaphyseal (TMR) and trans-epiphyseal resection (TER). We also evaluated the impact of distal temporary graft fixation on skeletal growth after TMR.

METHODS

We retrospectively reviewed 23 skeletally immature patients affected by distal femur osteosarcoma (18) and Ewing sarcoma (5). Mean patients age was 10.3 years. In 11 cases, TMR was performed with physis preservation and temporary distal graft fixation. In 9 patients, TER was performed with growth plate sacrifice. The last 3 cases were treated with TMR and sliding plate fixation.

RESULTS

Mean follow-up was 8.4 years. No deaths occurred, but 3 patients presented lung metastasis and 2 cases presented local recurrence in soft tissues. 10 implant-related complications occurred, all surgically treated. At skeletal maturity, mean femoral dysmetria was 2.3 cm after TMR and temporary epiphysiodesis, and 3.1 cm after TER. In TMR group, a strong trend towards physeal recovery was observed after epiphyseal screws removal (p = 0.061), but valgus deformity in distal femur was more frequent (p = 0.049). MSTS score was good or excellent in all patients, with no statistically significant difference between TMR and TER.

CONCLUSIONS

Intercalary graft reconstruction after TMR and TER allows good local disease control and excellent functional results with long-term follow-up. Temporary distal fixation might reduce the final limb discrepancy after TMR, but valgus deformity could develop.

LEVEL OF EVIDENCE

Level IV.

Lower limb reconstruction for malignant bone tumours in children

Malignant bone tumours of the lower limb represent the majority of cases in both osteosarcoma and Ewing sarcoma in the growth period. Surgical treatment represents a key element of treatment. Different localizations and age groups require a differentiated surgical approach. Life and limb salvage are first on the list of treatment goals, followed by functional and cosmetic considerations. This review article delivers and discusses current surgical treatment strategies and outcomes for lower limb malignant bone tumours in children.

Long-term outcomes and improved risk of revision following tumor endoprosthetic replacement of the distal femur: Single institutional results

Purpose

This study assessed revision characteristics following distal femur tumor endoprosthetic replacement.

Methods

Fifty-seven procedures were performed between 2005 and 2019. The cumulative incidence of implant revision was calculated with death as a competing risk.

Results

The all-cause revision rate was 21.1% (n = 12) at a mean 65.3 ± 47.3 months. Competing risk analysis revealed a cumulative revision incidence of 12.0% (95% CI, 3.6-25.9%) at five years and 36.5% (95% CI, 12.8-61.0%) at ten years.

Conclusions

We provide an accurate assessment of revision risk which is slightly lower than historical controls, with identification of failure modes to reliably inform patient expectations.

Level of evidence

III. Retrospective Study.