Distal femur resection with endoprosthetic reconstruction: a long-term followup study

Outcomes of distal femoral replacement versus internal fixation for metastatic bone diseases of the distal femur

Background

In clinical practice, internal fixation (IF) is a commonly utilized technique for metastatic bone disease (MBD) to the distal femur. Additionally, distal femoral reconstruction (DFR) has shown to be an effective surgical technique for primary tumors and MBD in the distal femur. The existing body of research comparing these methods has not focused on MBD or pathological fractures and thus does not guide surgical approach in the case of distal femoral MBD.

Methods

A multi-institutional retrospective review of musculoskeletal oncology patients treated surgically with IF (n = 29) or DFR (n = 34) for distal femoral MBD between 2005 and 2023. Overall survival, revision risk, and functional status were assessed.

Results

5-year patient overall survival was 47.9 % (CI, 29.5-77.6 %) and 46.6 % (CI, 31.5-68.8 %), for DFR and IF, respectively (p = 0.91). After competing risk analysis, the 5-year risk of implant revision for DFR was 18 % (95 % CI: 5.1-37 %) and 11 % for IF (95 % CI: 2.4-28 %) (p = 0.3). DFR had longer operative times (p = 0.002), higher blood loss (p < 0.001), and greater postoperative (p = 0.006) complications than IF. In addition, patients undergoing DFR had more distal lesions than patients who received IF (p = 0.003).

Conclusion

Despite similar overall survival and revision rates, IF may be preferable for patients due to its shorter operative time and lower rates of complication than DFR. However, specific anatomic location in the distal femur must be considered prior to deciding which procedure is optimal.

The survival and complication profiles of the Compress® Endoprosthesis: A systematic review and meta-analysis

Background/purpose

This study aimed to summarize the survival and complication profiles of the compress® endoprosthesis (CPS) through a systematic review and meta-analysis.

Methods

Online databases (PubMed, EMBASE and Web of Science) were searched from inception to November 2023. Trials were included that involved the use of CPS for endoprosthetic replacement in patients with massive segmental bone defects. Patients' clinical characteristics and demographic data were extracted using a standardized form. The methodological quality of included 13 non-comparative studies was assessed on basis of the Methodological Index for Non-Randomized Studies (MINORS). All the available Kaplan-Meier curves in the included studies were digitized and combined using Engauge-Digitizer software and the R Project for Statistical Computing.

Results

The meta-analysis of thirteen included studies indicated: the all-cause failure rates of CPS were 26.3 % after surgery, in which the occurrence rates of aseptic loosening were 5.8 %. And the incidences of other complications were as follows: soft tissue failure (1.8 %), structure failure (8.2 %), infection (9.5 %), tumor progression (1.1 %). The 1-, 4-, and 8-year overall survival rates for all-cause failure with 95 % CI were 89 % (86 %-92 %), 75 % (71 %-79 %) and 65 % (60 %-70 %), respectively. The estimated mean survival time of all-cause failure was 145 months (95 % CI, 127-148 months), and the estimated median survival time of all-cause failure was 187 months (95 % CI, 135-198 months). The 1-, 4-, and 8-year overall survival rates of aseptic loosening with 95 % CI were 96 % (94 %-98 %), 91 % (87 %-95 %) and 88 % (83 %-93 %), respectively. The estimated mean survival time of aseptic loosening was 148 months (95 % CI, 137-153 months).

Conclusion

CPS's innovative spring system promotes bone ingrowth by providing immediate and high-compression fixation, thereby reducing the risk of aseptic loosening caused by stress shielding and particle-induced osteolysis. CPS requires less residual bone mass for reconstructing massive segmental bone defects and facilitates easier revision due to its non-cemented fixation. In addition, the survival rate, estimated mean survival time, and complication rates of CPS are not inferior to those of common endoprosthesis.

Patients Regularly Return to Medium- and Low-Impact Types of Sporting Activities Following Distal Femoral or Proximal Tibial Replacement After Resection of a Primary Bone Sarcoma

BACKGROUND

Little is known about the resumption of sporting activities following megaprosthetic reconstruction of the distal femur and proximal tibia after resection of a bone sarcoma. Thus, the aims of our study were: (1) to assess the functional outcome; (2) to evaluate pre- and post-operatively performed sporting activities; and (3) to identify potential beneficial and limiting factors.

METHODS

Between 1993 and 2015, a total of 230 patients underwent distal femoral replacement (DFR), and 96 patients underwent proximal tibial replacement (PTR). The exclusion criteria were death, amputation, living overseas, and a congenital disability. Functional outcome and sporting activities were assessed using the Musculoskeletal Tumor Society Score (MSTS), Toronto Extremity Salvage Score (TESS), Forgotten Joint Score (FJS), subjective knee value (SKV), the Tegner activity score (TS), and the modified weighted activity score (WAS).

RESULTS

There were 93 patients who had a median follow-up of 182 months (interquartile range (IQR) 130 to 260) after DFR with the following median scores: MSTS 18 (IQR 12 to 23), TESS 75% (IQR 60 to 84), FJS 25 (IQR 8 to 40), SKV 53% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 0 to 8). There were 42 patients who had a median follow-up of 193 months (IQR 137 to 244) after PTR had the following median scores: MSTS 17 (IQR 15 to 22), TESS 78% (IQR 68 to 88), FJS 32 (IQR 20 to 46), SKV 60% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 1 to 10). Postoperatively, 61% of DFR and 76% of PTR patients participated in at least one sporting activity.

CONCLUSIONS

The functional outcome is overall good with a regular resumption of sporting activities. Patients' age at surgery and higher preoperative sporting levels were associated with better functional outcomes and higher postoperative sporting activity.

Distal femoral megaprosthesis fracture treated by RescueSleeve MEGASYSTEM-C

Escalating revision surgery after megaprosthesis knee replacement sometimes raises the question of "limb salvage". Here we present a salvage technique for megaprosthesis fracture at the junction between the stem and the metaphyseal component. In this young active patient, the short residual proximal femur was not loose and was difficult to extract without prosthetic escalation. The technique described here conserved the well-fixed primary stem and used a custom-made RescueSleeve MEGASYSTEM-C connection sleeve (Link, Hamburg, Germany) plus spacer and a standard epiphyseal implant. This semi-conservative procedure avoided femorotomy or larger morbid segmental femoral resection. It conserved maximal bone stock and achieved rapid functional recovery. To our knowledge, this is the first reported case of this technique using a custom-made connecting part to manage megaprosthesis fracture. LEVEL OF EVIDENCE: IV.

Ortho-oncoplastic surgery in foot and ankle: A narrative overview on reconstruction of soft-tissue defects after oncologic resections

INTRODUCTION

Malignant tumors of the foot are rare, and treatment strategies are challenging considering the complex anatomy of this area. In recent years, dramatic advances in technology and collaborations between different specialties (such as orthopedic, oncology, radiology, plastic, and vascular surgery) significantly changed the approach to complex malignant tumors without resorting to limb removal. The combination of the strengths of both orthopedic surgery and plastic surgery constitutes the modern definition of "orthoplasty." The aim of this review article is to provide treatment strategies that are available for reconstruction of foot and ankle in limb-salvage surgery after tumor resection, with a specific focus on microsurgical techniques in plastic surgery.

METHODS

We conducted a comprehensive search for relevant papers across PubMed, Scopus, Embase, and Web of Science. We included patient-based studies reporting on procedures for soft-tissue reconstruction with small and large soft tissue defects. Indications, pros and cons, and technique tips are discussed for each type of reconstructive technique.

RESULTS

The search was done using literature of the past 30 years (from 1990 to date), resulting in about 725 articles describing over 2000 cases. Cutaneous flaps included lateral supramalleolar flap, medial plantar flap, reverse sural neurocutaneous island flap, medial leg flap, and lateral leg flap. Free flaps included anterolateral thigh flap, radial forearm flap, latissimus dorsi flap, gracilis muscle flap, lateral arm flap, and rectus abdominis flap.

CONCLUSIONS

The orthoplastic approach in musculoskeletal oncology is a collaborative model of orthopedic and plastic surgeons working together, resulting in a higher rate of successful limb salvage in patients at risk for amputation. Protocols, biologic substitutes, and surgical techniques are largely improved in the last decades increasing the possibility of functional reconstruction. Microsurgical strategies represent the new frontiers in these demanding reconstructions.

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.

Systemic Cisplatin Does Not Affect the Bone Regeneration Process in a Critical Size Defect Murine Model

Osteosarcoma (OS) is the most common primary malignant bone tumor, and the current standard of care for OS includes neoadjuvant chemotherapy, followed by an R0 surgical resection of the primary tumor, and then postsurgical adjuvant chemotherapy. Bone reconstruction following OS resection is particularly challenging due to the size of the bone voids and because patients are treated with adjuvant and neoadjuvant systemic chemotherapy, which theoretically could impact bone formation. We hypothesized that an osteogenic material could be used in order to induce bone regeneration when adjuvant or neoadjuvant chemotherapy is given. We utilized a biomimetic, biodegradable magnesium-doped hydroxyapatite/type I collagen composite material (MHA/Coll) to promote bone regeneration in the presence of systemic chemotherapy in a murine critical size defect model. We found that in the presence of neoadjuvant or adjuvant chemotherapy, MHA/Coll is able to enhance and increase bone formation in a murine critical size defect model (11.16 ± 2.55 or 13.80 ± 3.18 versus 8.70 ± 0.81 mm3) for pre-op cisplatin + MHA/Coll (p-value = 0.1639) and MHA/Coll + post-op cisplatin (p-value = 0.1538), respectively, at 12 weeks. These findings indicate that neoadjuvant and adjuvant chemotherapy will not affect the ability of a biomimetic scaffold to regenerate bone to repair bone voids in OS patients. This preliminary data demonstrates that bone regeneration can occur in the presence of chemotherapy, suggesting that there may not be a necessity to modify the current standard of care concerning neoadjuvant and adjuvant chemotherapy for the treatment of metastatic sites or micrometastases.

Proximal Femur Salvage in Revision Knee Arthroplasty Due to Oncologic Indications: Long-term Results of Onlay and Overlapping Allograft in Revision Surgeries

Background

Mechanical failures of tumor endoprosthesis in the distal femur usually require revision surgery. We investigated if the proximal femur host bone can be salvaged by onlay and overlapping allograft in revision surgeries due to aseptic loosening and stem fractures.

Methods

We retrospectively reviewed 18 patients (7 men and 11 women) with osteosarcoma around the knee. The entire cohort was classified into three subgroups (no bone graft: 6, onlay allograft: 7, and overlapping allograft: 5) according to our treatment strategy.

Results

The median interval from the initial surgery to the revision was 94.5 months (range, 21-219 months), and the median follow-up period from the revision surgery was 88.0 months (range, 24-179 months). At the last follow-up, 9 of the 18 patients maintained their endoprostheses, and the 5-year prosthesis survival rate was 57.9%. Limb survival was 100%. Five-year prosthesis survival rate was 66.7% in the no bone graft group, 85.7% in the onlay allograft group while 30.0% in the overlapping allograft group. In the no bone graft group and onlay allograft group, 66.7% (4/6) and 57.1% (4/7) maintained their revision prostheses while no prostheses survived in the overlapping allograft group. Recurrent stem loosening was observed in 14.2% (1/7) and 60.0% (3/5) of the onlay allograft and overlapping allograft groups, respectively, despite allograft bone union. The complication rate was 66.7% (12/18) in the entire cohort. The most common type of complication was infection (n = 6), followed by aseptic loosening (n = 4) and mechanical failure (n = 2).

Conclusions

This study indicates that onlay allograft can be used as a supportive method in revising failed endoprosthesis if the extent of host bone destruction is extensive. However, applying overlapping allograft to secure bone stock showed a high rate of mechanical failures and infection in the long term. Future studies with a larger cohort are necessary to assess the prognostic factors for the higher complication rate in overlapping allograft and the need for overlapping allograft. Surveillance with consideration of the risk of anteromedial osteolysis in allograft and efforts for prevention of periprosthetic infection are essential.

Endoprosthetic reconstruction for lower extremity soft tissue sarcomas with bone involvement

BACKGROUND AND OBJECTIVES

Bone resection and endoprosthetic reconstruction (EPR) in the setting of soft tissue sarcoma (STS) management is rare and incurs unique challenges. We aim to report on the surgical and oncological outcomes of this relatively previously undocumented cohort.

METHODS

This is a single-center retrospective review of prospectively collected data for patients who required EPRs following resection of STSs of the lower extremity. Following inclusion criteria, we assessed 29 cases of EPR for primary STS of the lower limb.

RESULTS

The mean age was 54 years (range 18-84). Of the 29 patients, there were 6 total femur, 11 proximal femur, 4 intercalary, and 8 distal femur EPRs. Fourteen of 29 patients (48%) underwent re-operations for surgical complications, with 9 relating to infection (31%). When a matched cohort analysis was performed comparing our cohort to STSs that did not necessitate EPR, a reduced rate of overall survival and metastasis-free survival was found in those requiring EPR.

CONCLUSION

This series identifies a high rate of complication from EPRs performed for STS. Patients should be cautioned about the high rate of infection, surgical complications, and lower overall survival in this setting.

Calcium Phosphate Cements as Carriers of Functional Substances for the Treatment of Bone Tissue

Interest in calcium phosphate cements as materials for the restoration and treatment of bone tissue defects is still high. Despite commercialization and use in the clinic, the calcium phosphate cements have great potential for development. Existing approaches to the production of calcium phosphate cements as drugs are analyzed. A description of the pathogenesis of the main diseases of bone tissue (trauma, osteomyelitis, osteoporosis and tumor) and effective common treatment strategies are presented in the review. An analysis of the modern understanding of the complex action of the cement matrix and the additives and drugs distributed in it in relation to the successful treatment of bone defects is given. The mechanisms of biological action of functional substances determine the effectiveness of use in certain clinical cases. An important direction of using calcium phosphate cements as a carrier of functional substances is the volumetric incorporation of anti-inflammatory, antitumor, antiresorptive and osteogenic functional substances. The main functionalization requirement for carrier materials is prolonged elution. Various release factors related to the matrix, functional substances and elution conditions are considered in the work. It is shown that cements are a complex system. Changing one of the many initial parameters in a wide range changes the final characteristics of the matrix and, accordingly, the kinetics. The main approaches to the effective functionalization of calcium phosphate cements are considered in the review.

The history of resection prosthesis

INTRODUCTION

The purpose of this historical review is to highlight the progression and development of prosthetic reconstruction with a focus on the modular distal femur with hinged total knee arthroplasty.

METHOD

Scientific literature was searched for descriptions of endoprosthetic reconstruction of the extremities to provide a thorough overview of the subject, focusing the research on the evolution of limb salvage of the distal femur.

RESULTS

After the first works of Gluck and Giordano, with ivory and metal and the pioneer shoulder prosthesis by Pean in the late 1890s, a great advancement was brought by reconstructions performed for injured soldiers of the Great War. By the 1940s, replacement of all the main joints had been attempted, and documented.

DISCUSSION

Walldius in the 1950s developed a fully constrained hinge knee, offering for the first time a consistent and replicable method of substituting the joint. In 1953, Shiers' prosthesis allowed for good flexion and extension. Stanmore and GUEPAR group prosthesis in the 1960s were the first to have a different right and left side model. The rotating hinge was developed in 1978 by Walker, with the innovative concept of six degrees of freedom. Between 1979 and 1982, Kotz developed the modular segmental replacement that, added to a fixed hinge knee, permitted the revolutionary creation of the modern distal femur replacement.

CONCLUSION

The study of the materials and mechanical solutions that was brought to the modern distal femur resection prosthesis is a good example of a virtuous multidisciplinary teamwork between orthopaedic surgeons, anatomists, and biomechanical engineers.

Infections of Tumor Prostheses: An Updated Review on Risk Factors, Microbiology, Diagnosis, and Treatment Strategies

Several causes contribute to the high infection rate in tumor prostheses, including extensive tissue dissection and patients' immunosuppression due to the neoplastic disease. Most of these infections develop within the first 2 years following surgery with 70% of them occurring during the first year, while they are often associated with a low pathogen burden. The pathogenesis of infections in tumor prostheses is linked to bacteria developing in biofilms. Approximately half of them are caused by Staphylococcus spp., followed by Streptococcus spp., Enterococcus spp., and Enterobacteriaceae spp., while multiple pathogens may be isolated in up to 25% of the cases, with coagulase-negative Staphylococci (CoNS) and Enterococccus spp. being the most frequent pair. Although early detection and timely management are essential for complete resolution of these challenging infections, prompt diagnosis is problematic due to the highly varying clinical symptoms and the lack of specific preoperative and intraoperative diagnostic tests. Surgical management with one- or two-stage revision surgery is the mainstay for successful eradication of these infections. The recent advances in laboratory diagnostics and the development of biofilm-resistant prostheses over the past years have been areas of great interest, as research is now focused on prevention strategies. The aim of this study is to review and consolidate the current knowledge regarding the epidemiology, risk factors, microbiology, and diagnosis of infections of tumor prostheses, and to review the current concepts for their treatment and outcomes.

Postoperative Functional Assessment in Patients with Tumors Around the Knee Treated with Endoprosthetic Reconstruction: A Multicenter Retrospective Cohort Study

OBJECTIVES

The restoration of as much normal function as possible has become an important goal following the endoprosthetic reconstruction. The objective of this study was to assess the functional outcome after endoprosthetic reconstruction for tumors around the knee and to explore prognostic factors of functional outcome.

METHODS

We retrospectively collected data on patients who underwent tumor prosthetic replacements consecutively. Musculoskeletal Tumour Society score and Toronto Extremity Salvage Score were used to assess the functional outcome at 1, 3, 6, 12, and 24 months after surgery. The logistic model was used to select factors that had potential predictive value for postoperative function. Potential prognostic factors included age, gender, tumor site, type of tumor, length of bone resection, type of prosthesis, length of prosthetic stem, chemotherapy, pathological fracture, and body mass index.

RESULTS

At the 24 months after surgery, the mean musculoskeletal tumor society (MSTS) score was 81.4% and the mean Toronto extremity salvage score (TESS) was 83.6%. At the last follow-up, 68% of patients and 73% of patients received perfect or good MSTS score and TESS score, respectively. The multivariate analysis according to ordered-logit model showed that age < 35 years, distal femoral prosthesis, and length of bone resection < 14 cm were independent prognostic factors of better functional outcome.

CONCLUSIONS

Endoprosthetic reconstruction may provide good functional results for most patients. Younger patients with distal femoral prosthesis and shorter resection of bone (on the premise of complete resection of tumor) are more likely to obtain satisfactory functional results after surgery.

Classification and reconstruction of femoral bone defect in the revision of aseptic loosening of distal femoral endoprostheses: a 10-year multicenter retrospective analysis

Objective

This study proposes a system for classifying the aseptic loosening of distal femoral endoprostheses and discusses reconstruction methods for revision surgery, based on different classification types.

Methods

We retrospectively analyzed the data of patients who received revision surgery for aseptic loosening in distal femoral tumor endoprosthesis from January 2008 to December 2020 at 3 bone tumor treatment centers in China. Based on the patient imaging data, we proposed a classification system for the aseptic loosening of distal femoral endoprostheses and discussed its revision surgery strategy for various bone defects.

Results

A total of 31 patients were included in this study, including 21 males and 10 females aged 15–75 y (average: 44.3 y). First-revision surgery was performed on 24 patients, whereas second-revision surgery was conducted on 7 patients. The 31 patients were classified into different types based on the degree of aseptic loosening: Type I, 12 patients (38.7%); Type IIa, 7 patients (22.5%); Type IIb, 7 patients (22.5%); Type III, 4 patient (12.9%); and Type IV, 1 patient (3.2%). For type I, 11 patients underwent revisions with standard longer-stem prostheses (one with the original prosthesis), and one patient had the original prosthesis plus cortical allograft strut. For type II (a and b), 10 patients underwent revisions with original prosthesis or longer-stem prosthesis and 4 patients combined with cortical allograft strut. For type III, one patient underwent revision with a longer-stem prosthesis and the other 3 patients with a custom short-stem prosthesis. For type IV, only one patient underwent revision with a custom short-stem prosthesis.

Conclusions

Aseptic loosening of the distal femoral prosthesis can be divided into 4 types: type I, type II (a, b), type III and type IV. The reconstruction methods of our centers for different types of bone defects can offer some reference value in the revision of aseptic loosening.

Management of Primary Aggressive Tumors of the Knee

Primary bone sarcomas and aggressive benign bone tumors are relatively rare. It is essential to recognize features that are concerning for these aggressive tumors based on a patient's history, physical exam, and radiographs. Physicians and other health care providers should have a high suspicion for these tumors and promptly refer these patients to orthopaedic oncologists. A multidisciplinary, team-based approach is required to obtain an accurate diagnosis and provide comprehensive care. This review discussed the appropriate work-up, biopsy principles, relevant peri-operative medical management, and surgical treatment options for patients with aggressive primary bone tumors around the knee. Primary bone sarcomas (osteosarcoma and chondrosarcoma) and aggressive benign bone tumors (giant cell tumor, chondroblastoma, and chondromyxoid fibroma) that have a predilection to the distal femur and proximal tibia are the focus of this review.

Management of Pathologic Fractures around the Knee: Part 1-Distal Femur

Pathologic fractures secondary to metastatic disease are an increasingly prevalent problem. Such patients require multidisciplinary collaboration to optimize clinical outcomes. An established algorithm for clinical, laboratory, and radiographic work-up will ensure that each patient achieves the best outcome while avoiding catastrophic complications. Metastatic disease to the region of the knee is less commonly encountered than in other regions of the body, but it presents unique difficulties that merit discussion. Part one of this two-part article series will discuss the appropriate work-up of patients with suspected or impending pathologic fracture of the distal femur, highlight biopsy principles, address perioperative nonsurgical treatments that will optimize patient outcomes, and discuss available surgical treatment modalities.

The functional outcome after tumor resection and endoprosthesis around the knee: a systematic review

The evidence for the functional outcome of endo- prosthetic replacement (EPR) after tumour resection has been from few cohort studies. A scoping search revealed no systematic review on patient reported outcome measures after EPR around the knee. The purpose of this study was to evaluate the functional outcome of distal femoral and proximal tibial EPR after tumour resection. A systematic review was conducted using the PRISMA guidelines. The search identified 2560 articles from MEDLINE, EMBASE, CINAHL, and Web of Science. 36 studies satisfying the selection criteria were included for data synthesis. Pooled analysis was performed for homogenous studies. Narrative synthesis was performed for all the studies due to heterogeneity in methodological and statistical analysis. Amongst the overall patient population of 2930, mean ages ranged from 18-66 years and the mean follow up periods in the studies ranged from 12 - 180 months. The weighted mean functional outcome was similar for patients who had DFEPR and PTEPR. The functional outcome scores of Rotating Hinge Knee implants (RHK) were significantly greater than that for Fixed Hinge Knee implants (FHK). The weighted mean functional outcome scores were higher after cemented fixation and after primary EPR procedures. The current evidence suggests that functional out- come after EPR in the knee is good, and RHK implants are better than FHK implants. Functional outcome after primary EPR was significantly better than following revision EPR, and this underscores the importance of minimising complications at the primary surgery.

Prediction of soft tissue coverage following distal femur bone sarcoma resection: A preliminary report

We aimed to examine the predictability of the need for soft tissue reconstruction during limb-sparing surgery through preoperative magnetic resonance (MR) imaging in patients diagnosed with a malignant bone tumor in the distal femur. The study included 42 patients who were operated for a bone sarcoma of the distal femur at our clinic between 2016 and 2018. The recorded parameters included the demographic characteristics of the patients, tumor diagnosis, tumor side, total tumor volume, tumor soft tissue component volume, tumor soft tissue component volume-to-total tumor volume ratio, tumor localization by MR imaging, the need for soft tissue reconstruction, the muscles used for soft tissue reconstruction, the biopsy site, and the biopsy type. Tumor volume was calculated on MR imaging of the distal femur region performed before surgery. Our study established cut-off values for soft tissue reconstruction need following resection as a total tumor volume of 96.4 cm³ , a tumor soft tissue component volume of 22 cm³ , a tumor soft tissue component volume-to-total tumor volume ratio of 48.9%, and tumor localization in two different regions on axial distal femoral MR images. Considering these cut-off values, by calculating tumor volume values preoperatively we can predict the need for rotational muscle flaps for soft tissue coverage following distal femur bone sarcoma resection and endoprosthesis reconstruction. Anticipating the need for soft tissue reconstruction may affect the duration and success of the operation.

Osteogenesis in the presence of chemotherapy: A biomimetic approach

Osteosarcoma (OS) is the most common bone tumor in pediatrics. After resection, allografts or metal endoprostheses reconstruct bone voids, and systemic chemotherapy is used to prevent recurrence. This urges the development of novel treatment options for the regeneration of bone after excision. We utilized a previously developed biomimetic, biodegradable magnesium-doped hydroxyapatite/type I collagen composite material (MHA/Coll) to promote bone regeneration in the presence of chemotherapy. We also performed experiments to determine if human mesenchymal stem cells (hMSCs) seeded on MHA/Coll scaffold migrate less toward OS cells, suggesting that hMSCs will not contribute to tumor growth and therefore the potential of oncologic safety in vitro. Also, hMSCs seeded on MHA/Coll had increased expression of osteogenic genes (BGLAP, SPP1, ALP) compared to hMSCs in the 2D condition, even when exposed to chemotherapeutics. This is the first study to demonstrate that a highly osteogenic scaffold can potentially be oncologically safe because hMSCs on MHA/Coll tend to differentiate and lose the ability to migrate toward tumor cells. Therefore, hMSCs on MHA/Coll could potentially be utilized for bone regeneration after OS excision.

The risk factors for mechanical complication in endoprosthetic reconstruction of knee osteosarcoma

BACKGROUND

The increased limb survival rates and higher functional demands have also increased the mechanical complication rates of megaprostheses. This study aimed to analyse possible risk factors which can predispose patients to mechanical complications.

METHODS

Patients with knee osteosarcoma referred to our clinic from 1992 to 2014 were investigated retrospectively. The patients who underwent surgical resection and endoprosthetic reconstruction with at least 5 years of follow up were analysed. The revision of the megaprosthesis due to a mechanical complication was accepted as an endpoint. The possible risk factors, including cement usage, implant material, joint mechanism, neoadjuvant radiotherapy, and anatomical localization of the lesion, were analysed for any association with mechanical complication rates.

RESULTS

A total of 118 patients were included for final analysis. The average age was 24.5 years (standard deviation ±10.1, range: 15-64). Mechanical complication rate was 22% which included 19 aseptic loosenings and seven implant failures. The average time to mechanical complication was 32.5 months. Overall, 5-year implant survival was 78%. Multiple regression analysis revealed that cement usage is an independent risk factor for mechanical complication (P = 0.007). Although the 5-year implant survival was higher in rotating hinge and titanium implants compared with fixed hinge and cobalt chrome, the multiple regression model did not yield a correlation with mechanical complication rates.

CONCLUSION

Cemented implants showed significantly higher mechanical complication rates compared with cementless ones in this series of knee osteosarcoma patients who underwent megaprosthetic reconstruction. Hinge mechanism and implant material did not have a significant effect on mechanical complication rates.

The ACS-NSQIP surgical risk calculator is a poor predictor of postoperative complications in patients undergoing oncologic distal femoral replacement

BACKGROUND

Distal femur replacement (DFR) has become a preferred reconstruction for tumors involving the femur but is associated with known complications. The ACS-NSQIP surgical risk calculator is an online tool developed to estimate postoperative complications in the first 30-days, however, has not been used in patients undergoing DFR. The purpose of this study was determining the utility of the ACS-NSQIP calculator to predict postoperative complications.

METHODS

56 (30 male, 26 female) patients who underwent DFR were analyzed using the CPT codes: 27,365 (Under Excision Procedures on the Femur and Knee Joint), 27,447 (Arthroplasty, knee, condyle and plateau), 27,486 (Revision of total knee arthroplasty, with or without allograft), 27,487 (Revision of total knee arthroplasty, with or without allograft) and 27,488 (Repair, Revision, and/or Reconstruction Procedures on the Femur [Thigh Region] and Knee Joint). The predicted rates of complications were compared to the observed rates.

RESULTS

Complications were noted in 30 (54%) of patients. The predicted risk of complications based off the CPT codes were: 27,356 (14%); 27,447 (5%); 27,486 (7%); 27,487 (8%) and 27,488 (12%). Based on ROC curves, the use of the ACS-NSQIP score were poor predictors of complications (27356, AUC 0.54); (27447, AUC 0.45); (27486, AUC 0.45); (27487, AUC 0.46); (27488, AUC 0.46).

CONCLUSIONS

Distal femur arthroplasty performed in the setting of oncologic orthopedics is a complex procedure in a "high risk" surgical group. The ACS-NSQIP does not adequately predict the incidence of complications in these patients and cannot be reliably used in the shared decision-making process.

A long-term experience with Mutars tumor megaprostheses: analysis of 187 cases

PURPOSE

Modular megaprostheses have widely replaced allografts, as a reconstructive option; however, failures of these devices remain high. Aim of this study was to analyze outcomes, survival of the implants, incidence and types of complications with Mutars modular endoprostheses at long term.

METHODS

Between 2000 and 2019, 187 Mutars prostheses were implanted in two dedicated centers: 72 upper limbs and 115 lower limbs reconstructions. Diagnoses included 107 primary malignant bone or soft tissue tumors, 65 metastases, 8 benign bone tumors and 7 non-oncologic cases. Silver-coated prostheses were used in 118/187 (63%) cases.

RESULTS

At last follow-up, 76.5% of patients had retained their implant. The overall failure rate was 23.5% at a mean of 1.7 years. There were 22 mechanical failures and 22 non-mechanical failures. The overall implant survival to all types of failure was 68% and 52% at 5 and 10 years, respectively. Infection was the most common mode of failure with an incidence of 6.9%. Implant survival to infection was better for silver-coated implants than for standard implants even if with no significant difference (p = 0.56). Functional results were satisfactory in 97% of patients.

CONCLUSIONS

The overall implant survival at long term was satisfactory with Mutars prostheses. The incidence of complications with Mutars prosthesis is in line with the incidence reported in the literature with other types of tumor prosthesis. The most frequent cause of failure was infection with a lower incidence in silver-coated prostheses; silver coating seems to prevent infection in distal femur and proximal tibia. The silver coating seems to be particularly useful in two-stage revisions with a lower incidence of secondary amputation. In higher risk patients, silver-coated prostheses are the preferable choice for the reduction of the reinfection rate. The functional results of Mutars prostheses were excellent or good in most of cases. The current paper is design to enhance the literature on megaprosthesis in tumor surgery, proven that this system is one of the most used all over the word and one of the best performing.

Long-term competing risks for overall and cause-specific failure of rotating-hinge distal femoral arthroplasty for tumour reconstruction

AIMS

Rotating-hinge knee prostheses are commonly used to reconstruct the distal femur after resection of a tumour, despite the projected long-term burden of reoperation due to complications. Few studies have examined the factors that influence their failure and none, to our knowledge, have used competing risk models to do so. The purpose of this study was to determine the risk factors for failure of a rotating-hinge knee distal femoral arthroplasty using the Fine-Gray competing risk model.

METHODS

We retrospectively reviewed 209 consecutive patients who, between 1991 and 2016, had undergone resection of the distal femur for tumour and reconstruction using a rotating-hinge knee prosthesis. The study endpoint was failure of the prosthesis, defined as removal of the femoral component, the tibial component, or the bone-implant fixation; major revision (exchange of the femoral component, tibial component, or the bone-implant fixation); or amputation.

RESULTS

Multivariate Fine-Gray regression analyses revealed different hazards for each Henderson failure mode: percentage of femoral resection (p = 0.001) and extent of quadriceps muscle resection (p = 0.005) for overall prosthetic failure; extent of quadriceps muscle resection (p = 0.002) and fixation of femoral component (p = 0.011) for type 2 failure (aseptic loosening); age (p = 0.009) and percentage of femoral resection (p = 0.019) for type 3 failure (mechanical failure); and type of joint resection (p = 0.037) for type 4 (infection) were independent predictors. A bone stem ratio of > 2.5 reliably predicted aseptic loosening.

CONCLUSION

We identified independent risk factors for overall and cause-specific prosthetic failure after rotating-hinge knee distal femoral arthroplasty using a competing risk Fine-Gray model. A bone stem ratio > 2.5 reliably predicts aseptic loosening. An accurate knowledge of the risks of distal femoral arthroplasty after resection for tumour assists surgical planning and managing patient expectations. Cite this article: Bone Joint J 2021;103-B(8):1405-1413.

Resection arthrodesis and osteoarticular allografts reconstruction after resection of primary bone tumors around the knee: Long-term clinical outcomes and prognostic factors for failure of biological reconstruction

AIM

The biological reconstruction of the knee with osteoarticular allografts and resection arthrodesis have been reported but there has not yet been a direct comparison between both these procedures. This study aimed to identify the prognostic factors that influence failure of biological reconstruction and compared the results between both procedures.

METHODS

Between 1994 and 2017, we performed 92 limb-sparing procedures using resection arthrodesis (n = 53) and osteoarticular allograft reconstruction (n = 39) for the management of primary bone tumors around the knee. The minimum follow-up time was 2 years in both groups.

RESULTS

The failure rate of reconstruction in the osteoarticular allograft and resection arthrodesis group was 48.7% and 39.6%, respectively (p = 0.75). The mean MSTS score in the osteoarticular allograft and resection arthrodesis group was 23.7 and 21.8, respectively (p = 0.01). The significant risk factor for failure after biological reconstruction was the administration of chemotherapy (p = 0.001; HR = 3.39; 95% CI, 1.60-7.17).

CONCLUSION

Patients who underwent osteoarticular allograft had a better functional outcome than those who underwent resection arthrodesis reconstruction, but clinical outcomes between the groups were comparable. Chemotherapy is a significant adverse prognostic factor for failure of biological reconstruction.

Management of Large Segmental Bone Defects at the Knee With Intramedullary Stabilized Antibiotic Spacers During Two-Stage Treatment of Endoprosthetic Joint Infection

BACKGROUND

Following debridement of infected prostheses that require reconstruction with an endoprosthetic replacement (EPR), instability related to segmental residual bone defects present a challenge in management with 2-stage reimplantation.

METHODS

We retrospectively reviewed all patients treated for revision total joint or endoprosthetic infection at the knee from 1998 to 2018. At our institution, patients with skeletal defects >6 cm following explant of prosthesis and debridement (stage 1) were managed with intramedullary nail-stabilized antibiotic spacers. Following stage 1, antimicrobial therapy included 6 weeks of intravenous antibiotics and a minimum of 6 weeks of oral antibiotics. Following resolution of inflammatory markers and negative tissue cultures, reimplantation (stage 2) of an EPR was performed.

RESULTS

Twenty-one patients at a mean age of 54 ± 21 years were treated for prosthetic joint infection at the knee. Polymicrobial growth was detected in 38% of cases, followed by coagulase-negative staphylococci (24%) and Staphylococcus aureus (19%). Mean residual skeletal defect after stage 1 treatment was 20 cm. Prosthetic joint infection eradication was achieved in 18 (86%) patients, with a mean Musculoskeletal Tumor Society score of 77% and mean knee range of motion of 100°. Patients with polymicrobial infections had a greater number of surgeries prior to infection (P = .024), and were more likely to require additional debridement prior to EPR (odds ratio 12.0, P = .048).

CONCLUSION

Management of large segmental skeletal defects at the knee following explant using intramedullary stabilized antibiotic spacers maintain stability and result in high rates of limb salvage with conversion to an endoprosthesis.

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.

Finn/Orthopaedic Salvage System Distal Femoral Rotating-Hinge Megaprostheses in Oncologic Patients: Long-Term Complications, Reoperations, and Amputations

BACKGROUND

There is a lack of evidence regarding long-term outcomes of rotating-hinge knee prostheses with distal femoral replacement in a large oncologic patient series. In this study, we investigated the proportion of patients experiencing complications requiring surgery in the long term, as well as the cumulative incidence of implant removal/revision and amputation at 5, 10, 15, and 20 years through competing risk analyses.

METHODS

We retrospectively studied 214 patients treated with a Finn/Orthopaedic Salvage System (OSS) knee prosthesis (Zimmer Biomet) after distal femoral resection from 1991 to 2017. The study end points were postoperative complications requiring surgery. Reoperations were classified as major when there was (1) removal of the metal-body femoral component, the tibial component, or the bone-implant fixation; (2) major revision (exchange of the metal-body femoral component, the tibial component, or the bone-implant fixation); or (3) amputation. Minor reoperations were defined as all other reoperations. Competing risk analysis was used to estimate the cumulative incidence of implant removal/revision or amputation.

RESULTS

There were 312 reoperations in 113 patients (98 major reoperations in 68 patients and 214 minor reoperations). Seventeen patients (8%) required ≥5 additional operations, and 21 patients (10%) required >1 major reoperation. Although the number of reoperations decreased over time, major and minor reoperations continuously accrued after 10 years. The cumulative incidences of implant removal or revision for any reason at 5, 10, 15, and 20 years were 22.6%, 30.1%, 34.3%, and 42.5%, respectively. Although most implant removals/revisions occurred in the first 10 years, the risk persisted after 10 years, at a mean of 1.24%/year, mainly due to deep infection (1.06%/year).

CONCLUSIONS

The long-term outcomes of treatment with a Finn/OSS distal femoral rotating-hinge knee prosthesis showed it to be a durable reconstruction technique. The rate of implant removal/revisions after 10 years was gradual (1.24%/year). Deep infection remains a major late-failure mechanism, and lifetime surveillance for prosthetic problems is needed.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Bone cement as a local chemotherapeutic drug delivery carrier in orthopedic oncology: A review

Metastatic bone lesions are common among patients with advanced cancers. While chemotherapy and radiotherapy may be prescribed immediately after diagnosis, the majority of severe metastatic bone lesions are treated by reconstructive surgery, which, in some cases, is followed by postoperative radiotherapy or chemotherapy. However, despite recent advancements in orthopedic surgery, patients undergoing reconstruction still have the risk of developing severe complications such as tumor recurrence and reconstruction failure. This has led to the introduction and evaluation of poly (methyl methacrylate) and inorganic bone cements as local carriers for chemotherapeutic drugs (usually, antineoplastic drugs (ANPDs)). The present work is a critical review of the literature on the potential use of these cements in orthopedic oncology. While several studies have demonstrated the benefits of providing high local drug concentrations while minimizing systemic side effects, only six studies have been conducted to assess the local toxic effect of these drug-loaded cements and they all reported negative effects on healthy bone structure. These findings do not close the door on chemotherapeutic bone cements; rather, they should assist in materials selection when designing future materials for the treatment of metastatic bone disease.

Two Cases of Polyethylene Granuloma After Distal Femoral Endoprosthesis With All-Polyethylene Tibia

Limited literature exists on complications specific to the all-polyethylene tibial component in distal femoral replacement (DFR). Unlike in primary arthroplasty with polyethylene components, polyethylene granuloma has not been reported in DFR with an all-polyethylene tibia. Here, we report 2 cases of polyethylene granuloma in patients with primary bone sarcoma who underwent DFR with an all-polyethylene tibia. Radiologically, evidence of intraosseous granuloma formation and periprosthetic osteolysis was observed at the anterior tibial metaphysis. Both patients underwent an operative debridement of polyethylene granuloma and necrotic tissues, followed by a revision to a long-stem, cemented metal-backed tibia with impacted allograft to fill the defect. Polyethylene granuloma should be considered a differential diagnosis in the presence of a periprosthetic lytic lesion after DFR with an all-polyethylene tibial component.

Hospital Resource Utilization Associated With Endoprosthetic Reconstruction Versus Primary Arthroplasty

Endoprosthetic reconstructions of the hip and knee are currently reimbursed as primary hip and knee arthroplasty according to Current Procedural Terminology (CPT) coding guidelines. The purpose of this study was to compare hospital resources consumed by patients undergoing endoprosthetic reconstruction with those consumed by patients undergoing primary arthroplasty. The authors' hypothesis was that the former group carries more comorbidities, experiences longer length of stay (LOS), and has greater resource consumption. A retrospective review was performed of 61 patients undergoing endoprosthetic reconstruction and 745 patients undergoing primary hip or knee arthroplasty between 2015 and 2018 at a single institution. Demographic, clinical, and financial data were compared. The Charlson Comorbidity Index (CCI) was used to measure patients' health status and identify comorbidities associated with prolonged LOS through linear regression analysis. Patients who underwent endoprosthetic reconstruction had a greater than 3.5 times average LOS compared with primary arthroplasty patients: 10.81 days vs 2.94 days (P<.01). They demonstrated a higher mean CCI, higher rates of malignancy and pulmonary disease, and a wider age range. Their mean cost of care totaled $73,730.29, compared with $24,940.84 imposed by primary arthroplasty patients (P<.01). Significant predictors of LOS were malignancy status (metastatic or localized) and age younger than 50 years, with increased LOS being associated with increased cost. Patients undergoing endoprosthetic reconstruction of the hip and knee represent a fundamentally different patient population than primary arthroplasty patients based on comorbidities, variability in health status, and surgical indications. They have higher comorbidity scores and longer hospitalizations and consume more financial resources than primary arthroplasty patients. [Orthopedics. 2021;44(1):e73-e79.].

Compressive osseointegration for endoprosthetic reconstruction

This review summarizes the biomechanical concepts, clinical outcomes and limitations of compressive osseointegration fixation for endoprosthetic reconstruction. Compressive osseointe - gration establishes stable fixation and integration through a novel mechanism; a Belleville washer system within the spindle applies 400-800 PSI force at the boneimplant interface. Compressive osseointegration can be used whenever standard endoprosthetic reconstruction is indicated. However, its mode of fixation allows for a shorter spindle that is less limited by the length of remaining cortical bone. Most often compressive osseointegration is used in the distal femur, proximal femur, proximal tibia, and humerus but these devices have been customized for use in less traditional locations. Aseptic mechanical failure occurs earlier than with standard endoprosthetic reconstruction, most often within the first two years. Compressive osseointegration has repeatedly been proven to be non-inferior to standard endoprosthetic reconstruction in terms of aseptic mechanical failure. No demographic, device specific, oncologic variables have been found to be associated with increased risk of aseptic mechanical failure. While multiple radiographic parameters are used to assess for aseptic mechanical failure, no suitable method of evaluation exists. The underlying pathology associated with aseptic mechanical failure demonstrates avascular bone necrosis. This is in comparison to the bone hypertrophy and ingrowth at the boneprosthetic interface that seals the endosteal canal, preventing aseptic loosening.

What Is the 10-year Survivorship of Cemented Distal Femoral Endoprostheses for Tumor Reconstructions and What Radiographic Features Are Associated with Survival?

BACKGROUND

Aseptic loosening is one of the most common causes of revision of distal femoral endoprostheses and is considered a mid- to long-term complication. There are not many reports of 10-year survivorship free from aseptic loosening and all-cause survivorship in cemented stems. To our knowledge, there are no reports on radiographic features that are associated with aseptic loosening of these implants.

QUESTIONS/PURPOSES

(1) What is the 5- and 10-year survivorship free from aseptic loosening in patients undergoing reconstruction with a cemented distal femoral endoprosthesis after a tumor resection? (2) What is the all-cause 5- and 10-year survivorship at in these patients? (3) What radiographic features are associated with aseptic loosening at long-term follow-up?

METHODS

We performed a multicenter retrospective study reviewing aseptic loosening in cemented prostheses to determine radiographic features associated with long-term implant survivorship. Patients who underwent a cemented distal femoral reconstruction with a modular endoprosthesis after resection of a musculoskeletal tumor between 1997 and 2017 were reviewed. A total of 246 patients were identified from five institutions and met initial inclusion criteria. Of those, 21% (51) were lost to follow-up before 2 years, leaving 195 patients available for us to evaluate and analyze the survivorship and radiologic features associated with long-term implant survival. The mean (range) follow-up was 78 months (22 to 257). At the time of this analysis, 69% (135 of 195) of the patients were alive. Osteosarcoma was the most common diagnosis in 43% of patients (83 of 195), followed by metastatic carcinoma 13% (25 of 195). Fifty-six percent (110 of 195) of patients received chemotherapy; 15% (30 of 195) had radiation therapy. Aseptic loosening was diagnosed radiographically and was defined as a circumferential radiolucent line on all views, or subsidence around the stem in the absence of infection. We present 5- and 10-year Kaplan-Meier survivorship free from aseptic loosening, 5- and 10-year all-cause survivorship, and a qualitative assessment of radiographic features potentially associated with aseptic loosening (including the junctional radiolucent area, and cortical expansion remodeling). The junctional radiolucent area was defined as a radiolucent area of the bone starting at the bone-endoprosthesis junction to the tip of the femoral stem, and cortical expansion remodeling was defined as an increased cortical thickness at the stem tip. Although we wished to statistically analyze radiographic factors potentially associated with aseptic loosening, we did not have enough clinical material to do so (only nine patients developed loosening). Instead, we will report a few preliminary qualitative observations, which necessarily are preliminary, and which will need to be confirmed or refuted by future studies. We urge caution in interpreting these findings because of the very small numbers involved.

RESULTS

Kaplan-Meier survivorship free from aseptic loosening of the femoral component at 5 and 10 years were 95% (95% CI 89 to 98) and 93% (95% CI 86 to 97), respectively. Kaplan-Meier survivorship free from revision for any cause at 5 and 10 years were 74% (95% CI 65 to 79) and 64% (95% CI 49 to 70), respectively. Although the numbers were too small to analyze statistically, all patients with aseptic loosening had a junctional radiolucent area more than 20% of the total length of the stem without cortical expansion remodeling at the stem tip. No aseptic loosening was observed if there was cortical ex remodeling, a junctional radiolucent area less than 20%, or curved stems that were 13 mm or greater in diameter. The numbers of patients with aseptic loosening in this series were too small to analyze statistically.

CONCLUSIONS

Cemented distal femoral endoprostheses have a relatively low rate of aseptic loosening and acceptable projected first-decade survivorship. The presence of a radiolucent area more than 20% without cortical expansion remodeling at the stem tip may lead to aseptic loosening in patients with these implants. Close radiographic surveillance and revision surgery may be considered for progressive lucencies and clinical symptoms of pain. If revision is contemplated, we recommend using larger diameter curved cemented stems. These are preliminary and provisional observations based on a low number of patients with aseptic loosening; future studies with greater numbers of patients are needed to validate or refute these findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Fixed-hinge cemented modular implants: An effective reconstruction technique following primary distal femoral bone tumor resection. A 136-case multicenter series

BACKGROUND

Reconstruction by endoprosthesis is widespread after bone tumor resection. The design and type of fixation and of hinge remain a matter of debate. The aim of the present study was to assess survival, complications and functional results in a homogeneous series of adult patients undergoing bone defect reconstruction following distal femoral tumor resection, using a single model of fixed-hinge cemented endoprosthesis, at a minimum 5 years' follow-up.

HYPOTHESIS

The study hypotheses were that loosening and infection are the main causes of failure, and that this type of reconstruction is reliable following distal femoral resection.

PATIENTS AND METHODS

All patients aged over 17 years undergoing reconstruction using the Stanmore Mets® fixed-hinge cemented modular endoprosthesis following distal femoral resection for primary bone tumor in 4 French reference centers between 2004 and 2013 were included. Epidemiological data, MSTS functional score, clinical and radiological examination results, complications and survival with types of failure according to the Henderson classification were assessed.

RESULTS

One hundred and thirty-six patients (68 male, 68 female; mean age, 41.2 years [range, 17-77 years]) were included. Mean follow-up was 81 months [range, 61-134 months]. Thirty-two patients (38%) experienced a total 67 complications requiring surgical revision: mainly infection (n=28) or mechanical failure (n=26). Overall implant survival was 78% at 5 years. There were 30 implant failures on the Henderson classification. Mean MSTS score was 82%.

DISCUSSION

The present results are comparable to those of the literature and for other types of reconstruction. Recent meta-analyses suggest that type of hinge and of stem fixation have little effect on implant survival. International comparative studies are needed to determine the exact role of each type of reconstruction according to the patient profile.

LEVEL OF EVIDENCE

IV, multicenter retrospective series.

Establishment and validation of a nomogram model for aseptic loosening after tumor prosthetic replacement around the knee: a retrospective analysis

Background

Aseptic loosening has become the main cause of prosthetic failure in medium- to long-term follow-up. The objective of this study was to establish and validate a nomogram model for aseptic loosening after tumor prosthetic replacement around knee.

Methods

We collected data on patients who underwent tumor prosthetic replacements. The following risk factors were analyzed: tumor site, stem length, resection length, prosthetic motion mode, sex, age, extra-cortical grafting, custom or modular, stem diameter, stem material, tumor type, activity intensity, and BMI. We used univariate and multivariate Cox regression for analysis. Finally, the significant risk factors were used to establish the nomogram model.

Results

The stem length, resection length, tumor site, and prosthetic motion mode showed a tendency to be related to aseptic loosening, according to the univariate analysis. Multivariate analysis showed that the tumor site, stem length, and prosthetic motion mode were independent risk factors. The internal validation indicated that the nomogram model had acceptable predictive accuracy.

Conclusions

A nomogram model was developed for predicting the prosthetic survival rate without aseptic loosening. Patients with distal femoral tumors and those who are applied with fixed hinge and short-stem prostheses are more likely to be exposed to aseptic loosening.

Mid- to long-term results of allograft-prosthesis composite reconstruction after removal of a distal femoral malignant tumor are comparable to those of the proximal tibia

PURPOSE

To compare the outcomes of allograft-prosthesis composite for reconstruction after malignant tumors at the distal femur and proximal tibia.

METHODS

Case-control study of 24 patients with distal femur tumor and 21 with proximal tibia tumor. Union of the allograft-host interface was assessed by the International Society of Limb Salvage criteria, and complications according Henderson. Functional outcome was evaluated by the Musculoskeletal Tumor Society (MSTS) score, Western Ontario and McMaster Universities (WOMAC) score, and pain by a visual analog scale.

RESULTS

The median follow-up in the femoral group was 11.4 (range 2.3-25.0) years, and 10.1 (range 2.2-25.0) in tibial group. Incorporation of the allograft was successful in more than 90% in both groups. Tumor location was not significant predictor for allograft failure in multivariate analysis. Aseptic prosthesis loosening occurred in two patients in either group, and another patient in the tibial group had a breakage of the tibial insert. Excluding local recurrences and amputations, the prosthesis survival at 10 years was 94.1% in the femoral group, and 83.3% in the tibial group (n.s.). For the patients with preserved limb, the median MSTS score was 23.6 in the femoral group and 22.8 in tibial group (n.s.). Likewise, there were no significant differences in median WOMAC score (n.s.) or VAS pain (n.s.).

CONCLUSIONS

Allograft-prosthesis composite is an effective procedure for distal femur tumors related to the graft, prosthesis survival, and functional outcomes. The results are comparable to those for proximal tibial tumors.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

Functional and Surgical Outcomes After Endoprosthetic Reconstruction With Expandable Prostheses in Children: A Systematic Review

Treatment of bone sarcomas in children is associated with wide tumor re-section and segmental reconstruction. The optimal surgical approach is still under debate in the literature. During the past decade, the application of expandable prostheses has gained remarkable attention because it improves patients' appearance and allows limb growth preventing leg length discrepancy. A systematic review of the literature was performed to identify studies focusing on the functional and surgical outcomes of the application of expandable endoprostheses. [Orthopedics. 2019; 42(4):184-190.].

Clinical outcome of various limb salvage surgeries in osteosarcoma around knee: Megaprosthesis, extracorporeal irradiation and resection arthrodesis

Background

We evaluated the outcome and the survival rate of Limb salvage surgeries (LSSs) in osteosarcoma around knee by using megaprosthesis, ECI autograft, and modified arthrodesis of the knee with metallic plus bone cement (MAMC).

Methods

We reviewed 35 cases of osteosarcoma around the knee that was treated by megaprosthesis, ECI autograft and MAMC from 2012 to 2017. The survival, local recurrence, metastases, complications and functional MSTS score were evaluated for each operation technique. Kaplan-Meier was used to describe the survival rate for each technique.

Result

Megaprostheses group had an excellent MSTS score (78.7%), the ECI group (72.3%) and MAMC group (68.4%). Local recurrence occurred in the megaprothesis group (0%), the ECI group (9.1%) and MAMC group (20%). Infection occurred in 3 cases of ECI (13.6%) while only 2 (40%) cases in MAMC group and 1 case (12.5%) in the megaprostheses group. Aseptic loosening occurred in the megaprostheses group 1 case (12.5%) and MAMC 1 case (20%). Metastases occurred in 18.2% of the ECI group compared to 25% of the megaprostheses group and 40% of the MAMC group. The megaprosthesis group had an overall survival rate of 90.9 months, whilst the ECI group is on 94.6 months and the MAMC group was 47.2 months.

Conclusion

Megaprosthesis showed good-excellent functional outcome and survival rate. ECI that is an option in LSS has good functional outcome as well. Knee arthrodesis with MAMC it is still an option to perform LSS even in the advanced local stage of the disease.

•

Various reconstruction options are available for the reconstruction of the distal femur and proximal tibia osteosarcoma.

•

Megaprosthesis showed good-excellent functional outcome and survival rate.

•

ECI that is an option in LSS has good functional outcome as well.

•

Knee arthrodesis with MAMC it is still an option to perform LSS even in the advanced local stage of the disease.

Causes and Frequencies of Reoperations After Endoprosthetic Reconstructions for Extremity Tumor Surgery: A Systematic Review

BACKGROUND

Excision of bone tumors and endoprosthetic reconstruction allow patients early weightbearing and a potential functional advantage compared with amputation. These reconstructions do not restore the limb to normal status, however, and patients are subject to complications that may result in revision or loss of the limb. Because better understanding of these complications based on current information might help the patient and surgeon in decision-making, we undertook a systematic review of studies published on this topic.

QUESTIONS/PURPOSES

(1) What are the primary modes and proportion of failure of tumor endoprostheses in patients undergoing reconstruction after excision of primary extremity bone sarcomas?

METHODS

We systematically searched MEDLINE, Embase, and the Cochrane Library for all studies published from April 15, 1998, to April 15, 2018. Three reviewers independently reviewed studies reporting endoprosthetic reconstruction survival and events requiring revision for primary extremity bone tumors treated with endoprosthetic reconstruction for inclusion and performed independent data extraction. We excluded all studies with fewer than five patients, any systematic review/meta-analyses, and any study not reporting on primary extremity bone tumors. All discrepancies were resolved by the study's senior author. Data extracted from included studies were any reoperation event for wound dehiscence, any operative fixation for a pathologic fracture, and any revision of the primary endoprosthesis for implant wear or breakage, deep infection not amenable to prosthesis retention, or for local recurrence. We assessed the overall quality of the evidence with the Methodological Index for Non-Randomized Studies (MINORS) approach with a higher MINORS score representative of a more methodologically rigorous study with a total possible score of 16 points for noncomparative and 24 points for comparative studies. Forty-nine studies met criteria for inclusion from an initial search return of 904 studies, of which no studies were randomized controlled trials. From a total patient population of 2721, there was a mean followup of 93 months (range, 1-516 months) with loss to followup or death occurring in 447 of 2118 (21%) patients with six studies not providing loss to followup data. The mean MINORS score was 14 for prospective studies and 11 for retrospective studies.

RESULTS

Overall, there were 1283 reoperations among the 2721 (47%) patients. Reoperation for mechanical endoprosthetic events (soft tissue dehiscence or periarticular soft tissue instability, aseptic loosening, or implant wear/fracture) occurred in 907 of 2721 (33%) patients. Aseptic loosening occurred at a mean of 75 months (range, 1-376 months) in 212 of 315 patients (67%). Deep infection requiring removal of the initial prosthesis occurred in 247 of 2721 (9%) patients with deep infection occurring at a mean of 24 months (range, 1-372 months) in the 190 infections (77%) with time to infection data available. Local recurrence rates requiring revision or amputation occurred in 129 (5%) of all patients. There was an overall primary endoprosthesis survival rate without any surgical reintervention of 63% among reporting studies at a mean of 79 months followup.

CONCLUSIONS

Failures of endoprosthetic reconstructions after extremity tumor surgery are common, most often resulting from implant wear or fracture, aseptic loosening, and infection. Importantly, the aggregated data are the first to attempt to quantify the time to specific complication types within this patient population. Deep infection not amenable to endoprosthesis retention appears to occur approximately 2 years postoperatively in most patients, with aseptic loosening occurring most commonly at 75 months. Although endoprosthetic reconstruction is one of the most common forms of reconstruction after bone tumor resection, the quality of published evidence regarding this procedure is of low quality with high loss to followup and data quality limiting interstudy analysis. The quality of the evidence is low with high loss to followup and inconsistent reporting of times to reintervention events. Although the most common modes of endoprosthetic failure in this population are well known, creation of quality prospective, collaborative databases would assist in clarifying and informing important elements of the followup process for these patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Adjuvant Biophysical Therapies in Osteosarcoma

Osteosarcoma (OS) is a primary bone sarcoma, manifesting as osteogenesis by malignant cells. Nowadays, patients’ quality of life has been improved, however continuing high rates of limb amputation, pulmonary metastasis and drug toxicity, remain unresolved issues. Thus, effective osteosarcoma therapies are still required. Recently, the potentialities of biophysical treatments in osteosarcoma have been evaluated and seem to offer a promising future, thanks in this field as they are less invasive. Several approaches have been investigated such as hyperthermia (HT), high intensity focused ultrasound (HIFU), low intensity pulsed ultrasound (LIPUS) and sono- and photodynamic therapies (SDT, PDT). This review aims to summarize in vitro and in vivo studies and clinical trials employing biophysical stimuli in osteosarcoma treatment. The findings underscore how the technological development of biophysical therapies might represent an adjuvant role and, in some cases, alternative role to the surgery, radio and chemotherapy treatment of OS. Among them, the most promising are HIFU and HT, which are already employed in OS patient treatment, while LIPUS/SDT and PDT seem to be particularly interesting for their low toxicity.

Uncemented, curved, short endoprosthesis stem for distal femoral reconstruction: early follow-up outcomes

Background

Uncemented endoprosthetic knee replacement has become a mainstream treatment for malignant tumours of the distal femur. Most femoral stems, however, are straight and therefore poorly fit the anteriorly bowed curvature of the femur. To address this issue, we used a short, curved, uncemented press-fit femoral stem and evaluated its short-term outcomes after reconstruction of the distal femur.

Methods

Forty-two patients underwent distal femur replacement using curved press-fit stem. To assess the interface, we measured the axial length of the press-fit area and the perpendicular distance of the radiolucent area between the stem and bone on digital images obtained using tomosynthesis with Shimadzu Metal Artefact Reduction Technology (T-SMART). Postoperative complications and oncological outcomes were monitored at each follow-up visit.

Results

Of the 42 patients enrolled in the study, two had cancer-related deaths and one had local tumour recurrence. The minimum follow-up time of the surviving patients was 24 months, with no incidence of aseptic loosening or mechanical failure of the prosthesis. The average effective contact length between the press-fit stem and bone was 74.0 mm, with nearly undetectable radiolucent gaps between the implant and the bone on medial-lateral and anteroposterior views.

Conclusions

Over the short term, uncemented, curved, short stem provides a stable bone-prosthesis interface without any aseptic loosening.

First application of 3D design custom-made uncemented prosthetic stem for distal femoral cemented megaprosthesis revision

Objectives

3D design, which is widely used in orthopedics, can be applied for precise distal femoral megaprosthetic revision. This research aimed to present and evaluate the design, perioperative management, and mid-term clinical outcomes of a 3D design custom-made uncemented prosthetic stem.

Methods

Between January 2014 and January 2016, seven patients received 3D design custom-made uncemented prosthetic stem revision at our institution. Clinical records and radiographs were evaluated retrospectively.

Results

There were no hardware-related complications during the follow-up (average 24.3 months; range 24–48 months). The average Musculoskeletal Tumor Society (MSTS) score at the last follow-up after revision (27.7 points, range 25–28 points) was significantly higher than that before (16.0 points, range 13–18 points). In addition, the range of motion (ROM) of the affected knee, and the scores of pain, function, emotional acceptance, support, walking and gait all improved significantly. The antecurvature radian of the revision stem averaged at 3.6°. Of the seven patients, three received femoral stem revision and four received revision of the femoral stem and the femoral component; three of them used longer prostheses than the others. There were no significant differences in function between these two groups at the last follow-up after revision.

Conclusion

The 3D design custom-made prosthesis is a typical precision medicine technology in oncologic orthopedics. Characterized by its individually and precisely designed uncemented stem, it offers an alternative option for distal femoral cemented prosthesis revision. Besides the 3D design itself, the perioperative management, especially the techniques for stem implantation, and long-term follow-up are also crucial.

Implant Survival and Complication Profiles of Endoprostheses for Treating Tumor Around the Knee in Adults: A Systematic Review of the Literature Over the Past 30 Years

BACKGROUND

Endoprosthetic replacement has become the mainstream method of reconstruction after tumor resection around the knee for decades, but there is a lack of comprehensive review evaluating the implant outcomes. We performed a systematic review to analyze the implant survival and complication profiles of distal femoral replacement (DFR) and proximal tibial replacement (PTR) in adults, and to evaluate the effects of different fixation methods and hinge mechanisms.

METHODS

A systematic review of 40 studies with 4748 DFR cases and 1713 PTR cases was performed after searching the PubMed and EMBASE databases. Results of the implant longevity, complications, and other relevant data were extracted, recategorized, and analyzed. An additional review of 227 cases of Compress DFR from 6 studies was also performed.

RESULTS

The mean 5-, 10-, 15-, and 20-year implant survival rates of DFR were 78.3%, 70.1%, 61.6%, and 38.3%, slightly higher than those of PTR (75%, 60%, 55.3%, and 25.1%). Aseptic loosening (8.8%) and infection (8.5%) were the most devastating complications in DFR, while in PTR it was infection (16.8%). Cemented or cementless fixation did not significantly affect implant survival or aseptic loosening rate. Rotating-hinge mechanism might improve long-term implant survival and reduce bushing wear, but not necessarily prevented aseptic loosening. The series Kotz modular femur and tibia replacement system/Howmedica modular replacement system/global modular replacement system was one of the most durable implants. The Compress DFR showed no superiority in implant survival and complication profiles over other brands of endoprostheses.

CONCLUSION

Short-term to mid-term implant survival of adult tumor endoprostheses around the knee is acceptable but long-term outcome remains unsatisfactory. Efforts should be made in reducing loosening and infection.

Surgical and Functional Outcomes After Limb-Preservation Surgery for Tumor in Pediatric Patients: A Systematic Review

BACKGROUND

Limb-salvage surgery and segmental reconstruction for the treatment of lower extremity osseous tumors in the pediatric population have been described in the literature, but there is little consensus regarding the optimal surgical treatment for this patient population.

METHODS

A systematic review of the literature was performed to identify studies focusing on limb-salvage procedures in pediatric patients who were managed with one of three reconstructions with use of a metallic endoprosthesis, allograft, or allograft-prosthesis composite. Data were segregated according to the excised and reconstructed anatomical location (proximal part of the femur, total femur, distal part of the femur, proximal part of the tibia) and were collated to assess modes of failure and functional outcomes of each reconstruction type for each anatomic location.

RESULTS

Sixty articles met the inclusion criteria; all were Level-IV evidence, primarily consisting of small, retrospective case series. Infection was a primary mode of failure across all reconstruction types and locations, whereas allograft reconstructions were susceptible to structural failure as well. The rate of failure in the pediatric population correlated well with previously published results for adults. The incidence of subsequent amputation was lower in the pediatric population (5.2%) than has been reported in adults (9.5%) (p = 0.013). Meaningful growth of expandable metallic endoprostheses was reported in the literature, with an overall rate of leg-length discrepancy of 13.4% being noted at the time of the latest follow-up. The Musculoskeletal Tumor Society (MSTS) questionnaire was the most consistently used outcome measure in the literature, with average scores ranging from 71.0% to 86.8%, depending on reconstruction type and anatomic location.

CONCLUSIONS

The current state of the literature detailing the surgical and functional outcomes of segmental reconstruction for the treatment of pediatric bone tumors is limited to Level-IV evidence and is complicated by under-segregation of the data by age and anatomical location of the reconstruction. Despite these limitations, pediatric limb-salvage surgery demonstrates satisfactory initial surgical and functional outcomes.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Gait Analysis in Patients with Wide Resection and Endoprosthesis Replacement Around the Knee

BACKGROUND

Limb salvage surgery with endoprosthesis for bone tumor around the knee is reported to have good functional and oncological outcomes. However, the functional assessment using musculoskeletal tumor society (MSTS) and Toronto extremity scoring system remains subjective. We performed gait analysis as an objective assessment of their functional outcome.

MATERIALS AND METHODS

Gait analysis was performed in 20 patients with endoprosthesis replacement around the knee. The temporal parameters assessed during gait analysis were walking velocity, stride length, duration of stance, and goniometry of the knee. These parameters were compared with the functional outcome score of the MSTS.

RESULTS

The mean free-paced walking velocity was 0.91 m/s (normal is 1.33 m/s), which was 68% lower than normal gait. The stride length and stance phase were shorter for the affected limb compared to normal (P < 0.05). However, the gait was symmetrical with no difference in stride length (P = 0.148), velocity (P = 0.918), knee flexion (P = 0.465), and knee extension (P = 0.321) between the affected and unaffected limbs. Sixteen patients demonstrated stiff knee gait, two had a flexed knee gait, and only two patients had normal gait during the stance phase. The mean MSTS score was 21. There was significant correlation between overall MSTS scores (P = 0.023), function (P = 0.039), and walking scores (P = 0.007).

CONCLUSION

Limb salvage surgery with endoprosthesis reconstruction around the knee gives good functional outcome, both objectively and subjectively, as evidenced by the symmetrical gait pattern and significant correlation with MSTS score. Despite decreased walking velocity, stride length, and stance phase of the operated limb, the patient still has a symmetrical gait.

Pedicled Rotational Medial and Lateral Gastrocnemius Flaps: Surgical Technique

Gastrocnemius flaps have been used for decades to reconstruct defects of the proximal tibia and knee. They have proven to be useful in the soft-tissue reconstruction of defects caused by trauma, tumors, and infections about the knee, and the reconstruction of extensor mechanism discontinuity with and without total joint arthroplasty. The flaps have low failure rates and a distinct proximally based blood supply that allows them to be elevated and rotated up to 15 cm above the level of the knee joint. The vascular anatomy is reproducible because rotational flaps do not require microvascular anastomosis. An understanding of the applied surgical anatomy, approaches, and utility of the gastrocnemius flap makes the technique a useful tool for the orthopaedic surgeon when plastic surgery assistance is not readily available.

Megaprosthesis of the knee in tumor and revision surgery

The introduction of multidisciplinary approach with chemo and radiotherapy, the advances in surgical and the improvements of diagnostic techniques allowed limb salvage surgery in most cases of bone sarcomas instead of amputation. Modular megaprostheses are the most common method of reconstruction after segmental resection of the long bones in the extremities for their availability, immediate fixation, early weight bearing, good function. Despite the advances in materials and implant designs, these systems have an high incidence of complications. Aim of this study was to report the experience on mega-prostheses implanted around the knee in tumor and revision surgery to analyze: the most frequent used current systems, the problems of stems fixation, extensor mechanism reconstructions in proximal tibia resections and the preservation of growth of the lower extremity in children.

Megaprosthesis of the knee in tumor and revision surgery

The introduction of multidisciplinary approach with chemo and radiotherapy, the advances in surgical and the improvements of diagnostic techniques allowed limb salvage surgery in most cases of bone sarcomas instead of amputation. Modular megaprostheses are the most common method of reconstruction after segmental resection of the long bones in the extremities for their availability, immediate fixation, early weight bearing, good function. Despite the advances in materials and implant designs, these systems have an high incidence of complications. Aim of this study was to report the experience on mega-prostheses implanted around the knee in tumor and revision surgery to analyze: the most frequent used current systems, the problems of stems fixation, extensor mechanism reconstructions in proximal tibia resections and the preservation of growth of the lower extremity in children. (www.actabiomedica.it)