Aseptic loosening is uncommon with uncemented proximal tibia tumor prostheses

Endoprosthetic replacement of the proximal tibia for oncological conditions

Aims

The proximal tibia (PT) is the anatomical site most frequently affected by primary bone tumours after the distal femur. Reconstruction of the PT remains challenging because of the poor soft-tissue cover and the need to reconstruct the extensor mechanism. Reconstructive techniques include implantation of massive endoprosthesis (megaprosthesis), osteoarticular allografts (OAs), or allograft-prosthesis composites (APCs).

Methods

This was a retrospective analysis of clinical data relating to patients who underwent proximal tibial arthroplasty in our regional bone tumour centre from 2010 to 2018.

Results

A total of 76 patients fulfilled the inclusion criteria and were included in the study. Mean age at surgery was 43.2 years (12 to 86 (SD 21)). The mean follow-up period was 60.1 months (5.4 to 353). In total 21 failures were identified, giving an overall failure rate of 27.6%. Prosthesis survival at five years was 75.5%, and at ten years was 59%. At last follow-up, mean knee flexion was 89.8° (SD 36°) with a mean extensor lag of 18.1° (SD 24°). In univariate analysis, factors associated with better survival of the prosthesis were a malignant or metastatic cancer diagnosis (versus benign), with a five- and ten-year survival of 78.9% and 65.7% versus 37.5% (p = 0.045), while in-hospital length of stay longer than nine days was also associated with better prognosis with five- and ten-year survival rates at 84% and 84% versus 60% and 16% (p < 0.001). In multivariate analysis, only in-hospital length of stay was associated with longer survival (hazard ratio (HR) 0.23, 95% confidence interval (CI) 0.08 to 0.66).

Conclusion

We have shown that proximal tibial arthroplasty with endoprosthesis is a safe and reliable method for reconstruction in patients treated for orthopaedic oncological conditions. Either modular or custom implants in this series performed well.

Cite this article: Bone Jt Open 2022;3(9):733–740.

Short-term clinical outcomes of Kyocera Modular Limb Salvage System designed cementless stems for the endoprosthetic reconstruction of lower extremities: a Japanese Musculoskeletal Oncology Group multi-institutional study

BACKGROUND

The high rate of aseptic loosening of cemented stems has led to their frequent use in endoprosthetic reconstruction. However, problems, such as stem breakage and stress shielding at the insertion site, remain. The Japanese Musculoskeletal Oncology Group (JMOG) has developed Kyocera Modular Limb Salvage System (KMLS) cementless stems with a unique tapered press-fit and short fixation design. This study aimed to clarify the short-term postoperative outcomes of this prosthesis and validate the stem design.

METHODS

One hundred cases of KMLS cementless stems (51 male patients; median age, 49 years; mean follow-up period, 35 months), with a minimum follow-up of 2 years, for the proximal femur (PF), distal femur (DF), and proximal tibia were prospectively registered for use. Prosthesis survival, complication rates, postoperative functional, and radiographical evaluation were analyzed. Complications or failures after insertion of the KMLS endoprostheses were classified into five types and functional results were analyzed according to the MSTS scoring system at postoperative 1 year. The diaphyseal interface and anchorage were graded by the ISOLS system at postoperative 2 years.

RESULTS

The overall prosthesis survival rates at 2 and 4 years were 88.2 and 79.6%, respectively. The prosthesis-specific survival rate excluding infection and tumor recurrence was 90.2 and 87.9%, respectively. Younger age (p = 0.045) and primary tumor (p = 0.057) were associated with poor prognosis of prosthesis-specific survival excluding infection and tumor recurrence. Complications were observed in 31 patients, 13 patients underwent revision surgery. The mean MSTS functional score at 1 year postoperatively was 68%. Early implant loosening was significantly more common in the DF (p = 0.006) and PF/DF straight stem (p = 0.038). The ISOLS radiographic evaluation at 2 years after surgery revealed good bone remodeling and anchorage in most cases (bone remodeling: 90% / excellent and good, anchorage: 97% / excellent and good).

CONCLUSIONS

Tumor endoprosthesis long-term fixation to the diaphysis of the lower extremity remains challenging. The KMLS cementless stem with a unique tapered press fit design showed good short-term results in maintaining bone stock. To prevent early loosening, a curved stem should be used in PF and DF, but long-term follow-up is necessary.

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.

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

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

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.

The effects of length of femoral stem on aseptic loosening following cemented distal femoral endoprosthetic replacement in tumour surgery

PURPOSE

Aseptic loosening is a common prosthetic failure mode. The purpose of this study was to identify dose-response relationship between length of femoral stem and aseptic loosening.

METHODS

We collected data of patients who underwent distal femoral prosthetic replacements at our institution from 2001 to 2017. Cox regression and two-piecewise regression model were used to analyze the associations between stem length and aseptic loosening.

RESULTS

Significant association of length of femoral stem with aseptic loosening was observed in multivariate model and a non-linear relationship could be found from the smoothed curve. In two-piecewise model, an inflection point was calculated to be 143 mm. On the left of the inflection point, every 1 mm increase in the length of stem indicated that the risk of aseptic loosening could be reduced by 6%.

CONCLUSION

There was a significant non-linear relationship between the length of femoral stem and aseptic loosening, and the inflection point was 143 mm.

Midterm Success of a Custom, Non-Fluted, Diaphyseal, Press-Fit Stem Used With a Tumor Megaprosthesis System

BACKGROUND

High rates of aseptic loosening with cemented prostheses have led to increased utilization of uncemented stems in the setting of megaprosthetic reconstruction. Theoretic concerns of rotational instability resulted in early stem designs with de-rotational mechanisms such as flutes or side plates. However, these designs have their own associated complications, and mechanical data suggest they are unnecessary. The purpose of this study is to evaluate outcomes and survivorship of an unfluted diaphyseal press-fit stem in the setting of megaprosthetic reconstruction.

METHODS

Forty-five patients (46 stems), with a minimum 3-year follow-up, underwent reconstruction using 1 of 2 fully porous coated, unfluted, press-fit stems between 2005 and 2013: revision stem with adapter to the megaprosthesis (revision stem), or custom megaprosthesis stem (custom stem). Complications were described using the Henderson classification system, and subanalyses evaluated stem-related failures and survival. Radiographic evaluation of stem fixation was determined via evidence of bone bridging, spot welding, resorption, subsidence, and pedestal formation. Four patients had early stem removal for local recurrence or infection and were thus excluded from the radiographic analyses.

RESULTS

Twenty-eight femoral (15 revision stem, 13 custom stem) and 14 tibial (6 revision stem, 8 custom stem) stems were reviewed. Average follow-up was 81 months (range, 42-140 months). Revision for implant-related complications occurred in 7 of 41 (17%), all in revision stems (3 adapter failures, 4 polyethylene wear). At final follow-up, all stems were retained without evidence of aseptic loosening, although 7 of 41 (17%) exhibited mild stress shielding.

CONCLUSION

A non-fluted, press-fit stem used with a tumor prosthesis provided a stable bone-prosthesis interface at midterm follow-up.

Total femur prosthesis in oncological and not oncological series. Survival and failures

Total femur prosthesis (TFP) can be used in both oncological and prosthetic revision surgery. A retrospective analysis of 32 patients receiving a TFP at a single Center between 2002 and 2018 was performed. The average follow-up was 60 months. Revision implant free survival (RIFS) of the implants was 87% at 5 and 10 years and 72% at 15 years. Overall implant survival (OIS) of the prosthesis was 90% at 5, 10 and 15 years. Complications observed: two soft tissue failures, two infection failure and one tumor progression failure.

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.

Proximal Tibial Reconstruction After Tumor Resection: A Systematic Review of the Literature

BACKGROUND

The proximal part of the tibia is a common location for primary bone tumors, and many options for reconstruction exist following resection. This anatomic location has a notoriously high complication rate, and each available reconstruction method is associated with unique risks and benefits. The most commonly utilized implants are metallic endoprostheses, osteoarticular allografts, and allograft-prosthesis composites. There is a current lack of data comparing the outcomes of these reconstructive techniques in the literature.

METHODS

A systematic review of peer-reviewed observational studies evaluating outcomes after proximal tibial reconstruction was conducted, including both aggregate and pooled data sets and utilizing a Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) review for quality assessment. Henderson complications, amputation rates, implant survival, and functional outcomes were evaluated.

RESULTS

A total of 1,643 patients were identified from 29 studies, including 1,402 patients who underwent reconstruction with metallic endoprostheses, 183 patients who underwent reconstruction with osteoarticular allografts, and 58 patients who underwent with reconstruction with allograft-prosthesis composites. The mean follow-up times were 83.5 months (range, 37.3 to 176 months) for the metallic endoprosthesis group, 109.4 months (range, 49 to 234 months) for the osteoarticular allograft group, and 88.8 months (range, 49 to 128 months) for the allograft-prosthesis composite reconstruction group. The mean patient age per study ranged from 13.5 to 50 years. Patients with metallic endoprostheses had the lowest rates of Henderson Type-1 complications (5.1%; p < 0.001), Type-3 complications (10.3%; p < 0.001), and Type-5 complications (5.8%; p < 0.001), whereas, on aggregate data analysis, patients with an osteoarticular allograft had the lowest rates of Type-2 complications (2.1%; p < 0.001) and patients with an allograft-prosthesis composite had the lowest rates of Type-4 complications (10.2%; p < 0.001). The Musculoskeletal Tumor Society (MSTS) scores were highest in patients with an osteoarticular allograft (26.8 points; p < 0.001). Pooled data analysis showed that patients with a metallic endoprosthesis had the lowest rates of sustaining any Henderson complication (23.1%; p = 0.009) and the highest implant survival rates (92.3%), and patients with an osteoarticular allograft had the lowest implant survival rates at 10 years (60.5%; p = 0.014).

CONCLUSIONS

Osteoarticular allograft appears to lead to higher rates of Henderson complications and amputation rates when compared with metallic endoprostheses. However, functional outcomes may be higher in patients with osteoarticular allograft. Further work is needed using higher-powered randomized controlled trials to definitively determine the superiority of one reconstructive option over another. In the absence of such high-powered evidence, we encourage individual surgeons to choose reconstructive options based on personal experience and expertise.

LEVEL OF EVIDENCE

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

Mechanisms of failure and survival of total femoral endoprosthetic replacements

AIMS

The aim of this study was to evaluate the prosthesis characteristics and associated conditions that may modify the survival of total femoral endoprosthetic replacements (TFEPR).

PATIENTS AND METHODS

In all, 81 patients treated with TFEPR from 1976 to 2017 were retrospectively evaluated and failures were categorized according to the Henderson classification. There were 38 female patients (47%) and 43 male patients (53%) with a mean age at diagnosis of 43 years (12 to 86). The mean follow-up time was 10.3 years (0 to 31.7). A survival analysis was performed followed by univariate and multivariate Cox regression to identify independent implant survival factors.

RESULTS

The revision-free survival of the implant was 71% at five years and 63.3% at ten years. Three prostheses reached 15 years without revision. The mean Musculoskeletal Tumor Society score in the group was 26 (23 to 28). The mechanisms of failure were infection in 18%, structural failures in 6%, tumour progression in 5%, aseptic loosening in 2%, and soft-tissue failures in 1%. Prostheses used for primary reconstruction after oncological resections had lower infection rates than revision implants (8% vs 25%; p = 0.001). The rates of infection in silver-coated and non-silver-coated prosthesis were similar (17.4% vs 19.%; p = 0.869). The incidence of hip dislocation was 10%. Rotating hinge prosthesis had a lower failure rate than fixed hinge prosthesis (5.3% vs 11%). After Cox regression, the independent factors associated with failures were the history of previous operations (hazard ratio (HR) 3.7; p = 0.041), and the associated arthroplasty of the proximal tibia (HR 3.8; p = 0.034). At last follow-up, 11 patients (13%) required amputation.

CONCLUSION

TFEPR offers a reliable reconstruction option for massive bone loss of the femur, with a good survival when the prosthesis is used as a primary implant. The use of a rotating hinge at the knee and dual mobility bearing at the hip may be adequate to reduce the risk of mechanical and soft-tissue failures. Infection remains the main concern and there is insufficient evidence to support the routine use of silver-coated endoprosthesis. Cite this article: Bone Joint J 2019;101-B:522-528.

Fitness, Function, and Exercise Training Responses after Limb Salvage With a Lower Limb Megaprosthesis: A Systematic Review

OBJECTIVE

To describe the fitness, function, and exercise training responses of patients following reconstruction of the lower limb with a total femoral (TF), proximal femoral (PF), distal femoral (DF), or proximal tibial (PT) megaprosthesis. TYPE: Systematic review.

LITERATURE SURVEY

Five research databases were searched systematically for original studies published in English from 2006 to 2017 that reported fitness, functioning, or exercise training responses for one or more of the four types of lower limb megaprosthesis listed above.

METHODOLOGY

Methodologic quality was assessed using a 22-item modified STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist.

SYNTHESIS

Of the 5342 articles retrieved, 28 met the inclusion criteria. Thirteen studies reported fitness outcomes, primarily in PT, with none in TF. Impaired knee extensor strength of the affected limb was reported following limb salvage with PF, DF, and PT megaprosthetics. Impaired flexibility was reported following limb salvage with DF and PT megaprosthetics. Functional outcomes were described in all studies and were most commonly reported using the Musculoskeletal Tumor Society (MSTS) system score. Results indicated no clear difference in functional outcomes between megaprosthesis locations. No studies evaluated exercise training responses.

CONCLUSIONS

This review identified impairments of lower limb strength and flexibility following limb salvage with a lower limb megaprosthesis. Similarity in functional outcomes for all four reported megaprosthetic locations may indicate a lack of sensitivity in outcome measures, including the absence of items assessing higher-level functioning. Exercise interventions that aim to improve fitness and function in this population have not been evaluated but are required given increasing 5-year survival rates.

LEVEL OF EVIDENCE

I.

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.

Implant and limb survival after resection of primary bone tumors of the lower extremities and reconstruction with mega-prostheses fifty patients followed for a mean of forteen years

PURPOSE

Previous studies reported variable outcome and failure rates after mega-prosthetic reconstructions in the lower extremities. The purpose of this study was to make a long-term single-center evaluation of patients treated with limb-sparing surgery and reconstruction with mega-prostheses in the lower extremities.

METHODS

We identified 50 patients (osteosarcoma (n = 30), chondrosarcoma (n = 9), osteoclastoma (n = 6), Ewing sarcoma (n = 4), angiosarcoma (n = 1)), who underwent limb-sparing reconstruction of the lower extremities (proximal femur (n = 9), distal femur (n = 29), proximal tibia (n = 9), and the entire femur (n = 3)) between 1985 and 2005. Surviving patients not lost to follow-up were evaluated using the MSTS score. Causes of failure were classified according to the Henderson classification. Kaplan-Meier survival analysis was used for evaluation of patient, prosthesis, and limb survival.

RESULTS

Twenty-eight patients were alive at follow-up. Fifty-four percent had revision surgery (n = 27). The ten year patient survival was 60% (95%CI 46-74%); the ten year implant survival was 24% (95%CI 9-41%), and the ten year limb survival rate was 83% (95%CI 65-96%). Type 1 failure occurred in 9%, type 2 in 16%, type 3 in 28%, type 4 in 18%, and type 5 in 3%. Mean MSTS score was 21 (range, 6-30), representing a median score of 71%.

CONCLUSIONS

Our long-term results with mega-prostheses justify the use of limb-salvage surgery and prosthetic reconstruction. Our results are fully comparable with other findings, with regard to limb and prosthesis survival, but also with regard to functional outcome.

Survival, complications and functional outcomes of cemented megaprostheses for high-grade osteosarcoma around the knee

PURPOSE

We initiated a retrospective study on the long-term survival of cemented endoprostheses for bone tumours around the knee to answer the following questions: (1) What was the survival of these patients? (2) What was the overall survival of cemented prostheses around the knee? (3) What types of failures were observed in these reconstructions? (4) Did the survival and complications vary according to the site of the implant? (5) What was the functional result after cemented prosthesis replacement around the knee?

METHODS

From January 2006 to December 2013, 108 consecutive patients with an average age of 25 years, who had mature bone development as evidenced by imaging examinations, underwent 108 cemented endoprosthetic knee replacements for osteosarcoma resection. All patients received neoadjuvant chemotherapy using a multi-drug protocol consisting of high dose methotrexate (HDMTX), doxorubicin (ADM), cisplatin (DDP) and high dose ifosfamide (HDIFO). When extensor mechanism reconstruction was required, we ran nonabsorbable sutures through designated holes in the tibial component to fix detached hamstrings and the remaining ligaments in an imbricated fashion as well as reinforced the reconstruction with a medial gastrocnemius flap. Seventy-two (72/108, 66.7%) lesions were located in the distal femur and 36 (36/108, 33.3%) lesions at the proximal tibias. Nineteen patients were staged as IIA and 89 as IIB according to the Enneking staging system. The average follow-up was 53.3 months (range 12-125 months), with a minimum oncological follow-up of one year. Survival, prosthetic failure, complications and functional outcomes were recorded and reassessed at every visit after the primary operation.

RESULTS

At the final follow-up, the oncologic results showed that 33 patients died from metastases, and local recurrence occurred in ten patients. The estimated overall five-year and eight-year survival rates were 71% (95% CI: 62.4-79.65%) and 67.2% (95% CI: 58-76.4%), respectively. In this study, a total of 51 complications occurred in 45 patients, and at the end of follow-up, 59 patients had prostheses in situ. The estimated overall five-year and eight-year implant survival rates were 77.7% (95% CI: 67.9-87.5%) and 54.5% (95% CI: 31.4-77.6%), respectively, when patients who died with their original prostheses were censored. In total, 21 (21/108, 19.4%) implants failed, five due to infections (5/21), eight due to aseptic loosening (8/21), four due to local recurrence (4/21), three due to structural failure (3/21) and one due to soft tissue failure (1/21). The average Musculoskeletal Tumor Society Score (MSTS) at the most recent follow-up was 22.9 (9-30) points on a 30-point scale, which indicated an excellent or good functional outcome. Analysis of the results based on implant site revealed a slight difference of the estimated five-year prosthesis survival between implants located in the distal femur and those located in the proximal tibia [86.1% (95% CI: 75.5-97%) versus 66.9% (95% CI: 49.8-83.9%); P = 0.09]. However, the functional outcomes and complication rates of prostheses located in the distal femur were both better than those located in the proximal tibia.

CONCLUSIONS

With effective management strategies for complications, cemented endoprosthetic reconstruction of the proximal tibia and distal femur using an extensor mechanism reconstruction technique provides a reliable method of reconstruction following tumour resection around the knee. Level of Evidence Level IV, therapeutic study.

Component Fracture in the Kotz Modular Femoral Tibial Reconstruction System: An Under-Reported Complication

BACKGROUND

Primary bone tumors of the femur are commonly reconstructed using an endoprosthesis. Different modes of implant failure have been described, including structural failure; although uncommon, this may be an under-reported complication. The purpose of this study is to examine the rates and risk factors for implant fracture of the Kotz Modular Femoral Tibial Reconstruction system (KMFTR).

METHODS

Two hundred twenty-one patients (95 women and 126 men) who underwent a KMFTR reconstruction were reviewed. Twenty-seven patients (12%) sustained a prosthetic fracture. The mean time to fracture was 7 years postoperatively. The fractured component most commonly involved the distal femur (n = 21) and a screw hole in the stem (n = 12). In patients with stem fractures (n = 21), the mean intramedullary stem diameter was 12 mm and the mean extramedullary component length was 18 cm.

RESULTS

Compared to patients who did not fracture, those with a prosthetic fracture had a significantly smaller stem diameter (12 vs 14 mm, P = .001) and a significantly longer extramedullary component length (18 vs 15 cm, P = .04). There was no difference between the preoperative and postoperative Toronto Extremity Salvage Scores (P = .98), Musculoskeletal Tumor Society 87 (P = .78), or Musculoskeletal Tumor Society 93 (P = 1.0) ratings for patients with or without a prosthetic fracture.

CONCLUSION

This study shows that fracture is an under-reported complication associated with the KMFTR stem. We identified an endoprosthetic component fracture rate of 12%. Patients with smaller stem diameter and longer resection lengths were more likely to sustain a stem fracture. Subsequent revision provides a durable means of reconstruction, with no significant loss of patient function.

Is total femoral replacement for non-oncologic and oncologic indications a safe procedure in limb preservation surgery? A single center experience of 22 cases

Background

Several surgical options for the reconstruction of massive bone defects have been described and include biologic methods with autografts and allografts, and the use of tumor endoprostheses (total femoral replacement, TFR). Several types of modular TFR are available, but nevertheless unpredictable outcomes and high complication rates have been described from most authors. The present study aims to compare results after TFR performed with modular total femur prosthesis MML (Fa. ESKA/Orthodynamics) in patients with and without malignant disease.

Methods

Retrospective chart review and functional investigation (Musculoskeletal Tumor Society (MSTS) score, Harris Hip Score (HHS), Oxford Knee Score (OKS), SF-12 Health Survey, and failure classification according to Henderson) of TFR cases from 1995 to 2011. Indications for TFR were malignant tumor resection from the femur (n = 9, Group A) or failure of a revision arthroplasty without history of malignant disease (n = 13, Group B).

Results

Thirty-six patients were treated during the study period, of whom 22 could be investigated clinically after a mean follow-up of 63 months. Overall failure rate for TFR was 59.1%, leading to 38 surgical revisions. The most common failure mechanisms were Type I (soft tissue), followed by Type IV (infection) and Type III (mechanical failure). Mean MSTS score out of 30 was 13 (range 1–25), with significantly higher scores in Group A (mean 19, range 3–25) than Group B (mean 9, range 1–15).

Conclusion

TFR is an established procedure to restore femoral integrity. However, complication rates are considerably high, and depend mainly on the age at initial reconstruction.

Intercalary allograft augmented with intramedullary cement and plate fixation is a reliable solution after resection of a diaphyseal tumour

AIMS

Intercalary allografts following resection of a primary diaphyseal tumour have high rates of complications and failures. At our institution intercalary allografts are augmented with intramedullary cement and fixed using compression plating. Our aim was to evaluate their long-term outcomes.

PATIENTS AND METHODS

A total of 46 patients underwent reconstruction with an intercalary allograft between 1989 and 2014. The patients had a mean age of 32.8 years (14 to 77). The most common diagnoses were osteosarcoma (n = 16) and chondrosarcoma (n = 9). The location of the tumours was in the femur in 21, the tibia in 16 and the humerus in nine. Function was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system and the Toronto Extremity Salvage Score (TESS). The survival of the graft and the overall survival were assessed using the Kaplan-Meier method.

RESULTS

The median follow-up was 92 months (4 to 288). The mean MSTS 87 score was 29.1 (19 to 35), the mean MSTS 93 score was 82.2 (50 to 100) and the mean TESS score was 81.2 (43 to 100). Overall survival of the allograft was 84.8%. A total of 15 patients (33%) had a complication. Five allografts were revised for complications and one for local recurrence.

CONCLUSION

Intercalary allografts augmented with intramedullary cement and compression plate fixation provide a reliable and durable method of reconstruction after the excision of a primary diaphyseal bone tumour, with high levels of function and satisfaction. Cite this article: Bone Joint J 2017;99-B:973-8.

[Effectiveness of unicompartment allografts replacement for bone tumor around the knee]

Objective

To analyze the effectiveness of unicompartment allografts replacement for reconstructing bone defect after bone tumor resection around knee.

Methods

Between January 2007 and January 2014, a total of 9 patients received unicompartment allografts replacement to treat bone tumor around the knee, including 6 males and 3 females, with an average age of 25.8 years (range, 17-38 years). There were 7 patients with bone giant cell tumor (postoperative recurrence of bone giant cell tumor in 1 case) and 2 patients with chondromyxoid fibroma. The tumors were located at the distal femur in 7 cases and proximal tibia in 2 cases, and the tumors were almost at the lateral limbs. The symptom duration was 2-5 months (mean, 3.2 months). The size of lesion ranged from 6 cm×2 cm to 9 cm×4 cm by X-ray film and MRI; and the metastasis was excluded by CT. The length of the allograft was 8.0-9.2 cm (mean, 8.6 cm).

Results

The intraoperative blood loss volume was 400-550 mL (mean, 480 mL); and 0-3 U of erythrocyte was transfused after operation. The continuous exudate of incision occurred in 1 patient, and cured after 3 months; the other incisions healed primarily at 2 weeks after operation. All patients were followed up 3-10 years (mean, 6 years). No operation area infection, allograft bone poor healing or rupture was found. At 1 year after operation, the knee range of motion was 90-110° (mean, 100°); the Musculoskeletal Tumor Society score was 24-29 (mean, 26). Low density area (osteolysis) was found in 6 allografts; no articular surface collapse, hairline fracture, or fracture was found in patients; callus formation was observed in the contact surface between the allograft and the host bone, and the cortical bone showed good continuity.

Conclusion

Unicompartment allografts replacement can provide good support and function in terms of bone tumor resection, and achieve good effectiveness by biological reconstruction.

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)

Distal femoral replacement with the MML system: a single center experience with an average follow-up of 86 months

Background

The aim of this study was to compare the functional outcomes and complication rates after distal femoral replacement (DFR) performed with the modular Munich-Luebeck (MML) modular prosthesis (ESKA/Orthodynamics, Luebeck, Germany) in patients being treated for malignant disease or failed total knee arthroplasty.

Methods

A retrospective review of patient charts and a functional investigation (involving Musculoskeletal Tumor Society Score [MSTS], American Knee Society Score [AKSS], Oxford Knee Score [OKS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], Toronto Extremity Salvage Score [TESS], the 12-Item Short-Form [SF-12] Health Survey, and a failure classification system developed by Henderson et al.) of DFR cases from 2002 to 2015 were conducted. The indications for DFR were malignant tumor resection in the femur (n = 20, group A) or failure of revision total knee arthroplasty without a history of malignant disease (n = 16, group B).

Results

One-hundred and twenty-nine patients were treated during the study period. Of these, 82 were analyzed for complications and implant-survival. Further, 36 patients were available for functional assessment after a mean follow-up of 86 months (range: 24–154). There were 75 complications in total. The overall failure rate for DFR was 64.6% (53/82 patients). The most common failure mechanisms were type III (mechanical failure), followed by type I (soft tissue) and type II (aseptic loosening). The mean MSTS score (out of 30) was 17 for group A and 12 for group B. All the clinical outcome scores revealed an age-dependent deterioration of function.

Conclusion

DFR is an established procedure to restore distal femoral integrity. However, complication rates are high. Post-procedure functionality depends mainly on the patient’s age at initial reconstruction.

Short- to long-term follow-up of total femoral replacement in non-oncologic patients

BACKGROUND

Compromised bone stock and heavily impaired structural integrity after multiple endoprosthetic revision surgeries can lead to a comparable condition as encountered in musculoskeletal tumor surgery. Total femoral replacement (TFR) can restore femoral integrity and allow patients to resume ambulation. Even though several authors reported their results of TFR, so far many questions are still on debate: Which patients are at risk to experience low functional outcome? Do complications and clinical outcome after TFR depend on the indication for the surgery (e.g. periprosthetic fractures or aseptic loosening) or the age of the patients? The purpose of the present study was to compare complication rates after TFR performed with modular total femur prosthesis MML (Fa. ESKA/Orthodynamics) in patients without malignant disease.

METHODS

We conducted a retrospective chart review and functional investigation of patients treated with a TFR for non-oncologic conditions from 1995 to 2015 and a minimum follow-up of 2 years. Complications were recorded according to the Henderson-Classification; outcome was evaluated with established clinical scores. The indication for TFR was periprosthetic fracture (Group A, n = 11) or aseptic loosening (Group B, n = 7) with massive bone defect of the femur deemed unsuitable for conventional arthroplastic or biologic reconstruction.

RESULTS

Eighteen patients matched the inclusion criteria and could be investigated clinically after a mean follow-up of 80 months (range: 28-132). Before TFA, all patients had previously undergone multiple operations (range: 1-8). The overall failure rate for any reason was 72% (n = 13/18), leading to a total of 37 surgical revisions with total exchange of TFR in 22% (n = 4/18). Most common failure mechanism was Type I (soft tissue), followed by Type IV (infection) and Type III (mechanical failure). According to Enneking's functional evaluation method (MSTS-Score), the function ranged from 1 to 15 with a mean of 10 ± 4 out of 30.

CONCLUSION

TFR is a salvage procedure to restore mechanical integrity and regain functional ability after extensive femoral bone loss. Outcome of the patients in the present study did mainly depend on the age at reconstruction and not on the indication for TFR.

Modular cementless prosthetic reconstruction after resection of lower extremity malignant tumor

INTRODUCTION

The aim of the study is to report the preliminary clinical and functional outcomes of a modular cementless tumor resection prosthesis system (Megasystem-C^®, Waldemar Link GmbH&Co. KG, Hamburg, Germany) in patients undergoing limb salvage surgery with wide resection in a lower extremity primary or metastatic malignant bone tumor.

MATERIAL AND METHODS

Fifty-two consecutive patients (33 male and 19 female; mean age 37.1 years (range, 16 to 79) with primary or metastatic lower extremity malignant bone tumor who underwent wide resection and reconstruction with cementless Megasystem-C^® system were included in the study. Patients were analyzed for age at diagnosis, gender, type and localization of the tumor, time of follow-up, patient and prosthesis survival, complications, oncological and functional outcomes.

RESULTS

Mean follow-up time was 43.2 months (range, 8 to 66). Cumulative patient survival rate was 92.3 percent and cumulative prosthetic survival rate was 65.4 percent. 18 complications were recorded and 9 of them required revision (17.3 percent). Mean overall Musculoskeletal Tumor Society score score was 72.7 percent (range, 52 to 86). Subgroup analyzes demonstrated no difference in complication rates, overall patient or prosthetic survivals. Functional scores according to age, diagnosis and location of the reconstruction also were not significantly different.

CONCLUSION

The preliminary short-term follow-up results revealed that, the new generation modular cementless endoprosthetic system offers promising clinical and functional outcomes with reasonable complication rates.

LEVEL OF EVIDENCE

Level IV, Therapeutic study.

Survival, failure modes and function of combined distal femur and proximal tibia reconstruction following tumor resection

BACKGROUND

Tumor spread to the knee joint or skip metastasis to the adjacent bones of the knee require reconstruction with combined distal femur and proximal tibia replacements. The literature on implant survival and failure modes with this type of reconstruction is sparse. The goals of this study were to determine the implant survival, the different failure modes and the functional outcome of this megaendoprosthetic reconstruction.

PATIENTS AND METHODS

Thirty-nine patients with combined distal femur and proximal tibia reconstruction were retrospectively reviewed. Median follow-up was 8.8 years (quartiles 4.7-15.5 years). Twenty-one patients received combined distal femur and proximal tibia reconstruction as a primary mode of reconstruction, 18 patients as revision surgery after failed tumor prosthesis. For survival estimations, competing risk analyses were performed.

RESULTS

The revision-free survival at five years was 42% (95% CI 22%-56%) and implant survival with exchange of the original implant was 54% (95% CI 35%-68%). Five-year revision-free survival for soft tissue failure was 72% (95% CI 52%-84%), for infection 67% (95% CI 48%-80%), for structural failure 82% (95% CI 63%-91%), for aseptic loosening and tumor progression 97% (95% CI 82%-99%), respectively. Patients with revision surgery had higher risk for infection (p < 0.001), structural failure (p = 0.037) and shorter revision-free- (p = 0.025) and implant-survival (p = 0.006). Limb survival at 20 years was 94%. Mean musculoskeletal Tumor Society score was 76%.

CONCLUSION

Despite high failure rates with short revision-free survivals, combined distal femur and proximal tibia reconstruction achieved longtime limb survival in the majority of patients with satisfying function.

Allograft-prosthetic composite versus megaprosthesis in the proximal tibia-What works best?

Modular megaprosthesis (MP) and allograft-prosthetic composite (APC) are the most commonly used reconstructions for large bone defects of the proximal tibia. The primary objective of this study was to compare the two different techniques in terms of failures and functional results. A total of 42 consecutive patients with a mean age of 39.6 years (range 15-81 years) who underwent a reconstruction of the proximal tibia between 2001 and 2012 were included. Twenty-three patients were given an MP, and 19 patients received an APC. There were nine reconstruction failures after an average follow-up of 62 months: five in the MP group and four in the APC group (p=0.957). The 10-year implant survival rate was 78.8% for the MP and 93.7% for the APC (p=0.224). There were no relevant differences between the two groups in functional results. Both MP and APC are valid and satisfactory reconstructive options for massive bone defects in the proximal tibia. In high-demanding patients with no further risk factors, an APC should be considered to provide the best possible functional result for the extensor mechanism.

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

INTRODUCTION

Allograft-prosthesis composite reconstruction after resection of a primary bone tumor may have theoretical advantages, such as restoration of bone stock and soft tissue attachments. However, the reported results of APC of different anatomical sites differ widely. We conducted a meta-analysis to estimate the revision and infection rates associated with allograft-prosthesis composite (APC) reconstructions after resection of a primary bone tumor. We looked for variables, such as anatomic sites and irradiation of the allograft, associated with these outcomes.

MATERIALS AND METHODS

We searched Medline, EMBASE, and Cochrane Library. The primary outcome was the revision rate, and the secondary outcome was the infection rate. Random effects meta-analyses of single proportions were used to estimate pooled rates of events. Meta-regression models were built to assess the effect of moderators on relevant both outcomes.

RESULTS

Thirty-one studies were included: 9 about acetabulum APC, 9 about proximal femur APC, 4 about proximal tibia APC, and 9 about proximal humerus APC. The revision rates ranged from 16 % (95 % CI 10-25 %) for proximal humerus to 38 % (95 % CI 26-52 %) for acetabulum, and were significantly different between anatomic sites (p = 0.028). The infection rates ranged from 8 % (95 % CI 4-16 %) for proximal humerus to 23 % (95 % CI 16-33 %) for proximal tibia and 23 % (95 % CI 15-35 %) acetabulum APCs, and were significantly different between anatomic sites (p = 0.008). Finally, we found that irradiation of the allograft was significantly associated with revision rates (p = 0.033) and infection rates (p < 0.001).

CONCLUSIONS

Results of an APC reconstruction after resection of a primary malignant bone tumor vary significantly between anatomic sites and after irradiation of the allograft.

Distal femur reconstruction with modular tumour prostheses: a single Institution analysis of implant survival comparing fixed versus rotating hinge knee prostheses

PURPOSE

To evaluate the incidence of complications in distal femur reconstructions with modular prostheses, comparing fixed vs rotating hinge knee.

METHODS

Retrospective analysis of implant survival, complications, and functional results of the Rizzoli series on distal femur megaprosthesis. Between 1983 and 2010, 687 distal femur tumour modular prostheses were implanted: 491 fixed hinge and 196 rotating hinge knee prostheses. Failures of the prostheses were classified in five types: type 1, soft tissue failure; type 2, aseptic loosening; type 3, structural failure; type 4, infection; type 5, tumour progression.

RESULTS

Failure rate was 27 % (185/687). Implant survival to all types of failure was 70 % at ten years and 50 % at 20 years with no significant difference between fixed and rotating hinge knee prostheses (p = 0.0928). When excluding type 5 and type 1 failures, the overall survival was 78 % and 58 % at ten and 20 years. There was not a significant difference in implant survival to aseptic loosening (p = 0.5) and infection (p = 0.2) between fixed and rotating hinge knee prostheses. All cases of breakage of prosthetic components occurred in fixed hinge knee prostheses. Functional results, evaluated in 536 pts, were satisfactory in 91.4 % of cases with a mean score of 23.3 with a significantly better function for rotating hinge knee prostheses (p < 0.001).

CONCLUSIONS

The most frequent cause of failure was infection followed by aseptic loosening. Even if better results were expected for rotating hinge knee prostheses, there is no significant difference in overall implant survival. No cases of breakage of prosthetic components occurred in rotating hinge knee prosthesis. Functional results were significantly better for the rotating hinge knee prostheses.

LEVEL OF EVIDENCE

Therapeutic study, level IV (case series).

What was the survival of megaprostheses in lower limb reconstructions after tumor resections?

BACKGROUND

Prosthetic replacement is the most commonly used option for reconstruction of osteoarticular bone loss resulting from bone neoplasm resection or prosthetic failure. Starting in late 2001, we began exclusively using a single system for large-segment osteoarticular reconstruction after tumor resection; to our knowledge, there are no published series from one center evaluating the use of this implant.

QUESTIONS/PURPOSES

We investigated the following issues: (1) What is the overall survival, excluding local tumor recurrence, for these endoprostheses used for tumor reconstructions of the lower extremities (knee and hip)? (2) What types of failure were observed in these reconstructions? (3) Do the survival and complications vary according to site of implant?

METHODS

Between September 2001 and March 2012, we exclusively used this implant for tumor reconstructions. During that time, 278 patients underwent tumor reconstructions of the hip or knee, of whom 200 (72%) were available at a minimum 2 years followup. Seventy-eight patients were excluded from the study for insufficient followup as a result of early death (42) or loss at followup (36). The reconstruction types were the following: proximal femur (69 cases), distal femur (87), proximal tibia (32), and total knee (12). Failures were classified according to the Henderson classification. Nine patients among those with followup shorter than 2 years had presented one or more failures and they were included in our analysis but separately evaluated.

RESULTS

Overall survival (no further surgical procedures of any type after primary surgery), excluding Type 5 failure (tumor recurrence), was 75.9% at 5 years and 66.2% at 10 years. Seventy-one failures occurred in 58 implants (29%). Mechanical failures accounted for 59.2% and nonmechanical failures for 40.8%. The first causes of failure of the implants were the result of soft tissue failure in 6%, aseptic loosening in 3%, structural failure in 7%, infection in 8.5%, and tumor recurrence in 4.5% of the whole series. Nine implants sustained two or more failures. Overall incidence of infection was 9.5%. No statistically significant differences were observed according to anatomical site.

CONCLUSIONS

Like in the case with many such complex oncologic reconstructions, the failure rate at short- to midterm in this group was over 20%. Comparative trials are called for to ascertain whether one implant is superior to another. Infection and structural failure were the most frequent modes of failure in our experience.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Survival of modern knee tumor megaprostheses: failures, functional results, and a comparative statistical analysis

BACKGROUND

Modular megaprostheses are now the most common method of reconstruction after segmental resection of the long bones in the lower extremities. Previous studies reported variable outcome and failure rates after knee megaprosthetic reconstructions.

QUESTIONS/PURPOSES

The objectives of this study were to analyze the results of a modular tumor prosthesis after resection of bone tumor around the knee with respect to (1) survivorship; (2) failure rate; (3) comparative survivorship against different sites of reconstructions and of primary and revision implants; and (4) functional results on the Musculoskeletal Tumor Society (MSTS) scoring system.

METHODS

Between 2003 and 2010, 247 rotating-hinge Global Modular Reconstruction System (GMRS) knee prostheses were implanted in our institute for malignant and aggressive benign tumors. During this time, that group represented 23% of the patients who had oncologic megaprosthesis reconstruction about the knee after resection of primary or metastatic bone tumors (247 of 1086 patients). In the other 77% of cases we used other types of oncologic prostheses. Before 2003 we used the older Howmedica Modular Resection System and Kotz Modular Femur/Tibia Replacement from 2003 we used mostly the GMRS but we continued to use the HMRS in some cases such as patients with poor prognoses, elderly patients, or metastatic patients. Sites included 187 distal femurs and 60 proximal tibias. Causes of megaprosthesis failure were classified according to Henderson et al. in five types: Type 1 (soft tissue failure), Type 2 (aseptic loosening), Type 3 (structural failure), Type 4 (infection), and Type 5 (tumor progression). Followup was at a minimum oncologic followup of 2 years (mean, 4 years; range, 2-8 years). Kaplan-Meier actuarial curves of implant survival to major failures were done. Functional results were analyzed according to the MSTS II system; 223 of the 247 were available for functional scoring (81%).

RESULTS

At latest followup, among 175 treated patients for primary reconstruction, 117 are continuously disease-free, 26 have no evidence of disease after treatment of relapse, eight are alive with disease, and 24 died from disease. The overall failure rate of the megaprostheses in our series was 29.1% (72 of 247). Type 1 failure occurred in 8.5% (21 of 247) cases, Type 2 in 5.6% (14 of 247), Type 3 in 0%, Type 4 in 9.3% (23 of 247), and Type 5 in 5.6% (14 of 247). Kaplan-Meier curve showed an overall implant survival rate for all types of failures of 70% at 4 years and 58% at 8 years. Prosthetic survivorship for revisions was 80% at 5 years and for primary reconstructions was 60% at 5 years (p = 0.013). Survivorship to infection was 95% at 5 years for revision patients and 84% at 5 years for primary patients (p = 0.475). The mean MSTS score was 84 (25.2; range, 8-30) with no difference between sites of localization (24.7 in proximal tibia versus 25.4 in distal femur reconstruction; p = 0.306).

CONCLUSIONS

Results at a minimum of 2 years with this modular prosthesis are satisfactory in terms of survivorship (both oncologic and reconstructive) and causes and rates of failure. Although these results seem comparable with other like implants, we will continue to follow this cohort, and we believe that comparative trials among the available megaprosthesis designs are called for.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Uncemented, custom-made, hydroxyapatite-coated collared distal femoral endoprostheses: up to 18 years' follow-up

We reviewed the outcome of 69 uncemented, custom-made, distal femoral endoprosthetic replacements performed in 69 patients between 1994 and 2006. There were 31 women and 38 men with a mean age at implantation of 16.5 years (5 to 37). All procedures were performed for primary malignant bone tumours of the distal femur. At a mean follow-up of 124.2 months (4 to 212), 53 patients were alive, with one patient lost to follow-up. All nine implants (13.0%) were revised due to aseptic loosening at a mean of 52 months (8 to 91); three implants (4.3%) were revised due to fracture of the shaft of the prosthesis and three patients (4.3%) had a peri-prosthetic fracture. Bone remodelling associated with periosteal cortical thinning adjacent to the uncemented intramedullary stem was seen in 24 patients but this did not predispose to failure. All aseptically loose implants in this series were diagnosed to be loose within the first five years. The results from this study suggest that custom-made uncemented distal femur replacements have a higher rate of aseptic loosening compared to published results for this design when used with cemented fixation. Loosening of uncemented replacements occurs early indicating that initial fixation of the implant is crucial.

Poor prognosis and complications are common in limb salvage surgery for malignant tumors of the proximal tibia invading the fibula

BACKGROUND

Malignant tumors in proximal tibia invading fibula usually have a large tumor volume and are adjacent to the neurovascular bundles. The prognoses and functional outcomes of limb salvage for these patients are uncertain. We, therefore, asked whether patients with limb salvage surgery for malignant tumors in proximal tibia invading fibula had poorer oncological prognosis, higher complication rate, and lower postoperative functional score compared with patients without fibula invasion.

METHODS

We retrospectively reviewed 129 patients with primary malignant tumors in proximal tibia. The patients were divided into two groups, i.e., with and without proximal fibula invasion. A total of 35 and 94 patients were in the group with and without fibula invasion, respectively. Data on demography, operation time, blood loss volume, complications, survival time, and postoperative function were compared between two groups.

RESULTS

The patients with fibula invasion had a longer mean operative time (p = 0.011), less percentage of obtaining wide surgical margin (p = 0.027), lower estimated 5-year survival rate (p = 0.05), higher tumor local recurrence rate (p = 0.042), and earlier postoperative complications (p = 0.01) than the patients without fibula invasion. The difference in postoperative functions as evaluated by the Musculoskeletal Tumor Society functional scoring system was not significant (p = 0.233).

CONCLUSION

Patients with limb salvage surgery for malignant tumors in proximal tibia invading fibula had poorer oncological prognosis, higher complication rate, and acceptable postoperative functions compared with patients without fibula invasion.

Analysis of complications after knee replacement in tumor lesions (20-year experience)

Purpose - retrospective analysis of the causes of complications after knee replacement in tumor lesions depending on the type of implants and classification of complications by severity. Material and methods. The outcomes of operations of knee replacementin tumor lesions performed in 161 patients in the period between 1993 and 2012 were studied. All patients were divided into two groups. The first group included 68 (42.2%) patients, whom the Russian endoprostheses were implanted. The second group included 93 (57.8%) patients, who were operated using modern foreign endoprostheses. Results. 74 (45.9%) patients underwent revision surgery due to the complications in different terms after primary oncologic replacement, with 67 (90.5%) requiring a removal of the primary endoprosthesis. By severity, all complications were divided into 5 types. Infections were the most frequent complications of knee replacement resulting in revision surgery (19 cases, 25.7% of all revision operations). Conclusion. Improvement of oncological systems quality lead to the decrease in the rate of revision surgery due to mechanical reasons. However, the complication rate after knee replacement remains higher than after conventional arthroplasty.

Survival of current production tumor endoprostheses: complications, functional results, and a comparative statistical analysis

BACKGROUND AND OBJECTIVES

Retrospectively analyze outcomes of current-generation Global Modular Replacement System (GMRS) modular tumor endoprosthesis for the lower limb in primary and secondary implantation procedures.

METHODS

Two hundred ninety five prostheses were implanted, 197 were primary implants, 98 were for revision surgery; revision procedures included 84 failed tumor reconstructions and 14 failed non-tumor reconstructions. Anatomic sites included: distal femur 199; proximal tibia 60; proximal femur 32;total femur 4. Endoprosthesis failures were classified as soft-tissue failures (Type 1), aseptic loosening (Type 2), structural fracture (Type 3), infection (Type 4), and tumor recurrence (Type 5). MSTS functional scores were measured.

RESULTS

The overall failure rate was 28.8% and failure occurred at a median of 1.7 years (range, 1 month to 7 years). At a mean oncologic follow up of 4.2 years (range, 2-8 years), 195 patients are continuously NED, 43 NED after treatment of relapse, 10 AWD, 33 DWD. There was a significant difference in implant survival of all modes of failure between primary and revision implants (P = 0.03). No prosthetic fracture occurred. The average functional score was 81.6% (24.5).

CONCLUSIONS

Mid-term results with GMRS are promising, with good functional results and low incidence of complications for primary implants.

LEVEL OF EVIDENCE

Therapeutic study, level IV-1 (case series).

Long term results of fixed-hinge megaprostheses in limb salvage for malignancy

We retrospectively studied the files of 669 patients with musculoskeletal tumors treated with limb salvage and reconstruction using fixed-hinge knee megaprostheses. We used the KMFTR® prosthesis from 1983 to 1989 in 126 patients, and the HMRS® prosthesis thereafter in 543 patients because of the anatomical femoral stem with one lateral flange for improved stress-shielding, the new hinge design and new generation polyethylene placed centrally in the metallic hinge, and the improved function compared to the former prosthesis. Distal femoral reconstructions were done in 474, proximal tibia in 163, extrarticular knee joint in nine, and total femoral in 23 patients. At 10 and 20 years follow-up, survival to breakage was 95% and 85%, to aseptic loosening 94% and 82%, to infection 90% and 82%, and to polyethylene wear 95% and 37%. A statistically significant higher survival to breakage of the HMRS® prostheses was observed. No statistical difference of survival to breakage regarding the site of reconstruction, aseptic loosening, infection, polyethylene wear and mean functional score between the two types of prostheses was observed.

A comparison of tumor prosthesis implantation and pasteurized autograft-prosthesis composite for proximal tibial tumor

BACKGROUND AND OBJECTIVES

Although previous reports on composite biologic reconstruction in the proximal tibial location vary, we hypothesized that this type of reconstruction may reduce the late infection rate and have advantages in terms of longevity by restoring bone stock.

METHODS

Primary analysis addressed differences between 62 tumor prosthesis (TP) and 25 pasteurized autograft-prosthesis composite (PPC) reconstructions in terms of survival rates, functional outcomes, and temporal patterns of infection.

RESULTS

The 10-year survival rates of the TP and PPC groups were 73.9 ± 11.7 and 68.7 ± 20.1 %, respectively (P = 0.64). Reconstructive failure occurred in 16 (25.8 %) in the TP and in 7 (28 %) in the PPC group. The cause of failures in the TP group was infection (16), whereas those of PPC group were infection (5), loosening (1), and local recurrence (1). The mean functional scores of TP (52) and PPC (20) patients that maintained a mobile joint were 24.2 (81 %) and 25.1 (83.6 %), respectively. Infection rates in the two groups were similar (P = 0.328), but infections occurred earlier in the PPC group (P = 0.011).

CONCLUSIONS

This comparative study suggests composite biological reconstruction shows a comparable long-term survival rate to TP reconstruction; however, the composite method has a tendency to a lower rate of late infection.

Cause of infection in proximal tibial endoprosthetic reconstructions

INTRODUCTION

The underlying cause of proximal tibial prosthetic failure by infection is unclear. We asked: (1) Is resection amount related to prosthetic infection? (2) What other risk factors are related with infection? (3) What are the survivorship and functional outcomes of proximal tibial endoprosthetic reconstruction?

METHODS

Sixty-two patients who underwent modular proximal tibial megaprosthesis reconstruction were analyzed. Follow-up duration averaged 98 months (range 26-240 months). Associations between prognostic variables and prosthesis survival were assessed.

RESULTS

The 10-year prosthetic survival of the 62 implants was 73.9 ± 11.7%. Prostheses were removed in 16 (25.8%) patients for infection and 3 of the 16 underwent amputation. Resection of >37% (P = 0.016) of the tibia was found to be related to infection. Application of chemotherapy (P = 0.912) and use of synthetic material to fix the patella tendon (P = 0.2) were not found to influence prosthetic survival. Functional outcomes (determined by the MSTS system) of the 52 patients that maintained a mobile joint averaged 24.2 (81%) (range 18-28).

CONCLUSIONS

Our study suggests that the amount of bone resection is related with prosthetic failure by infection, however, the contribution of other risk factors should not be underestimated.

A biomechanical evaluation of press-fit stem constructs for tumor endoprosthetic reconstruction of the distal femur

This study was designed to assess the biomechanical parameters of the older Kotz Modular Femur Tibia Reconstruction (Stryker Inc, Mahwah, NJ) stem and the newer Restoration and the unfluted Global Modular Replacement System (Stryker Inc, Mahwah, NJ) uncemented stems for use with tumor endoprostheses as well as to assess the optimal reaming technique for insertion of these stems. Fresh-frozen adult femora or composite distal femora were implanted with the uncemented stems. Separate experiments were performed to compare reaming technique and bone resection level. All constructs were mechanically tested for axial compression, lateral bending, and torsional stiffness and torque to failure. Results showed that the biomechanical performance of all the stems were similar with respect to each parameter. Cylindrical reaming was associated with a significantly higher torque to failure than flexible reaming in the diaphysis (P = .006). Newer uncemented stems provide adequate initial biomechanical stability for implantation in the distal femur.

Advances in segmental endoprosthetic reconstruction for extremity tumors: a review of contemporary designs and techniques

BACKGROUND

Improved understanding and advances in treatment regimens have led to increased longevity among patients diagnosed with extremity soft tissue sarcomas. Limb salvage techniques and implants have improved and continue to evolve to accommodate the increasing demands and survival of these patients.

METHODS

The current report is a review of the literature for recent advancements in techniques, implant design, and outcomes in the field of limb salvage therapy using segmental megaprostheses for the treatment of extremity sarcomas. We report on our experience in this field utilizing a classification system of failure mechanisms to outline to discuss current controversies in management.

RESULTS

Five mechanisms of failure have been identified: soft-tissue failure, aseptic loosening, structural failure, infection, and tumor progression. Infection was the most common mode of failure in our series, accounting for 34% of cases. Soft-tissue failure occurred most commonly in the joints that depend heavily on periarticular muscles and ligaments for stability due to their high degree of functional range of motion. We observed a 28% soft-tissue failure rate about the shoulder and hip, aseptic loosening accounted for 19% of implant failures, and structural failure was seen in 17% of cases. Seventeen percent of cases failed due to tumor progression, an etiology that is defined by biological factors, surgical technique, and adjuvant therapies.

CONCLUSIONS

Surgical techniques and megaprosthesis designs are constantly changing in order to meet the challenge of increasing functional demands and longevity in this unique patient population. A classification system defined by treatment failure etiologies provides the framework for discussion of current controversies in limb salvage therapy as well as a guide for advancement and potential solutions in this challenging arena.

Surgical technique: extraarticular knee resection with prosthesis-proximal tibia-extensor apparatus allograft for tumors invading the knee

BACKGROUND

Intraarticular extension of a tumor requires a conventional extraarticular resection with en bloc removal of the entire knee, including extensor apparatus. Knee arthrodesis usually has been performed as a reconstruction. To avoid the functional loss derived from the resection of the extensor apparatus, a modified technique, saving the continuity of the extensor apparatus, has been proposed, but at the expense of achieving wide margins. In tumors involving the joint cavity, the entire joint complex including the distal femur, proximal tibia, the full extensor apparatus, and the whole inviolated joint capsule must be excised. We propose a novel reconstructive technique to restore knee function after a true extrarticular resection.

DESCRIPTION OF TECHNIQUE

The approach involves a true en bloc extraarticular resection of the whole knee, including the entire extensor apparatus. We performed the reconstruction with a femoral megaprosthesis combined with a tibial allograft-prosthetic composite with its whole extensor apparatus (quadriceps tendon, patella, patellar tendon, and proximal tibia below the anterior tuberosity).

PATIENTS AND METHODS

We retrospectively reviewed 14 patients (seven with bone and seven with soft tissue tumors) who underwent this procedure from 1996 to 2009. Clinical and radiographic evaluations were performed using the MSTS-ISOLS functional evaluation system. The minimum followup was 1 year (average, 4.5 years; range, 1-12 years).

RESULTS

We achieved wide margins in 13 patients (two contaminated), and marginal in one. There were three local recurrences, all in the patients with marginal or contaminated resections. Active knee extension was obtained in all patients, with an extensor lag of 0° to 15° in primary procedures. MSTS-ISOLS scores ranged from 67% to 90%. No patients had neurovascular complications; two patients had deep infections.

CONCLUSIONS

Combining a true knee extraarticular resection with an allograft-prosthetic composite including the whole extensor apparatus generally allows wide resection margins while providing a mobile knee with good extension in patients traditionally needing a knee arthrodesis.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Failure mode classification for tumor endoprostheses: retrospective review of five institutions and a literature review

BACKGROUND

Massive endoprostheses provide orthopaedic oncologists with many reconstructive options after tumor resection, although failure rates are high. Because the number of these procedures is limited, failure of these devices has not been studied or classified adequately. This investigation is a multicenter review of the use of segmental endoprostheses with a focus on the modes, frequency, and timing of failure.

METHODS

Retrospective reviews of the operative databases of five institutions identified 2174 skeletally mature patients who received a large endoprosthesis for tumor resection. Patients who had failure of the endoprosthesis were identified, and the etiology and timing of failure were noted. Similar failures were tabulated and classified on the basis of the risk of amputation and urgency of treatment. Statistical analysis was performed to identify dependent relationships among mode of failure, anatomic location, and failure timing. A literature review was performed, and similar analyses were done for these data.

RESULTS

Five hundred and thirty-four failures were identified. Five modes of failure were identified and classified: soft-tissue failures (Type 1), aseptic loosening (Type 2), structural failures (Type 3), infection (Type 4), and tumor progression (Type 5). The most common mode of failure in this series was infection; in the literature, it was aseptic loosening. Statistical dependence was found between anatomic location and mode of failure and between mode of failure and time to failure. Significant differences were found in the incidence of failure mode Types 1, 2, 3, and 4 when polyaxial and uniaxial joints were compared. Significant dependence was also found between failure mode and anatomic location in the literature data.

CONCLUSIONS

There are five primary modes of endoprosthetic failure, and their relative incidences are significantly different and dependent on anatomic location. Mode of failure and time to failure also show a significant dependence. Because of these relationships, cumulative reporting of segmental failures should be avoided because anatomy-specific trends will be missed. Endoprosthetic design improvements should address failure modes specific to the anatomic location.

Cemented endoprosthetic reconstruction of the proximal tibia: how long do they last?

BACKGROUND

The few available studies documenting the long-term survival of cemented proximal tibial endoprostheses for musculoskeletal tumors do not differentiate between stem designs or patient diagnosis. There is wide variation in survival rates reported, possibly a result of this heterogeneity in patient population and implant design.

QUESTIONS/PURPOSES

We therefore asked: (1) How long do proximal tibial endoprostheses last? (2) What is the typical long-term functional result after proximal tibial replacement? And (3) what are the short- and long-term complications associated with endoprosthetic reconstruction of the proximal tibia, particularly with respect to the soft tissue reconstruction?

PATIENTS AND METHODS

We retrospectively reviewed 52 patients with 52 proximal tibial endoprosthetic reconstructions for a tumor-related diagnosis. Kaplan-Meier survivorship analysis was performed using revision of the stemmed components for any reason as an endpoint for implants, and death due to disease progression for patients. Function was assessed using the MSTS scoring system. The minimum followup was 1 month (mean, 96 months: range, 1-284 months; median, 69 months).

RESULTS

Using revision of the stemmed components for any reason as an end point, overall prosthesis survival at 5, 10, 15, and 20 years was 94%, 86%, 66%, and 37%, respectively. The 29 modular implants demonstrated a trend toward improved survival compared to the 23 custom-designed components, with a 15-year survivorship of 88% versus 63%. The mean postoperative Musculoskeletal Tumor Society score at most recent followup was 82% of normal function (mean raw score, 24.6; range, 4-29).

CONCLUSIONS

Cemented endoprosthetic reconstruction of the proximal tibia provides a reliable method of reconstruction following tumor resection.

Revision of broken knee megaprostheses: new solution to old problems

BACKGROUND

Low-cost indigenous megaprostheses used in the developing world are prone to mechanical failure but the frequency and causes are not well established.

QUESTIONS/PURPOSES

We retrospectively analyzed the causes of failure, particularly design, and suggest changes to reduce the breakage. We also report our experience with revision surgery.

METHODS

We identified 28 breakages in 266 megaprosthetic knee arthroplasties performed between January 2000 and December 2006. Twenty-six breakages were revised to another prosthesis. The complications were studied and the function was evaluated. Prostheses were studied for failure by the computer-aided design program SolidWorks(®) and Hyperworks(®) for finite element analysis (FEA). Design improvements were performed based on these results.

RESULTS

In 21 cases, the failure occurred at the stem-collar junction, the point of maximum stress predicted by FEA. Stainless steel implants were prone to failure. There was one early and one late infection. Three patients died of metastatic disease. The most difficult surgical step involved the removal of the well-cemented broken stem from the intramedullary canal. Musculoskeletal Tumor Society scores varied from 27 to 29 after revision. FEA revealed stress could be reduced by filleting the stem-collar junction and by two-piece stems.

CONCLUSIONS

Revisions of broken total knee megaprostheses, though technically difficult, have allowed patients reasonable function. We recommend design analysis for custom prostheses to point to areas of weakness. Breakages can be reduced by using titanium stems and filleting the junction or by having two-piece inserted stems. Incorporating these changes has reduced the failures in our experience.

Resection and arthrodesis of the knee joint for giant cell tumours of bone

PURPOSE

To evaluate functional outcomes and complications following resection and arthrodesis of the knee for giant cell tumours (GCTs) of bone, in comparison to treatment by endoprosthetic replacements reported elsewhere.

METHODS

18 men and 14 women aged 18 to 40 (mean, 28) years underwent resection and arthrodesis of the knee for GCTs of bone involving the distal femur (n=17) and proximal tibia (n=15). After wide resection, 2 struts were fashioned from the harvested fibula/ fibulae and inserted into the medullary canal at the resected ends of the tibia and femur. The corresponding ends of the struts were inserted into peg holes made in the unaffected condyles in a divergent fashion. The knee was arthrodesed in 5 to 10 degrees of flexion, with the limb kept 1 cm short. A 95-degree AO condylar bladeplate (10-12 holes) was fixed at the resected ends, with a minimum of 8 cortices purchase. Cancellous bone grafts were placed transversely along the struts and circumferentially over the host-graft junctions. Outcomes and complications were evaluated and compared with those of endoprosthetic arthroplasty reported elsewhere.

RESULTS

Patients were followed up for a mean of 8 (range, 3-12) years. The mean size of the tumours was 10x8x6 cm. All patients achieved arthrodesis and full weight bearing without pain within 6 to 10 (mean, 6) months. No shortening, loss of alignment, loosening, implant breakage ensued. One patient had a deep infection and absorption at the host-graft junction. Another had a stress fracture of the fibular strut after plate removal. Two patients had a transient peroneal nerve palsy. One patient had local recurrence and extensive fungation and underwent amputation. The mean functional score was 26 (87% of the full score), compared to 66 to 85% in endoprosthetic arthroplasty reported elsewhere.

CONCLUSION

Arthrodesis is a viable alternative to customised arthroplasty and provides a long-lasting and cost-effective reconstruction for average patients in developing countries.

Compressive osseointegration of tibial implants in primary cancer reconstruction

Compressive osseointegration technology, which provides immediate, mechanically compliant endoprosthetic fixation, has been adapted for massive proximal tibial reconstructions in an attempt to avoid aseptic failure encountered with conventional stems. A retrospective review of 16 patients with resected tumors was undertaken to determine whether compressive osseointegration can provide durable anchorage of tibial implants. Medical records, radiographs, and clinical examinations were reviewed to assess surgical, local disease control, and prosthetic outcomes. The average age was 18 years (range, 12-42 years). Diagnoses included osteosarcoma (12), Ewing sarcoma (two), chondrosarcoma (one), and undifferentiated sarcoma (one). Minimum followup was 2 years (mean, 4.5 years; range, 2-10.3 years); no patient was lost to followup. There were no local recurrences. Four patients developed metastatic disease; one patient died of his primary tumor, and another died from a chemotherapy-related malignancy. Complications included one early deep infection that ultimately resulted in prosthetic loosening and the need for an above-knee amputation. There were two late deep infections; prosthetic retention was achieved with débridement and antibiotics. One patient developed aseptic loosening and underwent revision; the other 15 implants provided stable osseointegration at last followup. Compressive osseointegration technology can thus achieve acceptable short-term endoprosthetic fixation results and may reduce the risk of aseptic loosening reported with conventional tibial stems.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Early equivalence of uncemented press-fit and Compress femoral fixation

Bone ingrowth promises more durable biologic fixation of megaprostheses. The relative performance of different types of fixation is unknown. We compared the fixation of two forms of biologically fixed femoral components: an intramedullary uncemented press-fit stem (UCS; Group 1, 50 patients) and a Compress((R)) uncemented fixation (CPS; Group 2, 41 patients). In Group 1, the overall Kaplan-Meier prosthetic survival rates were 85% at 5 and 71% at 10 years. Most failures were long-term developments. Aseptic loosening was the primary cause of failure. Stem diameters less than 13.5 mm and a diaphyseal/stem coefficient greater than 2.5 mm were associated with decreased prosthetic survival. In Group 2, the overall rate of CPS survival was 88% at 5 years. Failure of femoral fixation or fracture during the first year was the main reason for revision. Five-year survival rates were similar between the groups and we observed no difference in the functional success of the implants. We found no failures after 1-year followup in Group 2 (CPS). Any difference in prosthetic survival can only be proven by longer-term study or a randomized trial.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.