A rotating-hinge knee replacement for malignant tumors of the femur and tibia

Failure of the Yoke With a Rotating-Hinge Total Knee Arthroplasty: A Case Report

CASE

A patient underwent revision of a total knee replacement to a cementless rotating-hinge prosthesis. The femoral component became loose, but due to the patient's frailty and cognitive decline, revision was not performed. Subsequently, the yoke failed, dissociating the femoral and tibial components, necessitating a single-stage revision.

CONCLUSION

This case underlines the need for robust fixation of components of rotating-hinge knee replacements to avoid mechanical failures. It contributes valuable insights to the limited literature on yoke failure in total knee arthroplasty, emphasizing the importance of implant design, patient selection, and surgical technique to prevent such complications.

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.

Intermediate-term results and risk factors analysis of tumor endoprosthesis in paediatric patients after the resection of lower extremity bone sarcoma

BACKGROUND

Mechanical failure of the endoprostheses is a concern in paediatric patients with primary bone sarcoma. Their long-term results are variable in the Asian population, thus we aim to investigate the outcome by assessing the mechanical failure, its risk factors and the functional results.

METHODS

We retrospectively reviewed 38 paediatric patients (mean 13.29, range 6-18) with primary bone sarcoma of lower extremity undergone chemotherapy and limb salvage surgery with tumor endoprosthesis between 2003 and 2016. All hospital notes were reviewed for any type of failures. Risk factors for implant loosening like stem size, remaining bone length, stem length, extracortical bone bridge ingrowth (EBBI), the ratio of resected bone length to whole bone length, bone stem ratio and custom-made versus modular were analyzed. The limb function was recorded by Musculoskeletal Tumor Society (MSTS) score. Median follow-up time was 7.42 years (3.0-15.4 years) and minimum follow-up for surviving patients was 2 years.

RESULTS

Endoprosthesis survivorship, according to Kaplan Meier was 94.7%, 85.4% and 66.2% at 2, 5 and 10 years respectively. Type II failure occurred in three patients (7.9%). Type III failure occurred in four patients (10.5%). Type IV failure occured in two patients (5.2%). Only EBBI independently predicted implant loosening (p = .007). Risk factors like stem size, remaining bone length, stem length, the ratio of resected bone length to whole bone length and custom-made versus modular were not associated with increase in implant loosening (p > .05). The mean stem size was 9.41 mm in asymptomatic group, comparable with 9.22 mm in the failure group (p = .79). The MSTS score was 29.62.

CONCLUSIONS

Our data suggests that paediatric Chinese patients with small body built had good and excellent mid-term results in implant survival and limb function respectively. EBBI is important in preventing loosening in tumor endoprosthesis. In contrast to the reported higher failure risk with stem size <12 mm, we found no increased loosening rate with smaller stem size endoprosthesis.

LEVEL OF EVIDENCE

Class III.

Patella cryo-free technique with recycled frozen autograft reconstruction preserves extensor mechanism for proximal tibial malignancy

BACKGROUNDS

We designed a patella cryo-free method to protect patella from cryoinjury during recycled frozen bone-prosthesis-composite reconstruction for proximal tibial malignancy. This study aimed to use animal model to ensure safety and efficacy of this method and reported our clinical outcomes.

METHODS

Six swine proximal tibias along with patella and patellar tendon were harvested and dived into group A (n = 3, traditional patella freezing) and group B (n = 3, patella cryo-free). Temperature curve measurement, histological analysis, and TUNEL assay were performed in both groups. Clinically, we retrospectively reviewed 23 patients with proximal tibia malignant bone tumor (13: traditional patella freezing method; 10: patella cryo-free method). The clinical and functional outcomes were reported and compared in both groups.

RESULTS

Temperature curve of the group B showed that ideal therapeutic temperature (<-60°C) required to kill tumor cells can be achieved in the proximal tibia while the innocent patella can be kept in room temperature at all time. Histological analysis showed better preservation of the cartilage tissue in patella of group B. TUNEL assay showed significantly more apoptotic cells in the frozen tibia of both groups and frozen patella of group A. When reviewing our clinical results, less complication of the patella as well as better functional preservation were found in patients subjecting to patella cryo-free method. No local recurrence was observed in either group.

CONCLUSION

Patellar cryo-free technique could protect patella from cryoinjury during freezing and therefore preserve more extensor functions for patients with proximal tibial malignant bone tumors.

Revision surgeries for tumor endoprostheses around the knee joint: a mid-long-term follow-up of 20 cases

Background

Tumor endoprostheses of the knee joint after limb salvage surgery is associated with high rates of complications, which has introduced great challenges to a delayed revision surgery. The aim of the study was to summarize the failures, functional outcomes and prosthetic survival in revision tumor endoprostheses of the knee joint.

Methods

The clinical data of 20 patients with malignant tumors who received prosthetic revisions after limb salvage surgery from January, 2000 until January, 2018 were retrospectively reviewed. The cohort was constituted of 11 male and 9 female patients with a mean age of 34.1 years (range, 16 to 66 years). Infection cases received two-stage revisions after removing prostheses initially, while all other cases received one-stage revisions. Revision reasons and complications were well documented and analyzed.

Results

All patients received complete follow-up with a mean time of 64.7 months (range, 27 to 155 months). A total of 6 (6/20, 30.0%) patients experienced a second complication after revision surgery, of whom, one patient with deep infection experienced repeated infections after prosthetic revision and received amputation surgery; one patient revised of prosthetic fracture experienced an infection and received a second-stage infection revision; one case revised of prosthetic loosening had deep infection receiving anti-infective therapy with prostheses still in position; one case having wound complication healed after receiving two times of debridement surgery; one MBGCT patient experienced a second aseptic loosening 6 years after the initial loosening thus undergoing a second revision; a recurrent osteosarcoma patient died of pulmonary metastasis 3 years after revision surgery. Kaplan-Meier survival curve indicated a 5-year survival rate of initial prostheses was 75%. The Musculoskeletal Tumor Society (MSTS-93) score [20.9 (range, 15 to 27 scores)] at 1 year after revision surgeries was significantly improved (p < 0.001) when compared with the score [17.2 (range, 13 to 21 scores)] before revisions.

Conclusion

Prosthetic mechanical problems, aseptic loosening and infections were primary reasons for revisions after tumor endoprostheses of the knee joint. Although revision surgeries were complicated while still associated with high risk of failure, which remains the remedy strategy for limb salvage and functional recovery in those patients.

Rotating Hinge Knee Arthroplasty for Revision Prosthetic-Knee Infection: Good Functional Outcomes but a Crucial Need for Superinfection Prevention

Introduction: Management of chronic infection following total knee arthroplasty (TKA) is challenging. Rotating hinged prostheses are often required in this setting due to severe bone loss, ligamentous insufficiency, or a combination of the two. The nature of the mechanical and septic complications occurring in this setting has not been well-described. The aim of this study was to evaluate patient outcomes using a hinge knee prosthesis for prosthetic knee infections and to investigate risk factors for implant removal. Methods: This was a retrospective cohort study that included all patients treated in our tertiary level referral center between January 2009 and December 2016 for prosthetic knee infection with a hinge knee prosthesis. Only patients with a minimum 2-year of follow-up were included. Functional evaluation was performed using international knee society (IKS) "Knee" and "Function" scores. Survival analysis comparing implant removal risks for mechanical and septic causes was performed using Cox univariate analysis and Kaplan-Meier curves. Risk factors for implant removal and septic failure were assessed. Results: Forty-six knees were eligible for inclusion. The majority of patients had satisfactory functional outcomes as determined by mean IKS scores (mean knee score: 70.53, mean function score: 46.53 points, and mean knee flexion: 88.75°). The 2-year implant survival rate was 89% but dropped to 65% at 7 years follow-up. The risk of failure (i.e., implant removal) was higher for septic etiology compared to mechanical causes. Patients with American society of anesthesiologists (ASA) score>1, immunosuppression, or with peripheral arterial diseases had a higher risk for septic failure. Patients with acute infection according to the Tsukayamaclassification had a higher risk of failure. Of the 46 patients included, 19 (41.3%) had atleast one infectious event on the surgical knee and most of these were superinfections (14/19) with new pathogens isolated. Among pathogens responsible for superinfections (i) cefazolin and gentamicin were both active in six of the cases but failed to prevent the superinfection; (ii) cefazolin and/or gentamicin were not active in eight patients, leading to alternative systemic and/or local antimicrobial prophylaxis consideration. Conclusions: Patients with chronic total knee arthroplasty (TKA) infection, requiring revision using rotating hinge implant, had good functional outcomes but experienced a high rate of septic failure, mostly due to bacterial superinfection. These patients may need optimal antimicrobial systemic prophylaxis and innovative approaches to reduce the rate of superinfection.

Revision Total Knee Arthroplasty Using an Uncemented Metaphyseal Sleeve, Rotating Hinge Prosthesis: A Case Series of 99 Patients

BACKGROUND

Hinge knee replacement is a salvage procedure with historically high failure and complication rates. We aim to analyze the use of an uncemented metaphyseal sleeve revision knee replacement in our unit-a third-generation rotating hinge knee prosthesis. This is the largest reported series of this implant with longest follow up.

METHODS

We retrospectively identified 99 revision cases performed (2002-2018). In total, 67 of 99 (68%) cases were performed for aseptic etiology, whereas 32 of 99 (32%) cases were performed for infection. Clinical outcomes were assessed using the Oxford Knee Score, survivorship analysis, and incidence of revision/reoperations. Mean follow-up was 7 years (range 1.5-18).

RESULTS

At follow-up, the mean Oxford Knee Score had improved from 10 points to 25 points. At mean 7 years of follow up, 18 of 99 cases had undergone revision giving a survivorship of 81% (90% aseptic). In total, 10 of 18 cases were performed for infection (10%) and 9 of 18 cases were performed for aseptic reasons (9%), of which 5 were for patella resurfacing (2 revision), 2 for failure of bony ingrowth, and 1 for fracture. Twenty-six patients (26%) had complications postoperatively, with patella disorders and reduced range of movement the most common. Patients who did not undergo patella resurfacing were significantly more likely to need revision of any cause (P = .01).

CONCLUSION

This is the largest study of this prosthesis with longest follow-up. It demonstrates good survivorship and improvement in knee pain. Those with infection are at greatest risk of revision. Significant numbers have patella dysfunction/anterior knee symptoms therefore patella resurfacing should be considered when using this implant.

LEVEL OF EVIDENCE

IV.

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.

Indications, Survivorship, and Clinical Outcomes of a Rotating Hinge Total Knee and Distal Femoral Arthroplasty System

BACKGROUND

Rotating hinge knee prostheses (with or without distal femoral replacement) are indicated in cases of unreconstructible bony or soft tissue compromise. Despite their versatility, these implants have demonstrated high rates of mechanical failure. We aimed to review clinical outcomes of a novel hinged knee arthroplasty system.

METHODS

We reviewed all cases in a prospective database of hinged total knee arthroplasty (with and without distal femoral arthroplasty) involving a single manufacturer's implant system at a large tertiary-level academic health sciences center. We collected reasons for surgery, implant survivorship, reasons for revision, and clinical outcomes (Short Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores).

RESULTS

Seventy-six cases of hinged knee implants using the knee system under investigation were performed (39 hinged total knee and 37 distal femoral replacements) between 2011 and 2018, inclusive. Indications for surgery varied, with second-stage reimplantation most common for rotating hinge and fracture most common for distal femoral arthroplasty. There were 6 revisions in the rotating hinge group (none for aseptic loosening) and 5 in the distal femoral arthroplasty group (1 for aseptic loosening). Average follow-up was 2.89 ± 2.09 years. Postoperative Short Form 12 (Physical Component), Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores were 30.12 ± 10.17, 55.90 ± 21.51, and 115.62 ± 45.20, respectively.

CONCLUSION

This novel hinged knee system is a highly durable option for complex and revision knee arthroplasty. Early failures tend to be secondary to infection. We observed only a single case of aseptic loosening. Although these early results are encouraging, ongoing follow-up is required to determine long-term prognosis in patients receiving this implant.

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.

Proximal tibial replacement in revision knee arthroplasty for non-oncologic indications

Proximal tibial metaphyseal bone loss compromises the alignment and fixation of components during revision total knee arthroplasty. In massive, segmental defects with loss of collateral ligamentous support and lack of bone to support the use of prosthetic augments or metaphyseal cones or sleeves, a hinged proximal tibial replacement or a so-called “megaprosthesis” should be available. While proximal tibial replacement is the reconstructive method of choice in the setting of bone tumor resection, applications in non-oncologic joint arthroplasty are rare and may offer an opportunity for limb salvage in dire clinical scenarios with massive proximal tibial bone loss. This report reviews 6 cases of proximal tibial replacement.

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.

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.

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 Innovation in Sarcoma Surgery

The field of orthopaedic oncology relies on innovative techniques to resect and reconstruct a bone or soft tissue tumour. This article reviews some of the most recent and important innovations in the field, including biological and implant reconstructions, together with computer-assisted surgery. It also looks at innovations in other fields of oncology to assess the impact and change that has been required by surgeons; topics including surgical margins, preoperative radiotherapy and future advances are discussed.

Limb-salvage treatment of en-block resected distal femoral tumors with endoprosthesis of all-polyethylene tibial component: a 9-year follow-up study

OBJECTIVE

To evaluate the medium-term outcome of limb-salvage surgery using all-polyethylene tibial endoprosthetic replacement following en-block resection for distal femoral tumors.

METHODS

Forty-nine patients with distal femoral tumor were treated between June 2006 and June 2012. The follow-up period was 6-110 months (average 53.4 months). The prosthetic survival was analyzed using the Kaplan-Meier method. The classification of failure of limb salvage after reconstructive surgery for bone tumors was adapted. Limb function was evaluated with the scoring system of the Musculoskeletal Tumor Society (MSTS).

RESULTS

Complications were observed in six cases (12.2%). Four suffered infection around the prosthesis, of which two cases were treated with debridement, drainage, and antibiotics without removal of the prosthesis, and the other two cases underwent amputation. Two cases were identified as radiographically loose at 7 year follow-up and did not require revision surgery. One patient underwent amputation due to local recurrence. Failure of limb salvage occurred in nine cases (18.4%), of which two cases were of type 1A, two cases of type 2B, three cases of type 4A, one case of type 4B, and one case of type 5A. The mean MSTS score was 84.3%. Twelve cases died due to distant metastases (24.5%), and the average survival time for these patients was 13.5 months. Thirty-seven patients survived (75.5%), for whom the average follow-up time was 66.3 months and the 5-year prosthetic survival rate was 88.2%.

CONCLUSION

The outcome of medium-term and long-term clinical follow-up was satisfactory. All-polyethylene tibial endoprosthetic replacement following en-block resection can be an alternative method of limb salvage for distal femoral tumors.

Comparison of gait parameters in distal femoral replacement using a metallic endoprosthesis versus allograft reconstruction

BACKGROUND/AIM

Restoration of gait mechanics after reconstruction have been associated with improved functional outcomes and increased longevity of the reconstruction. The goal of this study is to compare the gait mechanics of an allograft reconstruction of the distal femur to both metallic endoprosthetic reconstruction relative to normal control subjects.

METHODS

Gait parameters were captured using motion capture system, and then analyzed and compared for patients with metallic endoprosthetic reconstructions, and patients with allograft reconstructions of the distal femur following resection of malignant bone tumor, with subjects having no history of musculoskeletal disorders serving as a control group.

RESULTS

All reconstructed distal femurs following tumor resection resulted in decreased range of motion reflected in observed flexion/extension angles compared to the normal limbs. The allograft reconstructed knees demonstrated normal patterns of rotation whereas the metal subjects had abnormal patterns of rotation and statistically significant differences in rotational moments.

CONCLUSION

Allograft distal femoral reconstruction after malignant excision remains a viable option for surgeons faced with problems associated with iatrogenic muscle, bone and soft tissue defects.

Intermediate-Term Results of 142 Single-Design, Rotating-Hinge Implants: Frequent Complications May Not Preclude Salvage of Severely Affected Knees

Rotating-hinge knee prostheses have low survivorship and high complications except in primary arthroplasties in elderly patients. We retrospectively reviewed 142 single third-generation design, rotating hinge prostheses (11 primary procedures and 131 revisions) at 57 months follow up. Implant survival was 73%. Successful two-stage reimplantation for prosthetic infection was 78.4% but new infection rate was 22%. The tibial component was durable while the femoral component was problematic. We observed only one patellar maltracking and no polyethylene wear. A third generation rotating-hinge arthroplasty reconstruction was reliable in complex problems. Outcomes in primary situations were excellent. Complications were the rule rather than the exception in revisions. With timely intervention, attention to soft tissue coverage, and realistic expectations, complications were contained and functional benefits were appreciable.

Bone-prosthesis composite with rotating hinged-knee prosthesis in limb salvage surgery for high-grade sarcoma around the knee

Bone prosthesis composite (BPC) had been widely-used in reconstruction after wide excision of malignant tumors around the knee. However, implant selection for BPC remains a dilemma. Forty-one patients with high-grade malignant bone tumors around the knee who underwent excision and reconstruction with BPC and rotating hinged knee (RHK) prosthesis were included. The mean follow-up time was 54 months (range, 31-78 months). The average Musculoskeletal Tumor Society Rating score was 93.4% (range, 73-100%). The mean range of motion was 125°. Complications included 2 local recurrences, 2 nonunions, and 1 peri-prosthetic fracture. The reconstruction with BPC using the RHK prosthesis provided consistently good functional results with a low complication rate. The RHK prosthesis is a promising choice for BPC reconstruction.

Mid-term survival following primary hinged total knee replacement is good irrespective of the indication for surgery

PURPOSE

The use of 'hinged' knee prostheses for primary knee arthroplasty procedures is increasing. This analysis reports the rates of implant survival, modes of failure, revision details and functional outcomes with particular reference to the primary indication for surgery for a cohort of patients treated with primary hinged knee replacement.

METHODS

Systematic review with supplementary analysis using data from the National Joint Registry and Department of Health. Analysis included 964 patients undergoing primary hinged knee replacement between April 2003 and December 2010. Survival at a maximum of 7 years was calculated for the group as a whole and dependent upon the indication for surgery (osteoarthritis vs. rheumatoid/inflammatory arthritis vs. post-traumatic arthritis). Functional outcomes (pre- and post-operative Oxford Knee and Euroqol-5D scores and post-operative satisfaction) were available for 46 patients.

RESULTS

In total, 20 cases required revision. The 5-year survival rate (96.8% [95% CI 95.1-98.4%]) was not dependent upon the primary surgical indication (p = n.s.). The commonest reasons for revision were infection (8 cases), peri-prosthetic fracture (4 cases) and aseptic loosening (3 cases). Patients reported substantial improvements in their Oxford Knee Score (mean improvement = 17.6, [95% CI 14.4-20.8]) and EQ5D index (mean improvement = 0.357, [95% CI 0.248-0.467]). Levels of post-operative satisfaction were high.

CONCLUSIONS

Hinged knee replacement can be considered as a viable alternative to more traditional unconstrained designs in the complex primary setting. These findings are clinically relevant as they support the increasing use of hinged knee replacements for the arthritic knee in which there is concomitant severe bone loss, deformity or instability. Surgeons using these implants can have confidence that their mid-term performance is comparable to more conventional knee designs.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Posterior dislocation of the hinge-post extension in a rotating hinge total knee prosthesis

The rotating hinge knee prosthesis is a popular intervention in patients lacking stability with highly constrained total knee arthroplasty. Despite improvements in design, nonmechanical and mechanical complications continue to be a problem. Dislocation of the hinge has been widely described, mainly due to the component fracture. Few reports describe isolated dislocation of the rotating stem. We report a case of isolated disengagement of the rotating hinge mechanism, due to severe flexion gap imbalance, leading to subsequent posterior dislocation of the hinge and anterior knee dislocation, in a patient with a history of multiple total knee arthroplasty revisions. This case suggests the importance of the soft tissue balancing, the adequate patellar tracking, and use of a long cylindrical, minimally tapered rotating stem in hinge arthroplasty to minimize hinge dislocation.

Evaluation of stability of rotating hinge knee prostheses: a biomechanical study

Purpose. Rotating hinge knee prostheses should provide a stable situation following reconstruction. We performed a biomechanical analysis to establish the association between design of the central rotational stem (peg) and implant's stability, in a theoretical setting. Methods. Six different rotating hinge designs were tested, and three observers performed two different measurements with a custom made biomechanical apparatus and laterally directed pressure. The aim was to assign the degree of tilting of the peg within the vertical post-in channel by extending the distraction as well as the maximum amount of distraction before the peg's dislocation. An intraclass-correlation coefficient (ICC) was calculated to determine the observer's reliability. Results. Implant designs with cylindrical pegs of different lengths were superior to implant designs with conical or other shaped pegs concerning stability and maximum amount of distraction before dislocation, showing steep rising distraction-angular displacement curves. The ICC at 15 mm and 25 mm of distraction revealed high interobserver reliability (P < 0.001). Conclusion. The biomechanical analysis showed that rotating hinge prostheses with long and cylindrical pegs have the highest stability at any given amount of distraction. Designs with shorter and markedly tapered pegs may become unstable under conditions of mild joint distraction which has to be proven in future in vivo investigations.

Surgical technique: Computer-generated custom jigs improve accuracy of wide resection of bone tumors

BACKGROUND

Manual techniques of reproducing a preoperative plan for primary bone tumor resection using rudimentary devices and imprecise localization techniques can result in compromised margins or unnecessary removal of unaffected tissue. We examined whether a novel technique using computer-generated custom jigs more accurately reproduces a preoperative resection plan than a standard manual technique.

DESCRIPTION OF TECHNIQUE

Using CT images and advanced imaging, reverse engineering, and computer-assisted design software, custom jigs were designed to precisely conform to a specific location on the surface of partially skeletonized cadaveric femurs. The jigs were used to perform a hemimetaphyseal resection.

METHODS

We performed CT scans on six matched pairs of cadaveric femurs. Based on a primary bone sarcoma model, a joint-sparing, hemimetaphyseal wide resection was precisely outlined on each femur. For each pair, the resection was performed using the standard manual technique on one specimen and the custom jig-assisted technique on the other. Superimposition of preoperative and postresection images enabled quantitative analysis of resection accuracy.

RESULTS

The mean maximum deviation from the preoperative plan was 9.0 mm for the manual group and 2.0 mm for the custom-jig group. The percentages of times the maximum deviation was greater than 3 mm and greater than 4 mm was 100% and 72% for the manual group and 5.6% and 0.0% for the custom-jig group, respectively.

CONCLUSIONS

Our findings suggest that custom-jig technology substantially improves the accuracy of primary bone tumor resection, enabling a surgeon to reproduce a given preoperative plan reliably and consistently.

High infection rate outcomes in long-bone tumor surgery with endoprosthetic reconstruction in adults: a systematic review

BACKGROUND

Limb salvage surgery (LSS) with endoprosthetic replacement is the most common method of reconstruction following bone tumor resection in the adult population. The risk of a postoperative infection developing is high when compared with conventional arthroplasty and there are no appropriate guidelines for antibiotic prophylaxis.

QUESTIONS/PURPOSES

We sought to answer the following questions: (1) What is the overall risk of deep infection and the causative organism in lower-extremity long-bone tumor surgery with endoprosthetic reconstruction? (2) What antibiotic regimens are used with endoprosthetic reconstruction? (3) Is there a correlation between infection and either duration of postoperative antibiotics or sample size?

METHODS

We conducted a systematic review of the literature for clinical studies that reported infection rates in adults with primary bony malignancies of the lower extremity treated with surgery and endoprosthetic reconstruction. The search included articles published in English between 1980 and July 2011.

RESULTS

The systematic literature review yielded 48 studies reporting on a total of 4838 patients. The overall pooled weighted infection rate for lower-extremity LSS with endoprosthetic reconstruction was approximately 10% (95% CI, 8%-11%), with the most common causative organism reported to be Gram-positive bacteria in the majority of cases. The pooled weighted infection rate was 13% after short-term postoperative antibiotics and 8% after long-term postoperative antibiotics. There was no correlation between sample size and infection rate.

CONCLUSIONS

Infection rates of 10% are high when compared with rates for conventional arthroplasty. Our results suggest that long-term antibiotic prophylaxis decreases the risk of deep infection. However, the data should be interpreted with caution owing to the retrospective nature of the studies.

Early Functional Outcome of Resection and Endoprosthesis Replacement for Primary Tumor around the Knee

We evaluated functional outcomes for patients who underwent surgery for resection and endoprosthesis replacement for primary tumours around the knee. We used the Musculoskeletal Tumour Society Scoring System (MSTS) for functional evaluations to compare differences between distal femur (DF) and proximal tibia (PT) placements. The study sample included 34 cases of distal femur and 20 cases of proximal tibia endoprosthesis replacement. Primary tumours were classified as follows: 33 osteosarcoma, 20 stage III giant cell tumour (GCT) and one case of mesenchymal chondrosarcoma. The mean MSTS score for both DF and PT endoprosthesis together was 21.13 (70.43%), and The MSTS scores for DF was 21.94 (73.13%) and PT was 19.75 (65.83%) Infection developed in 7 cases and 5 of which were PT endoprosthesis cases. Three deep infections required early, two-stage revision and resulted in poor MSTS scores. We conclude that endoprosthesis replacement for primary bone tumours had early good to excellent functional outcome. There were no differences in functional outcomes when comparing distal femur endoprostheses with proximal tibia endoprostheses.

KEY WORDS

functional outcome, bone tumour, knee, and endoprosthesis.

Compress knee arthroplasty has 80% 10-year survivorship and novel forms of bone failure

BACKGROUND

Compliant, self-adjusting compression technology is a novel approach for durable prosthetic fixation of the knee. However, the long-term survival of these constructs is unknown.

QUESTIONS/PURPOSES

We therefore determined the survival of the Compress prosthesis (Biomet Inc, Warsaw, IN, USA) at 5 and 10 actuarial years and identified the failure modes for this form of prosthetic fixation.

METHODS

We retrospectively reviewed clinical and radiographic records for all 82 patients who underwent Compress knee arthroplasty from 1998 to 2008, as well as one patient who received the device elsewhere but was followed at our institution. Prosthesis survivorship and modes of failure were determined. Followup was for a minimum of 12 months or until implant removal (median, 43 months; range, 6-131 months); 28 patients were followed for more than 5 years.

RESULTS

We found a survivorship of 85% at 5 years and 80% at 10 years. Eight patients required prosthetic revision after interface failure due to aseptic loosening alone (n = 3) or aseptic loosening with periprosthetic fracture (n = 5). Additionally, five periprosthetic bone failures occurred that did not require revision: three patients had periprosthetic bone failure without fixation compromise and two exhibited irregular prosthetic osteointegration patterns with concomitant fracture due to mechanical insufficiency.

CONCLUSIONS

Compress prosthetic fixation after distal femoral tumor resection exhibits long-term survivorship. Implant failure was associated with patient nonadherence to the recommended weightbearing proscription or with bone necrosis and fracture. We conclude this is the most durable FDA-approved fixation method for distal femoral megaprostheses.

LEVEL OF EVIDENCE

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

Failure of the rotating-hinge knee megaprosthesis

Recently, rotating hinge knee prostheses were applied more frequently due to improving modern implant designs. They are predominantly used in specific conditions with major bone defect or insufficiency of the collateral ligaments around the knee, often as salvage procedures. A case of rotating hinge knee megaprosthesis failure due to isolated tibial polyethylene stopper broken, which was never reported before, was investigated and treated in our institution. We suggested that rotating hinge knee prosthesis with incompetent medial collateral ligament is apt to failure due to the high valgus moment during gait. Sacrificing lateral collateral ligament or cutting the femur in slightly less than the normal 5° to 7° valgus may eliminate the risk of complication.

Comparison between Constrained and Semiconstrained Knee Allograft-Prosthesis Composite Reconstructions

Allograft-prosthesis composite (APC) can restore capsular and ligamentous tissues of the knee sacrificed in a tumor extirpation. We asked if performing APC would restore knee stability and allow the use of nonconstrained arthroplasty while preventing aseptic loosening. We retrospectively compared 50 knee APCs performed with non-constrained revision knee prosthesis (Group 1) with 36 matched APCs performed with a constrained prosthesis (Group 2). In Group 1, the survival rate was 69% at five and 62% at ten years. Sixteen reconstructions were removed due to complications: eight deep infections, three fractures, two instabilities, one aseptic loosening, one local recurrence, and one nonunion. In Group 2, the survival rate was 80% at five and 53% at ten years. Nine reconstructions were removed: 3 due to deep infections, 3 to fractures, and 3 to aseptic loosening. In both groups, we observed more allograft fractures when the prosthetic stem does not bypass the host-donor osteotomy (P > 0.05). Both groups had mainly good or excellent MSTS functional results. Survival rate and functional scores and aseptic loosening were similar in both groups. A rotating-hinge APC is recommended when host-donor soft tissue reconstruction fails to restore knee instability. The use of a short prosthetic stem has a statistical relationship with APC fractures.

Functional outcome of limb salvage surgery with mega-endoprosthetic reconstruction for bone tumors

BACKGROUND

The use of a mega-endoprosthesis has become the method of choice for reconstruction after bone tumors. In this study, we sought to determine the functional outcome and complications associated with mega-endoprosthesis.

METHODS

A retrospective review of the charts of 16 patients who had undergone resection of bone tumors followed by reconstruction with mega-endoprosthesis between 2006 and 2011 was performed. Functional evaluation was based on the Musculoskeletal Tumor Society (MSTS) scoring system. Complications of the procedures were also analyzed.

RESULTS

Eight men and eight women at an average age of 36.7 years were included in the study. The tumor involved lower limb in 14 patients and upper limb in 2 patients. The average MSTS functional score was 72.3 ± 15. Excellent results were achieved in six patients, good in five, moderate and fair in two each and poor in one. Complications occurred in eight patients. Two patients had aseptic loosening of the femoral component of total knee replacement. Flap necrosis occurred in two patients, both of whom required latissimus dorsi free flap for coverage of total knee prosthesis. One patient underwent revision of femoral component subsequent to knee dissociation. Local recurrence of tumor, patellar tendon rupture and foot drop occurred in one patient each.

CONCLUSION

Mega-endoprosthetic reconstruction in limb salvage provides good functional outcome in patients with bone tumors.

In vivo testing of knee stability after rotating-hinge total knee arthroplasty: a comparison of 2 knee systems

Rotating-hinge knee prostheses are used for reconstruction in cases of severe articular compromise and major bone loss. Biomechanical studies revealed that rotating-hinge designs with long and cylindrical pegs are more stable than devices with short and more tapered ones. Twenty-five patients underwent clinical examination using ultrasound, radiographs, and 3 different rating systems to examine the in vivo stability and functional outcome of 2 rotating-hinge knee systems. Overall, the study revealed that a stable reconstruction could be achieved with both tested devices, with good functional outcome. The results for medial and lateral lift-off during flexion and extension in ultrasonography were comparable, whereas the measured distraction of the Limb Preservation System (LPS/M.B.T.; DePuy, Warsaw, Indiana) was lower compared with the S-ROM Noiles prostheses (DePuy). The implant, the new formed capsule, and the remaining soft tissues have to maintain joint stability. Soft tissue reconstruction, especially the medial gastrocnemius flap, and the newly formed periprosthetic scar seems to prevent distraction of several millimeters. In addition, determining the lift-off with ultrasonography showed that the shape of the peg does not influence implant's stability against lateral directed forces.

Prophylactic antibiotic regimens in tumour surgery (PARITY): protocol for a multicentre randomised controlled study

INTRODUCTION

Limb salvage with endoprosthetic reconstruction is the standard of care for the management of lower-extremity bone tumours in skeletally mature patients. The risk of deep postoperative infection in these procedures is high and the outcomes can be devastating. The most effective prophylactic antibiotic regimen remains unknown, and current clinical practice is highly varied. This trial will evaluate the effect of varying postoperative prophylactic antibiotic regimens on the incidence of deep infection following surgical excision and endoprosthetic reconstruction of lower-extremity bone tumours.

METHODS AND ANALYSIS

This is a multicentre, blinded, randomised controlled trial, using a parallel two-arm design. 920 patients 15 years of age or older from 12 tertiary care centres across Canada and the USA who are undergoing surgical excision and endoprosthetic reconstruction of a primary bone tumour will receive either short (24 h) or long (5 days) duration postoperative antibiotics. Exclusion criteria include prior surgery or infection within the planned operative field, known colonisation with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus at enrolment, or allergy to the study antibiotics. The primary outcome will be rates of deep postoperative infections in each arm. Secondary outcomes will include type and frequency of antibiotic-related adverse events, patient functional outcomes and quality-of-life scores, reoperation and mortality. Randomisation will be blocked, with block sizes known only to the methods centre responsible for randomisation, and stratified by location of tumour and study centre. Patients, care givers and a Central Adjudication Committee will be blinded to treatment allocation. The analysis to compare groups will be performed using Cox regression and log-rank tests to compare survival functions at α=0.05.

ETHICS AND DISSEMINATION

This study has ethics approval from the McMaster University/Hamilton Health Sciences Research Ethics Board (REB# 12-009). Successful completion will significantly impact on clinical practice and enhance patients' lives. More broadly, this trial will develop a network of collaboration from which further high-quality trials in Orthopaedic Oncology will follow.

Failure rate of a rotating hinge knee design due to yoke fracture of the hinged tibial insert: a retrospective data analysis and review of the literature

PURPOSE

Rotating hinge knee prostheses are known to provide inherent stability. Yoke fractures of the hinged tibial insert of modern generation rotating hinge devices are a matter of continued concern. The aim of this study was to describe incidence and management of yoke fracture of the LPS™ hinged tibial insert.

METHODS

Retrospective data analysis of two institutions identified 40 patients with a LPS™ total knee arthroplasty. Implant survival and prosthetic complications was calculated according to Kaplan-Meier.

RESULTS

Out of the group of 40 patients, four fractures of the metal yoke occurred in four cases (failure rate: 10%). Furthermore, a second fracture occurred in two patients. The overall revision-free prosthetic survival was 57% at 38 months, while prosthetic survival until yoke fracture was 86% at 38 months.

CONCLUSION

Handling yoke fractures as mechanical complication includes replacing the hinged insert, stabilization of the joint and joint line height preservation in order to decrease the cantilever effect at the insert-base plate interface.

Revision of tumor prosthesis of the knee joint

Background

Among 40 patients with primary malignant tumors of the knee joint who underwent reconstruction of the affected limb with tumor prosthesis, revision was required in 7 due to stem breakage or loosening.

Subjects and methods

In the 7 cases undergoing revision, conditions and background factors at the time of breakage, the breakage site, time of revision, models of previous and new prostheses, stem diameters before and after revision, details of the revision (blood loss, operative time), and the presence or absence of adjuvant therapy were determined.

Results

The replacement site was the distal femur in 5 and proximal tibia in 2. Revision was performed 6 years and 2 months after the previous prosthesis placement on average. The broken prosthesis model was KMFTR in 4 and HMRS and the physio-hinge type in one each. Revision due to loosening was performed in a case requiring replacement with Growing Kotz prosthesis. The model was switched to HMRS in 3, and the stem diameter was changed to 12 mm in 3 KMFTR breakage cases. The mean stem diameters were 11.2 and 10.2 mm in the non-revision and revision groups. The respective resection rates were 36 and 45%. The mean functional evaluation was 70.1% before and 76.2% after revision.

Conclusion

To reduce the risk of tumor prosthesis breakage, the amount of bone resection should be limited to 30% or less in the affected bone, the stem diameter should be at least 12 mm, and the stem shape should be fitted to the anatomical shape of the femur.

Clinical outcomes of the KYOCERA Physio Hinge Total Knee System Type III after the resection of a bone and soft tissue tumor of the distal part of the femur

BACKGROUND AND OBJECTIVES

The KYOCERA Physio Hinge Total Knee System Type III (PHKIII) was developed to reconstruct bony defects of the distal femur. The PHKIII is originative in that the metallic parts are fully made of titanium alloy, and this prosthesis has a unique semi-rotating hinge joint and was designed especially for people with the Asian physical body-type. The clinical outcomes of the PHKIII after the resection of musculoskeletal tumors of the distal femur were evaluated.

METHODS

There were 41 males and 28 females with a median age of 48-years. The median duration of follow-up was 57 months.

RESULTS

Eleven early complications and 37 late complications were observed, including 10 recurrences, 7 deep infections, 7 aseptic loosenings, 4 stem breakages, 4 displacements of shaft cap, and one wear of rotation sleeve. Twenty four prosthesis (35%) required a secondary operation because of complications. The five-year overall prosthetic survival rates, -prosthetic survival rate without aseptic loosening, and -limbs preservation rate were 85%, 90%, and 86%, respectively. The mean functional score according to the classification system of the Musculoskeletal Tumor Society was 20.5 points (68%).

CONCLUSIONS

Although continuous follow-up is required, reconstructions using PHKIII are considered to achieve more acceptable functional results.

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.

Can bone scintigraphy predict the final outcome of pasteurized autografts?

OBJECTIVE

As pasteurization is becoming more widely used in limb salvage reconstruction, more study is required to understand about host-graft junction healing, graft revascularization and incorporation, and the incidence and type of complications among pasteurized autografts. This was mainly achieved by follow-up radiography. We aimed to clarify whether Tc99m bone scanning can be considered a reliable method in determining these three parameters.

MATERIALS AND METHODS

Twenty-seven osteosarcoma patients with pasteurized autograft reconstructions were retrospectively reviewed using available scintigraphic and radiographic follow-up every 6 months postoperatively for 36 months. Follow-up of the unhealed cases was continued for the maximum follow-up period available for each case beyond the original study period, ranging from 1 to 15 months. Tc99m uptake was classified as cold, faint, moderate and high uptake. Junction healing was classified as none, partial and complete healing.

RESULTS

Seventy percent of junctions united with a mean of 22 months. Ninety to 100% of junctions showed increased uptake (high or moderate) at one time of the study regardless of final outcome. 85% of the pasteurized grafts showed the characteristic "tramline appearance". Four grafts (15%) were complicated: pseudoarthrosis and implant failure (1), fractured plate (1), intramedullary nail (IMN) fracture (1), and prosthesis stem loosening in the host bone (1), with underlying unhealed junctions in all cases.

CONCLUSION

Bone scanning can determine the stages of the graft's rim revascularization and incorporation; however, it cannot detect or predict junction healing or occurrence of complications. Supplementary treatment of unhealed junctions showing either decreased junctional uptake or graft quiescence may be warranted. Otherwise, detection of distant metastasis and early local recurrence remains the main application of Tc99m scanning in the management of bone sarcomas.

Medium to long-term results after reconstruction of bone defects at the knee with tumor endoprostheses

BACKGROUND AND OBJECTIVES

Limb salvage and reconstruction with tumor endoprostheses is considered as therapeutic standard in the treatment of bone defects at the knee. Few studies report long-term results so far.

METHODS

Seventy-seven patients who had a cementless or cemented MUTARS endoprosthesis implanted were followed-up for a mean period of 46 months (3-128 months). The defects were due to primary tumor lesions in 69 cases or metastases in 8 cases. The distal femur (n = 49) or the proximal tibia (n = 28) was reconstructed predominantly with cementless implants (femur: 69%, tibia: 92%). The resection of the tumor was intraarticular in 46 and extraarticular in 31 patients.

RESULTS

After 10 years probability of limb salvage was 92% with a recurrence rate of 3%. Complications were frequent with a revision rate of 58% and lead to a cumulative probability of survival of the initially implanted prosthesis of 57% after 5 years. Locking mechanism failure (n = 15) and aseptic loosening (n = 13) were the most frequent failure modes.

CONCLUSIONS

Regardless of achieving a low recurrence rate and satisfactory functional results, we found a high complication rate after implantation of a megaprosthesis. This was particularly evident for extraarticular resections and cemented fixation, which should be avoided when possible.

Megaprosthesis versus Condyle-sparing intercalary allograft: distal femoral sarcoma

Although functionally appealing in preserving the native knee, the condyle-sparing intercalary allograft of the distal femur may be associated with a higher risk of tumor recurrence and endoprosthetic replacement for malignant distal femoral bone tumors. We therefore compared the risk of local tumor recurrence between patients in these two types of reconstruction groups. We retrospectively reviewed 85 patients (mean age, 22 years; range, 4-82 years), 38 (45%) of whom had a condyle-sparing allograft and 47 (55%) of whom had endoprostheses. The minimum followup for both groups was 2 years (mean, 7 years; range, 2-19 years). Local recurrences occurred in 11% (five of 47) of the patients having implants versus 18% (seven of 38) of the patients having allografts. Using time to local recurrence as an end point, the Kaplan-Meier survivorship of the implant group was similar to that of the condyle-sparing allograft group at 2, 5, and 10 years (93% versus 87% at 2 years, 87% versus 81% at 5 years, and 87% versus 81% at 10 years, respectively). The condyle-sparing allograft procedure offers the potential advantage of retaining the native knee in a young patient population while incurring no greater risk of local recurrence as those offered the endoprosthetic procedure.

LEVEL OF EVIDENCE

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

Compress periprosthetic fractures: interface stability and ease of revision

Periprosthetic fractures after massive endoprosthetic reconstructions pose a reconstructive challenge and jeopardize limb preservation. Compressive osseointegration technology offers the promise of relative ease of prosthetic revision, since fixation is achieved by means of a short intramedullary device. We retrospectively reviewed the charts of 221 patients who had Compress((R)) devices implanted in two centers between December, 1996 and December, 2008. The mean followup was 50 months (range, 1-123 months). Six patients (2.7%) sustained periprosthetic fractures and eight (3.6%) had nonperiprosthetic ipsilateral limb fractures occurring from 4 to 79 months postoperatively. All periprosthetic fractures occurred in patients with distal femoral implants (6/154, 3.9%). Surgery was performed in all six patients with periprosthetic femur fractures and for one with a nonperiprosthetic patellar fracture. The osseointegrated interface was radiographically stable in all 14 cases. All six patients with periprosthetic fracture underwent limb salvage procedures. Five patients had prosthetic revision; one patient who had internal fixation of the fracture ultimately underwent amputation for persistent infection. Periprosthetic fractures involving Compress((R)) fixation occur infrequently and most can be treated successfully with further surgery. When implant revision is needed, the bone preserved by virtue of using a shorter intramedullary Compress((R)) device as compared to conventional stems, allows for less complex surgery, making limb preservation more likely.

LEVEL OF EVIDENCE

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

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.

Impairment and disability following limb salvage procedures for bone sarcoma

Bone sarcomas are the fourth most common cancer in individuals under 25 years. Limb salvage procedures are popular for the treatment of osteosarcomas as they have functional and physiological benefits over traditional amputative procedures. The objective of this study was to apply disease specific measures to a group of intra-articular knee osteosarcoma patients and to evaluate structural and treatment variables predictive of the functional outcome scores. Twenty patients (10 female, 10 male) treated with tumour resection and endoprosthetic knee arthroplasty took part in the study. The Musculoskeletal Tumour Society (MSTS) rating scale and the Toronto Extremity Salvage Score (TESS) were used to assess impairment and disability respectively. Impairment was recorded as 83% and disability was recorded as 86% suggesting moderate to high function following limb salvage surgery. Task difficulty was shown to increase for activities requiring large knee flexion angles, presumably due to increased patellofemoral forces. Bivariate correlations revealed that loss of quadriceps musculature, knee extension strength and knee flexion range of motion were parameters moderately associated with the assessment instruments. ANOVA revealed no significant differences in impairment (P=0.962) or disability (P=0.411) between the differing types of prostheses. In conclusion clinicians and therapists should emphasise restoration of post-surgical range of motion and strength in order to enhance functional recovery.

Endoprosthetic replacement for primary tumours around the knee: experience from Peking University

In developing countries locally-made low-cost prostheses are mainly used in limb-salvage surgery to alleviate the economic burden. We retrospectively collected data on 104 patients treated by limb-salvage surgery between July 1997 and July 2005. We used a locally-designed and fabricated stainless-steel endoprosthesis in each case. Oncological and functional outcomes were evaluated at a mean follow-up of 47 months (12 to 118). A total of 73 patients (70.2%) were free from disease, nine (8.7%) were alive with disease, 19 (18.2%) had died from their disease and three (2.9%) from unrelated causes. According to the Musculoskeletal Tumor Society scoring system, the mean functional score was 76.3% (SD 17.8). The five-year survival for the implant was 70.5%. There were nine cases (8.7%) of infection, seven early and two late, seven (6.7%) of breakage of the prosthesis, three (2.9%) of aseptic loosening and two (1.9%) of failure of the polyethylene bushing. Multivariate analysis showed that a proximal tibial prosthesis and a resection length of 14 cm or more were significant negative prognostic factors. Our survival rates and Musculoskeletal Tumor Society functional scores are similar to those reported in the literature. Although longer follow-up is needed to confirm our results, we believe that a low-cost custom-made endoprosthesis is a cost-effective and reliable reconstructive option for limb salvage in developing countries.

Endoprosthetic proximal femur replacement: metastatic versus primary tumors

Few studies have examined the impact of underlying diagnosis on the functional and oncologic outcomes following endoprosthetic proximal femur replacement (PFR). We performed a retrospective review of 61 consecutive cemented bipolar PFR in 59 patients for treatment neoplastic lesions with a minimum follow-up of 24 months. Twenty-two patients had primary bone tumors and 39 had metastatic disease. Average follow-up for the 30 surviving patients was 55.4 months and the mean postoperative survival for the 29 patients who died was 12.2 months. Patients with primary tumors demonstrated significantly better functional outcomes than those with metastatic disease, with mean Musculoskeletal Tumor Society functional scores of 80.2 and 66.8%, respectively (p=0.0002). Age correlated inversely with functional scores (r=-0.48; p=0.0002), while femoral resection length did not. Preoperative pathologic fracture did not appear to adversely impact final functional outcomes. The Kaplan-Meier 5-year implant survival estimate was 92.5%, with aseptic loosening as the endpoint. Both functional results and survival are increased for primary tumors versus metastatic disease following PFR. However, PFR results in excellent local disease control, reliable pain relief and good functional results in both groups, with prosthesis survival exceeding that of the patient in many cases.

Implant design and resection length affect cemented endoprosthesis survival in proximal tibial reconstruction

Endoprosthetic reconstruction of the proximal tibia continues to pose many challenges. A retrospective analysis of 44 consecutive patients who underwent cemented proximal tibial replacement were included to investigate if patient age, surgical stage, type of implant, stem diameter, or resection length could be associated with implant failure. Fifteen patients (34%) suffered prosthetic failure, 7 due to infection. Prosthetic-related complications occurred in 13 patients (30%). Custom design prosthesis and longer length of resection were significantly associated with prosthesis survival in a Cox regression analysis (P = .001, hazard ratio = 8.747 and P = .044, hazard ratio = 1.217, respectively). Cemented proximal tibial replacement offers a functional knee, but reducing risk of complications still remains challenging. Prosthetic design and length of resection affect overall cemented endoprosthesis survival.