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

Principles of Defect Reconstruction After Wide Resection of Primary Malignant Bone Tumors of the Calcaneus: A Contemporary Review

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Characteristics and Epidemiology of Megaprostheses Infections: A Systematic Review

BACKGROUND

Megaprostheses were first employed in oncological orthopedic surgery, but more recently, additional applications have arisen. These implants are not without any risks and device failure is quite frequent. The most feared complication is undoubtedly the implants' infection; however, the exact incidence is still unknown. This systematic review aims to estimate in the current literature the overall incidence of megaprosthesis infections and to investigate possible risk/protective factors.

METHODS

We conducted a systematic search for studies published from July 1971 to December 2023 using specific keywords. To be included, studies needed to report either the megaprosthesis anatomical site, and/or whether the megaprosthesis was coated, and/or the surgical indication as oncological or non-oncological reasons.

RESULTS

The initial literature search resulted in 1281 studies. We evaluated 10,456 patients and the overall infection rate was 12%. In cancer patients, the infection rate was 22%, while in non-oncological patients, this was 16% (trauma 12%, mechanical failure 17%, prosthetic joint infections 26%). The overall infection rates comparing coated and uncoated implants were 10% and 12.5%, respectively.

CONCLUSIONS

The number of megaprosthesis implants is increasing considerably. In traumatological patients, the infection rate is lower compared to all the other subgroups, while the infection rate remains higher in the cancer patient group. As these devices become more common, focused studies exploring epidemiological data, clinical outcomes, and long-term complications are needed to address the uncertainties in prevention and management.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Patient-Reported Outcomes and Range of Motion Following Knee Arthroplasty Using a Megaprosthesis in Non-Oncological Patients: A Systematic Review

BACKGROUND

This review aimed to determine outcomes following megaprostheses in non-oncological indications for knee arthroplasty, including range of motion (ROM) and patient-reported outcome measures of function, pain, and quality of life (QoL).

METHODS

A search of MEDLINE, Embase, and Cochrane via Ovid and PubMed between January 2003 and June 2023 was conducted. Studies reporting function, pain, ROM, and/or QoL in non-oncological patients who have received knee megaprostheses were included. Studies with sample sizes (n ≤ 5) were excluded. The risk of bias was assessed using the Downs and Black Quality Checklist for Health Care Intervention Studies. Central tendency measures (mean or median) were reported at each time point, and dispersion measures were extracted and reported whenever data were available.

RESULTS

A total of 30 studies (involving 1,294 megaprostheses) were included. Of which, 14 of 30 studies reviewed patients who had mixed indications; 14 of 30 looked at fracture only; 1 of 30 focused on distal femur nonunion; and 1 of 30 focused on patients who had periprosthetic infections. The average patient follow-up time was 40.1 months (range, 1.0 to 93.5). Most studies presented a high risk of bias (27 of 30), while a few (3 of 30) presented a low risk of bias. Improvements from preoperative baseline were observed in 85.7% of studies that reported baseline and follow-up data for function (12 of 14), 100.0% pain (4 of 4), 90.9% ROM (10 of 11), and 66.6% QoL (2 of 3).

CONCLUSIONS

Favorable function, pain, ROM, and QoL outcomes following knee megaprostheses in non-oncological patients were observed. Heterogeneity in outcome measures and follow-up periods prevented the pooling of data. Future comparative studies are warranted to enhance the body of evidence relating to knee megaprostheses in non-oncological patients.

Periprosthetic distal femur fractures around total knee replacements: A comprehensive review

With a growing number of patients undergoing total knee replacements globally, coupled with an elderly population, the incidence of periprosthetic fractures around total knee replacements is increasing. As such, this is a highly topical subject that is gaining increasing interest within the orthopaedic community. This review provides a narrative synthesis of the most contemporary literature regarding distal femoral periprosthetic fractures. We review the related epidemiology, initial patient evaluation, the evolution and relevance of the classification systems and treatment options, particularly related to endoprosthetics and hybrid fixation constructs. The latest orthopaedic evidence related to this topic has been included.

Knee function, quality of life, pain, and living conditions after distal femoral resection knee arthroplasty for non-tumor indications

BACKGROUND

Distal femoral resection knee arthroplasty is a limb salvage procedure. The impact of distal femoral resection arthroplasty on patient function and health status is unknown. The aim of this study was to report knee function, quality of life, knee pain, and living conditions after distal femoral resection knee arthroplasty for non-tumor indications.

METHODS

Of 52 patients (52 knees) undergoing distal femoral resection knee arthroplasty in a single institution between 2012 and 2021, 22 were excluded as 3 patients had ≤90 days follow-up, 6 had died, and 13 declined or were unable to participate for unrelated reasons. Thus, 30 patients were included and interviewed by telephone in March 2021 (mean follow-up 3.5 years after surgery). Patient completed the Oxford Knee Score (0-48, 48 best), EQ-5D-5L, and the Copenhagen Knee ROM, and information on pain and living conditions was obtained.

RESULTS

The mean age was 67.9 years (SD 13.6), and 21 (70%) were female. Mean total Oxford Knee Score was 29.9 (SD 10.5), mean Copenhagen Knee ROM flexion was 116° (SD 21.6), and mean extension was - 2° (SD10.1). Mobility aids were used by 18 (60%) patients, i.e. a cane (30%), walker (26.7%) or wheelchair (3.3%). Mean EQ-5D_index score was 0.70 (SD 0.22) and mean EQ-5D VAS score was 55.4 (SD 23.9). Nine (30%) patients used paracetamol or NSAID and 2 (6.7%) used opioids for knee pain. Mean VAS knee pain score was 1.30 (SD 2.2) at rest and 2.8 (SD 3.1) when walking. Most (90%) patients lived in their own home, with only 3 patients in nursing homes. Two-thirds (66.7%) required no home care, 5 (16.6%) received home care 1-2 times over 2 weeks, and 5 (16.6%) every day.

CONCLUSION

Distal femoral resection knee arthroplasty appears to be a viable treatment option for non-tumor indications. Acceptable patient outcomes were achieved in terms of functional status and quality of life, especially considering treatment alternatives such as femoral amputation.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Debridement, antibiotics, and implant retention in non-oncological femoral megaprosthesis infections: minimum 5 year follow-up

PURPOSE

Megaprostheses are increasingly utilised outside of the oncological setting, and remain at significant risk of periprosthetic joint infection (PJI). Debridement, antibiotic, and implant retention (DAIR) is an established treatment for PJI, however its use in non-oncological patients with femoral megaprostheses has not been widely reported. There are significant differences in patient physiology, treatment goals, and associated risks between these patient cohorts.

METHODS

We identified 14 patients who underwent DAIR for a PJI of their femoral megaprostheses, between 2000 and 2014, whom had their index procedure secondary to non-oncological indications. Patients were managed as part of a multidisciplinary team, with our standardised surgical technique including exchange of all mobile parts, and subsequent antibiotic therapy for a minimum of 3 months. Patients were followed up for a minimum of 5 years.

RESULTS

Patients included six proximal femoral replacements, five distal femoral replacements, and three total femoral replacements. No patients were lost to follow-up. There were six males and eight females, with a mean age of 67.2 years, and mean ASA of 2.3. Nine patients (64.3%) successfully cleared their infection following DAIR at a minimum of 5 year follow-up. Five patients (35.7%) required further revision surgery, with four patients cleared of infection. No patients who underwent DAIR alone suffered complications as a result of the procedure.

CONCLUSIONS

The use of DAIR in these complex patients can lead to successful outcomes, but the risk of further revision remains high. The success rate (64.3%) remains on par with other studies evaluating DAIR in megaprostheses and in primary arthroplasty. This study indicates judicious use of DAIR can be an appropriate part of the treatment algorithm.

LEVEL OF EVIDENCE

II.

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

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

Implant Survival, Clinical Outcome and Complications of Megaprosthetic Reconstructions Following Sarcoma Resection

Simple Summary

Malignant bone and soft tissue tumors are usually surgically removed with an envelope of healthy tissue as a barrier. If located in the long bones of the upper and lower extremity, this approach leads to a large bone defect commonly affecting a joint. One way to rebuild the bone defect and the neighboring joint is the use of a megaprosthesis that is anchored in the remaining bone comparable to a conventional joint replacement. In general this approach is popular as it provides early stability and allows the affected patient to begin rehabilitation early on. However, complications leading to long-term unplanned reoperation are common. This article provides an overview of current implant survival, types of complication and long-term outcomes of megaprostheses used following tumor resection.

Abstract

Megaprosthetic reconstruction of segmental bone defects following sarcoma resection is a frequently chosen surgical approach in orthopedic oncology. While the use of megaprostheses has gained popularity over the last decades and such implants are increasingly used for metastatic reconstructions and in non-tumor cases, there still is a high risk of long-term complications leading to revision surgery. This article investigates current implant survivorship, frequency and types of complications as well as functional outcomes of upper and lower limb megaprosthetic reconstructions.

Different outcomes after proximal femoral replacement in oncologic and failed revision arthroplasty patients - a retrospective cohort study

Background

Proximal femoral replacement (PFR) is a technically demanding procedure commonly performed to restore extensive, oncological or non-oncological bone defects in a severely debilitated patient collective. Depending on different indications, a varying outcome has been reported. The aim of the study was to assess the functional outcomes and complication rates of PFR with the modular Munich-Luebeck (MML) femoral megaprosthesis (ESKA/Orthodynamics, Luebeck, Germany), and to highlight outcome differences in patients treated for failed revision total hip arthroplasty (THA) or malignant bone disease.

Methods

A retrospective review of patients treated with PFR for failed THA or malignant tumor disease between 2000 and 2012 was performed. Patient satisfaction, functional outcome (VAS, SF-12, MSTS, WOMAC, TESS), complications and failure types (Henderson’s failure classification) were assessed. A Kaplan-Meier analysis determined implant survival.

Results

Fifty-eight patients (age: 69.9 years, BMI: 26.7 kg/m², mean follow-up: 66 months) were included. The mean SF-12 (physical / mental) was 37.9 / 48.4. MSTS averaged 68% at final follow-up, while mean WOMAC and TESS scored 37.8 and 59.5. TESS and WOMAC scores demonstrated significantly worse outcomes in the revision group (RG) compared to the tumor group (TG). Overall complication rate was 43.1%, and dislocation was the most common complication (27.6%). Implant survival rates were 83% (RG) and 85% (TG; p = n.s.) at 5 years, while 10-year survival was 57% (RG) and 85% (TG, p < 0.05).

Conclusions

PFR is a salvage procedure for restoration of mechanical integrity and limb preservation after extensive bone loss. Complications rates are considerably high.

Functional outcomes and 10-year implant survival rate were worse in the RG compared to the TG. Strict indications and disease-specific patient education are essential in preoperative planning and prognosis.

Intermediate to Long-Term Follow-up of Distal Femoral Replacements in the Treatment of Neoplastic Disease About the Knee

Background

Limb salvage procedures have become more prevalent in orthopedic oncology. Endoprostheses have been used successfully to reconstruct large skeletal deficits. The aim was to review intermediate to long-term follow-up of distal femoral replacements in the setting of neoplastic disease about the knee.

Methods

This was a single-center retrospective cohort study from 1997 to 2018 in a national referral center for oncology. The secondary objectives were to describe morbidity and mortality in this cohort. We recorded the modes of failure using Henderson classification system, complications, revisions, and all further operations.

Results

Seventy-two distal femoral replacements were performed. Osteosarcoma was the most common indication (55 patients). Other indications included chondrosarcoma (7 patients), giant cell tumor (5 patients), Ewing’s sarcoma (2 patients), metastatic spread (2 patients), and leiomyosarcoma (1 patient). One-year mortality was 1.38% with an overall mortality of 13.8%, at the end of the study period. The 1-year revision rate was 4.2%, 30.5% for 10 years, and 38.8% for more than 15 years. The overall implant survival rate was 63.8%. The most common reasons for failure included aseptic loosening (16.6%), infection (16.6%), and local recurrence (9.7%) with an amputation rate of 6.9% in the cohort.

Conclusion

Neoplastic disease of the lower limb is associated with significant morbidity. Aseptic loosening (16.6%) and infection (16.6%) were the most common reasons for failure in this cohort.

Survivorship of Megaprostheses in Revision Hip and Knee Arthroplasty for Septic and Aseptic Indications: A Retrospective, Multicenter Study With Minimum 2-Year Follow-Up

Background

The use of megaprostheses in nononcologic patients has been associated with complication rates greater than 50%. In patients with prior periprosthetic joint infection (PJI) with subsequent two-stage reimplantation, this complication rate may be even higher. This study was to investigate the outcomes of megaprostheses in nononcologic patients undergoing revision hip/knee arthroplasty.

Methods

We retrospectively studied patients who underwent megaprosthesis replacements from 1999 to 2017 at 5 hospitals with minimum 24 months of follow-up. Patients were stratified based on history of prior PJI (septic vs aseptic) and location of the megaprosthesis (the hip or knee). Postoperative complications were classified as soft-tissue failure, aseptic loosening, structural failure, and infection.

Results

Of the 42 patients, 19 were in the septic cohort and 23 were in the aseptic cohort. The overall complication rate was 28.6%. Complication rates for the septic and aseptic cohorts were 32% and 26%, respectively (P = .74). By anatomic location, there were 2 of 13 (15%) and 10 of 29 (34%) complications in the hip and knee groups, respectively (P = .28). In the septic cohort, there were no (0%) complications in the hip group and 6 of 14 (43%) complications in the knee group (P = .13), all due to infection. In the aseptic cohort, there were 2 of 8 (25%) and 4 of 15 (27%) complications in the hip and knee groups, respectively (P = 1.0).

Conclusions

There is no difference in the postoperative complication rates between the septic or aseptic cohorts undergoing revision hip or knee megaprosthesis replacements. In patients with prior PJI, proximal femoral replacements have improved short-term survivorship compared with distal femoral or proximal tibial replacements.

How is the outcome of the Limb Preservation System™ for reconstruction of hip and knee?

BACKGROUND

Despite tremendous advantages in the development and application of megaprostheses in tumour and revision surgery, complications are still not infrequently observed. Only two studies investigating the outcome of the LPS™ system in the proximal femur and distal femur/proximal tibia have been published thus far. Herein, mid-term implant survival rates one of the largest cohort of patients treated with the LPS™-system are presented aiming tp answer: 1) How is the outcome of the LPS™ system in the proximal femur and distal femur/proximal tibia? 2) Which factors are associated with altered implant survival? 3) What is the cumulative risk of complications according to Henderson?

HYPOTHESIS

The LPS™-system is associated with high complication rates that depend on implant site, with infections being most common.

PATIENTS AND METHODS

Fifty-seven patients who received the LPS™-system at the proximal femur (n=31), distal femur (n=21) and proximal tibia (n=5) between 2004 and 2010 for oncological (n=40) or non-oncological (n=17) causes, were retrospectively included. Median follow-up was 5.0 years (range, 0-12.4 years). Complications were classified according to Henderson into instability/soft tissue failure (type 1), aseptic loosening (type 2), structural failure (type 3), periprosthetic infection (type 4), tumour progression (type 5). Competing-risk-analyses were applied to estimate implant survival with death as the competing event.

RESULTS

Twenty-six patients (45.6%) developed a complication, of whom 9 (29.0%) had a proximal femoral and 17 (65.4%) a distal femoral/proximal tibial implant. Type 4 complications were most common (n=11), followed by type 3 (n=6, including 2 yoke-fractures), type 1 and 2 (n=4 each), and type 5 (n=1). The only factor associated with the development of complications in the multivariate model was a distal femoral/proximal tibial implant (hazard-ratio: 7.418, 95% confidence-interval: 2.193-26.096, p=0.001), irrespective of reason for reconstruction and use of muscular flaps. The cumulative-incidence of failure including all complications was 34.3%, 40.7% and 67.1% at 3, 5 and 10 years, respectively.

DISCUSSION

The LPS™-system may be used for proximal femoral reconstructions both in the oncological and non-oncological setting. Rates of complications are higher in our cohort than reported in literature for other, comparable, megaprosthesis systems. Especially in the distal femur/proximal tibia, complication rates were high, partially attributable to the former implant design leading to fractures of the yoke-mechanism. As the implant has been remodelled after these issues became evident, there is no objection to use this megaprosthesis system today.

LEVEL OF EVIDENCE

IV, Observational Study.

Does a Competing Risk Analysis Show Differences in the Cumulative Incidence of Revision Surgery Between Patients with Oncologic and Non-oncologic Conditions After Distal Femur Replacement?

BACKGROUND

Distal femur replacement is frequently used for limb salvage after bone tumor resections. It is also used in patients with severe bone loss because of traumatic conditions or revision TKA. Some studies on distal femur replacement reported on revision-free survival without distinguishing between patients with oncologic diagnoses and those without, although these patients might be incomparable because of their differences in important patient- and disease-specific characteristics. This may lead to an inaccurate and undifferentiated interpretation of the results of survival analyses.

QUESTIONS/PURPOSES

(1) What is the overall cumulative incidence of revision surgery after cemented and cementless distal femoral replacement, as determined with a competing risk analysis? (2) Does the cumulative incidence of revision surgery change over time? (3) Are there differences in the cumulative incidence of revision surgery between patients with oncologic conditions and those without who are treated with cemented or cementless distal femoral replacement?

METHODS

A total of 403 patients were possible candidates for distal femoral replacement. Of these, 56 patients elected to undergo different procedures, 83 were excluded because an expendable growing prosthesis was implanted, and 28 were lost to follow-up. Therefore, 229 patients who underwent distal femoral replacement for oncologic or non-oncologic reasons between 1983 and 2016 were retrospectively included in this study. The type of fixation method (cemented or cementless) was obtained from the patients' medical records, operation reports, and radiographic analyses from plain radiographs. All radiographs were standardized and obtained at standard time intervals in our institution. No algorithm regarding the fixation approach was followed. According to our data, patients receiving cementless fixation were younger and therefore likely to be more active than those receiving cemented fixation. The median follow-up duration of the overall cohort was 85 months (range 0.1-391 months). Patients who died or had revision surgery before the 2-year minimum follow-up interval were adequately considered using competing risk calculation. The reasons for revision surgery were classified using the classification system proposed by the International Society for Limb Salvage. A competing risk analysis was performed to estimate the cumulative incidence function of revision, accounting for death as a competing event. To evaluate the influence of potential prognostic factors, including diagnosis (oncologic versus non-oncologic), fixation (cemented versus cementless), year of distal femoral replacement, age, and sex on the occurrence of revision surgery, univariate and multivariable Fine and Gray models were applied.

RESULTS

The competing risks analysis revealed cumulative incidences of revision surgery for any cause (Types 1 to 5) of 26% (95% CI, 20.3%-31.9%) at 12 months, 37.9% (95% CI, 31.3%-44.4%) at 24 months, 52.6% (95% CI, 45.1%-59.5%) at 5 years, and 58.2% (95% CI, 50.1%-65.4%) at 10 years for all patients. Rotating hinge-type prostheses showed a lower cumulative incidence of revision surgery (41.6%; 95% CI, 31.8%-51%) than fixed-hinge prostheses did (64%; 95% CI, 50.5%-74.5% ) at 5 years (Gray's test: p = 0.01). According to the multivariate Fine and Gray model, the year of surgery did not have any effect on the risk of revision surgery (1994 to 2003: hazard ratio 0.70; 95% CI, 0.46-1.07); 2004 to 2016: HR 0.83; 95% CI, 0.52-1.34; p = 0.26). The multivariate analysis, adjusted for disease, sex, age, cementation, and year of surgery, revealed a difference in the risk of revision surgery between patients with oncologic disease and those with non-oncologic disease (HR 0.44 for oncologic versus non-oncologic; 95% CI, 0.22-0.87; p = 0.02) and a reduction in the risk of overall revision with cemented fixation in patients with oncologic disease (HR 0.53; 95% CI, 0.29-0.98; p = 0.03).

CONCLUSION

This study indicates that even with newer implants, there was a high incidence of revision surgery after distal femoral replacement. According to our analysis, patients with oncologic diagnoses have a lower likelihood of revision when the stem is cemented whereas the type of fixation did not impact patients with non-oncologic diagnoses. Because of differences in patient demographics (age, etiology of disease, and use of chemotherapy) and outcomes of fixation, oncologic and non-oncologic patients should be analyzed separately in survival studies about distal femoral replacement.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Retrieval Analysis of Modern Knee Tumor Megaendoprosthesis Shows Considerable Volumetric Metal Wear Generated at the Rotating Hinge

Frequently occurring damage, as well as elevated blood metal ion levels, are reported in relation to a tumor and revision system for total knee arthroplasty (TKA), which applies a rotating hinge coupling with a metal-on-metal (MoM) articulation. As the patient collective for this specific system is small, there is no data on wear generated from the couplings. In this study, wear volume and influencing parameters were investigated at 44 retrieved TKAs with MoM couplings. A scoring system rating frequently occurring abrasive wear between 0 (no wear) and 3 (distinct wear) was established. The wear score was correlated to time in vivo, bone resection length, patient weight and polyethylene inlay damage. Volumetric wear was estimated applying coordinate measurements. An elevated wear score of two or higher was found in 43% of cases. The mean wear rate accounted to 7.8 mm³/year. The main influencing coefficient for the extent of wear is time in vivo. We found a tendency for higher wear scores with higher inlay degradation scores. Patient weight and bone resection length did not impact coupling wear. Assessment of wear damage by a semi-quantitative scoring system has proven to be a reliable option for non-destructive coupling evaluation. The generated wear volume is high.

Long-Term Results of Total Knee Arthroplasty with Contemporary Distal Femoral Replacement

BACKGROUND

Distal femoral replacement (DFR) is a salvage option for complex primary and revision total knee arthroplasty (TKA). Although excellent immediate fixation and weight-bearing are achieved, there is a paucity of data on long-term outcomes of TKA with DFR. The purpose of the present study was to determine implant survivorship, clinical outcomes, and radiographic results of TKAs with contemporary DFR components in a large series.

METHODS

We identified 144 consecutive TKAs performed with DFR for non-oncologic indications from 2000 to 2015 at a single academic institution. Indications for the index DFR included 66 (46%) for native (n = 11) or periprosthetic (n = 55) femoral fracture, 40 (28%) for staged treatment of periprosthetic joint infection, 28 (19%) for aseptic TKA loosening, and 10 (7%) for other indications. Porous metal cones were used to augment femoral fixation in 28 patients (19%) and tibial fixation in 38 patients (26%). Outcomes included cumulative incidence of revision and reoperation (utilizing a competing risk model), Knee Society scores, and radiographic results. The mean age at the time of index DFR was 72 years, and 65% of patients were female. The mean follow-up was 5 years (range, 2 to 13 years) for the 111 patients who did not undergo revision, had not died, and were not lost to follow-up.

RESULTS

The 10-year cumulative incidences of revision for aseptic loosening, all-cause revision, and any reoperation were 17.0%, 27.5%, and 46.3%, respectively. There was an increased risk of reoperation in patients who underwent index DFR for aseptic TKA loosening (hazard ratio [HR], 2.30; p = 0.026) or periprosthetic joint infection (HR, 2.18; p = 0.022) compared with periprosthetic or native femoral fractures. However, there was no difference in risk of revision for aseptic loosening or all-cause revision based on the original operative indication. The mean Knee Society score increased from 45 preoperatively to 71 at the time of the latest follow-up (p < 0.001). Radiographic loosening was observed in 8 unrevised DFRs (7%). There were 7 above-the-knee amputations performed at the time of the final follow-up, all for intractable periprosthetic joint infection.

CONCLUSIONS

TKAs with contemporary DFR had high 10-year cumulative incidences of both revision and reoperation, underscoring the salvage nature of this procedure as a final reconstructive option. Most patients experienced substantial clinical improvements with this end-stage revision procedure.

LEVEL OF EVIDENCE

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

Acute Distal Femoral Replacement for Fractures About the Knee in the Elderly

Distal femoral replacement (DFR) is a reasonable treatment option when used for select indications. In the setting of comminuted intra-articular distal femoral fractures, distal femoral arthroplasty should be considered in low-demand patients with poor bone quality. This article summarizes the existing literature plus the authors' personal experience with DFR use for distal femoral fractures of the native knee.

Total knee arthroplasty with distal femoral replacement is associated with an important complication rate. A case series

BACKGROUND

With the aging population and an increasing number of total knee arthroplasties (TKAs) performed yearly worldwide, revision surgeries for many causes (septic or aseptic loosening, periprosthetic femoral fractures (PDFF), non-unions, malunions) are more frequent and challenging. Distal femoral replacement (DFR) is sometimes the only option to restore knee function and quality of life. DFR in non-oncologic patient is still a rare indication and few reports are published on this topic, with a non-consistent variety of functional results, complication rates and survivorship.

METHODS

We present a retrospective series of patients who underwent a DFR for a non-oncologic indication between 2010 and 2017. Nineteen patients were available for a full evaluation (clinical and radiological) with a mean follow-up of 48.3 months (range 15-99). Goniometry was performed at the six-week postoperative visit. Complications were reported. Osteolysis and/or signs of aseptic loosening were described using the Knee Society Radiographic Evaluation. Survivorship was calculated for aseptic loosening, infection, and revision for any cause.

RESULTS

The mean Knee Society Score was good for the pain score (42.2, range 10-50) and fair for the function score (60.6, range 0-100). Four deep infections (21.1%) were successfully treated with mobile parts exchange and debridement. Three patients presented femoral osteolysis ≥5 years after the DFR. Survivorship for aseptic loosening was 100% at four years, 81.8% after five years and 53.3% after eight years.

CONCLUSIONS

TKA with DFR is a valuable option for patients with a severe bone loss and poor bone quality in the distal femur. DFR restores an acceptable quality of life but is related to an important complication rate.

Megaprosthesis versus Allograft Prosthesis Composite for massive skeletal defects

Massive skeletal defects are encountered in the setting of tumors necessitating excision, failed total hip arthroplasty with periprosthetic bone loss, periprosthetic fracture, complex trauma, multiple failed osteosynthesis and infection. Reconstruction of the segmental defects poses a tremendous challenge to the orthopaedic surgeons. The goal of osseous reconstruction of these defects is to restore the bone length and function. Currently the most commonly employed methods for reconstruction are either a megaprosthesis or an Allograft Prosthesis Composite (APC). Megaprosthesis, initially created for the treatment in neoplastic pathologies are being used for the non-neoplastic pathologies as well. The longevity of these implants is an issue as majority of the patients receiving them are the survivors of oncologic issue or elderly population, both in which the life expectancy is limited. However, the early complications like instability, infection, prosthetic breakage and fixation failure have been extensively reported in several literatures. Moreover, the megaprostheses are non-biological options preventing secure fixation of the soft tissue around the implant. The Allograft Prosthesis Composites were introduced to overcome the complications of megaprosthesis. APC is made of a revision-type prosthesis cemented into the skeletal allograft to which the remaining soft tissue sleeve can be biologically fixed. APCs are preferred in young and low risk patients. Though the incidence of instability is relatively low with the composites as compared to the megaprosthesis, apart from infection, the newer complications pertaining to APCs are inevitable that includes non-union, allograft resorption, periprosthetic fracture and potential risk of disease transmission. The current review aims to give an overview on the treatment outcomes, complications and survival of both the megaprostheses and APCs at different anatomic sites in both the upper and lower limbs.