A systematic review of endoprosthetic replacement for non-tumour indications around the knee joint

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.

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.

Diagnosis and management of METS-Stanmore Morse taper failure

We describe clinical semiology in 6 cases of METS-Stanmore distal femoral Morse taper impaction failure: from obvious forms with intraprosthetic dislocation to chronic forms with less obvious symptoms: instability, piston sensation, rotational disorder in gait. The diagnostic procedure in chronic forms is described, notably with dynamic examination under fluoroscopy. Reduction and re-impaction by external maneuver can be attempted; in case of failure or of any suspicion of taper disassembly, the 2 modular implant components have to be replaced. Finally, we provide a review of the literature on this rare but serious complication. LEVEL OF EVIDENCE: IV.

Satisfactory medium- to long-term outcomes of cemented rotating hinge prosthesis in revision total knee arthroplasty

Aims

The aim of this study was to evaluate medium- to long-term outcomes and complications of the Stanmore Modular Individualised Lower Extremity System (SMILES) rotating hinge implant in revision total knee arthroplasty (rTKA) at a tertiary unit. It is hypothesized that this fully cemented construct leads to satisfactory clinical outcomes.

Methods

A retrospective consecutive study of all patients who underwent a rTKA using the fully cemented SMILES rotating hinge prosthesis between 2005 to 2018. Outcome measures included aseptic loosening, reoperations, revision for any cause, complications, and survivorship. Patients and implant survivorship data were identified through both prospectively collected local hospital electronic databases and linked data from the National Joint Registry/NHS Personal Demographic Service. Kaplan-Meier survival analysis was used at ten years.

Results

Overall, 69 consecutive patients (69 knees) were included with a median age of 78 years (interquartile range 69 to 84), and there were 46 females (66.7%). Indications were septic revisions in 26 (37.7%), and aseptic aetiology in the remining 43 (62.3%). The mean follow-up was 9.7 years (4 to 18), and the overall complication was rate was 7.24%, all with patellofemoral complications. Failure rate with 'any cause revision' was 5.8%. There was one case of aseptic loosening of the femoral component. At ten years, 17/69 patients (24.63%) had died, and implant survivorship was 92.2%.

Conclusion

In our experience, the SMILES rotating hinge prosthesis achieves satisfactory long-term outcomes with ten-year implant survivorship of 92.2% and a patellofemoral complication rate of 7.24%.

Apparent trends in the use of femoral megaprostheses: an analysis from the National Joint Registry

BACKGROUND

Megaprosthetic replacement (MPR) of the femur is typically reserved for salvage or oncological reconstruction. Presently little is known about the provision of femoral MPRs performed nationally, the trends in indications for their use, and their outcomes beyond published unit-level data. Although the National Joint Registry (NJR) collects data as part of a mandatory arthroplasty audit process, MPR data entry on this platform is thought to be inconsistent. The aim of this study is to determine current trends for femoral MPR procedures as submitted to the NJR.

METHODS

Data for all procedures submitted to the NJR using the following implants were extracted: METS (Stanmore/Stryker), MUTARS (Implantcast), Segmental (Zimmer), GMRS (Stryker) and MEGA C (LINK). Pseudoanonymized data were analyzed through the NJR's research Data Access Portal and are reported using descriptive statistics.

RESULTS

A total of 1781 procedures were identified. Submitted cases increased for primary and revision hip and knee categories over the study period, although they plateaued in recent years. MPR implants were most commonly used in revision hip arthroplasty procedures. MPR use for the management of peri-prosthetic fractures has increased and now represents the most commonly reported indication for MPR use in both hip and knee revision categories. Few centers submitted large MPR case volumes (which were noted to be lower than published unit case series, indicating NJR under-reporting), and the vast majority of centers submitting MPR cases did so in low volume.

CONCLUSIONS

Due to the limitations identified, reported case volumes must be interpreted with caution. An MPR-specific NJR data entry form has been developed to allow more accurate and tailored reporting of MPR procedures, to support specialist service provision, and to provide meaningful data for future research.

Distal Femoral Replacement and Extensor Mechanism Repair Reinforced With Synthetic Mesh for Distal Femur Fracture With Patellar Ligament Avulsion

Acute patellar ligament disruption in the setting of a distal femur fracture is an uncommon presentation with a variety of treatment options available to the practitioner. The following case report presents an 85-year-old female with a highly comminuted supracondylar distal femur fracture with intercondylar extension and a soft-tissue avulsion of the patellar ligament insertion discovered intraoperatively. A detailed technique review for acute patellar ligament repair with suture anchors and synthetic mesh reinforcement in the setting of distal femoral replacement is then provided. One-year follow-up revealed an intact extensor mechanism with minimal extensor lag and a painless gait. Surgeons faced with such a unique, complex problem may consider mesh augmentation of an acute patellar ligament repair while performing distal femoral replacement.

The Use of Megaprostheses in Nononcologic Lower-Extremity Total Joint Arthroplasty: A Critical Analysis Review

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As the number of primary total joint arthroplasty (TJA) procedures continues to rise, megaprostheses have found an emerging role in more complex revision arthroplasty cases that require additional reconstruction, stability, and restoration of function.

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Megaprosthesis options have evolved: in addition to cemented prostheses, cementless and even hybrid fixation designs optimize longevity. Proximal femoral replacement (PFR), distal femoral replacement (DFR), proximal tibial replacement (PTR), and total femoral replacement (TFR) are all limb salvage options in the setting of substantial bone loss, poor bone quality, and soft-tissue compromise.

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Dislocation is one of the most common complications after PFR, likely due to the loss of soft-tissue integrity, most notably the hip abductor musculature from the greater trochanter. The utilization of dual-mobility constructs, larger femoral heads, elevated acetabular liners, and constrained acetabular liners may reduce the risk of instability and improve overall hip function.

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Patients with megaprostheses may be more prone to periprosthetic joint infection and surgical site infection given multiple variables, such as the lengthy nature of the surgical procedure, prolonged wound exposure, extensive soft-tissue dissection and resection, poor soft-tissue coverage, and poorer host status.

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Despite advances in technology, complication and revision rates remain high after megaprosthesis reconstruction. Therefore, thorough attention to patient-specific factors must be considered for appropriate use of these constructs.

High reoperation and mortality rate after distal femoral replacement for periprosthetic knee fracture in the elderly

PURPOSE

To analyze the outcomes of elderly patients with periprosthetic fractures around the knee operated on with a distal femur replacement (DFR).

METHODS

We performed a retrospective case series study of eleven elderly patients who underwent DFR due to a periprosthetic fracture. Mean follow-up was 30.1 months (SD 28.1). Demographic, clinical and radiological data were reviewed. A descriptive analysis and a study of survival were conducted. Then, a comparative analysis between the patients who needed reoperation and did not need reoperation, and the patients who died and the patients who were alive during the follow-up was performed.

RESULTS

Mean age was 77.1 years (SD 13.9). Reoperation rate was 36%, being infection the most common complication (27%). The risk of reoperation increased with a longer time between fracture and surgery. The 36.4% of patients died during the follow-up. Older age, need of blood transfusion and need of early reoperation were related to a higher risk of mortality.

CONCLUSION

DFR could be a valuable option for knee periprosthetic fractures in elderly patients. However, surgeons should be aware of the high reoperation and mortality rate.

Distal Femoral Replacement and Periprosthetic Joint Infection After Non-Oncological Reconstruction: A Retrospective Analysis

BACKGROUND

Distal femoral replacement (DFR) is commonly used to manage massive bone loss around the knee arising from aseptic loosening, periprosthetic joint infection (PJI), and distal femoral fractures. A number of studies report the outcome of DFR with considerable variation in long-term survivorship. This study investigated the outcome of DFR for patients with aseptic failures, fractures, and PJI.

METHODS

A retrospective review of 182 patients who underwent DFR for non-oncological indications between 2002 and 2018 was conducted. Data collected included the following: indication, postoperative complications, reoperation, revision, and follow-up. Implant survivorship with Kaplan-Meier curves along with a log-rank test for different preoperative indications was performed. A Cox regression model was used to evaluate the risk of revision.

RESULTS

The overall postoperative complication rate was very high at 36%. The most common complication was PJI (17%). The rate of reoperation for any cause was 29.7%, and the revision rate was 13.7%. The most common cause of re-revision was PJI (7.1%). Revision-free survivorship of the DFR implant was 91.6% at 1 year, 87.9% at 2 years, 82.5% at 5 years, and 73.4% at 10 years. Patients who had a prior-PJI had the lowest survivorship compared to patients undergoing DFR for management of periprosthetic fracture and mechanical loosening. Additionally, the prior-PJI group was at a fourfold increased risk of postoperative PJI compared to the aseptic group.

CONCLUSION

DFR is a valuable reconstructive option for patients with massive bone loss around the knee. However, patients undergoing DFR are at high risk of complications, reoperations, and failure.

Very Distal Femoral Periprosthetic Fractures: Replacement Versus Fixation: A Systematic Review

OBJECTIVES

To synthesize all-cause reoperations and complications data as well as secondary clinical and functional outcomes, after the management of very distal femur periprosthetic fractures (vDFPFs) in a geriatric patient population with either a distal femoral locking plate (DFLP) or distal femoral replacement (DFR).

DATA SOURCES

MEDLINE, Embase, and Web of Science were searched for English language articles from inception to March 16, 2020, in accordance to the PRISMA guidelines.

STUDY SELECTION

Studies reporting the management of vDFPFs in adults older than 65 years with either a DFLP or DFR were included. To ensure this review solely focused on very distal femoral periprosthetic fractures, only fractures of the following classifications were included: (1) Lewis and Rorabeck type II or III, (2) Su and Associates' Classification of Supracondylar Fractures of the Distal Femur type III, (3) Backstein et al type F2, and/or (4) Kim et al type II or III.

DATA EXTRACTION

Three reviewers independently extracted data from the included studies. Study validity was assessed using the methodological index for nonrandomized studies (MINORS), a quality assessment tool for nonrandomized controlled studies in surgery.

DATA SYNTHESIS

Twenty-five studies with 649 vDFPFs were included for analysis. There were 440 knees in the DFLP group (mean age range: 65.9-88.3 years) and 209 knees in the DFR group (mean age range: 71.0-84.8 years). Because of the literature's heterogeneity, the data were qualitatively synthesized.

CONCLUSIONS

vDFPFs in the elderly treated with DFR underwent fewer reoperations relative to DFLP (0%-45% vs. 0%-77%, respectively). Time to weight-bearing was observably shorter in DFR studies relative to DFLP studies. Functional outcomes and postoperative range of motion indicated a trend for DFLP knees to outperform DFR knees. Future research should include prospective studies and cost-effectiveness evaluations to better understand the utility of DFR for these fractures.

LEVEL OF EVIDENCE

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

Megaprostheses in Nononcologic Hip and Knee Revision Arthroplasty

Megaprostheses as a means of limb salvage originated in orthopaedic oncology, and implant evolution was initially driven by developments within this field. Improvements in imaging modalities and in chemotherapeutics prolonged patient survival and promoted a transformation in the surgeon's mentality from salvage operation to functional limb reconstruction. As primary arthroplasty operations became more popular, megaprostheses found new utility in hip and knee revision arthroplasty. In this capacity, these implants provided much needed alternatives to traditional arthroplasty revision options for addressing massive bone loss and complex periprosthetic fractures. The indications for megaprostheses continue to expand with advances in design, stability, and overall longevity. Thus, greater numbers of orthopaedic surgeons in arthroplasty and traumatology have to be familiar with this technology. Importantly, each anatomic location presents unique considerations for reconstruction; however, additional variables such as the quantity of bone loss, the quality of remaining bone stock, and fracture type also influence implant selection. Ultimately, there is still much to be optimized in the use of megaprostheses for hip and knee revision arthroplasty. High multifactorial complication and revision surgery rates compared with conventional prostheses make these implants for many a "last resort" option.

Distal femoral replacement - Does length matter? Mid-term results for distal femoral replacements

BACKGROUND

Review of mid-term results (five years) for tumour and revision arthroplasty surgery using the Stanmore METS® distal femoral replacement.

METHODS

Data were collected retrospectively for 90 patients for procedures performed between 2002 and 2019. Kaplan-Meier survivorship for implant was estimated at five years post-op. Endpoints for survivorship analysis included revision for any cause and as per Henderson classification. Log rank test was used to compare implant survival for different categorical variables. Musculo-Skeletal Tumour Society (MSTS) score was used to estimate function.

RESULTS

Overall implant survival at five years was 76% (95% CI 66-86). Implants with a short body (<= 45 mm) had significantly better implant survival [87% (95% CI 78-99)] compared to those with larger bodies [63% (95% CI 48-82)] (logrank test, p = 0.031). There was no significant difference in implant survival for tumour and revision arthroplasty patients (logrank test, p = 0.61). Mean MSTS scores (median follow-up = 3.5 years) for tumour and revision arthroplasty patient were 71% and 63% respectively (Wilcoxon rank test, p < 0.05). Higher total number of surgeries was a significant predictor of patient mortality [HR = 0.7 (95% CI 0.49-0.99)]. Longer bodies were a significant predictor of implant failure [HR = 3.2 (95% CI 1.05-10.53), p < 0.05].

CONCLUSION

Overall outcome of Stanmore METS® distal femoral replacement at five years following tumour and revision arthroplasty reconstruction is comparable to the other implants.

Knee arthrodesis using a custom modular intramedullary nail in failed, infected knee arthroplasties: A concise follow-up note of 31 cases at a median of 13 years post-arthrodesis

INTRODUCTION

Knee arthrodesis utilizes an arthrodesis nail as a salvage technique for infected total knee arthroplasty (TKA), especially when the extensor mechanism is damaged, or the skin is compromised. This implant helps to minimize or prevent leg length discrepancy, while allowing immediate weight bearing without requiring bone fusion. However, there is a risk of infection. Surgical revisions were required in 19% of patients at 50 months' follow-up in our team's initial 31-patient case series. Since there is little long-term outcome data, we reviewed this same group of patients after a mean of 13 years to determine: (1) the implant's long-term survival, (2) the functional outcomes, (3) the microbiological changes in revision cases.

HYPOTHESIS

The long-term survival of knee arthrodesis using an arthrodesis nail for failed infected TKA is acceptable.

MATERIAL AND METHODS

Thirty-one patients operated on between January 2005 and December 2008 were retrospectively included in the initial study. The functional outcomes consisted of pain on a visual analog scale (VAS), neuropathic pain (DN4) and the Oxford Knee Score. All surgical revisions were documented with repeat microbiology samples.

RESULTS

The median follow-up time was 13.1 years [11.5-13.5]. No mechanical failure (implant failure or aseptic loosening) was observed. Eight patients were re-operated on due to new infections. The nail had to be removed in five of these patients. None of the patients required an amputation. Among the eight patients who were re-operated on, only two (25%) had been re-operated on since the initial study and underwent a two-stage arthrodesis revision. At 10 years, the cumulative incidence of surgical revision at the knee was 26% [95% CI: 12%-43%] and 16% [95% CI: 5.7%-31%] for an implant change. Six (75%) of the re-operated patients had their revision within the first 72 months of the initial TKA, while 4 (50%) had it within the first 26 months. Among the 15 patients who were still alive, the median Oxford Knee Score was 17/48 [12-28]. At the final assessment, the median pain level was 0 [0-5], although 4 of the 10 analyzable patients (of the 15 living patients, 3 had a cognitive impairment and 2 refused to participate) had neuropathic pain and pain on VAS of 3/10. The microbiologic findings were the same during the surgical revision in five of the eight re-operated patients (62%); however, one patient who had a Staphylococcus aureus infection had acquired a resistance to methicillin. In one patient, only one of the two bacteria identified initially was still present (methicillin-susceptible Coagulase-negative staphylococci [CNS]) and while in two patients, the infectious agent changed completely (shift from Gram-negative bacilli to methicillin-susceptible CNS, and the opposite for the other patient).

DISCUSSION

Knee arthrodesis with a custom modular intramedullary nail is a viable limb salvage option in failed infected TKA cases with long-term survival, and it is comparable to other arthrodesis techniques. In most cases, recurrence of the infection occurred in the short term (<72 months). Later recurrences of the infection (>72 months) were rarer and were found in only two of our patients (6%). There were no mechanical failures.

LEVEL OF EVIDENCE

IV; Retrospective cohort study.

Rotating-hinge prosthesis for aseptic revision knee arthroplasty: A multicentre retrospective study of 127 cases with a mean follow-up of five years

BACKGROUND

The use of third-generation rotating-hinge knee prostheses has increased considerably in recent years. The more anatomical design of these prostheses, together with their controlled rotation system that reduces constraints generated by the single degree of liberty, have produced better outcomes. The objective of this study was to evaluate the clinical and radiological outcomes of revision knee arthroplasty for aseptic failure using rotating-hinge prostheses.

HYPOTHESIS

The rotating-hinge knee prostheses currently used in France provide significant improvements in function and self-sufficiency of patients undergoing revision knee arthroplasty, with outcomes comparable to those reported with constrained condylar knees.

MATERIAL AND METHODS

A multicentre retrospective study was conducted in 17 centres, under the auspices of the SoFCOT. The cohort consisted of 127 patients (127 knees) operated on before 2013. The main reasons for knee revision were aseptic loosening, major instability, mechanical failure, and extensor apparatus failure. Function and self-sufficiency were assessed using the International Knee Society (IKS) score and the Devane score, respectively. Survival was defined with all-cause surgical revision as the end point.

RESULTS

Mean follow-up was 67.3±11.8 months (range, 13-180 months). Significant improvements (p<0.001) were seen in the total IKS score (+42 points), the IKS function score (+12 points), and the knee IKS score (+30 points). Paradoxically, the Devane score decreased by 0.44 point. The 5-year survival rate was 77% (95% confidence interval, 0.70-0.85). Postoperative complications developed in 29% of patients (infection, n=12; aseptic loosening, n=11; and fracture, n=7).

DISCUSSION

Rotating-hinge prostheses provide satisfactory outcomes of knee arthroplasty revision and remain an effective option for complex cases, confirming our working hypothesis. Self-sufficiency diminishes slightly. The long-term outcomes obtained using rotating-hinge prostheses are, however, less satisfactory than those observed with constrained condylar knees for aseptic TKA revision, and the complication rate is higher, although the population and local circumstances are different. Discernment is therefore in order when determining the indications of rotating-hinge prostheses.

LEVEL OF EVIDENCE

IV; retrospective cohort study.

Outcomes of Salvage Endoprostheses in Revision Total Knee Arthroplasty for Infection and Aseptic Loosening: Experience of a Specialist Centre

BACKGROUND

We aimed to evaluate the clinical and radiographic outcomes of complex salvage knee revision arthroplasty (rTKA) using endoprostheses with segmental bone loss.

METHODS

A consecutive study of patients who underwent salvage distal femoral replacement (DFR) or proximal tibial replacement (PTR) with a minimum 2- year follow-up (2005-2018). Patients who had acute DFR for periprosthetic fractures were excluded. Clinical outcomes, complications, reoperations, revision for any cause, loosening and mortality data were collected. Knee Society Score (KSS) at final follow up was used as a patient-reported-outcome-measure.

RESULTS

Thirty three consecutive patients were included; average age 79.6 years (range 58-89); 15 males/18 females. All had AORI-III massive bone defects and were reconstructed using DFRs; 6 patients had concurrent PTRs. The indication for salvage rTKA was infection in 16/33 (48.5%) and aseptic-loosening in the remaining 17 patients (51.5%). Complications rate was 12.1%; two patients had significant extensor lag; 1 patella dislocation and one recurrent infection. Median follow-up was 5 years (range 2-15) with median arc of flexion- extension of 100° (range 60-120). KSS was available for 29/33 patients with an average of 73.2 (range 51-86). Patients with infection as their indication had poorer KSS scores (66.1 vs. 81.6; P < 0.0001). Eleven patients have died at median 4 years postoperatively (range 2-7) for unrelated causes, none of the components have been revised to date with overall 80% patients' survivorship at 5 years.

CONCLUSIONS

The use of endoprostheses in salvage knee arthroplasty led to satisfactory medium-term clinical outcomes with an acceptable complication rate for this challenging group of patients with poorer functional scores for infection compared to aseptic loosening.

LEVEL OF EVIDENCE

Level IV.

Financial Impact of Inaccurate Coding Plus Cost-Effectiveness Analysis for Surgically Managed Patients With Periprosthetic Fractures

Background

An upward trend is seen in a number of periprosthetic fractures. Their management often requires complex surgical intervention, expert skills and expensive equipment. Hospitals get paid according to Healthcare Resource Group (HRG) tariffs. HRG gets generated once diagnoses, Charlson comorbidity (CC) index score, surgical procedures, investigations and length of stay have been coded for. Coding departments consist of non-clinicians. Although auditing systems are in and made of internal and external auditors, we hypothesized that multiple errors can still occur which may result in significant financial losses.

Objectives

To assess the accuracy of coding for management of periprosthetic fractures. To identify causes for inaccurate coding and assess the financial impact of highly complex trauma in a district general hospital (DGH).

Methods

Retrospective comparative analysis of case notes for patients with an M966 diagnosis code (periprosthetic fracture) between 1st November 2017 and 1st November 2018. All cases were analysed and data for primary procedure, primary diagnosis, secondary procedures and secondary diagnosis, comorbidities and length of stay were extrapolated and re-coded using the same software in use by the coding team. Costs incurred for each surgically managed patient were calculated using a rough estimate of cost of each procedure. Finally, cost-effectiveness analysis was carried out by comparing our calculated figures to the actual final claim by our institution. 

Results

Twenty-nine patients with the diagnosis of periprosthetic fracture were identified by the coding team using M966 code. A further case was identified by reviewing operating software (Operating Room Management Information System [ORMIS®]). In four cases (13.3 %), the primary diagnosis was coded incorrectly by the coding team. Overall coders accuracy for surgically managed patients (n=21) was 52% (n=11). This resulted in an estimated incurred loss of £25,000. Wrong/omitted site of surgery was found to be the most influential coder error with up to £8000 loss in one case (P<0.05). Cost-effectiveness analysis demonstrated the stark differences in costs for HRG tariffs when used in trauma setting vs non-trauma setting. Open reduction and internal fixation (ORIF) was associated with less financial loss to our trust with closer procedural costs to HRG tariff (average cost of £9200 for ORIF vs £22,030 for a massive endoprosthesis).

Conclusions

Surgeons should carefully review codes for such complex procedures before or soon after surgery. Wrong/omitted site of surgery is the key cause for losses in our cohort, followed by inadequate recording of comorbidities. Coders can only code for what is documented. Following cost-effectiveness analysis our study highlights the need for HRG tariffs to be revised for such procedures. The cost of ORIF vs massive endoprosthesis should be noted, signifying the implant costs when such specialised revision surgery performed over less expensive ORIF surgery.

Distal Femur Replacement Versus Surgical Fixation for the Treatment of Geriatric Distal Femur Fractures: A Systematic Review

OBJECTIVES

The management of geriatric distal femur fractures is controversial, and both primary distal femur replacement (DFR) and surgical fixation (SF) are viable treatment options. The purpose of this study was to compare patient outcomes after these treatment strategies.

DATA SOURCES

PubMed, Embase, and Cochrane databases were searched for English language articles up to April 24, 2020, identifying 2129 papers.

STUDY SELECTION

Studies evaluating complications in elderly patients treated for distal femur fractures with either immediate DFR or SF were included. Studies with mean patient age <55 years, nontraumatic indications for DFR, or SF with nonlocking plates were excluded.

DATA EXTRACTION

Two studies provided Level II or III evidence, whereas the remaining 28 studies provided Level IV evidence. Studies were formally evaluated for methodological quality using established criteria. Treatment failure between groups was compared using an incidence rate ratio.

DATA SYNTHESIS

Treatment failure was defined for both SF and arthroplasty as complications requiring a major reoperation for reasons such as mechanical failure, nonunion, deep infection, aseptic loosening, or extensor mechanism disruption. There were no significant differences in complication rates or knee range of motion between SF and DFR.

CONCLUSIONS

SF and DFR for the treatment of geriatric distal femur fractures demonstrate similar overall complication rates. Given the available evidence, no strong conclusions on the comparative effectiveness between the 2 treatments can be definitively made. More rigorous prospective research comparing SF vs. DFR to treat acute geriatric distal femur fractures is warranted.

LEVEL OF EVIDENCE

Therapeutic Level IV. See instructions for authors for a complete description of levels of evidence.

Periprosthetic knee infection reconstruction with a hinged prosthesis: Implant survival and risk factors for treatment failure

BACKGROUND

Severe bone and soft tissue defects are common after failed two-stage exchange arthroplasty for periprosthetic joint infection (PJI). There is a paucity of evidence on the outcomes of using a hinged prosthesis for knee PJI reconstruction during second-stage re-implantation, especially regarding implant survivorship, reinfection risk factors, and functionality after successful reconstruction.

METHODS

A total of 58 knee PJI patients with Anderson Orthopaedic Research Institute (AORI) type II/III defect and soft tissue insufficiency underwent reconstruction with hinged prosthesis. Enrolled patients adhered to a two-stage exchange arthroplasty protocol and were evaluated for a mean follow up of 65.1 months. Kaplan-Meier analysis was conducted for implant survivorship and infection-free survival. Multivariate analysis was used to determine independent risk factors for recurrent infections. Knee Society Score (KSS) was used to evaluate functional outcomes.

RESULTS

The survivorship of hinged prosthesis was 86.2% at 2 years and 70.2% at 5 years. Infection-free analysis revealed an estimation of 68.9% at 2 years and 60.6% at 5 years. Of the 58 patients, 13 (22.4%) developed recurrent PJI, three (5.2%) aseptic loosening, and one (1.7%) periprosthetic fracture. Multivariate analysis revealed that obesity (hazard ratio (HR), 3.11), high-virulent pathogen (HR, 3.44), and polymicrobial infection (HR, 3.59) were independent risk factors for reinfection. Patients showed a mean improvement of 32.8 ± 7.7 in Knee Society Clinical Score (KSCS) and 30.8 ± 11.0 in Knee Society Function Score (KSFS) after successful reconstruction (P<0.001).

CONCLUSIONS

Using hinged knee prosthesis for PJI reconstruction provided an overall implant survival of 70.2% and an infection-free survival of 60.6% at mid-term follow up. Obesity, virulent pathogens, and polymicrobial infections were independent risk factors for infection recurrence.

Non-neoplastic indications and outcomes of the proximal and distal femur megaprosthesis: a critical review

Purpose

Megaprosthesis or endoprosthetic replacement of the proximal and distal femur is a well-established modality for treatment of tumors. The indications for megaprosthesis have been expanded to the treatment of some non-neoplastic conditions of the knee and hip, with the severe bone loss associated with failed arthroplasty, communited fractures in the elderly with poor bone quality, and resistant non-union. Th aim of this study is to find out whether megaprosthesis of the knee and hip is successful in the treatment of non-neoplastic condtions. The study comprises a review of the indications, complications, and outcomes of megaprosthesis of the proximal and distal femur in non-neoplastic conditions of the knee and hip joints.

Methods

We extensively reviewed the literature on non-neoplastic indications for megaprosthesis of the proximal and distal femur after performing a detailed search of the Pubmed database using the medical subject heading (MeSH) terms ‘proximal femur replacement’ or ‘distal femur replacement’ and ‘hip or knee megaprosthesis.’ The data obtained after the structured search were entered into a Microsoft Excel spreadsheet. The frequency distribution of the demographic data, indications, complications, and outcome was calculated.

Result

We included ten studies (seven proximal femur replacement and three distal femur replacement) of 245 proximal femur and 54 distal femur mega prostheses for treatment of non-neoplastic conditions. Bone loss in failed arthroplasty, either due to periprosthetic fracture or deep infection, was the most common indication for megaprosthesis. Dislocation was the most common complication after proximal femur megaprosthesis, and infection was the leading cause of complications after distal femur megaprosthesis.

Conclusion

Megaprosthesis for treatment of non-neoplastic conditions around the distal and proximal femur is a viable option for limb salvage, with an acceptable long-term outcome. Although the complications and survival rates of megaprosthesis in non-neoplastic conditions are inferior to a primary arthroplasty of the hip and knee but are comparable or better than the mega prosthetic replacement in the neoplastic conditions. Proximal femoral megaprosthesis has higher dislocation rates and requirement for revision compared to distal femoral megaprosthesis. However, the proximal femoral megaprosthesis has lower rates of infection, periprosthetic fractures, and soft tissue complications, as compared to distal femoral megaprosthetic replacement. Both associated with aseptic loosening but not statistically significant.

The role of rotating hinge implants in revision total knee arthroplasty

Hinged implants are the most constrained knee replacement prostheses. They are very useful in complex cases of total knee arthroplasty (TKA) revision.

Hinged implants have evolved with rotating bearings and modularity that allows local joint reconstruction or segmental bone replacement.

They are required when significant instability persists in cases with inadequate collateral ligaments and significant flexion laxity.

They are now used when a large bone defect is reconstructed, or when bone fixation of the implant is questionable especially in the metaphyseal zone.

The use of hinged implants in TKA revision is associated with high complication rates. Published outcomes differ based on the patients’ aetiology.

The outcomes of rotating-hinged implants used in septic revisions or salvage situations are poorer than other types of revision and have a higher complication rate.

The poor general health of these patients is often a limitation.

Despite these relatively poor results, hinged implants continue to have a place in revision surgery to solve major instability or to obtain stable bone fixation of an implant when the metaphysis is filled with bone grafts or porous devices.

Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180070

Limb reconstruction after traumatic bone loss

A variety of options exist to reconstruct limbs following traumatic bone loss. The management of these injuries is challenging and often requires prolonged and potentially painful treatment. The Ilizarov technique of bone transport using circular external fixators is widely used for limb reconstruction of large bone defects. Other techniques include vascularised fibular grafting, the use of induced pseudosynovial membranes combined with cancellous autologous bone grafts and the use of autologous, allogeneic or synthetic bone grafts on their own for smaller defects. Future directions include further research on bone tissue engineering using stem cell therapy and growth factors such as bone morphogenetic proteins. The purpose of this Continuing Medical Education article is to describe the key limb reconstructive techniques that may be employed to treat traumatic bone loss. In particular, this article is intended to serve as a revision tool for those preparing for postgraduate examinations.

Length of Endoprosthetic Reconstruction in Revision Knee Arthroplasty Is Associated With Complications and Reoperations

BACKGROUND

Complex revision total knee arthroplasty (TKA) often calls for endoprosthetic reconstruction to address bone loss, poor bone quality, and soft tissue insufficiency. Larger amounts of segmental bone loss in the setting of joint replacement may be associated with greater areas of devascularized tissue, which could increase the risk of complications and worsen functional results.

QUESTIONS/PURPOSES

Are longer endoprosthetic reconstructions associated with (1) higher risk of deep infection; (2) increased risk of reoperation and decreased implant survivorship; or (3) poorer ambulatory status?

METHODS

This is a single-institution retrospective case series of nononcologic femoral endoprosthetic reconstructions for revision TKA from 1995 to 2013 (n = 32). Cases were categorized as distal (n = 17) or diaphyseal (n = 15) femoral reconstructions based on extension to or above the supracondylar metaphyseal-diaphyseal junction, respectively. Five patients from each group were lost to followup before 2 years (distal mean 4 years [range, 2-8 years]; diaphyseal mean = 6 years [range, 2-16 years]), and one of the 12 distal reconstructions and two of the 10 diaphyseal reconstructions had not been evaluated within the past 5 years. Clinical outcomes and ambulatory status (able to walk or not) were assessed through chart review by authors not involved in any cases. Prior incidence of periprosthetic joint infection was high in both groups (distal = seven of 12 versus diaphyseal = four of 10; p = 0.670).

RESULTS

Patients with diaphyseal femoral replacements were more likely to develop postoperative deep infections than patients with distal femoral replacements (distal = three of 12 versus diaphyseal = nine of 10; p = 0.004). Implant survivorship (revision-free) for diaphyseal reconstructions was worse at 2 years (distal = 100%, 95% confidence interval [CI], 100%-100% versus diaphyseal = 40%, 95% CI, 19%-86%; p = 0.001) and 5 years (distal = 90%, 95% CI, 75%-100% versus diaphyseal = 30%, 95% CI, 12%-73%; p = 0.001). Infection-free, revision-free survival (retention AND no infection) was worse for diaphyseal femoral replacing reconstructions than for distal femoral replacements at 2 years (distal = 70%, 95% CI, 48%-100% versus diaphyseal = 20%, 95% CI, 6%-69%; p = 0.037) and 5 years (distal = 70%, 95% CI, 48%-100% versus diaphyseal = 10%, 95% CI, 2%-64%; p = 0.012). There was no difference with the small numbers available in proportion of patients able to walk (distal reconstruction = eight of 11 versus diaphyseal = seven of 10; p = 1.000), although all but one patient in each group required walking aids.

CONCLUSIONS

Endoprosthetic femoral reconstruction is a viable salvage alternative to amputation for treatment of failed TKA with segmental distal femoral bone loss. In our small series even with substantial loss to followup and likely best-case estimates of success, extension proximal to the supracondylar metaphyseal-diaphyseal junction results in higher infection and revision risk. In infection, limb salvage remains possible with chronic antibiotic suppression, which we now use routinely for all femoral replacement extending into the diaphysis.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Modular Endoprostheses for Nonneoplastic Conditions: Midterm Complications and Survival

The use of modular endoprostheses is a viable option to manage both tumor resection and severe bone loss due to nonneoplastic conditions such as fracture sequelae, failed osteoarticular grafts, arthroplasty revisions, and periprosthetic fractures. We sought to investigate both midterm complications and failures occurred in 87 patients who underwent a megaprosthetic reconstruction in a nonneoplastic setting. After a mean follow-up of 58 (1–167) months, overall failure-free survival was 91.5% at 1 year, 80% at 2 years, 71.6% at 5 years, and 69.1% at 5 and 10 years. There was no significant difference in the survival rate according to the diagnosis at the index procedure (p = 0.921), nor to the reconstruction site (p = 0.402). The use of megaprostheses in a postneoplastic setting did not affect survival rate in comparison with endoprosthetic reconstruction of pure nonneoplastic conditions (p = 0.851). Perimegaprosthetic infection was the leading complication, occurring in 10 (11.5%) patients and implying a megaprosthetic revision in all but one case. Physicians should consider these results when discussing with patients desired outcomes of endoprosthetic reconstructions of a nonneoplastic disease.

Megaprostheses in the treatment of periprosthetic fractures of the knee joint: indication, technique, results and review of literature

BACKGROUND

Periprosthetic fractures (PPFs) after total knee arthroplasty (TKA), especially in patients with multiple revisions, remain challenging mainly due to bone quality and loss of bone stock. Megaprostheses, although providing immediate stability and weight bearing, are rarely used in this indication. The aim of the study was to provide a description of the surgical technique and evaluate the outcome of this technique with respectable published data.

MATERIALS AND METHODS

Systematic literature review revealed seven studies dealing with treating PPF after TKA using megaprostheses. Including the results of 11 cases treated in our institution between January 2008 and December 2014, 144 megaprostheses have been evaluated in the current literature with indication of PPF after TKA. Mean age at operation ranged from 68.4 to 81 years and mean follow-up from 6 to 58.6 months.

RESULTS

Revision rates after implantation of megaprostheses in PPFs ranged from 0 % (two studies with a mean follow-up of 6 and 33 months, respectively) to 55 %, all primarily performed for mechanical and nonmechanical failures (20 and 25, respectively). However infection was the most predominant reason for nonmechanical failure. Mortality rates ranged from 6.6 % after 1 year to 45 % after a mean follow-up of 34 months.

CONCLUSION

Megaprostheses represent a valuable option in distal femoral PPFs type 3 according to Su et al., as well as proximal tibia PPFs type 1B according to Felix et al., with loose tibial components. Infection remains the most frequent nonmechanical complication. Prospective clinical studies are required to exactly define the outcome of this technique in PPFs; use of the Henderson classification system would allow comparison between megaprostheses in oncological and nononcological indications.