Aims Instability is a leading cause of revision after primary total knee arthroplasty (TKA). Isolated polyethylene exchange (IPE), typically involving increased insert thickness, is considered a fast and low-risk treatment option. However, evidence supporting its effectiveness remains limited. This study assesses outcomes and risk factors of IPE for secondary instability in unconstrained primary TKAs using data from the German Arthroplasty Registry (EPRD). Methods Patients with unconstrained primary TKA and subsequent IPE due to presumed instability were included. Polyethylene height increase served as a surrogate for instability severity. Cases with infection were excluded. Secondary patellar resurfacing (SPR) was analyzed as a potential influencing factor. Multivariate Cox regression and time-dependent analyses were used to identify predictors for re-revision, defined as any subsequent revision procedure. Results The study included 1,890 patients. IPE was performed on at a mean of 639 days (SD 521; 1 to 3343) after primary TKA, with a mean height increase of 3 mm (SD 2.2). The overall re-revision rate was 13.5%; 2.4% were due to periprosthetic joint infection. SPR was associated with lower revision risk (hazard ratio (HR) 0.50; 95% CI 0.37 to 0.68; p < 0.001). IPE one and two years after the index operation was associated with a decreased risk of subsequent revision (HR 0.33, 95% CI 0.20 to 0.55; HR 0.36, 95% CI 0.21 to 0.60). Polyethylene height increase > 3 mm was not associated with worse outcomes (< 3 mm HR 0.87, 95% CI 0.65 to 1.17; p = 0.358). Conclusion IPE can be a viable treatment for mild secondary instability following primary TKA, particularly with careful patient selection. SPR appears to improve implant survival and should be considered in cases with patellar pathology. Early-onset instability warrants critical evaluation, as it may indicate deeper underlying issues requiring component revision. These findings highlight the importance of an individualized surgical approach and underscore the need for thorough preoperative counselling to align treatment strategy with patient-specific risk factors and expectations.

Background: The use of augmented reality (AR) in orthopaedics is growing rapidly but is mainly limited to pre-operative planning and teaching. This study is one of the first to describe the intraoperative application within revision arthroplasty for the positioning of customised partial pelvic replacements. Methods: In a proof-of-concept study an AR environment was used during surgery in 11 cases to enhance implant positioning. Postoperatively, a voxel-based CT deviation analysis was carried out to determine the COR deviation and the cup plane deviation angle. Additionally, digital implant superimposition was conducted. Results: Implantation was possible in all cases with a mean COR deviation vector of 4.2 (SD 2.5; 1.2-9.3) mm and a cup plane deviation angle of 4.4 (SD 2.5; 0.7-8.1)°. The implant analysis showed a superimposition of 0.69 (SD 0.15; 0.38-0.88) (Dice-Score calculation). Conclusions: This study is able to report promising results for AR in orthopaedic surgery, showing improved intraoperative feedback in complex operations, resulting in increased accuracy. However, the integration of AR poses a new challenge to the surgical team, especially because the AR users are facing a significantly increased level of intraoperative stress. Further development of this auspicious tool, as well as a conceivable combination with navigation, is necessary to facilitate broader usage.

Aims:The aim of this study was to achieve consensus for important topics related to periprosthetic infection (PJI) in orthopaedic oncology, and to identify areas for future research. Methods:In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) held in Birmingham, UK, gathered 309 delegates from 53 countries to debate 20 consensus statements on PJI in orthopaedic oncology using a modified Delphi process. Results:Of 20 questions and statements on PJI in orthopaedic oncology, none achieved unanimous consensus, 18 achieved strong consensus, one achieved moderate consensus, and one achieved weak consensus. The statements that reached consensus with notable agreement were on the prophylaxis of infection, management of leaking wounds, and surgical strategies for the treatment of PJI. Short-duration antibiotic prophylaxis was deemed as effective as longer courses for lower-risk reconstructions, and aggressive management was recommended for wounds draining beyond five to seven days to prevent deep infection. Furthermore, single-stage, two-stage, and 1.5-stage revision were recognized as valid strategies, with two-stage revision remaining the most reliable. The statements that did not achieve consensus were on the role of debridement, antibiotics, and implant retention and prolonged antibiotic use post-revision. Conclusion:The BOOM meeting achieved consensus for important topics on periprosthetic infection in orthopaedic oncology, but highlighted the low quality of the underlying evidence. This study has provided recommendations for the treatment of leaky wounds, duration of postoperative antibiotic prophylaxis, and choice of revision strategy.

Aims:Following resection of a primary bone tumour, reconstruction is commonly performed using either a megaprosthesis or biological reconstruction. Periprosthetic joint infection (PJI) remains one of the most frequent complications. Various treatment strategies exist for PJI, including debridement, antibiotics, and implant retention (DAIR), and single- and two-stage revision, although consensus on optimal management remains elusive. This study aimed to investigate the global practices regarding DAIR in tumour cases through an electronic survey among orthopaedic oncology surgeons. Methods:A global cross-sectional observational survey study was distributed to 272 orthopaedic oncology surgeons who attended the BOOM Consensus Meeting in January 2024. The survey contained 19 multiple choice questions focusing on DAIR practices. Responses were collected anonymously and analyzed using descriptive statistics. Results:The survey was completed by 173/272 surgeons (64%) from 44 countries. While 62% (169/272) routinely performed radical soft-tissue debridement in DAIR, only 39% exchanged all modular components, indicating variability in surgical approaches. DAIR was more commonly performed in acute rather than chronic infections, with 55% finding it very useful in acute cases. The use of local antibiotic delivery was supported by 56%, although only 49% found antibiotic cement coatings beneficial. Systemic antibiotic duration post-DAIR varied, with 39% favouring six weeks and 35% preferring three months. Conclusion:The study highlights global inconsistencies in DAIR practices for PJI in orthopaedic oncology, with financial disparities impacting modular component exchange. Standardized definitions are lacking, and we propose that if only polyethylene is changed, then the procedure is referred to as 'poly exchange'; we recommend defining the procedure as DAIR when extensive debridement, lavage, and removal, wash, and reimplanting of all modular components is done while retaining stable stems, followed by suppressive antibiotic therapy; and finally, we recommend that if all the modular components are changed for new ones, the procedure is referred to as 'DAIR plus'.

The implantation of a tumour prosthesis for neoplastic indications can be considered to be a rare operation. After each tumour resection, the defect reconstruction plays a crucial role and always requires an individualised solution. In addition to modular tumour prostheses and growth prostheses for children, joint-preserving custom implants are being increasingly used. In most cases, the specific Diagnosis Related Groups (DRGs) I95A or I95B, which are available for tumour prostheses, are billed to the payers. The complex treatments require high professional expertise and are predominantly performed in specialised centres.This study addresses how these specialised services with various defect reconstructions achieve cost coverage within the modified DRG (aG-DRG) system in a university hospital centre.In this retrospective cost analysis, data from a university hospital were included for the period from mid-2021 to the end of 2023. The analysis considered case-related costs (personnel and material costs for surgery and on the ward, as well as service utilisation in functional areas). The actual costs were determined according to the current guidelines of the calculation manual issued by the German institute for the remuneration system in hospitals (InEK). As a result, each patient's internal hospital costs were compared with the respective cost blocks of the aG-DRG matrix.In total, 198 patients could be included, with an average age of 43.7 years (SD: 25.5), with a reduction of 2.7 days in the average length of stay compared to the duration specified by InEK.The cost-revenue analysis revealed an average undercoverage of € -1,223 per patient. The greatest discrepancy was found in the implant costs, with a hospital-specific undercoverage of € -1,445, primarily due to the location and the use of patient-specific implants. Both characteristics were identified as risk factors. The intensive care unit's costs and service utilisation in functional areas, particularly radiology and laboratory services, were lower in this patient group compared to the benchmark hospitals. These could almost compensate for the higher personnel costs of physicians - with a shortfall in both the operating theatre and on the normal ward.Despite its high specialisation, one of Germany's leading tumour orthopaedics centres is currently not reaching cost-coverage for the implantation of tumour prostheses. This is mainly due to the various types of bone defects that need to be treated following tumour resection. Surgeons are expected to achieve high functionality and limb preservation, which places significant demands on them. Each prosthesis implantation involves an individualised solution with varying costs for the implant. The current aG-DRG system does not adequately account for this individuality and the broad spectrum of a major centre. The introduction of flat fees for the availability of services will not improve the situation. A first step toward fairer compensation could be the implementation of a hospital-specific additional payment for custom implants.

Background/Objectives: The growing incidence of acetabular revisions has highlighted the importance of achieving reliable fixation to the remaining bone. Proximal transiliac fixation (TIF) of pelvic implants is becoming an increasingly common approach for managing extensive bone defects. This study seeks to provide guidance on TIF implantation by analyzing the optimal screw placement in partial pelvic replacements for acetabular defects. Methods: Between 2014 and 2024, a cohort of 96 consecutive patients (65 females and 31 males) who underwent customized partial pelvic replacement (PPR) with transiliac fixation (TIF) were examined. The angle and entry point of the ideal TIF were determined using preoperative three-dimensional planning and compared with potential influencing factors. Results: All PPRs were successfully implanted, with an average TIF length of 77 mm. The mean anteroposterior angle for TIF was 18° medially and 27° dorsally. Conclusions: Analysis of the entry point showed concentration around the second radius and between the eleven o’clock and one o’clock positions. The AP angle is notably affected by gender and height. Considering the precision of human judgment, a recommendation for TIF placement would be 20° medial and 30° dorsal deviation, with the entry point around the twelve o’clock position and the second ring from the center of the cup.

BACKGROUND:Off-the-shelf stems offer a wide variety of fixation methods for revision arthroplasty and intercalary tumour implants. However, in extensive defects or needed resection with minimal bone stock left, solid fixation is often not feasible with these implants. Custom-made stem solutions (CSS) offer a viable alternative in these cases to achieve joint preservation. METHODS:Between 2017 and 2024 14 patients (15 implants) were treated in a single-centre study. CSS were indicated if the remaining bone stock was deemed insufficient for normal stem fixation due to tumour resection or previous operations. Postoperative analysis was conducted to evaluate the functional outcome as well as revision rates. RESULTS:Implantation was possible in all cases, during the follow-up of 30 (SD 18; 6-66) months revision was needed in five cases; with one aseptic loosening, one screw loosening and three PJI cases. Mean MSTS score was 24 (SD 5; 17-30). CONCLUSION:Custom-made stem solutions show promising results in extreme cases. Especially as a preservation of the joint is possible, this treatment algorithm should be considered on a case-by-case basis.

Background and Objectives: Peri-acetabular metastases often lead to significant pain and functional impairment. Surgical interventions, including the Harrington procedure, aim to address these challenges. This study evaluates a modified Harrington procedure using the MUTARS® PRS® (Pelvic Revision Shell) with an 8 mm fixation screw for severe acetabular defects resulting from metastatic lesions. Materials and Methods: Retrospective analysis of 12 patients treated between January 2020 and December 2023 was conducted. The procedure involved using the novel MUTARS® PRS® with an 8 mm in diameter dome screw (length 70–100 mm). Outcome measures included implant positioning changes, complication rates, functional outcomes, implant longevity, and patient survival. Radiological assessments were performed postoperatively, with follow-ups at 3, 6, 12 months, and annually thereafter. Results: Average follow-up was 15 ± 11 months, with 67% patient survival at 1 year and 44% at 2 years. Implant survivorship remained 100%. Harris Hip Score improved significantly from 37 ± 22 preoperatively to 75 ± 15 at the last follow-up. No revisions involving implant components were reported. Complications occurred in 5 of 12 patients. Overall, PRS® demonstrates effective osseous ingrowth, high primary stability, immediate full weight-bearing, and low complication rates. Conclusions: PRS® integrates facilitating osseous ingrowth for preferable long-term outcomes, while efficiently transmitting the weight-bearing load to the intact aspect of the pelvis using a long 8 mm lever screw, enhancing the primary stability of the construct. It proves to be an effective and reproducible technique for managing destructive metastatic lesions of the acetabulum and peri-acetabular region, even in irradiated bone.

Aims Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction. Methods Between 2014 and 2023, 79 patients with a mean follow-up of 33 months (SD 22; 9 to 103) were included. Functional outcome was measured using the Harris Hip Score and EuroQol five-dimension questionnaire (EQ-5D). PPR revisions were defined as an endpoint, and subgroups were analyzed to determine risk factors. Results Implantation was possible in all cases with a 2D centre of rotation deviation of 10 mm (SD 5.8; 1 to 29). PPR revision was necessary in eight (10%) patients. HHS increased significantly from 33 to 72 postoperatively, with a mean increase of 39 points (p < 0.001). Postoperative EQ-5D score was 0.7 (SD 0.3;-0.3 to 1). Risk factor analysis showed significant revision rates for septic indications (p <= 0.001) as well as femoral defect size (p = 0.001). Conclusion Since large acetabular defects are being treated surgically more often, custom-made PPR should be integrated as an option in treatment algorithms. Monoflange PPR, with primary iliac fixation, offers a viable treatment option for Paprosky III defects with promising functional results, while requiring less soft-tissue exposure and allowing immediate full weightbearing.

Background: Improving local antibiotic delivery is a promising approach to improve infection control and potentially shorten systemic treatment in periprosthetic joint infection (PJI). This study investigates the use of an antibiotic-loaded, mouldable collagen-tricalciumphosphate composite in treatment of hip PJI. Methods: 124 application cases in 79 patients were included from a referral centre; systemic adverse infects, local complications, and infection control were analysed. Results: In most cases, either vancomycin or meropenem were used. Pathogens were previously known in 82 (66%) cases with polymicrobial infection in 20 (25%) patients. There were no cases of hypercalcaemia. Acute kidney injure was present in 14 (11%) cases. Chronic kidney failure persisted in two cases. During a mean follow-up of 12 (SD 9.3; range 3-35) months, implant survival was achieved in 73 (92%) patients; revision due to PJI was performed in 19 cases. Conclusion: Mouldable collagen-tricalciumphosphate composite bone substitute as a local antibiotic carrier in revision hip arthroplasty appears to be a valid option for local antibiotic delivery without systemic complications. Implant survival of 92% supports the hypothesis that local antibiotic therapy is an important component in the treatment of PJI.

Aims Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction. Methods Between 2014 and 2023, 79 patients with a mean follow-up of 33 months (SD 22; 9 to 103) were included. Functional outcome was measured using the Harris Hip Score and EuroQol five-dimension questionnaire (EQ-5D). PPR revisions were defined as an endpoint, and subgroups were analyzed to determine risk factors. Results Implantation was possible in all cases with a 2D centre of rotation deviation of 10 mm (SD 5.8; 1 to 29). PPR revision was necessary in eight (10%) patients. HHS increased significantly from 33 to 72 postoperatively, with a mean increase of 39 points (p < 0.001). Postoperative EQ-5D score was 0.7 (SD 0.3; -0.3 to 1). Risk factor analysis showed significant revision rates for septic indications (p ≤ 0.001) as well as femoral defect size (p = 0.001). Conclusion Since large acetabular defects are being treated surgically more often, custom-made PPR should be integrated as an option in treatment algorithms. Monoflange PPR, with primary iliac fixation, offers a viable treatment option for Paprosky III defects with promising functional results, while requiring less soft-tissue exposure and allowing immediate full weightbearing. Cite this article: Bone Jt Open 2024;5(8):688–696.

Zusammenfassung Die Verwendung von Megaendoprothesen in der Revisionsendoprothetik kann für komplexe Behandlungsfälle eine gute Behandlungsqualität liefern. Im Rahmen einer neoplastischen Indikation wird i. d. R. die Diagnosis Related Group (DRG) I95A mit einem Relativgewicht von 4,906 (2021) abgerechnet. Im Gegensatz dazu wird in der Revisionsendoprothetik, je nach Gelenkersatz, die entsprechende DRG angesteuert. Die Mehrkosten gegenüber der abgerechneten DRG sollen durch Vereinbarung krankenhausindividueller Zusatzentgelte ausgeglichen werden. Diese komplexen Operationen haben einen hohen fachlichen und operativen Anspruch und häufen sich überwiegend in spezialisierten Abteilungen. Wir haben in einer orthopädischen Fachklinik eine Kosten-Erlös-Analyse für den Einsatz der Megaendoprothese im Revisionsfall durchgeführt. Es soll die Frage beantwortet werden: Ist eine Kostendeckung im aG-DRG-System (aG-DRG: ausgegliederte German Diagnosis Related Groups) möglich? Es erfolgte eine retrospektive Analyse der Behandlungskosten. Im Zeitraum von 2018 bis 2020 wurden in der Fachklinik 113 Patienten mit einer Megaendoprothese nach aseptischer und septischer Revision einer Hüft- oder Knieprothese mit konsekutivem Knochendefekt behandelt und in die Studie eingeschlossen. Berücksichtigt wurden relevante fallbezogene Kostentreiber der aG-DRG-Matrix (u. a. Personal- und Sachkosten des OP-Bereichs und der Station). Die Ermittlung der Ist-Kosten erfolgte nach den Vorgaben des vom Institut für das Entgeltsystem im Krankenhaus (InEK) herausgegebenen Kalkulationshandbuches. Für jeden Patientenfall wurde der Deckungsbeitrag durch Relation der klinikinternen Kosten mit dem jeweiligen Kostenblock der angesteuerten aG-DRG-Matrix berechnet. Nach dem DRG-System 2021 kamen 17 verschiedene DRGs zur Abrechnung, dem ein patientenbezogener Gesamtschweregrad (PCCL) von 70% ≥ 4 zugrunde lag. Verglichen mit der InEK-Kalkulation kommt es zu einer Unterdeckung in den untersuchten Bereichen von 2901 € je Patientenfall. Die Personalkosten des ärztlichen Dienstes zeigen eine Unterdeckung sowohl im Kostenstellenbereich OP als auch Station. Die Implantatkosten zeigen eine klinikspezifische Unterdeckung von −2181 €. Bei der Analyse der Risikofaktoren auf die Kostendeckung wiesen nur diese einen signifikanten Unterschied auf. Die Implantation der Megaprothese im Revisionsfall stellt häufig die letzte Option zum Erhalt der Extremitätenfunktion dar. Gegenwärtig ist diese Leistung in der orthopädischen Fachklinik nicht kostendeckend zu erbringen, trotz einer hohen Spezialisierung und Prozessoptimierung. Die von der Politik gewünschte Spezialisierung der Kliniken setzt eine ausreichende Vergütung komplexer Behandlungsfälle voraus. Das wirtschaftliche Ergebnis jedes Behandlungsfalles ist mit einem Risiko behaftet, das nicht vorhergesagt werden kann. Im Gegenzug wird der Revisionschirurg mit diesen Patienten konfrontiert und muss sie behandeln. Die hohe Standardabweichung weist auf große Unterschiede der Kosten-Erlös-Situation jedes einzelnen Falles hin. Unser Ergebnis zeigt erstmals eine realistische Kostenbetrachtung für die Megaprothese im Revisionsfall und unterstreicht, wie wichtig ein adäquat mit den Kostenträgern vereinbartes krankenhausindividuelles Zusatzentgelt ist. In die Kalkulation sollten nicht nur die Implantatkosten, sondern auch die höheren Personalkosten (erhöhter Planungsaufwand, Qualitätssicherungskonferenzen, OP-Zeit etc.) einfließen.

Zusammenfassung Die Planung und Implantation eines individuellen Beckenteilersatzes stellt hohe Anforderungen sowohl an den Operateur als auch an das gesamte Team (Ingenieur, Assistenten, Operationsteam). Durch die sorgfältige präoperative Planung sowie die stringente intraoperative Durchführung stellt der individuelle Beckenteilersatz ein aufwendiges, aber zuverlässig anwendbares Verfahren zur Defektrekonstruktion auch hochkomplexer azetabulärer Knochendefekte dar, auch nach multiplen Voroperationen.

Supra-acetabular bone loss close beyond the sciatic notch is one of the most challenging defect types for stable anatomical reconstruction in revision arthroplasty. Using reconstruction strategies from tumour orthopaedic surgery, we adapted tricortical trans-iliosacral fixation options for custom-made implants in revision arthroplasty. The aim of the present study was to present the clinical and radiological results of this extraordinary pelvic defect reconstruction. Between 2016 and 2021, 10 patients with a custom-made pelvic construct using tricortical iliosacral fixation (see Fig. 1) were included in the study. Follow-up was 34 (SD 10; range 15–49) months. Postoperatively CT scans evaluating the implant position were performed. Functional outcome and the clinical results were recorded. Implantation was possible as planned in all cases in 236 (SD 64: range 170–378) min. Correct centre of rotation (COR) reconstruction was possible in nine cases. One sacrum screw crossed a neuroforamen in one case without clinical symptoms. During the follow-up period, four further operations were required in two patients. There were no individual implant revisions or aseptic loosening recorded. The Harris Hip Score increased significantly from 27 Pts. to 67 Pts. with a mean improvement of 37 (p < 0.005). EQ-5D developed from 0.562 to 0.725 (p = 0.038) as a clear improvement in quality of life. Custom-made partial pelvis replacement with iliosacral fixation offers a safe solution in “beyond Paprosky type III defects” for hip revision arthroplasty. Due to meticulous planning, precise implantation with good clinical outcome can be achieved. Furthermore, the functional outcome and patient satisfaction increased significantly showing promising early results with a relatively low complication rate.

Background: While off-the-shelf cones and sleeves yield good results in AORI type 2 and 3 defects in revision knee surgery, massive longitudinal defects may require a proximal tibia replacement. To achieve the best anatomical as well as biomechanical reconstruction and preserve the tibial tuberosity, we developed custom-made metaphyseal sleeves (CMSs) to reconstruct massive defects with a hinge knee replacement. Methods: Between 2019 and 2022, 10 patients were treated in a single-center study. The indication for revision was aseptic loosening in five cases and periprosthetic joint infection in five cases. The mean number of previous revisions after the index operations was 7 (SD: 2; 4–12). A postoperative analysis was conducted to evaluate the functional outcome as well as the osteointegrative potential. Results: Implantation of the CMS in rTKA was carried out in all cases, with a mean operation time of 155 ± 48 (108–256) min. During the follow-up of 23 ± 7 (7–31) months, no CMS was revised and revisions due to other causes were conducted in five cases. Early radiographic evidence of osseointegration was recorded using a validated method. The postoperative OKS showed a significant increase (p < 0.001), with a mean score of 24 (SD: 4; range: 14–31). Conclusion: Custom-made metaphyseal sleeves show acceptable results in extreme cases. As custom-made components become more and more common, this treatment algorithm presents a viable alternative in complex rTKA.

IntroductionMegaendoprosthesis offer a viable treatment in complex revision arthroplasty cases with good functional outcome. In the context of a neoplastic indication, the diagnosis-related group (DRG) I95A is usually assigned with a relative weight of 4.906 (2021). In contrast, in revision arthroplasty, the appropriate DRG is assigned, depending on the joint replacement. The additional costs compared to the invoiced DRG are to be compensated by agreeing on hospital-specific individual fees. These complex revision arthroplasties set high technical and operative demands and are mainly performed in specialised departments. We conducted a cost-benefit analysis of the use of the megaendoprosthesis in revision cases in a specialised orthopaedic clinic, as a single centre study. The question we sought to answer was: Is cost recovery possible in the modified German DRG system (aG-DRG)?Materials and MethodsA retrospective single centre analysis of treatment costs was performed. From 2018 to 2020, 113 patients treated with a megaendoprosthesis reconstruction in a referral centre due to extensive bone loss after aseptic or septic revision of a hip or knee prosthesis were included in the study. Relevant case-related cost drivers of the aG-DRG matrix (including staff and material costs of the operating theatre area and the ward) were taken into account. The actual costs were determined according to the specifications of the calculation manual published by the German institute for the remuneration system in hospitals (InEK). For each case, the contribution margin was calculated by relating the hospital's internal costs to the corresponding cost pool of the aG-DRG matrix.ResultsAccording to the DRG system 2021, 17 different DRGs were used for billing - in 70% based on a patient clinical complexity level (PCCL) >= 4. Compared with the InEK calculation, there is a deficit of -2,901 (sic) per case in the examined parameters. The costs of physicians show a shortfall in both the operating theatre and on the ward. Implant costs, which were supposed to be compensated by hospital-specific additional charges, show a hospital-specific shortage of -2,181 (sic). When analysing the risk factors for cost recovery, only these showed a significant difference.ConclusionImplantation of the megaendoprosthesis in revision arthroplasty is often the last option to preserve limb function. At present, despite a high degree of specialisation and process optimisation, this treatment cannot be provided cost-effectively even in tertiary care. The politically desired specialised department structure requires sufficient reimbursement for complex cases. The economic outcome of each treatment case is often unpredictable, however the surgeon is confronted with these cases and is expected to treat them. The high standard deviation indicates large differences in the cost/revenue situation of each individual case. Our results show for the first time a realistic cost analysis for megaprosthesis in revision arthroplasty and underline the importance of an adequate hospital-specific charge, individually agreed by the funding units. The calculation should include not only the implant costs, but also the increased staff costs (increased, complex planning effort, quality management, surgery time, etc.).

AIMS The aim of this study was to examine the implant accuracy of custom-made partial pelvis replacements (PPRs) in revision total hip arthroplasty (rTHA). Custom-made implants offer an option to achieve a reconstruction in cases with severe acetabular bone loss. By analyzing implant deviation in CT and radiograph imaging and correlating early clinical complications, we aimed to optimize the usage of custom-made implants. METHODS A consecutive series of 45 (2014 to 2019) PPRs for Paprosky III defects at rTHA were analyzed comparing the preoperative planning CT scans used to manufacture the implants with postoperative CT scans and radiographs. The anteversion (AV), inclination (IC), deviation from the preoperatively planned implant position, and deviation of the centre of rotation (COR) were explored. Early postoperative complications were recorded, and factors for malpositioning were sought. The mean follow-up was 30 months (SD 19; 6 to 74), with four patients lost to follow-up. RESULTS Mean CT defined discrepancy (Δ) between planned and achieved AV and IC was 4.5° (SD 3°; 0° to 12°) and 4° (SD 3.5°; 1° to 12°), respectively. Malpositioning (Δ > 10°) occurred in five hips (10.6%). Native COR reconstruction was planned in 42 cases (93%), and the mean 3D deviation vector was 15.5 mm (SD 8.5; 4 to 35). There was no significant influence in malpositioning found for femoral stem retention, surgical approach, or fixation method. CONCLUSION At short-term follow-up, we found that PPR offers a viable solution for rTHA in cases with massive acetabular bone loss, as highly accurate positioning can be accomplished with meticulous planning, achieving anatomical reconstruction. Accuracy of achieved placement contributed to reduced complications with no injury to vital structures by screw fixation.Cite this article: Bone Joint J 2022;104-B(10):1110-1117.

BACKGROUND:External quality assurance for revisions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) are carried out through the AQUA institute in Germany. Data are collected by the providers and are analyzed based on predefined quality indicators from the hospital stay in which the revision was performed. The present study explores the possibility to add routine data analysis to the existing external quality assurance (EQS). Differences between methods are displayed. The study aims to quantify the benefit of an additional analysis that allows patients to be followed up beyond the hospitalization itself.MATERIAL AND METHODS:All persons insured in an AOK sickness fund formed the population for analysis. Revisions were identified using the same algorithm as the existing external quality assurance. Adverse events were defined according to the AQUA indicators for the years 2008 to 2011.The hospital stay in which the revision took place and a follow-up of 30 days were included. For re-operation and dislocation we also defined a 365 days interval for additional follow-up. The results were compared to the external quality control reports.RESULTS:Almost all indicators showed higher events in claims data analysis than in external quality control. Major differences are seen for dislocation (EQS SD: 1.87 vs. claims data [cd] SD: 2.06 %, cd+30 d: 2.91 %, cd+365 d: 7.27 %) and reoperation (hip revision: EQS SD: 5.88 % vs. claims data SD: 8.79 % cd+30 d: 9.82 %, cd+365 d: 15.0 %/knee revision: EQS SD: 3.21 % vs. claims data SD: 4.07 %, cd+30 d: 4.6 %, cd+365 d: 15.43 %). Claims data could show additional adverse events for all indicators after the initial hospital stay, rising to 77 % of all events.CONCLUSIONS:The number of adverse events differs between the existing external quality control and our claims data analysis. Claims data give the opportunity to complement existing methods of quality control though a longer follow-up, when many complications become evident.

External quality assurance for revisions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) are carried out through the AQUA institute in Germany. Data are collected by the providers and are analyzed based on predefined quality indicators from the hospital stay in which the revision was performed. The present study explores the possibility to add routine data analysis to the existing external quality assurance (EQS). Differences between methods are displayed. The study aims to quantify the benefit of an additional analysis that allows patients to be followed up beyond the hospitalization itself.All persons insured in an AOK sickness fund formed the population for analysis. Revisions were identified using the same algorithm as the existing external quality assurance. Adverse events were defined according to the AQUA indicators for the years 2008 to 2011.The hospital stay in which the revision took place and a follow-up of 30 days were included. For re-operation and dislocation we also defined a 365 days interval for additional follow-up. The results were compared to the external quality control reports.Almost all indicators showed higher events in claims data analysis than in external quality control. Major differences are seen for dislocation (EQS SD: 1.87 vs. claims data [cd] SD: 2.06 %, cd+30 d: 2.91 %, cd+365 d: 7.27 %) and reoperation (hip revision: EQS SD: 5.88 % vs. claims data SD: 8.79 % cd+30 d: 9.82 %, cd+365 d: 15.0 %/knee revision: EQS SD: 3.21 % vs. claims data SD: 4.07 %, cd+30 d: 4.6 %, cd+365 d: 15.43 %). Claims data could show additional adverse events for all indicators after the initial hospital stay, rising to 77 % of all events.The number of adverse events differs between the existing external quality control and our claims data analysis. Claims data give the opportunity to complement existing methods of quality control though a longer follow-up, when many complications become evident.

We evaluated the clinical results and complications after extra-articular resection of the distal femur and/or proximal tibia and reconstruction with a tumour endoprosthesis (MUTARS) in 59 patients (mean age 33 years (11 to 74)) with malignant bone or soft-tissue tumours. According to a Kaplan-Meier analysis, limb survival was 76% (95% confidence interval (CI) 64.1 to 88.5) after a mean follow-up of 4.7 years (one month to 17 years). Peri-prosthetic infection was the most common indication for subsequent amputation (eight patients). Survival of the prosthesis without revision was 48% (95% CI 34.8 to 62.0) at two years and 25% (95% CI 11.1 to 39.9) at five years post-operatively. Failure of the prosthesis was due to deep infection in 22 patients (37%), aseptic loosening in ten patients (17%), and peri-prosthetic fracture in six patients (10%). Wear of the bearings made a minor revision necessary in 12 patients (20%). The mean Musculoskeletal Tumor Society score was 23 (10 to 29). An extensor lag > 10° was noted in ten patients (17%). These results suggest that limb salvage after extra-articular resection with a tumour prosthesis can achieve good functional results in most patients, although the rates of complications and subsequent amputation are higher than in patients treated with intra-articular resection.