Failure Analysis in Multiple TKA Revisions—Periprosthetic Infections Remain Surgeons’ Nemesis

Background: The aim of this study was to categorize reasons for failure and to analyze the survivorship of multiple total knee arthroplasty (TKA) revisions. Methods: The study retrospectively evaluated all multiple TKA revisions performed between 2005 and 2015 at the authors’ institutions. Sixty-three patients (35 female, 28 male, age 64 ± 10 years, follow-up 55 ± 36 months) underwent a total of 157 re-revision TKA surgeries (range 2–5). The revision indications were divided up into main diagnoses. Survivorship was evaluated by mixed model analysis. Results: The main overall reason for re-revision was periprosthetic joint infection (PJI) (48%), followed by instability (12%), polyethylene wear (11%), malpositioning (8%), and aseptic loosening (8%). Survivorship shortened with an increasing number of revision surgeries (p = 0.003). While PJI was in 38% of all cases, the reason for the first revision, incidence increased constantly with the number of revisions (48% at second revision, 55% at third revision, 86% at fourth revision, and 100% at fifth revision, p = 0.022). If periprosthetic infection caused the first revision, patients showed an average of two more septic revisions at follow-up than patients with an aseptic first revision indication (p < 0.001). In 36% of cases, the reason for follow-up surgery in case of periprosthetic infection was again PJI. Conclusion: The probability of survival of the implanted knee arthroplasty is significantly reduced with each subsequent revision. Periprosthetic infection is the main cause of multiple revisions.

Differences in mortality and complication rates following revision knee arthroplasty performed for urgent versus elective indications

Aims To compare rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision (urgent versus elective indications), and compare these with primary arthroplasty and re-revision arthroplasty. Methods Patients undergoing primary knee arthroplasty were identified in the national Hospital Episode Statistics (HES) between 1 April 1997 to 31 March 2017. Subsequent revision and re-revision arthroplasty procedures in the same patients and same knee were identified. The primary outcome was 90-day mortality and a logistic regression model was used to investigate factors associated with 90-day mortality and secondary adverse outcomes, including infection (undergoing surgery), pulmonary embolism, myocardial infarction, and stroke. Urgent indications for revision arthroplasty were defined as infection or fracture, and all other indications (e.g. loosening, instability, wear) were included in the elective indications cohort. Results A total of 939,021 primary knee arthroplasty procedures were included (939,021 patients), of which 40,854 underwent subsequent revision arthroplasty, and 9,100 underwent re-revision arthroplasty. Revision surgery for elective indications was associated with a 90-day rate of mortality of 0.44% (135/30,826; 95% confidence interval (CI) 0.37 to 0.52) which was comparable to primary knee arthroplasty (0.46%; 4,292/939,021; 95% CI 0.44 to 0.47). Revision arthroplasty for infection was associated with a much higher mortality of 2.04% (184/9037; 95% CI 1.75 to 2.35; odds ratio (OR) 3.54; 95% CI 2.81 to 4.46), as was revision for periprosthetic fracture at 5.25% (52/991; 95% CI 3.94 to 6.82; OR 6.23; 95% CI 4.39 to 8.85). Higher rates of pulmonary embolism, myocardial infarction, and stroke were also observed in the infection and fracture cohort. Conclusion Patients undergoing revision arthroplasty for urgent indications (infection or fracture) are at higher risk of mortality and serious adverse events in comparison to primary knee arthroplasty and revision arthroplasty for elective indications. These findings will be important for patient consent and shared decision-making and should inform service design for this patient cohort. Cite this article: Bone Joint J 2021;103-B(10):1578–1585.

Salvage of limb salvage in oncological reconstructions of the lower limb with megaprosthesis: how much to push the boundaries?

Introduction Megaprosthesis represent the most commonly used limb salvage method after musculoskeletal tumor resections. Nevertheless, they are burdened by high complication rate, requiring several surgical revisions and eventually limb amputation. The aims of this study were to evaluate the effect of rescuing the limb with subsequent revisions on complication rates (a), incidence of amputations (b), and whether complications reduce functional outcome after the first surgical revision (c). Materials and methods We retrospectively reviewed 444 lower limb megaprosthesis implanted for primary musculoskeletal tumors or metastatic lesions, from February 2000 to November 2017. 59 patients received at least one revision megaprosthesis surgery. MSTS score was used to assess final functional results. Complication-revision-amputation free survival rates were calculated both at 5 and 10 years of follow-up. Results Complication free survival, revision free survival and amputation free survival at 10 years were 47% and 53%, 61% and 67%, 90% and 86% among all 444 patients and the group of 59 revised patients, respectively. The incidence of further complications after the first complication was 26% in the group treated with no subsequent revision surgeries and 51% in the group with at least one revision surgery. We found a trend of inverse linear relationship between the number of complications needing subsequent revision surgeries and the final MSTS. Conclusion The number of further revision surgeries after limb salvage with megaprosthesis increases the incidence of complications. Repeated surgical revisions, in particular after infection, increase the amputation rate. The most frequent causes of failure were structural failures and infections. MSTS score was superior for patients undergoing limb salvage than amputees. However, MSTS progressively decreased with multiple revisions becoming inferior to the functional score of an amputated patient.

Diagnostic value of routine pre-operative investigations used in combination in the diagnosis of periprosthetic joint infection

The primary aim of this study was to assess the diagnostic accuracy of joint aspiration culture, serum C-reactive protein (CRP) and serum erythrocyte sedimentation rate (ESR), individually, and in combination for the diagnosis of periprosthetic joint infection (PJI). A consecutive patient series with pre-operative inflammatory marker levels, an aspiration culture of either hip or knee arthroplasty and intra-operative culture samples from subsequent revision surgery was compiled. This retrospective patient cohort analysis included 128 aspiration. The data were analysed to compare pre-operative aspiration cultures, serum ESR and CRP levels to the chosen gold standard for PJI diagnosis of intra-operative culture samples. A diagnostic algorithm was created using the above tests combined with clinical suspicion index. The values that had the highest sensitivity and specificity of predicting PJI were >5 for CRP and >16 for ESR. CRP used individually had the highest sensitivity and negative predictive value (NPV) of any test (75.0% and 75.9%, respectively). ESR + aspirate had the highest specificity and positive predictive value (PPV), of 100% for both. Using all three tests together the specificity and PPV were higher than the test individual values (95.3% and 85.0% respectively). Based on subgroup analyses the combination of ESR or CRP plus joint aspiration has superior PPV compared to individual tests. ESR and CRP had the highest NPV when used in isolation. An algorithm has been developed to guide clinical diagnosis.

Does the Duration of Primary and First Revision Surgery Influence the Probability of First and Subsequent Implant Failures after Extremity Sarcoma Resection and Megaprosthetic Reconstruction?

Complications in megaprosthetic reconstruction following sarcoma resection are quite common. While several risk factors for failure have been explored, there is a scarcity of studies investigating the effect of the duration of surgery. We performed a retrospective study of 568 sarcoma patients that underwent megaprosthetic reconstruction between 1993 and 2015. Differences in the length of surgery and implant survival were assessed with the Kaplan–Meier method, the log-rank test and multivariate Cox regressions using an optimal cut-off value determined by receiver operating curves analysis using Youden’s index. 230 patients developed a first and 112 patients a subsequent prosthetic failure. The median duration of initial surgery was 210 min. Patients who developed a first failure had a longer duration of the initial surgery (225 vs. 205 min, p = 0.0001). There were no differences in the probability of infection between patients with longer and shorter duration of initial surgery (12% vs. 13% at 5 years, p = 0.492); however, the probability of mechanical failure was higher in patients with longer initial surgery (38% vs. 23% at 5 years, p = 0.006). The median length of revision surgery for the first megaprosthetic failure was 101 min. Patients who underwent first revision for infection and did not develop a second failure had a longer median duration of the first revision surgery (150 min vs. 120 min, p = 0.016). A shorter length of the initial surgery appears beneficial, however, the notion that longer operating time increases the risk of deep infection could not be reproduced in our study. In revision surgery for infection, a longer operating time, possibly indicating a more thorough debridement, appears to be associated with a lower risk for subsequent revision.

710 A Novel Ventriculoperitoneal Shunt Design Aiming to Reduce Shunt Failure Rates

Introduction Ventriculoperitoneal (VP) shunt insertion is the most common surgical treatment for hydrocephalus. While shunt obstructions are frequent and subsequent revision operations carry significant morbidity, there is limited advancement in shunt design to address this problem. Method A literature review of aetiology and mechanism of shunt blockage was performed. Design concepts of current medical and non-medical grade devices were studied. Design improvements to VP shunt were focused on the proximal catheter and lumen configuration. Concept dimensions and computer flow simulations using different diameters were generated. Results An improved prototype VP shunt design was proposed. It has multiple lumens and communicating channels between neighbouring lumens to provide alternative routes for cerebrospinal fluid drainage in the event of individual lumen obstruction. Our design also features a novel cone-shaped proximal end to minimise occlusion by nearby choroid plexus. Conclusions By targeting common causes of VP shunt blockage through proposed novel design, the mean service-life of shunts can be extended, necessitating fewer revision procedures and reducing both patient health and financial burdens. Further investigation, optimisation, and validation of this proposed shunt design is required before further product development.

Mid-term foot function and pedobarographic analysis of 52 feet after polydactyly resection in childhood

Aims The aims of this study is to report the clinical and radiological outcomes after pre-, central-, and postaxial polydactyly resection in children from a tertiary referral centre. Methods All children who underwent resection of a supernumerary toe between 2001 and 2013 were prospectively enrolled and invited for a single re-assessment. Clinical parameters and several dedicated outcome scores (visual analogue scale (VAS), Paediatric Outcomes Data Collection Instrument (PODCI), Activities Scale for Kids (ASK), and American Orthopaedic Foot and Ankle Society Score (AOFAS)) were obtained, as were radiographs of the operated and non-operated feet along with pedobarographs. Results In all, 39 children (52 feet) with a mean follow-up of 7.2 years (3.1 to 13.0) were included in the study. Resection of a duplicated great toe was performed in ten children, central polydactyly in four, and postaxial polydactyly in 26. The mean postoperative VAS (0.7; 0 to 7), ASK (93.7; 64.2 to 100), and AOFAS range (85.9 to 89.0) indicated excellent outcomes among this cohort and the PODCI global functioning scale (95.7; 75.5 to 100) was satisfactory. No significant differences were found regarding outcomes of pre- versus postaxial patients, nor radiological toe alignment between the operated and non-operated sides. Minor complications were observed in six children (15%). There were seven surgical revisions (18%), six of whom were in preaxial patients. In both groups, below the operation area, a reduced mean and maximum force was observed. Changes in the hindfoot region were detected based on the prolonged contact time and reduced force in the preaxial group. Conclusion Excellent mid-term results can be expected after foot polydactyly resection in childhood. However, parents and those who care for these children need to be counselled regarding the higher risk of subsequent revision surgery in the preaxial patients. Also, within the study period, the plantar pressure distribution below the operated part of the foot did not return to completely normal. Cite this article: Bone Joint J 2021;103-B(2):415–420.