Aim. Acute post-surgical infection is one of the most serious complications after instrumented thoracolumbar fusion with an incidence of 0.7%-12%. Acute infection can lead to an increase in morbidity, mortality, and economic costs for the healthcare system. The main objective of our study was to determine the variables associated with a higher risk of acute infection after thoracolumbar instrumentation in our center. Methods. We conducted an observational case-control study including instrumented fusions of the thoracolumbar spine performed between 2015 and 2021 at our institution. We included patients with thoracolumbar fusions after a fracture or for the treatment of degenerative pathology. We analyzed demographic variables related to the surgical procedure, the causative microorganism of infection, the outcome of infection treatment, and complications. We performed a descriptive analysis of all variables and a univariate comparison of cases and controls. The dichotomous variables were compared using the Fisher test, while the quantitative variables were compared using the Student's T-test. A p-value of <0.05 is taken into account to consider the statistical significance. SPSS v25 Windows program was used for statistical analyses. Results. 455 patients were included, 53% were male with a mean age of 60 years. 35% of patients had a BMI (Body Mass Index) >30, 21.1% were classified as ASA (American Society of Anesthesiologists) >3, 15.8% were diabetic, and 2.6% were under chronic corticosteroid treatment. In 34.1% of the fusions, the procedure lasted more than 3 hours. We identified 26 post-surgical acute infections (5.7%). Patients with an infection had a higher prevalence of diabetes (14.7% vs 34.6% p=0.012), chronic corticosteroid treatment (2.1% vs 11.5% p=0.026), and a higher percentage of surgeries with duration > 3 hours (32.4% vs. 61.1%, p=0.019). A trend towards significance was also observed in patients classified as ASA >3 (20.3% vs. 34.6%, p=0.088), and BMI >30 (33.8% vs. 53.8%, p=0.054). No significant differences were observed in the rest of the variables studied. The most frequent causative microorganism was S.epidermidis (38%), followed by S.aureus (34%) and polymicrobial infections (34%). Conclusions. There is a significant increase in infection in diabetic patients, patients with chronic corticosteroid treatment, and in surgeries lasting > 3 hours

Hip resurfacing may be a useful surgical procedure when patient selection is correct and only implants with superior performance are used. In order to establish a body of evidence in relation to hip resurfacing, pseudotumour formation and its genetic predisposition, we performed a case-control study investigating the role of HLA genotype in the development of pseudotumour around MoM hip resurfacings. All metal-on-metal (MoM) hip resurfacings performed in the history of the institution were assessed. A total of 392 hip resurfacings were performed by 12 surgeons between February 1st 2005 and October 31st 2007. In all cases, pseudotumour was confirmed in the preoperative setting on Metal Artefact Reduction Sequencing (MARS) MRI. Controls were matched by implant (ASR or BHR) and absence of pseudotumour was confirmed on MRI. Blood samples from all cases and controls underwent genetic analysis using Next Generation Sequencing (NGS) assessing for the following alleles of 11 HLA loci (A, B, C, DRB1, DRB3/4/5, DQA1, DQB1, DPB1, DPA1). Statistical significance was determined using a Fisher's exact test or Chi-Squared test given the small sample size to quantify the clinical association between HLA genotype and the need for revision surgery due to pseudotumour. Both groups were matched for implant type (55% ASR, 45% BHR in both the case and control groups). According to the ALVAL histological classification described by Kurmis et al., the majority of cases (63%, n=10) were found to have group 2 histological findings. Four cases (25%) had group 3 histological findings and 2 (12%) patients had group 4 findings. Of the 11 HLA loci analysed, 2 were significantly associated with a higher risk of pseudotumour formation (DQB1*05:03:01 and DRB1*14:54:01) and 4 were noted to be protective against pseudotumour formation (DQA1*03:01:01, DRB1*04:04:01, C*01:02:01, B*27:05:02). These findings further develop the knowledge base around specific HLA genotypes and their role in the development of pseudotumour formation in MoM hip resurfacing. Specifically, the two alleles at higher risk of pseudotumour formation (DQB1*05:03:01 and DRB1*14:54:01) in MoM hip resurfacing should be noted, particularly as patient-specific genotype-dependent surgical treatments continue to develop in the future

Proximal femur fractures are increasing in prevalence, with femoral neck (FN) and intertrochanteric (IT) fractures representing the majority of these injuries. The salvage procedure for failed open reduction internal fixation (ORIF) is often a conversion to total hip arthroplasty (THA). The use of THA for failed ORIF improves pain and function, however the procedure is more challenging. The aim of this study was to investigate the clinical and radiographic outcomes in patients who have undergone THA after ORIF. This retrospective case-control study compared patients who underwent THA after failed ORIF to a matched cohort undergoing primary THA for non-traumatic osteoarthritis. From 2004 to 2014, 40 patients were identified. The matched cohort was matched for date of operation, age, gender, and type of implant. Preoperative, intraoperative, and postoperative data were collected and statistical analysis was performed. The cohort of patients with a salvage THA included 18 male and 22 female patients with a mean age of 73 years and mean follow up of 3.1 years. Those with failed fixation included 12 IT fractures and 28 FN fractures. The mean time between ORIF and THA was 2.1 years for IT fractures and 8.5 years for FN fractures (p=0.03). The failed fixation group had longer procedures, greater drop in hemoglobin, and greater blood transfusion rate (p<0.05). There was one revision and one dislocation in the failed fixation group with no revisions or dislocations in the primary THA group. Length of admission, medical complications, and functional outcome as assessed with a standardised hip score and were found not to be statistically different between the groups. Salvage THA for failed initial fixation of proximal femur fractures yields comparable clinical results to primary THA with an increased operative time, blood loss, and blood transfusion rate

Aim

Mega-endoprosthesis over the last two decades have played a significant role in management of non-neoplastic cases for limb salvage for a variety of indications involving bone loss, infection, fracture and failed revision surgery. This is a retrospective case control study comparing outcomes of Mega-Endoprosthesis (MEP) in non-neoplastic cases with periprosthetic joint infections (PJI), with previous history of PJI and aseptic revision. Failure was defined as persistence/recurrence of infection, all cause revision, and antibiotic suppression during the follow up period. Secondary aims were identification of causative organisms, resistance profile and causative factors for revision surgery.

Osteoarthritis (OA) is a disease of the synovial joint with synovial inflammation, capsular contracture, articular cartilage degradation, subchondral sclerosis and osteophyte formation contributing to pain and disability. Transcriptomic datasets have identified genetic loci in hip and knee OA demonstrating joint specificity. A limited number of studies have directly investigated transcriptional changes in shoulder OA. Further, gene expression patterns of periarticular tissues in OA have not been thoroughly investigated. This prospective case control series details transcriptomic expression of shoulder OA by analysing periarticular tissues in patients undergoing shoulder replacement for OA as correlated with a validated patient reported outcome measure of shoulder function, an increasing (clinically worsening) QuickDASH score. We then compared transcriptomic expression profiles in capsular tissue biopsies from the OA group (N=6) as compared to patients undergoing shoulder stabilisation for recurrent instability (the control group, N=26). Results indicated that top ranked genes associated with increasing QuickDASH score across all tissues involved inflammation and response to stress, namely interleukins, chemokines, complement components, nuclear response factors and immediate early response genes. Some of these genes were upregulated, and some downregulated, suggestive of a state of flux between inflammatory and anti-inflammatory signalling pathways. We have also described gene expression pathways in shoulder OA not previously identified in hip and knee OA, as well as novel genes involved in shoulder OA.

Background

Polymethylmethacrylate (PMMA) has been used for total knee arthroplasty (TKA) as a method of fixation; however, its durability has been questionable for the long-term use because of the loosening after the cement deterioration, its vulnerability toward infectious resistance, and a smaller amount of healthy bone left for the knee revision surgery. Especially, a decrease of bone density on the proximal tibia has been believed to be triggered as a result of stress shielding. When compared with a cemented TKA, a cementless TKA reduces the amount of bone loss after surgery. In 1999, the Trabecular Metal (TM), with its main composition being the porous tantalum metal, became available as a choice of the porous cementless knee joint prosthesis. The characteristics of porous tantalum metal are its great affinity to the bone as well as its similarity to cancellous bone. The porous tantalum metal starts to bond with osteoblasts, and fills up 80% of porous structure in one year; therefore, it has been characterized by its higher initial fixation strength. However, it is questionable if strong fixation strength due to bone ingrowth between the tibial tray mainly made up with the porous tantalum metal and a cancellous bone will continually be kept. Bobyn, JD, Dunbar et al. have acknowledged the existence of bone ingrowth based on the radiographic evaluation; however, their data had not been quantified in their report. In this study, the bone ingrowth density have periodically quantified using 3D bone morphometric software (TRI/3D-BON64.RATOC) after taking CT of the knee joint prosthesis.

BACKGROUND

Periprosthetic infection is the most challenging complication following total knee arthroplasty (TKA). Poor oral hygiene has been assumed as an important risk factor for TKA infection. We aimed to investigate whether the improvement of oral hygiene through dental scaling could reduce the risk of TKA infection.

Surgical site infections following orthopaedic surgery are a serious complication associated with increased morbidity and mortality. Intra-wound antibiotic powder may be able to provide infection prophylaxis locally with less systemic adverse effects, and promising results have been reported in systematic reviews of its use in spine surgery. This study aims to analyse the efficacy and adverse effect profile of intra-wound antibiotics in reducing surgical site infections in orthopaedic surgery for traumatic pelvic and lower limb fractures. A systematic review was conducted for studies reporting on the incidence of surgical site infections following administration of intra-wound antibiotic powder in pelvic and lower limb trauma surgery. Randomised controlled trials, cohort and case-control studies were included. A meta-analysis was conducted for deep surgical site infections. Seven studies were included in the systematic review including six retrospective case-control studies and one randomised controlled trial. Results of the meta-analysis suggest a potential 23% reduction in the odds of developing a deep surgical site infection in patients treated with intra-operative antibiotic powder compared with those managed with intravenous antibiotics alone (OR 0.77, 95% CI 0.52 – 1.13), although the results did not reach statistical significance. Notable selective bias against intra-wound antibiotics and suboptimal study design were found in the retrospective studies, however the randomised controlled trial reported a significant reduction in deep surgical site infections with intra-wound vancomycin powder. There were no reports of systemic adverse outcomes and minimal risk of wound complications with the use of intra-wound antibiotics. This review suggests the use of intra-wound antibiotic powder in pelvic and lower limb trauma surgery may reduce the incidence of deep surgical site infections. Further powered studies including randomised controlled trials are required to confirm the results highlighted in this study

Aims. Global literature suggests that female surgical trainees have lower rates of independent operating (operative autonomy) than their male counterparts. The objective of this study was to identify any association between gender and lead/independent operating in speciality orthopaedic trainees within the UK national training programme. Methods. This was a retrospective case-control study using electronic surgical logbook data from 2009 to 2021 for 274 UK orthopaedic trainees. Total operative numbers and level of supervision were compared between male and female trainees, with correction for less than full-time training (LTFT), prior experience, and time out during training (OOP). The primary outcome was the percentage of cases undertaken as lead surgeon (supervised and unsupervised) by UK orthopaedic trainees by gender. Results. All participants gave permission for their data to be used. In total, 274 UK orthopaedic trainees submitted data (65% men (n = 177) and 33% women (n = 91)), with a total of 285,915 surgical procedures logged over 1,364 trainee-years. Males were lead surgeon (under supervision) on 3% more cases than females (61% (115,948/189,378) to 58% (50,285/86,375), respectively; p < 0.001), and independent operator (unsupervised) on 1% more cases. A similar trend of higher operative numbers in male trainees was seen for senior (ST6 to 8) trainees (+5% and +1%; p < 0.001), those with no time OOP (+6% and +8%; p < 0.001), and those with orthopaedic experience prior to orthopaedic specialty training (+7% and +3% for lead surgeon and independent operator, respectively; p < 0.001). The gender difference was less marked for those on LTFT training, those who took time OOP, and those with no prior orthopaedic experience. Conclusion. This study showed that males perform 3% more cases as the lead surgeon than females during UK orthopaedic training (p < 0.001). This may be due to differences in how cases are recorded, but must engender further research to ensure that all surgeons are treated equitably during their training. Cite this article: Bone Joint J 2023;105-B(7):821–832

Surgical site infections (SSIs) after spinal fusion surgery increase healthcare costs, morbidity and mortality. Routine measures of obesity fail to consider site specific fat distribution. We aimed to assess the association between the spine adipose index and deep surgical site infection and determine a threshold value for spine adipose index that can assist in preoperative risk stratification in patients undergoing posterior instrumented lumbar fusion (PILF). A multicentre retrospective case-control study was completed. We reviewed patients who underwent PILF from January 1, 2010 to December 31, 2018. All patients developing a deep primary incisional or organ-space SSI within 90 days of surgery as per US Centre for Disease Control and Prevention criteria were identified. We gathered potential pre-operative and intra-operative deep infection risk factors for each patient. Spine adipose index was measured on pre-operative mid-sagittal cuts of T2 weighted MRI scans. Each measurement was repeated twice by three authors in a blinded fashion, with each series of measurement separated by a period of at least six weeks. Forty-two patients were included in final analysis, with twenty-one cases and twenty-one matched controls. The spine adipose index was significantly greater in patients developing deep SSI (p =0.029), and this relationship was maintained after adjusting for confounders (p=0.046). Risk of developing deep SSI following PILF surgery was increased 2.0-fold when the spine adipose index was ≥0.51. The spine adipose index had excellent (ICC >0.9; p <0.001) inter- and intra-observer reliabilities. The spine adipose index is a novel radiographic measure and an independent risk factor for developing deep SSI, with 0.51 being the ideal threshold value for pre-operative risk stratification in patients undergoing PILF surgery

PFFs are an increasing burden presenting to the acute trauma services. The purpose of this study is to show that cemented revision for Vancouver B2/B3 PFFs is a safe option in the geriatric population, allows early pain-free weight bearing and comparable to a control-group of uncemented stems with regard to return to theatre and revision surgery. A retrospective review was conducted of all PFFs treated in a Level 1 trauma centre from 2015-2020. Follow up x-rays and clinical course through electronic chart was reviewed for 78 cemented revisions and 49 uncemented revisions for PFF. Primary endpoints were all cause revision and return to theatre for any reason. Secondary endpoints recorded mobility status and all-cause mortality. In the cemented group there were 73 Vancouver B2, 5 Vancouver B3 PFF; the mean age was 79.7 years and mean radiological follow-up of 11.9 months. In the cementless group there were 32 Vancouver B2 and 17 Vancouver B3 PFFs; with all 49 patients undergoing distally bearing uncemented revision, the mean age was 72.7 years and mean radiological follow-up of 21.3 months. Patients treated with a cemented prosthesis had significantly higher ASA score (2.94 -v- 2.43, p<0.001). The primary endpoints showed that there was no significant difference in all cause revision 3/78 and 5/49 p=0.077, or return to theatre 13/78 -v- 12/49 p=0.142. Secondary endpoints revealed no significant difference in in-hospital mortality. The cementless group were more likely to be mobilising without any aid at latest follow-up 35/49 -v- 24/78 p<0.001. The use of cemented revision femoral component in the setting of PFFs is one option in the algorithm for management of unstable PFFs according to the Vancouver classification. Evidence from this case-control study, shows that the all-cause revision and return to theatre for any cause was comparable in both groups

This study aimed to identify factors associated with increased rates of blood transfusion in patients with adolescent idiopathic scoliosis (AIS) treated with posterior spinal fusion (PSF). A retrospective case-control study was performed for AIS patients treated at a large children's hospital between August 2018 and December 2020. All patients with a diagnosis of AIS were evaluated. Data on patient demographics, AIS, and transfusion parameters were collected. Univariate regression and multivariate logistic modeling were utilized to assess risk factors associated with requiring transfusion. Odds ratios (OR) and 95% confidence interval (CI) were calculated. Surgeries were done by three surgeons and thirty anesthesiologists. To quantify the influence of anesthesia practice preferences a categorical variable was defined as “higher-transfusion practice preference”, for the provider with the highest rate of transfusion. A total of 157 AIS patients were included, of whom 56 were transfused RBC units (cases), and 101 did not receive any RBC transfusion (controls). On univariate analysis, the following variables were significantly correlated with receiving RBC transfusion: “higher-transfusion practice preference,” “administration of crystalloids,” “receiving fresh frozen plasma (FFP),” “receiving platelets,” “pre-operative hemoglobin,” “cell saver volume,” and “surgical time.” On multiple regression modeling, “pre-operative hemoglobin less than 120 g/L” (OR 14.05, 95% CI: 1.951 to 135.7) and “higher-transfusion practice preference” (OR 11.84, 95% CI: 2.505 to 63.65) were found to be meaningfully and significantly predictive of RBC transfusion. In this cohort, we identified pre-operative hemoglobin of 120 g/L as a critical threshold for requiring transfusion. In addition, we identified significant contribution from anesthesia transfusion practice preferences. Our multivariate model indicated that these two factors are the major significant contributors to allogenic blood transfusion. Although further studies are required to better understand factors contributing to transfusion in AIS patients, we suggest standardized, peri-operative evidence-based strategies to potentially help reduce variations due to individual provider preferences

Aim. Patients with late acute periprosthetic joint infections (PJI) and treated with surgical debridement have a high failure rate. Previous studies have shown that rheumatoid arthritis (RA) is an independent risk factor for treatment failure. We conducted a case-control study to identify predictors for failure in late acute PJI treatment in RA patients. We hypothesize that patients with RA have a higher failure rate compared to controls due to the use of immunosuppressive drugs. Method. Data of an international multicenter retrospective observational study was used. Late acute PJI was defined as a sudden onset of symptoms and signs of a PJI, more than 3 months after implantation. Failure of treatment was defined as persistent signs of infection, relapse with the same or reinfection with a different micro-organism, need for prosthesis removal or death. Cases with RA were matched with cases without RA based on the affected joint. A Cox survival analyses, stratified for RA, was used to calculate hazard ratio's (HR) for failure. Subgroup analyses were used to explore other predictors for treatment failure in RA patients. Results. A total of 40 patients with RA and 80 controls without RA were included. Treatment failure occurred in 65% patients with RA compared to 45% for controls (p= .052). 68% of patients with RA used immunosuppressive drugs at time of PJI diagnosis. The use or continuation of immunosuppressive drugs in PJI was not associated with a higher failure rate; neither were the duration of symptoms and causative microorganism. The time between implantation of the prosthetic joint and diagnosis of infection was longer in RA patients: median 110 (IQR 41-171) vs 29 months (IQR 7.5–101.25). Exchange of mobile components was associated with a lower risk of treatment failure (HR 0.489, 95% CI 0.242–0.989, p-value .047). Conclusions. The use of immunosuppressive drugs does not seem to be associated with a higher failure rate in patients with RA. Mobile exchange in RA patients is associated with a lower risk of failure. This might be due to the significantly older age of the prosthesis in RA patients. Future studies are needed to explore these associations and its underlying pathogenesis

Distal radius fractures (DRFs) are common injuries that represent 17% of all adult upper extremity fractures. Some fractures deemed appropriate for nonsurgical management following closed reduction and casting exhibit delayed secondary displacement (greater than two weeks from injury) and require late surgical intervention. This can lead to delayed rehabilitation and functional outcomes. This study aimed to determine which demographic and radiographic features can be used to predict delayed fracture displacement. This is a multicentre retrospective case-control study using radiographs extracted from our Analytics Data Integration, Measurement and Reporting (DIMR) database, using diagnostic and therapeutic codes. Skeletally mature patients aged 18 years of age or older with an isolated DRF treated with surgical intervention between two and four weeks from initial injury, with two or more follow-up visits prior to surgical intervention, were included. Exclusion criteria were patients with multiple injuries, surgical treatment with fewer than two clinical assessments prior to surgical treatment, or surgical treatment within two weeks of injury. The proportion of patients with delayed fracture displacement requiring surgical treatment will be reported as a percentage of all identified DRFs within the study period. A multivariable conditional logistic regression analysis was used to assess case-control comparisons, in order to determine the parameters that are mostly likely to predict delayed fracture displacement leading to surgical management. Intra- and inter-rater reliability for each radiographic parameter will also be calculated. A total of 84 age- and sex-matched pairs were identified (n=168) over a 5-year period, with 87% being female and a mean age of 48.9 (SD=14.5) years. Variables assessed in the model included pre-reduction and post-reduction radial height, radial inclination, radial tilt, volar cortical displacement, injury classification, intra-articular step or gap, ulnar variance, radiocarpal alignment, and cast index, as well as the difference between pre- and post-reduction parameters. Decreased pre-reduction radial inclination (Odds Ratio [OR] = 0.54; Confidence Interval [CI] = 0.43 – 0.64) and increased pre-reduction volar cortical displacement (OR = 1.31; CI = 1.10 – 1.60) were significant predictors of delayed fracture displacement beyond a minimum of 2-week follow-up. Similarly, an increased difference between pre-reduction and immediate post reduction radial height (OR = 1.67; CI = 1.31 – 2.18) and ulnar variance (OR = 1.48; CI = 1.24 – 1.81) were also significant predictors of delayed fracture displacement. Cast immobilization is not without risks and delayed surgical treatment can result in a prolong recovery. Therefore, if reliable and reproducible radiographic parameters can be identified that predict delayed fracture displacement, this information will aid in earlier identification of patients with DRFs at risk of late displacement. This could lead to earlier, appropriate surgical management, rehabilitation, and return to work and function

Aims. Sickle cell disease (SCD) is an autosomal recessive inherited condition that presents with a number of clinical manifestations that include musculoskeletal manifestations (MM). MM may present differently in different individuals and settings and the predictors are not well known. Herein, we aimed at determining the predictors of MM in patients with SCD at the University Teaching Hospital, Lusaka, Zambia. Methods. An unmatched case-control study was conducted between January and May 2019 in children below the age of 16 years. In all, 57 cases and 114 controls were obtained by systematic sampling method. A structured questionnaire was used to collect data. The different MM were identified, staged, and classified according to the Standard Orthopaedic Classification Systems using radiological and laboratory investigations. The data was entered in Epidata version 3.1 and exported to STATA 15 for analysis. Multiple logistic regression was used to determine predictors and predictive margins were used to determine the probability of MM. Results. The cases were older median age 9.5 (interquartile range (IQR) 7 to 12) years compared to controls 7 (IQR 4 to 11) years; p = 0.003. After multivariate logistic regression, increase in age (adjusted odds ratio (AOR) = 1.2, 95% confidence interval (CI) 1.04 to 1.45; p = 0.043), increase in the frequency of vaso-occlusive crisis (VOC) (AOR = 1.3, 95% CI 1.09 to 1.52; p = 0.009) and increase in percentage of haemoglobin S (HbS) (AOR = 1.18, 95% CI 1.09 to 1.29; p < 0.001) were significant predictors of MM. Predictive margins showed that for a 16-year-old the average probability of having MM would be 51 percentage points higher than that of a two-year-old. Conclusion. Increase in age, frequency of VOC, and an increase in the percentage of HbS were significant predictors of MM. These predictors maybe useful to clinicians in determining children who are at risk. Cite this article: Bone Joint Open 2020;1-6:175–181

Short cementless femoral stems are increasingly popular as they allow for less dissection for insertion. Use of such stems with the anterior approach (AA) may be associated with considerable per-operative fracture risk. This study's primary aim was to evaluate whether patient-specific femoral- and pelvic- morphology and surgical technique, influence per-operative fracture risk. In doing so, we aimed to describe important anatomical thresholds alerting surgeons. This is a single-center, multi-surgeon retrospective, case-control matched study. Of 1145 primary THAs with a short, cementless stem inserted via the AA, 39 periprosthetic fractures (3.4%) were identified. These were matched for factors known to increase fracture risk (age, gender, BMI, side, Dorr classification, stem offset and indication for surgery) with 78 THAs that did not sustain a fracture. Radiographic analysis was performed using validated software to measure femoral- (canal flare index [CFI], morphological cortical index [MCI], calcar-calcar ratio [CCR]) and pelvic- (Ilium-ischial ratio [IIR], ilium overhang, and ASIS to greater trochanter distance) morphologies and surgical technique (% canal fill). Multivariate and Receiver-Operator Curve (ROC) analysis was performed to identify predictors of fracture. Femoral factors that differed included CFI (3.7±0.6 vs 2.9±0.4, p3.17 and II ratio>3 (OR:29.2 95%CI: 9.5–89.9, p<0.001). Patient-specific anatomical parameters are important predictors of fracture-risk. When considering the use of short stems via the AA, careful radiographic analysis would help identify those at risk in order to consider alternative stem options

Aim. Periprosthetic joint infection (PJI) is one of the most serious and frequent complications in prosthetic surgery. Despite significant improvements in the criteria for diagnosis of PJI, the diagnostic workflow remains complex and, sometimes, inconclusive. Host immune factors hold great potential as diagnostic biomarkers in bone and joint infections. We have recently reported that the synovial concentration of the humoral pattern recognition molecule long pentraxin 3 (PTX3) is a sensitive and specific marker of PJI in total hip and knee arthroplasty patients (THA and TKA) undergoing revision surgery [1]. However, the contribution to risk and diagnosis of PJI of the genetic variation in PTX3 and inflammatory genes that are known to affect its expression (IL-1b, IL-6, IL-10, and IL-17A) has not been addressed. Therefore, we assessed these relationships in a cohort of THA and TKA patients who underwent prosthesis revision by focusing on a panel of single nucleotide polymorphisms (SNPs) in the PTX3, IL-1β, IL-6, IL-10 and IL-17A genes. Method. A case-control retrospective study was conducted on an historic cohort of patients that received THA or TKA revision and were diagnosed with PJI (cases) or aseptic complications (controls) [1]. Samples of saliva were collected from 93 subjects and used for extraction of genomic DNA to perform genotyping of the PTX3, IL-1β, IL-6, IL-10 and IL-17A polymorphisms. Moreover, whenever available, samples of synovial fluid and plasma [1] were used to measure the concentration of the IL-1β, IL-10, and IL-6 proteins by immunoassay. Uni-and multivariate analyses were performed to evaluate the relationships between genetic, biochemical, and clinical variables. Results. The rs3024491 (IL-10) and rs2853550 (IL-1b) SNPs were found to be strongly associated with the risk of PJI. The synovial levels of PTX3, IL-1β, IL-10, and IL-6 were higher in cases than in controls, and a clear correlation emerged between the synovial concentration of PTX3 and IL-1b in cases only. Also, we identified a causal relationship between rs2853550, synovial concentration of IL-1b and that of PTX3 (that is induced by IL-1b). Conclusions. Our findings suggest that SNPs in the IL-10 and IL-1b genes could be used for early identification of THA and TKA patients with high risk of PJI. It is therefore conceivable that integrating genetic data into current diagnostic criteria would improve diagnosis of PJI

Anterior cruciate ligament (ACL) injuries are frequent among athletes and a leading cause of time away from competition. Stability of the knee involves the ACL for limiting anterior tibial translation and the ALL (anterolateral ligament) to restrain internal rotation of the tibia. Present indications for treatment with a combined ACL-ALL reconstruction remain unclear and mostly subjective. We mathematically modeled the tibial plateau geometry to try and identify patients at risk of ACL injury, and develop an objective trigger point for the decision to proceed with additional surgery to optimize rotational stability in these higher risk patients. We hypothesized that an increased convexity and steepness of the posterior aspect of the lateral plateau would subject knees to higher rotational torques leading to potentially a higher risk of ACL injury. The study design was a case-control study involving ACL reconstruction cases (n=68) and matched controls (n=68) between 2008–2015 at our institution. We used a two-dimensional approach, evaluating sagittal MRI images of the knee to model the posterior convexity of the lateral tibial plateau. Points were selected along the articular surface, and a least-squares regression was used to curve-fit a power function (y = a xn). In the equation, larger coefficient a and n represented steeper slopes. The cases and controls were compared using a Mann-Whitney-U test, and the statistical significance was set at α < 0.05. A subgroup analysis for females and males was also performed for the curve-fit coefficients. We observed a significant difference in the tibial surface geometry between our ACL reconstruction cases and matched controls (Figure 1). The modeled power equation for our ACL cases had larger coefficients compared to controls for all groups. For all pooled subjects, coefficient a (ACL recon cases = 0.90 vs controls = 0.68, p < 0.0001) and coefficient n (ACL recon cases = 0.34 vs controls = 0.30, p = 0.07) (Table 1). For the statistically significant coefficient a, we found it had a sensitivity of 78.9% and specificity of 77.5% for the statistically significant coefficient a, we found it had a sensitivity of 78.9% and specificity of 77.5% for predicting injury, using a cut off coefficient of a = 0.78. The odds ratio was 12.6 [5.5 – 29]. The posterolateral cartilaginous slope of the tibial plateau was mathematically modeled in patients with ACL injury. Patients with ACL injury demonstrated abnormally steep and fast slopes compared to controls that may play predispose to ACL injury by increasing anterior translation forces and internal rotation torques sustained by their knee joint. A steeper slope may also explain high-grade pivot shifts on physical exam that are thought to be a relative indication for adding an associated ALL reconstruction. Our findings are promising for adding more objectivity to surgical decision-making, especially with identifying high-risk patients that may be candidates for combined ACL-ALL reconstructions. For any figures or tables, please contact the authors directly

Young, active patients with end-stage medial osteoarthritis (OA) secondary to anterior cruciate ligament (ACL) deficiency present a treatment challenge for surgeons. Current surgical treatment options include high tibial osteotomy (HTO) with or without ACL reconstruction, unicompartmental knee arthroplasty (UKA) with ACL reconstruction, and total knee arthroplasty (TKA). A recent systematic review reported a much higher rate of complications in HTO combined with ACL reconstruction than with UKA-ACL (21.1% vs 2.8%), while survivorship between the two procedures was similar. UKA offers several advantages over TKA, namely faster recovery, lower blood loss, lower rate of postoperative complications, better range of motion, and better knee kinematics. However, UKA has classically been contraindicated in the presence of ACL deficiency due to reported concerns over increased incidence aseptic loosening tibia. However, as a majority of patients presenting with this pathology are young and active, concerns about implant longevity with TKRA and loss of bone stock have arisen. As a result, several authors have described combining ACL reconstruction with medial UKA to decrease the tibiofemoral translation-related stress on the tibial component, thereby decreasing aseptic loosening-related failures. The purpose of this study was to compare the functional outcomes and survivorship of combined medial UKA and ACL reconstruction (UKA-ACL) with those of a matched TKA cohort. We hypothesized that UKA-ACL patients would have better functional outcomes than TKA patients while maintaining similar survivorship. Material and Methods. We conducted a case-control study establishing UKA-ACL as the study group and TKA as the control group by a single senior surgeon between October 2005 and January 2015. We excluded patients who were over the age of 55 at the time of surgery and those who had less than two-year follow-up. A total of 21 patients (23 knees) were ultimately included in each group. Propensity matching was for age-, sex-, and body mass index (BMI)-matched control group of TKA cases. Surgical technique. UKA-ACL. This patient's had an arthroscopy to allow for tunnel preparation in the standard fashion and then the graft was passed and fixed on the femoral side. An MIS medial incision was then made to allow for insertion of the Oxford mobile-bearing unicompartmental prosthesis (Zimmer Biomet, Warsaw, IN). Primary choice of ACL graft was autogenous ipsilateral semitendinosus and gracilis tendons, which was available I and 6 of the cases were revision from previous Gore-Tex synthetic ligament reconstruction. Results. Preoperatively, baseline questionnaires demonstrated that the TKA group had scored significantly lower on the symptom subscore of the KOOS. There was no difference between the groups in the rest of the KOOS subscores, (the UCLA, and the Tegner. All scores (UCLA, and Tegner – TBC post stats) improved significantly after surgery in both groups. Improvement in each subscore of the KOOS surpassed the minimal clinically important difference in both the UKA-ACL and TKA groups. At latest follow-up, there was no significant difference between the groups on the KOOS, UCLA or Tegner, showing that our UKA-ACL patients fared as our TKA patients. This confirms that UKA-ACL is an important tool in dealing with young patients with end-stage medial OA and ACL deficiency and offers an option that leads to less bone loss and potentially easier future revision. For any figures or tables, please contact authors directly

Introduction. The alternative kinematic alignment (KA) technique for total knee arthroplasty (TKA) aims at restoring the native joint line orientation and laxity of the knee. The goal is to generate a more physiological prosthetic knee enabling higher functional performance and satisfaction for the patient. KA TKA have only been reported so far with cruciate retaining and posterior-stabilised designs. Similarly, medial pivot design for TKA has been recently developed to enable more natural knee kinematics and antero-posterior stability. The superiority of KA technique and medial pivot implant design is still controversial when compared to current practice. Our study aims to assess the value of KA TKA when performed with medial pivot implants. Methods. We conducted a retrospectively matched case-control study. Clinical data was prospectively collected on patients as part of an ongoing ODEP study. Thirty-three non-selected consecutive KA TKAs performed by the lead author were matched to a control group of 33 measured resection with mechanically aligned (MA) TKAs performed by other consultant surgeons. Patients were matched for sex, age, BMI and pre-operative Oxford Knee Score (OKS). Pre-operative median OKS was 21 points (max 48), mean age was 69, mean BMI 31, and there were 21 female patients in both arms. The medial pivot GMK Sphere implant (Medacta, Switzerland) was used in all cases. OKS and EQ-5D scores were measured pre-operatively and at 1-year post-op. Patient outcome satisfaction scores were assessed at 1-year follow-up using a visual analogic scale (VAS). Pre- and post-operative knee radiographs were analysed using TraumaCad software. Results. No reoperation or revision was recorded in either group. KA patients were found to have higher OKS (median 44 Vs 42, p=0.78), satisfaction (median 99/100 Vs 90/100, p=0.28), and EQ-5D improvement (mean 0.34 Vs 0.28, p=0.21) compared to MA patients; however, none of the differences discovered were statistically significant. In addition, KA patients had a femoral component that was on average, 3.5° more valgus orientated (aLDFA 84° Vs 80°, p<0.05) and 2.1° more flexed (4.4° Vs 2.3°, p=NS), and a tibial component with 3.6° (aMPTA 86° Vs 89.6°, p<0.05) and 3.9° (5.5° Vs 1.6°, p<0.05) increased varus orientation and posterior slope, respectively. Conclusion/Discussion. KA TKA performed with medial pivot implant design has shown good safety and efficacy at early-term. The physiological implantation provided by the KA technique seems to be clinically beneficial compared to MA implantation, although, the measured differences did not show statistical significance. Having a low study power and high ceiling effect of outcome measure tools may partly explain our results. Early results for KA TKA are encouraging and longer follow-up is warranted to assess longevity of results. For any figures or tables, please contact authors directly