Aims. This study aimed to investigate the risk of postoperative complications in COVID-19-positive patients undergoing common orthopaedic procedures. Methods. Using the National Surgical Quality Improvement Programme (NSQIP) database, patients who underwent common orthopaedic surgery procedures from 1 January to 31 December 2021 were extracted. Patient preoperative COVID-19 status, demographics, comorbidities, type of surgery, and postoperative complications were analyzed. Propensity score matching was conducted between COVID-19-positive and -negative patients. Multivariable regression was then performed to identify both patient and provider risk factors independently associated with the occurrence of 30-day postoperative adverse events. Results. Of 194,121 included patients, 740 (0.38%) were identified to be COVID-19-positive. Comparison of comorbidities demonstrated that COVID-19-positive patients had higher rates of diabetes, heart failure, and pulmonary disease. After propensity matching and controlling for all preoperative variables, multivariable analysis found that COVID-19-positive patients were at increased risk of several postoperative complications, including: any adverse event, major adverse event, minor adverse event, death, venous thromboembolism, and pneumonia. COVID-19-positive patients undergoing hip/knee arthroplasty and trauma surgery were at increased risk of 30-day adverse events. Conclusion. COVID-19-positive patients undergoing orthopaedic surgery had increased odds of many 30-day postoperative complications, with hip/knee arthroplasty and trauma surgery being the most high-risk procedures. These data reinforce prior literature demonstrating increased risk of venous thromboembolic events in the acute postoperative period. Clinicians caring for patients undergoing orthopaedic procedures should be mindful of these increased risks, and attempt to improve patient care during the ongoing global pandemic. Cite this article: Bone Jt Open 2023;4(9):704–712

Aim. Whether laminar airflow (LAF) in the operating room (OR) is effective for decreasing periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant yet controversial issue. This study investigated the association between operating room ventilation systems and the risk of PJI in TJA patients. Method. We performed a retrospective observational study on consecutive patients undergoing primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) from January 2013-September 2017 in two surgical facilities within a single institution, with a minimum 1-year follow-up. All procedures were performed by five board-certified arthroplasty surgeons. The operating rooms at the facilities were equipped with LAF and turbulent ventilation systems, respectively. Patient characteristics were extracted from clinical records. PJI was defined according to Musculoskeletal Infection Society criteria within 1-year of the index arthroplasty. A multivariate logistic regression model was performed to explore the association between LAF and risk of 1-year PJI, and then a sensitivity analysis using propensity score matching (PSM) was performed to further validate the findings. Results. A total of 6,972 patients (2,797 TKA, 4,175 THA) were included. The incidence of PJI within 1 year for patients from the facility without laminar flow was similar at 0·4% to that of patients from the facility with laminar flow at 0·5%. In the multivariate logistic regression analysis, after all confounding factors were taken into account, the use of LAF was not significantly associated with reduction of the risk of PJI. After propensity score matching, there was no significant difference in the incidence of PJI within 1 year for patients between the two sites. Conclusions. The use of LAF in the operating room was not associated with a reduced incidence of PJI following primary TJA. With an appropriate perioperative protocol for infection prevention, LAF does not seem to play a protective role in PJI prevention

Introduction. Robotic-assisted hip arthroplasty helps acetabular preparation and implantation with the assistance of a robotic arm. A computed tomography (CT)-based navigation system is also helpful for acetabular preparation and implantation, however, there is no report to compare these methods. The purpose of this study is to compare the acetabular cup position between the assistance of the robotic arm and the CT-based navigation system in total hip arthroplasty for patients with osteoarthritis secondary to developmental dysplasia of the hip. Methods. We studied 31 hips of 28 patients who underwent the robotic-assisted hip arthroplasty (MAKO group) between August 2018 and March 2019 and 119 hips of 112 patients who received THA under CT-based navigation (CT-navi group) between September 2015 and November 2018. The preoperative diagnosis of all patients was osteoarthritis secondary to developmental dysplasia of the hip. They received the same cementless cup (Trident, Stryker). Robotic-assisted hip arthroplasty were performed by four surgeons while THA under CT-based navigation were performed by single senior surgeon. Target angle was 40 degree of radiological cup inclination (RI) and 15 degree of radiological cup anteversion (RA) in all patients. Propensity score matching was used to match the patients by gender, age, weight, height, BMI, and surgical approach in the two groups and 30 patients in each group were included in this study. Postoperative cup position was assessed using postoperative anterior-posterior pelvic radiograph by the Lewinnek's methods. The differences between target and postoperative cup position were investigated. Results. The acetabular cup position of all cases in both Mako and CT-navi group within Lewinnek's safe zone (RI: 40±10 degree; RA: 15±10 degree) in group were within this zone. Three was no significant difference of RI between Mako and CT-navi group (40.0 ± 2.1 degree vs 39.7± 3.6 degree). RA was 15.0 ± 1.2 degree and 17.0 ± 1.9 degree in MAKO group and in CT-navi group, respectively, with significant difference (p<0.001). The differences of RA between target and postoperative angle were smaller in MAKO group than CT-navi group (0.60± 1.05 degree vs 2.34± 1.40 degree, p<0.001). The difference or RI in MAKO group was smaller than in CT-navi, however, there was no significance between them (1.67± 1.27 degree vs 2.39± 2.68 degree, p=0.197). Conclusions. Both the assistance of the robotic arm and the CT-based navigation system were helpful to achieve the acetabular cup implantation, however, MAKO system achieved more accurate acetabular cup implantation than CT-based navigation system in total hip arthroplasty for the patients with OA secondary to DDH. Longer follow-up is necessary to investigate the clinical outcome

Objectives. For patients with Developmental Dysplasia of the Hip (DDH) who progress to needing total joint arthroplasty it is important to understand the morphology of the femur when planning for and undertaking the surgery, as the surgery is often technically more challenging in patients with DDH on both the femoral and acetabular parts of the procedure. 1. The largest number of male DDH patients with degenerative joint disease previously assessed in a morphological study was 12. 2. In this computed tomography (CT) based morphological study we aimed to assess whether there were any differences in femoral morphology between male and female patients with developmental dysplasia undergoing total hip arthroplasty (THA) in a cohort of 49 male patients, matched to 49 female patients. Methods. This was a retrospective study of the pre-operative CT scans of all male patients with DDH who underwent THA at two hospitals in Japan between 2006–2017. Propensity score matching was used to match these patients with female patients in our database who had undergone THA during the same period, resulting in 49 male and 49 female patients being matched on age and Crowe classification. The femoral length, anteversion, neck-shaft angle, offset, canal-calcar ratio, canal flare index, lateral centre-edge angle, alpha angle and pelvic incidence were measured for each patient on their pre-operative CT scans. Results. Significant differences were found in femoral anteversion with a mean male anteversion of 22 ˚ (±14.2), compared to 30˚ (±15.5), in females (p=0.02, Confidence Interval (C.I.) 1.6 to 14.9, Figure 1), offset, with a mean male offset of 31 mm (±6.2), compared to 29 mm (±6.1) in females, (p=0.04, C.I: 0.2 to 4.8), and femoral length with a mean femoral length of 434 mm in males (±22.2), compared to 407 mm in females (±23.9), (p<0.001, C.I: 19.2 to 34.3, Figure 2). No significant differences between male and female patients were found for the other measurements. Discussion. This was the first study of this size assessing femoral morphology in male patients with DDH undergoing THA. Significant differences were found between male and female patients in femoral anteversion, length and offset. This should be taken into account when planning and performing THA in these patients. Based on the findings from this study, a more anteverted femoral neck can be expected at the time of surgery in a female patient with DDH undergoing total hip arthroplasty, compared to a male patient

Introduction. Hip osteoarthritis (OA) results in reduced hip range of motion and contracture, affecting sitting and standing posture. Spinal pathology such as fusion or deformity may alter the ability to compensate for reduced joint mobility in sitting and standing postures. The effects of postural spinal alignment change between sitting and standing is not well understood. Methods. A retrospective radiographic review was performed at a single academic institution of patients with sitting and standing full-body radiographs between 2012 and 2017. Patients were excluded if they had transitional lumbosacral anatomy, prior spinal fusion or hip prosthesis. Hip OA severity was graded by the Kellgren-Lawrence grades and divided into two groups: low-grade OA (LOA; grade 0–2) and severe OA (SOA; grade 3–4). Spinopelvic parameters (Pelvic Incidence (PI), Pelvic Tilt (PT), Lumbar Lordosis (LL), and PI-LL), Thoracic Kyphosis (TK; T4-T12), Global spinal alignment (SVA and T1-Pelvic Angle; TPA; T10-L2) as well as proximal femoral shaft angle (PFSA: as measured from the vertical), and hip flexion (difference between change in PT and change in PFSA) were also measured. Changes in sit-stand radiographic parameters were compared between the LOA and SOA groups with unpaired t-test. Results. 548 patients were identified with sit-stand radiographs, of which there were 311 patients with LOA & 237 with SOA. After propensity score matching for Age, BMI, and PI, 183 LOA & 183 SOA patients were analyzed. Standing alignment analysis demonstrated that SOA patients had greater SVA (31.1 ± 36.68 vs 21.7 ± 38.83, p=0.02), and lower TK (−36.21 ± 11.98 vs −41.09 ± 11.47, p<0.001). SOA patients had lower PT, greater PI-LL, lower LL, lower T10-L2, and lower TPA (p>0.05). PFSA (9.09 5.19 vs 7.41 4.48, p<0.001) was significantly different compared to LOA while SOA KA was not significantly different compared to LOA. Sitting alignment analysis demonstrated that SOA patients had higher PT (29.69 ± 15.65 vs 23.32 ± 12.12, p<0.001), higher PI-LL (21.64 ±17.86 vs 12.44 ±14.84 p<0.001), lower LL (31.67 ± 16.40 vs 41.58 ± 14.73, p<0.001), lower TK (−33.22 ± 15.76 vs −38.57 ± 13.01, p=0.01), greater TPA (27.91 ± 14.7 vs 22.55 ± 11.38 p=0.01). TK, SVA, and PFSA were not significantly different compared to LOA. SOA and LOA groups demonstrated differences in standing and sitting spinopelvic alignment for all global and regional parameters except PI. When examining the postural changes from standing to sitting, there was less hip ROM in SOA than LOA (71.45 ± 18.55 vs 81.64 ± 12.57, p<0.001). As a result, SOA patients had more change in PT (15.24 ± 16.32 vs 7.28 ± 10.19, p<0.001), PI-LL (20.62 ± 17.25 vs 13.74 ± 11.16, p<0.001), LL (−21.37 ± 15.55 vs −13.09 ± 12.34, p<0.001), and T10-L2 (−4.94 ± 7.45 vs −1.08 ± 5.19, p<0.001) to compensate. SOA had a greater improvement in TPA (15.06 vs 9.59, p<0.001), and less change in PFSA (86.65 vs 88.81, p<0.001) compared to LOA. Conclusions. Spinopelvic compensatory mechanisms are adapted for reduced joint mobility associated with hip OA in standing and sitting

Introduction. Legg-Calve-Perthes disease (LCPD), a juvenile osteonecrosis of the femoral head (ONFH), can remain sequelae around hip joint, and results in osteoarthritis necessitating total hip arthroplasty (THA) in middle-age. THA for sequelae of LCPD needs specific concerns for anatomical deformity, leg length discrepancy (LLD), and relatively young patient's age. To date, few studies are available for the results of THA for LCPD sequelae. Moreover, there was no study for the result of Alumina-Alumina THA (Al-Al THA) in patient with LCPD sequelae, even excellent long term outcome of Al-Al THA has been documented in relatively young patients. The aim of this retrospective study is to evaluate the clinical and radiological outcome of Al-Al THA for LCPD sequelae, especially in terms of the restoration of LLD and the occurrence of complication. In addition, we compared the results of THA for LCPD sequelae with those for adult onset ONFH, in which THA is necessitated in relatively young age and excellent long term outcome has been proven after Al-Al THA. Method. Between 1997 and 2007, 41 cementless Al-Al THA were performed in 37 patients with LCPD sequelae and followed up for mean, 10.4 years. Mean age at THA was 43.6 years. Using the propensity score matching with age, gender, and the length of follow-up as variables, 41 THAs in 37 patients were identified from 339 hips in 256 patients who underwent primary Al-Al THA for ONFH during the same period. Clinical and radiological outcomes in terms of implant survival, Harris hip score (HHS), LLD change, and perioperative complication were compared between the two groups. Results. In LCPD group, there was no revision during follow-up period. All stems and cups were survived without osteolysis or loosening at last follow-up. HHS increased significantly from 70.9±12.9 point to 97.4±5.4 point (p<0.001). LLD decreased significantly from 2.0±1.2 cm to 0.2±0.9 cm. (p<0.001). Fourteen intraoperative femoral cracks occurred. One patient showed peroneal nerve palsy after surgery. There was one patient with deep vein thrombosis without pulmonary embolism. In ONFH group, there was also no revision during follow-up and all implant was radiologically stable without evidence of osteolysis or loosening. HHS increased significantly from 44.9±21.4 point to 96.6±4.6 point (p<0.001). LLD decreased significantly from 0.5±0.8 cm to 0.1±0.9 cm. There were 6 intraoperative femoral fractures. Also, there was 2 more postoperative periprosthetic fractures after trauma and 1 postoperative dislocation. Even the implant survival was not different between two groups, LCPD group showed higher rate of overall complication (p=0.04) and intraoperative femoral fracture (p=0.027) than ONFH group. Conclusion. Outcomes of Al-Al THA in patients with sequelae of LCPD were comparable to those in patients with ONFH clinically and radiologically. LLD was restored after THA without troublesome neurologic complication in both groups. Although high rate of intraoperative femoral crack was revealed in LCPD group, fracture union was achieved in all hips without stem loosening. As with ONFH, Al-Al THA may be a reliable treatment option for the patients with LCPD sequelae