Intraoperative Pelvic Tilt and Axial Rotation During Total Hip Arthroplasty Through the Direct Anterior Approach is Affected by the Acetabular Retractor and Cup Impactor.

Background: Intraoperative pelvic motion during total hip arthroplasty (THA) in the supine position affects acetabular cup placement and occurs at each step of THA; however, there are no reports of pelvic motion changes during each stage of THA via the direct anterior approach (DAA). This study aimed to evaluate pelvic motion at each step of THA through the DAA. Methods: From March to October 2022, 71 hips were prospectively measured for intraoperative pelvic tilt and axial rotation during THA through the DAA at a single center. These parameters were measured during each surgical step using the augmented reality-hip navigation system. Results: Both pelvic tilt and axial rotation were maximal during acetabular cup placement. The mean intraoperative pelvic tilt and axial rotation during cup placement were 4.8 ± 2.6° (95% confidence interval, 4.19-5.41°) and 4.2 ± 3.3° (95% confidence interval, 3.42-4.98°), respectively. The effects of the acetabular retractor and cup impactor on pelvic tilt and axial rotation were comparable. Spearman's correlation tests showed significant correlation between axial rotation and body mass index (r = -0.444, P = .00011). Conclusions: The pelvis tilts forward and rotates toward the surgical side during THA through the DAA. The effects of the acetabular retractor and cup impactor on pelvic motion are comparable. Cup implantation must take into account pelvic movement, and it must be recognized that the pelvis is moving at that time, even with only the acetabular retractor inserted, compared to before the skin incision.

Effect of Antimicrobial Prophylaxis Duration on Health Care-Associated Infections After Clean Orthopedic Surgery: A Cluster Randomized Trial.

Importance: Postoperative health care-associated infections are associated with a greater deterioration in patients' general health status and social and economic burden, with at least 1 occurring in approximately 4% of acute care hospital patients. Antimicrobial prophylaxis prevents surgical site infections in various orthopedic procedures; however, its relationship with health care-associated infections remains unknown. Objective: To examine whether a shorter antimicrobial prophylaxis duration of less than 24 hours after surgery is not inferior to a longer duration in preventing health care-associated infections after clean orthopedic surgery. Design, Setting, and Participants: This open-label, multicenter, cluster randomized, noninferiority clinical trial was conducted in 5 tertiary referral hospitals in greater Tokyo metropolitan area, Japan, from May to December 2018. Adult patients undergoing clean orthopedic surgery were recruited until the planned number of participants was achieved (500 participants per group). Statistical analysis was conducted from July to December 2019. Interventions: Antimicrobial prophylaxis was discontinued within 24 hours after surgery in group 24 and 24 to 48 hours after surgery in group 48. Group allocation was switched every 2 or 4 months according to the facility-based cluster rule. Study-group assignments were masked from participants. Main Outcomes and Measures: The primary outcome was the incidence of health care-associated infections requiring antibiotic therapies within 30 days after surgery. The noninferiority margin was 4%. Results: Of the 1211 participants who underwent cluster allocation, 633 participants were in group 24 (median [IQR] age, 73 [61-80] years; 250 men [39.5%] and 383 women [60.5%]), 578 participants were in group 48 (median [IQR] age, 74 [62-81] years; 204 men [35.3%] and 374 women [64.7%]), and all were eligible for the intention-to-treat analyses. Health care-associated infections occurred in 29 patients (4.6%) in group 24 and 38 patients (6.6%) in group 48. Intention-to-treat analyses showed a risk difference of -1.99 percentage points (95% CI, -5.05 to 1.06 percentage points; P < .001 for noninferiority) between groups, indicating noninferiority. Results of adjusted intention-to-treat, per-protocol, and per designated procedure population analyses supported this result, without a risk of antibiotic resistance and prolonged hospitalization. Conclusions and Relevance: This cluster randomized trial found noninferiority of a shorter antimicrobial prophylaxis duration in preventing health care-associated infections without an increase in antibiotic resistance risk. These findings lend support to the global movement against antimicrobial resistance and provide additional information on adequate antimicrobial prophylaxis for clean orthopedic surgery. Trial Registration: Identifier: UMIN000030929.

Short-term clinical and radiographic outcomes of total hip arthroplasty with PMPC-grafted highly cross-linked polyethylene liners against 32-mm femoral heads.

We evaluated the clinical and radiographic outcomes of femoral head penetration and total hip arthroplasties with untreated and poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted highly cross-linked polyethylene (HXLPE) acetabular liners against 26-, 28-, and 32-mm cobalt-chromium alloy femoral heads 3 years after the index surgery. Three combinations of the articulating surfaces were evaluated in the present study: untreated or PMPC-grafted HXLPE liner against 26- or 28-mm femoral heads (n = 16, 24) [control (26 or 28 mm) and PMPC (26 or 28 mm)] and PMPC-grafted HXLPE liner against 32-mm femoral heads (n = 64) [PMPC (32 mm)]. The clinical outcomes improved at 3 years postoperatively for the groups. No periprosthetic osteolysis or acetabular component migration was detected, and no revision surgery was performed among the groups. The steady-state wear rate of the PMPC (26 or 28 mm) group (0.021 mm/year) was lower than that of the control (26 or 28 mm) group (- 0.015 mm/year); the steady-state wear was under the clinical threshold. In contrast, the steady-state wear rate of the PMPC (32 mm) group (-0.006 mm/year) showed no significant difference when compared to that of the PMPC (26 or 28 mm) group (p < 0.01). The results obtained in the present study clearly demonstrate that PMPC-grafting onto an HXLPE surface improved the wear resistance of acetabular liners, even when coupled with larger femoral heads. Although further follow-up evaluations are required, PMPC-grafted HXLPE acetabular liners may be a promising approach to extend the longevity of artificial joints.

Association Between Normothermia at the End of Surgery and Postoperative Complications Following Orthopedic Surgery.

BACKGROUND: Maintaining perioperative normothermia is recommended by recent guidelines for the prevention of surgical site infections (SSIs). However, the majority of supporting data originates outside the field of orthopaedic surgery. METHODS: The effect of normothermia was explored using the prospectively collected data of consecutive patients who underwent single-site surgery in 7 tertiary referral hospitals between November 2013 and July 2016. SSIs, urinary tract infections (UTIs), respiratory tract infections (RTIs), cardiac and cerebral events (CCE), and all-cause mortality rates within 30 days after surgery were compared between patients with normothermia (body temperature ≥36°C) and those with hypothermia (<36°C) at the end of surgery, after closure. Multivariable adjusted and inverse-probability weighted regression analyses were performed. RESULTS: The final cohort included 8841 patients. Of these, 11.4% (n = 1008) were hypothermic. More than 96% were evaluated in person by the physicians. After adjusting for multiple covariates, normothermia was not significantly associated with SSIs (adjusted odds ratio [aOR] 1.18, 95% confidence interval [CI] 0.59-2.33), UTIs (aOR 1.14, 95% CI 0.66-1.95), RTIs (aOR 0.60, 95% CI 0.31-1.19), or CCE (aOR 0.53, 95% CI 0.26-1.09). In contrast, normothermia was associated with a lower risk of 30-day mortality (aOR 0.26, 95% CI 0.11-0.64; P < .01; weighted hazard ratio 0.21, 95% CI 0.07-0.68; P = .002). In a subgroup analysis, normothermia was associated with reduced mortality in all types of surgical procedures. CONCLUSIONS: Whereas our findings suggest no clear association with SSI risks following orthopedic surgery, our study supports maintaining perioperative normothermia, as it is associated with reduced 30-day mortality.

Outcomes of an Intraoperative Povidone-Iodine Irrigation Protocol in Spinal Surgery for Surgical Site Infection Prevention.

STUDY DESIGN: This was a retrospective observational study. OBJECTIVE: The aim of this study was to evaluate the efficacy of our new protocol for preventing postoperative surgical site infection (SSI) following spinal surgery. SUMMARY OF BACKGROUND DATA: SSI following spinal surgery is a serious postoperative complication. Several studies have recently assessed the effectiveness of wound irrigation with povidone-iodine (PVP-I) for SSI prevention, but no consensus has been reached as to how PVP-I should be used in clinical practice. We formed a PVP-I irrigation protocol focusing on the pharmacological properties of PVP-I. This study aimed to evaluate the efficacy and safety of our protocol for preventing SSI. MATERIALS AND METHODS: All cases of spinal surgery at our hospital between October 2011 and September 2016 were retrospectively reviewed. The exclusion criteria were PVP-I allergy, prior surgical debridement for infection, and implant removal surgery. The patients were subdivided into those who had received normal saline irrigation after 90 seconds of 1% PVP-I pooling every 1.5 hours (study group) or only routine saline irrigation every 1.5 hours (control group). The study and control groups comprised of 177 and 146 patients, respectively. This study compared the rate of SSI with and without the use of the PVP-I irrigation protocol. RESULTS: The SSI rates were 1.7% for the study group (3/177 patients) and 3.4% for the control group (5/146 patients), showing no significant statistical difference (P=0.32). There were no cases of deep SSI in the study group, whereas there were 4 cases in the control group. The deep SSI rate significantly decreased in the study group (P=0.027). No adverse events occurred in the study group. CONCLUSION: In this study, 90 seconds of 1% PVP-I pooling every 1.5 hours followed by saline irrigation demonstrated the effectiveness of our protocol for the prevention of postoperative deep SSI after spinal surgery.

Subtrochanteric Fracture of the Femur Accompanying Pre-existing Ipsilateral Osteoarthritis of the Hip Successfully Treated with Intramedullary Nailing in the Lateral Decubitus Position: A Case Report.

A subtrochanteric fracture of the femur accompanying pre-existing osteoarthritis of the ipsilateral hip is rare. A deformity of the hip joint complicates the insertion of the intramedullary nail and varus malreduction is anticipated when surgery is performed on a fracture table with a perineal post. We report a successful case of intramedullary fixation performed in the lateral decubitus position and discuss the importance of avoiding varus and the superiority of the lateral position in surgery.

Poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liner in primary total hip replacement: one-year results of a prospective cohort study.

To control particle-induced osteolysis in total hip replacement (THR), we developed a new technique to graft poly(2-methacryloyloxyethyl phosphorylcholine) onto the surface of polyethylene liners. A prospective cohort study was conducted to investigate the clinical safety of this novel bearing surface. Between April 2007 and September 2008, we recruited a prospective consecutive series of 80 patients in five participating hospitals. These patients received a cementless THR; a 26-mm-diameter cobalt-chromium-molybdenum alloy ball and a poly(2-methacryloyloxyethyl phosphorylcholine)-grafted cross-linked polyethylene liner were used for the bearing couplings. These individuals were followed a year postoperatively. An evaluation of clinical performance was conducted through an assessment of hip joint function based on the evaluation chart authorized by the Japanese Orthopaedic Association. No patients were lost to follow-up. No adverse events were found to be correlated with the implanted liners. The average hip joint function score improved from 43.2 preoperatively to 91.7 postoperatively at 1 year. There was no implant migration nor periprosthetic osteolysis detected on radiographic analysis. On the basis of our results, we conclude that poly(2-methacryloyloxyethyl phosphorylcholine)-grafted cross-linked polyethylene liners are a safe implant option for hip replacement surgery for short-term clinical use.

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia.

BACKGROUND: We conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed. METHODS: Seven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval. RESULTS: The stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males. CONCLUSIONS: These findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Analysis of interobserver reliability for radiographic staging of coxarthrosis and indexes of acetabular dysplasia: a preliminary study.

BACKGROUND: We are planning a multicenter survey on coxarthrosis and acetabular dysplasia in Japan. To collect reliable data, we performed a preliminary study to elucidate the observer agreement on assessment items. METHODS: We collected radiographs of hip joints in eight patients with various findings of coxarthrosis. Twelve registered orthopedic specialists evaluated them regarding the roentgenographic stage of coxarthrosis and five indexes of acetabular dysplasia (acetabular angle, center-edge angle, acetabular roof obliquity, acetabular head quotient, approximate acetabular quotient). To assess observer agreement, we calculated the value of the kappa statistic for stages and the coefficient of variation for the indexes. The same 12 specialists then assessed the coxarthritis stage on the same radiographs 1 month after the first evaluation based on our own descriptions of the roentgenographic stages. RESULTS: For the first evaluation of the roentgenographic stage, the value of the kappa statistic was 0.448; and for the second evaluation it was 0.600. The results of the coefficient of variation for the indexes of acetabular dysplasia, ranked in ascending order, were as follows: acetabular angle, acetabular head quotient, acetabular roof obliquity, center-edge angle, approximate acetabular quotient. CONCLUSIONS: For the upcoming multicenter survey, clear descriptions of the stages of coxarthrosis and selection of appropriate indexes can be helpful for collecting dependable results.

Successful ambulation by surgical conversion in a complex form of epigastric heteropagus.

A female neonate with a complex form of epigastric heteropagus and with three legs was referred to us. The left leg appeared normal, the central one was hypoplastic and resected 1 month after birth, and the right one projected in the cranial direction with knee flexion contracture. Three bones of the parasite were sandwiched between the right ilium and the ischiopubic bones of the autosite. At the age of 4, we performed the subtrochanteric femoral osteotomy with 90 degrees of varization and rotation, along with knee disarticulation. Ambulation was successfully achieved with the prosthesis with a multiaxis knee unit.

Wear resistance of artificial hip joints with poly(2-methacryloyloxyethyl phosphorylcholine) grafted polyethylene: comparisons with the effect of polyethylene cross-linking and ceramic femoral heads.

Aseptic loosening of artificial hip joints induced by wear particles from the polyethylene (PE) liner remains the ruinous problem limiting their longevity. We reported here that grafting with a polymer, poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) (PMPC), on the PE liner surface dramatically decreased the wear production under a hip joint simulator condition. We examined that the effect of properties of both PE by cross-linking and femoral head by changing the materials on wearing properties of PE. The PMPC grafting on the liners increased hydrophilicity and decreased friction torque, regardless of the cross-linking of the PE liner or the difference in the femoral head materials. During the hip joint simulator experiments (5 x 10(6) cycles of loading), cross-linking caused a decrease of wear amount and a reduction of the particle size, while the femoral head materials did not affect it. The PMPC grafting abrogated the wear production, confirmed by almost no wear of the liner surface, independently of the liner cross-linking or the femoral head material. We concluded that the PMPC grafting on the PE liner surpasses the liner cross-linking or the change of femoral head materials for extending longevity of artificial hip joints.

Preparing a version of the Nottingham Adjustment Scale (for psychological adjustment) tailored to osteoarthritis of the hip.

BACKGROUND: The Nottingham Adjustment Scale-Japanese version (hereinafter referred to as NAS-J) was developed to measure psychological adaptation to visually impairment. Several disease-specific modified versions have been developed in Japan. The purpose of this study was to develop and test the reliability, validity, and responsiveness of the NAS-J for hip osteoarthritis patients. METHODS: Patients with osteoarthritis of the hip managed as outpatients at the Department of Orthopaedic Surgery of one university hospital gave informed written consent to be enrolled in this study. Subjects were asked to complete a questionnaire consisting of the NAS-J--Hip edition (hereinafter referred to as NAS-J-HIP), health-related QOL (Short Form 36). Subjects' medical and treatment histories, and the Japanese Hip Society's Evaluation Chart of Hip Joint Functions (hereinafter referred to as the JOA score) were also collected from their medical records. Psychometric analyses were conducted to test reliability, validity, and responsiveness. RESULTS: A total of 231 patients agreed to participate in the survey, and responses were obtained from 168 (72.7%). Their mean +/- SD age was 52.5 +/- 12.4 years, and the mean JOA score was 80.9 points. By factor analysis using the principal factor method, seven factors were extracted: (1) anxiety/depression, (2) self-esteem, (3) attitude, (4) locus of control, (5) acceptance, (6) self-efficacy, and (7) attributional style. Concurrent validity was the result according to the near hypothesis. Cronbach's alpha-coefficient ranged from 0.68 to 0.83, indicating high internal consistency. CONCLUSIONS: For hip osteoarthritis patients, construct validity was confirmed for NAS-J-HIP. Furthermore, seven factors comprising 27 items with high internal consistency were incorporated into NAS-J-HIP. This scale can be used to assess the psychological adaptation of hip osteoarthritis patients.

Ripple reduction control of the undulation pump total artificial heart.

An undulation pump total artificial heart (UPTAH) in which the revolutions of the motor are converted to undulation motion of a disk has been developed. In an experiment, a goat using the UPTAH survived for 54 days. However, a large ripple was observed in the device's output pressure and flow waveform. In calculating the spectrum of the ripple, we found that the ripple mainly comprised 2 frequency sine waves: 1 having the same frequency as and 1 having double the frequency of the motor revolutions. To reduce the ripple, 2 sine waves, 1 having the same frequency as and 1 having double the frequency of the motor revolutions, were provided to the motor current to modulate the pulse width of the pulse width modulation controlling the motor revolutions. This ripple control method reduced the pressure ripple by 90% in a mock circulation and by 70% in animal experiments. These results revealed that the ripple generated in the UPTAH could be controlled through the use of motor control software.

Ten-year follow-up of a proximal circumferential porous-coated femoral prosthesis: radiographic evaluation and stability.

We studied the radiographic findings on 48 hips in 48 patients to determine the stability of a proximal circumferential porous-coated femoral prosthesis in cementless total hip replacement. The patients had coxarthrosis related to acetabular dysplasia. The follow-up interval in the study was 10 to 13 years. In 36 patients, migration of the femoral component was equal to or less than 2 mm. No patient showed progressive migration. Revision surgery was performed in 37 patients because of migration of the acetabular components. Intraoperatively, no femoral components demonstrated visible motion under stress of the implant-bone interface, and none had been revised. During the follow-up period, two patients had mild thigh pain. Two others sustained fracture of the femur 11 years after surgery due to a fall. Pedestal formation was observed in 39 patients and calcar rounding in 21. The mean diameter of the medullary cavity around the distal part of the prosthesis increased from 13.6 to 16.3 mm average. We conclude that the proximal circumferential porous-coated femoral prosthesis is stable for more than ten years after surgery. The risk of subsequent periprosthetic fractures in elderly patients, however, is a matter of concern.

Nonself-centering Bateman bipolar endoprosthesis for nontraumatic osteonecrosis of the femoral head: a 12- to 18-year follow-up study.

We studied the long-term results of bipolar endoprosthetic replacement in 12 patients (12 hips) 12 to 18 years after surgery. These patients had Ficat stage III nontraumatic osteonecrosis of the femoral head. The original Bateman universal proximal femoral endoprosthesis, which did not have a self-centering mechanism, was inserted without cement as a primary surgical intervention. Three patients underwent revision surgery, 3, 17, and 17 years after surgery, respectively. The reasons for revision surgery were migration of the stem in 2 patients and migration of both the stem and the outer cup in 1. In the remaining 9 patients, the total Merle d'Aubigné and Postel score was 16.1 +/-1.3 at the time of follow-up. Radiographs showed migration of the endoprosthesis in 1 of these 9 patients. Thus, 11 of the 12 patients retained the endoprosthesis 12 years or more after implantation. We concluded that the original Bateman endoprosthesis was effective in delaying the need for total hip replacement for more than 10 years in patients with Ficat stage III nontraumatic osteonecrosis of the femoral head.