Pedicle screw placement safety with the aid of patient-specific guides in a case series of patients with thoracic scoliosis.

PURPOSE: Pedicle screw (PS) placement in thoracic scoliotic deformities can be challenging due to altered vertebral anatomy; malposition can result in severe functional disability or inferior construct stability. Three-dimensional (3D) printed patient-specific guides (PSGs) have been recently used to supplement other PS placement techniques. We conducted a single-center, retrospective observational study to assess the accuracy of PS placement using PSGs in a consecutive case series of pediatric and adult patients with thoracic scoliosis. METHODS: We analyzed the data of patients with thoracic scoliosis who underwent PS placement using 3D-printed PSG as a vertebral cannulation aid between June 2013 and July 2018. PS positions were determined via Gertzbein-Robbins (GR) and Heary classifications on computed tomography images. We determined the concordance of actual and preoperatively planned PS positions and defined the technique learning curve using a receiver-operating characteristic (ROC) curve. RESULTS: We performed 362 thoracic PS placement procedures in 39 consecutive patients. We classified 352 (97.2%), 2 (0.6%), and 8 (2.2%) screws as GR grades 0 (optimal placement), I, and II, respectively. The average instrumented PS entry point offsets on the X- and Y-axes were both 0.8 mm, and the average differences in trajectory between the planned and the actual screw placements on the oblique sagittal and oblique transverse planes were 2.0° and 2.4°, respectively. The learning process was ongoing until the first 12 PSs were placed. CONCLUSIONS: The accuracy of PS placement using patient-specific 3D templates in our case series exceeds the accuracies of established thoracic PS placement techniques.

A novel concept of cam-type femoroacetabular impingement treatment with patient-specific template guided osteochondral deformity ablation.

PURPOSE: To present a novel surgical concept for the cam-type femoroacetabular impingement (FAI) treatment and to assess and report the clinical outcomes. METHODS: We performed a retrospective study of a single-surgeon case series of six hips in five consecutive male patients with symptomatic cam-type FAI, treated with the mini-open anterior hip approach with a patient-specific template (PST)-guided deformity ablation between 2015 and 2018. We assessed the hip range of motion, iHOT-33, Tegner, and EQ-5D before surgery and after a minimum follow-up of 30 months. RESULTS: The average age was 37 ± 13.3 years, average BMI was 31.1 ± 3.3 kg/m2, and average pre-surgery Tönnis hip osteoarthritis (OA) grade was 1 ± 1. The average surgery duration was 71 ± eight minutes. The average estimated blood loss was 83 ± 26 ml. After a mean follow-up of 50 ± 12 months, we observed no OA progression with no change in Tönnis hip OA grades. Hip flexion and internal rotation significantly improved (p = 0.007; p = 0.048) from mean 98° ± 9° and 14° ± 11° to mean 113° ± 8° and 23° ± 8°, respectively. iHOT-33, Tegner, and EQ-5D improved significantly (p = < 0.001; p = 0.004; p = < 0.001) from mean 44.7 ± 12.2, 3 ± 1, and 0.513420 ± 0.101389 to mean 94 ± 2.7, 5 ± 1, and 1.000000 ± 0, respectively. One patient needed revision surgery for heterotopic ossification removal, with no sequelae at the last follow-up. CONCLUSION: Mini-open anterior hip approach with the PST-guided cam-type FAI deformity ablation presents an accurate and reproducible solution for cam-type FAI surgical treatment, with promising clinical outcomes. Using a PST in the cam-type FAI surgery may present a powerful additional tool in the existing open techniques armamentarium.

Bernese peri-acetabular osteotomy performed with navigation and patient-specific templates is a reproducible and safe procedure.

PURPOSE: To present a novel surgical technique for the Bernese peri-acetabular osteotomy (PAO) using electromagnetic navigation (EMN) and patient-specific templates (PST), and to evaluate it against the traditional fluoroscopic technique. METHODS: We included 40 dysplastic hips. All PAOs were performed using PST and EMN. We recorded learning-related complications. For the purpose of acetabular fragment correction analysis, patients were divided into two groups. In the study group (EMN group, 30 hips), the acetabular fragment was reoriented with the help of EMN. In the control group (XR group, 10 hips), the acetabular fragment was reoriented using fluoroscopy. We compared the difference between the planned and achieved position of the acetabular fragment and outcomes between both groups. RESULTS: Two major complications occurred in four PAOs in the XR group only (first ten PAOs). The average absolute difference in planned and achieved lateral centre -edge angle (LCEA) and acetabular index (AI) was 1.2° ± 1.5° and 1.1° ± 2° for the EMN and 7° ± 6.1° and 6.3° ± 6.3° for the XR group (p = 0.02; p = 0.03). The average surgery duration was 183 ± 32 minutes for the EMN and 203 ± 42 minutes for the XR group (p = 0.19). At the last follow-up, the average Harris Hip Score (HHS) value was 88 ± 12 in the EMN and 86 ± 14 in the XR group (p = 0.84). CONCLUSIONS: Our study indicates that PAO performed with EMN and PST seems to be a safe and reproducible procedure with a short learning curve. Additionally, navigated reorientation of the acetabular fragment is significantly more accurate than the fluoroscopic technique.

Electromagnetic navigation system for acetabular component placement in total hip arthroplasty is more precise and accurate than the freehand technique: a randomized, controlled trial with 84 patients.

Background and purpose - The accuracy of conventional navigation systems depends on precise registration of bony landmarks. We investigated the clinical use of electromagnetic navigation (EMN), with a unique device for precise determination of the anterior pelvic plane. Patients and methods - We randomly allocated patients scheduled for total hip arthroplasty into 2 groups of 42 patients each. In the study group, cups were placed at the predetermined target angles (inclination: 42.5°; anteversion: 15°) with the support of EMN. In the control group, cups were placed freehand aiming at the same target angles. Postoperatively the true position of the cup was determined using computed tomography scan of the pelvis. Precision (root mean squared error, RMSE) bias (mean bias error, ME), accuracy, and duration of surgery were compared between the methods. Results - Cup anteversion was more accurate and precise in the navigated group. The ME in the navigated and freehand group was -1.7° (95% CI -2.4 to 1.1) and -4.5° (CI -6.5 to 2.5), respectively. The RMSE in the navigated and freehand group was 2.8° (CI 2.3-3.2) and 8.0° (CI 6.3-9.5), respectively. The inclination was also more precise in the navigated group, with the RMSE in the navigated and freehand group at 4.6° (CI 3.4-5.9) and 6.5° (CI 5.4-7.5), respectively. The accuracy of the inclination and the duration of surgeries were similar between the groups. Interpretation - Cup placement with the help of EMN is more precise than the freehand technique and it does not affect the duration of surgery.

Does Preoperative Antimicrobial Prophylaxis Influence the Diagnostic Potential of Periprosthetic Tissues in Hip or Knee Infections?

BACKGROUND: Undiagnosed low-grade prosthetic joint infections (PJI) are recognized as an important reason for early failure of presumably aseptic revisions. Preoperatively administered antimicrobial prophylaxis reduces the incidence of PJI but it may reduce the sensitivity of microbiologic periprosthetic tissue cultures and consequently increase the incidence of undiagnosed septic prosthetic joint failures, which can lead to catastrophic serial revisions. QUESTIONS/PURPOSES: We wished to determine whether administration of preoperative antibiotics decreases the likelihood of diagnosing PJI in patients undergoing revision hip or knee arthroplasty in whom infection is suspected. METHODS: We prospectively enrolled and evaluated 40 patients (29 with THAs and 11 with TKAs) who met the following inclusion criteria: older than 18 years, with suspected PJI of unknown cause, undergoing surgical revision. After arthrotomy, three tissue samples were obtained for microbiologic analysis and diagnosis, and antimicrobial prophylaxis (cefazolin 2 g intravenously) then was administered. Later during the procedure, but before débridement and irrigation, the second set of three tissue samples was obtained from the same surgical area and was cultured. Tissue concentration of prophylactic antibiotic was verified with the second set of samples. A positive culture result was defined as one or more positive cultures (growth on agar at or before 14 days). We then compared the yield on the microbiologic cultures obtained before administration of antibiotics with the yield on the cultures obtained after antibiotics were administered. An a priori analysis was performed; with the numbers available, we had 98% power to detect a difference in diagnostic sensitivity of 33%. RESULTS: With the numbers available, we found no difference in the likelihood that an infection would be diagnosed between the samples obtained before and after administration of antimicrobial prophylaxis (odds ratio [OR] for positive microbial culture = 0.99; 95% CI, 0.40-2.48; p = 0.99). All measured tissue concentrations of cefazolin were greater than the minimum inhibitory concentration, therefore we found that antibiotic prophylaxis was adequate at the time of second-set tissue specimen recovery. CONCLUSIONS: Results from this small, prospective series suggest that preoperative antimicrobial prophylaxis may be administered safely even in patients undergoing revision hip or knee arthroplasty in which microbiologic sampling is planned without compromising the diagnostic sensitivity of tissue sample cultures. However, before applying our results more generally, our findings need to be confirmed in larger, multicenter studies that would allow evaluation by sex, procedure, bacteriology, and other potentially important factors. LEVEL OF EVIDENCE: Level I, diagnostic study.

An Upper-Arm Clostridium perfringens Fracture-Related Infection: A Case Report.

CONCLUSION: Fracture-related infections (FRI) pose serious complications, requiring swift surgical intervention. Although C. perfringens infections in FRIs are rare and literature is scarce, this case highlights the successful management and good functional outcome, offering valuable insights for clinicians dealing with such infections.

Bilateral Acrylic Hip Mold Arthroplasty in a Child With a Revision 60 years After Implantation: Clinical Case and Chemical Analysis of Endoprosthetic Material.

A 68-year-old man was referred due to bilateral hip pain and gradual deterioration of walking. He had mold arthroplasties on both hips at the age of 7 years and has been functioning well for more than 5 decades. However, the original data on operative report and the prostheses were missing. The radiological examination revealed bilateral broken prosthetic material. Thus, stage bilateral revision total hip arthroplasty was performed. A detailed chemical analysis of retrieved mold arthroplasty implants proved that the acrylic material was noted to be the same composition with the difference in appearance likely being related to different thermal treatments originally applied to the implants. As presented in our clinical case, even obsolete implants may have good survivorship. According to the case presented, total hip arthroplasty could be considered an effective option with the desired functional outcome when conservative and joint-preserving measures are exhausted.

Acute Femoral Lengthening in Adults Using Step-Cut Osteotomy, Traction Table, and Proximal Femoral Locking Plate Fixation: Surgical Technique and Report of Three Cases.

Introduction: Leg-length discrepancy (LLD) can cause distinct gait and posture disorders that may lead to lifestyle-limiting disability and premature joint degeneration. The purpose of this study was to describe a novel surgical method for acute femoral lengthening in adults with symptomatic structural LLD using step-cut osteotomy, traction table, and proximal femoral locking plate fixation. Materials and methods: We retrospectively evaluated three consecutive adult patients that underwent the procedure at our institution between 2011 and 2019, describing the surgical technique and presenting a report of three cases, including complications assessment. Results: The average age was 47 years (range 38-58), average BMI was 28.1 kg/m2 (range 26.8-29.9), average ASA score was 2 (range 1-3). The mean pre-operative shortening (2 congenital, 1 posttraumatic) was 21 mm (range 20-23). The average elongation achieved was 18 mm (range 15-20). The average surgery duration was 142 min (range 120-165) and the average estimated blood loss was 558 mL (range 375-900). Symptoms were relieved after the lengthening in all three cases. We observed no complications after the mean 68 months (range 22-125) of follow-up. Conclusions: Successful correction of structural LLD is challenging, depends on patient selection, meticulous planning, surgical technique and experience. Therefore, it should be considered case-by-case. In the hands of an experienced surgeon, our method of acute femoral lengthening seems safe and suitable for carefully selected cases of structural LLD correction, where the final lengthening goal remains within the critical limits of one-stage leg lengthening and principles of traction table use.