Faster bone union progression and less sclerosis at the osteotomy margin after medial opening-wedge high tibial osteotomy using highly porous β-tricalcium phosphate granules versus allogeneic bone chips: A matched case–control study

BackgroundThis study compared bone union progression using highly porous (80% porosity) β-tricalcium phosphate (β-TCP) granules or allogeneic bone chips in the gap created by medial opening-wedge high tibial osteotomy (MOWHTO).MethodsThe study population consisted of 54 patients who received MOWHTO with locking plate fixation: 27 patients using highly porous β-TCP granules, and 27 age- and sex-matched patients using allogeneic bone chips. Bone union progression was evaluated 1, 3, 6, and 12 months postoperatively. The presence of radiographic sclerosis at the osteotomy margin was also assessed.ResultsAmong all patients, the highest degree of bone union observed 12 months postoperatively was grade 4. As postoperative time passed, bone union progression of highly porous β-TCP granules increased linearly and was statistically significant compared with that of cancellous allogeneic bone chips (P = 0.014). The presence of radiographic sclerosis at the osteotomy margin was significantly less common in the β-TCP group than in the allograft group (P = 0.003) and was the strongest predictor of delayed progress of bone union (odds ratio = 6.16, P = 0.006).ConclusionsPatients who underwent MOWHTO using highly porous β-TCP granules had faster new bone remodeling, less radiographic sclerosis at the osteotomy margin, and no inferior clinical outcome compared with allogeneic bone chips, as determined at the 1-year follow up. The presence of radiographic sclerosis at the osteotomy margin in patients undergoing MOWHTO using allogeneic bone or synthetic bone substitute may indicate delayed progress of bone union.     

Correlation study of increase of pharyngeal airway space after mandibular advancement,taking natural head position into consideration

The increase in the pharyngeal airway space after mandibular advancement has not been well explained, and in this study we aimed to show whether there is a correlation in the increase of pharyngeal airway space as a consequence of the mandibular advancement or of the relative change between the mandibular position and the natural head position (NHP). Fifteen patients who had bilateral sagittal split osteotomy for mandibular advancement with or without genioplasty were studied retrospectively. The primary variables of mandibular position, NHP, and pharyngeal airway space were measured in three dimensions using preoperative and postoperative cone-beam computed tomographic datasets and were compared using the paired t test. The secondary variable of pharyngeal airway space was defined as the square root of the mean cross-sectional area (CSA^1/2) of the pharyngeal airway space. Pearson’s correlation coefficient was used to find out whether there was a correlation between the change in CSA^1/2 and the change in mandibular position, or the relative change between the mandibular position and the NHP. Volumes and minimal cross-sectional areas were increased in the pharyngeal airway space, and lengths of airways decreased. Correlation existed only between the increase in CSA^1/2 and the relative change between the mandibular position and NHP. The increase in pharyngeal airway space after mandibular advancement correlated with the relative changes between the mandibular position and the NHP.     

Does the stabilization of the calcaneocuboid joint with Steinmann pin in Evans osteotomy affect its incidence of arthritis?

PurposeThis study aims to determine the effect of retaining a Steinmann pin in the calcaneocuboid joint on its rates of arthritis following Evans calcaneal osteotomy lengthening procedure. The study hypothesized that leaving the pin across the calcaneocuboid joint post-operatively would lead to higher rates of arthritis.MethodsThis is a retrospective review of patients under 18 years of age who underwent Evans osteotomy at our hospital from January 2015 to May 2020. The Patients were stratified into 2 groups: Group 1 (pin was left post-operatively across the joint and removed on follow-up) and Group 2 (pin was removed during surgery). Demographic data were recorded, including age, sex, and body mass index. Calcaneocuboid arthritis was determined by radiographic imaging at least one-year follow-up. Time to pin removal, size of the pin and graft, and subluxation were analyzed as possible risk factors for arthritis. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated.Results39 patients were included in the study: 24 patients had the pin removed post-operatively, and 15 had the pin removed intra-operatively. There were no significant differences between the 2 groups regarding body mass index, age, sex, or laterality. Calcaneocuboid arthritis rates were significantly higher in the Group 1 than Group 2 (12(50%) vs. 2(13.3%), respectively; p = 0.02). On multivariate regression, both age (OR, 1.305 [95%CI: 1.009−1.696]; p = 0.044) and leaving the pin in the joint postoperatively (OR, 7.661 [95%CI: 1.208−48.570]; p = 0.031) were found as risk factors for arthritis at follow-up. The mean time to pin removal, the size of the pin, and the size of the graft were not found to be significant predictors of arthritis (p > 0.05).ConclusionsThis study shows that leaving the Steinmann pin in the calcaneocuboid joint in children post-operatively is associated with an increased risk of developing early radiographic signs of calcaneocuboid joint arthritis.     

The percutaneous learning curve of 3rd generation minimally-invasive Chevron and Akin osteotomy (MICA)

BackgroundMinimally-invasive Chevron and Akin osteotomy (MICA) represents the third-generation percutaneous hallux valgus surgery which is characterized by an extra-articular osteotomy, stable internal fixation and a high potential for correction. Compared to other percutaneous techniques of the foot, MICA is generally regarded as an advanced and demanding surgical procedure with a flat learning curve. The aim of this study is to analyze a single-surgeons experience with his first 50 consecutive MICA procedures.MethodsBetween May 2018 and February 2021, 50 consecutive MICA procedures performed by the author with the "K-wires-First technique" were prospectively analyzed focusing on surgery duration, number of fluoroscopies, correction results and surgery-associated complications. A modification of the original MICA technique as described by its inaugurators Redfern and Vernois allows the use of a standard-sized C-arm and aims to reduce revison rates and conversion to open surgery by placing the guidewires prior to performing the osteotomy.ResultsThe average surgery time for all MICA procedures was 46.8 min (SD 12.1, range 31–90 min). The average amount of fluoro shots required to perform MICA was n = 126.6 (SD 40.8, range 65–231). Comparing the preoperative and 6-week postoperative radiographs, the IMA decreased after MICA by a mean of 10.8° from 16.2° to 5.4° and the HVA by a mean of 22.1° from 30.6° to 8.5°. One case required intraoperative conversion to open hallux correction. There were 4 feet in three patients with secondary screw removal of the Chevron fixation due to prominent proximal screw tips.ConclusionsAlthough the learning curve of 3rd generation MICA is flat and requires specific training and intensive practice, the rate of complications is not elevated compared to other percutaneous hallux valgus techniques. Strict adherence to the principles of 3rd generation MICA with stable fixation and meticulous intraoperative control of each surgical step helps to reduce surgery-associated complications. The learning curve showed a continous improvement in regard to surgery time and use of fluoroscopy. After 40 procedures, the surgery time consistently dropped under 45 min and required less than 100 fluoro-shots. The modified surgical technique may help reduce Chevron screw mal-positioning when using large C-arm fluoroscopy for this procedure.