Deriving reference values for nerve conduction studies from existing data using mixture model clustering

Objective: to obtain locally valid reference values (RVs) from existing nerve conduction study (NCS) data.Methods: we used age, sex, height and limb temperature-based mixture model clustering (MMC) to identify normal and abnormal measurements on NCS data from two university hospitals. We compared MMC-derived RVs to published data; examined the effect of using different variables; validated MMC-derived RVs using independent data from 26 healthy control subjects and investigated their clinical applicability for the diagnosis of polyneuropathy.Results: MMC-derived RVs were similar to published RVs. Clustering can be achieved using only sex and age as variables. MMC is likely to yield reliable results with fewer abnormal than normal measurements and when the total number of measurements is at least 300. Measurements from healthy controls fell within the 95% MMC-derived prediction interval in 97.4% of cases.Conclusions: MMC can be used to obtain RVs from existing data, providing a locally valid, accurate reflection of the (ab)normality of an NCS result.Significance: MMC can be used to generate locally valid RVs for any test for which sufficient data are available.¹     

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.     

Anteromedial minimally invasive plate osteosynthesis (MIPO) for distal third humeral shaft fractures – Is it possible?: A cadaveric study

IntroductionThe purpose of this study was to evaluate the feasibility of the anteromedial minimally invasive plate osteosynthesis (MIPO) approach for distal third humeral shaft fractures and identify neurovascular structures at risk with this approach.MethodsTwenty cadaveric arms were fixed with 12-hole precontoured narrow locking compression plates (LCP) with the anteromedial approach using MIPO technique. The proximal approach was done between the biceps and deltoid muscle directly to the bone. The distal approach involved elevating the brachialis from medial intermuscular septum. The plate was inserted beneath the brachialis tunnel from distal to proximal. Three locking screws were fixed at each end through incisions and the rest of screws were inserted percutaneously. The arms were then dissected to identify damage to or direct contact between the screws and brachial artery (BA), median nerve (MN), musculocutaneous nerve (MCN), and radial nerve (RN). The distances from the screws to structures at risk, humeral length, and length of three distal screws in mediolateral (ML) direction were measured.ResultsThe average humeral length was 28.97 cm. The average danger zone for the BA and MN were 20.47%–62.66% of the humeral length from the lateral epicondyle, and 20.47%-75.02% for the MCN. The ulnar nerve was not endangered by this approach as it lies posteromedially to the humerus. The danger zone for the RN averaged 27.07%–43.74%, and the most dangerous screw that either penetrated or touched the nerve was at the fifth hole, which lay at 33.14% of the humeral length. The average length of three distal screws in ML direction were 41.4, 25.0 and 22.5 mm.ConclusionsThe anteromedial MIPO approach can be performed through the internervous plane beneath the brachialis muscle without exposing any nerves or causing any muscle splitting with a 12-hole plate. Both proximal and distal screw insertion must be done with direct exposure. Insertion of percutaneous screws in the middle part of the plate between the two incisions is not possible. This approach could be an alternative for extra-articular distal third humeral shaft fractures which provides less invasive surgical dissection, allows the use of longer distal screws, and achieves better cosmesis.     

Comparison of screw fixation versus non-fixation in dorsal opening wedge medial cuneiform osteotomy of adult acquired flatfoot

BackgroundThe aim of this study was to compare the radiographic and functional results between fixation and non-fixation in the Cotton osteotomy for the treatment of adult acquired flatfoot.MethodsA retrospective, case-controlled study of consecutive stage IIB posterior tibial tendon dysfunction (PTTD) patients treated with the same bony reconstructive surgery including cotton osteotomy between 2013 and 2017. Meary’s angle, the medial arch sag angle (MASA), and medial cuneiform cobb angle (MCCA) were evaluated pre-operation, at first weight bearing after surgery, and 12 months post operation.ResultsForty feet were included in the study. The cotton osteotomy utilized screw fixation (n = 20) or non-fixation technique (n = 20). No significant differences between groups were found in pre-operative and follow-up radiographic parameters, union rate, and functional results.ConclusionThe non-fixation with press fit technique is a reliable procedure for Cotton osteotomy and as effective as screw fixation.Level of evidenceLevel III, case control study     

Bilateral and concomitant pathology’ surgeries do not affect the outcomes of mini-open distal linear metatarsal osteotomy (Bosch osteotomy) with manipulation for hallux valgus deformity

BackgroundBosch osteotomy for hallux valgus (HV) deformity has advantages of reduction both the operating time and surgical dissection, and may be performed bilaterally and with fewer complications than other surgical procedures as well as early weight-bearing. However, there are few reports on the effects of bilateral simultaneous surgery, simultaneous surgery on concomitant pathologies, and the preoperative HV angle on the postoperative results. The present assessed the factors that might affect the improvement in clinical outcomes following mini-open Bosch osteotomy with manipulation to treat HV deformity.MethodsSeventy patients with 110 feet were included. They were divided into groups as follows: unilateral and bilateral simultaneous surgery groups, Bosch osteotomy alone and simultaneous surgeries for concomitant pathologies groups, and preoperative HV angle< 40° and ≥ 40° groups. Subjective clinical outcome scores using the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) and the HV and intermetatarsal first and second metatarsal (M1M2) angles according to the anteroposterior (A-P) view of the weighted foot X-ray were assessed preoperatively and at 12 months after surgery.ResultsThe mean HV angle, M1M2 angle and all subscales of the SAFE-Q score showed significant improvement at 12 months after surgery, regardless of simultaneous bilateral surgery, simultaneous surgery for concomitant pathologies, or the preoperative HV angle. On comparing the groups, there were no significant differences in the HV angle at 12 months after surgery. Significant inferiority at 12 months after surgery was found in the intermetatarsal angle in the simultaneous surgery for concomitant pathologies group and in all subscales of the SAFE-Q score in the HV angle ≥ 40° group.ConclusionMini-open Bosch osteotomy with manipulation for HV deformity demonstrated good results in both radiological assessments and subjective clinical scores at 12 months after surgery, even for simultaneous bilateral surgery, simultaneous concomitant pathologies’ surgery, and severe HV deformity.Level of EvidencePrognostic Level III, retrospective cohort study.     

运动学对线应用于全膝关节置换术的研究进展

全膝关节置换术是目前治疗终末期膝关节骨性关节炎最有效的方法之一，全膝关节置换术后膝关节功能、术后膝关节疼痛与术后下肢力线有着密切的关系。目前膝关节置换术下肢对线方式主要采用机械力学对线方法，该方法可以改善膝关节功能，但是有部分患者也会产生术后膝关节的疼痛、活动受限等并发症，导致术后患者满意度较差。近些年越来越多的研究开始关注运动力学对线技术并应用于临床。运动学对线技术旨在重建患者的解剖结构，将膝关节假体运动轴与膝关节生理性运动轴保持一致，减少膝关节周围软组织和韧带的松解，实现膝关节生理性运动。该文就运动力学对线方法在全膝关节置换术中的应用进展作一综述。     

Retrograde Instrumentation of Surgically Resected Roots Using Controlled Memory Files: A Human Cadaver Study

IntroductionThe purpose of this study is to evaluate the amount of residual obturation material of retroinstrumented surgically resected roots using controlled memory files and to evaluate the incidence of adverse treatment outcomes.MethodsThirty maxillary anterior teeth in human cadavers were selected, and nonsurgical root canal treatment was performed on these teeth. A standardized 4-mm osteotomy and a 3-mm root resection with as close to 0° bevel as possible were made on each tooth. A microsurgical diamond tip was used to create a 1- to 2-mm starting point for each retropreparation. A 25/06 and 30/06 VTaper 2H were bent at about 90° angle to mimic the clinical and anatomic restrictions and used to create a retropreparation to a depth of 14 mm. Micro–computed tomography scans were taken and analyzed for volume and percentage of residual obturation material at 5 and 10 mm. In addition, the incidences of instrument separation and crack and ledge formation in the teeth were recorded.ResultsThe median volume of residual obturation at 5 and 10 mm was 0.18 mm³ (interquartile range, 0.36 mm³) and 1.97 mm³ (interquartile range, 1.99 mm³), respectively. The overall incidence of file separation during retropreparation was 13.33% (4/30). Among the cases analyzed with micro–computed tomography, none showed crack or ledge formation.ConclusionsRetroinstrumentation of surgically resected roots using controlled memory files cleans the canal effectively with relatively low adverse treatment outcomes. Although this novel technique is limited in application, it is a safe and effective way to achieve a deep, clean retropreparation.