Implant breakage after shoulder arthroplasty: a systematic review of data from worldwide arthroplasty registries and clinical trials.

BACKGROUND: Implant breakage after shoulder arthroplasty is a rare complication after aseptic loosening, infection or persistent pain, resulting in malfunction of the components requiring revision surgery. This correlates with a high burden for the patient and increasing costs. Specific data of complication rates and implant breakage are available in detailed arthroplasty registries, but due to the rare occurrence and possibly underestimated value rarely described in published studies. The aim of this systematic review was to point out the frequency of implant breakage after shoulder arthroplasty. We hypothesized that worldwide arthroplasty registry datasets record higher rates of implant breakage than clinical trials. METHODS: PubMed, MEDLINE, EMBASE, CINHAL, and the Cochrane Central Register of Controlled Trials database were utilized for this systematic review using the items "(implant fracture/complication/breakage) OR (glenoid/baseplate complication/breakage) AND (shoulder arthroplasty)" according to the PRISMA guidelines on July 3rd, 2023. Study selection, quality assessment, and data extraction were conducted according to the Cochrane standards. Case reports and experimental studies were excluded to reduce bias. The breakage rate per 100,000 observed component years was used to compare data from national arthroplasty registries and clinical trials, published in peer-reviewed journals. Relevant types of shoulder prosthetics were analyzed and differences in implant breakage were considered. RESULTS: Data of 5 registries and 15 studies were included. Rates of implant breakage after shoulder arthroplasty were reported with 0.06-0.86% in registries versus 0.01-6.65% in clinical studies. The breakage rate per 100,000 observed component years was 10 in clinical studies and 9 in registries. There was a revision rate of 0.09% for registry data and 0.1% for clinical studies within a 10-year period. The most frequently affected component in connection with implant fracture was the glenoid insert. CONCLUSION: Clinical studies revealed a similar incidence of implant failure compared to data of worldwide arthroplasty registries. These complications arise mainly due to breakage of screws and glenospheres and there seems to be a direct correlation to loosening. Periprosthetic joint infection might be associated with loosening of the prosthesis and subsequent material breakage. We believe that this analysis can help physicians to advise patients on potential risks after shoulder arthroplasty. LEVEL OF EVIDENCE: III.

Does surgical reconstruction of the distal oblique bundle (DOB) provide similar stability as the intact bundle or Adams procedure? A systematic review.

INTRODUCTION: The aim of this review was to summarize the available evidence for biomechanical stability following surgical DOB reconstruction, and to determine whether distal radioulnar joint (DRUJ) stability with a reconstructed DOB was similar to the native intact condition or that after the Adams procedure. MATERIAL AND METHODS: A systematic literature search according to the PRISMA guidelines was performed using the databases PubMed and Embase. The following search algorithm was used: ("DOB" OR "Distal Oblique Bundle") AND "Reconstruction". Biomechanical or human cadaveric studies that measured stability of the DRUJ after reconstruction of the DOB were included. RESULTS: Four articles were included in the final analysis. DOB incidence was reported to be between 50% and 70%. Two studies observed no differences between the intact situation and the reconstructed DOB, respectively the Adams procedure. A further author group found no signs of major instability after the Adams reconstruction or after DOB reconstruction, except for decreased stability during supination in the DOB sample. In another study, similar results could be shown for the Adams and DOB reconstruction groups; however, the DOB sample showed decreased dorsal translation of the radius during forearm supination. CONCLUSION: In conclusion, DOB reconstruction was proven to stabilize the DRUJ adequately. Moreover, the reconstructed DOB showed the same stability as the native DOB, except for one study, in which stability following reconstruction was reduced during supination. No significant difference between the DOB and the Adams reconstruction could be observed.

Two fingerbreadths, one finger's width: on the proximity of the radial nerve to the deltoid tuberosity.

INTRODUCTION: The aim of this study was to find a convenient technique to evaluate the location of the radial nerve (RN) with reference to the deltoid tuberosity (DT). MATERIALS AND METHODS: Sixty-eight upper extremities, embalmed using a modified version of Thiel's method, were included in the study. The interval between the tip of the greater tubercle of the humerus and the distal tip of the lateral humeral epicondyle (LE) was defined as humeral length (HL). The most prominent point of the DT was used as the point of reference. Through this point, a horizontal reference line which met the humeral axis at the dorsal side of the humeral shaft was simulated. The longitudinal distance between the crossing point of the horizontal line and the humeral axis and the RN was measured (distance 1). The interval between the intersection point and the reference point at the DT was measured (distance 2). Data were evaluated in centimeters. RESULTS: For the whole sample, the HL averaged 31.0 cm (SD: 2.3; range 26.2-36.9). Distance 1 averaged 2.2 cm (SD: 0.3; range 1.6-3.1), and distance 2 averaged 1.2 cm (SD: 1.0; range 0-2.8). The HL was larger in the male group when compared to females (p < 0.001; males mean: 32.2 cm; females mean 29.5 cm). There was no difference regarding distance 2 (p = 0.59; males mean: 1.2 cm; females mean: 1.3 cm) between the sexes. Distance 1 was significantly (p = 0.02) larger in the male group (mean: 2.3 cm) when compared to females (mean: 2.1 cm). Concerning sides, there were no differences regarding all evaluated parameters (HL: p = 0.6; Distance 1: p = 0.6; distance 2: p = 0.8). CONCLUSIONS: This study provides an easily applicable technique to localize the RN with reference to the DT.

Emergency approach to the femoral artery.

PURPOSE: The purpose of this study was to evaluate the applicability and potentially associated harms of emergency access to the femoral artery and vein in a sample of physicians working together in the emergency department of a level I trauma center. In addition, to investigate whether there are differences between participants in terms of different levels of training. METHODS: A sample of 36 orthopedic trauma and anesthesiology assistant doctors, specialists, and senior physician was recruited from the emergency room management at a level I trauma center in Graz, Austria. Emergency approach to the femoral vessels was performed on 33 fresh cadavers. Attention was paid to time, successful clamping of the vessels, self-assessment and learning curve. RESULTS: The approach was performed correctly in 97.2% (35/36) of all cases. 97.2% of all participants (35/36) were confident to perform the emergency access. They were proven right, since especially the resident and senior subgroups achieved satisfactory results concerning the correct performance of the approach to the femoral vessels as well as correct identification of the femoral artery and vein. CONCLUSION: In conclusion, we evaluated the emergency access to the femoral artery (FA) and femoral vein (FV) as an easily teachable procedure including high success rates (correct performance in 97.2%).

Lateral para-olecranon approach: surgical guide and anatomical considerations to the anconeus branch: is there a nerve-free zone?

PURPOSE: In the last decades, total elbow arthroplasty, elbow osteosynthesis and revision surgery have been more popularized. The study aimed to assess the course of the anconeus branch of the radial nerve in relation to two variations of the lateral para-olecranon approach, considering iatrogenic nerve injuries. METHODS: The study consisted of 120 upper extremities from 60 Thiel-embalmed human specimens. Two randomized versions of the lateral para-olecranon approach (centrally orientated: P1 and laterally orientated: P2) were performed. The olecranon and the intersection points to the anconeus branch of the radial nerve were determined as anatomical landmarks. The measurements were assessed by two independent observers. Differences were analyzed using the Student's t test; associations were computed with the Pearson correlation (r). An alpha of 0.05 (p) and a confidence interval of 95% were set. RESULTS: The intersection points averaged 12.3 cm (SD 1.8, range 8.2-16.8) for P1 versus 5.5 cm (SD 1.4, range 3.0-9.2) for P2 (p ≤ 0.001). Statistically significantly higher values for male and longer humeral specimens were revealed (all values: p < 0.05). Comparison of left and right sides yielded no difference. Excellent inter-rater agreements were found (ICC = 0.902, range 0.860-0.921). A correlation was evaluated between the humeral length and the distances in both approaches (P1: r = 0.550, p < 0.001, P2: r = 0.669, p < 0.001). CONCLUSION: The data presented here allow preservation of the anconeus branch. The P1 forms a potential advantage by owing a broader safe zone. Using the centrally orientated approach seems to provide adequate nerve protection during surgery for one of the motor branches for extension of the elbow joint and might result in improved postoperative benefits.

Direct anterior versus antero-lateral approach in hip joint hemiarthroplasty.

BACKGROUND: Femoral neck fractures are common injuries in the elderly and represent a major source of morbidity and mortality. Due to the benefits, bipolar hip hemiarthroplasty (BHH) is a popular method to treat. The purpose of this study is to evaluate the functional and radiographic outcomes for BHH comparing the direct anterior approach (DAA) to the anterolateral approach (ALA) to the hip joint. METHODS: We used a prospective, randomized observational study design, where we enrolled 83 patients at a level-I-trauma center presenting with indication for BHH. We followed up the participants at defined intervals over a period of 1 year. The follow-up examinations were carried out at defined time intervals for a period of 1 year. Calculations were performed with Statistical Package for Social Sciences (SPSS) 21.0. RESULTS: Concerning postoperative pain sensation, the anterior group had statistically significantly decreased pain levels at one (p = 0.02), seven (p = 0.04) and 14 days (p = 0.02) following the intervention when compared to the ALA sample. The postoperative modified Barthel-Index showed a statistically significant difference on the first postoperative day at the anterior group. CONCLUSION: Although we compared two minimally invasive approaches, our results shows a statistically significant difference in pain intensity and mobility for the early postoperative period using the direct anterior approach.

Proportional localisation of the entry point of the coracobrachialis muscle by the musculocutaneous nerve along the humerus.

PURPOSE: To project the distance between the tip of the greater tubercle (GT), respectively, the proximal border of the tip of the coracoid process (CP) and the entry point of the coracobrachialis by the musculocutaneous nerve (MCN) proportionally onto the humeral length. METHODS: Sixty-six upper extremities were included in the study. The distance between the tip of the GT and the distal tip of the lateral humeral epicondyle (LE) was evaluated as the humeral length (HL). The interval between the tip of the GT and the entry point of the coracobrachialis muscle by the MCN was measured. The distance between the proximal border of the tip of the CP and the distal portion of the medial humeral epicondyle (ME) and the entry point of the MCN into the coracobrachialis were evaluated. Proportions were used to project the entry point of the coracobrachialis by the MCN along the HL, respectively, the interval between the proximal border of the tip of the CP and the distal tip of the ME. RESULTS: The entry point of the MCN into the coracobrachialis muscle can be expected at an interval between 14.9 and 33.9% of the HL (between the tip of the GT and the LE), starting from the tip of the GT. Regarding the reference line between the proximal border of the CP and the ME, the nerve's entry point was located between 14.2 and 34.4%, starting from the CP. CONCLUSION: Results represent easily applicable intervals for intraoperative localisation of the MCN.

Mini-open carpal tunnel release: technique, feasibility and clinical outcome compared to the conventional procedure in a long-term follow-up.

We sought to evaluate the findings of our anatomically landmarks based mini-open procedure (MCTR) through a palmar approach and to compare its outcome and practicability to the conventional method (OCTR). The study consisted of 100 matched patients (n = 50 MCTR, n = 50 OCTR) with a minimum follow-up of three years. The outcome was characterized via the Disabilities of Arm, Shoulder and Hand Score (DASH), Symptom Severity Scale (SSS), Functional Status Scale (FSC), and Visual Analogue Scale (VAS). All adverse events were observed. An alpha of 0.05 and a confidence level of 95% were set for statistical analyses. Both techniques showed comparable functional results in a long-term period (mean follow-up MCTR: 60 months and OCTR: 54 months). MCTR versus OCTR at mean: DASH: 4.6/8.3 (p = 0.398), SSS: 1.3/1.2 (p = 0.534), FSC: 1.3/1.2 (p = 0.617), VAS: 0.4/0.7 (p = 0.246). The MCTR convinced through a lower rate of scar sensibility (MCTR: 0% vs. OCTR: 12%, 0/50 vs. 6/50; p = 0.007) and pillar pain, as well as a shortened recovery period and surgical time relative to the OCTR. Low complication rates were observed in both groups, no recurrences had to be documented. The MCTR procedure revealed a similar good clinical outcome as the conventional technique. MCTR is a minimally-invasive, reliable, fast and simple procedure with an obvious benefit regarding scar sensibility.

Dorsal minimally invasive plate osteosynthesis of the humerus: Feasibility and risk of nervous injury of a modified technique in an anatomical study.

BACKGROUND: The aim of the study was to design a convenient technique for dorsal minimally invasive plate osteosynthesis (MIPO) of extra-articular fractures of both distal thirds of the humeral shaft as well as to characterise the course and proximity of the radial nerve (RN) and the axillary nerve (AN). METHODS: The collective consisted of 20 upper extremities of human adult body donors. A 3.5 mm Locking Compression Plate (LCP), an extra-articular distal humerus plate was inserted through a MIPO approach including two incisions. The primary incision was performed 5 cm in lenght on the dorsal side of the lateral epicondyle. An additional 5 cm incision was conducted distal to the humeral deltoid muscle insertion and the RN was depicted. The longest suitable plate was advanced under nerve protection starting distally and fixed by locking screws. A third incision with a length of 5 cm was made beginning at the distal border of the deltoid muscle, and a muscle split was performed to dissect the AN. The respective plate holes, where the AN and RN were located and the distances between the nerves were examined. RESULTS: The RN was mostly (30%) localised on holes 6 and 7 (starting distally). The AN laid directly on the plate in 65% and on the most proximal plate hole in 12 cases, but was never situated underneath the plate. The distance between the AN and RN was at mean 93.5 mm. CONCLUSIONS: MIPO via a dorsal method proves to be a noteworthy technique and valuable option as indicated by our results. This 5-5-(5) concept may be performed as a two-incision or three-incision technique for extra-articular fractures of both distal thirds of the humerus.

All-arthroscopic reconstruction of the anterior talofibular ligament is comparable to open reconstruction: a systematic review.

The aim of this study was to determine whether all-arthroscopic repair would lead to improved clinical outcomes, lower complication rates, shorter postoperative immobilization and earlier return to activity compared to open Broström repair in the surgical treatment of chronic lateral ankle instability (CLAI). A systematic literature search was conducted using Pubmed and Embase to identify studies dealing with a comparison of outcomes between all-arthroscopic and open Broström repair for CLAI. The search algorithm was 'ankle instability' AND 'Brostrom' AND 'arthroscopic' AND 'open'. The study had to be written in English language, include a direct comparison of all-arthroscopic and open Broström repair to treat CLAI and have full text available. Exclusion criteria were former systematic reviews, biomechanical studies and case reports. Overall, eight studies met the inclusion criteria and were included in the analysis. Clinical outcomes did not differ substantially between patients treated with either arthroscopic or open Broström repair. Studies that reported on return to activity and sports following surgery suggested that patients that had all-arthroscopic Broström repair returned at a quicker rate. Overall complication rate tended to be lower after arthroscopic Broström repair. Similar to open repair, all-arthroscopic ligament repair for CLAI is a safe treatment option that yields excellent clinical outcomes. Level of Evidence: Level III evidence (systematic review of level I, II and III studies).

Minimally invasive plate osteosynthesis of the humeral shaft with regard to adjacent anatomical characteristics.

The study goal was to evaluate the distances from the radial (RN), the musculocutaneous (MN) and axillary nerves (AN) and the medial neurovascular bundle of the upper arm to a minimally invasive applied plate and to define its relation to the RN during different degrees of malrotation during MIPO. The sample involved ten upper extremities. Application of a PHILOS plate was performed through a Delta-split. Intervals between the AN, MN, RN and the medial vascular bundle were defined at various positions. The humeral shaft was artificially fractured at a height of about the mean of the plate. The distal fragment was brought into 15° and 30° internal (IR) as well as external rotation (ER) and here, the plate's relation to the RN was evaluated. The medial neurovascular bundle intersected the plate at its distal part in two specimens. Regarding the distances from the RN to the plate during different rotation positions the distances became significantly longer during ER, respectively shorter during IR. The medial neurovascular bundle and the RN were identified as the main structures at risk. Care must be taken during distal screw placement and malrotation exceeding 15° must be avoided during MIPO.

Danger zone - The spermatic cord during anterior plating of the symphysis pubis.

BACKGROUND: Distances between anatomic landmarks and anatomic structures at risk are often underestimated by surgeons. PURPOSE: The goal of the study was to evaluate the distances between anatomic landmarks and the spermatic cord in case of anterior plating of the symphysis. METHODS: A total of 25 pelves (50 hemipelves) of male embalmed cadavers were dissected. A 5-hole 3.5mm locking compression plate (Synthes GmbH) was fixed from directly anterior on the symphysis. Measurements were taken 1) distance between the tips of both pubic tubercles, 2) horizontal interval between the lateral border of the plate and the medial margin of the SC (bilateral), 3) distances between the medial border of the SC and the tip of the pubic tubercle (bilateral), 4) distances between the medial border of the SC and the lateral basis of the pubic tubercle (bilateral). RESULTS: The distance between the pubic tubercles was 60.3mm in average (SD: 5.7). The interval between the lateral border of the plate and the medial margin of the SC was on average 4.5mm (SD: 1.9) on the right and 4.7mm (SD: 2.6) on the left side. The distance between the tip of the pubic tubercle and the medial border of the SC was in average 11.2mm (SD: 2.7) on the right, and 11.0mm (SD: 2.7) on the left side. The average distance between the medial border of the SC and the lateral basis of the pubic tubercle was 8.1mm (SD: 2.4) on the right and 8.2 mm (SD: 2.4) on the left side. CONCLUSION: The SC is at risk not only during dissection but also during anterior plating of the symphysis, because of its close relation to the SC. CLINICAL RELEVANCE: Average distances between the palpable pubic tubercle and the SC are below one finger breadth (as reference).

Improved Outcome and Earlier Return to Activity After Suture Tape Augmentation Versus Broström Repair for Chronic Lateral Ankle Instability? A Systematic Review.

PURPOSE: To determine whether the use of suture tape augmentation (ST) would lead to improved clinical outcomes, increased stability, shorter postoperative immobilization, and earlier return to activity and sports compared with Broström repair (BR) in surgical treatment of chronic lateral ankle instability (CLAI). METHODS: A systematic literature search was performed using Pubmed and Embase according to PRISMA guidelines. The following search terms were used: ankle instability, suture tape, fiber tape, and internal brace. Full-text articles in English that directly compared BR and ST cohorts were included, with a minimum cohort size of 40 patients. Exclusion criteria were former systematic reviews, biomechanical studies, and case reports. RESULTS: Ultimately, 7 clinical trials were included in this systematic review. Regarding the clinical and radiologic outcomes and complication rates, no major differences were detected between groups. Recurrence of instability and revision surgeries tended to occur more often after BR, whereas irritation of the peroneal nerve and tendons seemed to occur more frequently after ST. Postoperative rehabilitation protocols were either the same for both groups or more aggressive in the ST groups. When both techniques were performed with arthroscopic assistance, return to sports was significantly faster in the ST groups. CONCLUSIONS: In conclusion, suture tape augmentation showed excellent results and is a safe technique comparable to traditional Broström repair. No major differences regarding clinical and radiologic outcomes or complications were found. LEVEL OF EVIDENCE: III, systematic review of level I, II, and III studies.

Relation of the lumbosacral trunk to the sacro-iliac joint.

This study aims to evaluate the relation between the lumbosacral trunk (LT) and the sacro-iliac joint (SIJ). In forty anatomic specimens (hemipelves) a classical antero-lateral approach to the SIJ was performed. The SIJ was marked at the linea terminalis (reference point A). Reference point B was situated at the upper edge of the interosseous sacro-iliac ligament. The length of the SIJ (distance A to B) and the distance between point A and the ventral branch of the fourth (L4) and fifth (L5) lumbar spinal nerves at the linea terminalis were measured. The SIJ had a mean length of 58.0 mm. The ventral branch of L5 was located closer to the SIJ in very long SIJs (mean length: ≥ 6.5 cm; mean distance: 9.8 mm) compared to very short joints (≤ 5 mm; mean distance: 11.3 mm). For the ventral branch of L4, very long SIJs had a mean distance of 7 mm and very short joints an average distance of 9.7 mm between point A and the nerve branch. A safe zone of approximately 1 cm to 2 cm (anterior to posterior) is present on the sacral surface (lateral to medial) for safe fixation of plates during anterior plate stabilization of the SIJ. Pelves with a shorter dorsoventral diameter of the most superior part of the SIJ apparently give more space for inserting plates.

In vitro testing of silver-containing spacer in periprosthetic infection management.

Deep infection is a serious complication in endoprosthetic surgery. In correlation to the patient local or systemic compromising factors conservative and surgical proceedings has to be evaluated. Systemic antibiotic therapy is the gold standard in infection management. Implanted silver-coated or silver-containing medical devices have been proven to their antimicrobial effectiveness since the 1990s by several investigators. The outcomes showed that long time implantation could cause damaging of the surrounding tissues, especially of adjacent nerves. The aim of our study was to evaluate the release of silver (I) ions from bone cement mixed with either nanosilver particles (AgNPs), different concentrations of silver sulfate (Ag2SO4) or from pure metallic silver strips. Therefore, we choose two methods: the first, called "static model", was chosen to evaluate the maximal accumulative concentration of silver (I) ions, with the second, called "dynamic model", we simulated a continuous reduction of the ions. In an additional test design, the different materials were evaluated for their antimicrobial activity using an agar gel diffusion assay. The outcome showed that neither the addition of 1% (w/w) nanosilver nor 0.1% silver sulfate (w/w) to polymethylmethacrylat bone cement has the ability to release silver (I) ions in a bactericidal/antifungal concentration. However, the results also showed that the addition of 0.5% (w/w) and 1% (w/w) silver sulfate (Ag2SO4) to bone cement is an effective amount of silver for use as a temporary spacer.

Projection of the A1-Pulley of the Thumb onto Superficial Anatomical Landmarks: An Anatomical Study and a Useful Guide to Surgeons.

BACKGROUND: The aim of our study was to project the A1-pulley of the thumb onto the total thumb length to enable its complete division with and without direct sight. MATERIALS AND METHODS: The study involved 50 hands from adult human cadavers. The proximal and distal borders of the A1-pulley were measured with reference to the first metacarpophalangeal joint (MCPJ). The length of the thumb was defined as the interval between the first carpometacarpal joint (CMCJ) and the apex of the thumb. The length of the pulley is calculated proportionally with reference to the line between the first CMCJ and apex of the thumb. RESULTS: Approximated by computing 95% confidence intervals, the pulley can be expected to lie in an area between 34.0% (proximal border) and 57.8% (distal border) alongside this line. CONCLUSION: Percutaneous and minimally-invasive division of the A1-pulley needs to be performed between 34.0 and 57.8% of the length between the first CMCJ and apex of the thumb.

Definition of a Risk Zone for the Axillary Nerve Based on Superficial Landmarks.

BACKGROUND: The aim of this study was to investigate the axillary nerve's location along superficial anatomical landmarks, and to define a convenient risk zone. METHODS: A total of 123 upper extremities were evaluated. After dissection of the axillary nerve, the vertical distance between the upper border of the anterolateral edge of the acromion and the proximal border of the nerve was measured. Furthermore, the interval between the proximal border and the distal border of the axillary nerve's branches was evaluated. The interval between the distal border of the branches and the most distal part of the lateral humeral epicondyle was measured. The distance between the anterolateral edge of the acromion and the lateral humeral epicondyle was evaluated. Measurements were expressed as proportions with respect to the distance between the acromion and the lateral humeral epicondyle. RESULTS: The distance between the acromion and the proximal border of the axillary nerve's branches was at a height of 10 percent of the distance between the acromion and the lateral humeral epicondyle, starting from the acromion (90 percent when starting from the lateral humeral epicondyle). The interval between the proximal and distal margins of the axillary nerve's branches was between 10 percent and 30 to 35 percent of this interval, starting from the acromion (65 to 70 percent when starting from the lateral humeral epicondyle). CONCLUSIONS: The authors were able to locate the branches of the axillary nerve at an interval between 10 and 35 percent of the distance between the acromion and the lateral humeral epicondyle, starting from the acromion. This makes the proximal third of this distance an easily applicable risk zone during shoulder surgery.

Optimal pin position in supraacetabular external fixation.

BACKGROUND: This study focuses on (i) the length of the intraosseous part of the supraacetabular pin using the insertion technique from the spina iliaca anterior inferior to the cortical part of the incisura ischiadica major, (ii) the angle of insertion of the supraacetabular pin in the transversal plane and (iii) gender-specific differences of the measured results. METHODS: Images of uninjured pelves from 49 patients (64-line computed tomography scanner) were evaluated, and virtual external fixator pins were positioned using a three-dimensional reconstructions of computed tomography scans. The length of the pins and the insertion angle were investigated. Descriptive statistics were used, and gender-specific differences were calculated. A P-value of <0.05 was considered statistically significant. RESULTS: The results showed significant differences between male and female pelves concerning both pin length and insertion angel. For male pelves, the mean screw length was 82.7 mm (SD 5.1; range 72.9-94.3). For females, this was statistically significantly shorter (P ≤ 0.001), with an average of 74.1 mm (SD 5.0; range 63.1-81.9). In the male subgroup, the insertion angle was a mean of 22.6° (SD 3.4; range 12.4-31.8), and the female pelves had an average angle of 19.7° (SD 4.0; range 11.7-24.5). These values differed statistically significantly (P = 0.0032). CONCLUSION: Based on our measurements, we can confirm that both the length of the Schanz screws and the angle of insertion for the supraacetabular external fixator show a statistically significant difference between males and females.

A novel method of clinical first tarsometatarsal joint hypermobility testing and radiologic verification.

BACKGROUND: First tarsometatarsal joint (TMT-1) hypermobility might cause hallux valgus deformity (HV), and recurrence following surgical correction. Anatomic findings, indicating tibialis anterior tendon (TAT) involvement in TMT­1 stabilization, led to the development of cross-glide test allowing clinical TMT­1 stability testing. Cross-glide test function was evaluated in anatomical specimens and in the clinical setting, compared to simulated weight-bearing computer tomography (CT) analysis. METHODS: Cross-glide test was evaluated in 6 healthy lower leg specimens before and after TAT transection. Clinical testing was performed prospectively in 36 feet (6 controls, 21 HV, 9 recurrent HV); consecutive weight-bearing CT analysis was performed. Results from clinical testing were compared to CT analysis. RESULTS: TMT­1 instability significantly increased in anatomic specimens following TAT transection (p = 0.009). In the clinical setting, all healthy feet were cross-glide test negative, 62% of HV cases and all recurrent HV feet were positive. In the CT analysis- Compared to controls the HV cases revealed significantly increased MT­1 internal rotation (p = 0.003) and decreased dorsal angle (p = 0.002), considered as collapsing forefoot signs; HV recurrent cases revealed similar results. Positive cross-glide tested cases revealed increased MT­1 internal rotation values (p < 0.001) and dorsal angle values (p < 0.001) in CT analysis. Strikingly, cross-glide test positive HV cases revealed significantly increased internal TMT­1 rotation (p = 0.043) in CT analysis, and HV and IMT (intermetatarsal) angle were significantly higher (p = 0.005, p = 0.006). 15 HV recurrence cases, treated with TMT­1 arthrodesis, revealed no recurrence during follow-up. CONCLUSION: Cross-glide test allows reliable clinical TMT­1 instability testing, via TAT tension, and is less laborious than CT analysis. We recommend TMT­1 arthrodesis in cases with instability in clinical testing, to avoid HV recurrence.

Evaluation of screw placement in proximal humerus fractures regarding drilling manoeuvre and surgeon's experience.

INTRODUCTION: Following proximal humeral plate osteosynthesis, mechanical complication rates ranging up to 40% have been reported. The study aims to determine the influence of surgeons' experience and the technique of drilling on the complication rate. MATERIALS AND METHODS: The sample involved 45 cadaveric humeri. Six orthopaedic surgeons were divided into two groups with regard to their level of experience (novice versus expert group). On each humerus two different proximal humerus plates were applied. Drillings were performed either with a sharp or worn drill bit (to simulate either sharp or blunt drilling). The respective holes were drilled until the respective participant thought to have placed the drill bit subchondrally, followed by perforation of the cartilage of the humeral head. Both these values and cases of unintended penetration of the articular cavity were evaluated. RESULTS: Fourteen holes (3.6%) were primary penetrated in the joint cavity in the worn-drill-bit-subgroup and 19 holes (5%) in the sharp-drill-bit-group. The latter had an average distance between the chosen subchondral position and the humeral articular surface of 8.3 mm and the worn-drill-bit-subgroup was at 10.6 mm. In the novice group 20 perforations (5.2%) of the joint space occurred and the mean interval between the chosen subchondral point and the humeral articular surface was 4.0 mm. The experienced surgeons showed a perforation rate of 3.4% and were at a mean of 14.9 mm. There were no significant differences regarding drilling manoeuvres and experience. CONCLUSION: Although our results are satisfactory, they can be traced back to the relatively high interval between the respective chosen position of the drill bit and the humeral articular surface which may not guarantee screw stability during ORIF of all fracture patterns.