Der Einfluss von Ellenbogenpositionierung und Gelenkinsufflation auf die Lage der Nn. medianus und radialis - eine dreidimensionale bildgestützte Analyse

In der vorliegenden Untersuchung wurden die Lageverhältnisse des N. medianus und N. radialis zu den ossären Strukturen des Ellenbogens bestimmt. Außerdem wurde der Einfluss der Ellenbogen- und Unterarmpositionierung sowie der Gelenkinsufflation untersucht. Die Lagekenntnis der beiden Nerven sind insbesondere bei der Durchführung einer anterioren Kapsulektomie von Bedeutung. Der N. medianus wurde vor dem medialen Viertel der Trochlea humeri gesehen, kann jedoch auch in einigen Fällen medial der Trochleagrenze liegen. Bei der Kapsulektomie des medialen Teils der anterioren Gelenkkapsel muss dies beachtet werden. Der N. radialis medialisiert durch 90° Flexion des Ellenbogens von seiner Lage vor der medialen Grenze des Capitulum humeri in Extension zum medialen Rand des Capitulums. Dieses Wissen kann genutzt werden, um durch eine Extension des Ellenbogens bei der Kapsulektomie vor dem lateralen Rand der Trochlea humeri und eine Flexion während der Kapsulektomie des lateralen Teils der Gelenkkapsel das Verletzungsrisiko des N. radialis zu verringern. Zusätzlich wurde eine Verdopplung der Abstände des N. medianus und des N. radialis zur anterioren Begrenzung der knöchernen Strukturen von Extension auf 90° Ellenbogenflexion sowie eine Verdreifachung nach zusätzlicher Gelenkinsufflation mit 20 ml Flüssigkeit beobachtet. Dies lässt auf ein erhöhtes Risiko iatrogener Nervenverletzungen bei der arthroskopischen Ellenbogenarthrolyse von Patienten mit Arthrofibrose schließen, da bei diesen Patienten die Möglichkeit der Gelenkinsufflation des Ellenbogens reduziert sein kann

Treatment strategies for simple elbow dislocation - a systematic review

Abstract Background Current treatment concepts for simple elbow dislocation involve conservative and surgical approaches. The aim of this systematic review was to identify the superiority of one treatment strategy over the other by a qualitative analysis in adult patients who suffered simple elbow luxation. Study design A systematic review in accordance with the PRISMA guidelines and following the suggestions for reporting on qualitative summaries was performed. A literature search was conducted using PubMed and Scopus, including variations and combinations of the following keywords: elbow, radiohumeral, ulnohumeral, radioulnar, luxation, and therapy. Seventeen studies that performed a randomized controlled trial to compare treatment strategies as conservative or surgical procedures were included. Reviews are not selected for further qualitative analysis. The following outcome parameters were compared: range of motion (ROM), Mayo Elbow Performance Score (MEPS), Disabilities of the Arm, Shoulder and Hand outcome measure (Quick-DASH), recurrent instability, pain measured by visual analog scale (VAS) and time to return to work (RW). Results Early mobilization after conservative treatment strategies showed improved ROM compared to immobilization for up to 3 weeks after surgery with less extension deficit in the early mobilization group (16° ± 13°. vs. 19.5° ± 3°, p < 0.05), as well as excellent clinical outcome scores. Surgical approaches showed similar results compared to conservative treatment, leading to improved ROM (115 vs. 118 ± 2.8) and MEPS: 95 ± 7 vs. 92 ± 4. Conclusion Conservative treatment with early functional training of the elbow remains the first-line therapy for simple elbow dislocation. The surgical procedure provides similar outcomes compared to conservative treatment regarding MEPS and ROM for patients with slight initial instability in physical examination and radiographs. People with red flags for persistent instability, such as severe bilateral ligament injuries and moderate to severe instability during initial physical examination, should be considered for a primary surgical approach to prevent recurrent posterolateral and valgus instability. Postoperative early mobilization and early mobilization for conservatively treated patients is beneficial to improve patient outcome and ROM

The risk of suprascapular and axillary nerve injury in reverse total shoulder arthroplasty: An anatomic study

Purpose: Implantation of a reverse total shoulder arthroplasty (rTSA) places the axillary and suprascapular nerves at risk. The aim of this anatomic study was to digitally analyse the location of these nerves in relation to bony landmarks in order to predict their path and thereby help to reduce the risk of neurological complications during the procedure. Methods: A total of 22 human cadaveric shoulder specimens were used in this study. The axillary and suprascapular nerves were dissected, and radiopaque threads were sutured onto the nerves without mobilizing the nerves from their native paths. Then, 3D X-ray scans of the specimens were performed, and the distance of the nerves to bony landmarks at the humerus and the glenoid were measured. Results: The distance of the inferior glenoid rim to the axillary nerve averaged 13.6 mm (5.8-27.0 mm, +/- 5.1 mm). In the anteroposterior direction, the distance between the axillary nerve and the humeral metaphysis averaged 8.1 mm (0.6-21.3 mm, +/- 6.5mm). The distance of the glenoid centre to the suprascapular nerve passing point under the transverse scapular ligament measured 28.4 mm (18.9-35.1 mm, +/- 3.8 mm) in the mediolateral direction and 10.8 mm (+/- 4.8 to 25.3 mm, +/- 6.1 mm) in the anteroposterior direction. The distance to the spinoglenoid notch was 16.6 mm (11.1-24.9 mm, +/- 3.4 mm) in the mediolateral direction and +/- 11.8 mm posterior (+/- 19.3 to +/- 4.7 mm, +/- 4.7 mm) in the anteroposterior direction. Conclusions: Implantation of rTSA components endangers the axillary nerve because of its proximity to the humeral metaphysis and the inferior glenoid rim. Posterior and superior drilling and extraosseous screw placement during glenoid baseplate implantation in rTSA place the suprascapular nerve at risk, with safe zones to the nerve passing the spinoglenoid notch of 11 mm and to the suprascapular notch of 19 mm. (C) 2017 Elsevier Ltd. All rights reserved

Annular ligament reconstruction with the superficial head of the brachialis: surgical technique and biomechanical evaluation

The purpose of this study was to perform biomechanical testing of annular ligament (AL) reconstruction using the superficial head of the brachialis tendon (SHBT) as a distally based tendon graft. We hypothesized that posterior translation of the radial head following AL reconstruction with an SHBT graft does not significantly differ from intact specimens. Six fresh-frozen elbow specimens were used. The stability of the radial head against posterior translation forces (30 N) was evaluated in 0A degrees, 45A degrees, 90A degrees and 120A degrees of elbow flexion. Posterior translation was obtained for the intact AL, the sectioned AL and the reconstructed AL. Cyclic loading (100 cycles) in 90A degrees of elbow flexion was performed for the intact and the reconstructed AL. Posterior translation of the radial head decreased during elbow flexion in native specimens. Sectioning of the AL significantly increased instability over the full range of motion. AL reconstruction with the SHBT restored the stability of the proximal radius but-other than the native AL-was not influenced by elbow flexion. In 120A degrees of flexion the native AL provided significantly more stability when compared to the reconstructed AL. Cyclic loading did not provide significant differences between native and reconstructed specimens. We provide a feasible technique for AL reconstruction using the SHBT. The biomechanical results obtained in this study confirm the efficacy of the procedure. AL reconstruction restores the stability of the proximal radius, yet it cannot fully mimic the complex features of the intact AL

Elbow Positioning and Joint Insufflation Substantially Influence Median and Radial Nerve Locations

The median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have identified the position of these nerves, little is known about how elbow positioning and joint insufflation might influence nerve locations. In a cadaver model, we sought to determine whether (1) the locations of the median and radial nerves change with variation of elbow positioning; and whether (2) flexion and joint insufflation increase the distance of the median and radial nerves to osseous landmarks after correcting for differences in size of the cadaveric specimens. The median and radial nerves were marked with a radiopaque thread in 11 fresh-frozen elbow specimens. Three-dimensional radiographic scans were performed in extension, in 90A degrees flexion, and after joint insufflations in neutral rotation, pronation, and supination. Trochlear and capitellar widths were analyzed. The distances of the median nerve to the medial and anterior edge of the trochlea and to the coronoid were measured. The distances of the radial nerve to the lateral and anterior edge of the capitulum and to the anterior edge of the radial head were measured. We analyzed the mediolateral nerve locations as a percentage function of the trochlear and capitellar widths to control for differences regarding the size of the specimens. The mean distance of the radial nerve to the lateral edge of the capitulum as a percentage function of the capitellar width increased from 68% +/- 17% in extension to 91% +/- 23% in flexion (mean difference = 23%; 95% confidence interval [CI], 5%-41%; p = 0.01). With the numbers available, no such difference was observed regarding the location of the median nerve in relation to the medial border of the trochlea (mean difference = 5%; 95% CI, -13% to 22%; p = 0.309). Flexion and joint insufflation increased the distance of the nerves to osseous landmarks. The mean distance of the median nerve to the coronoid tip was 5.4 +/- 1.3 mm in extension, 9.1 +/- 2.3 mm in flexion (mean difference = 3.7 mm; 95% CI, 2.04-5.36 mm; p < 0.001), and 12.6 +/- 3.6 mm in flexion and insufflation (mean difference = 3.5 mm; 95% CI, 0.81-6.19 mm; p = 0.008). The mean distance of the radial nerve to the anterior edge of the radial head increased from 4.7 +/- 1.8 mm in extension to 7.7 +/- 2.7 mm in flexion (mean difference = 3.0 mm; 95% CI, 0.96-5.04 mm; p = 0.005) and to 11.9 +/- 3.0 mm in flexion with additional joint insufflation (mean difference = 4.2 mm; 95% CI, 1.66-6.74 mm; p = 0.002). The radial nerve shifts medially during flexion from the lateral to the medial border of the inner third of the capitulum. The median nerve is located at the medial quarter of the joint. The distance of the median and radial nerves to osseous landmarks doubles from extension to 90A degrees flexion and triples after joint insufflation. Elbow arthroscopy with anterior capsulectomy should be performed cautiously at the medial aspect of the joint to avoid median nerve lesions. Performing arthroscopic anterior capsulectomy in flexion at the lateral aspect of the joint and in slight extension at the medial edge of the capitulum could enhance safety of this procedure

The circumferential graft technique for treatment of multidirectional elbow instability: a comparative biomechanical evaluation

Background: Ligament reconstruction with a circumferential graft represents an innovative technique for treatment of multidirectional elbow instability. This biomechanical study compared the stability of the intact elbow joint with the circumferential graft technique and the conventional technique. Methods: Seven fresh frozen cadaveric elbows were evaluated for stability against valgus and varus/posterolateral rotatory forces (3 Nm) over the full range of motion. Primary stability was determined for intact specimens, after sectioning of the collateral ligaments, after applying the circumferential graft technique (box-loop), and after conventional collateral ligament reconstruction. Cyclic loading (1000 cycles) was performed to assess joint stability and stiffness of the native ligaments and the tendon grafts. Results: Primary stability of both reconstruction techniques was equal to the native specimens (P = .17.91). Sectioning of the collateral ligaments significantly increased joint instability (P < .001). The reconstruction techniques provided equal stability after 1000 cycles (P = .78). Both were inferior to the intact specimens (P = .02). Cyclic loading caused a significantly lower increase in stiffness of the native ligaments compared with the tendon grafts of either reconstruction technique (P = .001-.008). Significantly better graft stiffness was retained with the circumferential graft technique compared with conventional reconstruction (P = .04). Conclusion: Neither reconstruction technique fully reproduces the biomechanical profile of the native collateral ligaments. The circumferential graft technique seems to resist cyclic loading slightly better than the conventional reconstruction technique, yet both reconstruction techniques provide comparable stability. (C) 2016 Journal of Shoulder and Elbow Surgery Board of Trustees