A Review of the Typical Course of the Musculocutaneous Nerve into the Coracobrachialis Muscle: Its Variability and Possible Clinical Implications.

OBJECTIVE: This literature review highlights the prevalence of the typical course of the musculocutaneous nerve (MCN) through the coracobrachialis muscle (CB), and evaluates the distance from the entrance point of the MCN to the CB, taking the coracoid process (CP) as a landmark. METHODS: PubMed (MEDLINE), Scopus, and CINAHL online databases were searched in December 2022 for studies reporting the prevalence of the MCN's typical course and the distance between the CP and the MCN entrance point to the CB. RESULTS: Twenty-eight studies were included (including 2846 subjects) investigating the MCN's typical course, and eliciting a prevalence of 93.4%. The mean distance of the CP to the entrance point of the MCN's main trunk into the CB was 5.6±2cm (median 6.1cm, in 550 subjects). In 76.12% of cases the MCN's accessory branches entered the CB proximally to the MCN's main trunk. The mean distance from the CP to the entrance point of the MCN's proximal branches to the CB was 3.8±1.2cm (median 3.7cm, in 140 subjects). CONLCUSION: In the vast majority of cases, the MCN had a typical course through the CB. In cases of altered anatomy, the MCN was either absent or passed medially to the CB (without piercing it). The average entrance point of the MCN into the CB from the CP is 5.6 cm. Proximal motor branches of the MCN to the CB are common and usually arise at a mean distance of 3.8cm from the inferior border of the tip of the CP. Surgeons should be aware of both the MCN's typical and its atypical course and these distances to avoid possible complications when operating in the area.

Coracobrachialis muscle morphology and coexisted neural variants: a cadaveric case series.

PURPOSE: The current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as associated adjacent neuromuscular variants. MATERIALS AND METHODS: Twenty-seven (24 paired and 3 unpaired) cadaveric arms were dissected to identify the coracobrachialis possible variants with emphasis on the musculocutaneous nerve course and coexisted neural variants. RESULTS: Four morphological types of the coracobrachialis were identified: a two-headed muscle in 62.96% (17/27 arms), a three-headed in 22.2% (6/27), a one-headed in 11.1% (3/27), and a four-headed in 3.7% (1 arm). A coracobrachialis variant morphology was identified in 37.04% (10/27). A three-headed biceps brachii muscle coexisted in 23.53% (4/17). Two different courses of the musculocutaneous nerve were recorded: 1. a course between coracobrachialis superficial and deep heads (in cases of two or more heads) (100%, 24/24), and 2. a medial course in case of one-headed coracobrachialis (100%, 3/3). Three neural interconnections were found: 1. the lateral cord of the brachial plexus with the medial root of the median nerve in 18.52%, 2. the musculocutaneous with the median nerve in 7.41% and 3. the radial with the ulnar nerve in 3.71%. Duplication of the lateral root of the median nerve was identified in 11.1%. CONCLUSIONS: The knowledge of the morphology of the muscles of the anterior arm compartment, especially the coracobrachialis variant morphology and the related musculocutaneous nerve variable course, is of paramount importance for surgeons. Careful dissection and knowledge of relatively common variants play a significant role in reducing iatrogenic injury.

Patients with femoral neck fractures treated by bipolar hemiarthroplasty have superior to unipolar hip function and lower erosion rates and pain: a systematic review and meta-analysis of randomized controlled studies.

PURPOSE: We assessed acetabular erosion, hip function, quality of life (QoL), pain, deep infection, mortality, re-operation and dislocation rates in patients with displaced femoral neck fractures (dFNFs) treated with unipolar versus bipolar hemiarthroplasty at different postoperative time points. METHODS: Relevant Randomized Controlled Trials (RCTs) were identified, following comprehensive literature research in Medline, Cochrane Central and Scopus databases, from conception until August 31th, 2021 and analyzed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. RESULTS: Database research retrieved 120 studies; sixteen met eligibility criteria, providing 1813 (1814 hips) evaluable patients. Acetabular erosion was significantly higher for unipolar group at 6 and 12 months (p = 0.02 and p = 0.01 respectively). Patients in the bipolar group presented significantly better hip function at 12 and 24 months (p = 0.02 and p = 0.04 respectively). Postoperative pain was significantly less in the bipolar group at 12, 24 and 48 months (p = 0.01). No statistically significant differences were found regarding the postoperative rates of deep infection, mortality, re-operation and dislocation. CONCLUSION: This study showed that patients with dFNFs treated with bipolar hemiarthroplasty have lower acetabular erosion rates at 6 and 12 months postoperatively, better hip function at 12 and 24 months, better QoL and less pain, when compared with unipolar. No statistically significant difference could be established regarding deep infection, mortality, re-operation and dislocation rates.

Comparison between all-suture and biocomposite anchors in the arthroscopic treatment of traumatic anterior shoulder instability: A retrospective cohort study.

PURPOSE: Suture anchors have revolutionized arthroscopic surgery, enabling direct soft tissue-to-bone repair. There are many types of anchors still used in arthroscopic shoulder operations. We sought to compare the clinical outcome of all-suture and biocomposite anchors when used in arthroscopic Bankart repair for patients suffering from anterior shoulder instability. METHODS: A single-center retrospective cohort study of 30 patients (mean age: 26.6 years, SD: 8.8 years, male/female ratio: 5/1, mean follow up: 28 months, SD: 23.8, range: 12-92) with anterior shoulder instability was conducted. Patients were divided into 2 groups based upon the type of suture anchors used for the Bankart repair: group A (14 patients) used only all-suture anchors and group B (16 patients) used only biocomposite anchors. Outcomes reported were postoperative dislocations, positive shoulder apprehension test, self-reported sense of shoulder instability, return to activities of daily living, return to sports, patient satisfaction and complications. Patient reported outcome measures (PROMs) used were the Rowe Score for Instability, Constant Shoulder Score, Walch Duplay Score, The American Shoulder and Elbow Surgeons (ASES) Shoulder Score, Oxford Shoulder Instability Score and external rotation at 90° of arm abduction, external rotation at 0° of arm abduction, forward flexion, abduction, adduction and internal rotation. RESULTS: Rates of postoperative shoulder dislocation demonstrated no significant difference between the 2 groups (p > .05). Four postoperative dislocations happened, two in each group (14.3% and 12.5% for all suture only and biocomposite only groups, respectively), with three of them being traumatic. In addition, no significant differences were observed amongst groups regarding shoulder apprehension test (group A: 85.7% vs. group B: 93.8%), sense of shoulder instability (7.1% vs. 6.3%), return to activities of daily living (group A: 85.7% vs. group B: 93.8%), return to sports (group A: 85.7% vs. group B: 87.5%), patient satisfaction (moderate level: group A 21.4% vs. group B 12.5%), and PROMs. CONCLUSION: The short-term failure rate and clinical/functional outcomes of arthroscopic Bankart repair using all-suture anchors is similar to the use of biocompatible anchors. LEVEL OF EVIDENCE: Level III, retrospective cohort study.