Neurovascular crossing patterns between leash of Henry and deep branch of radial nerve: implications for neurointervention and diagnostic imaging.

OBJECTIVE: To detail the neurovascular crossing patterns between the leash of Henry (LoH) and the deep branch of the radial nerve (DBRN) in supination and pronation of the forearm, using imaging methods with anatomic correlation. MATERIALS AND METHODS: This cross-sectional study was performed ex vivo with HRUS and MRI with anatomic correlation on 6 samples and in vivo with HRUS with Doppler on 55 participants scanned bilaterally. The in vivo participants were enrolled over a 6-month period. The crossing patterns between the LoH and DBRN were assessed ex vivo and in vivo. Additional morphological features of the DBRN, LoH, and fat plane were assessed in vivo only. Biometric features of the participants were recorded. Statistical analyses were performed using Shapiro-Wilk, parametric and non-parametric tests. RESULTS: The most common neurovascular crossing pattern was the ascending branch of the radial recurrent artery (RRAab) crossing below (ex vivo: 83.3%, in vivo: 85.3%) and the muscular branch crossing above (ex vivo: 100%, in vivo: 63.2% %) the DBRN. Both the deep and superficial surfaces of the DBRN exhibited an intimate relationship with the vessels of the LoH. A positive correlation between vessel diameter and anthropometric factors was observed. In addition, the muscular branch exhibited a significantly smaller diameter than the RRAab. CONCLUSION: Our study detailed the relationship between the LoH and the DBRN and highlighted the high incidence of vessel crossing above the DBRN at the level of the muscular branch. Knowledge of neurovascular crossings is crucial for understanding neurovascular entrapment syndromes and planning interventional procedures to reduce vascular complications.

Anconeus Muscle Transfer to Correct or Prevent Wrist Radial Deviation in Radial and Posterior Interosseous Nerve Injuries.

PURPOSE: Wrist radial deviation is a possible complication of tendon transfer for restoration of wrist extension in cases of radial nerve paralysis. In posterior interosseous nerve (PIN) injury, this is because of the imbalance caused by the intact extensor carpi radialis longus and paralysis of the extensor carpi ulnaris (ECU). This deformity may also occur following transfer of the pronator teres (PT) to the extensor carpi radialis brevis (ECRB) for radial nerve palsy. To address wrist radial deviation, we propose transferring the anconeus muscle, extended by the intermuscular septum between the ECU and the flexor carpi ulnaris (FCU), to the ECU tendon. METHODS: Through an incision over the ulna, the intermuscular septum between the ECU and FCU is harvested at the level of the periosteum and left attached to the anconeus proximally. The anconeus muscle is then released from the ulna, and the intramuscular septum extension is sutured to the ECU tendon under maximal tension. Anconeus muscle transfer was performed on two patients to correct chronic wrist radial deviation following PT to ECRB tendon transfer for radial nerve injury, as well as on two patients with PIN paralysis. In four patients, transfer was performed in addition to standard tendon transfers for radial nerve paralysis to prevent radial wrist deviation deformity. RESULTS: Wrist radial deviation was corrected or prevented in all but one patient at an average follow-up of 10 months. Patients with PIN lesions and those who had anconeus transfer concomitantly with radial nerve tendon transfers were capable of active ulnar deviation. No patient experienced elbow extension weakness, pain, or instability. CONCLUSIONS: Anconeus muscle transfer extended by intermuscular septum presents a viable alternative for addressing radial deviation of the wrist in cases of PIN nerve lesions or following PT to ECRB tendon transfer in radial nerve paralysis. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Location of the posterior interosseous nerve in relation to common lateral approaches to the elbow.

PURPOSE: The risk of posterior interosseous nerve (PIN) injury during surgical approaches to the lateral elbow varies depending on the chosen approach, level of dissection, and rotational position of the forearm. Previous studies evaluated the trajectory of the PIN in specific surgical applications to reduce iatrogenic nerve injuries. The goal of this study is to examine the location of the PIN using common lateral approaches with varying forearm rotation. METHODS: The Kaplan, extensor digitorum communis (EDC) split, and Kocher approaches were performed on 18 cadaveric upper extremity specimens. Measurements were recorded with a digital caliper from the radiocapitellar (RC) joint and the lateral epicondyle to the point where the PIN crosses the approach in full supination, neutral, and full pronation with the elbow at 90°. The ratio of the nerve's location in relation to the entire length of the radius was also evaluated to account for different-sized specimens. RESULTS: The PIN was not encountered in the Kocher interval. For Kaplan and EDC split, with the forearm in full supination, the mean distance from the lateral epicondyle to the PIN was 52.0 ± 6.1 mm and 59.1 ± 5.5 mm, respectively, and the mean distance from the RC joint to the PIN was 34.7 ± 5.5 mm and 39.3 ± 4.7 mm, respectively; with the forearm in full pronation, the mean distance from the lateral epicondyle to the PIN was 63.3 ± 9.7 mm and 71.4 ± 8.3 mm, respectively, and the mean distance from the RC joint to the PIN was 44.2 ± 7.7 mm and 51.1 ± 8.7 mm, respectively. CONCLUSIONS: The PIN is closer to the lateral epicondyle and RC joint in the Kaplan than EDC split approach and is not encountered during the Kocher approach. The PIN was not encountered within 26 mm from the RC joint and 39 mm from the lateral epicondyle in any approach and forearm position and is generally safe from iatrogenic injury within these distances.

Deep branch of the radial nerve: effect of pronation/supination on longitudinal nerve alignment.

OBJECTIVE: To evaluate the effect of maximal pronation and supination of the forearm on the alignment and anatomic relationship of the deep branch of the radial nerve (DBRN) at the superior arcade of the supinator muscle (SASM) by using high-resolution ultrasound (HRUS). MATERIALS AND METHODS: In this cross-sectional study, HRUS in the long axis of the DBRN was performed in asymptomatic participants enrolled from March to August 2021. DBRN alignment was evaluated by measuring angles of the nerve in maximal pronation and maximal supination of the forearm independently by two musculoskeletal radiologists. Forearm range of motion and biometric measurements were recorded. Student t, Shapiro-Wilk, Pearson correlation, reliability analyses, and Kruskal-Wallis test were used. RESULTS: The study population included 110 nerves from 55 asymptomatic participants (median age, 37.0 years; age range, 16-63 years; 29 [52.7%] women). There was a statistically significant difference between the DBRN angle in maximal supination and maximal pronation (Reader 1: 95% CI: 5.74, 8.21, p < 0.001, and Reader 2: 95% CI: 5.82, 8.37, p < 0.001). The mean difference between the angles in maximal supination and maximal pronation was approximately 7° for both readers. ICC was very good for intraobserver agreement (Reader1: r ≥ 0.92, p < 0.001; Reader 2: r ≥ 0.93, p < 0.001), as well as for interobserver agreement (phase 1: r ≥ 0.87, p < 0.001; phase 2: r ≥ 0.90, p < 0.001). CONCLUSION: The extremes of the rotational movement of the forearm affect the longitudinal morphology and anatomic relationships of the DBRN, primarily demonstrating the convergence of the nerve towards the SASM in maximal pronation and divergence in maximal supination.

Tendon Transfer for Correction of the Radial Deviation Deformity of the Wrist and Centralization in Posterior Interosseous Nerve Palsy.

There are very few descriptions of tendon transfers designed specifically to address the reconstruction of posterior interosseous nerve palsy (PINP). Unlike a radial nerve palsy (RNP), a patient with a PINP is able to extend their wrist but in radial deviation, because of the preserved innervation of the extensor carpi radialis longus (ECRL). Tendon transfers to restore finger and thumb extension in PINP have been extrapolated from tendon transfers to restore these functions in RNP, specifically using flexor carpi radialis, not flexor carpi ulnaris, so as not to further exacerbate the distinctive radial deviation deformity of the wrist. However, the standard pronator teres to extensor carpi radialis brevis transfer for a RNP fails to address or correct the radial deviation deformity in PINP. We present a simple tendon transfer specifically to address this radial deviation deformity in a PINP, by performing a side-to-side tenorrhaphy of the ECRL tendon to the extensor carpi radialis brevis tendon, followed by transection of the ECRL insertion onto the base of the index finger metacarpal distal to the tenorrhaphy. This technique converts a functioning ECRL from a radially deforming force, transferring its vector of pull onto the base of the middle finger metacarpal and so producing centralization of wrist extension in axial alignment with the forearm.

Safe Drill Trajectory for Anatomic Repair of Distal Biceps Tendon Through a Single Incision: A Cadaveric Study.

PURPOSE: We sought to determine the safest drill trajectory to avoid injury to the posterior interosseous nerve (PIN) when performing a repair of a distal biceps tendon to an anatomic location through an anterior, single-incision approach using cortical button fixation. METHODS: A standard anterior approach was performed in 10 cadaveric specimens to expose the distal biceps attachment. Three drill holes were made in the radial tuberosity from the center of the anatomic footprint for the distal biceps tendon insertion with the forearm fully supinated. Holes were made in 30° distal, transverse, and 30° proximal directions. Each hole was made by angling the trajectory from an anterior to posterior and ulnar to radial direction, leaving adequate bone on the ulnar side to accommodate an 8-mm tunnel for the purpose of docking the biceps tendon into bone. The proximity of each drill trajectory to the PIN was determined by making a second incision on the dorsum of the proximal forearm. A K-wire was passed through each hole, and the distance between the PIN and K-wire was measured for each trajectory. RESULTS: The distally directed drill hole placed the trajectory wire closest to the PIN (mean distance, 5.4 mm), contacting the K-wire in 3 cases. The transverse drill trajectory resulted in contact with the PIN in 1 case (mean distance, 7.6 mm). The proximal drill trajectory appeared safest, with no PIN contact (mean distance, 13.3 mm). CONCLUSIONS: In this cadaveric study, the proximal drill trajectory resulted in the widest clearance from the PIN. CLINICAL RELEVANCE: When performing repair of a distal biceps tendon to the anatomic location on the tuberosity, the drill trajectory from the center of the biceps footprint should be radial and proximal to provide the greatest separation between the drill guide and the PIN.

Avoiding the posterior interosseous nerve during 2-incision distal biceps tendon repair: an anatomic study.

BACKGROUND: The posterior interosseous nerve (PIN) is the most commonly injured motor nerve during distal biceps tendon repair resulting in severe functional deficits. Anatomic studies of distal biceps tendon repairs have evaluated the proximity of the PIN to the anterior radial shaft in supination, but limited studies have evaluated the location of the PIN in relation to the radial tuberosity (RT), and none have examined its relation to the subcutaneous border of the ulna (SBU) with varying forearm rotation. This study evaluates the location of the PIN in relation to the RT and SBU to help guide surgeons in safe placement of the dorsal incision and the safest zones of dissection. METHODS: The PIN was dissected from arcade of Frohse to 2 cm distal to the RT in 18 cadaver specimens. Four lines were drawn perpendicular to the radial shaft at the proximal, middle, and distal aspect of and 1 cm distal to the RT in the lateral view. Measurements were recorded with a digital caliper along these lines to quantify the distance between the SBU and RT to the PIN with the forearm in neutral, supination, and pronation with the elbow at 90° flexion. Measurements were also made along the length of the radius at the volar, middle, and dorsal surfaces at the distal aspect of the RT to assess its proximity to the PIN. RESULTS: Mean distances to the PIN were greater in pronation than supination and neutral. The PIN crossed the volar surface of the distal aspect of the RT -6.9 ± 4.3 mm (-13, -3.0) in supination, -0.4 ± 5.8 mm (-9.9, 2.5) in neutral, and 8.5 ± 9.9 mm (-2.7, 13) in pronation. One centimeter distal to the RT, mean distance to the PIN was 0.54 ± 4.3 mm (-4.5, 8.8) in supination, 8.5 ± 3.1 mm (3.2, 14) in neutral, and 10 ± 2.7 mm (4.9, 16) in pronation. In pronation, mean distances from the SBU to the PIN at points A, B, C, and D were 41.3 ± 4.2, 38.1 ± 4.4, 34.9 ± 4.2, and 30.8 ± 3.9 mm, respectively. CONCLUSION: PIN location is quite variable, and to avoid iatrogenic injury during 2-incision distal biceps tendon repair, we recommend placement of the dorsal incision no more than 25 mm anterior to the SBU and carrying out deep dissection proximally first to identify the RT before continuing the dissection distally to expose the tendon footprint. The PIN was at risk of injury along the volar surface at the distal aspect of the RT in 50% with neutral rotation and 17% with full pronation.

Evaluation of lateral epicondylopathy, posterior interosseous nerve compression, and plica syndrome as co-existing causes of chronic tennis elbow.

PURPOSE: A great number of patients that suffer from lateral epicondylitis, commonly called tennis elbow (TE), are not successfully treated, meaning, not getting adequate therapeutic effects and the main origin of the pain not being handled appropriately. The hypothesis of the present study is that the inefficiency of the treatment of the chronic TE may often be due to underdiagnosis of posterior interosseous nerve (PIN) entrapment or and plica syndrome, as the authors believe that those pathologies can often occur simultaneously. METHODS: A prospective cross sectional study was conducted. A total of 31 patients met the required criteria. RESULTS: Thirteen (40.7%) of the patients had more than one source of the lateral elbow pain. Five patients (15.6%) had all three examined pathologies. Six patients (18.8%) had TE and PIN syndrome. Two patients (6.3%) had TE and plica syndrome. CONCLUSION: The present study demonstrated concomitant potential sources of lateral elbow pain in patients diagnosed with chronic TE. Our analysis shows how important it is to systematically diagnose patients that present with lateral elbow pain. The clinical characteristics of the three most common causes of chronic lateral elbow pain, meaning, TE, PIN compression, and plicae syndrome were also analyzed. Having adequate knowledge about the clinical aspects of these pathologies can help with a more effective differentiation of the etiology of chronic lateral elbow pain, and with that, a more efficient and cost-effective treatment plan.

Patient with recurrent neuralgic amyotrophy; right brachial plexitis and left posterior interosseous neuropathy.

Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome or idiopathic brachial plexopathy, is a multifocal inflammatory neuropathy that usually affects the upper limbs. The classic picture is a patient with acute onset of asymmetric upper extremity symptoms, excruciating pain, rapid onset of multifocal paresis often involving winged scapula, and a monophasic course of the disease. 
We present an unusual case of recurrent NA characterized first by right brachial plexitis and then isolated left posterior interosseous nerve palsy. 

Optimal placement for needle electromyography of the supinator muscle: Cadaveric studies.

INTRODUCTION/AIMS: The existing methods for needle electromyography are confusing as to which is the safest and most effective. Our aim was to identify the optimal and safest needle electromyographic insertion site in the supinator muscle. METHODS: We performed a two-step cadaveric dissection of the supinator muscle and related neurovascular structures. The study was performed using 18 upper limbs of 9 fresh adult cadavers (step 1) and 14 upper limbs of 7 fresh adult cadavers (step 2). In step 1, an imaginary line connecting the radial head (RH) and midpoint of the dorsal wrist (RW line) was drawn, and the distance from the RH to the point where the RW line and posterior interosseous nerve (PIN) intersect (L_CROSS) was measured on the RW line. In step 2, the needle was inserted 30 mm distal to the RH according to the results of step 1. After injection with India ink, dissection was performed to measure the distance between the needle insertion site and PIN (L_CROSS_Inj) on the RW line. RESULTS: The median L_CROSS was 51.4 (35.5-65.6) mm. Needle insertion spared the PIN in all cases during step 2, and the needle was inserted into the supinator muscle in all cases. The median L_CROSS_Inj was 27.4 (13.2-39.8) mm. DISCUSSION: A safe and accurate needle insertion site for the supinator muscle is approximately 30 to 40 mm distal to the RH along the RW line.

Finger drop sign as a new variant of acute motor axonal neuropathy.

We propose the finger drop sign as a new clinical variant of acute motor axonal neuropathy (AMAN) defined by immunological and radiological evidence. We identified eight consecutive patients who had AMAN. All of them developed prominent involvement of the finger extensors. We performed magnetic resonance imaging (MRI) of the extremity muscles and serological assays for antiganglioside antibodies and Campylobacter jejuni. Patients with AMAN showed characteristic and a markedly sustained weakness of the finger extensors with a distinctive pattern of the finger drop sign. Limb MRI revealed unevenly distributed abnormal signals in the muscles mainly innervated by the posterior interosseous nerve. All tested patients showed positivity for immunoglobulin G antibody against ganglioside complex of GM1 and phosphatidic acid. A pathophysiological understanding of this unique syndrome can provide further insight into antiganglioside-antibody-mediated axonal injury in Guillain-Barré syndrome.

The arcade of Frohse: a systematic review and meta-analysis.

PURPOSE: The structure of the proximal margin of the superficial layer of the supinator muscle is of high interest to many researches. Its tendinous appearance, called the arcade of Frohse, may be clinically important because of its close relationship to the deep branch of the radial nerve passing beneath it and is considered to be the cause of several syndromes. Given the importance of this structure, we aimed to provide a comprehensive and evidence-based review with meta-analytic techniques. MATERIALS AND METHODS: The meta-analysis was performed in adherence to the PRISMA guidelines. Three medical databases were searched in order to identify all potentially eligible articles. Included studies were assessed for quality and the extracted morphological and morphometric data from the relevant articles was analyzed with the use of random effects meta-analysis. RESULTS: A total of 20 studies were included into this meta-analysis. The pooled prevalence of the arcade of Frohse was calculated to be 66% within the adult population and 0% in the fetuses. Other variations regarding the arcade of Frohse were identified as very rare. Analysis of the morphometric parameters revealed the average proportions to be 23.22 mm for the length, 11.05 mm for the width and the mean thickness is 0.67 mm. CONCLUSIONS: The arcade of Frohse is a commonly found structure in adults and thoughtful knowledge of its texture and morphology is especially useful in neurology, neurosurgery, orthopedics, trauma surgery and hand surgery, because it is considered to be the most common source of compression for the deep branch of the radial nerve.

The anconeus muscle revisited: double innervation pattern and its clinical implications.

PURPOSE: The aim of the present study is to describe in detail the morphology and innervation pattern of the anconeus muscle, bearing in mind clinical implications such as iatrogenic injuries during surgical elbow approaches. METHODS: A cadaveric study was performed; 56 elbows from 28 formalin-fixed cadavers belonging to the Anatomy Department of Universidad Complutense of Madrid were dissected. The triceps-anconeus nerve was located and dissected. A second innervation to the anconeus muscle from a branch of the posterior interosseous nerve (PIN) was occasionally detected. Taking the lateral epicondyle as a landmark, the entry points of both nerves in the muscle were referenced, the triceps-anconeus nerve was referenced at 0°, 30°, 45°, 70° and 90° of elbow flexion, and the PIN branch at 0°. RESULTS: Anconeus muscle was present in all specimens. The triceps-anconeus nerve was present in all of the dissected elbows. A branch from PIN to the anconeus muscle was present in 38 of the 54 elbows (70.4%). There were statistically significant differences in all measurements regarding the specimens' gender, being higher for men. CONCLUSIONS: There is evidence of a high frequency of a double innervation pattern for the anconeus muscle: the main branch of triceps-anconeus muscle depending on the radial nerve, which is liable to being damaged during posterior elbow approaches, and a secondary branch depending on the PIN. There are very few references to this finding in Anatomical literature and none with such a large sample size.

Bilateral Plexiform Neurofibromas of the Posterior Interosseous Nerve Mimicking Dorsal Wrist Ganglions.

A 33-year-old woman presented with bilateral dorsal wrist masses associated with pain and limited range of motion. On initial presentation, the masses were believed to be ganglion cysts and the patient opted for observation. Three years later, she was found to have a chest wall mass diagnosed by biopsy to be a neurofibroma. When she later returned to seek treatment for her wrist masses, magnetic resonance imaging demonstrated posterior interosseous nerve (PIN) neurofibromas. Dorsal wrist masses situated over the scapholunate interval are commonly attributed to ganglion cysts. Neurofibromas of the PIN, although rare, should be considered in the differential diagnosis when a mass elicits pain with percussion, fails to transilluminate, fails aspiration, or if the patient has a history of neurofibromas elsewhere in the body.

Pathological Findings of Hourglass-Like Constriction in Spontaneous Posterior Interosseous Nerve Palsy.

We report the pathological findings of hourglass-like fascicular constriction (HLFC) under optical and electron microscopy. A 24-year-old man with spontaneous posterior interosseous nerve palsy was treated by interfascicular neurolysis at 29 weeks after onset. One fascicle in the radial nerve presented severe HLFC with torsion at 5 cm proximal to the elbow. Functional recovery was achieved by resection of the enlarged fascicle including HLFC and sural nerve grafting. Proximal to the HLFC, the endoneurium was filled with clusters of regenerating nerve fibers. At the level of the HLFC, a complete loss of myelinated nerve fibers and vascular occlusion of endo- and perineurial vessels were found. Few regenerating nerve fibers were observed. Distal to the HLFC, severe endoneurial edema, a complete loss of myelinated and unmyelinated nerve fibers, and bands of Büngner were noted. These electron microscopic findings demonstrated a detailed pathology of the nerve around the HLFC.

Transfer of the Distal Anterior Interosseous Nerve for Thumb Motion Reconstruction in Radial Nerve Paralysis.

PURPOSE: With nerve or tendon surgery, the results of thumb reconstruction to treat radial nerve paralysis are suboptimal. The goals of this study were to describe the anatomy of the deep branch of the posterior interosseous nerve (PIN) to the thumb extensor muscles (DBPIN), and to report the clinical results of transferring the distal anterior interosseous nerve (DAIN) to the DBPIN. METHODS: The PIN was dissected in 12 fresh upper limbs. Myelinated nerve fibers in the DBPIN and DAIN were counted. Five patients with radial nerve paralysis underwent transfer of the motor branch to the flexor carpi radialis to the PIN and a motor branch of the pronator teres to the extensor carpi radialis brevis. In addition, these patients had selective reconstruction of thumb motion by transferring the DAIN to the DBPIN, through either a combined volar and dorsal approach (n = 2) or a single dorsal approach (n = 3) with division of the interosseous membrane. RESULTS: At the origin of the abductor pollicis longus, the DBPIN divided into a lateral branch that innervated the abductor pollicis longus and extensor pollicis brevis, and a medial branch that innervated the extensor pollicis longus and extensor index proprius. The number of myelinated nerve fibers in the DAIN corresponded to 65% of that of the DBPIN. In each of the 5 patients, full thumb motion at the trapeziometacarpal joint was restored with no, or minimal, extension lag at the metacarpophalangeal (MCP) joint. CONCLUSIONS: The anatomy of the DBPIN is predictable. Transferring the DAIN to the DBPIN is feasible through a single dorsal approach, allowing full recovery of thumb motion. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

An Anatomical Study to the Branching Pattern of the Posterior Interosseous Nerve on the Dorsal Side of the Hand.

Partial denervation of the wrist can benefit patients with chronic wrist pain. A complication of partial denervation is loss of proprioception and hypesthesia on the dorsal side of the hand. Our aim is to evaluate whether the sensory branches of the posterior interosseous nerve could contribute to the loss of proprioception and sensation. The branching pattern of the posterior interosseous nerve was studied in 20 cadaveric hands. The terminal branches of the posterior interosseous nerve reached the metacarpophalangeal joints in three specimens (15%), the midshaft of the metacarpals in three specimens (15%), carpometacarpal joints in 11 specimens (55%), and the scapholunate joint in three specimens (15%). The finding that terminal branches of the posterior interosseous nerve can reach the metacarpals and the metacarpophalangeal joints indicates that the posterior nerve may contribute to the proprioception and sensation of the dorsal side of the hand. Clin. Anat., 33:678-682, 2020. © 2019 Wiley Periodicals, Inc.

Evaluation of the supinator muscle and deep branch of the radial nerve: impact on nerve compression.

PURPOSE: The aim of this study was to investigate the superficial head of supinator muscle (SM) and deep branch of the radial nerve (DBRN) course in SM to see whether the texture characteristics of the superficial head of SM might have a potential compressive effect on the nerve. MATERIALS AND METHODS: Elbow and proximal forearm region of 20 preserved cadavers (n 40, 12 M, 8 F) were dissected in order to measure total and part of DBRN lengths between some reference points. The texture characteristics of both the proximal (where DBRN enters SM) and distal arcade (where DBRN exits SM) of the superficial head of SM were evaluated based on its structure's being muscular, musculotendinous, tendinous, or membranous. RESULTS: The total length of DBRN between sexes without taking side (L/R) into consideration (P = 0.030) and left radiocapitellar joint (RCJ)-arcade of Frohse (AF) length between sexes (P = 0.050) were statistically significant. There was a gradual increase in caliber getting more flattened in every consecutive level which was statistically significant when every two consecutive levels were compared. When compared according to the texture type, there were also significant differences. CONCLUSIONS: Flattening of DBRN in the supinator canal suggests a chronic compression on the nerve. Differences in the texture of the superficial head of the supinator might facilitate this compression. An understanding of the anatomy and nerve topography is of utmost importance in the accurate diagnosis and effective management of peripheral nerve compression.

The course of posterior interosseous nerve in the wrist capsule. An anatomical study using the modified Sihler's staining.

The aim of the study was to assess the course of posterior interosseous nerve in the wrist capsule in the transparent method of nerve staining. MATERIAL AND METHODS: Thirty dorsal wrist capsules were collected bilaterally from 15 donors (thirty capsules) within 12 hours of death. By the dorsal incision the capsules were collected in the same manner. The specimens were stained according to the protocol of modified Sihler's staining technique. The preserved capsules were analysed under 8-16× magnification of optical microscope for the presence of major posterior interosseous nerve trunks, their major and minor branches, and nerve connections. RESULTS: Three main types of nerve course were identified within the joint capsule. Type I - the most common, with the presence of a single trunk with the excursion of the first main branch on the radial side, two main branches on the ulnar side, the presence of the prevailing number of small branches on the radial side and the presence of 3-4 branches extending beyond the level of the carpo-metacarpal joints. Type II with the presence of two main nerve trunks, running almost in parallel with the first main branch on the radial side, two main branches on the ulnar side with presence of a predominant number of small branches on the radial side and the presence of 3-4 branches running beyond the level of carpo-metacarpal joints. Type III (least often) with the presence of crossed main nerve trunks. CONCLUSION: The modified Sihler's staining technique allows for transparent visibility of the nerves innervation the dorsal wrist capsule. However does not allow accurate assessment as histological examination, especially in evaluation of nerve endings, but it gives a significantly larger area of nerve observation.

Intramedullary Cortical Button Repair for Distal Biceps Tendon Rupture: A Single-Center Experience.

PURPOSE: The aim of this retrospective study was to evaluate the clinical outcome and complication rate of intramedullary cortical button repair for distal biceps tendon rupture (partial and complete tears). METHODS: Between 2010 and 2014, a total of 28 patients with an acute distal biceps tendon rupture underwent intramedullary cortical button repair. Twenty-four patients (mean age, 49 years) with a mean follow-up of 28 months were included in the study. Twenty patients were examined clinically and by maximum isometric strength testing in flexion (at 90°) and supination of both arms. Twenty-four patients completed functional scores including the Mayo Elbow Performance Score (MEPS), the Andrews-Carson-Score (ACS) and the shortened Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire. Furthermore, follow-up radiographs of 24 patients were analyzed. RESULTS: Compared with the contralateral elbow, the active range of motion (ROM) was the same. The mean strength for flexion was 100.8% ± 14% and for supination 93.1% ± 22% compared with the uninjured side. The mean MEPS for all patients was 95.6 ± 8.2, the mean ACS 194.2 ± 9.4 and the QuickDASH 3.8 ± 7.6. Heterotopic ossification (HO) was seen on radiographs in 46% of patients, but was symptomatic in only 1 patient. One patient suffered a tendon rerupture, and 1 asymptomatic button migration was seen in the follow-up. CONCLUSIONS: Intramedullary cortical button repair provides good results with respect to strength, ROM, and functional outcomes. Because the posterior cortex is not violated, the risk of iatrogenic posterior interosseous nerve injury is minimized. However, the patient should be warned of a high prevalence of postoperative HO. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.