Relation of the radial nerve to the anterior capsule of the elbow: anatomy with correlation to arthroscopy

Endoscopic anterior capsulectomy for severe elbow contractures

Elbow stiffness secondary to trauma or surgical reconstruction can sometimes result in a severe contracture with restricted joint space, and arthroscopic access to the joint is difficult. Previous surgery and severe stiffness can also alter the position of neurovascular structures and iatrogenic injury is possible with an inside-out arthroscopic approach. To overcome these technical difficulties, an endoscopic approach to the anterior capsule can be performed as an alternative to open approach. The endoscopic approach utilises the sub-brachialis space for an outside-in capsular resection under vision. Identification of standard anatomic landmarks is useful as a guide for safe resection in a central to peripheral direction.

Needle arthroscopy of the elbow through an anterior transbrachial portal

Background

Current innovation in needle arthroscopy is improving the safety of anterior portals around the elbow. This study evaluated the proximity to the radial nerve, median nerve, and brachial artery on cadaveric specimens of an anterior portal used for elbow arthroscopy.

Methods

Ten fresh-frozen adult cadaveric extremities were used. After marking the cutaneous references, the NanoScope cannula was introduced just lateral to the biceps tendon, through the brachialis muscle and the anterior capsule. Elbow arthroscopy was performed. Dissection was then carefully performed on all specimens with the NanoScope cannula in place. The shortest distance from the cannula to the median nerve, radial nerve, and brachial artery was measured with a handheld sliding digital caliper.

Results

The cannula was an average of 12.92 mm away from the radial nerve, 22.27 mm from the median nerve, and 16.8 mm from the brachial artery. Needle arthroscopy performed through this portal allows complete visualization of the anterior compartment of the elbow, as well as direct visualization of the posterolateral compartment.

Conclusion

Needle arthroscopy of the elbow through an anterior transbrachialis portal is safe for the main neurovascular structures. In addition, this technique allows complete visualization of the anterior and posterolateral compartments of the elbow through the humerus-radius-ulna space.

Application of ultrasound in avoiding radial nerve injury during elbow arthroscopy: a retrospective follow-up study

BACKGROUND

A safe and effective technique for anterolateral portal placement in elbow arthroscopy is significant. We compared the outcomes of patients who underwent elbow arthroscopy using different ultrasound-assisted techniques.

METHODS

From May 2016 to June 2021 a retrospective analysis on all patients who underwent elbow arthroscopy in our department was performed. Patients were separated into three groups: non-ultrasound; preoperative ultrasound; and intraoperative ultrasound. The minimum follow-up period was 1 year. Nerve injuries, visual analog scale (VAS), Mayo elbow-performance score (MEPS), Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH), and range of motion (ROM) of the elbow were evaluated for comparison among the three groups pre- and post-operatively.

RESULTS

All 55 patients completed a 1-year follow-up: non-ultrasound (n = 20); preoperative ultrasound (n = 17); and intraoperative ultrasound (n = 18). There were 3 cases (15.0%) of transient radial nerve palsy in the non-ultrasound group. No nerve complications occurred in preoperative ultrasound and intraoperative ultrasound groups. The probability of postoperative radial nerve injury in the three groups was statistically different (P < 0.05). There was no significant difference in the VAS score, MEPS, DASH score, and ROM among the three groups at the follow-up evaluation (P > 0.05).

CONCLUSION

Performing anterolateral portal placement during elbow arthroscopy with ultrasound-assisted techniques successfully avoided radial nerve injury.

Substantiation of safe and effective arthroscopic approaches to the elbow joint in case of enthesopathy of the distal humerus

Background: With the development of arthroscopic surgical techniques, diagnostic and therapeutic possibilities have significantly expanded, but they have not become widely used in everyday clinical practice in the treatment of elbow joint pathology. This is due to the small volume of the joint, the close location of the neurovascular formation and the complexity of manipulation. Elbow arthroscopy is a dynamic procedure with a change in the ratio of neurovascular structures and portals in different elbow positions. The risk of damage to neurovascular formations during arthroscopy of the elbow joint is up to 14%. Purpose: determination of the safest areas promising for the formation of arthroscopic approaches to the elbow joint in the treatment of patients with enthesopathy of the distal humerus.. Methods: To achieve this goal, a complex topographic- anatomical and clinical study was performed on 30 non-fixed anatomical preparations of the upper limb, which included 4 stages, where the topographic and anatomical features of the tendon-muscular and neurovascular structures forming the elbow joint were studied, depending on the angle of flexion of the elbow joint at 3 different levels: level I - 5 cm above the joint space, level II - joint space, level III - the neck of the radius, additionally the above structures were studied using MRI studies in 30 patients. Results: When the elbow joint is flexed to 90, the brachial artery at level I moves away from the bone and is located at a distance from 27,8 (27.7-28,1) mm to 28,6 (28,4-28,7). The radial nerve at the II level from СMEL is located at 16,4 (16,5-18,8) mm. Median nerve from СMEL by 17,5 (16,6-18,1) mm. The brachial artery is 23,7 (20,522,8) mm distant from the СMEL. The anterior bundle of the MCL has: an average proximal width of 6,2 1,4 mm, an average width of the middle part of 6,5 1,5 mm, an average distal width of 9,3 1,4 mm. The average area of attachment on the medial epicondyle of the humerus is 45,5 9,3 mm, it has a rounded shape. The radial collateral ligament has an average length of 20,5 1.9 mm and a bundle width of 5,2 0,8mm. The average area of attachment on the humerus is 13,6 mm. The average area of ECRB on the lateral epicondyle of the humerus was 53,1 3,7mm. The mean area of the FCR on the medial epicondyle was 58,3 6.3mm. The distance from the entrance of the deep branch of the radial nerve to the canalis sapinatorius to the joint space is 28 (25,529,6) mm. Conclusion: The results of this study allow the operating surgeon to decide on the choice and placement of arthroscopic access to the elbow joint, which in turn helps to minimize the risk of damage to neurovascular structures.

Identifying the Safe Zone in Arthroscopic Anterior Elbow Capsulectomy: A Cadaveric Study

The authors assessed the effects of forearm rotation on the proximity of the radial nerve and medial collateral ligament (MCL) to a proximal and a more distal arthroscopic anterior elbow capsulectomy. Arthroscopy was performed on 10 cadaveric specimens. Sutures were passed lateral to medial at the level of the radiocapitellar joint and at the proximal edge of the annular ligament. Dissection measured the distance to the radial nerve from the lateral starting point and to the MCL from the medial exit point in varying degrees of forearm rotation. The extent of brachialis muscle coverage of the radial nerve was documented. The distance from the starting point to the radial nerve increased in pronation at both levels. The medial extent of the capsulectomy remained a safe distance from the MCL. Brachialis muscle covered the radial nerve at both levels. Pronation increases the capsulectomy safe zone, including more distally, before encountering the radial nerve; the MCL is not at risk. [Orthopedics. 2020;43(5):e399-e403.].

Arthroscopic localization of the ulnar nerve behind the medial capsule is unreliable

Purpose

Ulnar nerve injury is the most common neurologic complication of elbow arthroscopy. The purpose of this cadaveric study was to quantify the ability of surgeons to locate the ulnar nerve behind the posteromedial capsule during elbow arthroscopy using sole arthroscopic vision.

Methods

Twenty-one surgeons were asked to pin the ulnar nerve at the medial gutter and the posteromedial compartment using arthroscopic visualization of the medial capsule only. Pinning of the ulnar nerve was performed from extra-articular. Then, the cadaveric specimens were dissected and the shortest distances between the pins and ulnar nerve measured.

Results

Median pin-to-nerve distances at the medial gutter and posteromedial compartment were 0 mm (interquartile range [IQR], 0-3 mm) and 2 mm (IQR, 0-6 mm), respectively. The ulnar nerve was pinned by 11/21 surgeons (52%) at the medial gutter, and 7/21 surgeons (33%) at the posteromedial compartment. Three of 21 surgeons (14%) pinned the ulnar nerve at both the medial gutter and the posteromedial compartment. Surgeon's experience and operation volume did not affect these outcomes (P > .05).

Conclusions

Surgeons' ability to locate the ulnar nerve behind the posteromedial capsule using sole arthroscopic visualization, without external palpation, is poor. We recommend to proceed carefully when performing arthroscopic procedures in the posteromedial elbow, and identify and mobilize the ulnar nerve prior to any posteromedial capsular procedures.

Neurologic complications after surgical management of complex elbow trauma requiring radial head replacement

BACKGROUND

Radial head arthroplasty (RHA) has become a successful procedure for addressing acute unreconstructible radial head fractures that compromise elbow stability in complex elbow trauma. The purpose of this study was to investigate the incidence of and risk factors for the development of neurologic complications after surgical treatment of complex elbow fractures that require an RHA.

METHODS

Sixty-two patients with an unreconstructible radial head fracture and complex elbow instability treated with RHA were included. There were 33 men and 29 women, with a mean age of 54 years (range, 22-87 years). The average follow-up period was 5.2 years (range, 3-16 years). All patients were neurologically intact before surgery. The arthroplasty was implanted through a Kocher approach in 55 cases, whereas a Kaplan approach was used in 7. An uncemented smooth stem arthroplasty (Evolve) was used in 27 patients, and an anatomic ingrowth system (Anatomic Radial Head), in 35. At the time of surgery, 23 patients underwent fixation of a coronoid fracture and 15 underwent plating of the proximal ulna. All patients were clinically examined immediately after surgery and during follow-up to detect any degree of neurologic deficit. Radial and ulnar nerve injuries were classified according to the Hirachi and McGowan classifications, respectively. Functional outcomes were evaluated with the Mayo Elbow Performance Score.

RESULTS

A complete posterior interosseous nerve palsy occurred postoperatively in 2 patients. Hand function had completely recovered in both at 2 months after surgery without sequelae. Nine patients complained of ulnar nerve symptoms (immediately after surgery in 6 and as delayed ulnar neuropathy in 3). Most patients with ulnar nerve deficits had undergone additional surgical procedures to address ulnar fractures. Among patients with ulnar neuropathies, only 3 complained of mild sensory symptoms at the latest follow-up. No significant differences in range of motion and Mayo Elbow Performance Score were found between patients with and without neurologic complications. Associated olecranon or coronoid fixation and a prolonged tourniquet time were identified as risk factors for neurologic complications.

CONCLUSION

This study shows that the incidence of neurologic complications associated with the surgical treatment of complex elbow fractures requiring implantation of a radial head prosthesis may be underestimated in the literature. Inappropriate retraction in the anterior aspect of the radial neck, a prolonged ischemia time, and concomitant coronoid or olecranon fracture fixation represent the main risk factors for the development of this complication. Although the great majority of patients have full recovery of their nerve function, they should be advised on the risk of this stressful complication.

Surgical outcomes for post-traumatic stiffness after elbow fracture: comparison between open and arthroscopic procedures for intra- and extra-articular elbow fractures

HYPOTHESIS

We hypothesized that arthroscopic osteocapsular arthroplasty has a comparable outcome to that of the corresponding open procedure.

METHODS

Patients treated with osteocapsular arthroplasty for post-traumatic stiffness were assigned to open procedure (OPEN) and arthroscopic procedure (ARTHRO) groups. The clinical outcomes were measured based on range of motion (ROM), Mayo Elbow Performance Score (MEPS), and visual analog scale (VAS) score. Based on the initial trauma, the patients were grouped into either intra-articular fracture (I) or extra-articular fracture (E) groups, followed by comparison of the 2 groups.

RESULTS

The overall, ROM, VAS, and MEPS scores showed improvement in both groups. Preoperative VAS scores improved from 6.6 ± 1.4 to 2.2 ± 0.9 following OPEN and from 6.5 ± 1.2 to 2.1 ± 1.0 following ARTHRO. Preoperative flexion improved from 88° ± 14° to 113° ± 17° following OPEN and from 102° ± 15° to 122° ± 8° following ARTHRO. Preoperative extension improved from 36° ± 14° to 17° ± 12° following OPEN and from 30° ± 8° to 15° ± 7.4° following ARTHRO. Preoperative MEPS improved from 48.9 ± 11.5 to 80.0 ± 14.8 following OPEN and from 52.3 ± 12.2 to 80.8 ± 7.9 following ARTHRO. All values for the clinical outcomes were worse in group I than in group E.

CONCLUSIONS

Arthroscopic osteocapsular arthroplasty is comparable to the corresponding open procedure with regard to the use of our indications. The clinical outcomes in the intra-articular fracture group as a previous trauma were worse than those in the extra-articular fracture group.

Classification of the transverse pattern of Mason II radial head fractures and its usefulness in arthroscopic osteosynthesis. Anatomo-surgical study

OBJECTIVE

The management of MasonII fracture pattern assisted by arthroscopy is a valid technique that provides good results. The objective of this study was to draw attention to the usefulness of the location of the fracture in the head of the radius in defined quadrants with respect to the bicipital tuberosity through CT. This would help to plan the optimal forearm position to access each quadrant and foresee the specific difficulties of each one.

MATERIAL AND METHOD

We dissected 4 specimens of cryopreserved cadaver. We divided the radial head into 4 quadrants with regard to the bicipital tuberosity, objectifying the change of position in pronation and maximum supination with respect to the sigmoid cavity and neurovascular structures.

RESULTS

The head of the radio moves with pronosupination, so there are areas of convergence between the different quadrants. Quadrant1 is approached in supination via an anteromedial portal. Quadrant2 is approached in maximum pronation through a lateral portal. Quadrant3 can be approached through lateral portals, with the forearm in neutral position and in pronation. Quadrant4 is accessible with the forearm in a neutral position and in supination through a lateral portal.

CONCLUSIONS

Depending on the location of the fracture in the head of the radius with respect to the bicipital tuberosity, we will need access through a specific arthroscopic portal, with the medial quadrants (anteromedial and posteromedial) being the most technically demanding.

Force measurement metrics for simulated elbow arthroscopy training

Background

Elbow arthroscopy is a difficult surgical technique. Objective metrics can be used to improve safe and effective training in elbow arthroscopy. Force exerted on the elbow tissue during arthroscopy can be a measure of safe tissue manipulation. The purpose of this study was to determine the force magnitude and force direction used by experts during arthroscopic elbow navigation in cadaveric specimens and assess their applicability in elbow arthroscopy training.

Methods

Two cadaveric elbows were mounted on a Force Measurement Table (FMT) that allowed 3-dimensional measurements (x-, y-, and z-plane) of the forces exerted on the elbow. Five experts in elbow arthroscopy performed arthroscopic navigation once in each of two cadaveric elbows, navigating through the posterior, posterolateral and anterior compartment in a standardized fashion with visualization of three to four anatomic landmarks per compartment. The total absolute force (F_abs) and force direction exerted (α and β) on the elbow during arthroscopy were recorded. α being the angle in the horizontal plane and β being the angle in the vertical plane. The 10th–90th percentiles of the data were used to set threshold levels for training.

Results

The median F_abs was 24 N (19 N – 30 N), 27 N (20 N – 33 N) and 29 N (23 N – 32 N) for the posterior, posterolateral and anterior compartment, respectively. The median α was - 29° (- 55° – 5°), - 23° (- 56° – -1°) and 4° (- 22° – -18°) for the posterior, posterolateral and anterior compartment, respectively. The median β was - 71° (- 80° – -65°), - 76° (- 86° – -69°) and - 75° (- 81° – -71°) for the posterior, posterolateral and anterior compartment, respectively.

Conclusion

Expert data on force magnitude and force direction exerted on the elbow during arthroscopic navigation in cadaveric specimens were collected. The proposed maximum allowable force of 30 N (smallest 90th percentile of F_abs) exerted on the elbow tissue, and the 10th–90th percentile range of the force directions (α and β) for each compartment may be used to provide objective feedback during arthroscopic skills training.

Arthroscopic debridement for primary elbow osteoarthritis with and without capsulectomy: a comparative cohort study

BACKGROUND

Arthroscopic elbow debridement for primary osteoarthritis may be performed with or without a joint capsulectomy. The purpose of this comparative cohort study was to compare range of motion (ROM) and early complications between patients with and without anterior capsulectomy.

METHODS

In total, 110 patients with primary osteoarthritis of the elbow who underwent an arthroscopic debridement for primary osteoarthritis were reviewed with a minimum of 3 months postoperative follow-up. The first group consisted of 51 patients who had a concomitant capsulectomy and the second group consisted of 59 patients who either had a capsulotomy or did not have the capsule addressed.

RESULTS

There was significantly greater pre-operative stiffness in the group who had an anterior capsulectomy versus those who did not. A greater improvement in arc of ROM occurred in patients who had a concomitant capsulectomy compared to patients without (24° versus 12°) (p < 0.003); however, there were no significant differences in final ROM between groups. There were no statistically significant differences in the incidence of complications between the groups (16% capsulectomy versus 18% no capsulectomy).

CONCLUSIONS

Elbow arthroscopy and debridement for primary elbow osteoarthritis yields satisfactory motion at short-term follow-up with or without a capsulectomy. The incidence of early complications was low at this tertiary referral centre, with no significant differences between groups.

Avoiding Neurological Complications of Elbow Arthroscopy

Elbow arthroscopy is an increasingly common procedure performed in orthopaedic surgery. However, because of the presence of several major neurovascular structures in close proximity to the operative portals, it can have potentially devastating complications. The largest series of elbow arthroscopies to date described a 2.5% rate of postoperative neurological injury. All of these injuries were transient nerve injuries resolved without intervention. A recent report of major nerve injuries after elbow arthroscopy demonstrated that these injuries are likely under-reported in literature. Because of the surrounding neurovascular structures, familiarity with normal elbow anatomy and portals will decrease the risk of damaging important structures. The purpose of this Technical Note is to review important steps in performing elbow arthroscopy with an emphasis on avoiding neurovascular injury. With a sound understanding of the important bony anatomic landmarks, sensory nerves, and neurovascular structures, elbow arthroscopy can provide both diagnostic and therapeutic intervention with little morbidity.

An Anatomic Evaluation of Arthroscopic Access to the Radial Head

PURPOSE

To determine the area of the radial head accessible for visualization and screw placement from the standard anteromedial and anterolateral portals used in elbow arthroscopy.

METHODS

Five cadaveric elbows were arthroscopically evaluated using standard anteromedial and anterolateral portals. Markers (pins) were placed into the accessible portions of the radial head at maximal pronation and supination. Specimens were then evaluated by computed tomography, and the arc of the radial head accessible from each portal was determined.

RESULTS

A continuous 220.04° ± 37.58° arc of the radial head was accessible from the combination of the anterolateral and anteromedial portals. From the anteromedial portal, the arc obtained measured 147.96° ± 21.81°, and from the anterolateral portal, the arc obtained measured 156.02° ± 33.32°. Using the radial styloid as a marker for 0°, the mean total arc ranged from 92.3° ± 34.06° dorsal to 127.74° ± 23.65° volar relative to the radial styloid.

CONCLUSIONS

Standard anteromedial and anterolateral portals used for elbow arthroscopy allow access to an average 220° area of the radial head.

CLINICAL RELEVANCE

This study defines the area of the radial head that can be contacted using commonly used, safe, and simple portals.

Relationship of the Median and Radial Nerves at the Elbow: Application to Avoiding Injury During Venipuncture or Other Invasive Procedures of the Cubital Fossa

Introduction

The median and radial nerves are two important neural structures found in the cubital fossa. The trajectory and landmarks used to identify their location are important when procedures are done in this area.

Methods and materials

Ten fresh-frozen cadavers were dissected (20 upper limbs) and measurements were taken from the medial epicondyle to the median and radial nerves as well as to the lateral epicondyle of each limb.

Results

The distance between the medial epicondyle and the median nerve was found to be three centimeters with a range of 2.1 to four centimeters and the distance from the medial epicondyle to the radial nerve had a mean distance of 5.5 cm and a range of 3.8 to seven centimeters.

Discussion

Damage to the median or radial nerves can lead to major complications including loss of extension, flexion, and sensation in the forearm and hand. Other studies have tried to identify the course of these nerves in order to prevent their injury during procedures.

Conclusion

After identifying the medial epicondyle, using the results we obtained, physicians may have a better understanding of where the median and radial nerves lie within the cubital fossa when performing procedures in this area. 

Tips to avoid nerve injury in elbow arthroscopy

Elbow arthroscopy is a technical challenging surgical procedure because of close proximity of neurovascular structures and the limited articular working space. With the rising number of elbow arthroscopies being performed nowadays due to an increasing number of surgeons performing this procedure and a broader range of indications, a rise in complications is foreseen. With this editorial we hope to create awareness of possible complications of elbow arthroscopy, particularly nerve injuries, and provide a guideline to avoid complications during elbow arthroscopy.

First 50 Pediatric and Adolescent Elbow Arthroscopies: Analysis of Indications and Complications

BACKGROUND

Elbow arthroscopy is a challenging, yet extremely productive procedure in orthopaedic sports medicine. The severely confined anatomy of the pediatric and adolescent elbow is particularly prone for perioperative complications. This study focuses on the indications and complications of the first 50 elbow arthroscopies in skeletally immature patients done in a specialized pediatric orthopaedic department.

PURPOSE

To review analysis of indications and complications in pediatric and adolescent elbow arthroscopy. We hypothesized that the complication rate in these patients is similar to adults.

METHODS

Data on 50 consecutive elbow arthroscopies were prospectively gathered in a dedicated database and retrospectively analyzed for indications and perioperative complications. All procedures were performed by a surgeon trained in orthopaedic sports medicine.

RESULTS

A total of 26 boys and 24 girls with a mean age of 13.6±3.3 years at the time of surgery and a minimum follow-up of 1 year were included.Fifty-eight percent were treated for osteochondritis dissecans, 24% for arthrofibrosis, 14% for a congenital disorder, and 4% for a posttraumatic problem other than arthrofibrosis. The complication rate was 8%, including 3 cases of transient neuropraxia and 1 superficial wound infection. There were no major complications such as septic arthritis, vascular injury, or permanent nerve damage. All complications resolved fully with conservative treatment, no revision were required.

DISCUSSION

Although osteochondritis dissecans is still the leading reason for such surgery, fractures and posttraumatic conditions are becoming more important. With a rate of 5% to 8% of minor, fully resolving complications such an increase is not a reason for concerns.

LEVEL OF EVIDENCE

Level IV-case series.

Complications of Lateral Epicondylar Release

Reported complication rates are low for lateral epicondylitis management, but the anatomic complexity of the elbow allows for possible catastrophic complication. This review documents complications associated with lateral epicondylar release: 67 studies reporting outcomes of lateral epicondylar release with open, percutaneous, or arthroscopic methods were reviewed and 6 case reports on specific complications associated with the procedure are included. Overall complication rate was 3.3%. For open procedures it was 4.3%, percutaneous procedures 1.9%, and arthroscopic procedures 1.1%. In higher-level studies directly comparing modalities, the complication rates were 1.3%, 0%, and 1.2%, respectively.

The incidence of neurologic complications and associated risk factors in elbow surgery: an analysis of 2759 cases

BACKGROUND

The purpose of this study was to evaluate the incidence of neurologic complications after elbow surgery and to provide perioperative tips and potential pitfalls for neurologic complications and how to cope with them.

METHODS

A single orthopedic surgeon performed 2759 elbow-related surgical procedures between January 2006 and October 2014. The surgical records and the postoperative follow-up of all 2759 patients were retrospectively reviewed to determine the preoperative diagnosis, the type of procedure, and postoperative neurologic complications.

RESULTS

Neurologic complications were very uncommon. Neurologic deficit occurred in 10 of 2759 elbow operations. A neurologic complication occurred 4 distal biceps tendon surgeries (5.3%), 4 elbow arthroscopies (0.4%), 2 ligament reconstructions (0.7%), and 2 total elbow prosthesis (1.4%).

CONCLUSIONS

A thorough understanding of the 3-dimensional anatomy of the elbow and surrounding nerves is needed to avoid neurologic complications. The neurologic complications we encountered in our series are well within the limits of earlier reports and show that elbow surgery is a relatively safe procedure to perform for a wide variety of indications.

Arthroscopic Treatment of Annular Drive Through and Radial Lateral Collateral Ligament Articular-Side Tear of the Elbow

An elongation or partial articular-sided tear of the radial lateral collateral ligament (R-LCL) is a rare injury causing disability and instability of the elbow. In our experience this condition is often associated with a pathologic sign of the annular ligament named the "annular drive through" caused by a redundancy of the ligament. The benefits of performing an arthroscopic procedure for surgical stabilization of the R-LCL include smaller incisions with less soft-tissue dissection, better visualization of the joint, better repair accessibility, and elimination of the annular drive-through sign. The main steps of the operation are as follows: evaluation of annular drive through, inspection of the radial side of the joint, anterior capsulotomy, insertion of a suture anchor through the anterolateral portal, shuttling of the suture anchor through the ligament, and elimination of the annular drive-through sign. By use of this technique, it is possible to repair a lesion of the R-LCL with a suture anchor that ensures an anatomic repair and, at the same time, returns the annular ligament to its physiological tension.

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

BACKGROUND

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.

QUESTIONS/PURPOSES

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.

METHODS

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 90° 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.

RESULTS

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).

CONCLUSIONS

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 90° flexion and triples after joint insufflation.

CLINICAL RELEVANCE

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.

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

BACKGROUND

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.

QUESTIONS/PURPOSES

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.

METHODS

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 90° 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.

RESULTS

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).

CONCLUSIONS

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 90° flexion and triples after joint insufflation.

CLINICAL RELEVANCE

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 course of the median and radial nerve across the elbow: an anatomic study

INTRODUCTION

Nerve transection has been described as complication of arthroscopic elbow arthrolysis. Therefore, the goal of this study was to define bony landmarks for intraoperative orientation regarding the location of the median and radial nerve.

METHODS

In 22 formalin-fixated upper extremities, the radial and median nerves were dissected and marked with respect to their native course. A 3D X-ray scan was performed. The distances of the radial nerve to the radial head (R1), the capitulum (R2), and its lateral border (RC) were measured. The location of the radial nerve in relation to the transversal diameter of the humeral condyle (HC) was calculated. Similarly, the distances of the median nerve to the trochlea (M1), the medial border of the trochlea (M2), and its relation to HC were calculated.

RESULTS

The mean value for R1 was 8 mm (±2.9 mm), for R2 was 11.3 mm (±3.8 mm), and for RC was 10.6 mm (±5.1 mm). RC/HC averaged 24 % (±11 %). M1 averaged 11.7 mm (±5.2 mm), and M2 was 2.4 mm (±4.1 mm). M2/HC averaged 6 % (±9 %).

CONCLUSIONS

The radial nerve is located ventral to the central third of the capitulum. The median nerve lies ventral to the medial quarter of the humeral condyle. When performing arthroscopic arthrolysis, this information should be kept in mind during anterior capsulectomy.