Neurologic Complications of Shoulder Surgery:

The Incidence of Carpal Tunnel Syndrome Diagnosis Increases after Arthroscopic Shoulder Surgery

Purpose

Arthroscopic shoulder surgery has been identified as a potential risk factor for carpal tunnel syndrome (CTS). The purposes of this study were as follows: to (1) examine the percentage of patients who underwent arthroscopic shoulder procedures and later developed ipsilateral CTS within 1 year of the procedure, (2) determine the percentage of those patients with CTS who subsequently underwent an injection or release, and (3) examine comorbidities associated with developing CTS after surgery.

Methods

Patients who underwent arthroscopic rotator cuff repair (RCR), labral repair, or biceps tenodesis were retrospectively identified in a national database. Within 1 year, we compared the rates of ipsilateral CTS diagnoses versus the contralateral side. The rates of comorbidities between those who did and did not develop CTS were also compared.

Results

Within 1 year, arthroscopic RCR patients (1.47% vs 1.00%; odds ratio [OR], 1.48; P < .001) and arthroscopic labral repair patients (0.76% vs 0.52%; OR, 1.47; P < .001) had a significantly higher rate of ipsilateral carpal tunnel diagnosis versus contralateral side diagnosis. Arthroscopic RCR patients were also significantly more likely to have ipsilateral carpal tunnel injection (0.16% vs 0.11%; OR, 1.45; P < .001) and release (0.46% vs 0.37%; OR, 1.24; P < .001). Patients who had an ipsilateral carpal tunnel diagnosis following arthroscopic RCR and labral repair were both significantly older (both P < .001), a higher percentage of women (both P<.001), and more likely to have had a preoperative nerve block (both P < .05). Both cohorts had significantly higher mean Elixhauser comorbidity Index (P < .001) and more comorbidities.

Conclusions

This study demonstrated a significantly higher incidence of operative side CTS within 1 year following arthroscopic RCR and labral repairs. Arthroscopic RCR was also demonstrated to result in significantly higher rates of injections and carpal tunnel release. The cohort that developed ipsilateral CTS was older, had higher percentage of women, and had more comorbidities.

Type of study/level of evidence

Prognostic III.

Low rates of serious complications after open Latarjet procedure at short-term follow-up

PURPOSE

To report on intraoperative and short-term postoperative adverse events after open Latarjet procedure in patients with recurrent anterior shoulder instability. These complications were classified into different grades of severity based on the treatment required and the learning curve of the procedure.

METHODS

Ninety-six patients (102 shoulders) underwent open Latarjet procedure for recurrent post-traumatic anterior glenohumeral instability between 2012 and 2020. The minimum duration of patients' follow-up was 6 months. Adverse events were classified into 3 classes based on the severity and subsequent treatment. The complications in the first 50% of all cases were compared with the latter 50% to evaluate the role of learning curve on the complication rates.

RESULTS

The mean follow-up was 7.2 ± 2.8 months. The patients' mean age was 26.7 ± 8.9 years and consisted of 83 (86.4%) male and 13 (13.6%) female patients. The total adverse events rate was 18.6%. Adverse events requiring no additional treatment (class 1) occurred in 6 cases (5.8%) including fibrous union (3.9%) and asymptomatic resorption of the graft (1.9%). Adverse events requiring additional or extended nonoperative management (class 2) occurred in 8 cases (7.8%), including coracoid fracture (2.9%), musculocutaneous nerve palsy (1.9%), axillary nerve palsy (0.9%), suprascapular nerve palsy (0.9%), and stiffness (0.9%). All the nerve palsies recovered without long-term sequelae. Adverse events requiring secondary operative procedures (class 3) occurred in 5 cases (4.9%), including symptomatic hardware (1.9%), medial healing of the graft (0.9%), screw loosening (0.9%), and deep infection (0.9%). The rate of adverse events in revision cases was higher than primary cases in 11.7% and 6.8%, respectively (P = .119). The complication rate was significantly higher in the first half of the surgeons' practice (14.7%) than in the second half (3.9%) (P ≤ .05).

CONCLUSIONS

The overall complication rate reported in this open Latarjet series is 18.6%; however, the rate of class 3 adverse events that required additional surgery or long-term medical treatment was only 4.9%. Revision cases had a higher rate of complications than primary cases, and the learning curve has had a significant impact on the rate of adverse events.

Incidence, Risk Factors, Prevention, and Management of Peripheral Nerve Injuries Following Shoulder Arthroplasty

In this article, the authors review the incidence and causes of iatrogenic peripheral nerve injuries following shoulder arthroplasty and provide preventative measures to decrease nerve injury rate and management options. They describe common direct and indirect causes of injury such as laceration and retractor use versus arm positioning and lengthening, respectively. Preventative measures include an understanding of anatomy and high-risk locations in the shoulder, minimizing extreme ranges of arm motion and utilization of intraoperative nerve monitoring. Lastly, the authors review diagnosis and management of neurologic symptoms including how and when to use electrodiagnostic studies, nerve grafts, transfers, or muscle/tendon transfers.

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.

Prevention and Treatment of Nerve Injuries in Shoulder Arthroplasty

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Nerve injuries during shoulder arthroplasty have traditionally been considered rare events, but recent electrodiagnostic studies have shown that intraoperative nerve trauma is relatively common.

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The brachial plexus and axillary and suprascapular nerves are the most commonly injured neurologic structures, with the radial and musculocutaneous nerves being less common sites of injury.

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Specific measures taken during the surgical approach, component implantation, and revision surgery may help to prevent direct nerve injury. Intraoperative positioning maneuvers and arm lengthening warrant consideration to minimize indirect injuries.

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Suspected nerve injuries should be investigated with electromyography preferably at 6 weeks and no later than 3 months postoperatively, allowing for primary reconstruction within 3 to 6 months of injury when indicated. Primary reconstructive options include neurolysis, direct nerve repair, nerve grafting, and nerve transfers.

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Secondary reconstruction is preferred for injuries presenting >12 months after surgery. Secondary reconstructive options with favorable outcomes include tendon transfers and free functioning muscle transfers.

90-Day Complication Rate After the Latarjet Procedure in a High-Volume Center

BACKGROUND

The Latarjet procedure is indicated for patients with recurrent anterior shoulder instability, previous failed soft tissue stabilization, glenoid bone loss, or high-risk factors for recurrence, although there is still a concern with the surgical complication rates associated with the Latarjet procedure.

PURPOSE

To evaluate the 90-day complication rate after the open Latarjet procedure in a high-volume center.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective review was performed of patients who underwent an open Latarjet procedure at our institution over a 5-year period between January 2015 and December 2019. The complications, readmissions, and reoperations within 90 days were evaluated.

RESULTS

A total of 441 patients with a mean age of 23.0 ± 5.7 years was included; 97.5% of the patients were male. There were 2 intraoperative complications (0.5%): 1 coracoid fracture and 1 anaphylactic reaction to vancomycin. Overall, there were 19 postoperative complications (4.3%) in 18 patients, with 4 (0.9%) readmissions for revision surgery. Hematomas were the most common complication, occurring in 12 patients (2.7%), with 9 (2.0%) requiring a return to the operating theater during their stay for an evacuation. In those who required a readmission for a reoperation, 1 was for a hematoma requiring a washout, 2 were for irrigation and debridement of a surgical site infection, and the third was for a biceps tenodesis in a patient with severe bicipital pain. No patients had recurrence or any postoperative graft complications; additionally, there were no neurovascular complications.

CONCLUSION

We found that in a high-volume center, the open Latarjet procedure has a low 90-day complication rate with a low revision rate. Hematomas were the most common complication experienced by patients who underwent the Latarjet procedure, while there was no recurrent instability or neurological or hardware complications reported among the 441 patients included in this study.

How close is the axillary nerve to the inferior glenoid? A magnetic resonance study of normal and arthritic shoulders

INTRODUCTION

Axillary nerve injury is a major complication of shoulder surgery during glenoid exposure. The aim of this study was to measure the mean distance between the inferior glenoid and the axillary nerve in healthy shoulders and then to compare this distance between osteoarthritic and rotator cuff deficient glenohumeral joints.

METHODS

The magnetic resonance images of 50 patients with normal glenohumeral joints were reviewed. The infra-glenoid tubercle was determined as a fixed point and the distance to the axillary nerve was measured. Two separate assessors measured on the same sagittal sections. With a study power of 80%, the sample needed in each comparison group was 28 patients. Measurements were then performed on scans in patients with osteoarthritis and cuff tear arthropathy. The mean distance was compared between groups.

RESULTS

The mean distance between the infra-glenoid tubercle and axillary nerve was 12mm (standard deviation, SD, 5.6mm) in normal shoulders, 10.6mm (SD 5.4mm) in shoulders with osteoarthritis and 9.7mm (SD 3.7mm) in those with cuff tear arthropathy. For this sample size of 50 patients with a confidence interval of 95%, the mean range is 12mm (95% CI 10.4-13.6). A comparison between normal shoulder and osteoarthritis showed a p-value of 0.3, and between normal and cuff tear arthropathy a p-value of 0.06. This was not statistically significant.

CONCLUSIONS

The axillary nerve lies on average 12mm from the infra-glenoid tubercle. The presence of inferior osteophytes in glenohumeral osteoarthritis and the proximal migration of humeral head in cuff tear arthropathy does not seem to alter the course of the nerve significantly in relation to the inferior glenoid tubercle.

Sensory innervation of the subacromial bursa by the distal suprascapular nerve: a new description of its anatomic distribution

BACKGROUND

Sensory innervation to the shoulder provided by the distal suprascapular nerve (dSSN) remains the subject of debate. The purpose of this study was to establish consensus with respect to the anatomic features of the sensory branches of the dSSN. The relevant hypothesis was that the dSSN would give off 3 sensory branches providing innervation to the posterior glenohumeral (PGH) capsule, the subacromial bursa, in addition to the coracoclavicular and acromioclavicular ligaments.

METHODS

The division, course, and distribution of the sensory branches that originated from the dSSN and innervated structures around the shoulder joint were examined macroscopically by dissecting 37 shoulders of 19 fresh-frozen cadavers aged of 83.0 years (range, 74-98 years).

RESULTS

The 37 dSSN provided 1 medial subacromial branch (MSAb), 1 lateral subacromial branch (LSAb), and 1 PGH branch (PGHb) to the shoulder joint. This arrangement allowed for bipolar-MSAb and LSAb-innervation of the subacromial bursa, acromioclavicular (MSAb and LSAb) and coracoclavicular (MSAb) ligaments, as well as the PGH capsule (PGHb).

CONCLUSIONS

The dSSN provided 2 subacromial branches and 1 PGHb to the shoulder joint. This arrangement allowed for bipolar-MSAb and LSAb-innervation of the subacromial bursa, acromioclavicular and coracoclavicular ligaments, as well as the PGH capsule.

Intraoperative neuromonitoring during reverse shoulder arthroplasty

BACKGROUND

The aim of this study was to evaluate the risk of nerve injury with neuromonitoring during reverse total shoulder arthroplasty.

MATERIALS

This study included 15 shoulders of 15 patients (11 females and 4 males) who underwent reverse total shoulder arthroplasty. The mean age was 74.8 ± 4.4 years. Nine shoulders had cuff tear arthropathy, 4 had massive rotator cuff tears, 2 had osteoarthritis, and 1 had rheumatoid arthritis. The somatosensory evoked potentials of the median nerve, transcranial motor evoked potentials, and free-electromyograms from 6 upper-extremity muscles were measured intraoperatively. We defined a nerve alert as 50% amplitude attenuation or 10% latency prolongation of the somatosensory evoked potentials and transcranial motor evoked potentials and sustained neurotonic discharge on free-electromyogram.

RESULTS

Thirty-one alerts were recorded in 11 patients. The axillary nerve was associated with 17 alerts. Eleven alerts occurred during the glenoid procedure and 5 alerts occurred during the humeral procedure. One patient who did not recover from the alert of the axillary nerve had clinically incomplete paralysis of the deltoid muscle.

CONCLUSION

The present findings suggest that the axillary nerve was the nerve most frequently exposed to the risk of injury, especially during glenoid and humeral implantation.

Anatomical entrapment of the dorsal scapular and long thoracic nerves, secondary to brachial plexus piercing variation

Circumscapular pain is a frequent complaint in clinical practice. The dorsal scapular and long thoracic nerves course through the neck, where they may become entrapped between or within adjacent scalene muscles. Additionally, a high frequency of brachial plexus "piercing" variants have recently been documented, and it is unclear how they influence branching patterns distally along the brachial plexus. In the project reported here we strived to identify and quantify variations in dorsal scapular nerve and long thoracic nerve secondary to brachial plexus piercing variation. Ninety brachial plexuses from human cadavers (45 female/45 male) were evaluated to identify nerve branching patterns, specifically piercing versus non-piercing variants in the brachial plexus roots and nerves. Anatomical entrapment of the dorsal scapular nerve and long thoracic nerve was found in high frequencies (60.8% and 44.6%, respectively). Anomalous brachial plexus piercing variants were associated with higher frequencies of distal nerve branches also coursing through the scalene musculature, and there was a statistically significant correlation between brachial plexus and long thoracic nerve piercings (p = 0.027). Anatomical entrapment of nerves within scalene musculature is common and may be causative factors for idiopathic circumscapular pain, dorsalgia, and dysfunction of scapulohumeral rhythm. This study revealed a link between anatomical arrangement of the brachial plexus and occurrence of long thoracic nerve entrapment, which may lead to a series of cascading neurologic effects in which affected individuals may suffer from increased incidence of thoracic outlet syndrome and long thoracic nerve entrapment resulting in additional symptoms of interscapular pain and compromised shoulder mobility.

Lateralization of the glenosphere in reverse shoulder arthroplasty decreases arm lengthening and demonstrates comparable risk of nerve injury compared with anatomic arthroplasty: a prospective cohort study

HYPOTHESIS

Grammont-style reverse shoulder arthroplasty (RSA) has an increased risk of nerve injury compared with anatomic total shoulder arthroplasty (TSA) due to arm lengthening. We hypothesized that an RSA with a lateralized glenosphere and 135° neck-shaft angle would reduce humeral lengthening and decrease the risk of nerve injury to the level of a TSA.

METHODS

The study prospectively enrolled 50 consecutive patients undergoing RSA (n = 30) or TSA (n = 20) as determined by a power analysis based on previous research for our institution. Intraoperative neuromonitoring was used to detect nerve alerts during 4 distinct stages of the procedure. Preoperative and postoperative arm lengths were measured on scaled radiographs. Patients were examined immediately postoperatively and at follow-up visits for neurologic complications.

RESULTS

Mean motor and sensory nerve alerts per case were similar for TSA and RSA (motor: TSA, 1.5 ± 2; RSA, 1.5 ± 2; P = .96; sensory: TSA, 0.6 ± 0.9; RSA, 0.2 ± 0.6; P = .06). The mean change in arm length was 3 ± 7 mm in the TSA cohort vs. 14 ± 7 mm in the RSA cohort (P = .0001). Temporary neurologic changes postoperatively were noted in 1 TSA and 1 RSA patient, amounting to a 4% incidence of nerve injury.

CONCLUSIONS

An RSA design with a lateralized glenosphere and a lower neck-shaft angle decreases arm lengthening compared with the Grammont design. The reduction in lengthening appears to eliminate the historically increased risk of neurologic injury associated with RSA relative to TSA.

Preventing brachial plexus injury during shoulder surgery: a real-time cadaveric study

BACKGROUND

Brachial plexopathy is not uncommon after shoulder surgery. Although thought to be due to stretch neuropathy, its etiology is poorly understood. This study aimed to identify arm positions and maneuvers that may risk causing brachial plexopathy during shoulder arthroplasty.

METHODS

Tensions in the cords of the brachial plexuses of 6 human cadaveric upper limbs were measured using load cells while each limb was placed in different arm positions and while they underwent shoulder hemiarthroplasty and revision reverse arthroplasty. Arthroplasty procedures in 4 specimens were performed with standard limb positioning (unsupported), and 2 specimens were supported from under the elbow (supported). Each cord then underwent biomechanical testing to identify tension corresponding to 10% strain (the stretch neuropathy threshold in animal models).

RESULTS

Tensions exceeding 15 N, 11 N, and 9 N in the lateral, medial, and posterior cords, respectively, produced 10% strain. Shoulder abduction >70° and combined external rotation >60° with extension >50° increased medial cord tension above the 10% strain threshold. Medial cord tensions (mean ± standard error of the mean) in unsupported specimens increased over baseline during hemiarthroplasty (sounder insertion [4.7 ± 0.6 N, P = .04], prosthesis impaction [6.1 ± 0.8 N, P = .04], and arthroplasty reduction [5.0 ± 0.7 N, P = .04]) and revision reverse arthroplasty (retractor positioning [7.2 ± 0.8 N, P = .02]). Supported specimens experienced lower tensions than unsupported specimens.

CONCLUSIONS

Shoulder abduction >70°, combined external rotation >60° with extension >50°, and downward forces on the humeral shaft may risk causing brachial plexopathy. Retractor placement, sounder insertion, humeral prosthesis impaction, and arthroplasty reduction increase medial cord tensions during shoulder arthroplasty. Supporting the arm from under the elbow protected the brachial plexus in this cadaveric model.

Neurologic complications of shoulder joint replacement

BACKGROUND

Little attention has been given to neurologic complications after shoulder joint replacement (SJR). Previously thought to occur infrequently, it is likely that many are not clinically recognized, and they can result in postoperative morbidity and impair the patient's recovery. The purpose of this study was to document the prevalence of nerve complications after SJR, to identify the nerves involved, and to define patient outcomes.

METHODS

This was a retrospective review of 211 SJRs in 202 patients during a 5-year period were included, with 89 male and 122 female patients at an average age of 70 years. All patients underwent a comprehensive analysis of any postoperative nerve complication, including onset, duration, investigation, treatment, and symptom resolution.

RESULTS

Of the 211 SJR procedures, 44 were identified as having sustained a nerve complication (20.9%), with 36 female (81.8%) and 8 male patients (18.2%). Reverse SJR was associated with the highest number of nerve complications. The median nerve (25 patients) and musculocutaneous nerve (8 patients) were most commonly involved. Most nerve complications were transient and resolved within 6 months. Permanent sequelae and injuries that required secondary surgical intervention were rare.

CONCLUSION

The occurrence of nerve complications after SJR is common, but almost all will fully recover. Most are transient neurapraxias involving the lateral cord of the brachial plexus. Women are more likely to be affected, as are patients who have undergone prior surgery to the affected shoulder. Most are likely to be the result of excessive traction or direct injury to the nerves during glenoid exposure.

Change in the Distance From the Axillary Nerve to the Glenohumeral Joint With Shoulder External Rotation or Abduction Position

BACKGROUND

This study investigated whether axillary nerve (AN) distance to the inferior border of the humeral head and inferior glenoid would change while placing the glenohumeral joint in different degrees of external rotation and abduction.

METHODS

A standard deltopectoral approach was performed on 10 fresh-frozen cadaveric specimens. The distance between AN and the inferior border of the humeral head and inferior glenoid while placing the shoulder in 0°, 45°, and 90° of external rotation or abduction was measured. Continuous variables for changes in AN position were compared with paired 2-tailed Student t test.

RESULTS

The mean distance between the AN and the humeral head with the shoulder in 0°, 45°, and 90° of external rotation and 0° of abduction was 13.77 mm (SD 4.31), 13.99 mm (SD 4.12), and 16.28 mm (SD 5.40), respectively. The mean distance between the AN and glenoid with the shoulder in 0°, 45°, and 90° of external rotation was 16.33 mm (SD 3.60), 15.60 mm (SD 4.19), and 16.43 (SD 5.35), respectively. The mean distance between the AN and the humeral head with the shoulder in 0°, 45°, and 90° of abduction and 0° of external rotation was 13.76 mm (SD 4.31), 10.68 mm (SD 4.19), and 3.81 mm (SD 3.08), respectively. The mean distance between the AN and glenoid with the shoulder in 0°, 45°, and 90° of abduction was 16.33 mm (SD 3.60), 17.66 mm (SD 5.80), and 12.44 mm (SD 5.57), respectively.

CONCLUSIONS

The AN position relative to the inferior aspect of the glenohumeral joint does not significantly change despite position of external rotation. Increasing shoulder abduction over 45° decreases the distance from the glenohumeral joint to the AN and should be avoided.

Neurological Complications Related to Elective Orthopedic Surgery: Part 1: Common Shoulder and Elbow Procedures

Many anesthesiologists are unfamiliar with the rate of surgical neurological complications of the shoulder and elbow procedures for which they provide local anesthetic-based anesthesia and/or analgesia. Part 1 of this narrative review series on neurological complications of elective orthopedic surgery describes the mechanisms and likelihood of peripheral nerve injury associated with some of the most common shoulder and elbow procedures, including open and arthroscopic shoulder procedures, elbow arthroscopy, and total shoulder and elbow replacement. Despite the many articles available, the overall number of studied patients is relatively low. Large prospective trials are required to establish the true incidence of neurological complications following elective shoulder and elbow surgery.

WHAT'S NEW

As the popularity of regional anesthesia increases with the development of ultrasound guidance, anesthesiologists should have a thoughtful understanding of the nerves at risk of surgical injury during elective shoulder and elbow procedures.

Anatomical and biomechanical evaluation of an intramedullary nail for fractures of proximal humerus fractures based on tuberosity fixation

BACKGROUND

For unstable proximal humerus fractures, both plates and nails may be recommended. We introduce an anterograde nail designed for the treatment of 3- and 4-parts proximal humerus fractures. The aim of this study is to compare the biomechanics of this nail versus a plate and then to analyze the relationships of the screws with the axillary nerve. Our working hypotheses are as follows: (1) this nail is biomechanically equal or better to the reference plate and (2) it does not endanger the axillary nerve.

METHODS

Biomechanical study: using 40 sawbones, a reproducible 4-part fracture was created and fixed first with an angle-stable plate for proximal humeral fracture, then fixed with the nail using 2 posterior screws. All specimens were mounted in a custom testing apparatus. Two trails were performed needing each time 5 "normal" and 5 "osteoporotic" bones.

ANATOMICAL STUDY

On 20 unpaired shoulders, a nail was inserted with all screws through a superior approach (deltoid split approach). Dissection of all shoulders was done to identify the axillary nerve. The distance between each screw and the axillary nerve or its branches was measured.

FINDINGS

The proximal humerus nail demonstrated higher values than locking plate for both stiffness and load to failure. The failure mode differs in function of the type of osteosynthesis. The lowest distance between a screw and the axillary nerve was 20.13 mm.

INTERPRETATIONS

We introduce a biomechanically efficient nail without increased neurological risks to improve the pullout strength of the screws to provide more secure fixation of proximal humeral fractures.

LEVEL OF EVIDENCE

Basic Science Study, Anatomic Cadaver Study.

Quantification of the exposure of the glenohumeral joint from the minimally invasive to more invasive subscapularis approach to the anterior shoulder: a cadaveric study

BACKGROUND

There are multiple techniques to approach the glenohumeral joint. Our purpose was to quantify the average area of the glenohumeral joint exposed with 3 subscapularis approaches and determine the least invasive approach for placement of shoulder resurfacing and total shoulder arthroplasty instruments.

METHODS

Ten forequarter cadaveric specimens were used. Subscapularis approaches were performed sequentially from split, partial tenotomy, and full tenotomy through the deltopectoral approach. Glenohumeral joint digital photographs were analyzed in Image J software (National Institutes of Health, Bethesda, MD, USA). Shoulder resurfacing and total shoulder arthroplasty instruments were placed on the humeral head, and anatomic landmarks were identified.

RESULTS

The average area of humeral head visible, from the least to the most invasive approach, was 3.2, 8.1, and 11.0 cm2, respectively. The average area of humeral head visible differed significantly according to the approach. Humeral head area increased 157% when the subscapularis split approach was compared with the partial tenotomy approach and 35% when the partial approach was compared with the full tenotomy approach. The average area of glenoid exposed from least to most invasive approach was 2.0, 2.3, and 2.5 cm2, respectively. No significant difference was found between the average area of the glenoid and the type of approach. Posterior structures were difficult to visualize for the subscapularis split approach. Partial tenotomy of the subscapularis allowed placement of resurfacing in 70% of the specimens and total arthroplasty instruments in 90%.

CONCLUSIONS

The subscapularis splitting approach allows adequate exposure for glenoid-based procedures, and the subscapularis approaches presented expose the glenohumeral joint in a step-wise manner.

LEVEL OF EVIDENCE

Anatomy study, cadaver dissection.

The evaluation of the failed shoulder arthroplasty

As the incidence of shoulder arthroplasty continues to rise, the orthopedic shoulder surgeon will be increasingly faced with the difficult problem of evaluating a failed shoulder arthroplasty. The patient is usually dissatisfied with the outcome of the previous arthroplasty as a result of pain, but may complain of poor function due to limited range of motion or instability. A thorough and systematic approach is necessary so that the most appropriate treatment pathway can be initiated. A comprehensive history and physical examination are the first steps in the evaluation. Diagnostic studies are numerous and include laboratory values, plain radiography, computed tomography, ultrasound imaging, joint aspiration, nuclear scans, and electromyography. Common causes of early pain after shoulder arthroplasty include technical issues related to the surgery, such as malposition or improper sizing of the prosthesis, periprosthetic infection, neurologic injury, and complex regional pain syndrome. Pain presenting after a symptom-free interval may be related to chronic periprosthetic infection, component wear and loosening, glenoid erosion, rotator cuff degeneration, and fracture. Poor range of motion may result from inadequate postoperative rehabilitation, implant-related factors, and heterotopic ossification. Instability is generally caused by rotator cuff deficiency and implant-related factors. Unfortunately, determining the cause of a failed shoulder arthroplasty can be difficult, and in many situations, the source of pain and disability is multifactorial.

Intraoperative nerve monitoring during total shoulder arthroplasty surgery

BACKGROUND

Nerve injury is an acknowledged complication of total shoulder arthroplasty (TSA). Although the incidence of postoperative neurological deficit has been reported to be between 1% and 16%, the true incidence of nerve damage is considered to be higher. The present study aimed to identify the rate of intraoperative nerve injury during total shoulder arthroplasty and to determine potential risk factors.

METHODS

A prospective study of nerve conduction in 21 patients who underwent primary or revision TSA was carried out over a 12-month period. Nerve conduction was monitored by measuring intraoperative sensory evoked potentials (SEP). A significant neurophysiological signal change was defined as either a unilateral or bilateral decrease in SEP signal of ≥50%, a latency increase of ≥10% or a change in waveform morphology, not caused by operative or anaesthetic technique.

RESULTS

Seven (33%) patients had a SEP signal change. The only significant risk factor identified for signal change was male sex (odds ratio 15.00, 95% confidence interval). The median nerve was the most affected nerve in the operated arm. All but one signal change returned to normal before completion of the operation and no patient had a persisting postoperative clinical neurological deficit.

CONCLUSIONS

The incidence of intraoperative nerve damage may be more common than previously reported. However, the loss of SEP signal is reversible and does not correlate with persisting clinical neurological deficits. The median nerve appears to be most at risk. Monitoring SEPs in the operated limb during TSA may be a valuable tool during TSA.

Potential axillary nerve stretching during RSA implantation: an anatomical study

Clinical and subclinical neurological injury after reverse shoulder arthroplasty (RSA) may jeopardize functional outcomes due to the risk of irreversible damage to the axillary nerve. We proposed a simple anatomical study in order to assess the macroscopic effects on the axillary nerve when lowering the humerus as performed during RSA implantation. We also measured the effect on the axillary nerve of a lateralization of the humerus. Between 2011 and 2012, cadaveric dissections of 16 shoulder specimens from nine fresh human cadavers were performed in order to assess the effects on the axillary nerve after the lowering and lateralization of the humerus. We assessed the extent of stretching of the axillary nerve in four positions in the sagittal plane [lowering of the humerus: great tuberosity in contact with the acromion (position 1), in contact with the upper (position 2), middle (position 3) and lower rim of the glenoid (position 4)] and three positions in the frontal plane [lateralization of the humerus: humerus in contact with the glenoid (position 1), humerus lateralized 1 cm (position 2) and 2 cm (position 3)]. When the humerus was lowered, clear macroscopical changes appeared below the middle of the glenoid (the highest level of tension). As regards the lateralization of the humerus, macroscopic study and measurements confirm the absence of stretching of the nerve in those positions. Lowering of the humerus below the equator of the glenoid changes the course and tension of the axillary nerve and may lead to stretching and irreversible damage, compromising the function of the deltoid. Improvements in the design of the implants and modification of the positioning of the glenosphere to avoid notching and to increase mobility must take into account the anatomical changes induced by the prosthesis and its impact on the brachial plexus. Level of Evidence and study type Level IV.

Surgical anatomy of the axillary nerve branches to the deltoid muscle

Variations in the innervation of the posterior deltoid muscle by the anterior branch of the axillary nerve have been reported. The objective of this study is to clarify the anatomy of the axillary nerve branches to the deltoid muscle. One hundred and twenty-nine arms (68 right and 61 left) from 88 embalmed cadavers (83 male and 46 female) were included in the study. The anterior and posterior branches of the axillary nerve were identified and their lengths were measured from the point of emergence from the axillary nerve to their terminations in the deltoid muscle. In all cases, the axillary nerves split into two branches (anterior and posterior) within the quadrangular space and none split within the deltoid muscle. In all specimens, the anterior and middle parts of the deltoid muscle received their nerve supplies from the anterior branch of the axillary nerve. The posterior part of the deltoid muscle was supplied only by the anterior branch of the axillary nerve in 2.3% of the specimens, from the posterior branch in 8.5%, and from both branches in 89.1%. There were two sub-branches of the anterior branch in 4.7% of the specimens. The anterior branch of the axillary nerve supplied not only the anterior and middle parts of the deltoid muscle but also the posterior part in most cases (91.5%).

Total shoulder arthroplasty

Shoulder arthroplasty has been the subject of marked advances over the last few years. Modern implants provide a wide range of options, including resurfacing of the humeral head, anatomic hemiarthroplasty, total shoulder arthroplasty, reverse shoulder arthroplasty and trauma-specific implants for fractures and nonunions. Most humeral components achieve successful long-term fixation without bone cement. Cemented all-polyethylene glenoid components remain the standard for anatomic total shoulder arthroplasty. The results of shoulder arthroplasty vary depending on the underlying diagnosis, the condition of the soft-tissues, and the type of reconstruction. Total shoulder arthroplasty seems to provide the best outcome for patients with osteoarthritis and inflammatory arthropathy. The outcome of hemiarthroplasty for proximal humerus fractures is somewhat unpredictable, though it seems to have improved with the use of fracture-specific designs, more attention to tuberosity repair, and the selective use of reverse arthroplasty, as well as a shift in indications towards internal fixation. Reverse shoulder arthroplasty has become extremely popular for patients with cuff-tear arthropathy, and its indications have been expanded to the field of revision surgery. Overall, shoulder arthroplasty is a very successful procedure with predictable pain relief and substantial improvements in motion and function.

Anatomical considerations of subcoracoid neurovascular structures in anterior shoulder reconstruction

Anterior shoulder surgery, using open or arthroscopic technique, places subcoracoid neurovasculature at risk. This study examines the relationships of the brachial plexus and axillary artery to four bony landmarks and provides clinical correlations for anterior shoulder surgery. The musculocutaneous nerve (MN), posterior cord (PC), lateral cord (LC), and axillary artery (AA) were identified in 27 shoulders. Minimum distances (mm) were measured between neurovasculature and the coracoid tip, anterior midglenoid, inferior surface of the midclavicle, and anteromedial aspect of the acromioclavicular joint. Average distances from the coracoid to the MN, PC, LC, and AA were 69.7 ± 31.6, 50.5 ± 9.2, 41.8 ± 9.4, and 60.0 ± 8.0 mm, respectively; from the glenoid equator to the MN, PC, LC, and AA were 61.5 ± 38.5, 37.0 ± 6.1, 35.2 ± 8.7, and 45.2 ± 7.1 mm, respectively; from the midclavicle to the MN, PC, LC, and AA were 114.1 ± 33.9, 62.0 ± 13.6, 56.0 ± 19.7, and 69.9 ± 7.8 mm, respectively; and from the AC joint to the MN, PC, LC, and AA were 112.7 ± 36.5, 87.9 ± 10.6, 84.0 ± 12.0, and 100.9 ± 1.0 mm, respectively. The lateral cord was the closest structure to each bony landmark. The musculocutaneous nerve was the furthest structure from each bony landmark. Open procedures using a deltopectoral approach with the shoulder in the anatomical position, such as the Neer capsular shift and Warner capsular reconstruction, can use these results to prevent direct or retraction injuries. Results indicate a potential safe zone of 30 mm in diameter around the anteromedial coracoid tip for anteroinferior portal placement.

Treatment of chronic glenoid defects in the setting of recurrent anterior shoulder instability: a systematic review

OBJECTIVE

The purpose is to systematically evaluate the literature regarding treatment of chronic glenoid bone defects in the setting of recurrent anterior shoulder instability to determine if, from an evidence-based outcomes approach, one technique may be recommended over the other.

METHODS

PubMed 1966-2009, Embase 1980-2009, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials databases were searched for human studies in English. Keywords were osseous glenoid defects, glenoid bone grafting, Latarjet procedure, iliac crest and glenoid defects, and glenoid rim fractures. Inclusion criteria were all articles evaluating chronic glenoid deficiency in the setting of recurrent anterior glenohumeral instability. Exclusion criteria were surgical techniques not reporting follow-up, glenoid rim fractures treated by open reduction internal fixation, and investigations not quantifying glenoid deficiency assessments.

RESULTS

Six articles met all inclusion and exclusion criteria. All articles were level IV (case series), most (5/6) were retrospective. Multiple techniques involving coracoid transfer and allograft or autograft reconstruction have been described for management of chronic glenoid deficiency. Lack of high level evidence in the form of prospective randomized trials limits our ability to recommend one technique over another. The 6 techniques reviewed here were all effective at preventing recurrent instability.

CONCLUSIONS

Chronic glenoid deficiency in the setting of recurrent anterior instability is an extremely challenging problem. There remains a lack of strong evidence guiding the surgeon in the decision-making process. Additional research is needed to optimize the preoperative glenoid defect assessment, further evaluate the reconstruction techniques, and follow the long-term effects of reconstruction on the development of glenohumeral arthrosis.

Review of the surgical anatomy of the axillary nerve and the anatomic basis of its iatrogenic and traumatic injury

The axillary nerve is invariably reported to be one of the most commonly injured nerves during surgical procedures of the shoulder, and the importance of protecting it cannot be overemphasized. Many researchers have tried to identify safe regions, but the results vary among published studies. The axillary nerve may also be injured during acute trauma to the shoulder or by chronic repeated trauma as has been described in the quadrilateral space syndrome. The nerve injury may occur together with shoulder dislocation and rotator cuff tear, thus comprising the so-called "unhappy triad" of the shoulder joint. Simple attention to potential variations in the origin and course of the axillary nerve and its relationship to the shoulder capsule and having a precise knowledge of "safe zones" during operations can enhance clinical outcomes. The objective of this review, therefore, is to discuss the surgical anatomy of the axillary nerve and further emphasize the clinical importance of the its injury following shoulder trauma.

Axillary nerve palsy after retrograde humeral nailing: clinical confirmation of an anatomical fear

INTRODUCTION

Locked antegrade or retrograde nailing of humeral shaft and proximal humerus fractures is a well established treatment option. Anatomic-morphological studies revealed a potential high risk of axillary nerve injury within proximal interlocking screw insertion. However, clinical experiences do not seem to confirm this, as there is a lack of interlocking screw insertion associated axillary lesions in literature.

CASE REPORT

We report about a 69-year-old man with a humeral shaft fracture (AO-type 12-A3) stabilized by a retrograde implanted interlocking nail. Proximal interlocking screw insertion was performed in a posterior-to-anterior direction. The fracture healed uneventfully. In a follow-up examination 2 years later, an atrophy and paralysis of the deltoid muscle were visible. Electrophysiological evaluation confirmed an isolated axillary nerve injury. Nevertheless, the patient showed good functional recovery with almost free range of motion.

CONCLUSION

Even for clinical practise proximal interlocking screw insertion is associated with a substantial risk of axillary nerve injury. Particularly for posterior-to-anterior screw insertion anatomic conditions should be considered. In spite of axillary nerve lesion, recovery of almost full shoulder function is possible by compensating the loss of deltoid function by rotator cuff muscles.

Relationships of the musculocutaneous nerve and the coracobrachialis during coracoid abutment procedure (Latarjet procedure)

PURPOSE

The aim of this study was first to define first the anatomical relationships between the musculocutaneous nerve and the coracobrachialis, and then the induced modifications of these relationships by a preglenoid transposition of the vertical part of the coracoid process.

MATERIALS AND METHODS

Twenty-one embalmed adult trunks and upper limb were dissected. First the coracobrachialis and the musculocutaneous nerve were identified through a deltopectoral approach. We measured the distances between the lateral cord of the brachial plexus and the entry point of the nerve, between the inferior tip of the tip of the coracoid process and the penetration of the nerve or its twigs, and finally the angle between the general axis of the coracobrachialis and the axis of the musculocutaneous nerve. The same measures were performed after the coracoid bone block abutment.

RESULTS

Proximal motor branches destined to the coracobrachialis varied from 0 to 3. Mean distance between the lateral cord of the brachial plexus and entry point of the nerve into the muscle was 47.2 mm before and 48.43 mm after the coracoid transfer. Mean angulations between the nerve and the muscle was 121 degrees before and 136 degrees after the transfer of the coracoid process. Mean distance between the inferior tip of the coracoid process and entry point of the nerve into the muscle was 55.7 mm, reduced to 48.6 mm after the coracoid transposition. Finally, the distance between the tip of the coracoid and the first motor twig entering the coracobrachialis was less than 50 mm in 75% of the cases with a mean value of 40.6 mm.

CONCLUSIONS

Lesion of the musculocutaneous nerve is a known complication of the coracoid bone block abutment procedure (Latarjet-Bristow). From this study we know that they are due to lengthening of the nerve and modification of the penetration angle of the nerve into the coracobrachialis. We also infer that some motor nerve destined to the coracobrachialis might be damaged during the proximal medial release of the muscle after the detachment of the pectoralis minor muscle.

[Knee and shoulder arthroscopy. Positioning and thermal injuries]

Intraoperative positioning injuries during shoulder- and knee arthroscopy are rare complications and affect mainly nerves and soft tissue. Although the majority of these complications are reversible, in some cases serious negative consequences for the patient persist. This article describes the frequency of several positioning injuries including their prevention and the appropriate treatment. The legal responsibilities are illustrated as well as the importance of an intense preoperative investigation of preexisting diseases and possible risk factors. Furthermore, a review of possible thermal injuries of the patient during arthroscopy caused by e.g. electrosurgical instruments or the cold light source, is given as well as prevention strategies.

[Reduction of glenoid rim fractures after primary shoulder dislocation in external rotation]

The treatment of anterior glenoid rim fractures depends on the size of the fracture and the articular surface involved. The operative treatment is open or arthroscopic refixation. In cases with small fragments and a stable shoulder nonoperative treatment is recommended. In patients with a primary shoulder dislocation immobilization in external rotation has been showed to improve the position of the displaced labrum on the glenoid rim. However, whether external rotation can reduce displaced glenoid rim fractures is not known. With the use of CT the repositioning of a glenoid rim fracture in a single patient in external rotation is evaluated.A 26-year-old patient with an anterior glenoid rim fracture after a primary shoulder dislocation was referred to our shoulder service. After initial reduction a CT scan in internal and external rotation of the involved shoulder was performed. In the external rotation CT the glenoid rim fracture was reduced in anatomic position. The patient was immobilized in a 30 degrees external rotation brace for 4 weeks. Six weeks after trauma the internal rotation CT showed the fracture healed in the anatomic position. At the 1-year follow-up the Constant Score and the Rowe Score were 100 points each. In patients with anterior glenoid rim fractures immobilization of the shoulder in external rotation seems to allow a reduction of the fracture. A study with a large number of patients is under way to evaluate long-term results.

Effects of the adducted or abducted position of the arm on the course of the musculocutaneous nerve during anterior approaches to the shoulder

Nerve injury is a common complication during anterior shoulder surgery. The purpose of the study was to evaluate the musculocutaneous nerve (MN) anatomically and to clarify the relationship of the MN to the glenoid labrum and coracoid process in different arm positions. The study was carried out on 40 shoulders of 20 adult cadavers fixed in 10% formaldehyde. The minimum distance of the MN at the entrance point of the nerve into the coracobrachialis to the anteromedial aspect of the coracoid tip and the distance between the MN and the top, middle, and inferior points of the glenoid labrum were measured. All measurements were performed with a digital caliper while the arm was in a neutral position, 45 degrees and 90 degrees of abduction, 90 degrees of abduction-internal rotation and 90 degrees of abduction-external rotation to evaluate whether arm position effects the results statistically or not. The results demonstrated that the position of the arm significantly changes the distance between the coracoid process (CP) and the MN or its cord. The change in distance between the glenoid labrum and the MN or its cord was also statistically significant. The distance between the CP and MN was greatest when the arm was abducted to 45 degrees (mean 3.4 cm) and least when the arm was positioned to 90 degrees of abduction-internal rotation (mean 2.0 cm). While the distance between the MN and the coracoid process was least at 90 degrees of abduction and internal rotation, the distance between the MN and glenoid labrum was lest with 90 degrees of abduction and external rotation. The distance between the glenoid labrum and MN was greatest with 45 degrees of abduction. The results of this study might be of use in avoiding the MN especially during Bristlow operations and certain rotator cuff procedures. Transferring the coracoid process during Bristow operations or placing arthroscopic portals when the arm is abducted to 45 degrees appears to be the safest position in terms of MN injury. Based on our results, when the arm needs to be abducted to 90 degrees during operation, externally rotating it may decrease the tension on the brachial plexus thus increasing the distance between the MN and the portals or retractors.

The sensory branch distribution of the suprascapular nerve: an anatomic study

The suprascapular nerve is responsible for most of the sensory innervation to the shoulder joint and is potentially at risk during surgery. In this study, 31 shoulders in 22 cadavers were dissected to investigate the sensory innervation of the shoulder joint by the suprascapular nerve, with special reference to its sensory branches. In 27 shoulders (87.1%), a small sensory branch was observed that splits off from the main stem of the suprascapular nerve proximal (48.2%), inferior (40.7%), or distal (11.1%) to the transverse scapular ligament. This percentage is considerably higher than has been previously found. In 74.2% of the shoulders, an acromial branch was also found, originating just proximal to the scapular neck, running to the infraspinatus tendon. These cadaveric results indicate that sensory branches to the shoulder joint are more common and numerous than previously described and therefore should be considered in shoulder surgery and nerve blocks to this area.

Difficultés du transfert d’information en vue d’un consentement éclairé

PURPOSE OF THE STUDY

Delivering information to the patient, an ethical obligation recognized for years, has recently become a legal obligation. Proof of information delivery has become the legal responsibility of the surgeon. We conducted a prospective study to evaluate the quality of information transfer by assessing patient comprehension of information delivered in an orthopedic surgery unit.

MATERIAL AND METHODS

All patients attending consultations before undergoing arthroscopic treatment for rotator cuff tendinopathy were enrolled in this study when the consultation was conducted in the presence of an observer. Two questionnaires, one for the patient and one for the surgeon, were used to collect given information about the pathological condition, the modalities of treatment, and the expected results of the treatment and its complications.

RESULTS

All 21 patients included in the study considered they had been well informed and that they had understood their pathological condition as well as the complications of the proposed treatment. However, agreement between their stated comprehension and the information delivered was poor, varying from 15 to 50%. Furthermore, 90% of the patients stated they had understood the potential complications of the surgical procedure, despite the fact that the consulting surgeons had not (generally) provided information on such complications.

DISCUSSION

There is a gap between what the surgeon says (or thinks he/she says) and what the patient understands. Potential biases in this study (non-unbiased observer) might explain this discordance which was probably related to the unequal relationship between the patient and the physician for any consultation. Therefore, the basis of informed consent cannot be found in the details concerning complications actually delivered to the patient. Surgeons must become aware that the patients understand very little of their explanations. This does not mean that the information should not be delivered but on the contrary that it must be. The important point is not necessarily the information content but rather the quality of the human relationship enabling information transfer.

Schwerwiegende Komplikation nach perkutan-transaxillärer Verschraubung einer Glenoidfraktur

The common treatment for glenoid rim fractures has been open reduction and internal fixation by a deltopectoral approach. Minimally invasive procedures with percutaneous transaxillary manipulation have a high risk for neurovascular damage. In a single case we demonstrate the possible complications associated with percutaneous refixation of a glenoid rim fracture. A 34-year-old patient with an anterior glenoid rim fracture was referred to our shoulder service after percutaneous transaxillary fixation of the fracture of the glenoid. He presented a dislocated fracture with joint infection and damage of the axillary nerve and artery. During revision surgery, joint infection with Staphylococcus aureus, dislocation of the fracture, aneurysm of the axillary artery, and a lesion in continuity of the axillary nerve were diagnosed. The fragment was excised and the capsule reattached to the remaining glenoid rim. The aneurysm was resected with an end-to-end anastomosis. The outcome was a noninfected and stable shoulder with a limited range of motion. In patients with a glenoid rim fracture with more then 21% of the glenoid fossa involved, refixation of the fracture is recommended. Open reduction and internal fixation is the gold standard. In some cases arthroscopic repair is possible. Percutaneous transaxillary manipulation is not recommended.

Nerve injury and regional anaesthesia

PURPOSE OF REVIEW

In recent years there has been a renewed interest in regional anaesthesia, particularly peripheral nerve blockade, not only to improve the patient's well being, but also to meet the requirements of modern orthopaedic surgery. Nerve injury in this context is the complication most feared by the patient, the anaesthesiologist and the surgeon.

RECENT FINDINGS

To date, data dealing with the incidence of nerve injury in regional anaesthesia have almost exclusively been retrieved from close claims analysis. Recently, prospective, well controlled studies have shown that severe neurologic complications rarely occur: for the upper extremity, an incidence of 0.2-1% has been reported. New insights into the mechanisms of local anaesthetic neurotoxicity have demonstrated that ropivacaine has the least potential for neurotoxicity. Administration of the lowest possible concentrated solution of local anaesthetic is likely to be even less neurotoxic. The role of local anaesthetics in the development of apoptosis is nowadays well recognized. The consequences of other factors, such as nerve stretching and compression, in the pathology of nerve damage are emphasized.

SUMMARY

Significant advances have been made in regional anaesthesia in the past 10 years. The introduction of catheter techniques has cleared the way for better regional anaesthetic and analgesic blocks. Studies dealing with placement of perineural catheters show that the catheter does not increase neurological complications. Properly performed, regional anaesthesia is a safe form of anaesthesia and the benefits far outweigh the risks.