Surgical anatomy of the radial nerve in the deltopectoral approach for revision shoulder arthroplasty and periprosthetic fracture fixation: a cadaveric study

Cement-within-cement technique in revision reverse shoulder arthroplasty: A systematic review of biomechanical data, and clinical outcomes

Background

The purpose of this research was to systematically review and summarize the existent literature on the use of the cement-within-cement technique for revision reverse shoulder arthroplasty (RSA).

Methods

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed/Medline, Scopus, and EMBASE databases were searched for relevant studies. We included clinical studies in which patients underwent RSA revision using the cement-within-cement method for the humeral component, and studies that evaluated the biomechanical performance or described the surgical technique. The methodological risk of bias was assessed using the methodological index for non-randomized studies scale.

Results

The search yielded 516 records, of which two clinical and one biomechanical study met the inclusion criteria, involving 133 patients and 20 synthetic humeri. The intraoperative complication rate was 18%, all of which involved humeral fractures. The postoperative complication rate was 18% among 35 patients. The combined re-revision rate was 9%, with a reported humeral component survival rate of 100% at 2 years and 96% at 5 years. Periprosthetic fractures (1.5%) and humeral stem loosening (1.5%) led to re-revision surgeries in all cases. All studies reported improved patient-reported outcomes and range of motion. The biomechanical study demonstrated increased rotational stability in models that used larger humeral stems.

Conclusions

The cement-within-cement method is a viable option for revision RSA, showing positive outcomes in terms of stability, range of motion, and clinical functional scores. The complication rate is similar to that of other revision strategies; however, the prevalence of intraoperative humeral fractures may be higher. Nevertheless, future studies with larger sample sizes and longer follow-up periods are needed to refine patient selection, determine the efficacy of long-term use, and identify factors that may influence outcomes after the cement-within-cement revision technique. Further research on an optimized stem fixation strategy is needed to improve outcomes and reduce avoidable complications.

Level of evidence

Level IV, Systematic reviews.

Patient-specific articulating spacer for two-stage shoulder arthroplasty exchange

OBJECTIVE

Two-stage exchange with an antibiotic-loaded polymethylmethacrylate (PMMA) spacer is standard treatment for chronic periprosthetic joint infection of the shoulder. We present a safe and simple technique for patient-specific spacer implants.

INDICATION

(Chronic) periprosthetic joint infection of the shoulder.

RELATIVE CONTRAINDICATIONS

Known allergy against components of PMMA bone cements. Inadequate compliance for two-stage exchange. Patient is unfit to undergo two-stage exchange.

SURGICAL TECHNIQUE

Hardware removal, histologic and microbiologic samples, and debridement. Preparation of targeted or calculated antibiotic-loaded PMMA. Tailoring of patient-specific spacer. Spacer implantation.

POSTOPERATIVE MANAGEMENT

Rehabilitation protocol. Antibiotic treatment. Reimplantation after successful eradication of infection.

Evaluation and treatment of postoperative periprosthetic humeral fragility fractures

Postoperative periprosthetic humeral shaft fractures represent a growing and difficult complication to treat given the aging patient population and associated bone loss. Determining the best treatment option is multifactorial, including patient characteristics, fracture pattern, remaining bone stock, and implant stability. Possible treatment options include nonoperative management with bracing or surgical intervention. Nonoperative treatment has been shown to have higher nonunion rates, thus should only be selected for a specific patient population with minimally displaced fractures or those that are unfit for surgery. Surgical management is recommended with prosthetic loosening, fracture nonunion, or failure of nonoperative treatment. Surgical options include open reduction and internal fixation, revision arthroplasty, or hybrid fixation. Careful evaluation, decision making, and planning is required in the treatment of these fractures.

Spatial Anatomy of the Radial Nerve in the Extended Deltopectoral Approach

The goal of this study was to define safe zones to prevent radial nerve injury in an extended deltopectoral approach. Relative distances of the upper margin (UMRN) and lower margin (LMRN) of the radial nerve to the proximal and distal borders of the pectoralis major and deltoid insertions were measured in 20 cadaveric arms. Four proximal humeral zones were identified (zone I, proximal border of the pectoralis major tendon to the proximal border of the deltoid tendon; zone II, proximal border of the deltoid tendon to the distal border of the pectoralis major tendon; zone III, distal border of the pectoralis major tendon to the distal border of the deltoid tendon; and zone IV, distal to the distal border of the deltoid tendon). On fluoroscopic measurement, mean distances between the UMRN and the proximal border of the pectoralis major tendon and the proximal border of the deltoid tendon were 71.6±2.1 mm and 26.2±2.5 mm, respectively. The incidence of the radial nerve in the spiral groove within each defined zone was as follows: zone I, 0%; zone II, 50%; zones III and IV, 100%. There was a significant association between anatomic zone and radial nerve entry into the spiral groove, χ²(3, N=88)=64.53, P<.001. The proximal border of the pectoralis major tendon to the proximal border of the deltoid tendon (zone I) is a safe location to avoid injury to the radial nerve. We recommend placing cerclage wires proximal to zone I from lateral to medial to avoid entrapment of the radial nerve. [Orthopedics. 2023;46(1):e31-e37.].

Intraoperative and early postoperative complications of reverse shoulder arthroplasty: A current concepts review

Background

Reverse shoulder arthroplasty is a common procedure performed for a variety of shoulder pathologies.

Aims and objectives

This current concept review evaluates the intraoperative and early postoperative complications, with a specific focus given to neurological and vascular injury, fracture, dislocation and venous thromboembolism.

Conclusion

A detailed knowledge of potential complications will allow surgeons to mitigate risk and maximise outcomes.

Triceps and cutaneous radial nerve branches investigated via an axillary anterior arm approach: new findings in a fresh-cadaver anatomical study

OBJECTIVE

The authors sought to describe the anatomy of the radial nerve and its branches when exposed through an axillary anterior arm approach.

METHODS

Bilateral upper limbs of 10 fresh cadavers were dissected after dyed latex was injected into the axillary artery.

RESULTS

Via the anterior arm approach, all triceps muscle heads could be dissected and individualized. The radial nerve overlaid the latissimus dorsi tendon, bounded by the axillar artery on its superior surface, then passed around the humerus, together with the lower lateral arm and posterior antebrachial cutaneous nerve, between the lateral and medial heads of the triceps. No triceps motor branch accompanied the radial nerve's trajectory. Over the latissimus dorsi tendon, an antero-inferior bundle, containing all radial nerve branches to the triceps, was consistently observed. In the majority of the dissections, a single branch to the long head and dual innervations for the lateral and medial heads were observed. The triceps long and proximal lateral head branches entered the triceps muscle close to the latissimus dorsi tendon. The second branch to the lateral head stemmed from the triceps lower head motor branch. The triceps medial head was innervated by the upper medial head motor branch, which followed the ulnar nerve to enter the medial head on its anterior surface. The distal branch to the triceps medial head also originated near the distal border of the latissimus dorsi tendon. After a short trajectory, a branch went out that penetrated the medial head on its posterior surface. The triceps lower medial head motor branch ended in the anconeus muscle, after traveling inside the triceps medial head. The lower lateral arm and posterior antebrachial cutaneous nerve followed the radial nerve within the torsion canal. The lower lateral brachial cutaneous nerve innervated the skin over the biceps, while the posterior antebrachial cutaneous nerve innervated the skin over the lateral epicondyle and posterior surface of the forearm. The average numbers of myelinated fibers were 926 in the long and 439 in the upper lateral head and 658 in the upper and 1137 in the lower medial head motor branches.

CONCLUSIONS

The new understanding of radial nerve anatomy delineated in this study should aid surgeons during reconstructive surgery to treat upper-limb paralysis.

Neurologic complications in primary anatomic and reverse total shoulder arthroplasty: A review

Neurologic injury during shoulder replacement is one of the less common complications of the procedure, however the clinical implications can be significant. The purpose of this paper is to review the current literature on neurologic complications in various types of shoulder replacement and provide recommendations regarding avoidance, evaluation, and management of these complications.

Prevention and Treatment of Nerve Injuries in Shoulder Arthroplasty

➤

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.

➤

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.

Iatrogenic Nerve Palsy Occurs With Anterior and Posterior Approaches for Humeral Shaft Fixation

OBJECTIVE

To determine if surgical approach impacts the rate of nerve palsy after plate fixation of humerus shaft fractures and whether or not iatrogenic nerve palsy recovers in similar ways to preoperative palsy.

DESIGN

Retrospective.

SETTING

Two trauma centers.

PATIENTS

Patients 18+ years of age with nonpathologic, extra-articular humerus shaft fractures (OTA/AO 12A/B/C and 13A2-3) treated with plate fixation.

INTERVENTION

Plate fixation of humerus shaft fractures, from 2008 to 2016.

MAIN OUTCOME MEASUREMENT

Rate of iatrogenic nerve palsy by a surgical approach and injury characteristics.

RESULTS

Two hundred sixty-one humeral shaft fractures were included. The rate of preoperative palsy was 19%. Radial nerve palsy (RNP) was present in 18%. Iatrogenic RNP occurred in 12.2% and iatrogenic ulnar palsy in 1.2%. Iatrogenic palsy occurred in 15.6% of middle and 15% of distal fractures, with fracture location significantly different in those developing RNP (P = 0.009). Iatrogenic RNP occurred in 7.1% of anterolateral, 11.7% of posterior triceps-splitting, and 17.9% of posterior triceps-sparing approaches (P = 0.11). Follow-up data were available for 139 patients at an average of 12 months. Preoperative RNP resolved less often than iatrogenic RNP, in 74% versus 95% (P = 0.06). Time to resolution was longer for preoperative RNP, at 5.5 versus 4.1 months (P = 0.91). Twenty-two percent with preoperative RNP underwent tendon transfer or wrist fusion, versus 0% after iatrogenic RNP (P = 0.006).

CONCLUSION

Iatrogenic RNP is not uncommon with humeral fracture fixation and occurs at similar rates in anterior and posterior approaches and with midshaft and distal fractures. Iatrogenic RNP had a high rate of recovery. Preoperative RNP more often requires surgery for unresolved palsy.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Surgically relevant anatomy of the axillary and radial nerves in relation to the latissimus dorsi tendon in variable shoulder positions: A cadaveric study

BACKGROUND

The purpose of this study was to define the relationship of the axillary and radial nerves, particularly how these are affected with changing arm position.

METHODS

Twenty cadaveric shoulders were dissected, identifying the axillary and radial nerves. Distances between the latissimus dorsi tendon and these nerves were recorded in different shoulder positions. Positions included adduction/neutral rotation, abduction/neutral rotation for the axillary nerve, adduction/internal rotation, adduction/neutral rotation, adduction/external rotation, and abduction/external rotation for the radial nerve.

RESULTS

Width of the latissimus tendon at its humeral insertion was 29.3 ± 5.7 mm. Mean distance from the latissimus insertion to the axillary nerve in adduction/neutral rotation was 24.2 ± 7.1 mm, the distance increased to 41.1 ± 9.8 mm in abduction/neutral rotation. Mean distance from the latissimus insertion to the radial nerve was 15.3 ± 5.5 mm with adduction/internal rotation, 25.8 ± 6.9 mm in adduction/neutral rotation, and 39.5 ± 6.8 mm in adduction/external rotation. Mean distance increased with abduction/external rotated 51.1 ± 7.4 mm.

CONCLUSIONS

Knowing the axillary and radial nerve locations relative to the latissimus dorsi tendon decreases the risk of iatrogenic nerve injury. Understanding the dynamic nature of these nerves related to different shoulder positions is critical to avoid complications.

The router bit extraction technique for removing a well-fixed humeral stem in revision shoulder arthroplasty

Aims

A number of methods have been described to remove a well-fixed humeral implant as part of revision shoulder arthroplasty. These include the use of cortical windows and humeral osteotomies. The router bit extraction technique uses a high-speed router bit to disrupt the bone-implant interface. The implant is then struck in a retrograde fashion with a square-tip impactor and mallet. The purpose of this study was to determine the characteristics and frequency of the different techniques needed for the removal of a well-fixed humeral stem in revision shoulder arthroplasty.

Patients and Methods

Between 2010 and 2018, 288 revision shoulder arthroplasty procedures requiring removal of a well-fixed humeral component were carried out at a tertiary referral centre by a single surgeon. The patient demographics, indications for surgery, and method of extraction were collected.

Results

Of the 288 revisions, 284 humeral stems (98.6%) were removed using the router bit extraction technique alone. Four humeral stems (1.39%) required an additional cortical window. Humeral osteotomy was not necessary in any procedure. Most of the humeral stems removed (78.8%) were cementless. Of the four humeral stems that required a cortical window, three involved removal of a hemiarthroplasty. Two were cemented and two were cementless.

Conclusion

The router bit extraction technique removed a well-fixed humeral component in a very high proportion of patients (98.6%). This method allows surgeons to avoid more invasive approaches involving a cortical window or humeral osteotomy, and their associated complications. Cite this article: Bone Joint J 2019;101-B:1280–1284

Safe Zones for Cerclage Wiring of the Humeral Diaphysis

Cerclage wiring of the humeral diaphysis entails particular danger to the radial nerve and the deep brachial artery. We sought to delineate safe zones for minimally invasive cerclage wiring of the humeral diaphysis, specifically in relation to the radial nerve and accompanying vasculature. Cerclage wires were percutaneously inserted into three groups of fresh-frozen cadaveric humeri. Group 1-proximal midshaft humerus at 30% of humeral height (n = 4); Group 2-midshaft spiral groove at 45% of humeral height (n = 4); and Group 3-distal midshaft humerus at 60% of humeral height (n = 4). Subsequently, an extensive surgical exploration of the arteries and nerves around the humerus was performed, noting any disturbance to the vessels or nerves and measuring the distance from the cerclage wire to the radial nerve. Neurovascular structures were injured in 75% of specimens when the cerclage wire was inserted at the level of the spiral groove. Both posterior structures, e.g. the radial nerve and the deep brachial artery, and medial structures, e.g., the median nerve and brachial artery, were incarcerated. Application of the cerclage at 30% or 60% of humeral height did not cause neurovascular injury. Minimally invasive application of the cerclage wire at the spiral groove, which is at 45% of humeral height, is likely to cause injury to neurovascular structures. Application of the cerclage at the proximal or distal midshaft humeral areas is associated with less risk of such injury. Clin. Anat. 33:552-557, 2020. © 2019 Wiley Periodicals, Inc.