6 Preoperative Work-up and Surgical Approaches for Reverse Shoulder Arthroplasty
Abstract
Comprehensive preoperative work-up for reverse shoulder arthroplasty (RSA) is critical in order to achieve a successful outcome following surgery. A thorough patient history must be combined with clinical and radiographic information to guide the orthopaedic surgeon to both indicate a patient for RSA and execute surgery in a safe manner with satisfactory results. Preoperative counseling by the treating surgeon is also a key component in order to guide patient expectations in order to ensure a successful outcome. RSA is typically performed through either a deltopectoral or an anterosuperior approach. A description of each approach with technical pearls are described this chapter.
6.1 Introduction
Indications for reverse shoulder arthroplasty (RSA) have expanded significantly in recent years and include rotator cuff arthropathy, massive irreparable rotator cuff tears without glenohumeral arthritis, primary glenohumeral arthritis with a severe biconcave (B2) glenoid, failed hemiarthroplasty/total shoulder arthroplasty, and fracture sequelae. These indications have been further described in greater detail in Chapter 5 of this book. Once a patient is indicated for RSA, many important pieces of information must be obtained from the patient’s history, physical examination, and radiographic imaging to assist with appropriate preoperative, intraoperative, and postoperative planning/decision making. There are many factors influencing the outcomes of RSA. These factors include but are not limited to the indication for surgery, the surgeon’s experience, characteristics of the implant, characteristics of the surgical technique, type of approach, and postoperative rehabilitation. 1
Preoperative assessment of the glenoid is critical to determine whether a glenoid could be placed in a standard fashion or with bone or metal augmentation. Additionally, the bony anatomy should be critically assessed to determine if any special considerations are required during surgery. Understanding the intricacies of the surgical approach technique during RSA aids in appropriate exposure and proper positioning of components to decrease the risk of instability, impingement, and loosening. 2
6.2 History
The majority of patients undergoing RSA have pain and limited range of motion (ROM) that may limit vocational, recreational, or daily activities as a result of irreparable damage to the rotator cuff. This typically leads to an unstable center of rotation for the glenohumeral joint. The extent of pain, weakness, instability, and stiffness varies with the underlying etiology and is important to recognize preoperatively using history and physical exam. Past medical, surgical, and social history along with appropriate patient expectations should be determined before surgery in order to determine if RSA is a good surgical option as well as to achieve a successful outcome. The patient’s history may identify risk factors associated with poor functional improvement and early revision rate, such as younger age (< 65 years), smoking, obesity, high preoperative function, and neurologic dysfunction. 3 , 4 Each hospital should establish a hazard mitigation scale based on the best available medical evidence according to each risk factor:
Age: Increasing age has been correlated with an extended length of stay after elective shoulder arthroplasty. In addition, patients younger than 65 years have increased risk for early revision rate. 5 , 6
Transfusion risks and cardiovascular diseases: The overall blood transfusion rate in the United States in patients undergoing shoulder replacement is 6.7%. 7 Lower preoperative hemoglobin (less than 12.5 g/dL), higher intraoperative blood loss, age, and a number of comorbid conditions are all considered predictive of the need for transfusion after shoulder arthroplasty. Primary RSA is not considered a risk factor for postoperative blood transfusion, but revision RSA has shown a significantly higher rate of complications. 8 , 9 , 10 Some patients have increased risk of intraoperative bleeding, such as patients with liver disease, coagulation disorders, thrombocytopenia systolic hypertension without control, and those taking anticoagulant medications preoperatively. 11 Authors recommend that patients with coronary disease, heart failure, cerebrovascular disease, diabetes mellitus, and arrhythmias should be evaluated and managed by an internal medicine physician before undergoing RSA.
Renal function: Glomerular filtration rate < 60 mL/min could be a risk factor for complications during intraoperative and postoperative treatment in patients undergoing RSA.
Nutritional status: Malnutrition Universal Screening Tool (MUST) is a useful tool to identify patients with poor nutritional status. 12 A MUST score of 2 or more suggests that the patient needs further optimization before undergoing RSA. Obesity is considered a risk factor for numerous complications, including dislocation, infection, venous thromboembolism, component loosening, revision surgery, and medical complications. 13 , 14 Gupta et al conducted a retrospective review of primary RSAs with a minimum 90-day follow-up, including patients with a body mass index (BMI) exceeding 35 kg/m2, demonstrating these patients have a significantly higher overall medical and surgical complication rate (p <0.05) than patients with a BMI lesser than 35 kg/m2. 15
Infection: History and physical exam should be directed to identify any sign or symptom of infection, such as low-grade fever, warmth, erythema, open wounds, ulcers, or rashes. If, preoperatively, infection is a consideration in the differential diagnosis, a white blood cell count, C-reactive protein, and erythrocyte sedimentation rate should be obtained prior to surgery. Patients with an active infection remote to the shoulder, such as a urinary tract infection or chest infection, are absolutely contraindicated to an elective shoulder arthroplasty.
Smoking: A history of smoking/nicotine use has been suggested to be a risk factor for early revision after shoulder arthroplasty. 5 Furthermore, if we extrapolate from the hip and knee arthroplasty literature, it is very likely that smokers have a higher risk of postoperative complications, poor clinical outcomes, and early revision rates compared with nonsmokers following shoulder arthroplasty. 16 Whenever possible, smoking cessation strategies should be discussed with the patient preoperatively.
6.3 Physical Exam
The function of rotator cuff and deltoid should be verified with a thorough preoperative physical examination. External rotators should be carefully evaluated as previously described (hornblower sign, external rotation lag sign, and Patte test). Collin et al found that an external rotation lag sign greater than 40 degrees had better sensitivity and specificity than the other tests, with a sensitivity of 100% and a specificity of 92%. 17 Patients with an infraspinatus/teres minor tear and a positive external rotation lag sign may be indicated for concomitant latissimus dorsi and/or teres major transfer at the time of RSA to restore active external rotation. The functional status of the deltoid muscle can be verified sufficiently with manual muscle testing for effective contractility and strength. Electromyography may be used in rare circumstances to assess axillary nerve function preoperatively if there is a concern for axillary nerve dysfunction. Furthermore, it is usually possible to differentiate shoulder pathology with a comprehensive physical examination into four groups: motion, stability, strength, and smoothness. 18
6.3.1 Motion
Loss of ROM can occur in several different planes and should be differentiated in the following manner:
Active or passive.
Elevation, external and internal rotation, and abduction.
Initiation or terminal/end range.
Glenohumeral or scapulothoracic.
6.3.2 Stability
An assessment of glenohumeral stability is important. Understanding if the patient is able to maintain humeral head centering within the glenoid and maintain a stable fulcrum for elevation is crucial in order to determine the best treatment option. Posterior subluxation of the humeral head is common in osteoarthritic shoulders and can be associated with a biconcave glenoid and/or posterior glenoid bone deficiency. In elderly patients with anterosuperior (AS) instability and a massive rotator cuff tear or following hemiarthroplasty, RSA is an excellent surgical treatment option to allow a fixed fulcrum for effective elevation.
6.3.3 Strength
Appropriate evaluation of the strength of the rotator cuff, deltoid, and periscapular muscles must be done preoperatively. Patients with massive rotator cuff tears typically have impairment in initiation of elevation but are able to appropriately activate the deltoid muscle in midrange of motion. While deficiency or dehiscence of the deltoid muscle is not an absolute contraindication to RSA, Wiater et al have reported that larger preoperative deltoid size correlates with improved validated outcomes scores, whereas fatty infiltration of the deltoid, infraspinatus, and/or teres minor may have deleterious effects on outcomes scores and ROM after RSA. 19 In cases where there is concern for axillary nerve pathology, electromyography may be helpful to stage the degree of nerve injury.
6.3.4 Smoothness
Clicking, popping, and/or grinding associated with shoulder pain are common symptoms that suggest severe articular cartilage damage and/or arthrosis.
6.4 Imaging
Radiographs are a requisite for preoperative planning for RSA. There are four views recommended in the evaluation of a patient undergoing RSA: anteroposterior (AP) in external rotation, true AP in internal rotation (Grashey view), Y-lateral, and axillary. Using the true AP (Grashey) view, it is possible to evaluate the diameter of humeral head, acromiohumeral interval, and glenohumeral articular joint space. Several different radiological classifications for cuff tear arthropathy have been previously described with the Visotsky–Seebauer and Hamada classifications, showing improved reliability for evaluation of the humerus and glenoid. 20 Using the axillary view, it is possible to determine glenoid erosion, posterior subluxation, glenoid osteophytes, and the presence of an os acromiale.
A computed tomography scan is recommended when radiographs demonstrate signs of altered glenohumeral bony anatomy. Walch et al proposed a classification system based on the pattern of glenoid erosion and humeral head subluxation (► Table 6.1). 21 Additionally, bone loss related to cuff tear arthropathy has also been described. Glenoid bone stock is an important factor to take into account during surgical planning as it could help determine whether there may be the need for glenoid bone grafting at the time of RSA.
Related posts:
9 Debate: I Always Repair the Subscapularis Tendon If Possible versus the Subscapularis Tendon: A Vestigial Structure Following Reverse Total Shoulder Arthroplasty?
8 Indications and Techniques of BIO-RSA for Cuff Tear Arthropathy, Including Associated Soft Tissue Transfers for Loss of External Rotation
Chapter 10 Reverse Shoulder Arthroplasty for Acute Fracture: Indications and Technique
Chapter 11 Reverse Shoulder Arthroplasty for Fracture Sequelae: Indications and Technique
Chapter 15 Reverse Shoulder Arthroplasty in Revision Shoulder Arthroplasty: What I Look for and How I Do It
hapter 13 Reverse Shoulder Arthroplasty for Massive Anterosuperior Rotator Cuff Failure
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