Shoulder Pain Management

Advances in Joint Replacement

There have been advances in shoulder implant design and surgical techniques which have significantly improved treatment options for patients with chronic shoulder pain. These advances have the potential to change surgical treatment choices, making surgical intervention a more viable option for patients with chronic shoulder pain. Today’s surgical benefits may include:

• Less pain
• Shorter recovery time
• Minimized risk of mechanical failure

Advances in Surgical Techniques

Technologically Advanced Materials

The introduction of cobalt-chrome and titanium alloys inaugurated a new era of prostheses capable of meeting the biomechanical demands of total hip, knee and shoulder arthroplasty. Mechanical failure of these biocompatible metals is rare,¹ a fact that has expanded the pool of patients who might benefit from total joint arthroplasty.

Medical-grade polyethylene is an advancement specifically formulated to significantly decrease wear and osteolytic potential in the shoulder,^2,3 thereby reducing glenoid loosening, the most common complication of shoulder surgery.⁴ Scientifically advanced cross-linked polyethylene has demonstrated an 85% reduction in wear debris^2,3 over conventionally manufactured and sterilized components, and has significantly lowered the risk of aseptic loosening.

Enhanced Fixation

The use of press-fit humeral stems and porous coating allow for immediate fixation and long-term biological tissue in-growth. Recent advancements in this area include the availability of hydroxyapatite to encourage quicker  biological tissue in-growth. Long-term stability relies on bony integration, which increases fixation strength.⁵

Orthopaedic implants are secured in one of two ways, either with bone cement or by natural tissue growth. When a patient’s existing bone stock is appropriate, new surgical techniques and implants allow for cementless implantation and use the patient’s natural tissue growth for fixation. A sandpaper-like porous implant coating allows the patient’s tissue to naturally grow onto the implant; this is called biological tissue in-growth or biological fixation.

Cementless humeral resurfacing presents a bone-conserving option for patients with glenohumeral arthritis. A series of patients younger than age 55 were followed for 2 years after humeral resurfacing.⁶

• Pain scores measured by a visual analog scale improved significantly (P<0.001).
• The American Shoulder and Elbow Surgeons (ASES) scale also improved significantly (P<0.001).
• No radiographic evidence of loosening was seen.
• 97% of patients were satisfied with their outcome and had returned to desired activities.

Bone-Sparing Options

Newer implant designs, compared to legacy shoulder implants, conserve bone by minimizing the size of the humeral implant or utilizing new philosophies, such as resurfacing only the humeral head. For patients with active lifestyles that suffer from mild to moderate osteoarthritis, resurfacing preserves as much healthy bone and tissue as possible.

Implants Designed to Restore Complex Biomechanics

The shoulder is the most mobile joint in the body, but also one of the most complex. With the humeral head approximately twice the size of the glenohumeral surface, the joint possesses great flexibility as long as the surrounding soft tissues remain intact and healthy. When reconstruction is required, a full array of implants for shoulder surgery, from resurfacing to hemi, total and reverse arthroplasty, are available to the surgeon. Each design acknowledges the complex biomechanics of the shoulder with the aim of reducing pain and improving function. Additionally, the wide size selection exists to offer the surgeon a choice of implants necessary to reestablish natural shoulder kinematics without compromising the joint.⁷

Reverse shoulder arthroplasty is the latest procedure for patients who have lost mechanical function of the rotator cuff and all other treatment options have failed. Prior to reverse arthroplasty, patients with this condition had to cope with long-term pain and disability. The procedure restores the complex biomechanics of the shoulder by literally reversing the anatomical structure of the joint. The deltoid muscle is then used to bear the physical demands placed upon the rotator cuff.

Patient Studies

In one study, investigators performed a retrospective analysis of 994 total shoulder, 15,414 total hip, and 34,471 total knee cases entered into the Maryland Health Services Cost Review Commission during a 7-year period (1994-2001).⁸ The primary diagnosis was osteoarthritis, but secondary ICD9 codes were examined to determine co-morbidities. They found:

• No significant difference in mortality for total shoulder arthroplasty (0%) compared with total knee arthroplasty (0.16%) or total hip arthroplasty (0.18%).
• Significantly fewer complications (7.55%) for total shoulder arthroplasty (TSA) than total knee arthroplasty (14.7%) or total hip arthroplasty (15.5%) patients. Patients who had TSA were only half as likely to have at least one complication as total knee arthroplasty or total hip arthroplasty patients.
• Lower hospital charges ($10,351) for total shoulder arthroplasty than total knee arthroplasty ($14, 674) or total hip arthroplasty ($15,422) patients, even after adjusting for co-morbidities.
• Shorter length of stay for total shoulder arthroplasty (2.42 days) than for total knee arthroplasty (4.31 days) or total hip arthroplasty (4.37 days) patients.

The author states that 98% of patients reported feeling relief after shoulder arthroplasty.⁸

Outcome studies have reported high levels of patient improvement following the procedure. In a prospective study of 125 patients (ages 32-80) with chronic full-thickness rotator cuff tear, researchers reported that there were substantial improvements in outcomes, with significant improvements recorded in physical function [p=0.02], role physical [p<0.001], bodily pain [p=0.001], vitality [p=0.04], social function [p=0.02], and role emotional [p=0.03].⁹ Only mental health [p=.17] and general health [p=.78] did not improve significantly. This study demonstrated that patients with multiple medical co-morbidities had a greater improvement in scores for shoulder pain, function, and quality of life than those with less co-morbidity.

In another prospective, randomized, double-blind clinical trial of 41 patients (ages 61-79) with osteoarthritis of the shoulder, researchers looked at the outcome difference in patients who underwent arthroplasty versus hemiarthroplasty.¹⁰ The study showed that total shoulder arthroplasty and hemiarthroplasty resulted in significant improvements in quality of life in all domains of health, with a 3-fold post surgical improvement in quality of life domains of physical symptoms, sports/recreation/work and lifestyle.

Finally, postoperative results from a study of 299 patients (ages 29-94) treated for glenohumeral joint disease (rheumatoid arthritis, capsulorrhaphy arthropathy, and primary and secondary osteoarthritis) with total shoulder arthroplasty, reported significant improvement in comfort and function.¹¹ The magnitude of this improvement, as well as the profile of gains in the individual categories of comfort, motion, strength, and ability, differed according to the presenting diagnosis.

References