Primary Shoulder Hemiarthroplasty: What Can Be Learned From 359 Cases That Were Surgically Revised?

BACKGROUND: Primary shoulder hemiarthroplasty is used to address a range of glenohumeral disorders, including fracture, arthritis, avascular necrosis, and capsulorrhaphy arthropathy; some patients with hemiarthroplasties undergo revision surgery for persistent pain or residual shoulder dysfunction. The literature does not clarify the features of the hemiarthroplasties having repeat surgery in a way that can guide surgeons' efforts to minimize the need for revision. To help address this gap, we analyzed the characteristics of patients from our region for whom we performed surgical revision of a prior humeral hemiarthroplasty QUESTIONS/PURPOSES: (1) What are the common characteristics of shoulder hemiarthroplasties having a revision? (2) What are the common characteristics of the subset of revised shoulder hemiarthroplasties that were performed for fracture? (3) What are characteristics of the subset of all revised hemiarthroplasties that were associated with glenoid bone erosion? METHODS: Data for 983 patients for whom we performed a surgical revision of any type of shoulder arthroplasty between January 1991 and January 2017 were identified in our longitudinally maintained institutional arthroplasty revision database. In each case, revision had been elected by shared patient and surgeon decision-making after consideration of the disorder, degree of compromised comfort and function, treatment alternatives, and the risks of surgery. Of these 983 patients, 359 (37%) had a revision of a prior primary hemiarthroplasty; these patients were the subjects of this investigation. In this group of patients, we investigated the patient demographics, shoulder characteristics, prerevision radiographic findings, and findings at revision surgery. No patients were excluded. The patients having revision of primary hemiarthroplasties had severe loss of self-assessed shoulder comfort and function, with Simple Shoulder Test (SST) scores averaging 2.2 ± 2.2 of the maximum score of 12. The majority of these patients (81%) were women. The medical records of these 359 patients were abstracted to determine the diagnosis for the index primary hemiarthroplasty, clinical characteristics before surgery, and findings at surgical revision. One hundred twelve of the arthroplasties had been performed for fracture-related diagnoses; a subgroup analysis was performed on these patients. Two hundred seventy-three of the 359 patients (76%) had plain radiographs performed within 3 months before revision surgery that were adequate for assessing the radiographic characteristics of the glenoid, humerus, humeral component, and glenohumeral relationships; a subgroup analysis was performed on these patients. The degree of glenoid erosion was measured by a single observer in accordance with established criteria: Grade 1 is no erosion, Grade 2 is erosion limited to subchondral bone, Grade 3 is moderate erosion with medialization, and Grade 4 is medialization beyond the coracoid base. Some patients were included in both of these subgroups. RESULTS: Common characteristics of the revised hemiarthroplasties included female sex (81%), rotator cuff (89 of 359; 25%) or subscapularis (81 of 359; 23%) failure, problems related to prior fracture (154 of 359; 43%), glenoid erosion 125 of 359; 35%), and component malposition (89 of 359; 25%). Hemiarthroplasties performed for fracture-related problems often were associated with tuberosity malunion or nonunion (58 of 79; 73%) and decentering of the humeral component on the glenoid surface (45 of 71; 63%). Major erosion of the bony glenoid (Grade 3 or 4) was more common in decentered hemiarthroplasties (42 of 102; 41%) than for centered hemiarthroplasties (36 of 146; 25%) (Fisher's exact p = 0.008) and more common for hemiarthroplasties positioned in valgus (28 of 50; 56%) than for those positioned in neutral or varus (40 of 188; 21%) (Fishers' exact p < 0.0001). CONCLUSIONS: These findings suggest that some revisions of primary hemiarthroplasties may be avoided by surgical techniques directed at centering the prosthetic humeral articular surface on the glenoid concavity using proper humeral component positioning and soft tissue balance, by avoiding valgus positioning of the humeral component, and by managing glenoid disorders with a primary glenohumeral arthroplasty rather than a hemiarthroplasty alone. When durable security of the subscapularis, rotator cuff, and tuberosities is in question, the surgeon may consider a reverse total shoulder arthroplasty. LEVEL OF EVIDENCE: Level III, therapeutic study.

What can be learned from an analysis of 215 glenoid component failures?

BACKGROUND: Glenoid component failure is a prevalent mechanical complication of anatomic total shoulder arthroplasty. The objective of this study was to identify surgeon-controlled factors that may be addressed to reduce the rate of glenoid component failure that is sufficiently symptomatic to merit surgical revision. METHODS: We reviewed the clinical and radiographic features of 215 total shoulder arthroplasties that we revised for symptomatic glenoid component failure. RESULTS: Glenoid component failure was associated with poor patient self-assessed shoulder function (mean Simple Shoulder Test score, 3.0 ± 2.7). These shoulders often showed multiple failure modes; 72% had glenoid component loosening, 69% had polyethylene wear, 51% had glenohumeral decentering, and 25% had humeral component loosening. Metal-backed/hybrid and keeled glenoid designs had higher rates of loosening (P = .010), malposition (P = .007), dislocation (P < .001), and early failure (P = .044) in comparison to pegged designs. Glenoid components with cement on the backside were more prevalent among those revised sooner than 5 years after the index surgery (P < .001). CONCLUSIONS: Glenoid component failure remains a major cause of poor patient outcomes after total shoulder arthroplasty. The occurrence of severe glenoid component failure might be reduced by paying attention to glenoid component design and insertion technique, restoring the normal balance of the humeral head in the center of the glenoid, and considering a reverse total shoulder when the shoulder is unstable because of soft tissue deficiency.

Routine cultures for seemingly aseptic revision shoulder arthroplasty: are they necessary?

Propionibacterium acnes has recently gained attention as the leading cause of periprosthetic joint infections (PJIs) after shoulder arthroplasty. Unlike PJIs in the lower extremity, PJIs after shoulder arthroplasty usually have an indolent course and are notoriously difficult to diagnose. Most of the time, the diagnosis is made after positive intraoperative cultures are taken at the time of revision surgery. Adding even more complexity to the diagnosis is the high rate of P acnes-positive cultures taken at the time of primary shoulder surgery. In many cases the preoperative workup yields no suspicion for infection; however, intraoperative cultures are taken to completely eliminate the potential of an ongoing indolent infection. Concerns over how to interpret positive P acnes culture results and the high rate of culture positivity in primary shoulder arthroplasty, as well as the potentially high rate of contamination, have led surgeons to wonder about the utility of obtaining intraoperative cultures at the time of revision shoulder arthroplasty. We present evidence for and against the practice of obtaining routine intraoperative cultures at the time of seemingly aseptic revision shoulder arthroplasty.

Infection Prevention in Shoulder Surgery.

The microbiome of the shoulder demonstrates distinctive differences to other orthopaedic surgical sites. Recent studies have demonstrated that the most common organisms found in deep shoulder infections are coagulase-negative staph lococcal species and Propionibacterium acnes . Many studies support diligent hand washing, decreasing operative time, routine glove changing, minimizing operating room traffic, and covering instruments as means for decreasing the risk of deep infection. On the other hand, hair clipping and the use of adhesive drapes may have little effect on decreasing the incidence of deep infection. Although generally considered the most efficacious skin preparation solution, chlorhexidine gluconate has minimal effect on eradication of P. acnes from the surgical site; however, the addition of preoperative topical applications of benzoyl peroxide to standard surgical preparation has shown promise in decreasing the rate of P . acnes culture positivity. Additionally, the use of local antibiotic formulations seems to be an effective means of preventing deep infection.

The economic significance of orthopaedic infections.

Musculoskeletal infections are a leading cause of patient morbidity and rising healthcare expenditures. The incidence of musculoskeletal infections, including soft-tissue infections, periprosthetic joint infection, and osteomyelitis, is increasing. Cases involving both drug-resistant bacterial strains and periprosthetic joint infection in total hip and total knee arthroplasty are particularly costly and represent a growing economic burden for the American healthcare system. With the institution of the Affordable Care Act, there has been an increasing drive in the United States toward rewarding healthcare organizations for their quality of care, bundling episodes of care, and capitating approaches to managing populations. In current reimbursement models, complications following the index event, including infection, are not typically reimbursed, placing the burden of caring for infections on the physician, hospital, or accountable care organization. Without the ability to risk-stratify patient outcomes based on patient comorbidities that are associated with a higher incidence of musculoskeletal infection, healthcare organizations are disincentivized to care for moderate- to high-risk patients. Reducing the cost of treating musculoskeletal infection also depends on incentivizing innovations in infection prevention.

Evaluation and treatment of the infected shoulder arthroplasty.

Infection after shoulder arthroplasty remains one of the most common postoperative complications. Treatment options range from debridement, appropriate antibiotic regimen, and retaining the implant to resection arthroplasty in the elderly medically challenged patient. We review the diagnostic challenges and treatment options for periprosthetic infections involving the shoulder. It appears that early detection, isolation of the infecting organism, and aggressive debridement with appropriate antibiotic treatment is the most important component of a successful treatment program designed to eradicate the infection. This early treatment which in most cases is combined with a two-stage approach (with an interim antibiotic spacer) provides the best opportunity to obtain a reasonably painless and functional shoulder arthroplasty.

Enzyme-linked immunosorbent assay for measurement of cytomegalovirus glycoprotein B antibody in serum.

Measurement of antibody to cytomegalovirus (CMV) glycoprotein B (gB) is valuable in the assessment of the antibody response to infection and to gB-containing vaccines. For this purpose, an enzyme-linked immunosorbent assay (ELISA) with a recombinant CMV gB molecule as the antigen was evaluated. Sera from 168 anti-CMV IgG-positive and 100 seronegative subjects were used to evaluate the anti-gB antibody assay. A cutoff optical density (OD) that would distinguish gB antibody-positive from -negative sera was established. Titers of antibody to gB determined by endpoint dilution were compared with those calculated using regression analysis. The run-to-run and interoperator reproducibilities of results were measured. The mean OD + 5 standard deviations from 50 anti-CMV IgG antibody-negative sera (0.2472) was used as the cutoff between anti-gB antibody-positive and -negative results. All sera from 100 anti-CMV IgG-seronegative subjects were negative for antibody to gB. All but 1 of 168 sera from seropositive subjects were positive for antibody to gB. Observed antibody levels based on titration to the endpoint were very similar to results calculated using linear regression. The run-to-run consistency of endpoints was excellent, with 38 runs from one operator and 48 runs from another all giving results within 1 dilution of the mean value for each of three anti-CMV IgG antibody-positive serum pools. The geometric mean titer of antibody to gB for 99 sera from seropositive blood donors was 1/10,937. This ELISA gives accurate and reproducible results for the relative quantity of anti-CMV gB IgG in serum over a wide range of antibody levels.