Evaluating trunnionosis in modular anatomic shoulder arthroplasties: a retrieval study.

BACKGROUND: Shoulder arthroplasty procedures are widely indicated, and the number of shoulder arthroplasty procedures has drastically increased over the years. Rapid expansion of the utilization of reverse total shoulder arthroplasty has outpaced the more modest growth of anatomic total shoulder arthroplasty (aTSA) while shoulder hemiarthroplasty (HA) has trended down. Recently, shoulder prostheses have transitioned to increasingly modular systems offering more individualized options with the potential for decreased pain and increased range of motion. However, increased primary procedures has resulted in increased revision surgeries, with one potential cause being fretting and corrosion damage within these modular systems. METHODS: Following institutional review board approval, 130 retrieved aTSA and 135 HA explants were identified through database query. Humeral stem and head components were included in all 265 explants, whereas 108 included polyethylene glenoid liner components. All explanted components were macroscopically evaluated for standard damage modes, and taper junctions were microscopically examined for fretting/corrosion using a modified Goldberg-Cusick classification system that was 4-quadrant graded for both the male and female component. Medical records were reviewed for patient demographics and surgical information. RESULTS: In this series, 158 of explants were from female patients (male = 107), and 162 explants were from the right shoulder. Average age at implantation was 61 years (range: 24-83), average age at explanation was 66 years (range, 32-90), and average duration of implantation was 61.4 months (range, 0.5-240). Scratching, edge deformation, and burnishing were the most commonly observed standard damage modes. Of the 265 explants, 146 had a male stem component vs. 118 with a female stem component. Average summed fretting grades on male and female stem components were 8.3 and 5.9, respectively (P < .001). Average summed corrosion grades for male and female stem components were 8.2 and 6.2, respectively (P < .001). Wider male tapers (>11 mm) showed significantly less fretting and corrosion (P < .001). Lastly, mismatched metal compositions between the head and stem components showed greater fretting and corrosion damage (P = .002). CONCLUSION: In this series of 265 aTSA and HA explants, there was substantial damage present on the explanted components. All components demonstrated macroscopic damage. In this retrieval study, small-tapered male stems with small, thin female heads and mismatched metal composition between components were risk factors for increased implant wear. As shoulder arthroplasty volume increases, optimizing design is paramount for long-term success. Additional work could determine the clinical significance of these findings.

Larger-diameter trunnions and bolt-reinforced taper junctions are associated with less tribocorrosion in reverse total shoulder arthroplasty.

BACKGROUND: Morse taper junction tribocorrosion is recognized as an important failure mode in total hip arthroplasty. Although taper junctions are used in almost all shoulder arthroplasty systems currently available in the United States, with large variation in design, limited literature has described comparable analyses of taper damage in these implants. In this study, taper junction damage in retrieved reverse total shoulder arthroplasty (RTSA) implants was assessed and analyzed. METHODS: Fifty-seven retrieved RTSAs with paired baseplate and glenosphere components with Morse taper junctions were identified via database query; 19 of these also included paired humeral stems and trays or spacers with taper junctions. Components were graded for standard damage modes and for fretting and corrosion with a modified Goldberg-Cusick classification system. Medical records and preoperative radiographs were reviewed. Comparative analyses were performed assessing the impact of various implant, radiographic, and patient factors on taper damage. RESULTS: Standard damage modes were commonly found at the evaluated trunnion junctions, with scratching and edge deformation damage on 76% and 46% of all components, respectively. Fretting and corrosion damage was also common, observed on 86% and 72% of baseplates, respectively, and 23% and 40% of glenospheres, respectively. Baseplates showed greater moderate to severe (grade ≥ 3) fretting (43%) and corrosion (27%) damage than matched glenospheres (fretting, 9%; corrosion, 13%). Humeral stems showed moderate to severe fretting and corrosion on 28% and 30% of implants, respectively; matched humeral trays or spacers showed both less fretting (14%) and less corrosion (17%). On subgroup analysis, large-tapered implants had significantly lower summed fretting and corrosion grades than small-tapered implants (P < .001 for both) on glenospheres; paired baseplate corrosion grades were also significantly lower (P = .031) on large-tapered implants. Factorial analysis showed that bolt reinforcement of the taper junction was also associated with less fretting and corrosion damage on both baseplates and glenospheres. Summed fretting and corrosion grades on glenospheres with trunnions (male) were significantly greater than on glenospheres with bores (female) (P < .001 for both). CONCLUSIONS: Damage to the taper junction is commonly found in retrieved RTSAs and can occur after only months of being implanted. In this study, tribocorrosion predominantly occurred on the taper surface of the baseplate (vs. glenosphere) and on the humeral stem (vs. tray or spacer), which may relate to the flexural rigidity difference between the titanium and cobalt-chrome components. Bolt reinforcement and the use of large-diameter trunnions led to less tribocorrosion of the taper junction. The findings of this study provide evidence for the improved design of RTSA prostheses to decrease tribocorrosion.

National disparities in access to physical therapy after rotator cuff repair between patients with Medicaid vs. private health insurance.

BACKGROUND: Arthroscopic rotator cuff repair is an effective treatment for patients with symptomatic rotator cuff tears. Ensuring timely and appropriate postoperative access to physical therapy (PT) is paramount to the achievement of optimal patient outcomes. Extended immobility due to a lack of formal rehabilitation can lead to decreased range of motion, continued pain, and potential reoperation for stiffness. The purpose of this study is to evaluate national disparities in access to PT services after rotator cuff repair between patients with private vs. Medicaid insurance. This study will further evaluate differences in access to PT services between states that have previously undergone Medicaid expansion as compared with those states which have not. METHODS: The American Physical Therapy Association Website was used to identify 10 physical therapy practices from the capital city in every state. Each physical therapy practice was contacted using a mock-patient script for a patient with Medicaid insurance or private (Blue Cross Blue Shield) insurance. To maintain anonymity, calls were made by two separate investigators. Univariate analysis included independent sample t-test for differences between the study groups for continuous variables. Chi square or Fisher's exact test assessed differences in discrete variables between the study groups. RESULTS: Contact was made with 465 of 510 (91.2%) physical therapy practices. Overall, 52.7% accepted Medicaid insurance, while 94.9% accepted private insurance (P < .001). Medicaid insurance was more likely to be accepted in a Medicaid expansion state than a nonexpansion state (56.1% vs. 46.3%, P = .05). Private insurance was also more likely to be accepted in a Medicaid expansion state than a nonexpansion state (96.7% vs. 91.3%, P = .01). The time to first appointment varied more in Medicaid expansion states (private range: 0-43 days, Medicaid range: 0-72 days) than in nonexpansion states (private range: 0-11 days, medicaid range: 0-10 days). CONCLUSION: Significantly fewer PT practices accepted Medicaid insurance nationally compared with private insurance, which suggests that patients with Medicaid insurance have greater difficulty accessing PT after rotator cuff repair in the United States compared with patients with private insurance. While Medicaid insurance was more likely to be accepted in a Medicaid expansion state, this finding was only borderline significant, which indicates that patients in Medicaid expansion states are still having difficulty accessing PT, despite efforts to expand government insurance coverage to improve access to care. Orthopedic surgeons should counsel their patients with Medicaid insurance to seek out PT as early as possible in the postoperative period to avoid delays in rehabilitation.

Insurance status affects access to physical therapy following rotator cuff repair surgery: A comparison of privately insured and Medicaid patients.

Rotator cuff repair (RCR) is an effective procedure to relieve shoulder pain and dysfunction. Postoperative physical therapy (PT) plays an integral role in the overall success of RCR. Insurance status has been shown to be an important predictor of postoperative PT utilization. This study evaluated the effect of insurance status on access to PT services following RCR. One hundred thirty-eight PT clinics were contacted in the Greater Boston metropolitan area. Clinics were contacted on two separate occasions and presented with a fictitious acutely postoperative RCR patient in need of PT. Insurance status was reported as Medicaid or private insurance. Overall, 133 (96.4%) accepted private insurance, whereas only 71 (51.4%) accepted Medicaid (P=0.019). Medicaid patients were offered a first available appointment at a mean of 8.3 days (95% CI: 7.13-9.38, range: 0-31) versus a mean of 6.3 days (95% CI: 5.3-7.22, range: 0-19, P=0.001) for private patients. Clinic location was not associated with access to PT or time to first appointment. Insurance status affects access to PT services and time to first available appointment in patients following RCR surgery in a major metropolitan area.

Medicaid Health Insurance Status Limits Patient Accessibility to Rehabilitation Services Following ACL Reconstruction Surgery.

BACKGROUND: In the senior author's (X.L.) orthopaedic sports medicine clinic in the United States (US), patients appear to have difficulty finding physical therapy (PT) practices that accept Medicaid insurance for postoperative rehabilitation. PURPOSE: To determine access to PT services for privately insured patients versus those with Medicaid who underwent anterior cruciate ligament (ACL) reconstruction in the largest metropolitan area in the state of Massachusetts, which underwent Medicaid expansion as part of the Affordable Care Act. STUDY DESIGN: Cross-sectional study. METHODS: Locations offering PT services were identified through Google, Yelp, and Yellow Pages internet searches. Each practice was contacted and queried about health insurance type accepted (Medicaid [public] vs Blue Cross Blue Shield [private]) for postoperative ACL reconstruction rehabilitation. Additional data collection points included time to first appointment, reason for not accepting insurance, and ability to refer to a location accepting insurance type. Median income and percentage of households living in poverty were also noted through US Census data for the town in which the practice was located. RESULTS: Of the 157 PT locations identified, contact was made with 139 to achieve a response rate of 88.5%. Overall, 96.4% of practices took private insurance, while 51.8% accepted Medicaid. Among those locations that did not accept Medicaid, only 29% were able to refer to a clinic that would accept it. "No contract" was the most common reason why Medicaid was not accepted (39.4%). Average time to first appointment was 5.8 days for privately insured patients versus 8.4 days for Medicaid patients (P = .0001). There was no significant difference between clinic location (town median income or poverty level) and insurance type accepted. CONCLUSION: The study results reveal that 43% fewer PT clinics accept Medicaid as compared with private insurance for postoperative ACL reconstruction rehabilitation in a large metropolitan area. Furthermore, Medicaid patients must wait significantly longer for an initial appointment. Access to PT care is still limited despite the expansion of Medicaid insurance coverage to all patients in the state.