Decreased Patellar Fractures and Subluxation With Patellar Component Replacement at Stage-One Spacer.

BACKGROUND: Periprosthetic joint infection is a devastating complication of total knee arthroplasty and is often treated with 2-stage revision. We retrospectively assessed whether replacing the patellar component with articulating stage-one spacers was associated with improved outcomes compared to spacers without patellar component replacement. METHODS: A total of 139 patients from a single academic institution were identified who underwent an articulating stage-one revision total knee arthroplasty and had at least 1-year follow-up. Of the 139 patients, 91 underwent patellar component removal without replacement, while 48 had a patellar component replaced at stage-one revision. Patellar fracture and reinfection at any point after stage-one were recorded. Knee range of motion (ROM), patellar thickness, lateral tilt, and lateral displacement were measured at 6-weeks post stage-one. Chi-square, Fisher's exact, and t-tests were utilized for comparisons. There were no significant demographic differences between groups. RESULTS: Patellar component replacement at stage-one revision was associated with fewer patellar fractures (2.1 versus 12.1%, P = .046), less lateral patellar displacement (1.7 versus 16.0 mm, P < .01), and improved pre to postoperative knee ROM 6 weeks after stage-one (+5.9 versus -11.4°, P = .03). There was no difference in reinfections after stage-2 revision for the replaced or unreplaced patellar groups (15.4 versus 15%, P = 1.000). While the mean time between stage-one and stage-2 was not different (5.2 versus 4.5 months, P = .50), at one-year follow-up, significantly more patients in the patellar component replacement group were satisfied and refused stage-2 revision (45.8 versus 3.3%, P < .001). CONCLUSIONS: Replacing the patellar component at stage-one revision is associated with a decreased rate of patellar fracture and lateral patellar subluxation, improved ROM, and possible increased patient satisfaction, as reflected by nearly half of these patients electing to keep their spacer. There was no difference in reinfection rates between the cohorts.

Metallosis and Corrosion Associated With Revision Total Knee Arthroplasties With Metaphyseal Sleeves.

Metallosis and corrosion have been associated with metal-on-metal and modular total hip arthroplasty but are rarely described in the setting of primary or revision total knee arthroplasty (TKA). In this series, we report on cases of metallosis due to mechanically assisted crevice corrosion at modular junctions of machined trunnion-bore tapers in a revision TKA system with metaphyseal sleeves. The unique design of metal modular junctions used in sleeve-based revision TKA, along with potential patient and surgical factors, may predispose these designs to fretting, corrosion, and adverse reaction to metal debris. We now consider metallosis and corrosion in the workup of painful or failed revision TKAs with sleeves. Future studies that investigate the incidence of this phenomenon may be warranted.

Displaced Versus Nondisplaced Femoral Neck Fractures: Is Arthroplasty the Answer for Both?

BACKGROUND: Traditionally, nondisplaced geriatric femoral neck fractures (FNFs) have undergone operative fixation, while displaced geriatric FNFs have undergone hip arthroplasty. The purpose of this study was to evaluate differences between outcomes in patients with nondisplaced (Garden I and II) fractures and displaced (Garden III and IV) fractures that were treated with arthroplasty. METHODS: This was a retrospective review of patients who had a minimum of 1 year follow-up from nine academic medical centers who underwent arthroplasty for FNFs between 2010 and 2020. Chi-square, Fisher's Exact, and t-tests were used to compare demographics and outcomes between patients who had a displaced fracture and those who had a nondisplaced fracture. We included 1,620 patients, with 131 in the nondisplaced cohort and 1,497 in the displaced cohort. The mean follow-up in the study was 26.4 months. Both groups were similar in terms of demographic variables. RESULTS: At 1-year follow-up, the overall reoperation rate was 7% and was not different between patients who had nondisplaced compared to displaced FNFs who underwent arthroplasty. Heterotopic ossification (HO) was significantly higher in displaced (23.6%) versus nondisplaced fractures (11.7%) (P = .0021). Operative times and blood loss were higher in nondisplaced than displaced fractures that underwent arthroplasty. CONCLUSION: Hip arthroplasty is an excellent treatment option for nondisplaced and displaced geriatric FNFs with relatively low and similar reoperation rates at 1 year. Compared to previously published reoperation rates of internal fixation of nondisplaced FNFs, hip arthroplasty is a reasonable treatment option for nondisplaced FNFs to potentially decrease reoperations in a frail patient population.