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Introduction. Expectations for limb length differences after TKA are important for patient perception and outcomes. Limb length discrepancies may occur due to postoperative leg length increases, which can lead to decreased patient functionality and satisfaction and even possible litigation. The purpose of this study is to examine the frequency and extent of limb lengthening among various preoperative deformities and between two different implant systems. Methods. Preoperative and postoperative full-length standing radiographs were obtained between August 2018 and August 2019 to measure mechanical axis and limb length of operative limbs. Demographic information such as age, sex, and BMI was also collected. Patients were grouped into categories for pre- and postoperative subgroup analysis: valgus, varus, customized implant, and conventional implant. Regression analysis was performed to evaluate significant relationships. Results. Of the 121 primary TKAs analyzed, 62% of the knees showed an increase in limb length after TKA, with an average lengthening of 5.32 mm. Preoperative varus alignment was associated with a mean lengthening of 3.14 mm, while preoperative valgus alignment was associated with a mean lengthening of 16.2 mm. Overall, there were no statistically significant differences in limb lengths pre- and postoperatively ( p  = 0.23) and no significant changes in limb length for any subgroup. Further, no variables were associated with limb length changes ( p  = 0.49), including the use of customized implants ( p  = 0.2). Conclusions. Limb lengthening after TKA is common and, on average, occurs more significantly in valgus knees. No significant difference in limb lengthening could be demonstrated using customized over conventional implants. Preoperative counseling is important to manage patient expectations.

We report a case of head-neck taper fretting corrosion in a patient who had a total hip replacement with a noncemented Stryker Anato femoral stem and a V40 metal head with a Stryker Tritanium hemispherical socket with a highly cross-linked polyethylene liner (metal on polyethylene) (Stryker, Mahwah, NJ, USA). A 57-year-old man presented with early-onset hip pain after right total hip arthroplasty. Workup was negative for infection. Metal artifact reduction sequence MRI revealed an encapsulated fluid mass. Metal ion cobalt level was elevated at 6 ppb. The patient underwent right revision total hip arthroplasty with excellent results at 1-year follow-up.

The purpose of the study was to evaluate the accuracy of a commercial automatic digital templating algorithm compared to manual digital templating in total knee arthroplasty (TKA). The study also evaluated if race and the presence of a standardized calibration marker on preoperative radiographs effect the accuracy of digital templating. One hundred twenty‐five consecutive patients undergoing primary TKA were included in the study. Patient demographics, etiology of arthritis, and the presence of a standardized calibration marker on preoperative anteroposterior (AP) and lateral radiographs was recorded. Manual digital templating and the use of the “auto‐knee” templating algorithm with “Traumacad” software was performed and recorded. Intraoperative sizes of the actual implants used were recorded. Pearson χ2 test was used to evaluate the accuracy of auto versus manual templating. Manual templating was within 1 size of the implant used intraoperatively for femoral and tibial implants 97.6% and 94.2% of the time, respectively. The “auto‐knee” algorithm was within one size of the implant used for femoral and tibial implants 51.2% and 71.2% of the time, respectively. The presence of a standardized calibration marker on the AP view did not change accuracy of templating for both components. There was no difference in accuracy of templating between races. We caution surgeons from exclusively using an automatic algorithm as it is less accurate than manual templating for TKA.

Debridement, antibiotics with implant retention (DAIR), and 2-stage revision are standard surgical interventions for treating knee periprosthetic joint infection (PJI). Patients with substance use disorder (SUD), especially addictive drug use disorder (DUD), have been shown to receive inferior medical care in many specialties compared with nonusers. The authors identified patients with a diagnosis of PJI after knee arthroplasty who received either DAIR or 2-stage revision with the Nationwide Inpatient Sample (NIS) database from 2010 to 2014. Patients were stratified into 2 groups, patients with DUD and nonusers, based on Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria. Descriptive analysis was conducted to show the national trend for knee PJI treatment among the 2 patient groups. Multivariate logistic regression was used to compare the prevalence of DAIR and 2-stage revision between these 2 groups, adjusted for likely confounders, including age, sex, income, race, and comorbidities. Among the 11,331 patients with knee infection, 139 (1.23%) had DUD. Compared with nonusers, patients with DUD were significantly younger ( P <.001), had more chronic conditions ( P <.001), and were predominantly in lower income quartiles ( P =.046). The 2 groups did not differ in sex and race ( P =.072 and P =.091, respectively). The authors found that 30.22% of patients with DUD and 36.36% of nonusers received DAIR. The difference in these proportions was not statistically significant ( P =.135). The results did not change after adjustment for confounding factors ( P =.509). The findings suggested that bias does not exist among orthopedic surgeons who choose DAIR or 2-stage revision for knee PJI among patients with DUD. [ Orthopedics . 2021;44(3):e385–e389.]