Purpose: The impact of altering a patient’s hip offset during total hip arthroplasty (THA) on periprosthetic fracture risk is unknown. The purpose of this study was to compare periprosthetic fracture risk in patients where THA offset was “matched” to their contralateral native hip versus those where offset was mismatched. Materials and Methods: We reviewed 50 patients with Vancouver B periprosthetic fractures at a single academic institution between 2012 and 2019 and compared them with a matched cohort. By utilizing a validated technique, two reviewers calculated combined hip offset from anteroposterior pelvis radiographs. Offsets of the operative side and the native hip were measured and denoted as either as a “match” if values were within 5 mm of the contralateral, native hip, or a “mismatch” if the prosthetic horizontal hip offset differed more than 5 mm from the native side. Independent sample t-tests and chi square analyses were used for data comparison. Relative risk (RR) with a 95% confidence interval (CI) was then calculated. Results: Unmatched offset was associated with increased risk of periprosthetic fracture (P<0.001). This finding was true for cases where offset was increased relative to the native hip (P<0.001) and where implant offset was decreased relative to the native hip (RR=3.0, 95% CI 1.3-7.6, P=0.015). Conclusion Failure to restore a patient’s offset during THA is associated with increased rates of periprosthetic fracture. Although restoration of native hip anatomy is an important technical consideration of this procedure, alterations in the hip lever arm may predispose patients to periprosthetic fracture.

Background: Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Conventional cruciate-retaining (CR) design in TKA has shown previous clinical success with lower complication rates. This study compared the patient-reported outcomes between the BCS and CR TKA designs. Methods: This retrospective study examined patients who underwent primary TKA using a CR or a BCS implant. Patient demographics, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR), and Forgotten Joint Score (FJS) were compared between two cohorts. Patient-reported outcome measures were analyzed using independent samples t-tests. Results: There were no significant preoperative demographic differences between groups. The CR cohort (n = 756) had significantly higher average KOOS, JR Scores compared to the BCS cohort (n = 652) at 3 months (59.7 ± 3.8 vs. 53.0 ± 3.9, p < 0.001) and 2 years (62.6 ± 8.0 vs. 53.8 ± 6.7, p = 0.001) after TKA. Within the cohort, KOOS, JR delta differences were not significant for CR when comparing patient scores 3 months to 1 year after surgery. Meanwhile, the BCS patients did show significant delta improvement (4.1 ± 1.9, p = 0.030) when compared 3 months to 1 year after surgery. One year postoperatively, the BCS cohort (n = 134) showed a significantly higher average FJS score (49.5 ± 31.4, vs. 36.8 ± 28.5, p = 0.028) than the CR cohort (n = 203). Both cohorts displayed a significant difference in delta improvements within their respective cohort when measuring FJS from 3 months to 1 year, 2 years, and 3 years after surgery. Conclusions The CR cohort performed better on average, compared to the BCS cohort in measures of KOOS, JR scores at the 2-year follow-up. The BCS cohort performed marginally better regarding FJS only at 1-year follow-up.