Low posterior tibial slope is associated with increased risk of PCL graft failure.

PURPOSE: To evaluate the effect of posterior tibial slope (PTS) on patient-reported outcomes (PROs) and posterior cruciate ligament (PCL) graft failure after PCL reconstruction. METHODS: Patients undergoing PCL reconstruction with a minimum 2-year follow-up were included in this retrospective cohort study. A chart review was performed to collect patient-, injury-, and surgery-related data. Medial PTS was measured on preoperative lateral radiographs. Validated PROs, including the International Knee Documentation Committee Subjective Knee Form, Knee injury and Osteoarthritis Outcome Score, Lysholm Score, Tegner Activity Scale, and Visual Analogue Scale for pain, were collected at final follow-up. A correlation analysis was conducted to assess the relationship between PTS and PROs. A logistic regression model was performed to evaluate if PTS could predict PCL graft failure. RESULTS: Overall, 79 patients with a mean age of 28.6 ± 11.7 years and a mean follow-up of 5.7 ± 3.3 years were included. After a median time from injury of 4.0 months, isolated and combined PCL reconstruction was performed in 22 (28%) and 57 (72%) patients, respectively. There were no statistically significant differences in PROs and PTS between patients undergoing isolated and combined PCL reconstruction (non-significant [n.s.]). There were no significant correlations between PTS and PROs (n.s.). In total, 14 (18%) patients experienced PCL graft failure after a median time of 17.5 months following PCL reconstruction. Patients with PCL graft failure were found to have statistically significantly lower PTS than patients without graft failure (7.0 ± 2.3° vs. 9.2 ± 3.3°, p < 0.05), while no differences were found in PROs (n.s.). PTS was shown to be a significant predictor of PCL graft failure, with a 1.3-fold increase in the odds of graft failure for each one-degree reduction in PTS (p < 0.05). CONCLUSIONS: This study showed that PTS does not affect PROs after PCL reconstruction, but that PTS represents a surgically modifiable predictor of PCL graft failure. LEVEL OF EVIDENCE: III.

Cyclic loading induces anabolic gene expression in ACLs in a load-dependent and sex-specific manner.

Anterior cruciate ligament (ACL) injuries are historically thought to be a result of a single acute overload or traumatic event. However, recent studies suggest that ACL failure may be a consequence of fatigue damage. Additionally, the remodeling response of ACLs to fatigue loading is unknown. Therefore, the objective of this study was to investigate the remodeling response of ACLs to cyclic loading. Furthermore, given that women have an increased rate of ACL rupture, we investigated whether this remodeling response is sex specific. ACLs were harvested from male and female New Zealand white rabbits and cyclically loaded in a tensile bioreactor mimicking the full range of physiological loading (2, 4, and 8 MPa). Expression of markers for anabolic and catabolic tissue remodeling, as well as inflammatory cytokines, was quantified using quantitative reverse transcription polymerase chain reaction. We found that the expression of markers for tissue remodeling of the ACL is dependent on the magnitude of loading and is sex specific. Male ACLs activated an anabolic response to cyclic loading at 4 MPa but turned off remodeling at 8 MPa. These data support the hypothesis that noncontact ACL injury may be a consequence of failed tissue remodeling and inadequate repair of microtrauma resulting from elevated loading. Compared to males, female ACLs failed to increase anabolic gene expression with loading and exhibited higher expression of catabolic genes at all loading levels, which may explain the increased rate of ACL tears in women. Together, these data provide insight into load-induced ACL remodeling and potential causes of tissue rupture.

Diabetes Increases Median Nerve Cross-Sectional Area but Not Disease Severity in Patients with Carpal Tunnel Syndrome.

Background: Ultrasonography (US) is a useful diagnostic modality for diagnosis of carpal tunnel syndrome (CTS). Diabetes mellitus is increasingly prevalent and is a risk factor for CTS. Given the increasing use of US in the diagnosis of CTS, our goal was to evaluate the influence of diabetes on CTS severity and the cross-sectional area (CSA) of the median nerve in patients with CTS. Methods: Patients with clinically diagnosed CTS were seen in the outpatient setting from October 2014 to February 2021. Median nerve CSA and patient reported severity measures were obtained: Boston Carpal Tunnel Syndrome Questionnaire (BCTSQ) and CTS-6. For patients with diabetes, additional parameters were collected including most recent A1c, insulin pharmacotherapy, and polypharmacy. Results: Ninety-nine patients (122 nerves) without diabetes and 55 patients (82 nerves) with diabetes were recruited for the study. Patients in the diabetes group were more obese and older and had a significantly increased median nerve CSA compared with patients without diabetes. Obesity was associated with higher median nerve CSA in all patients but not in patients with diabetes. There was no difference in disease severity in patients with and without diabetes as reported by BCTSQ or CTS-6 scores. In patients with diabetes, there was significantly decreased median nerve CSA with A1c of 6.5 or higher and a trend to decreased CSA with polypharmacy. There was no influence of insulin therapy on median nerve CSA. Conclusion: Diabetes is associated with higher median nerve CSA in patients with CTS of similar disease severity. The increased median nerve CSA in patients with diabetes may be reflective of diabetes-related microvascular changes. Interestingly, the trend to decreased median nerve CSA in patients with suboptimal diabetic control (A1c ≥ 6.5) may suggest eventual degenerative changes to the median nerve. In summary, clinicians should be cautious with interpreting a larger median nerve CSA as more severe CTS in patients with diabetes. Level of Evidence: Level 3 Diagnostic.

Patients Prefer Ultrasound to Nerve Conduction Studies for the Diagnosis of Carpal Tunnel Syndrome.

Background: The net promoter score (NPS) allows analysis of patient satisfaction and preference between treatment and/or diagnostic testing. Electrodiagnostic testing (EDX) and ultrasound (US) are commonly used diagnostic tests for carpal tunnel syndrome. Although EDX is reliable for diagnosing carpal tunnel syndrome (CTS), it can be uncomfortable and inconvenient for patients. We aimed to determine whether patients preferred US or EDX studies for the diagnosis of CTS, using the NPS. Methods: Seventy-five patients presenting to the clinic for evaluation of CTS complaints who had EDX were prospectively studied. US evaluation of the median nerve was then completed at time of evaluation. Patient satisfaction was determined by asking, "how likely are you to recommend this procedure to a friend or relative?" for both EDX and US. Patient demographics, comorbidities, CTS-6 questionnaire (CTS-6), and functionality assessed through patient-reported qDASH were also recorded. Results: Sixty-five patients were included in the study. Most patients did not have any comorbidities and were nonsmokers. The gender composition was similar, and the average age of the enrolled patients was 58. The NPS for US was significantly higher than EDX (P < 0.0001). Patients with diabetes mellitus rated their EDX experience significantly lower than those without diabetes mellitus. Conclusions: Patients are more likely to recommend US instead of EDX in the evaluation of CTS complaints. This allows for shared decision-making between the patient and provider if ordering diagnostic testing for CTS.