The role of relaxin in anterior cruciate ligament injuries: a systematic review.

OBJECTIVE: Anterior cruciate ligament (ACL) tears are exceedingly common among the athletic population and are seen with higher incidence in females. Observational studies have noted peak ACL tear rates in the luteal phase of the menstrual cycle, a time in which the hormone relaxin peaks in serum concentration. METHODS: A systematic review of the literature was performed. Inclusion criteria specified all prospective and retrospective studies which included the role of relaxin in the pathogenesis of ACL tears. RESULTS: Six studies met inclusion criteria yielding 189 subjects from clinical studies and 51 in vitro samples. Included studies found that ACL samples exhibit selective relaxin binding. When pre-treated with estrogen prior to relaxin exposure, female ACL tissue samples exhibit increased expression of collagen degrading receptors. CONCLUSION: Relaxin displays binding specificity to the female ACL and increased serum concentrations are correlated with increased ACL tear rates in female athletes. Further research is needed in this area. LEVEL OF EVIDENCE: V.

Revision total knee arthroplasty for arthrofibrosis improves range of motion.

PURPOSE: Arthrofibrosis after primary total knee arthroplasty (TKA) is a significant contributor to patient dissatisfaction. While treatment algorithms involve early physical therapy and manipulation under anaesthesia (MUA), some patients ultimately require revision TKA. It is unclear whether revision TKA can consistently improve these patient's range of motion (ROM). The purpose of this study was to evaluate ROM when revision TKA was performed for arthrofibrosis. METHODS: A retrospective study of 42 TKA's diagnosed with arthrofibrosis from 2013 to 2019 at a single institution with a minimum 2-year follow-up was performed. The primary outcome was ROM (flexion, extension, and total arc of motion) before and after revision TKA, and secondary outcomes included patient reported outcomes information system (PROMIS) scores. Categorical data were compared using chi-squared analysis, and paired samples t tests were performed to compare ROM at three different times: pre-primary TKA, pre-revision TKA, and post-revision TKA. A multivariable linear regression analysis was performed to assess for effect modification on total ROM. RESULTS: The patient's pre-revision mean flexion was 85.6 degrees, and mean extension was 10.1 degrees. At the time of the revision, the mean age of the cohort was 64.7 years, the average body mass index (BMI) was 29.8, and 62% were female. At a mean follow-up of 4.5 years, revision TKA significantly improved terminal flexion by 18.4 degrees (p < 0.001), terminal extension by 6.8 degrees (p = 0.007), and total arc of motion by 25.2 degrees (p < 0.001). The final ROM after revision TKA was not significantly different from the patient's pre-primary TKA ROM (p = 0.759). PROMIS physical function, depression, and pain interference scores were 39 (SD = 7.72), 49 (SD = 8.39), and 62 (SD = 7.25), respectively. CONCLUSION: Revision TKA for arthrofibrosis significantly improved ROM at a mean follow-up of 4.5 years with over 25 degrees of improvement in the total arc of motion, resulting in final ROM similar to pre-primary TKA ROM. PROMIS physical function and pain scores showed moderate dysfunction, while depression scores were within normal limits. While physical therapy and MUA remain the gold standard for the early treatment of stiffness after TKA, revision TKA can improve ROM. LEVEL OF EVIDENCE: IV.

Return to Recreational Sport Following Lumbar Fusion.

STUDY DESIGN: This was a retrospective questionnaire study at a single academic medical center. OBJECTIVE: The objective of this study was to obtain information on rates of return to sport following lumbar fusion as well as sport-specific effects to improve evidence-based preoperative patient counseling. SUMMARY OF BACKGROUND DATA: Lumbar spinal fusion is one of the fastest-growing surgical procedures, with the majority being in patients aged 60 years and older. Remaining active is an important consideration for elderly patients undergoing lumbar spinal fusion. Golf, swimming, and biking are common forms of recreational exercise for an older population in whom lumbar fusion is often performed. There is a lack of data in the current literature regarding rates of return to recreational sporting activities following elective lumbar fusion. METHODS: Following Institutional Review Board approval, all patients undergoing lumbar fusion at a single institution from 2012 to 2016 were screened and included in this study. A minimum of 1-year postoperative follow-up was required. A total of 117 patients were identified undergoing single-level or multilevel lumbar fusion during this time period. The average age was 63 years. Questionnaires were obtained to screen and identify patients who participated in 1 of 3 recreational sports before surgery (golf, swimming, and biking). Preoperative and postoperative collected outcome measures were then compared using the Student t test. RESULTS: Of the 117 identified lumbar fusion patients, 32 patients (27%) participated in 1 of the 3 most common recreational sporting activities of golf, swimming, or biking. Within the golf cohort (n=13), 100% of patients returned to recreational golfing postoperatively. There was a statistically significant reduction in Visual Analog Scale (VAS) pain scores postoperatively (6.3±3.7-1.8±2.4, P=0.01). Driving distance was reduced postoperatively (223.3±42.7-212.1±44.4 yards, P=0.042) and handicaps increased (12.8±8.4-17.0±11.4, P=0.02). Within the swimming cohort (n=9), 100% of patients returned to recreational swimming following lumbar fusion. There was a statistically significant reduction in VAS pain scores postoperatively (9.1±1.7-2.2±2.3, P=0.01). There was a trend towards increased amounts of swimming (times per week) postoperatively, however, this was not statistically significant (2.1±1.7-3.7±1.5, P=0.10). Within the biking cohort (n=10), 100% of patients returned to recreational biking following lumbar fusion. There was a statistically significant reduction in VAS pain scores postoperatively (6.7±4.0-1.3±1.7, P=0.03). There was a trend towards increased amounts of biking (times per week) postoperatively, however, this was not statistically significant (2.5±1.8-3.7±1.6 postoperatively, P=0.20). CONCLUSIONS: In the cohort of patients from this study who partook in golfing, swimming or bicycling, 100% were able to return to their respective sport by 3-9 months postoperatively and all had a significant reduction in pain. With regards to golfers, lumbar fusion likely has an adverse effect on their golfing ability with an increase in handicap and an expected reduction in driving distance.