With an annual incidence of 68.6 per 100,000 person-years, isolated ACL tears remain a common orthopaedic injury. Differences in age-specific incidence trends in male and female patients may potentially reflect differences in sports participation patterns through the high school and college years. The significant increase in the rate of ACL reconstruction over time may reflect changing surgical indications or an increasing desire among patients to return to high levels of activity after ACL injury.

Background Lateral elbow tendinosis (epicondylitis) is a common condition both in primary care and specialty clinics. Purpose To evaluate the natural history (ie, incidence, recurrence, and progression to surgery) of lateral elbow tendinosis in a large population. Study Design Descriptive epidemiology study. Methods The study population comprised a population-based incidence cohort of patients with new-onset lateral elbow tendinosis between January 1, 2000, and December 31, 2012. The medical records of a 10% random sample (n = 576) were reviewed to ascertain information on patient and disease characteristics, treatment modalities, recurrence, and progression to surgery. Age- and sex-specific incidence rates were calculated and adjusted to the 2010 US population. Results The age- and sex-adjusted annual incidence of lateral elbow tendinosis decreased significantly over time from 4.5 per 1000 people in 2000 to 2.4 per 1000 in 2012 (P <.001). The recurrence rate within 2 years was 8.5% and remained constant over time. The proportion of surgically treated cases within 2 years of diagnosis tripled over time, from 1.1% during the 2000–2002 time period to 3.2% after 2009 (P <.00001). About 1 in 10 patients with persistent symptoms at 6 months required surgery. Conclusion The decrease in incidence of lateral elbow tendinosis may represent changes in diagnosis patterns or a true decrease in disease incidence. Natural history data can be used to help guide patients and providers in determining the most appropriate course at a given time in the disease process. The study data suggest that patients without resolution after 6 months of onset may have a prolonged disease course and may need surgical intervention.

Patients treated with ACLR have a significantly lower risk of secondary meniscal tears, symptomatic arthritis, and TKA when compared with patients treated nonoperatively after ACL tears. Similarly, early ACLR significantly reduces the risk of subsequent meniscal tears and arthritis compared with delayed ACLR.

Purpose Arthrofibrosis is a rare complication after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to (1) report a population‐based incidence of arthrofibrosis (as defined by manipulation under anaesthesia or surgical lysis of adhesions) following ACL injury and reconstruction, (2) identify risk factors associated with development of arthrofibrosis, and (3) report outcomes of intervention for arthrofibrosis. Methods This was a historical cohort study performed in Olmsted County, Minnesota. The Rochester Epidemiology Project (REP) was used to identify a population‐based cohort of individuals with new‐onset, isolated ACL tears between 1 January 1990 and 31 December 2010. The REP database provides access to all medical records for each resident of Olmsted County, regardless of the facility where the care was delivered. A total of 1841 individuals were identified with new‐onset, isolated ACL tears and were confirmed with chart review. The intervention incidence for arthrofibrosis was then calculated, and various predictive factors including age, sex, calendar year, and meniscal injury were investigated. Results During follow‐up, 5 patients (1.0 %) in the non‐operative cohort and 23 patients (1.7 %) in the ACL reconstruction cohort received intervention for arthrofibrosis, corresponding to an incidence of 0.7 per 1000 person‐years in the non‐operative cohort and 1.9 per 1000 person‐years in the ACL reconstruction cohort. Female patients were 2.5 times more likely to have arthrofibrosis than males. The mean preoperative range of motion was −8° to 83° and improved to a mean of −2° to 127° post‐operatively. Conclusions Arthrofibrosis remains a rare but potentially devastating complication after ACL reconstruction, and roughly 2 % of patients had post‐operative stiffness that required intervention. Female patients are at higher risk of arthrofibrosis. However, when patients develop severe motion complications after ACL injury, interventions are generally effective in preventing permanent arthrofibrosis.

Retrospective comparative study, Level III.