Reconstruction of the Anterior Cruciate Ligament(ACL-R) in the 30+-Year Old Assessed by Patient Reported Outcome Measures(PRO) Using the Nationwide Danish Knee Ligament Reconstruction Registry

Quality Assurance Plan: Clinical data reported by orthopedic surgeons at public and private hospitals, while patients undergoing ACL-R report PRO.

Source Data Verification with the Danish National Central Person Registry. Degree of completeness compared to Central Person Registry is approximately 85%.

Data dictionary provided by the data manager at RKKP - "Regionernes Kliniske Kvalitetudviklingsprogram" - Regional Clinical Quality Development Program. Patients are recruited when the ACL-R is performed, and approximately 35% report PRO 1 year after surgery. Data collection, data management and the extract from the Danish Knee Ligament Reconstruction Registry is performed by the Regional Clinical Quality Development Program. Data analysis done with support from statistician from "Region Sjælland" - Region Zealand. Sample Size Assessment not done. The cohort size is the largest we can get from the registry. The estimated number of patients 30 years of age or older with complete PROs is 2,600 men and 1,600 women. This estimation is based on the numbers from the annual report of 2019 from the Danish Knee Ligament Reconstruction Register, which states that 7,368 men and 4,656 women 30 years of age or older has undergone the procedure from 2005-2018. We expect that they report PROs as frequently as the entire cohort, which is approximately 35%. Patients with missing data will be described in table 3 and not used in table 2.

The study will present five tables.

Flowchart: Cohort size, excluded patients, patients with missing values, patients in each age group

Table 1: Descriptive statistics of the cohort with reported PRO stratified in three strata (0-14 years of age, 15-29 years of age or 30 years of age or older) with information about gender, age, previous surgery in the knee, activity at time of injury, operational technique and cartilage and meniscal status.

Table 2: Unpaired t-test if data shows normal distribution, otherwise Mann-Whitney, by change in KOOS from before surgery to one year after surgery, overall KOOS one year after surgery, Tegner one year after surgery, and Tegner from preoperatively to one year after surgery

Table 3: Descriptive statistics of population lost during follow-up

Table 4: Multivariate analysis for primary outcome

Sampling Method: Consecutive patients. Patients are enrolled into the registry when the ACL-R is performed. The completeness of registry depends on physicians' reporting of pre-, intra- and postoperative findings and patients' reporting of PROs.