Major Increase in Incidence of Pediatric ACL Reconstructions From 2005 to 2021: A Study From the Norwegian Knee Ligament Register

Abstract

Background: The incidence of pediatric and adolescent anterior cruciate ligament reconstruction (ACLR) is increasing in several countries. It is uncertain whether this trend applies to countries that traditionally prefer an initial nonoperative treatment approach whenever possible, like Norway. Nationwide, long-term patient-reported outcomes and revision rates after ACLR in the pediatric population are also lacking.

Purpose: To determine the incidence of pediatric ACLR in Norway since 2005, as well as to detect trends in surgical details and describe patient-reported outcomes up to 10 years after ACLR.

Study design: Descriptive cohort study.

Methods: This study is based on prospectively collected data on girls ≤14 years and boys ≤16 years, registered in the Norwegian Knee Ligament Register at the time of their primary ACLR, between 2005 and 2021. The main outcome was the incidence of ACLR, adjusted to the corresponding population numbers for each year. The time trend was analyzed by comparing the mean of the first and last 3-year period (2005-2007 and 2019-2021). Patient-reported outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score preoperatively and at 2, 5, and 10 years postoperatively.

Results: A total of 1476 patients (1484 cases) were included, with a mean follow-up of 8.1 years (range, 1-17). The incidence of pediatric ACLRs per 100,000 population increased from 18 to 26, which corresponds to an increase of 40% for boys and 55% for girls. Concurrent meniscal procedures increased significantly from 45% to 62%, and the proportion of meniscal repairs increased from 19% to 43% when comparing the first and last time period. The mean Knee injury and Osteoarthritis Outcome Score values for the Sport and Recreation and Quality of Life subscales were between 72 and 75 at the 2-, 5- and 10-year follow-up. The 5-year revision rate was 9.9%.

Conclusion: There was a major increase in incidence of pediatric ACLR in Norway during the study period. There was a shift in the approach to concomitant meniscal procedures from resection to repair, with more than a doubling of the proportion of meniscal repairs. Patient-reported outcomes revealed long-lasting reduced knee function.

Keywords: ACL injury; ACL reconstruction; incidence; pediatric; register.

Figure 1.

Study flowchart. Asterisk (*) denotes the number of primary anterior cruciate ligament reconstruction (ACLR) cases. Out of 1484 ACLR cases, 8 were bilateral, resulting in a total of 1476 patients with ACLR. The KOOS response rate is presented with the number of responses received. The percentages reflect the proportion of patient responses relative to the total number of patients who had reached sufficient follow-up time for that specific time point. NKLR, Norwegian Knee Ligament Register; KOOS, Knee injury and Osteoarthritis Outcome Score.

Figure 2.

(A) Yearly incidence of pediatric anterior cruciate ligament reconstruction (ACLR) for boys (10-16 years), girls (10-14 years), and both sexes combined (total), per 100,000 population. (B) Three-year moving average of the incidence per 100,000 population, by sex.

Figure 3.

Activity at injury (in percentages), by age. Of all the injuries, 96.4% were sports-related. “Other” represents a range of other sports, such as basketball, floorball, and martial arts.

Figure 4.

Choice of graft per year, in percentages. “Other” represents sutures and allografts. BPTB, bone–patellar tendon–bone.

Figure 5.

Kaplan-Meier survival curves for revision surgeries for (A) all patients (B) and those who received a bone–patellar tendon–bone autograft (BPTB) or hamstring tendon autograft.

Figure 6.

Knee injury and Osteoarthritis Outcome Score (KOOS) preoperatively (Pre-op) and at the 2-, 5-, and 10-year follow-up visits, with 95% CI. A score of 100 indicates no symptoms, and 0 indicates severe knee problems. For missing data, see the flowchart in Figure 1. ADL, Activities of Daily Living; QoL, Quality of Life; Sport/Rec, Sport and Recreation.