Characteristics of inpatient anterior cruciate ligament reconstructions and concomitant injuries

Purpose: The purpose of this epidemiologic study was to quantify the incidence, expense, and concomitant injuries for anterior cruciate ligament reconstruction (ACLR) procedures in the USA from 2003 to 2011 that required an inpatient stay. It was hypothesized that the relative reported rates of concomitant knee injuries would be greater with the MCL and menisci compared to all other concomitant knee injuries. Methods: The National Inpatient Sample from 2003 to 2011 was retrospectively sampled using ICD-9-CM codes to identify ACLR patients and to extrapolate national averages. Results: Between the years of 2003–2011, an average of 9,037 ± 1,728 inpatient hospitalization included ACLRs, of which 4,252 ± 1,824 were primarily due to the ACLR. Inpatient visits primarily due to ACLR involved an average hospitalization of 1.7 ± 0.2 days and cost $30,118 ± 9,066 per patient. Knee injuries that were commonly reported along with inpatient ACLRs included medial meniscus damage (18.1 %), lateral meniscus damage (16.8 %), collateral ligament repairs (12.3 %), and medial collateral ligament strains (6.9 %). Prevalence of meniscus injuries was consistent across years, but MCL-related injuries increased over time. Conclusions: ACLR-related inpatient hospitalizations account for approximately 7.1 % of the total ACLRs performed annually in the USA. Inpatient ACLR procedures continue to decrease in frequency; however, the mean cost per patient increased. Meniscus and collateral ligament injuries were the most commonly reported concomitant knee injuries. The clinical relevance of this investigation is that it informs, on a large clinical cohort of patients, the current state of incidence and expense for ACLR surgeries in an inpatient setting. Level of evidence: Prognostic, retrospective study, Level II.