title: Operative Management of Patellar Instability in the United States: An Evaluation of National Practice Patterns, Surgical Trends, and Complications.
abstract: BACKGROUND
  Treatment of patellofemoral instability has evolved as our understanding of the relevant pathoanatomy has improved. In light of these developments, current practice patterns and management trends have likely changed to reflect these advancements; however, this has not been evaluated in a formal study.
  
  
  OBJECTIVE
  To determine nationwide patient demographics, surgical trends, and postoperative complications associated with the operative management of patellar instability surgery.
  
  
  METHODS
  Descriptive epidemiological study.
  
  
  METHODS
  A large private-payer database (PearlDiver) comprising patients covered by Humana and United Healthcare insurance policies was retrospectively reviewed using Current Procedural Terminology (CPT) codes to identify patients who underwent surgery for patellar instability. The study cohort was established by querying for patients billed under CPT codes 27420, 27422, or 27427 while satisfying the diagnostic requirement of patellar instability (International Classification of Diseases-9th Revision codes 718.36, 718.86, or 836.3). Patient demographics, surgical trends, concomitant procedures, and postoperative complications were determined.
  
  
  RESULTS
  A total of 6190 patients underwent surgical management for patellar instability. Adolescents (age range, 10-19 years) represented 51.5% of cases, and 59.6% were female. The number of patellar instability procedures increased annually over the study period in both the Humana (P = .004, R (2) = 0.76) and United Healthcare (P = .097, R (2) = 0.54) cohorts. The most common concomitant procedures were lateral retinacular release (43.7%), chondroplasty (31.1%), tibial tubercle osteotomy (13.1%), removal of loose bodies (10.5%), osteochondral grafting (9.5%), and microfracture surgery (9.5%). Manipulation under anesthesia was required in 4.6% of patients within 1 year. Patellar fracture within 1 year and infection within 30 days occurred in 2.1% and 1.2% of patients, respectively.
  
  
  CONCLUSIONS
  Patellar instability surgery has increased over the past decade. This finding may be attributed to growing clinical evidence to support these procedures as well as increased surgeon familiarity and comfort with these specific techniques. We observed an unexpectedly high rate of concomitant lateral retinacular release. Overall, the rates of commonly recognized complications (stiffness, patellar fracture, and postoperative infection) were similar to those observed in smaller case series.
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
authors.forename: Armin
authors.initials: A
authors.lastname: Arshi
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
authors.forename: Jeremiah R
authors.initials: JR
authors.lastname: Cohen
authors.affiliation: Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Wang
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Hame
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: McAllister
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
authors.forename: Kristofer J
authors.initials: KJ
authors.lastname: Jones
keywords: MPFL reconstruction; dislocation; patella; patellar instability surgery; patellofemoral