title: Association of fibrosis in the infrapatellar fat pad and degenerative cartilage change of patellofemoral joint after anterior cruciate ligament reconstruction.
abstract: BACKGROUND
  The purpose of this study was to evaluate the prevalence and risk factor of cartilage degeneration of the patellofemoral joint (PFJ) that was diagnosed by second-look arthroscopy.
  
  
  METHODS
  One-hundred and seven patients who underwent ACL reconstruction were evaluated by preoperative MRI, postoperative MRI and second-look arthroscopy. Severity of infrapatellar fat pad (IPFP) fibrosis was evaluated by MRI at an average of 26months after ACL reconstruction. Cartilage degeneration was assessed by second-look arthroscopy at 29months.
  
  
  RESULTS
  Twenty-five patients (24.0%) showed cartilage degeneration of the PFJ in second-look arthroscopy. Patients were divided into three groups according to severity of IPFP fibrosis of postoperative MRI (i.e. Group A, focal and incomplete band fibrosis, n=69; Group B, complete band fibrosis, n=31; and Group C, diffuse and infiltrated fibrosis, n=7). Cartilage degeneration of the PFJ was significantly worsened with more fibrosis formation of the IPFP (P<0.001). Other factors for instabilities (BMI, age, concomitant meniscal procedure, time from injury to reconstruction, severity of IPFP fibrosis at preoperative MRI and clinical scores) were not correlated with cartilage degeneration of the PFJ. The multivariate logistic regression analysis of degeneration of the PFJ after ACL reconstruction identified more severe fibrosis tissue formation of the IPFP and initial cartilage defect as significant predictors.
  
  
  CONCLUSIONS
  More extensive fibrosis of the IPFP and initial cartilage defect may be related to further degenerative changes of the PFJ. Other factors did not affect cartilage degeneration of the PFJ, although the muscle strength, the individual activity level or the rehabilitation protocol was not evaluated in the short-term follow-up period.
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, Seoul, Republic of Korea.
authors.forename: Kyoung Ho
authors.initials: KH
authors.lastname: Yoon
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, Seoul, Republic of Korea.
authors.forename: Dae Hyun
authors.initials: DH
authors.lastname: Tak
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, Seoul, Republic of Korea.
authors.forename: Taeg Su
authors.initials: TS
authors.lastname: Ko
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, Seoul, Republic of Korea.
authors.forename: Sang Eon
authors.initials: SE
authors.lastname: Park
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, Seoul, Republic of Korea.
authors.forename: Juhyun
authors.initials: J
authors.lastname: Nam
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee University School of Medicine, Seoul, Republic of Korea. Electronic address: sangdory@hanmail.net.
authors.forename: Sang Hak
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects*; D001182:Arthroscopy; D002357:Cartilage Diseases / Q000209:etiology / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D057071:Patellofemoral Joint / Q000473:pathology*; D015995:Prevalence; D012307:Risk Factors; D024162:Second-Look Surgery; D055815:Young Adult
keywords: Anterior cruciate ligament; Cartilage degeneration; Infrapatellar fat pad; Magnetic resonance imaging; Patellofemoral joint