title: In vivo changes after mechanical injury.
abstract: Chondrocytes undergo apoptosis in response to mechanical injury in vitro. The current clinical study correlates arthroscopic and magnetic resonance imaging results with biopsy specimens of cartilage from patients with knee injury. Twenty patients were evaluated at a mean 2.7 months after acute knee injury. The mean age of the patients was 32 years and the mean weight was 83 kg. Cartilage lesions were graded separately on magnetic resonance images and arthroscopy in a blinded manner. During arthroscopy, a 1.8 mm diameter biopsy specimen was obtained from the edge of cartilage lesion. The biopsy specimen underwent histologic examination by safranin O staining and detection of chondrocyte apoptosis by the presence of deoxyribonucleic acid fragmentation. There was a positive correlation in 50% (10 of 20) when the presence or absence of cartilage lesions by magnetic resonance imaging was correlated with arthroscopy. All cases of partial thickness or full-thickness cartilage loss that were seen by arthroscopy also were detected by magnetic resonance images. Apoptotic cells were significantly more numerous in biopsy specimens from lesions compared with control biopsy specimens. The findings of reduced cell viability attributable to apoptosis may have profound implications for cartilage repair. This opens potential therapeutic avenues for the treatment of posttraumatic cartilage lesions through apoptosis prevention.
authors.affiliation: Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, CA 92037, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Colwell
authors.forename: D D
authors.initials: DD
authors.lastname: D'Lima
authors.forename: H R
authors.initials: HR
authors.lastname: Hoenecke
authors.forename: J
authors.initials: J
authors.lastname: Fronek
authors.forename: P
authors.initials: P
authors.lastname: Pulido
authors.forename: B A
authors.initials: BA
authors.lastname: Morris
authors.forename: C
authors.initials: C
authors.lastname: Chung
authors.forename: D
authors.initials: D
authors.lastname: Resnick
authors.forename: M
authors.initials: M
authors.lastname: Lotz
mesh_terms: D000328:Adult; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000293:injuries* / Q000473:pathology*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male