Histology of the torn meniscus: a comparison of histologic differences in meniscal tissue between tears in anterior cruciate ligament-intact and anterior cruciate ligament-deficient knees.
OBJECTIVE
The purpose of this case control study was to evaluate possible preexisting structural differences between torn menisci in anterior cruciate ligament-intact and anterior cruciate ligament-deficient knees.


METHODS
Subjects were prospectively enrolled into the study from new patient referrals to the orthopaedic clinic. Forty-four meniscal specimens were retrieved during routine arthroscopy. The anterior cruciate ligament-deficient group included 24 patients (15 men and 9 women, average age of 26.5 years, SD = 9.5) with 24 acute, displaced, longitudinal, bucket-handle tears of the medial meniscus in unstable, anterior cruciate ligament-deficient knees. The anterior cruciate ligament-intact group included 20 patients (14 men and 6 women, average age of 30.4 years, SD = 13.4) with similar tears in anterior cruciate ligament-intact knees. Longitudinal and transverse section specimens were stained with hematoxylin and eosin and safranin O, divided into zones based on proximity to the tear, and graded on safranin O uptake or tissue composition.


RESULTS
Descriptive statistics and chi2 analyses were used to assess differences between groups within each zone. Significant differences (P < .05) were observed between anterior cruciate ligament-deficient and anterior cruciate ligament-intact specimens stained with hematoxylin and eosin in zone 3 for both transverse and longitudinal cuts. Significant differences were not found between anterior cruciate ligament-deficient and anterior cruciate ligament-intact specimens stained with safranin O.


CONCLUSIONS
Longitudinal meniscal tears occurring in anterior cruciate ligament-intact knees may result from early degenerative disease processes. Attempted repair of this diseased tissue may fail to have a positive effect on long-term preservation of the meniscus.
Meister
Keith
K
Division of Sports Medicine, Department of Orthopaedics and Rehabilitation, University of Florida, Gainesville, Florida, USA. keith-meister@ufl.edu
Indelicato
Peter A
PA
Spanier
Suzanne
S
Franklin
John
J
Batts
Joel
J
D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy; D004396:Coloring Agents; D004801:Eosine Yellowish-(YS); D005260:Female; D005456:Fluorescent Dyes; D006416:Hematoxylin; D006801:Humans; D007718:Knee Injuries / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D010619:Phenazines; D011446:Prospective Studies; D012307:Risk Factors; D000070600:Tibial Meniscus Injuries
D004396:Coloring Agents; D005456:Fluorescent Dyes; D010619:Phenazines; D004801:Eosine Yellowish-(YS); C009195:safranine T; D006416:Hematoxylin