Long Term Failure of Thermal Shrinkage for Partial Tears of the
ACL
Authors:
Jeffrey L. Halbrecht MD, California
Pacific Medical Center, San Francisco, CA
Objective: A prospective study was undertaken to determine the
effectiveness of thermal shrinkage for partial tears of the ACL
and for stretched ACL grafts.Methods: Eighteen patients underwent thermal shrinkage for partial tears
of the ACL (13) or stretched grafts (5). Intraoperative KT1000
values were obtained to measure shrinkage at time zero. Folow
up was performed at 6 months, 1 year and 5 years using
KT1000 arthrometer measurements, Cincinnati and Lysholm
knee scores as well as subjective assessment.Results: Intraoperative shrinkage averaged 2.08 mm ( 16.6% ) based on
same side KT 1000 manual maximum testing pre and post
shrinkage. At 6 months follow up, all patients were stable with a
negative Lachman test and average KT1000 manual max side to
side difference of 1.06 mm. At 1 year, one patient had failed,
going on to complete rupture. For the remaining patients,
average KT1000(max) side to side difference at 1 year remained
stable at 1.1mm. Cincinnati Scores improved from 53 to 89.
Lysholm scores improved from 55 to 89. At 5 year follow up, 11
out of 14 patients available for evaluation had gone on to
complete failure requiring reconstruction.Conclusions: Thermal shrinkage provides only short term benefit for partial
tears of the ACL or stretched grafts, and leads to catastrophic
failure in the majority of patients at long term follow up. Based on
this data, thermal shrinkage cannot be recommended for
treatment of partial tears of the ACL or stretched grafts.
