Is Notchplasty a Problem?
April 1, 2002 2 minutes read
Is Notchplasty a Problem?
Abstract & Commentary
Synopsis: Notchplasty, previously considered an integral part of ACL reconstruction, may have detrimental effects on ACL graft biomechanics.
Source: Markolf KL, et al. Am J Sports Med. 2002;30:83-89.
Notchplasty was once an integral part of ACL reconstruction. Recent studies have suggested that only a "minimal" notchplasty is required, and many lecturers on ACL reconstruction have suggested recently that they no longer routinely perform a notchplasty as a part of ACL reconstruction. In the present study, 26 fresh-frozen cadavers were studied. Two groups, consisting of 15 and 11 specimens respectively, had a 2-mm and a 4-mm notchplasty prior to biomechanical testing. Through an elaborate testing design and instrumentation, graft tension was measured before and after notchplasty. The mean intra-articular pretension required to restore normal anterior-posterior laxity at 30° of flexion was 27 N before notchplasty, 48 N after a 2-mm notchplasty, and 65 N after a 4-mm notchplasty. Mean graft forces increased dramatically after notchplasty at both 30° and 90° of flexion. Markolf and colleagues caution that these changes may affect the clinical success of ACL reconstructions.
Comment by Mark D. Miller, MD
Following notchplasty, knee laxity was greater in full extension and less in flexion. Wouldn’t this be both bad (in extension) and good (in flexion) news? The answer is no—knee laxity is not good in ACL reconstruction, but too much tension is not good either. As patients work in rehab to get their motion postoperatively, it puts too much tension on the graft and may lead to excessive graft stretching. It would appear from these results that notchplasty may affect tunnel placement and graft isometry in a negative fashion.
Markolf et al also showed the benefit of adequate pretensioning of the graft. This should be done clinically with the use of a graft table and cycling the knee prior to graft fixation. Although the ideal amount of graft tension is still very much a matter of debate, graft pretensioning is recommended. The real issue with all of these studies, of course, is whether in vitro experimental data can be directly applied in the operating room. With all of the recent studies on commonly held precepts of ACL surgery, how have any of our grafts survived at all, let alone have an excellent record of clinical success? The take home message, however, reflects current clinical trends—as far as notchplasty goes, less is better.
Dr. Miller, Associate Professor, UVA Health System, Department of Orthopaedic Surgery, Charlottesville, VA, is Associate Editor of Sports Medicine Reports.
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