The effect of gap formation at the repair site on the strength and excursion of intrasynovial flexor tendons - An experimental study on the early stages of tendon-healing in dogs

Citation
Rh. Gelberman et al., The effect of gap formation at the repair site on the strength and excursion of intrasynovial flexor tendons - An experimental study on the early stages of tendon-healing in dogs, J BONE-AM V, 81A(7), 1999, pp. 975-982
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Ortopedics, Rehabilitation & Sport Medicine","da verificare
Journal title
JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME
ISSN journal
0021-9355 → ACNP
Volume
81A
Issue
7
Year of publication
1999
Pages
975 - 982
Database
ISI
SICI code
0021-9355(199907)81A:7<975:TEOGFA>2.0.ZU;2-C
Abstract
Background Elongation (gap formation) at the repair site has been associate d with the formation of adhesions and a poor functional outcome after repai r of flexor tendons. Our objectives were to evaluate the prevalence of gap formation in a clinically relevant canine model and to assess the effect of gap size on the range of motion of the digits and the mechanical propertie s of the tendons. Methods: We performed operative repairs after sharp transection of sixty-fo ur flexor tendons in thirty-two adult dogs, Rehabilitation with passive mot ion was performed daily until the dogs were killed at ten, twenty-one, or f orty-two days postoperatively. Eight tendons ruptured in vivo. In the fifty -six intact specimens, the change in the angles of the proximal and distal interphalangeal joints and the linear excursion of the flexor tendon were m easured as a 1.5-newton force was applied to the tendon, The gap at the rep air site was then measured, and the isolated tendons were tested to failure in tension. Results: Twenty-nine tendons had a gap of less than one millimeter, twelve had a gap of one to three millimeters, and fifteen had a gap of more than t hree millimeters, Neither the time after the repair nor the size of the gap was found to have a significant effect on motion parameters (p > 0.05); ho wever, the ultimate force, repair-site rigidity and repair-site strain at t wenty newtons were significantly affected by these parameters (p < 0.05). T esting of the tendons with a gap of three millimeters or less revealed that , compared with the ten-day specimens, the forty-two-day specimens failed a t a significantly (90 percent) higher force (p < 0.01) and had a significan tly (320 percent) increased rigidity (p < 0.01) and a significantly (GO per cent) de-creased strain at twenty newtons (p < 0.05), In contrast, the tens ile properties of the tendons that had a gap of more than three millimeters did not change significantly with time. Conclusions: Our data indicate that, in a dog model involving sharp transec tion followed by repair, a gap at the repair site of more than three millim eters does not increase the prevalence of adhesions or impair the range of motion but does prevent the accrual of strength and stiffness that normally occurs with time. Clinical Relevance: Tendons that have a large gap are at increased risk for rupture during early rehabilitation, and this risk of rupture does not dec rease in the first six weeks.