| Purpose: The biomechnical test section of this study was intended to investigate the biomechanical comparison of channel-assisted minimally invasive repair and 4 common achilles tendon repair techniques in a vitro model by progressive rehabilitation program and unidirectional tensile loading program. Meanwhile,the clinical section was intended to investigate the comparison of channel-assisted minimally invasive repair and Krackow open repair technique by a retrospective analysis.Methods: Biomechnical test section: 84 samples of Achilles tendon which had passed the consistency test were randomly averaged into two groups: group A and group B.Group A were tested with progressive rehabilitation program, while, group B were tested with unidirectional tensile loading program.1.Group A was averaged into 6 subgroups (7 in each group): CAMIR, Krackow,Ma-Griffith, Achillon, PARS, CAMIR-5 group. Each tendon was pre-tensioned to 50N for 2minutes to remove slack from the construct. Each specimen was subjected to a loading protocol representative of a progressive, postoperative rehabilitation program(3000 total cycles) consisting of cyclic loading stages of 1000 cycles at 1 Hz: (1) 20-100 N, (2) 20-191 N, and (3) 20-369 N. Failure was defined as tendon breakage, suture breakage, or suture pullout. Cyclics and elongation were monitored and recorded continuously throughout testing by the dynamometer.Group B was averaged into 6 subgroups (7 in each group): CAMIR, Krackow,Ma-Griffith, Achillon, PARS, CAMIR-5 group. Each tendon was pre-tensioned to 50N for 2minutes to remove slack from the construct, and then was loaded to failure with the rate of 20mm/s. Then it was monitored and recorded continuously throughout testing about the elongation of 100N, 191N, 369N and failure, and the maximum loading of failure by the dynamometer. Stiffness was calculated by determining the slope of the force-displacement curve in the linear region.Failure was defined as tendon breakage, suture breakage, or suture pullout.Clinical application section: A retrospective analysis was included comparing CAMIR and Krackow repair of ruptured Achilles tendon, those whom in our department from January, 2013 to February, 2016. One hundred and seventy five patients were identified; 75 underwent CAMIR repair and 60 had a traditional open Krackow repair.The length of the main incision, the last time of operation, the sural nerve injury, the infection, the deep vein thrombosis, the re-rupture, the total complication rate and the AOFAS ankle-hind foot function Score were recorded and compared with those of the two groups comprehensively.Results: Biomechnical test section: 1.Group A: Elongation: after 10 cycles, the elongations of all subgroups have no significant difference. After 1000 cycles, the elongation of CAMIR (7.51±1.77mm) had no difference with Krackow (7.32 ±1.09mm)、Ma-Griffith (8.63 ± 1.29mm) (p=0.107),but longer than Achillon(3.19±0.57mm) (p=0.000) and PARS (3.73±0.66mm) (p=0.000). After 10 and 2000 cycles, the elongation of CAMIR-5 had no difference with Achillon and PARS(p=0.569). The cycles when the contractions failure: CAMIR 1000 cycles, Krackow 1000 cycles, Ma-Griffith 1000 cycles, Achillon 2000 cycles, PARS 2000 cycles,CAMIR-5 2000 cycles.2. Group B: There were no difference in the elongation of 100N, the maximum loading of failure and stiffness between CAMIR and Krackow, Ma-Griffith. But CAMIR group repairs were longer than Achillon group (p=.000) and PARS (.000) group in the elongation of 100N and lower than Achillon group (p=.000) and PARS (.000)group in the maximum loading and stiffness. However, there were no differences between the CAMIR-5 group and Achillon and PARS groups in the elongation of 100N and failure, maximum loading and stiffness.3. The number of stands and knots of the repair constraction: CAMIR- 1,1;Krackow- 1,1; Ma-Griffith- 1,1; Achillon- 3,3; PARS- 3,3.Clinical application section: 1. The total complication rate was 4.0% in the CAMIR group and 16.7% in the Krackow group. There was no statistically significant difference between the two groups.2. The operation time with CAMIR repair was 23.9±4.5min compared to 40.4±8.0min in open Krackow group (p=0.000). The length of main incision with CAMIR repair (2.0±0.2mm) was significantly lower than that in open Krackow group(8.3±0.9mm) (p=0.000).3. The mean duration in hosiptial after operation with CAMIR repair (1.84 days)was significantly lower than that in open Krackow group (4.25 days) (p=0.000). While,there was no difference with injury / uninjury calf circumference ratio and the AOFAS ankle-hind foot function Scores between the two groups (p=0.835, p=0.638).Conclusion: 1. There were no difference between CAMIR and open Krackow repair and minimally invasive Ma-Griffith repair techniques, which can provide a reliable mechanical strength for repair. 2. In the same suture, CAMIR suture is weaker than that of Achillon and PASR. 3. For athletes who need greater suture strength, you can choose a higher strength suture for CAMIR minimally invasive operation. 4. CAMIR not only can provide reliable mechanical strength but also has less suture strands and knots,which can reduce the risk of suture reactivity and better for healing. 5. CAMIR minimally invasive system is not only easy to master, but also to avoid sural nerve injury maximum extently compared with other minimally invasive suture. Compared with the traditional repair, it can play a minimally invasive advantage, significantly reducing incision infection, deep Venous thrombosis. CAMIR technique is worth to be promoted in a wide range of hospitals. |
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