The Clinical Study Of Tibial Tunnel Enlargement After Anterior Cruciate Ligament Reconstructions

Objective:The aim of this study was to observe the tibial tunnel enlargement, the related influence factors and its relationship with clinical outcome after autologous semitendinosus and gracilis tendons single bundle of anterior cruciate ligament(ACL) reconstruction.Method:Retrospective study, from May 2011 to December 2012, we collected 40 patients who received single-bundle anterior cruciate ligament reconstruction in affiliated hospital of chengde medical college.All the operations were completed by only one doctor who was an senior arthroscopic surgeon. All cases used the unified postoperative rehabilitation plan to guide function exercise. All postoperative follow-up of patients with 18 months at least, the follow-up contents as follows: 1. Conventional physical examination of knee joint: range of motion(ROM), anterior drawer test(ADT), Lachman Test, pivot shift test(PST); 2. Using the Lysholm Knee Scoring Scale and IKDC2000 Scoring Scale to evaluate joint function; 3. Imageological diagnosis: X-ray films, CT scanning, and three-dimensional reconstruction. Measuring the tibia tunnel on the images: the length of the bone tunnel and the length without interference screw, the diameter of three points of the tunnel(entrancy, nail head, exit). The definition of bone tunnel diameter was the distance between the sclerosis of two bone tunnel wall, the measure diameter was perpendicular to the long axis of the bone tunnel. The absolute value of bone tunnel enlargement was the diameter of the tunnel minus the diameter of drill, and the percentile was the absolute value divided by the diameter of drill. According to the classification standard of Peyrache MD[1], The bone tunnel enlargement can be divided into 4 Level: Level 0<2mm, Level 1--2~4mm, Level 2 4~6mm, level 3≥6mm. In accordance with past practice, The definition of bone tunnel enlargement is the bone tunnel diameter of absolute value is greater than 2mm or the percentile is greater than 30%. We observe the rate and the degree of enlargement of tibia tunnel widening after ACL reconstruction, and to assess the correlated between proportion of the length of tibia tunnel without interference screw with tibial tunnel enlargement, and to assess the effect on short and mid-term clinical outcomes of bone tunnel enlargement.Results:In this research, the rate of entrancy of A-P and lateral plain film was 52.5%(21/40) and 47.5%(19/40), the enlargement degree was 2.64 mm and 2.67 mm. the rate of exit of A-P and lateral plain film was both 62.5%(25/40), the enlargement degree was 2.77 mm and 2.83 mm. The rate of three-dimensional CT coronal and sagittal measuring tibia bone tunnel entrancy rate is 52.5%(21/40)and 47.5%(19/40), the enlargement degree was 2.67 mm and 2.67mm; the rate of nail head enlargement was both 40.0%(16/40), the enlargement degree was 1.81 mm and 1.82mm;the rate of exit enlargement was both 55.0%(22/40), the enlargement degree was 2.56 mm and 2.56 mm.According to the classification standard of bone tunnel by Peyrache[1], the tibial tunnel entrancy enlargement in A-P X-ray: level 0 had 19 cases,and level 1 had 13 cases, and level 2 had 8 cases. The tibial tunnel exit enlargement in A-P X-ray: level 0 had 15 cases,and level 1 had 16 cases, and level 2 had 9 cases. The tibial tunnel entrancy enlargement in lateral level 0 had 21 cases,and level 1 had 11 cases,and level 2 had 8 cases. the tibia bone tunnel exit enlargement in lateral level 0 had 15 cases,and level 1 had 16 cases,and level 2 had 9 cases. The tibial tunnel entrancy enlargement in coronary of 3D-CT: level 0 had 17 cases,and level 1 had 16 cases,and level 2 had 7 cases. The tibial tunnel exit enlargement in coronary of 3D-CT: level 0 had 21 cases, and level 1 had 12 cases, and level 2 had 7 cases. The tibial tunnel entrancy enlargement in sagittal of 3D-CT: level 0 had 21 cases,and level 1 had 11 cases, and level 2 had 8 cases. The tibial tunnel exit enlargement in sagittal of 3D-CT: level 0 had 19 cases,and level 1 had 16 cases,and level 2 had 5 cases. There were no level 3 patients in all case.This study using three-dimensional CT to measure the tibial tunnel length was 35.29±3.23 mm, the length without interference screw was 7.50±0.61 mm, the proportion of the total length of bone tunnel was(21.30±0.80)%. The proportion of tibial tunnel without interference screw had correlation with bone tunnel entrancy enlargement( r =0.36, P =0.023).Postoperative follow-up found no activity disabilities joint flexion and extension, Affected limb flexion angle was(130.13±5.37)°,the contralateral limb was(132.25 ± 4.93) °. There was no statistically significant difference( t =-1.844, P =1.844).We defined the diameter value of bone tunnel exceed 2mm as bone tunnel enlargement, all follow-up objects was divided into enlargement and the non-enlargement group according to the degree of tibia bone tunnel entrancy enlargement, there was no statistically significant difference between the two groups in ADT、Lachman test and PST( t =1.314,0.011,0.005, P =0.33、1.0、1.0).40 patients with preoperative Lysholm score was(46.33±6.62), postoperation score was(93.23±2.50), there was no statistically significant difference( t =-45.50, P <0.001).40 patients with preoperative IKDC score was(53.05±8.33), postoperation score was(86.68±1.87), there was no statistically significant difference( t =-25.18, P <0.001).According to tibial tunnel diameterof 3D-CT, Lysholm score between bone tunnel enlargement as follows: level 0(93.43±2.60), level 1(93.73±2.53), level 2(92.0±2.0), there was no statistically significant difference among all Lysholm score in different levels( F =1.274, P =0.292), there was no statistically significant difference between any two levels.Conclusion1 After ACL reconstruction under arthroscopy may appear bone tunnel widening phenomenon, the enlargement position mainly located in the entrancy(close to the articular surface) of bone tunnel.2 The tibial tunnel without interference screw of tunnel length has correlation with bone entrancy enlargement.3 ACL reconstruction under arthroscopy surgery can obviously improve the instability of knee, knee score, and function of knee joint.4 The tibial tunnel enlargement after ACL reconstruction had no significant effect on short and mid-term clinical outcomes. Conclusion:...