Improved divergence angles with femoral interference screw placement through the tibial tunnel as measured by multiplanar reconstruction computed tomography.
OBJECTIVE
A modified technique for anterior cruciate ligament (ACL) reconstruction without graft injury by femoral interference screw insertion directly through the tibial tunnel is reported. This study evaluated femur bioabsorbable interference screw divergence and obliquity of the graft and tunnel positions as measured by multiplanar reconstruction computed tomography (MPR-CT) after endoscopic ACL reconstruction.


METHODS
Twenty-five patients who underwent single-incision arthroscopically assisted ACL reconstruction using hamstring tendon autografts were enrolled in this prospective study. All procedures were performed using the same technique: femoral bioabsorbable interference screw insertion directly through the tibial tunnel. Divergence angles of oblique sagittal and oblique axial views of the graft and tunnel positions using MPR-CT evaluation were obtained. CT images were evaluated in a blinded manner by 3 experienced radiologists.


RESULTS
The average divergence angles in oblique sagittal and oblique axial views were 0.88 +/- 1.06 and 1.44 +/- 1.17, respectively. Sagittal, axial, and coronal obliquity of the graft in reconstructed patients averaged 64 degrees (range, 46 degrees to 69 degrees ), 19 degrees (range, 17 degrees to 22.5 degrees ), and 73.6 degrees (range, 70 degrees to 77.6 degrees ), respectively. Radiologic analysis of the femoral insertion according to the quadrant technique showed that the femoral center of the anteromedial (grafted) bundle was 18.6% and 23.6% of the depth of Blumensaat's line and the height of the femoral condyle. At the tibia, the tibial ACL attachment at the center of the anteromedial bundle was at 41.1% of the maximal tibial diameter.


CONCLUSIONS
Our study showed that MPR-CT is a useful diagnostic tool for evaluation of the femoral interference screw divergence, obliquity of the graft, and the exact femoral and tibial insertion site of the graft. The screw will have little or no divergence using this novel technique as measured by the very accurate MPR-CT.


METHODS
Level IV, therapeutic case series.
Chan
Yi-Sheng
YS
Division of Sports Medicine, Department of Orthopaedic Surgery, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan, Republic of China. chan512@adm.cgmh.org.tw
Lo
Yang-Pin
YP
Lien
Li-Chang
LC
Fu
Chen-Ju
CJ
Wan
Yung-Liang
YL
Hsu
Kuo-Yao
KY
Wang
Ching-Jen
CJ
Chen
Wen-Jer
WJ
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy / Q000379:methods; D001863:Bone Screws; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology; D019651:Plastic Surgery Procedures / Q000379:methods*; D012421:Rupture; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult