The Effect of Hinge Position on Posterior Tibial Slope in Medial Open-Wedge High Tibial Osteotomy.
OBJECTIVE
To evaluate whether hinge position affects the change in posterior tibial slope in medial open-wedge high tibial osteotomy (HTO).


METHODS
We retrospectively evaluated 19 knees from 17 patients who underwent medial open-wedge HTO by 3-dimensional computed tomography scan before and after surgery. A 3-dimensional image model was constructed by applying reverse-engineering software to the computed tomography DICOM (Digital Imaging and Communications in Medicine) files. The hinge axis (i.e., the position of the hinge compared with the anteroposterior axis on an axial view), posterior tibial slope, medial-proximal tibial angle, and gap ratio (i.e., the ratio of anterior gap to posterior gap in the opened wedge) were measured.


RESULTS
The mean hinge axis was 4.92° ± 3.86°. Posterior tibial slope increased from 7.29° ± 2.56° preoperatively to 10.48° ± 3.01° postoperatively (P = .001). The mean medial-proximal tibial angle was 85.96° ± 1.97° preoperatively and 93.13° ± 3.17° postoperatively (P = .001). The mean gap ratio was 62.48% ± 7.26%. Linear regression analysis determined that the hinge axis (P = .0001) was a significant factor changing posterior tibial slope.


CONCLUSIONS
Hinge position affected the change in posterior tibial slope in medial open-wedge HTO; in particular, a posterolateral hinge position led to an increase in posterior tibial slope.


METHODS
Level IV, therapeutic study.
Department of Orthopaedic Surgery, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Republic of Korea.
Sang Won
SW
Moon
Department of Orthopaedic Surgery, Soonchunhyang University Hospital Bucheon, Gyeonggi-do, Republic of Korea.
Sin Hyung
SH
Park
Department of Orthopaedic Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea.
Byung Hoon
BH
Lee
Clinical Trial Center, Inje University Busan Paik Hospital, Busan, Republic of Korea.
Minkyung
M
Oh
School of Mechanical Engineering, Korea University, Seoul, Republic of Korea.
Minho
M
Chang
Department of Orthopaedic Surgery, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
Jin Hwan
JH
Ahn
Department of Orthopaedic Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea. Electronic address: mdwang88@gmail.com.
Joon Ho
JH
Wang
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D010027:Osteotomy / Q000379:methods*; D019736:Prostheses and Implants; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D055815:Young Adult