Analysis of Mechanical Loading after Anatomic Anterior Cruciate Ligament Reconstruction Using Combined Single-Photon Emission Computerized Tomography and Conventional Computerized Tomography

Purpose: This study was to evaluate changes of the mechanical loading pattern after anatomic anterior cruciate ligament (ACL) reconstruction by analyzing uptake patterns using combined single-photon emission computerized tomography and conventional computerized tomography (SPECT/CT). Materials and Methods: On SPECT/CT, high signal intensity of the articular surface which shows biological activity and mean increase of mechanical loading was compared with that of the tibiofemoral shaft as a comparative signal. The proportion of positive signals was evaluated in all compartments of the operated knee. Analysis was performed according to combined injury. Results: A relatively high proportion of positive signals was detected in the posterior zone of the lateral tibial plateau (23.5%) and trochlear groove (23.5%) although increased signal intensity was detected in all compartments. There was no statistical difference depending on the presence of combined injury and between single-bundle and double-bundle ACL reconstruction. Conclusions: Following anatomic ACL reconstruction, higher signal intensity was detected, particularly in the posterior part of the lateral tibial plateau and trochlear groove. Close observation for further signal changes or osteoarthritic changes would be required even if there was no combined injury and anatomic reconstruction was performed.