Table 1.

Pearls and Pitfalls

Contraindications •Grade IV osteoarthritis according to Kellgren–Lawrence classification •Abnormal lateral plateau slope (>15°) •Fixed flexion contracture •Substantial recurvatum (>10°)

Pearls •Careful 3-dimensional preoperative planning to understand impact of saw cutting plane, hinge position and wedge insertion on medial and lateral tibial plateau slope modification •Hardware removal before PSCG positioning to avoid errors •The deepest part of the patellar tendon needs to be cleared to create enough space for the anterior bracket of the PSCG •Saw-blade marking to avoid posterolateral effraction •The most anterior screw of the plate has to be inserted after the graft fixation because of its close position with the tibial tunnel

Advantages •Virtual osteotomy performed with 3-dimensional planning, allowing direct understanding of the process •Very accurate and reproducible method for frontal and sagittal tibial abnormalities correction •Fewer fluoroscopic images taken •Intact TT preserving the extensor mechanism and allowing accurate positioning of the osteotomy at the appropriate level •PSCG and plate positioning guiding the opening wedge to correction perfection •ACL tunnel connected to screw position to avoid conflicts •No modification of patellar height

Potential risks and disadvantages •Damage to the popliteal vessels and nerves •Hinge breakage •Delayed union and non-union •Infection •Hardware removal •Longer surgery in our hands (total 2 hours 30) as compared with isolated ACL revision (1 hour) and high tibial osteotomy (1 hour) •Long rehabilitation and delayed return to sports activities (12 months)

ACL, anterior cruciate ligament; PSCG, patient-specific cutting guide; TT, tibial tuberosity.