Precise arthroscopic mini-trochleoplasty combined with medial patellofemoral ligament reconstruction yields comparable complications to isolated medial patellofemoral ligament reconstruction

Figure 1 Flowchart of the patient selection. Precise arthroscopic mini-trochleoplasty precise arthroscopic mini-trochleoplasty, medial patellofemoral ligament reconstruction medial patellofemoral ligament reconstruction. PAM: Precise arthroscopic mini-trochleoplasty; MPFLR: Medial patellofemoral ligament reconstruction.

Figure 2 Preoperative and postoperative three-dimensional computed tomography images of a case of left knee recurrent patellar dislocation with type D Dejour trochlear dysplasia. A: Before surgery, a spur on the proximal side of the trochlear groove and subluxation of the patella could be seen. The black-dashed line was the plan for the new groove (a1); two days after precise arthroscopic mini-trochleoplasty (PAM trochleoplasty), the spur was removed, and two pieces of subchondral bone attached to the osteochondral flap could be seen on the new groove (black arrow). Reduction of the patella to a normal position fit for a new groove showed good patellofemoral congruence (a2); subchondral bone healing resulted in a smooth groove at 7 months after surgery (a3); bone remodeling of the groove and better patellofemoral congruence at 2 years after surgery (a4); B: Before surgery, a sagittal image illustrated the spur (white arrow) on the proximal side of the groove (b1); two days after PAM trochleoplasty, the spur and part of the trochlear bump were removed (white arrow), and subchondral bone pieces attached to the osteochondral flap could be seen (b2); bone healing of the subchondral bone formed a smooth groove at 7 months after surgery (b3); bone remodeling of the new groove at 2 years after surgery (b4). *: Lateral row anchors of suture bridge for fixation of osteochondral flap.

Figure 3 Measurement of patellar instability risk factors, lateral trochlear inclination and lateral patellar tilt. Lateral trochlear inclination was the angle between lateral trochlear facet line (blue line b) and posterior condyles line (green line a). Lateral patellar tilt was the angle between patellar axis line (orange line c) and posterior condyles line (green line a). Green dash line a’ is the parallel line of line a.