With the increasing dissemination of joint-preserving concepts and the shift in treatment paradigms, an increasing number of patients in China are opting for high tibial osteotomy (HTO) as the preferred surgical option for managing medial compartment knee osteoarthritis. We have introduced an innovative modification of the HTO technique, in which osteotomy is performed directly at the tibial tuberosity—an area traditionally considered a contraindicated zone. Notably, the posterior segment of the osteotomy line is anatomically protected by the popliteus muscle, which shields the neurovascular structures posterior to the knee. This modification enables a transformation of the classical biplanar HTO into a uniplanar osteotomy.

Extensive anatomical studies have confirmed the safety and feasibility of performing osteotomy at the tibial tuberosity, without compromising postoperative functional recovery. Below is a detailed description of the surgical procedure.

After disinfection and draping routine, which are identical to standard HTO protocols, a skin incision is made approximately 3 cm below the medial joint line of the knee, along the posterior one-third of the medial tibial surface. The incision is directed obliquely toward the distal end of the tibial tuberosity, terminating approximately 1 cm distal and 2 cm medial to the tuberosity.

Upon dissection, the pes anserinus tendons are exposed. Approximately 1 cm distal to the pes anserinus insertion, a Kirschner wire is inserted with its tip oriented toward the fibular head to serve as the osteotomy guide pin. Intraoperative fluoroscopy is used to confirm proper positioning. A parallel guide is then used to insert a second Kirschner wire, establishing a flat reference plane for the osteotomy.

During osteotomy, care must be taken to avoid violating zones A and B of the tibial tuberosity, as defined in our previous anatomical studies (dividing the tuberosity into zones A, B, C, and D). A small oscillating saw The blade is used, positioned at approximately 15° to the horizontal plane, not exceeding 30°, to minimize risk to critical structures.

After completing the osteotomy, the medial opening is distracted according to preoperative planning. A TomoFix plate is then applied, with temporary fixation through the D hole. Fluoroscopic imaging is used to confirm optimal plate positioning.

We have termed this novel technique APTT-HTO (Anterior Popliteus Transtibial Tuberosity High Tibial Osteotomy). Through a series of clinical and anatomical studies, our team has demonstrated that APTT-HTO offers the following 11 key advantages:

1. No patella baja

2. No increase in Q-angle; thus, no lateral patellofemoral joint overload

3. Preservation of the medial collateral ligament (MCL)

4. Preservation of the pes anserinus insertion

5. Simplified and efficient uniplanar osteotomy

6. Elimination of type III hinge fracture risk

7. Complete protection of the popliteal artery by the popliteus muscle

8. Enhanced hinge compression effectiveness

9. High fluoroscopic efficiency: typically 3–5 shots; no need for lead aprons

10. Minimally invasive approach (2–3 cm incision)

11. Favorable biomechanical stability