Hemicircular Tibial Plateau Leveling Osteotomy (hTPLO) for Dogs with Excessive Tibial Plateau Angles: A Comparative...

Area of Science:

• Veterinary Orthopedics
• Biomechanical Engineering
• Surgical Innovation

Background:

• Cranial cruciate ligament (CCL) ruptures are common in dogs, often associated with excessive tibial plateau angles (eTPAs).
• Traditional tibial plateau leveling osteotomy (TPLO) aims to correct these angles, but challenges remain, especially with eTPAs exceeding 40°.
• The need for improved surgical techniques to address eTPAs and minimize rotational complications is critical.

Purpose of the Study:

• To compare the geometric feasibility and rotational stability of a novel hemicircular tibial plateau leveling osteotomy (hTPLO) against conventional TPLO.
• To evaluate the effectiveness of hTPLO in correcting eTPAs, focusing on rotational displacement below the patellar tendon insertion (PTI).
• To assess the differences between anatomical and mechanical axes post-correction with hTPLO and TPLO.

Main Methods:

• A comparative, model-based study using ten 3D-printed bone models with eTPAs (mean 46.06°).
• hTPLO was performed using a specialized hemicircular saw blade, while TPLO used a quarter-circular blade.
• TPLO combined with cranial closing wedge osteotomy (CCWO) was also evaluated. Measurements included rotation distance from PTI and axis differences.

Main Results:

• Postoperative tibial plateau angles (TPAs) were successfully reduced to physiological ranges (< 6°) for all methods (hTPLO: 4.93°, TPLO: 4.52°, TPLO+CCWO: 4.17°).
• hTPLO exhibited significantly less rotational displacement below the PTI (0.46 mm) compared to TPLO (8.67 mm) and TPLO+CCWO (1.13 mm) (p < 0.01).
• Differences between anatomical and mechanical axes were comparable across techniques (hTPLO: 5.74°, TPLO: 6.43°, TPLO+CCWO: 5.16°).

Conclusions:

• hTPLO is geometrically feasible for correcting eTPAs and offers reduced rotational displacement of the tibial segment relative to the PTI.
• Compared to conventional TPLO and TPLO with CCWO, hTPLO shows potential for improved rotational stability in correcting eTPAs.
• Further cadaveric, biomechanical, and clinical studies are warranted to validate the safety and clinical applicability of hTPLO.