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Petchell et al: An in silico comparison of a novel CORA-based cranial closing wedge ostectomy methodology with three other techniques
Veterinary Surgery 7, 2025

🔍 Key Findings

  • The CORA-based cranial closing wedge ostectomy (CCWOCORA) consistently achieved the target postoperative TPA of 5° across all tibial morphologies.
  • CCWOCORA produced significantly less variability in postoperative TPA compared to other methods (TPA range: 5.00–5.00°; p < .001).
  • Mechanical axis advancement (MAA) was precisely controlled at 3° in CCWOCORA, leading to greater surgical predictability.
  • Other techniques (e.g., CCWOTPA, CCWOTPA–5, CCWOISO) showed greater variance in TPA, MAA, and tibial length.
  • In small-breed dogs, increasing the MAA from 3° to 5° did not affect TPA outcomes, but increased proximal bone stock, improving feasibility.
  • Wedge angles and tibial length changes varied by method, but CCWOCORA maintained length better than TPA-based methods.
  • The technique allows preoperative planning of both desired MAA and TPA, enhancing predictability and customization.
  • CORA methodology enables precise geometric correction and alignment of mechanical axes, reducing reliance on trial-and-error alignment.

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← Articles

Petchell et al: An in silico comparison of a novel CORA-based cranial closing wedge ostectomy methodology with three other techniques
Veterinary Surgery 7, 2025

🔍 Key Findings

  • The CORA-based cranial closing wedge ostectomy (CCWOCORA) consistently achieved the target postoperative TPA of 5° across all tibial morphologies.
  • CCWOCORA produced significantly less variability in postoperative TPA compared to other methods (TPA range: 5.00–5.00°; p < .001).
  • Mechanical axis advancement (MAA) was precisely controlled at 3° in CCWOCORA, leading to greater surgical predictability.
  • Other techniques (e.g., CCWOTPA, CCWOTPA–5, CCWOISO) showed greater variance in TPA, MAA, and tibial length.
  • In small-breed dogs, increasing the MAA from 3° to 5° did not affect TPA outcomes, but increased proximal bone stock, improving feasibility.
  • Wedge angles and tibial length changes varied by method, but CCWOCORA maintained length better than TPA-based methods.
  • The technique allows preoperative planning of both desired MAA and TPA, enhancing predictability and customization.
  • CORA methodology enables precise geometric correction and alignment of mechanical axes, reducing reliance on trial-and-error alignment.

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Multiple Choice Questions on this study

In Petchell 2025 et al., on CORA-based CCWO, how did small-breed dogs respond to increasing MAA from 3° to 5° in CCWOCORA planning?

A. They had a higher rate of tibial shortening
B. It caused cranial tibial subluxation
C. TPAPOST accuracy was lost
D. Proximal bone stock improved without affecting TPAPOST
E. They developed valgus deformities

Answer: Proximal bone stock improved without affecting TPAPOST

Explanation: A 5° MAA allowed better feasibility in small-breed dogs without changing TPA outcomes.
In Petchell 2025 et al., on CORA-based CCWO, which parameter was defined preoperatively to enable CORA-based planning?

A. Tibial tuberosity width
B. Desired mechanical axis advancement (MAA)
C. Femoral condyle width
D. Joint line congruity
E. Fibular length

Answer: Desired mechanical axis advancement (MAA)

Explanation: MAA was preset at 3° or 5° depending on breed size, which allowed precise calculation of the CORA.
In Petchell 2025 et al., on CORA-based CCWO, what was the key advantage of the CCWOCORA method in achieving postoperative tibial plateau angle (TPAPOST)?

A. It used anatomical landmarks for freehand wedge placement
B. It minimized surgical time compared to TPLO
C. It allowed for exact prediction and achievement of TPAPOST
D. It avoided mechanical axis advancement altogether
E. It used a uniform wedge angle across all morphologies

Answer: It allowed for exact prediction and achievement of TPAPOST

Explanation: CCWOCORA achieved a precise TPAPOST of 5.00° in all cases due to preoperative geometric planning.
In Petchell 2025 et al., on CORA-based CCWO, what is the primary purpose of plotting both PMA and DMA lines in the CCWOCORA technique?

A. To locate the femoral joint line
B. To guide implant positioning
C. To calculate joint contact forces
D. To identify the center of rotation of angulation (CORA)
E. To estimate limb length discrepancy

Answer: To identify the center of rotation of angulation (CORA)

Explanation: Intersection of the PMA and DMA defines the CORA, which determines wedge geometry.
In Petchell 2025 et al., on CORA-based CCWO, which of the following methods showed the least variability in postoperative outcomes across all breeds?

A. CCWOTPA
B. CCWOISO
C. CCWOTPA-5
D. TPLO
E. CCWOCORA

Answer: CCWOCORA

Explanation: CCWOCORA had zero variance in TPAPOST (5.00° in all cases), making it the most predictable.

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