Kowaleski Treatment of XS TPA Synthes LMU 11.keyBackground
• Slocum described the TCWO (CCWO) for the treatment of the cranial cruciate ligament deficient stifle in 1984 - “Cranial tibial thrust provides
one explanation for the unsatisfactory results obtained from cranial cruciate ligament replacements or extra-articular suturing techniques”
Background
• The TPLO is a refinement of the TCWO; this procedure was described by Slocum in 1993 - The TCWO is still in
clinical use by many - Licensure - Course availability
TCWO
• Cranially based closing wedge ostectomy performed in the proximal tibia - Location?
• Distal limb is based at distal extent of tibial crest
- The wedge angle is customarily TPA - 5 degrees
TCWO
• The position of the TCWO results in cranial tibial long axis shift - This may be reduced
by placing the osteotomy as proximally as is practical, and by alignment of the cranial cortices (Bailey et al, VOS 2003)
TCWO Biomechanics
angulation of tibial crest
TCWO Biomechanics • TCWO will
undercorrect based on the biomechanics of osteotomy position
• The TCWO wedge angle needed to neutralize cranial tibial thrust is TPA plus 5º
• Ensure the TPLO is the major correction
Patella Alta
• The geometric alterations resulting from the TCWO can be advantageous when treating patella alta
• Anecdotal evidence suggests that TCWO results in greater extension of the stifle and flexion of the hock
TCWO Clinical Implications
• Tibial torsion can be corrected in conjunction with a TCWO
• The tibial tuberosity and plateau maintain their original relationship - TTT can additionally be
performed to treat MPL
TPLO/CCWO
• Utilizing the results of the previous geometric and biomechanical studies, the TPLO and TCWO can be precisely combined (TPLO/CCWO) to treat a variety of conditions
Indications
• The primary indication of TPLO/CCWO is for treatment of excessive tibial plateau angle - 2 yr, MC, 37 kg
Rottweiler - Bilateral CrCL
- Grade II/IV MPL
• Secondary to patella alta
• Significant torsional or angular malformation - 2yr, MC, 77 kg
Newfoundland - CrCL - Proximal tibial varus - Internal tibial torsion - Grade II/IV MPL
TPLO and CCWO • Slocum described the
TPLO combined with a CCWO in cases of excessive TPA - “Safe” rotation was
defined as 12 mm for the 24 mm TPLO blade
• CCWO performed with dual radial osteotomies – Calculation of a precise
wedge angle is impossible
Safe Rotation??
• The tibial plateau segment can safely be rotated until it is aligned with the patellar tendon insertion
• The tibial plateau segment acts as a buttress for the tibial tuberosity - Rotation beyond this
point eliminates the buttress effect
“safe”
on individual variation in proximal tibial anatomy, patellar tendon insertion point, osteotomy position and reduction - Low insertion, greater “safe” rotation - High insertion, less “safe” rotation
- No uniform amount of rotation • 12-mm?
• High insertion & steep TPA consider TPLO/CCWO
Low insertion point
High insertion point
Determining Safe Rotation
the osteotomy to the safe point, distance “S”
• Compare this safe distance to the amount of rotation required, distance “R”
• Consider TPLO/CCWO if distance R >>distance S
Safe (“S”)
Required (“R”)
TPLO/CCWO Planning
• 40 kg Great Pyrenees • Partial CrCL • Grade II/IV MPL
secondary to patella alta • No tibial torsion • Preoperative TPA 36.5° • Goals:
- Correct excessive TPA - Correct patella alta/MPL
TPLO/CCWO Planning
template can be used
• Measure distance D1 from the patellar tendon insertion to the osteotomy
• Measure distance D2 from the patellar tendon insertion to the osteotomy
D2
D1
TPLO/CCWO Planning
• The CCWO angle is determined considering 2 factors - Safe rotation - Amount of patella
alta correction needed
TPLO/CCWO Planning
• This case: safe rotation 12 mm - 12 mm on 30-mm TPLO
chart correlates with a preop TPA of 28°, so a CCWO of 10° was chosen
- 28 + 10 is greater than preoperative TPA of 36.5°
TPLO/CCWO Planning
• This case: safe rotation 12 mm - This will move the patella
approximately 6 mm distal which is sufficient to correct the patella alta
- The patellar translation is approximately the length of the cranial tibial cortex portion of the CCWO
TPLO/CCWO Execution
• This technique ensures accurate osteotomy placement
D1
D2 +
CCWO Planning
• The wedge can be a right triangle by design - Limbs X and Y form
a right angle
• Limb Y is parallel to and coincident with the tibial crest
• θ is the wedge angle
X
• It must intersect the TPLO at the caudal cortex
• It should form a right angle with the cranial tibial cortex 90°
TPLO/CCWO Execution
• Measure the length of the proximal limb (35 mm in this case)
• θ = 10° • Tan 10° = 0.18 • Y = 0.18 x 35 • Y = 6.3 mm • Measure 6.3 mm distal
and place a cautery mark on the cranial cortex
Y -
TPLO/CCWO Execution
-
TPLO/CCWO Execution
• Measure and mark the TPLO for a 11.25 mm rotation (26.5°) - Preop TPA + 10°
CCWO
• Apply 2 holding pins, ensure they engage the caudal cortex
TPLO/CCWO Execution
• Reduce the CCWO • Apply a k-wire from
distal to proximal to stabilize the osteotomy
• Note that the TPLO jig is not shown for clarity, but it is used
TPLO/CCWO Fixation
- #2: thru bone tunnels
TPLO/CCWO
• (2) 3/32” Steinman pins • 0.062” “holding” K-wire • (2) 16 gauge TBW • 3.5-mm TPLO plate • 7 hole narrow 3.5-mm
LC-DCP • Corticocancellous graft
applied medially & caudally
New patellar position
loosening requires implant removal
• Corticocancellous graft recommended to diminish likelihood of CCWO delayed union
Treatment of MPL • The TPLO/CCWO is
well suited to the treatment of MPL in conjunction with TPLO - Preop TPA 47° - Bilateral CrCL - Grade II/IV MPL - No tibial torsion or
femoral varus
- FVA 9°
TTT with TPLO/CCWO
• The tibial tuberosity can be lateralized by lateral translation of the tibial tuberosity segment
TTT with TPLO/CCWO
• Tibial tuberosity lateralized 5 mm
• Postop TPA 6° • Additional bone
plate required?
delayed healing) - Possible indication
be utilized to address proximal tibial angular malformation - CrCL rupture - Proximal tibial varus - Internal tibial torsion - 2yr, MC, 77
kg Newfoundland
Tibial Varus and Torsion
• Biplanar wedge CCWO - 12° correction needed - Distal jig pin bent at 12°
angle for use as a “guide pin”
- Avoid angulation of the proximal osteotomy cut, as this my interfere with the TPLO
- Instead angle the distal cut
Tibial Varus and Torsion
• Tibial torsion correction performed at CCWO – While maintaining
apposition/reduction of osteotomy surfaces
• Bilateral CrCL rupture
• Use appropriate size TBW to avoid distraction of the CCWO
• Place 2 TBWs – Avoid placing TBW
around holding pin distally
Rupture • Previous lateral
Summary
• TPLO/CCWO is a versatile procedure that can be utilized to address a number of complex conditions