American College of Veterinary Surgeons Dr. Chris Wood BSc, DVM (Dist), MS
DACVS (Small Animal)
For veterinary teams

TPLO planning radiographs

Coordinate new planning radiographs with the surgery team. Use the positioning and calibration examples below when taking the views at your clinic.

← TPLO referral checklist

Positioning examples

Print TPLO positioning + example radiographs · sheet 1

Dr. Wood plans each TPLO in VPOP from calibrated radiographs. Positioning or calibration errors may require repeat views.

Calibration ball on EVERY radiograph.

Sedation or anaesthesia is often needed. Include a calibration marker and a left/right marker in each view.

True lateral view

Positioning Positioning sketch for a true lateral TPLO planning radiograph with calibration marker View full screen ⤢ Annotated radiograph True lateral TPLO radiograph with the calibration ball marked and the stifle and hock each flexed to about 90 degrees View full screen ⤢
  • Stifle and hock near 90 degrees.
  • Hock included; beam centred on the stifle/proximal tibia.
  • Femoral condyles/fabellae superimposed as well as possible.

Open the lateral film without annotations ↗

Orthogonal CrCd/AP view

Positioning Positioning sketch for an orthogonal TPLO planning radiograph with calibration marker View full screen ⤢ Example radiograph Example orthogonal stifle radiograph for TPLO planning with tibia and hock included and calibration marker visible View full screen ⤢
  • Limb straight with patella centred.
  • Fabellae bisected and hock/calcaneus aligned.
  • Stifle, tibia, and hock included.

Coverage and positioning comparisons

Straight hock on the front view

Use the 0° inset to check neutral alignment of the hock (tarsus) on the CrCd view.

Close-up radiograph of the hock in neutral alignment, marked 0 degreesOpen hock image ↗
Internal and external rotation on the lateral view

Internal rotation increases overlap of the fibula and tibia. External rotation increases their separation.

Seven lateral radiographs comparing tibial rotation, with landmarks and tibia-fibula overlap highlightedOpen rotation strip ↗

The red bracket marks ±10° around neutral in the teaching strip. In a cadaver study of CrCL-deficient stifles without osteoarthritis, up to 30° of tibial rotation in either direction had no clinically relevant effect on lateral tibial plateau angle (TPA) measurements. Aim for a true lateral. Check coverage and calibration separately. Buirkle et al., 2019.

Examination notes
  • Send drawer and tibial thrust findings under sedation or anaesthesia, if available.
  • Negative or equivocal awake drawer/thrust does not rule out CCL disease; a painful or guarded dog may need re-examination.
Discuss with the owner
  • TPLO may be an option for a painful, unstable knee caused by cranial cruciate ligament (CCL) disease. It changes how the knee bears weight rather than replacing the ligament.
  • The surgical plan is confirmed after specialist examination and imaging review.
  • A meniscal click supports suspected injury; no click does not rule out a tear.
  • Coordinate calibrated planning radiographs and current pre-op bloodwork before surgery. Confirm the expected hospital stay with the surgical team.
  • For both knees, discuss combined versus staged surgery, hospital stay and home support.