A torn cruciate ligament in a dog is a painful diagnosis with serious consequences. Left untreated, the instability in the knee joint leads to progressive cartilage breakdown, meniscus damage and severe arthritis. At Kleintierzentrum Arndt in Karlsruhe-Durlach, we treat this injury with the TPLO (Tibial Plateau Leveling Osteotomy) — a scientifically established procedure that restores lasting load-bearing capacity to the leg.
Why the Canine Knee Is Special
Unlike in humans, a cruciate ligament tear in dogs is usually not an acute sports injury but a gradual, degenerative process: over months, micro-traumas weaken the ligament until it ruptures completely during an everyday movement.
The real cause of the serious consequences lies in the geometry of the bones. A dog’s tibial plateau is steeply sloped backwards. The cranial cruciate ligament holds the thigh bone in place on this “inclined plane”. When it tears, the thigh bone slides backwards with every step. This unnatural shearing motion irritates the joint capsule and, over time, destroys the meniscus.
Healing Through Geometric Realignment
For a long time, surgeons tried to replace the torn ligament with artificial sutures. In small dogs under 10 kg this can be sufficient — but in medium-sized, heavy or very active animals these replacement ligaments often stretch or tear under the high load.
The TPLO takes a different approach: instead of replacing the ligament, we change the statics of the bone. With a precise circular cut at the top of the shin bone, the plateau is rotated until the joint surface is almost horizontal. This neutralises the inclined plane. When the dog steps down, the force is transferred directly into the bone — no cruciate ligament is needed, and the joint is stable immediately.
The decisive advantage of the TPLO: it corrects the faulty biomechanics permanently, rather than relying on the tensile strength of replacement ligaments.
For fixation we use an established titanium system. Compared with conventional stainless steel, titanium offers several benefits:
- High biocompatibility, which minimises the risk of foreign-body reactions
- Angular stability, as the screws lock firmly into the plate
- A lower infection risk thanks to the surface properties
A Focus on the Meniscus
A cruciate ligament tear rarely comes alone: in around 40 to 50 percent of dogs the inner meniscus is also damaged. If left untreated, it continues to cause pain and an audible clicking even after a successful TPLO. That is why we inspect the inside of the joint during every operation and gently remove any damaged portions.
Anaesthetic Safety and Recovery
Every TPLO is performed under modern, highly controllable inhalation anaesthesia with continuous monitoring of ECG, oxygen saturation, blood pressure and temperature. A blood test beforehand allows us to operate even on older dogs with a well-calculable risk.
After the procedure, the plate stabilises the bone mechanically, but the actual bone healing takes time. The first two weeks call for strict rest; after that — once the sutures are removed — gradual mobilisation and targeted muscle building begin, for example on an underwater treadmill. After about eight to ten weeks an X-ray check confirms the healing before your dog gradually returns to normal activity.