An avulsion fracture occurs when a  puppy🐶 breaks a 🦴 & a fragment of the 🦴 is separated by the pull of an attaching muscle, tendon or ligament. The tibial tuberosity is the prominent bump on the front & top of the tibia, the shin-bone, below the knee  joint . This tuberosity attaches the patella (knee-cap) via a strong thick tendon of the quadriceps muscle group. A fracture of the tibial tuberosity often results in an avulsion fracture, by virtue of the pull of the quadripceps muscles. This fracture occurs in puppies before this area of the tibia has fully grown & fused to the rest of the bone. The fracture occurs in association with trauma, after often falling from a height & landing with the knee in flexion, tearing the bone fragment from its normal position. Untreated, the knee joint & consequently the limb function on the affected leg may be poor. Symptoms include: Sudden onset of hindleg lameness (non-weight bearing), Pain, Swelling around the front of the knee joint. Your veterinarian will perform an orthopedic evaluation of your pet. The 🦵 is usually painful on flexion & extension, swollen & painful on palpation over the top front portion of the tibia. The patella (knee cap) may ride higher than usual, because it is no longer firmly attached to the tibia. X-rays radiographs will confirm the diagnosis & both knees are radiographed to confirm the diagnosis as the displacement of the bone fragment can vary from small & subtle to dramatic. This type of fracture is best treated by surgery & fixing the bone back in its correct position; otherwise, the quadriceps muscle group may continue to pull the bone fragment away. Fixation is achieved under anesthesia by cutting the skin, exposing the fracture site & fixing the displaced piece of bone in position using pins & tension wire. X-rays will be taken after surgery to assess the position of the implants & the realignment of the bone. After surgery exercise should be restricted for 6 weeks.