犬膝蓋骨脫位
滑動的膝蓋骨導致間歇性跳躍跛行。小型犬最常受影響。
Patellar luxation is one of the most common orthopedic conditions in dogs, especially small breeds. The kneecap (patella) slips out of its normal groove, causing a skipping gait or lameness. Most cases are congenital. While mild cases may be managed medically, severe luxation causes pain and arthritis and requires surgery. RVC can diagnose and manage patellar luxation. Call +853 6677 6611.
- Patellar luxation is a dislocating kneecap that slips out of its groove
- Most common in small breeds: Chihuahuas, Pomeranians, Yorkies, Maltese, Miniature Poodles
- Causes a characteristic skipping or hopping gait
- Graded 1-4 based on severity; Grades 3-4 usually need surgery
- Untreated luxation causes arthritis and cartilage damage
- Surgical correction has a high success rate and prevents arthritis progression
What is Patellar Luxation?
The patella (kneecap) normally slides up and down in a groove on the femur as the knee bends and straightens. In patellar luxation, the patella slips out of this groove, usually toward the inside of the leg (medial luxation). This causes the leg to lock up temporarily, leading to the characteristic 'skip' — the dog holds the leg up for a few steps, then snaps it back into place. It can happen in one or both knees.
Symptoms by Grade
Grade 1: Patella can be manually pushed out of the groove but returns on its own. Usually no symptoms. Grade 2: Patella luxates on its own but can be reduced manually. Intermittent skipping lameness. Grade 3: Patella is usually luxated but can be manually reduced. Frequent lameness, abnormal leg position. Grade 4: Patella is permanently luxated and cannot be reduced. Severe lameness, bow-legged appearance, significant arthritis. Grades 3 and 4 almost always require surgery.
Diagnosis
Diagnosis is based on physical examination — the vet feels the patella slip in and out of the groove. X-rays show the position of the patella and any arthritic changes. Sedation may be needed for accurate assessment in tense or painful dogs. Blood tests rule out other causes of lameness. The vet will grade the luxation (1-4) and recommend treatment based on grade, symptoms, and age.
Treatment
Grade 1-2 without symptoms: monitor, weight control, joint supplements. Grade 2 with symptoms: anti-inflammatory medications, physical therapy, and weight management. May eventually need surgery if arthritis develops. Grade 3-4: surgical correction is recommended. Procedures include: deepening the trochlear groove (trochleoplasty), tightening the joint capsule, repositioning the patellar ligament (tibial tuberosity transposition), and releasing tight tissues. Surgery has 90%+ success rate for restoring function and preventing further arthritis.
- Intermittent skipping or hopping on a hind leg
- Persistent lameness in a small-breed dog
- Kneecap that can be felt slipping in and out
- Bow-legged appearance
- Difficulty jumping or climbing stairs
- Any lameness in a puppy of a predisposed breed
RVC provides orthopedic examinations and can refer for patellar luxation surgery. Call +853 6677 6611 for an evaluation.
+853 6677 6611