Growing Pains: Forelimb Lameness in the Young Dog
Jennifer MacLeod, VMD, DACVS
Veterinary Specialty & Emergency Center
Huck, a 5-month-old male intact German Shepherd dog presented for a weight bearing left forelimb lameness of 3-4 days duration. The lameness had an acute onset and had been consistent.
Forelimb lameness cases can be challenging to diagnose and difficult to treat. A diagnostic workup for forelimb lameness often requires multiple tests, and treatment often entails long periods of rest and exercise restriction.
When presented with a young dog with forelimb lameness, the list of differential diagnoses narrows.
Primary differentials for young dog lameness include:
- Inflammatory diseases such as panosteitis or hypertrophic osteodystrophy (HOD)
- Developmental diseases such as elbow dysplasia or osteochondrosis dessicans (OCD)
- Trauma (fracture or soft tissue injury)
The work up for any patient presenting for lameness begins with a good history. A complete history includes:
- Presenting complaint. Which leg is the dog lame on? Do the owners agree? Do they mean their right or the dog’s right? Have the owner point to the leg having the problem. Is it always the same leg?
- Onset and duration of the problem. When was this first noticed? Was it an acute or gradual onset?
- Progression. Has the problem worsened or improved? Has it been static? Does it improve or worsen with time/use? It can also be helpful to ask how the dog is today, in the room, as compared to how it is at home. Many dogs have only mild to no lameness noted in the hospital but are very lame at home.
- Concurrent diseases. How is the patient otherwise? Are there any systemic signs such as inappetance or lethargy?
- Medications the patient has been on, and has there been a response to these therapies?
The next step in the work up is a thorough lameness examination. Watching the patient walk at various speeds, when turning, and even up and down inclines or stairs can be helpful. With a forelimb lameness they will often be “down on the sound” limb as they weight bear more fully on the leg that is not painful. Make sure to palpate all long bones with direct palpation and put all joints through range of motion. It is important to put each joint through extremes of range of motion as discomfort is more likely to be elicited at the extremes of flexion and extension.
Moving forward with diagnostics, radiographs are often our first test. Sedation for properly positioned radiographs is often necessary. Sedation can also be helpful in palpating the patient more thoroughly (especially in a wiggly puppy!).
On physical examination, Buck was found to have a weight bearing lameness of the left forelimb. He was painful on direct palpation over the humerus on the left. He was then sedated for radiographs.
Fig. 1-Radiograph of the left forelimb showing increased
medullary opacity of the left humerus.
Buck was diagnosed with panosteitis. Panosteitis is disease of large and giant breed dogs. It occurs most commonly between the ages of 5 and 18 months although has been reported up to 5 years. Single or multiple limbs may be affected, however, it rarely affects the same leg twice.
Patients generally present with a weight bearing or shifting leg lameness. Lameness is not typically influenced by exercise or rest. The cause of panosteitis is not known, although many factors have been implicated including genetics, viral and autoimmune factors.
The diagnosis of panosteitis is made radiographically.
Radiographic signs include increased intramedullary opacity, endosteal thickening, and periosteal new bone formation. It is important to remember that radiographs may be normal early on so, if your suspicion of panosteitis is high and radiographs are normal, repeating radiographs in 7-10 days may be helpful to confirm the diagnosis.
Treatment of panosteitis consists of pain management and exercise restriction during painful episodes. NSAIDs are the mainstay of pain management, although opioids such as tramadol can also be added. The prognosis is generally good for panostitis, although animals can have multiple bouts.
The other main differential for primary inflammatory diseases in young dogs is HOD (hypertrophic osteodystrophy). HOD is also a disease of large or giant breed dogs, although they are typically younger, presenting between 3 and 5 months of age. Patients with HOD are generally more systemically affected and can be depressed, reluctant to walk and febrile. Patients are typically swollen at the metaphyseal region and painful on palpation of this area.
The cause of HOD is also unknown, although diet and viral etiologies have been implicated. The diagnosis of HOD is also made on radiographs.
Figure 2: Radiographic signs of HOD with irregular radiolucent line and widening of the physis.
Figure 3: Progression of HOD with periosteal new bone formation bridging the physis.
Treatment for HOD also consists of pain management and exercise restriction, however, some more severe cases may need systemic support or hospitalization. In rare cases, owners may elect for euthanasia. The prognosis for mild cases is generally good, however, owners must be counseled that some patients may develop angular limb deformities and require corrective surgery.
In conclusion, the cause of forelimb lameness can be difficult to diagnose. When presented with a young dog with a forelimb lameness, history can be very important to guide differential diagnosis list. Radiographs are often the first line of diagnostics to consider, remembering that these may be normal initially but can help rule out other causes of lameness such as fractures, OCD and elbow dysplasia. Also remember that patients can have concurrent disease processes (such as elbow dysplasia and panosteitis).
Any questions or confusing cases, remember VSEC surgeons are always here to help!
Dr. Jennifer MacLeod is a board-certified veterinary surgeon at the Veterinary Specialty & Emergency Center. The Veterinary Specialty & Emergency Center operates state-of the-art emergency and specialty veterinary hospitals that are open 24/7/365 in Levittown PA, Philadelphia PA and Conshohocken PA. For more information about our world-class emergency and specialty care, please visit VSEC on the web at www.VSECVET.com.