Crooked front legs in puppies: angular limb deformity

Overview

An angular limb deformity means the bones in the leg are aligned abnormally. It most often affects the radius and ulna in the front leg. These parallel bones extend from the elbow to the wrist.

A growth disorder can make a leg curve, twist or remain shorter than usual. A typical front leg growth disorder in Dachshunds is premature closure of the growth plate at the lower end of the ulna. Mild bending may go unnoticed because a dog does not always show symptoms.

In elbow incongruity, the joint's components do not fit evenly together. Incongruity is one form of developmental elbow disease, while elbow dysplasia includes several developmental disorders.

Causes

Long bones grow in length at their cartilaginous growth plates. Growth stops when these plates close and become bone. If only one forearm bone stops growing, growth of the other creates forces that distort the limb.

A growth plate can be damaged in an accident while a puppy is growing. The shape of the lower ulnar growth plate makes it particularly vulnerable. Complete damage to a plate can stop bone growth. Partial damage can instead make the bone grow asymmetrically.

The lower ulnar growth plate is estimated to account for 80%, or 85–100%, of the bone's total growth.

In short-legged breeds, growth in bone length is genetically altered before birth. Their bones are generally shorter, thicker and more curved than those of other dogs. In Dachshunds, premature growth plate closure often occurs without a preceding accident.

Risk factors

Changes in front leg alignment are often noticed in growing dogs aged 5–12 months. The problem occurs particularly in small and medium-sized dogs. However, a dog of any size can develop it.

Most dogs grow rapidly at around 4–6 months of age. Growth usually slows at about 9–10 months. Large dogs generally reach skeletal maturity later than small dogs.

Short-legged breeds include Dachshunds, Corgis and Skye Terriers, for example. They have an inherited tendency towards premature growth plate closure. The precise inheritance mechanism in Dachshunds is unknown.

Typical symptoms

A growth disorder may show in leg alignment or movement:

• A front leg becomes clearly bowed or C-shaped.

• The toes point noticeably outwards or inwards relative to the rest of the leg.

• One front leg looks shorter than the other.

• Your dog starts limping on a front leg after play.

• Your dog moves stiffly and is less willing to run or jump.

• Claws wear unevenly or a paw rubs along the ground when walking.

• Your dog is sore when the elbow or wrist is touched and examined.

Severe deformity may make weight-bearing difficult. Movement in adjacent joints may become restricted and painful.

Complications and consequences

Abnormal alignment loads joints and ligaments unevenly. Osteoarthritis may develop. The elbow or wrist may partially dislocate. Lameness in an older dog may come from osteoarthritis in a joint deformed during puppyhood.

The long-term outlook depends on how straight the leg remains once growth ends. Existing osteoarthritis also affects later function. The outlook is generally good if deformity is not severe.

A follow-up study of severe deformities corrected with individual 3D guides included 15 dogs and 20 operated legs. Owners rated function as fully restored in 19/20 legs at an average of 23 months. Follow-up ranged from 12–43 months.

Diagnosis at the vet

The vet assesses gait and alignment of the whole limb. Joint mobility is checked. Shoulder pain is assessed alongside the elbow and wrist.

X-rays are usually taken from 2 directions to measure the location and direction of bending. Images look for bone deformity and prematurely closed growth plates. A growth plate that looks normal and open may nevertheless be damaged and no longer functioning.

CT helps assess simultaneous bending and twisting in particular. Three-dimensional images can be used to make individual bone models and surgical guides. Abnormal leg posture may also result from lax or tight ligaments or tendons.

An official incongruity screening scheme

Under some official screening schemes, elbow incongruity X-rays can be taken from 12 months of age. Both elbows are imaged at the same visit. The dog is sedated for imaging. The image must include the whole forearm as well as the elbow.

In such a classification, INC0 means a normal, narrow, even joint space without osteoarthritis. INC1 means mild incongruity. INC2 is moderate incongruity. INC3 is severe incongruity. The worse elbow determines the dog's overall official result.

Official INC assessments under this scheme are issued only for specifically designated breeds. The method is intended particularly for short-legged breeds for which a conventional elbow dysplasia assessment is not suitable as it stands. The elbow angle in the imaging position must be at least 90 degrees.

In mild INC1, there may be a small step between joint surfaces or a gap of no more than 2 mm between the humerus and ulna. INC2 includes a 2–3 mm gap between the humerus and ulna. Severe INC3 may be based on a gap of at least 3 mm or another clear joint deformity.

A joint that cannot be assessed because of an accident is marked as having no assessment when the required injury records are supplied. The official overall result then relies on the other joint alone. Routine official repeat imaging under this scheme is possible no sooner than 12 months after the previous examination.

Treatment

Mild, symmetrical and painless deformity can sometimes be managed without surgery. Weight management reduces joint loading. Conservative care may include gentle exercise and supervised rehabilitation. The vet selects pain relief according to your dog's needs.

Releasing growth and straightening bones

In a growing puppy, cutting the ulna can free the radius to grow without restraint from an overly short ulna. Remaining skeletal growth affects the choice of surgery. Osteotomy means a planned cut through a bone. Ostectomy removes a defined section of bone.

A painful or clearly crooked leg may need corrective bone surgery. The straightened bone is usually secured with a plate and screws. Some corrections may use an external fixation device.

Distal ulnar ostectomy alone was studied in 23 young dogs undergoing 31 operations. They were 4–10.8 months old. Their lower radial growth plates were still open at surgery. Severely twisted limbs were excluded from follow-up of this procedure. Lameness resolved in 20/31 legs, or 64.5% of operated legs. It improved in a further 4/31 legs, or 12.9%.

Lameness did not improve in 7/31 legs, or 22.6% of operated legs. Osteoarthritis was found in 4 of those legs with unchanged lameness.

After distal ulnar ostectomy, leg deformity did not worsen significantly. However, existing bone angles did not improve significantly during about 8 weeks of follow-up. Elbow congruity improved in 12/16 legs, or 75%, that originally had a step greater than 2 mm.

Recovery and possible further procedures

Strict activity restriction is needed initially. Exercise is increased under supervision over about 8–12 weeks. Follow-up X-rays check bone healing and fixation material position. Supervised rehabilitation supports the return of strength and normal walking.

The first postoperative review of legs corrected with individual guides took place after an average of 6.8 weeks. These first reviews ranged from 4–11 weeks.

Bone healing may be delayed or remain incomplete after surgery. Metal fixation devices can bend, break or loosen. Deformity may recur in a growing puppy and require another operation.

Complications after distal ulnar ostectomy occurred in 10/31 legs, or 32.3%. Of these complications, 8 involved the bandage. In 20 legs corrected with individual 3D guides, surgical site infection occurred in 3 legs, or 15%. Implant-related soft tissue irritation occurred in 4/20 legs, or 20%. Overall, major complications occurred in 35% of legs in this corrective surgery group. Treating these major complications involved removing fixation material.

Prevention

Breeding choices can reduce inherited susceptibility to premature growth plate closure in short-legged dogs. Elbow X-rays gather information to help control inherited front leg growth disorders.

Some breed-club guidance advises against breeding from a Dachshund with premature growth plate closure. It also advises against combining lines known to have this disorder. Dogs producing several affected offspring are also recommended to be excluded from breeding.

Under some official assessment schemes, an elbow operated on for incongruity is recorded as operated. For breeding purposes, this is treated as equivalent to the worst grade.

Important for dog owners

Do not ignore a puppy's lameness simply because it seems mild at first. Early assessment may make correction easier.

Record when leg alignment began changing and when your dog is lame. Bring details of previous injuries. Ask whether the aim is to release growth or straighten an existing deformity.

Prevent jumping after surgery. Keep your dog on a lead outdoors, including toilet trips. A protective collar can prevent wound licking.

Keep the surgical report and X-ray results for any official assessment.

The vet taking images for an official assessment scheme must be told about surgery affecting the elbow.

Frequently asked questions

Do all crooked front legs in puppies mean a bone growth disorder?

Lax or tight tendons or ligaments may also cause abnormal posture. X-rays investigate bone growth disorders. The vet also examines joint movement and pain on handling. CT can assess bone twisting before surgical planning.

Can a puppy grow out of crooked legs?

Mild, painless deformity can sometimes be monitored without surgery. Releasing the ulna in a growing puppy may prevent further bending. However, it may not straighten an existing radial deformity. A painful or significantly crooked limb may therefore need separate corrective surgery.

Should I wait until the official screening age before seeking an examination?

Some official incongruity assessment schemes require a minimum age of 12 months. However, symptoms often occur at 5–12 months. Early clinical assessment of a symptomatic puppy helps establish correction options. The vet considers remaining growth when choosing a surgical approach.

How long does recovery from surgery take?

Activity is usually restored gradually over about 8–12 weeks. Follow-up X-rays monitor bone healing. Aftercare depends on the operation performed. Supervised rehabilitation helps restore strength and movement. Jumping must be prevented while the leg heals after surgery.

Can the deformity recur after surgery?

In a growing puppy, deformity may return and need another correction. The final leg alignment after growth ends affects the long-term outcome. Osteoarthritis resulting from the growth disorder also affects the outlook. Further surgery may also be needed if fixation material breaks or loosens.