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Hamilton Specialist Referrals offers a truly world class orthopaedic referral service

Hamilton Specialist Referrals (HSR) offers a truly world class orthopaedic referral service. As well as being Diplomates of the European College of Veterinary Surgeons (ECVS) and recognised by the European Board of Veterinary Specialisation, our surgeons are RCVS Recognised Specialists in Orthopaedics, ensuring the highest possible standards of care for your clients and their pets.

HSR has the latest technologies to assist in the diagnosis and treatment of any form of orthopaedic disease or injury. There is a 1.5T high-field magnetic resonance imaging (MRI) and computerised tomography (CT) suite on site and the hospital has invested in the latest direct digital radiography systems (also known as radiographs or X-rays) (DR). We routinely use computerised gait analysis to aid in the diagnosis of complex multi-limb lameness and employ the same technology to monitor recovery from surgery. This individual approach to post-operative rehabilitation optimises outcomes and shortens recovery times.

  • Cranial Cruciate Ligament Rupture
  • Osteoarthritis
  • Elbow Dysplasia
  • Hip Dysplasia
  • Hyperextension Injury
  • Limb Deformity Correction
  • Limb Sparing Surgery

Cranial Cruciate Ligament Rupture

Cruciate disease is one of the most common causes of pelvic limb lameness in dogs. We perform tibial plateau levelling osteotomy (TPLO) which is seen as the gold standard for the treatment of CCL rupture in small animals.

We use the highest quality poly-axial locking plates with a pure-silver based plasma coating, which provides a constant release of silver ions to inhibit bacterial growth. At the time of print we have seen almost no cases of post-operative wound infection when using these new generation implants.

Our experienced surgeons have performed several thousand TPLO procedures. As well as standard TPLO in dogs ranging from 3kg to >100kg we regularly perform:

  • TPLO with concurrent correction of patellar luxation
  • Single stage bilateral TPLO in cases with bilateral CCL rupture
  • TPLO and concurrent limb alignment correction
  • TPLO in cats



What Causes Osteoarthritis in Animals?

Osteoarthritis is an inflammation of the joints and is a common condition in dogs. It occurs when cartilage within the joint changes or becomes damaged, making it less smooth and causing the bones in the joint to rub together; resulting in pain, discomfort and stiffness. Osteoarthritis in dogs and cats is always secondary to an underlying joint disease and management of the underlying disease is important.

How to Tell If Your Pet Has Osteoarthritis?

As with most orthopaedic conditions in animals, commons signs can be detected from their movements and behaviour. If your pet is displaying a limpness/lameness and is reluctant to walk, climb stairs or play, there is a chance they are suffering from arthritis.

They may also start showing signs of aggression or licking the affected joints due to the pain.

Treatment Options

Osteoarthritis can be treated with anti-inflammatory medication, dietary management to help take weight off the affected joints, and through physiotherapy. These preventative measures will help ensure that the condition doesn’t progress to the point where surgical intervention is required.

Sadly, there is no ‘cure’ for osteoarthritis, only management. To ensure your pet has the best quality to life with this condition, it’s important to continue weight and dietary management so as no unnecessary pressure is put on the joints in question.

Elbow Dysplasia

Our surgeons at HSR perform hundreds of arthroscopic surgical procedures each year. We have the very latest in high deļ¬nition arthroscopic equipment we can offer the best surgical options for each case.

We record our procedures and are proud to show these to owners when they collect their pets. The most common cause of thoracic limb lameness is pain associated with the elbow and thus the majority of our arthroscopic caseload is elbow arthroscopy. The procedures we offer include:

  • Arthroscopic subtotal coronoid ostectomy (SCO)
  • Arthroscopic biceps ulnar release (BUR)
  • Proximal bioblique ulnar osteotomy
  • Proximal abducting ulnar osteotomy (PAUL)
  • Canine unicompartmental elbow (CUE)
  • Joint resurfacing for OCD lesions with SynACART™ grafting

Hip Dysplasia

Canine Hip Dysplasia (CHD) is a multifactorial disease that has received massive amounts of funding.

Clinical Signs

The clinical signs of hip dysplasia generally become evident to owners between 5-9 months of age. Since laxity can be measured at 4 months of age this suggests that laxity is not the sole cause of clinical signs. This gives credence to the thought that the consequences of laxity, namely, damage to the joint margins and synovitis result in the clinical signs.


Palpation tests – Ortolani Sign: This is the most widely used palpation test. This can be performed in the anaesthetised or heavily sedated patient in lateral or dorsal recumbency. The test relies on manual force to subluxate the femoral head, gradual abduction of the hip joint allows relocation of the femoral head in to the acetabulum. This relocation is palpated as a “clunk.” The clinician is required to evaluate this clunk to give some idea as to the depth of the acetabulum. There is little correlation demonstrated between Ortolani signs and radiographic signs (Puerta).

Radiographic Methods:

Traditional radiographs give little information on laxity but does allow for evaluation of the secondary changes within the joint. Extension of the hip can cause tension in the joint capsule and resultant medial displacement of the femoral head within the acetabulum creating a false impression of the joints congruence.

Tests for Laxity: 

Penn Hip -This is a technique to assess laxity on a neutral hip position, provides a numerical value to the degree of laxity termed the distraction index (DI). There is an alternative technique the dorsolateral subluxation technique (DLS) which is similarly designed to assess the degree of laxity. Evaluation of DI has highlighted breed differences in tolerance for passive laxity. In various studies DI was the strongest predictor for development of osteoarthritis. Across all breeds a DI of less than 0.3 indicates a low likelihood for development of osteoarthritis.

Treatment Options

The options for treatment of CHD depend on a number of variables such as severity of clinical signs, age, breed, weight and also the feelings of the owner. There is a study (Barr) that suggests that 75% of animals that are born with hip dysplasia will have good clinical function without the requirement for surgery. Conservative therapy is relatively uniform across the board for orthopaedic disease and consists of controlled activity such as leash walking, dietary management to provide an optimum body weight, physical therapy and judicious use of non steroidal anti-inflammatory medications when necessary. Joint supplements such as glucosamine and chondroitin are also being commonly used at this point in time based on their use in the human field.

Non-Surgical Management

Non-surgical management may allow some improvements in lameness or pain in the short term, particularly in patients with only very limited disease development, with approximately 60-80% of younger dogs showing good improvements. Four basic methods are usually recommended:

  • Body weight management
  • Exercise modification, physiotherapy and hydrotherapy
  • Anti-inflammatory / pain relief medications
  • Nutraceutical supplements

In many patients with hip dysplasia, even those as young as 7-10 months old, the cartilage damage and osteoarthritis is so severe that medical management cannot achieve a good enough quality of life and further intervention is indicated.

Surgical Treatment

Juvenile Pubic Symphsiodesis (JPS)

JPS is a relatively recent development largely pioneered at the University of Wisconsin-Madison. Clinical and research trials have shown that this technique needs to be performed between 15 and 20 weeks of age to have appropriate clinical response. This technique requires fusion of the pubic symphysis which results in rotation of the acetabulum to provide greater coverage of the femoral head. This fusion is achieved via ventral approach to the pubis and treatment with either metallic staples or most commonly electrocautery. All patients undergoing this technique should be neutered as the radiographic phenotype of these dysplastic patients will be altered. This surgery is hampered by the requirement to see these patients prior to 20 weeks of age and so is at present rarely performed in our practice.

Total Hip Replacement (THR) 

THR has revolutionised the treatment of debilitating osteoarthritis of the hip joint.

When is a Total Hip Replacement required?

When relevant orthopaedic conditions progress to the point where they’re causing an animal significant pain, despite drug and exercise management, our orthopaedic specialists may suggest a total hip replacement.

Total hip replacement has revolutionised the treatment of debilitating osteoarthritis of the hip joint. It can also be used in the management of recurrent luxations and fractures of the hip joint that can’t be reconstructed.

How to Tell If Your Pet Needs a Hip Replacement?

If your pet is running with a swing or bunny hop, it’s likely that they’re suffering from an orthopaedic condition that could result in the need for a hip replacement. Once seen by a specialist, such as Hamilton Specialist Referrals, you will be able to establish if your pet is a good candidate for this surgery.

To undergo total hip replacement surgery, your pet needs to be in good overall health with no other bone or nerve disease. They will also need to be fully grown (unless the condition is too severe to wait) to ensure they don’t outgrow the hip replacement. This typically occurs between 9 and 12 months of age, depending on the breed.

What does Hip Replacement Surgery Entail?

The hip joint is made up of a ball and socket joint, with the ball joint at the top of the thigh bone and the socket in the pelvis. This surgery removes both the ball and the socket joint, replacing them with prosthetics. Hamilton Specialist Referrals exclusively use joint replacement implants manufactured by BiomedtrixTM, who are considered the world leader in veterinary joint replacement technology.

Primarily, they use non-cemented components in larger dogs but have the ability to perform this procedure on even the smallest dog breeds, as well as cats.

Rehabilitation and Recovery from Total Hip Replacement Surgery

After the surgery is complete, your pet will likely have to stay in the hospital for between 3 to 5 days, ensuring the beginning of the healing process runs smoothly. Once your pet has been released from the hospital, the stiches from the incision will still be in for a further 10 to 14 days, so it’s important to ensure these are left alone to heal.

Once the initial healing process is complete, comprehensive/physical pain management with our rehabilitation team will be an essential part of your pets successful recovery.

Hyperextension Injury

Hyperextension refers to damage of the many, small palmar carpal ligaments and palmar fibrocartilage and usually the result of a fall or jump, however it may occur following any traumatic event. If there is no history of trauma and hyperextension and progressed slowly immune mediated joint disease or degenerative conditions of the ligaments should be considered, particularly in Shetland Sheepdogs, Rough Collies and Border Collies. The inflammatory response causes necrosis within the collagen bundles, leading to weakening of and rupture of the ligaments and tendons. Ligamentous degeneration has also been reported in middle aged cats (Miller) and in older, over-weight large breed dogs (Li). The only tendon that is of any bearing on carpal stability in extension is the flexor carpi ulnaris which inserts on the accessory carpal bone. This is not usually injured in hyperextension injury and in isolation results in only very mild hyperextension. A skin laceration or palpable pain and inflammation around the injured tendon makes the diagnosis relatively easy.

As well as being one of the most serious injuries to the canine carpus, hyperextension is also one of the most common. Affected dogs are usually non weight bearing for several days after the injury, but usually begin to bear weight within a week or so. Depending on the severity of the damage to the palmar supporting structures, obvious hyperextension of the carpus is seen during weight bearing, or during manual extension of the carpus. Comparison with the contralateral limb should be done, but the possibility of bilateral injuries should also be considered. In severe cases animals weight bear on the metacarpal pad, however the hyperextension can be subtle and should be considered in any animal with pain localised to the carpus. Pressure and abrasion sores are common sequelae. In larger breeds it may be apparent at which level the injury has occurred which can have implication with regard to future treatment.

Clinical Signs and Diagnosis

The affected carpus is usually very swollen, although unless there are concurrent fractures present manipulation of the carpus is surprisingly non-painful. Considering the anatomy, firm digital pressure should be applied to each of the carpal and metacarpal bones in turn with regard to fractures; this is particularly important in Boxers with regard to radial carpal bone fractures which are not usually fracture lame, but do have focal pain over the radial carpal bone – see radial carpal bone fracture.

Overt instability is usually fairly easy to detect on clinical examination, however orthogonal radiographs are mandatory. Careful examination for small avulsion fragments of bone should be performed as these can indicate the specific location of injury which may otherwise be missed. Soft tissue swelling should be looked for, which may also give an indication to the location of a localised injury. Oblique views should be taken as necessary to further skyline any region of interest. A series of ‘stressed’ radiographic projections should also be obtained to fully assess for concurrent injury to other ligamentous structures and to determine at which joint level the palmar instability is occurring. Minimally displaced avulsion fractures are also easily detected using this technique. These projections are obtained by ‘stressing’ the joints into valgus (to check the integrity of the medial collateral ligaments), and varus (to check the integrity of the lateral collateral ligaments) using rope ties, and taking dorsopalmar radiographs with the joints in the stressed position. Comparison of the contralateral side will help detect subtle differences. A lateral projection taken with the carpus ‘stressed’ into maximal extension will reveal at which level or levels the palmar supporting structures are injured, which is important in selecting the most appropriate treatment.

Approximately 10 – 15° of extension is present in the normal carpus, but in some dogs this can be up to 30°. Comparison with the contralateral limb is helpful indistinguishing subtle abnormality although increased weight bearing on the non injured side may increase the degree of extension. Carpal laxity is often present in puppies who seem to be somewhat ‘dropped’ in the carpal region. This is not associated with trauma and can be spectacular, but is does not require treatment and is usually self limiting - see carpal laxity syndrome. The most commonly affected joint is the carpometacarpal joint, followed by the intercarpal joint and then the antebrachiocarpal joint. The approximate frequency of injury has been reported as antebrachiocarpal 10%, intercarpal 28%, carpometacarpal 46%, combined intercarpal and carpometacarpal 16% (Brinker). This increasing frequency of injury seems logical in that the joints with the least degree of normal movement would be injured most commonly when hyper-stressed during injury, the increased movement in the other joints affording a certain degree of protection.

Careful assessment of the angular relationship of the rows of carpal bones indicated at which level the injury has occurred. In cases of intercarpal luxation there is an obvious gap between the palmar process of the ulnar carpal and metacarpal V and in cases of carpometacarpal injury, the bases of the metatarsal seem to overlap the carpal bones. Antebrachiocarpal injuries are the most difficult to detect, however small fractures are often seen off the palmar aspect of the radius, which indicates injury in this region.


Invariably, hyperextension injury requires some form of arthrodesis. Pancarpal arthrodesis involves fusion of all three joint levels, whereas partial carpal arthrodesis involves fusion of the intercarpal and carpometacarpal joints. Splinting of the limb is generally unrewarding with hyperextension as the randomly arranged scar tissue does not have sufficient strength to support the high tensile stresses placed on the palmar aspect of the carpus every time the dog bears weight. External coaptation should be reserved for acute cases of mild hyperextension injury only and if this treatment option is used, specially made orthotic devices are best (www.orthopets.com) as these are much more comfortable and allow air circulation, as well as having the option of allowing a gradually increasing degree of extension due to adjustable articulations within the device itself.

If the antebrachiocarpal joint is affected then the surgical treatment should be pancarpal arthrodesis. Likewise in chronic cases, with significant degenerative changes throughout the carpus, a poor result is likely if complete carpal fusion is not performed. Although it is technically possible to fuse the antebrachiocarpal joint in isolation this is not recommended as the increased stress on the lower joints predispose them to subsequent injury. In addition, if the antebrachiocarpal joint is injured, it is highly likely that there will also be injury to other small carpal ligaments more distally and if these are not addressed then ongoing lameness will result.

If the level of injury is at the intercarpal or carpometacarpal levels partial carpal arthrodesis should be considered. Preserving the high motion antebrachiocarpal joint will result in minimal change in gait and gives athletic animals the potential for a more complete return to function than would be possible if all three joints are fused. If partial carpal arthrodesis is to be considered owners must be warned that if lameness persists, subsequent salvage by way of pancarpal arthrodesis may be required. It is the authors experience that there are few cases of hyperextension in medium to large sized dogs that are suitable candidates for partial arthrodesis procedures and in the majority of patients pancarpal procedures are performed, particularly in cases with intercarpal injury. Partial carpal arthrodesis is more likely to be successful in small to medium sized dogs and cats, and those with apparently isolated injury to the carpometacarpal joint as there is a greater likelihood that the antebrachiocarpal joint will be unaffected.

It is imperative that the hyperextended lateral radiograph is viewed in conjunction with the valgus and varus stressed projections as complete fusion of the affected joint level may not necessarily be indicated and partial fusion of the injured side may be all that is required.

Limb Deformity Correction

Angluar limb deformities can be extremely complicated cases and in relatively straightforward cases we use a dome-shaped saw blade to produce a ‘ball and socket’ at the site of the osteotomy. This allows the limb to be realigned in multiple planes preserving good bone to bone contact which provides added stability and speeds healing.

In more complex cases, we obtain 3D CT scans of the limb and use Computer Aided Design (CAD) technology in the manufacture of case specific cutting guides to aid optimal realignment of the limb.

Limb Sparing Surgery

In some cases, lameness or sometimes fractures are related to a neoplastic process.

When appropriate we offer limb salvage by placement of custom-made endoprosthetic implants based on ultra-high definition 3-dimensional CT reconstructions.

Our Orthopaedic Team

Dr Michael Hamilton

Dr Michael Hamilton

Dr Michael Hamilton BVM&S, CertSAS, DipECVS, MRCVS EBVS Recognised Diplomat in Small Animal Surgery
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Dr David Sajik

Dr David Sajik

Dr David Sajik BVetMed MVetMed PGCert Dipl.ECVS MRCVS RCVS Recognised and European Specialist in Small Animal Surgery
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Dr Tim Easter

Dr Tim Easter

Dr Tim Easter BVMedSci BVM BVS DipECVS MRCVS EBVS Recognised Diplomat in Small Animal Surgery
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Dr Tige Witsberger

Dr Tige Witsberger

Dr Tige Witsberger DVM, MRCVS, DACVS (SA) ABVS Recognised Diplomat in Small Animal Surgery
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Hanna Kepa - Senior Orthopaedic Nurse

Hanna Kepa

Hanna Kepa RVN Senior Orthopaedic Nurse
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Shannon Brook - Orthopaedics Nurse

Shannon Brook

Shannon Brook RVN Orthopaedics Nurse
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