Education

• Professor

• BVSc University of Bristol 1985
• MVetClinStud, The University of Sydney 1992
• PhD, University of Bristol 1990
• Membership of the Australian College of Veterinary Scientists in Small Animal Surgery 1992
• Membership of the American College of Veterinary Surgeons (Small Animal Surgery) 1995
• Membership of the European College of Veterinary Surgeons 1996
• Royal College of Veterinary Surgeons Registered Specialist in Small Animal Surgery 1996

Research

Research interests are focused on skeletal adaptation to loading, stress (fatigue) fractures, long bone fracture repair, inflammatory stifle arthritis and associated degenerative cranial cruciate rupture in dogs. The Comparative Orthopaedic Research Laboratory has several major fields of interest, all applied to the musculoskeletal system. In bone adaptation, the rodent ulna end-loading model is being used to examine mechanisms that regulate functional adaptation of the skeleton. Currently, the laboratory is particularly interested in the neural control of functional adaptation and whether plasticity may exist in this regulatory system. Our laboratory is also focused on obtaining a fundamental understanding of the inflammatory stifle arthritis/cruciate rupture arthropathy in the dog. Currently, the laboratory is particularly interested in the mechanisms that lead to activation of joint immune responses and the development of persistent stifle synovitis. Here, we expect to identify novel therapeutic targets for clinical trials of disease-modifying drugs for treatment of stifle arthritis.

Responsibilities

Small Animal Orthopaedic Surgery

Clinical Interests

Small animal orthopaedic surgery, particularly fracture repair and treatment of dogs with inflammatory stifle arthritis and degenerative cruciate rupture.

Recent Publications

Sumner JA, Markel MD, Muir P. Caudal cruciate ligament damage in dogs with cranial cruciate ligament rupture. Veterinary Surgery 2010, in press

Bleedorn JA, Greuel EN, Schaefer SL, Manley PA, Hao Z, Markel MD, Holzman G, Muir P. Synovitis in stable stifle joints of dogs with incipient cranial cruciate ligament rupture: A cross-sectional study. Veterinary Surgery 2010, in press.

Sample SJ, Behan M, Collins RJ, Wilson AP, Markel MD, Kalscheur VL, Hao Z, Muir P. Systemic effects of ulna loading in young male rats during functional adaptation. Journal of Bone and Mineral Research 2010, in press.

Muir P, Fox R, Wu Q, Baker TA, Zitzer NC, Hudson AP, Manley PA, Schaefer SL, Hao Z. Seasonal variation in detection of bacterial DNA in the knee joints of dogs with inflammatory knee arthritis and associated degenerative anterior cruciate ligament rupture. Veterinary Microbiology 2010;141:127-133.

Colopy SA, Baker TA, Muir P. Therapeutic efficacy of leflunomide for treatment of immune-mediated polyarthritis in dogs: 14 cases (2006-2008). Journal of the American Veterinary Medical Association 2010;236:312-318.

Wu, Q, Sample SJ, Baker TA, Thomas CF, Behan M, Muir P. Mechanical loading of a long bone induces plasticity in sensory input to the central nervous system. Neuroscience Letters 2009;463:254-257.

Sample SJ, Behan M, Smith L, Oldenhoff WE, Markel MD, Hao Z, Kalscheur VL, Miletic V, Muir P.  Functional adaptation to loading of a single bone is neuronally regulated and involves multiple bones.  Journal of Bone and Mineral Research 2008;23:1372-1381.

Muir P, Peterson AL, Sample SJ, Scollay MC, Markel MD, Kalscheur VL.  Exercise-induced metacarpophalangeal joint adaptation in the Thoroughbred racehorse.  Journal of Anatomy 2008;213:706-717.

Bentley VA, Sample SJ, Livesey MA, Scollay MC, Radtke CL, Kalscheur VL, Muir, P.  Morphologic changes associated with functional adaptation of the navicular bone in horses.  Journal of Anatomy 2007;211:662-672.

Muir P, Schaefer SL, Manley PA, Svaren JP, Oldenhoff WE, Hao Z.  Expression of immune response genes in the stifle joint of dogs with oligoarthritis and degenerative cranial cruciate ligament rupture.  Veterinary Immunology & Immunopathology.2007 ;119:214-221.

Barrett JG, Sample SJ, McCarthy J, Kalscheur VL, Muir P, Prokuski L.  Short-term treatment with alendronate before or after fatigue has variable effects on bone structural properties in rats.  Journal of Orthopaedic Research 2007;25:1070-1077.

Muir P, Barrett JG, Sample SJ, Prokuski LJ, McCarthy J, Vanderby Jr. R, Markel MD, Kalscheur, Hao Z.  Effect of fatigue loading and associated matrix microdamage on bone blood flow and interstitial fluid flow.  Bone 2007;40:948-956.

Muir P, Oldenhoff W, Hudson AP, Manley PA, Schaefer SL, Markel MD, Hao Z.  Detection of DNA from a range of bacterial species in the knee joints of dogs with inflammatory knee arthritis and associated degenerative anterior cruciate ligament rupture.  Microbial Pathogenesis 2007;42:47-55.

Morgan JW, Santschi EM, Zekas L, Scollay-Ward MC, Markel MD, Radtke CL, Sample SJ, Keuler NS, Muir P.  Comparison of radiography and computed tomography to evaluate metacarpo- and metatarso-phalangeal joint pathology of paired limbs of Thoroughbred racehorses sustaining a severe condylar fracture.  Veterinary Surgery 2006;35:611-617.

Danielson KC, Fitzpatrick N, Muir P, Manley PA.  Histomorphometry of fragmented medial coronoid process in the dog:  A comparison of affected and normal coronoids.  Veterinary Surgery 2006;35:501-509.

Muir P, Manley PA, Hao Z.  Collagen degradation in ruptured canine cranial cruciate ligament.  The Veterinary Journal 2006;171:121-128.

Muir P, McCarthy J, Radtke CL, Markel MD, Santschi EM, Scollay MC, Kalscheur VL.  Role of endochondral ossification of articular cartilage and adaptation of the subchondral plate in the development of fatigue microcracking of joints.  Bone 2006;38:342-349.

Muir P, Danova NA, Argyle DJ, Manley PA, Hao Z.  Collagenolytic gene expression in cranial cruciate ligament and stifle synovial fluid in dogs with cranial cruciate ligament rupture.  Veterinary Surgery 2005;34:482-490.

Muir P, Schamberger GM, Manley PA, Hao Z.  Localization of cathepsin K and tartrate-resistant acid phosphatase in synovial membrane and cranial cruciate ligament in dogs with cruciate disease.  Veterinary Surgery 2005;34:239-246.

Da Costa Gómez T, Barrett JG, Sample SJ, Radtke CL, Kalscheur VL, Lu Y, Santschi EM, Scollay MC, Markel MD, Muir P.  Up-regulation of site-specific remodeling without accumulation of microcracking and loss of osteocytes.  Bone 2005;37:16-24.

Colopy SA, Benz-Dean J, Barrett JG, Sample SJ, Lu Y, Danova NA, Kalscheur VL, Vanderby Jr. R, Markel MD, Muir P.  Response of the osteocyte syncytium adjacent to and distant from microcracks during adaptation to cyclic fatigue loading.  Bone 2004;35:881-891.

Dwyer KW, Provenzano PP, Muir P, Valhmu WB, Vanderby Jr. R.  Blockade of the sympathetic nervous system degrades ligament in a rat MCL model.  Journal of Applied Physiology 2004;96:711-718.

Radtke CL, Danova NA, Scollay MC, Santschi EM, Da Costa Gomez T, Markel MD, Muir P. Fatigue fracture of the condyles of the third metacarpal/third metatarsal bone in Thoroughbred racehorses. American Journal of Veterinary Research 2003;64:1110-1116.