Military working dogs are of great importance for human safety when used to detect narcotics, explosives, or the location of the source of arson. They also play essential roles as patrol and guard dogs. A great deal of stress is put on the musculoskeletal system of MWDs during work. Hip dysplasia and secondary osteoarthritis have been reported1 as the most common reason for euthanasia or departure from active service in MWDs.1 Dogs with radiographic evidence of HD typically are not selected for military or police work, but a few dogs with mild to moderate HD have been accepted into MWD training programs.1 Investigators in 1 study2 determined that degenerative joint disease resulting from HD did not significantly influence the number of months dogs were able to work, compared with the number of working months for nondysplastic dogs. Those authors attributed their results to the low morbidity of the degenerative joint disease for that study and advances in medical management of HD. Nevertheless, dysplastic dogs have a significantly greater risk for developing degenerative joint disease, compared with the risk for clinically normal dogs, and diseases of the skeleton are the most important problem in the MWD population.3
Because of the enormous costs associated with the training of MWDs, it is imperative to use advances in veterinary diagnostic techniques to help detect orthopedic problems as soon as possible, thereby maximizing the working life of MWDs. Kinetic and kinematic gait analyses have been used widely to describe normal and pathologic gaits in dogs. Kinetic gait analysis performed by the use of force plates is easy to perform, and the results are valid for this reproducible method.4–10 Kinetic gait analysis is used in basic and clinical research, and several studies11–16 have been published in which researchers investigated HD.
In contrast to the use of GRFs, which provide information only about the summation of forces acting on the entire limb, kinematic analysis provides information about the function of each of the joints separately. Only a few studies17,18 have described the influence of HD on joint kinematics. In one of those studies,18 investigators detected subtle but significant alterations in joint kinematics in a nonhomogeneous group of lame dogs. In that study, the affected hip joint had an increase in extension and velocity at the end of the stance phase but the stifle and tarsal joints also had alterations, compared with results for clinically sound dogs. In another study,17 investigators found additional kinematic variables (such as joint adduction) that could be used to describe clinical signs of HD.
To the authors' knowledge, no studies have been published on whether clinically sound dogs with radiographic signs of HD also have altered joint kinematics. Therefore, the objective of the study reported here was to investigate changes in joint kinematics in the hind limbs of clinically sound dogs with radiographically diagnosed borderline HD.
Military working dog
Ground reaction force
Peak vertical force
Vertical impulse force
Range of motion
JVC camcorder GR-DVL-9500/9600, JVC, Friedberg, Germany.
Treadmill especially developed for use in animals, not available commercially, University of Sports Science, Cologne, Germany.
SIMI motion, version 6.5, SIMI Reality Motion Systems, Unterschleissheim, Germany.
Microsoft Excel 5.0, Microsoft Corp, Redmond, Wash.
SPPS, version 11.5, SPSS Inc, Chicago, Ill.
PennHIP, University of Pennsylvania Hip Improvement Program, Veterinary Hospital of the University of Pennsylvania, Philadelphia, Pa.
Moore GE, Burkman KD, Carter MN, et al. Causes of death or reasons for euthanasia in military working dogs: 927 cases (1993–1996). J Am Vet Med Assoc 2001;219:209–214.
Banfield CM, Bartels JE, Hudson JA, et al. A retrospective study of canine hip dysplasia in 116 military working dogs. Part II: clinical signs and performance data. J Am Anim Hosp Assoc 1996;32:423–430.
Banfield CM, Bartels JE, Hudson JA, et al. A retrospective study of canine hip dysplasia in 116 military working dogs. Part I: angle measurements and Orthopedic Foundation for Animals (OFA) grading. J Am Anim Hosp Assoc 1996;32:413–422.
McLaughlin RM Jr, Roush JK. Effects of subject stance time and velocity on ground reaction forces in clinically normal Greyhounds at the trot. Am J Vet Res 1994;55:1666–1671.
Roush JK, McLaughlin RM Jr. Effects of subject stance time and velocity on ground reaction forces in clinically normal Greyhounds at the walk. Am J Vet Res 1994;55:1672–1676.
Budsberg SC, Jevens DJ, Brown J, et al. Evaluation of limb symmetry indices, using ground reaction forces in healthy dogs. Am J Vet Res 1993;54:1569–1574.
Rumph PF, Lander JE, Kincaid SA, et al. Ground reaction force profiles from force platform gait analyses of clinically normal mesomorphic dogs at the trot. Am J Vet Res 1994;55:756–761.
Rumph PF, Steiss JE, West MS. Interday variation in vertical ground reaction force in clinically normal Greyhounds at the trot. Am J Vet Res 1999;60:679–683.
Fanchon L, Valette JP, Sanaa M, et al. The measurement of ground reaction force in dogs trotting on a treadmill. Vet Comp Orthop Traumatol 2006;19:81–86.
Bockstahler BA, Skalicky M, Peham C, et al. Reliability of ground reaction forces measured on a treadmill system in healthy dogs. Vet J [serial online]. 2005. Available at: www.sciencedirect.com. Accessed Jan 12, 2007.
Tano CA, Cockshutt JR, Dobson H, et al. Force plate analysis of dogs with bilateral hip dysplasia treated with a unilateral triple pelvic osteotomy: a long-term review of cases. Vet Comp Orthop Traumatol 1998;11:85–93.
McLaughlin RM Jr, Miller CW, Taves CL, et al. Force plate analysis of triple pelvic osteotomy for the treatment of canine hip dysplasia. Vet Surg 1991;20:291–297.
Bolliger C, DeCamp CE, Stajich M, et al. Gait analysis of dogs with hip dysplasia treated with gold bead implantation acupuncture. Vet Comp Orthop Traumatol 2002;15:116–122.
Boutrand JP, Davoust B, Cabassu JP, et al. Gait comparison of normal versus dysplastic adult German Shepherds by use of a force plate. Rev Méd Vet 1996;147:813–818.
Kennedy S, Soderholm LV, Hamilton S, et al. Gait evaluation in hip osteoarthritic and normal dogs using a serial force plate system. Vet Comp Orthop Traumatol 2003;16:170–177.
Budsberg SC, Chambers JN, Lue SL, et al. Prospective evaluation of ground reaction forces in dogs undergoing unilateral total hip replacement. Am J Vet Res 1996;57:1781–1785.
Poy NS, DeCamp CE, Bennett RL, et al. Additional kinematic variables to describe differences in the trot between clinically normal dogs and dogs with hip dysplasia. Am J Vet Res 2000;61:974–978.
Genevois JP, Remy D, Chanoit G, et al. Detection of hip dysplasia using standard position radiographs in 43 assistance-trained dogs. Rev Méd Vet 2003;154:121–126.
Culp WTN, Kapatkin AS, Gregor TP, et al. Evaluation of the Norberg angle threshold: a comparison of Norberg angle and distraction index as measures of coxofemoral degenerative joint disease susceptibility in seven breeds of dogs. Vet Surg 2006;35:453–459.
Owen MR, Richards J, Clements DN, et al. Kinematics of the elbow and stifle joints in greyhounds during treadmill trotting— an investigation of familiarisation. Vet Comp Orthop Traumatol 2004;17:141–145.
White SC, Yack HJ, Tucker CA, et al. Comparison of vertical ground reaction forces during overground and treadmill walking. Med Sci Sports Exerc 1998;30:1537–1542.
Buchner HH, Savelberg HH, Schamhardt HC, et al. Kinematics of treadmill versus overground locomotion in horses. Vet Q 1994;16 (suppl 2):S87–S90.
Evans R, Gordon W, Conzemius M. Effect of velocity on ground reaction forces in dogs with lameness attributable to tearing of the cranial cruciate ligament. Am J Vet Res 2003;64:1479–1481.
McLaughlin RM Jr, Roush JK. Effects of increasing velocity on braking and propulsion times during force plate gait analysis in Greyhounds. Am J Vet Res 1995;56:159–161.
Riggs CM, DeCamp CE, Soutas-Little RW, et al. Effects of subject velocity on force plate-measured ground reaction forces in healthy greyhounds at the trot. Am J Vet Res 1993;54:1523–1526.
Faber M, Schamhardt H, van Weeren R, et al. Methodology and validity of assessing kinematics of the thoracolumbar vertebral column in horses on the basis of skin-fixated markers. Am J Vet Res 2001;62:301–306.
Classification Internationale.of HD in dogs by use of guidelines established by the Fédération Cynologique
|Grade||Norberg angle (°)||Description|
|A||⩾105||Femoral head and acetabulum are congruent, craniolateral rim appears sharp and slightly rounded, and jointspace is narrow and even. In excellent hip joints, the craniolateral rim encircles the femoral head slightly more in a laterocaudal direction.|
|B||⩾105||Femoral head and acetabulum are slightly incongruent.|
|100–105||Femoral head and acetabulum are congruent.|
|C||⩾100||Femoral head and acetabulum are incongruent, or there is a slightly flattened craniolateral rim; irregularities are only mild osteoarthritic changes of the cranial, dorsal, or caudal acetabular margins; and irregularities may be evident on the femoral head and neck.|
|D||>90||Obvious incongruence between femoral head and acetabulum with (as reference) subluxation and flattening of craniocaudal rim or osteoarthritic signs are evident.|
|E||⩽90||Marked dysplastic changes (eg, luxation or distinct subluxation, obvious flattening of the cranial acetabular margin, or deformation of the femoral head [mushroom shaped or flattened]) or other signs of osteoarthritis.|