Variability associated with assessing changes in position of a canine uncemented femoral stem prosthesis

Summary

Objective: Evaluate variability associated with assessing changes in the position of uncemented femoral stems.

Methods: Stem level, canal fill, stem angle, and version angle were measured on craniocaudal horizontal beam (CCHB) and open leg lateral (OLL) radiographic projections of the femur of 20 dogs that had uncemented total hip replacement. Intraobserver and inter -observer repeatability were determined on immediate postoperative (PO) images. Differences in position were calculated between the first (3 months – R₁) and second (6 months – R₂) re-evaluation (R₁-R₂) time points, and between PO and R₁.

Results: The measurement process was very repeatable. For R₁-R₂, the stem appeared to subside 0.8 ± 1.4 mm for measurements based on the greater trochanter on the CCHB images, but there was a wide range (-3.9 to 2 mm; positive values indicate proximad movement). Measurements based on the inter-trochanteric crest on the OLL images had the same mean, and also a wide range (-4.4 to 2.1 mm; negative values indicate proximad movement). For PO-R₁, the stem appeared to subside 1.8 ± 2.0 mm (CCHB, based on the greater trochanter, range -7.7 to 2.2 mm), 1.6 ± 1.5 mm (CCHB, based on the intertrochanteric crest, range -0.7 to 4.3 mm); and 2.1 ± 2.1 mm (OLL, based on the intertrochanteric crest, range -1.6 to 6.8 mm).

Conclusion: The position of a stable stem can appear different on subsequent re-evaluations, but this may be due to variability associated with inconsistency of positioning of the patient and limb.

Clinical significance: Documenting subsidence in individual patients should not rely on calculations based on a single measurement.

Keywords

Uncemented total hip replacement - stem level - variability - measurements

• References

• 1 Bergh MS, Budsberg SC. A systematic review of the literature describing the efficacy of surgical treatments for canine hip dysplasia (1948-2012). Vet Surg 2014; 43: 501-506.
• 2 Marcellin-Little DJ, De Young BA, Doyens DH. et al. Canine uncemented porous-coated anatomic total hip arthroplasty: Results of a long-term prospective evaluation of 50 consecutive cases. Vet Surg 1999; 28: 10-20.
• 3 Pernell RT, Gross RS, Milton JL. et al. Femoral strain distribution and subsidence after physiological loading of a cementless canine femoral prosthesis: the effects of implant orientation, canal fill, and implant fit. Vet Surg 1994; 23: 503-518.
• 4 Lascelles BD, Freire M, Roe SC. et al. Evaluation of functional outcome after BFX total hip replacement using a pressure sensitive walkway. Vet Surg 2010; 39: 71-77.
• 5 Gondi G, Roberson JR, Ganey TM. et al. Impingement after total hip arthroplasty related to prosthetic component selection and range of motion. J South Orthop Assoc 1997; 6: 266-272.
• 6 Jasty M, Bragdon C, Burke D. et al. In vivo skeletal responses to porous-surfaced implants subjected to small induced motions. J Bone Joint Surg Am 1997; 79: 707-714.
• 7 Aspenberg P, Goodman S, Toksvig-Larsen S. et al. Intermittent micromotion inhibits bone ingrowth. Acta Orthop 1992; 63: 141-145.
• 8 Overgaard S, Lind M, Glerup H. et al. Porous-coated versus grit-blasted surface texture of hydroxyapatite-coated implants during controlled micromotion: Mechanical and histomorphometric results. J Arthrop 1998; 13: 449-458.
• 9 Schutz U, Decking J, Decking R. et al. Assessment of femoral component migration in total hip arthroplasty: digital measurements compared to RSA. Acta Orthop Belg 2005; 71: 65-75.
• 10 Valstar ER, Gill R, Ryd L. et al. Guidelines for standardization of radiostereometry (RSA) of implants. Acta Orthop 2005; 76: 563-572.
• 11 Kärrholm J, Herberts P, Hultmark P. et al. Radiostereometry of hip prostheses. Review of methodology and clinical results. Clin Orthop Relat Res 1997; 94-110.
• 12 Phillips NJ, Stockley I, Wilkinson JM. Direct plain radiographic methods versus EBRA-Digital for measuring implant migration after total hip arthroplasty. J Arthrop 2002; 17: 917-925.
• 13 Fitzpatrick N, Law AY, Bielecki M. et al. Cementless total hip replacement in 20 juveniles using BFX™ arthroplasty. Vet Surg 2014; 43: 715-725.
• 14 Iwata D, Broun HC, Black AP. et al. Total hip arthroplasty outcomes assessment using functional and radiographic scores to compare canine systems. Vet Comp Orthop Traumatol 2008; 21: 221-230.
• 15 Mostafa AA, Drüen S, Nolte I. et al. Radiographic evaluation of early periprosthetic femoral bone contrast and prosthetic stem alignment after uncemented and cemented total hip replacement in dogs. Vet Surg 2012; 41: 69-77.
• 16 Peck J, Liska W, DeYoung D. et al. Clinical application of total hip replacement.. In: Peck J, Marcellin-Little D.. editors. Advances in Small Animal Total Joint Replacement Ames, IA: Wiley-Blackwell; 2013: 69-107.
• 17 DeYoung DJ, Schiller RA. Radiographic criteria for evaluation of uncemented total hip replacement in dogs. Vet Surg 1992; 21: 88-98.
• 18 Montavon PM, Hohn RB, Olmstead ML. et al. Inclination and anteversion angles of the femoral head and neck in the dog evaluation of a standard method of measurement. Vet Surg 1985; 14: 277-282.
• 19 Quinnipiac University Political Science Department. Information page - Pearson's r Correlation (modified from Instructor's Resource Guide for the Text)[Website page]. Quinnipiac University; copyright 2008-2015 [Cited 2013 March 10] Available from: http://faculty.quinnipiac.edu/libarts/polsci/statistics.html
• 20 McCalden RW, Naudie DN, Thompson A. et al. RSA analysis of early migration of the uncemented SMF vs SYNERGY stem: A prospective randomized controlled trial. Bone J Sci 2011; 1: 1-6.
• 21 Ayers D, Hayes P, Eskander M. et al. Early micromotion of a tapered femoral stem in cementless total hip replacements (THR) in young patients.. Proceedings of the 55th Annual Meeting of the Orthopaedic Research Society 2009. February 22-25 Las Vegas, NV, USA: Poster no 2047
• 22 Bausman JA, Wendelburg KL. Femoral prosthesis version angle calculation from a sagittal plane radiographic projection of the femur. Vet Surg 2013; 42: 398-405.
• 23 Maguire P, Siclari M, Lesser A. Femoral imaging artifacts associated with dorsal recumbency craniocaudal radiographic positioning. Description of a modified bisecting angle technique. Vet Comp Orthop Traumatol 2014; 27: 288-296.