Functional tests for THA evaluation Hop and Step

Functional tests for THA evaluation Hop and Step tests: new functional tests for THA evaluation PA Vendittoli, MD, V Godbout , MD *, M Lavigne , MD, N Duval , MD

Functional tests for THA evaluation Introduction Assessment of clinical outcome post THA *questionnaires SF-36, WOMAC, Harris Hip Score *external observer tests step up and go, gait analysis

Functional tests for THA evaluation Introduction • Time consuming — Md and Patient • Validity, Reliability — Not well established for majority • Lack of Precision between patients with excellent results Maybe not suitable to evaluate the young and more demanding patients with THA — Not all specific to Hip —

Functional tests for THA evaluation Goals 1) Describe 2 new functional tests for post-op evaluation of patient with THA 2) Correlate results with other outcome measures 3) Determine results of “step” and “hop” tests in different group of pts 4) Validate a subjective scale (with a motion lab) for in office use

Functional tests for THA evaluation Material and Methods 1 - Describe the hop and step tests performances of a group of patient with well functioning THA N 91 Avg age Sex 54, 2 y 47 M (51, 6 %) Avg f/up Approach Component Hybrid 44 W (48, 4 %) 5, 6 y 82 antero-lateral 49 M-P 28 mm 9 posterior 42 alumina 32 mm Yes

Functional tests for THA evaluation Pre-Op Hop Test • Modified single-leg vertical hop test (Gobbi A, 2003) • Hop on one foot with no assistance • Requirements : dynamic balance, hip flexors and abductors strength, confidence • External observer and patient rates using subjective scale : — — Very easy Easy Difficult Impossible Post-Op Original test description: Dr David Young, Australia

Functional tests for THA evaluation Pre-Op Step Test • Climb and get down a two step height using one leg with no assistance • Requirements : dynamic balance, hip flexors and abductors strength, hip range of motion, confidence • External observer and patient rates : — — Very easy Easy Difficult Impossible Post-Op Original test description: Dr David Young, Australia

Functional tests for THA evaluation Material and Methods 2 - Correlate the hop and step tests performances with other outcome measures • • • SF-36 WOMAC MAP Bearing surfaces Hip reconstruction Other patients data Hybrid THA N = 91

Functional tests for THA evaluation Results : Hop Test in Hybride THA Significant correlation with : % • SF-36 • WOMAC • MAP 43, 8 % 56, 2 % P < 0, 0001 P < 0, 0003 P < 0, 0008

Functional tests for THA evaluation Results : Step Test in Hybride THA • Significant correlation with : % • SF-36 • WOMAC • MAP 49, 4 % 50, 6 % P < 0, 0001 P < 0, 02 P < 0, 0008

Functional tests for THA evaluation Results Graph Hop Test vs Womac P = 0, 008 P = 0, 004

Functional tests for THA evaluation Results Graph Step Test vs Womac P = 0, 012 P = 0, 043

Functional tests for THA evaluation Results Correlation Hop vs Step = 0, 804 (0, 01 **) SF-36, WOMAC, MAP No Correlation Offset MA bearing type age sex

Functional tests for THA evaluation Material and Methods 3 - Compare hop and step tests performances between different groups of patients Hybrid THA N = 91 Ant-lat Control group Mo. M Uncemented THA N = 38 Post Mo. M Resurfacing N = 36 Post Randomized study

Functional tests for THA evaluation Material and Methods Hybrid THA N = 91 Ant-lat Mo. M Uncemented THA N = 38 Post Mo. M Resurfacing N = 36 Post Age 54, 2 yo 51, 3 yo 48, 9 yo Sex 47 M (51, 6%) 44 W (48, 4%) 22 M (57, 4%) 16 W (42, 6%) 24 M (68, 5) 12 W (29, 6) 66 6 6 SF-36 87, 3 89, 7 93, 2 WOMAC 17, 3 16, 2 11, 8 MAP 16, 0 16, 9 17, 4 Fu in Mo Hop and Step

Functional tests for THA evaluation Results hop test Mann-whitney P < 0, 023 Mo. M vs R P < 0, 001 H vs Mom +R Resurf + Mo. M = 6 mois results at 1 yr even better

Functional tests for THA evaluation Results step test

Functional tests for THA evaluation • How explain these differences …

Functional tests for THA evaluation Discussion Type of reconstruction has an effect on functional tests performance

Functional tests for THA evaluation Discussion: Bias Factors Offset (mm) difference operated vs non-operated hybrid Mo. M THA RSA + 3, 2 +6 - 4, 9 Resurfacing are less anatomic Comparison of offset in Birmingham hip resurfacing and hybrid total hip arthroplasty J. M. Loughead, D. Chesney, J. P. Holland, A. W. Mc. Caskie Journal of Bone and Joint Surgery - British Volume, 2005 Vol 87 -B, Issue 2, 163 -166 Better offset reconstruction gives better abductor strength Total hip arthroplasty: the relationship between posterolateral reconstruction, abductor muscle strength, and femoral offset. Yamaguchi T, Naito M, Asayama I, Ishiko T. J Orthop Surg (Hong Kong). 2004 Dec; 12(2): 164 -7

Functional tests for THA evaluation Discussion: Bias Factors Head Size Negative pressure Bearing type Komistek RD , JBJS am 2002 , Hip separation MM vs MP With fluoro MP 2 mm (avg) en swing phase vs MM = no Hybrid Mo. M But no difference between MP and Alumina in hop and step test Alumina negative pressure as Mo. M SRA

Functional tests for THA evaluation Discussion: Bias Factors Surgical approach Femoral stem hybrid Mo. M THA RSA Antero-lateral Posterior cemented Non-cemented No stem Weight transfer more physiologic in RSA

Functional tests for THA evaluation Discussion: Bias Factors Is the femoral stem the problem ? New study in fall : same bearing surface and head size with different stem In gait lab

Functional tests for THA evaluation Discussion • The Hop and Step tests are simple • Correlate well with other established function scores WOMAC, SF-35, MAP • More specific, differences not explain, gives more information on patients function

Functional tests for THA evaluation Conclusion • Hop and step tests might be useful and sensitive clinical tests to quickly and easily determine the functional status of the patient in clinical setting • Further evaluation in motion laboratory will be done to determine validity, reliability and precision of these tests and better understand variables explaining the differences found

Functional tests for THA evaluation 4) Validate a subjective scale (with a motion lab) • Resurf vs Mo. M in gait lab • Objective and Validation of questionnaire • Correlations with other factors

Functional tests for THA evaluation Acknowledgments • Daniel Lusignan, research nurse • Lucie Grondin, physiotherapist • David Young MD