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

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

3. Introduction Time consuming Validity, Reliability
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
Voir résultats de l’étude randomisée PTH vs resurfacing:
Tous les tests idem pour les deux groupes sauf hop et step

4. 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

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

6. Hop Test Modified single-leg vertical hop test (Gobbi A, 2003)
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

7. 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

8. Material and Methods Hybrid THA N = 91
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

9. Results : Hop Test in Hybride THA
Significant correlation with :
SF-36 P < 0,0001
WOMAC P < 0,0003
MAP P < 0,0008 %
56,2 %
43,8 %

10. Results : Step Test in Hybride THA
Significant correlation with :
SF-36 P < 0,0001
WOMAC P < 0,02
MAP P < 0,0008 %
49,4 %
50,6 %

11. Results
Graph Hop Test vs Womac
P = 0,008
P = 0,004

12. Results
Graph Step Test vs Womac
P = 0,012
P = 0,043

13. Results Correlation Hop vs Step = 0,804 (0,01 **) SF-36, WOMAC, MAP
No Correlation Offset MA
bearing type
age
sex

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

15. Material and Methods 54,2 yo 51,3 yo 48,9 yo 47 M (51,6%) 44 W (48,4%)
MoM Uncemented THA
N = 38
Post
MoM Resurfacing
N = 36
Post
Hybrid THA
N = 91
Ant-lat
54,2 yo
51,3 yo
48,9 yo
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
87,3
89,7
93,2
17,3
16,2
11,8
16,0
16,9
17,4
Age
Sex
Fu in Mo
SF-36
WOMAC
MAP
Hop and Step

16. Results hop test Mann-whitney
P < 0,023 MoM vs R P < 0,001 H vs Mom +R
Resurf + MoM = 6 mois results at 1 yr even better

17. Results step test

18. How explain these differences …

19. Discussion
Type of reconstruction has an effect on functional tests performance

20. Discussion: Bias Factors
hybrid
MoM THA
RSA
Offset (mm) difference operated vs non-operated
+ 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. McCaskie
Journal of Bone and Joint Surgery - British Volume,2005 Vol 87-B, Issue 2,
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) Dec;12(2):164-7

21. Discussion: Bias Factors
Head Size
Discussion: Bias Factors
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 MoM SRA
But no difference between MP and Alumina in hop and step test Alumina negative pressure as MoM

22. Discussion: Bias Factors
hybrid
MoM THA
RSA
Surgical approach
Antero-lateral
Posterior
Femoral stem
cemented
Non-cemented
No stem
Weight transfer more physiologic in RSA

23. 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

24. 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

25. 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

26. 4) Validate a subjective scale (with a motion lab)
Resurf vs MoM in gait lab
Objective and Validation of questionnaire
Correlations with other factors

27. Acknowledgments Daniel Lusignan, research nurse
Lucie Grondin, physiotherapist
David Young MD