1. Supervisor: Dr. Donna MacIntyre
The Role of Hip Abductor Strengthening in the Treatment of Patellofemoral Pain Syndrome
Presented by:
Marilyn Abel, Alyssa Hamm, Yves Leduc, Silas Wiefelspuett, Pantea Zarrinkamar
Supervisor: Dr. Donna MacIntyre

2. OVERVIEW INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION
PFPS Overview
PFPS Theory
Systematic Review Purpose
METHODS
Search Strategy
Screening Strategy
Quality Assessment
Data Analysis
RESULTS
Data Extraction
Outcomes
DISCUSSION
CONCLUSION

3. Patellofemoral Pain Syndrome (PFPS)
No universally accepted definition
Retropatellar or peripatellar pain of insidious onset in the absence of other diagnosed pathological conditions
Describes a spectrum of orthopedic abnormalities
Most common diagnosis of knee pain in active adults and adolescents
1 in 4 of total population; females > men

4. PFPS - Impact
Exacerbated by prolonged sitting & repetitive weight-bearing activities
↓ Quality Of Life
↓ Participation in exercises or sports
↑ Economic burden (medical cost, days off work, etc)

5. PFPS - Etiology Difficult to determine Considered multi-factorial
Main Current Theory:
Patellar maltracking within femoral trochlear notch caused by abnormal muscular and biomechanical forces

6. PFPS – Etiology (cont’d)
Contributing Factors:
↑ Q angle
Hypermobile patella
Patella alta
Pes planus
Weak quads
↓ Flexibility of:
Quadriceps
Hamstrings
Gastrocnemius
Iliotibial band (ITB)

7. PFPS – Etiology (cont’d)
Potential mechanisms of patellar maltracking:
1. VL tends to be stronger and/or activates prior to the VMO
Patella tracks laterally in the trochlear groove of the femur
2. Weak hip abductors
 Excessive femoral internal rotation and adduction under patella
 Relative lateral distraction of patella
 Increase patellofemoral joint stress
 Wear on articular cartilage and altered lower extremity kinematics

8. Relevant Systematic Review
Prins & Wurff, 2009
Females with patellofemoral pain syndrome have weak hip muscles: a systematic review
Review of 5 studies that measured hip strength in females with PFPS
Concluded that females with PFPS show decreased strength in hip abduction, external rotation and extension when compared to healthy controls

9. Proposed Knee Pain Mechanism
1. Weak Hip Musculature
2. Femoral Internal
Rotation/Adduction
3. Relative Lateral
Patellar Movement
4. Knee Pain

10. PFPS - Kinematics
Increased femoral internal rotation in PFPS with functional movements
Increased hip adduction angle in a prolonged run

11. Purpose of Systematic Review
Current rehabilitation of PFPS focuses mainly on knee musculature
Use of hip abductor strengthening as a treatment option needs to be investigated

12. Is hip abductor strengthening an effective component of PFPS treatment?

13. OVERVIEW INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION
PFPS Overview
PFPS Theory
Systematic Review Purpose
METHODS
Search Strategy
Screening Strategy
Quality Assessment
Data Analysis
RESULTS
Data Extraction
Outcomes
DISCUSSION
CONCLUSION

14. Operational Definition
Patellofemoral Pain Syndrome: anterior or retropatellar pain not associated with other identifiable pathological conditions

15. Search Strategy MEDLINE search
1. Patellofemoral Pain Syndrome/
2. patellofemoral pain.ti,ab.
3. knee pain.mp.
4. runner's knee.mp.
5. pfps.mp.
6. anterior knee pain.mp
7. peripatellar pain.mp
8. retropatellar pain.mp.
9. chondromalacia patella.mp
10. patellofemoral.mp
11. patellofemoral arthralgia.mp.
12. patellar pain.mp
13. patellar pain syndrome.mp
14. patellofemoral syndrome.mp
15. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14
16. physical therapy.mp
17. Rehabilitation/
18. rehabilitation.mp. 19. physiotherapy.mp. 20. exp Exercise Therapy/ or exp Exercise/ 21. Muscle Strength/ 22. strength*.mp 23. resistance training.mp 24. "Physical Therapy (Specialty)"/ or exp Physical Therapy Modalities/ 25. exp weight lifting/ or 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24 or hip abduct*.mp. 28. hip muscle*.mp or Hip Joint/ 31. Hip/ or and 29 and and 33

16. Search Flowchart

17. Search Strategy (cont’d)
Additional databases searched:
CINAHL, EMBASE, PEDro, SPORTDiscus
Grey literature searched
Google, Google Scholar, Papers First, ProQuest Dissertation and Thesis
References of selected articles were scanned
Authors in the field were contacted for additional information on unpublished data and studies

18. Screening Strategy Articles were screened by 2 reviewers
In the case of a disagreement, consensus was met through a meeting of the reviewers
Third party mediation was not needed

19. Screening Tool
Hip abductor strength as a component of Patellofemoral Pain Syndrome treatment
Article Screening Form (Adapted from Westby, MD) RefWorks ID: _________________ Screening date: ________________ Reviewer: AH, YL
Citation:________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Level of Review:
Title - Appropriate? YES _____ NO _____ (reason) __________________
Abstract - Appropriate? YES _____ NO _____ (reason) __________________
Included for full text review? YES _____ NO _____ (reason) __________________
Full Text
Article Review:
Study Design: RCT _____ CCT or Quasi-RCT _____ Crossover _____ Review _____
Case-Control _____ Cohort _____ Case Series _____
Single Subject_____ Pre-Post (no control) ____
Selection Criteria: (all 6 of the selection criteria must be met for inclusion to the systematic review)
Subjects clinically diagnosed with Patellofemoral Pain Syndrome _____
Intervention includes specific hip abductor strengthening _____
Intervention is at least 4wks in duration, minimum 2-3 days/wk _____
Comparisons are able to be drawn regarding the use of hip abductor strengthening as an effective component of treatment_____
Study uses pain and hip abductor strength as a primary outcome _____
Study is published in English, French, or German _____ 19

20. Inclusion Criteria
Uses pain and hip abductor strength as outcome measures
Comparisons are able to be drawn regarding the use of hip abductor strengthening as an effective component of treatment
Studies published in English, French or German
Subjects clinically diagnosed with PFPS
Specific hip abductor strengthening as part or whole of intervention
Intervention duration minimum 4wks, 2-3 days/wk

21. Exclusion Criteria
Subjects with recent knee injuries in addition to PFPS
Subjects with additional knee pathologies

22. Quality Assessment
PEDro Scale was used to assess quality of included studies
Process similar to that of Screening process

23. Data Analysis Data extraction tool used to collate relevant data
Independently extracted by 2 reviewers and compared for consistency
It was not necessary to contact authors for missing data

24. OVERVIEW INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION
PFPS Overview
PFPS Theory
Systematic Review Purpose
METHODS
Search Strategy
Screening Strategy
Quality Assessment
Data Analysis
RESULTS
Data Extraction
Outcomes
DISCUSSION
CONCLUSION

25. Results Search Strategy Of 182 articles screened, 3 were eligible
Articles were excluded based on:
Lack of intervention
Type of intervention
Focus on other knee pathologies (i.e. ITBS, OA, TKA, etc)
Auto alerts set up in MEDLINE, SPORTDiscus, Embase, and CINAHL
1 article was retrieved from Embase  went to full text  included in the review

26. Results (cont’d)
Mascal et al. 2003, Management of Patellofemoral Pain Targeting Hip, Pelvis and Trunk Muscle Function: 2 Case Reports
Tyler et al. 2006, The Role of Hip Muscle Function in the Treatment of Patellofemoral Pain Syndrome
Nakagawa et al. 2008, The Effect of Additional Strengthening of Hip Abductor and Lateral Rotator Muscles in Patellofemoral Pain Syndrome: a Randomized Controlled Pilot Study

27. Mascal et al. (2003) - Case study
First study to assess the role of hip musculature in PFPS treatment
Progressive hip muscle strengthening (glut max and med, hip abd, and ER):
Pain relief and improved biomechanical kinematics in a step-down exercise (decreased hip adduction and femoral internal rotation)

28. Tyler et al. (2006) - Cohort study
Strengthened hip flexors, abductors, adductors & stretched hip flexors and ITB
↑ Hip abductor strength: not significant for pain relief
Combined iliopsoas strengthening & lengthening with ITB lengthening

29. Nakagawa et al. (2008) - RCT
Quad strengthening with hip abductor and external rotation strengthening (intervention group):
↓ Pain during functional activities
Did not identify which muscle group had greater contribution
↑ hip eccentric ER and hip abd torque: not statistically significant but clinically significant
Small n & short Tx time → statistically insignificant
↑ Hip motor control → clinically significant

30. Quality Assessment: PEDro Scale

31. Results (cont’d) Common PEDro trends amongst 3 included studies:
Similar baseline groups
Measured at least one key outcome in >85% of the subjects
Provided either treatment or control condition to all of their subjects
None of the three studies blinded their therapists providing the treatment

32. Data Extraction
Studies were not similar enough to compare quantitatively
Data from studies was extracted and qualitatively compared based on PICO headings (Population, Intervention, Comparison, Outcomes)

33. Data Extraction Study Participants Intervention Comparison Outcomes
Mascal et al. (2003)
2 ♀
14 wks
Clinic: 1-2/wk & HEP: 2/day
- Glut max/med, ext rotators, core, pelvic floor
Pre/Post measures,
no control group
Muscle strength,
Pain,
Fxn’l status,
P-F jt exam, Dynamic Ax, Biomech Ax
Tyler et al. (2006)
29 ♀
6 ♂
(8 bilat, total 43 knees)
6 wks
Clinic: ~2/wk & HEP: 1/day
- Hip flexors, abductors, adductors
Muscle strength, Pain,
Flexibility,
Physical Exam
Nakagawa et al. (2008)
10 ♀
4 ♂
Clinic: 1/wk and HEP: 4/wk
- All: quads
- Intervention group: TA, hip abductors, ext rotators
Control group vs. Intervention group
EMG

34. Measurement of Hip Strength

35. Hip Strength Outcomes: % change

36. Pain Outcomes: VAS % change

37. Pain Outcomes All 3 studies used the Visual Analog Scale (VAS):
Nakagawa et al. (2008): squatting and prolonged sitting
Mascal et al. (2003): walking
Tyler et al. (2006): ADLs and exercise
All 3 looked at the presence of pain with completion of stairs
Tyler et al. (2006): climbing stairs (Y/N questionnaire)
Nakagawa et al. (2008): ascending & descending stairs (VAS)
Mascal et al. (2003): stairs in general (VAS)

38. Pain Outcomes (cont’d)
Large ↓ in pain in participants in the Mascal et al. and Nakagawa et al. studies
Tyler et al. had a ↓ in their participant’s pain but at a smaller reduction

39. OVERVIEW INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION
PFPS Overview
PFPS Theory
Systematic Review Purpose
METHODS
Search Strategy
Screening Strategy
Quality Assessment
Data Analysis
RESULTS
Data Extraction
Outcomes
DISCUSSION
CONCLUSION

40. Discussion
Aim: investigate whether patients with PFPS could benefit from hip abductor strengthening to reduce their symptoms
Conclusion: limited amount of clinical research supporting this theory presently
Further research required to clarify role of hip muscle strengthening for certain PFPS patients

41. Included Studies Similar PFPS theoretical framework:
Lack of hip control and/or weak hip musculature
 Excessive femoral internal rotation and adduction under patella
 Relative lateral distraction of patella
 Increase patellofemoral joint stress
 Wear on articular cartilage and altered lower extremity kinematics
Treatment Approach: focus on hip musculature control of femoral movement

42. Trends: Study Design
Chronological progressive improvement in quality of study design
Mascal et al. (2003) – case study
Tyler et al. (2006) – cohort study
Nakagawa et al. (2008) – RCT

43. Qualitative Assessment
Comparable outcome measures in all three studies:
1. ∆ hip abductor strength
2. ∆ pain

44. 1. ∆ Hip Abductor Strength
Hip abductor strength ↑ as a result of each treatment protocol
Mascal et al. & Nakagawa et al.
Combination of ↑ hip muscle strength (abd & ER) & motor control → improvement of L.E. kinematics
Tyler et al.
Hip abductor strengthening not clinically significant
Suggests other hip musculature reduces femoral internal rotation

45. 2. ∆ Pain Mascal et al. & Nakagawa et al. Tyler et al.
Hip abductor & external rotator strength improvements explain change in hip kinematics recorded
 pain reduction
Tyler et al.
Implicates different sets of musculature changes responsible for arriving at the same conclusion of pain reduction

46. Core & Hip Motor Control
These variables were not specifically evaluated and tabulated in any of the included articles
Possible increases in core and hip motor control may contribute to the decrease of PFPS symptoms

47. Limitations Small number of studies available
Total of 51 participants were studied:
→ limits the conclusions that can be made from the resulting data
Heterogeneity between the included articles:
→ analysis and comparison more difficult
→ may result in themes being overlooked and not identified for discussion

48. Recommendations for future studies
RCTs
Increase sample size
Longitudinal studies with short, medium and long-term follow-up periods
Exercise protocols with core strengthening and hip motor control exercise
Differentiation for hip external rotation, extension and abduction musculature

49. OVERVIEW INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION
PFPS Overview
PFPS Theory
Systematic Review Purpose
METHODS
Search Strategy
Screening Strategy
Quality Assessment
Data Analysis
RESULTS
Data Extraction
Outcomes
DISCUSSION
CONCLUSION

50. Dissemination Physiotherapy Canada
Distributed to a large population of our peers
Reach PTs across different domains

51. Conclusion
Present research does not conclusively identify the benefits of hip abductor strengthening for PFPS treatment

52. Clinical Application
PFPS patients present with unique biomechanical dysfunctions
Excessive femoral internal rotation and adduction pathology
Multiple hip muscles may be involved
Patients with insidious knee pain require thorough assessment of the hip, as well as the knee, to determine cause of pain and best course of treatment

53. Special Thanks Dr. Donna MacIntyre Charlotte Beck Dr. Darlene Reid
Dr. Elizabeth Dean

54. QUESTIONS?