Table 4 Description of the studies and pre- post-intervention values

SG

CG

SG

CG

Bennell et al

Sample size (n = 89)

Strengthening Group (SG) (n = 45) Control Group (CG) (n = 44)

Mean age of the SG group- 64.5 (9.1)

Mean age of the CG group- 64.6 (7.6)

Kellgran Lawrence (KL) grade 2 and above were included.

A 3-dimensional gait analysis to identify the knee adduction moment.11-point NPRS Maximal isometric strength of hip musculature Step test and timed stair ascent and descent task

Hip abductor and adductor strengthening alone improved pain, function, and hip strength but did not alter knee adduction when compared with no treatment.

KAM

VAS

WOMAC function

Step test

Timed stair task

Hip abduction torque

3.2 ± 1.0

4.3 ± 2.0

24.8 ± 10.9

16.2 ± 3.7

8.0 ± 2.7

0.9 ± 0.3

2.9 ± 0.9

4.1 ± 2.5

23.7 ± 11.8

16 ± 2.9

8.2 ± 2.3

0.8 ± 0.3

3.3 ± 0.9

2.6 ± 2.1

16.2 ± 11.7

18 ± 4.3

7.0 ± 2.2

1.0 ± 0.3

2.9 ± 0.9

3.9 ± 2.6

21.9 ± 11.0

16.9 ± 2.8

7.9 ± 1.8

0.9 ± 0.3

Jorge et al

Sample size (n = 60)

Strengthening Group (SG) (n = 29)

Control Group (CG) (n = 31)

Mean age of the SG group-61.7 ± 6.4

Mean age of the CG group-59.9 ± 7.5

Kellgran Lawrence (KL) grade 1-4 were included

Pain (VAS scale)

Physical Function (WOMAC)

Walking Distance – 6MWT

Strength – 1RM

Quality of life – SF-36

Lower extremity progressive resistance exercise (inclusive of hip abductor and adductor strengthening) is effective when compared with a waitlist no treatment control group

VAS

WOMAC function

SF 36

6MWT

7.0 ± 1.3

27.7 ± 9.3 39.3 ± 16.

357.1 ± 56.9

7.0 .0 ± 1.2

28.4 ± 10.6

32.4 ± 16.0

330.2 ± 55.9

4.3 ± 3.1

17.3 ± 12.4

49.8 ± 21.9

69.5 ± 60.8

6.6 ± 1.5

26.7 ± 10.2

30.8 ± 16.8

343.1 ± 54.7

Singh et al

Sample size (n = 30)

Strengthening Group (SG) (n = 15)

Control Group (CG) (n = 15)

Mean age of the SG group- 55.33 ± 3.99

Mean age of the CG group- 54.86 ± 4.35

Kellgran Lawrence (KL) grades 2 and 3 were included.

Hip abductor strength by modified sphygmomanometer

Physical Function (WOMAC)

Walking Distance – 6MWT

Hip abductor strengthening and quadriceps exercise, when compared with quadriceps exercise alone, produced superior outcomes on function and walking distance.

WOMAC function

6MWT

Hip Strength

116.13 ± 16.01

280.13 ± 28.27

97.30 ± 9.42

113.93 ± 16.40

279.11 ± 49.23

95.47 ± 18.10

59.46 ± 12.44

378.37 ± 27.81

124.70 ± 9.45

82.73 ± 13.96

320.07 ± 46.40

96.56 ± 18.45

Yuenyongviwat et al

Sample size (n = 97)

Strengthening Group (SG) (n = 42)

Control Group (CG) (n = 44)

Mean age of the SG group- 62.8 ± 6.80

Mean age of the CG group- 62.5 ± 8.4

Kellgran Lawrence (KL) grades 2 and 3 were included.

Knee Injury and Osteoarthritis Outcome Scores (KOOS)

All KOOS subscales were significantly improved in both groups after 10 weeks. No significant difference in the scores between either group at 2–10 weeks after treatment. Nevertheless, the effects of exercise for pain, symptoms, function in daily living and knee related quality of life were found to have faster improvement within the hip abduction exercise group compared to the control group

KOOS

Pain

Symptoms

ADL

Sports and Recreation

Quality of Life

70

76

77

29

48

74

80

81

32

50

89

90

92

47

72

91

89

95

55

77

Wang et al

Sample size (n = 82)

Strengthening Group (SG) (n = 41)

Control Group (CG) (n = 41)

Mean age of the SG group- 58.4(5.3)

Mean age of the CG group- 59.2(6.1)

Kellgran Lawrence (KL) grades of 2 and above were included on the study

Pain (VAS Scale)

Physical Function

(WOMAC)

Strength was assessed by an Isokinetic Dynamometer Five Times Sit-to-Stand Test, stair ascent/descent task and Figure of 8 walk test.

Hip abductor strengthening and quadriceps exercises, when compared experimental group had superior outcomes in stair ascent/descent task, figure of 8 Walk test, and pain; but not in the Five Times Sit-to-Stand Test and Self-reported functional difficulties score

VAS

WOMAC

Fig. of 8 walk test

FTSST

Strength of hip Abduction

Stair Ascent and Descent

5.70 ± 1.00

33.8 ± 9.9

10.92 ± 2.23

15.53 ± 3.95

1.16 ± 0.33

21.05 ± 3.96

5.50 ± 0.93

32.3 ± 7.5

10.47 ± 1.38

15.49 ± 2.60

1.16 ± 0.33

20.55 ± 2.59

3.12 ± 0.83

20.9 ± 6.0

8.58 ± 1.42

3.51 ± 3.77

1.31 ± 0.36

17.10 ± 3.23

3.54 ± 1.08

26.8 ± 5.9

75 ± 1.25

13.98 ± 2.69

1.18 ± 0.37

19.35 ± 2.83

Chaudhary Ashok

Sample size (n = 30)

Strengthening Group (SG) (n = 15)

Control Group (CG) (n = 15)

Mean age of the SG group- 51.33(5.2326)

Mean age of the CG group- 52(5.0142)

Kellgren-Lawrence radiographic grade I, II and III were included in the study

Pain (VAS)

Physical function (WOMAC)

Hip abductor muscle strengthening exercises showed overall improvement in pain and physical function and is a useful adjunct exercise therapy in treating patients with unilateral medial compartment knee osteoarthritis

VAS

WOMAC

7 ± 1.690

66.66 ± 6.986

2 ± 1.463

27.66 ± 4.237

6.93 ± 1.387

67.13 ± 6.577

4.066 ± 1.907

37.46 ± 6.356

Elizabeth A. Sled

Sample Size (n = 40)

Strengthening Group (SG) (n = 20)

Control Group (CG) (n = 20)

Mean age of the SG group- 62.98 (9.73)

Mean age of the CG group- 62.98 (9.73)

Kellgren-Lawrence radiographic grading was included.

Five-Times-Sit-To-Stand test

WOMAC

Hip abductor strengthening did not reduce knee joint loading but did improve function and reduce pain in a group with medial knee OA.

Five-Times-Sit-To-Stand test

WOMAC

15.2 (12.6–17.9)

19.60 (15.95–23.25)

12.5 (10.6–14.4)

18.15 (14.19–22.11)

10.1 (9.2–11.0)

1.2 (0.25–2.15)

9.3 (8.4–10.2)

1.24 (0.00–2.46)