Knee osteoarthritis (OA) is a chronic problem affecting a significant proportion of older people and is a major cause of pain and disability. Muscle weakness, particularly of the quadriceps, is one of the earliest clinical signs of knee OA and has long been recognized as a hallmark of the disease. In fact, muscle weakness may precede disease onset and play a role in knee OA pathogenesis. Since muscle strengthening improves pain and function in knee OA, strengthening exercise is widely recommended for the condition. However, most research has focused on the role of quadriceps strength in knee OA, with little attention given to other lower extremity musculature. A thorough understanding of the impact of knee OA on other muscle groups is required if optimal strengthening programs are to be developed and employed. Increasing research suggests that hip muscle weakness may be associated with knee OA, but little research has evaluated this to date.^[1]

The medial tibiofemoral compartment is the most common site of disease at the knee, presumably due to greater loads borne across this compartment relative to the lateral compartment, and research evaluating risk factors for medial knee OA progression has highlighted the potential importance of hip muscle strength.^[1]

In knee osteoarthritis (OA), the medial tibiofemoral compartment is the most common site of disease. The susceptibility of the medial compartment to OA development may relate to greater load distribution (i.e., 60–80%) to the medial than the lateral compartment, even in healthy knees, during gait. Excessive medial compartment loading is widely believed to contribute to medial OA progression.^[2]

At the knee, alignment (i.e., the hip knee-ankle angle) is a key determinant of load distribution. In theory, any shift from a neutral or collinear alignment of the hip, knee, and ankle affects load distribution at the knee. The load-bearing axis is represented by a line drawn from mid femoral head to mid ankle. In a varus knee, this line passes medial to the knee and a moment arm is created, which increases force across the medial compartment and hence contributing to the progression of medial Knee OA.^[2]

The hip is the only joint in the lower limb which allows much adduction and abduction and therefore any varus or valgus deformity of the leg can be compensated for only at the hip, and to a minimal extent at the subtalar joints. Any varus or valgus deformity between the hip and ankle must therefore influence hip mechanics. Varus deformity of the femur, knee, or tibia requires the hip to adopt an abducted position (valgus angulation) to maintain a straight mechanical axis of the limb in walking. The angle between the hip orientation line and the mechanical axis of a varus limb will exceed 90° and the 6° adducted position of the femur in normal walking is lost. This might affect the strength that can be generated by the abductor muscles although they are normal. Hence, it seems that the strength of Hip Abductor muscles is affected when the femur is placed in an abducted position due to Varus alignment. Depending on the amount of compensation, these patients might show a normal gait pattern, a delayed Trendelenburg’s sign or a Trendelenburg’s gait, due to the biomechanical insufficiency caused to the Hip abductors. ^[3]

Hence, our study aims at finding out the change in hip abductor muscles strength in Knee Osteoarthritis patients having Genu varum, and compares the findings to that of patients having knee osteoarthritis but no malalignment at Knee.

NEED OF THE STUDY - Due to change in the structural alignment of the knee joint in OA knee patients (as occurs in the Varum deformity), the femur is placed in an abducted position leading to the alteration in the length tension relationship of the Hip abductor muscles. Our study aims at evaluating the extent of weakness of the hip abductor muscles and whether any Gait alterations reduces the muscle activation over a due period of time. Also, the comparison of strength of the hip abductors in patients having varus knee with those having normal alignment may help us in better understanding of this mechanism.

ALTERNATE HYPOTHESIS: Hip Abductor muscle strength is reduced more in patients with Genu Varum, as compared to those with normal knee joint alignment; in the cases diagnosed with OA knees.

NULL HYPOTHESIS: There is no difference in the Hip Abductor muscle strength in patients with Genu Varum and those with normal knee joint alignment; in cases diagnosed with OA knees.

STUDY POPULATION 

Inclusion criteria: 

1) Diagnosed cases of OA Knees with Genu Varum Deformity.

 2) Diagnosed cases of OA Knees with Normal Knee Joint Alignment. 

3) Patients that belong to the Age group of 45-80 years. 

4) Both Genders (Males and Females)

Exclusion criteria: 

1) Patients having Genu Varum secondary to conditions other than OA Knees.

 2) Patients having Genu Varum deformity post fractures. 

 PROCEDURE 

 Subject meets Inclusion Criteria. Consents to participate 

 Subjects are divided into two groups – a)Patients having Genu Varum deformity (the Genu Varum deformity will be determined from an X ray of both knees, by an Orthopedic consultant) b)Patients having normal Knee joint alignment

 Assessments to be carried out by the therapist – 1) Hip Abductor muscle strength by hand-held dynamometer (on both the sides) 2) Quadriceps muscle strength by hand-held dynamometer (on both the sides) 3) Video analysis of patient’s gait (in coronal plane) for a) medio-lateral sway b) To check for the presence of Trendelenburg’s Gait.

 ïƒ˜ Analysis of the outcome measures 

 Statistics