Goniometric alignment of the normal knee joint and the factors which affect it.

Objectives: Establishing a normative database for anterior plane knee joint alignment in a population is helpful in assessing patients with disorders of the knee joint specially osteoarthritis. Therefore we aimed at establishing the normal alignment in the Sri Lankan adult population using the goniometer which is an inexpensive and simple method of measurement.

Methods: A total of 420 healthy adult volunteers (210 men and 210 women) above 25 years of age were recruited and the anterior plane knee alignment was measured using a hand held metal goniometer.

Results: The mean knee joint alignment was 180.56° (SD 2.39) and 183.04° (SD 2.34) in males. The knee joints of the females were varus-oriented by, 2.48° than those of males (p< 0.0001). In the females the knee joint alignment showed a gradually varus inclination with increasing age (p< 0.05). Lifting heavy weights in males caused a significant varus inclination of the knee joint while BMI and squatting for long periods did not have an effect on the normal alignment.

Conclusions: Female knees are more varus inclined than that of males in the Sri Lankan participants and this inclination increases with age. Reasons for this could be genetic and lifestyle differences and may partly explain the reason for the predominance of varus osteoarthritis in Sri Lankan females.