Is this leads to numbness of the leg?

There is differant pathophysiology mechanisms for leg numbness but this is not one Magda :)

YES: numbness is usually a sign of higher level neuronal pathology

Not what is described here though. In essence true numbness will come from pathology from 1st 2nd or 3rd order neurons within spinothalamic or dorsal column tracts

I prob should explain that poor somatosensory input described above is not suggesting full lession eg transaction but a functional lession with decrease action potentials in neurons named above resulting aberrant information and therefore aberrant function

In OA knee,,,there may be anserine bursitis==>compression of saphenous nerve==>saphenous neuralgia(may be numbness of medial side of leg)

mechanism of joint stiffness

-----Stiffness: of short duration, also termed gelling . It’s explained by increase in synovial fluid viscosity due to accumulation of hyaluronic acid in and around the thickened capsule and synovium ( Creamer P, Hunt M and Dieppe P (1996): Pain mechanisms in osteoarthritis of the knee. Effects of intra-articular anesthetic. J. of Rheumatol. 23;109:118. )))))))

The ability to utilize muscle strategies that resist external forces

is especially important in a population where joint stability is reduced

during dynamic activities. Persons with knee OA report reduced

joint stability during activities of daily living, and this

instability interferes with their ability to function (Fitzgerald

et al., 2004). Increased passive laxity in the medial direction has

also been repeatedly found in persons with knee OA (Schmitt

and Rudolph, 2007; Rudolph et al., 2007; Lewek et al., 2004). To

overcome instability and joint laxity, persons with knee OA may

utilize higher antagonistic muscle activity and develop higher dynamic

joint stiffness during walking. However, joint stiffness in

the OA population has not been explored.

Factors underlying increases in dynamic joint stiffness, such as

higher antagonistic muscle activity, may overcome dynamic instability

but potentially expedite the progression of cartilage deterioration

through higher sustained joint compression forces (Piscoya

et al., 2005; Griffin and Guilak, 2005).

Proprioception can be defined as the conscious or

unconscious perception of extremity position in space

and the awareness of movement and position of the

joints [16,24]. This sense plays an important role in the

organization of periarticular muscle activities, which

provide stability of the joints [11–13]. The sense of

proprioception is known to decrease with age [21,25].

However, when patients with knee OA are compared

to healthy individuals at the same age, there is much

more loss of the sense of proprioception [9,18,23]. A

correlation has been described between the progression

of OA and impairment in proprioception [11,12]. Theoretically,

it is not quite known whether osteoarthritis

is the cause of loss in proprioception, or the impairment

of proprioception results in osteoarthritis.

Various studies have been conducted regarding the

effects of intra-articularHAtreatment on pain and functional

condition in patients with kneeOA[4,15],whereas

there is only one study investigating the effect of HA

injection on proprioception [20]. The purpose of this

study is to determine the short-term effects of intraarticular

injection of HA on proprioception, isokinetic

muscle force, self reported pain and functional condition

in patients with kneeOA. The hypothesis primarily

intended to be tested is as follows: “One of the mode

of actions of intra-articular hyaluronan in knee OA is

the increase of proprioception.” Diracoglu D, Vural M, Baskent A, Dikici F, et al. (2009): The effect of viscosupplementation on neuromuscular control of the knee in patients with osteoarthritis. Journal of Back and Musculoskeletal Rehabilitation 22:1–9.

The assertion that reduced proprioception leads to OA development and/or progress is a compelling one that has lead to many studies investigating "proprioception" in various patient populations. Proprioceptive deficits are commonly measured under carefully controlled conditions in which the subjects is positioned seated in a device that keeps the thigh immobile and the lower limb is attached by a cuff around the ankle that can move thereby creating knee motion. The lower limb is often encased in an inflatable sleeve to distribute pressure produced by the cuff, and subjects wear headphones and blindfolds to prevent auditory and visual input. The subject is then asked to reproduce a joint position or indicate when joint motion has occurred and errors in repositioning and thresholds to detect motion are recorded.

While deficits may be identified under these condition, there is some question about how they relate to functional movements that occur under very different conditions? During weightbearing activities sensory input to the nervous system would be much greater and much more varied. In addition, Hurkmans et al (2007) demonstrated that the minimal detectable difference in proprioception in people with knee OA was over 6 degrees. This may explain why some studies have shown statistical differences in proprioception while others have not and may indicate that differences less than 6 degrees may not be clinically meaningful. The following papers providing a good perspective on this topic.

Knoop, J., Steultjens, M.P.M.,van der Leeden, M.,van der Esch, M.,Thorstensson, C.A.,Roorda, L.D.,Lems, W.F.,Dekker, J. Proprioception in knee osteoarthritis: A narrative review Osteoarthritis and Cartilage Volume 19, Issue 4, April 2011, Pages 381-388

Knoop, J. , Van Der Leeden, M. , Van Der Esch, M. Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: Results from the Amsterdam Osteoarthritis Cohort. Arthritis Care and Research 2012; Arthritis Care and Research 64 (1) , pp. 38-45

Hurkmans, E.J.,Van Der Esch, M.,Ostelo, R.W.J.G.,Knol, D.,Dekker, J.,Steultjens, M.P.M. Reproducibility of the measurement of knee joint proprioception in patients with osteoarthritis of the knee. Arthritis Care and Research Volume 57, Issue 8, 5 December 2007, Pages 1398-1403

Thanks alot