Undiagnosed knee injury (I suspect meniscal damage!), please help!

Up until September 2014 I was a regular jogger (3-4 times per week), before I began to experience an ache on the inside of my left knee, 15-20 minutes into a run. After a few weeks of 'testing' the knee on less frequent and softer runs, the pain got worse, to the point where i felt the same pain when walking or at rest. Four months on and I have entirely cut-out running from my day to day activities, and keep any walks to a slow pace, as any moderate exercise brings back symptoms. 

I would describe the pain as a dull ache, which feels as if the knee is not fully supported/stable. When walking I can feel that my form is affected by the instability of the knee. When at rest, extending the effected leg out infront relieves the feeling of instability. After exercise the knee tends to 'lock' ever-so-slightly (this is not a painful sensation), to which a kicking motion 'unlocks' the knee. If I was to locate the pain on a diagram of the knee, it falls around the medial miniscus region.  

When comparing the two knees, there is no visual clue as to what is wrong with the knee, which is why a number of doctors have told me that my knee is fine. To touch, the left knee feels slightly more 'boney' along the inside than the right one. I have tried a number of knee exercises (squats, extensions, thigh contractions) and hip strenghening exercises, as commonly prescribed for runner's knee injuries, but none of these have helped in the rehabilitation. 

Its been four months now, and although I know this is a first world problem and I am still lucky to have my limbs, it is having a negative impact on my livlihood!

Has anyone experienced anything similar? I'd really appreciate your comments/advice!

Did you have an MRI done, Harry? When I had a torn meniscal it was an abrupt sharp pain. The actions were the same though. Wearing a knee brace helped in keeping the knee stable. However, when the cartlidge was wearing the lockng and tend to fall backward were the symptoms with the dull throbbing pain. Good luck. 

You really need to see a doctor and have the proper tests to see what is wrong with your knee. As you say, it could easily be meniscal damage . . About ten years ago I had that problem.  At first the pain was intermittent, and then more or less whenever I walked, and finally actually painful with the leg at rest.  i had an arthroscopy which cleaned up the damaged catilage and also smoothed the top of the bone, and I had another ten years of perfect knee function.  finally, I have needed a total knee replacement, but then I'm 70 and the poor old knee has taken a lot of weight for a lot of years.!  You need an expert to tell you what the problem is . .hope you get it sorted.  You may or may not be doing it good by knee exercises, so better to get an expert opinion . . .

1st line of defense, xrays for bone damage and MRI for soft tissue ordered by an orthopedic surgeon. Sounds like possible meniscus tear or strain but whatever it is you aren't going to get better till you get proper professional help. Until a diagnosis and treaent, you could be making it worse and the healing process longer