Let me set this one up for you. I was a clinical student at an outpatient physical therapy clinic. I had graduated with my undergraduate degree about 2 weeks prior, I had been at work since 6:30 AM, and I had been battling a vicious cold for who knows how long, and it was now about 7:00 PM, and I was engaged in a VERY healthy discussion regarding knee pain with a patient. There was a lot of talking points made about how his knee hurt with descending stairs and jumping, how his single leg stance was particularly bad, and how his single leg bridge, squat, and eccentric quad control with stairs were astronomically impaired. However, this gentleman refused to believe my convictions that his glutes we weak, even after going old school and doing a prone glute manual muscle test with him.
Although the main point of our talk was that just because VMO strengthening was prescribed by his MD, it doesn’t mean that it is his main or only dysfunction, or that he doesn’t need anything else in his treatment plan. My main take away was that his prescription said patella-femoral osteoarthritis. Huh, I thought. Odd to see osteoarthitis on a prescription for someone in their early twenties. Usually it’s Chondromalacia Patellae. I realized that I didn’t even really know the true difference. I wondered if this guy knew the difference either. Is there a difference, and does it change the approach to treatment?
It was once thought that Chondromalacia was a precursor to patella-femoral osteoarthritis (1) but has been refuted since (2)(3). There are apparently underlying differences in the “softening” of the cartilage in chondromalacia, and the progressive wearing away of the cartilage in osteoarthritis, with the softening of the cartilage not always resulting in wearing away (3). Osteoarthritis is commonly associated with a decrease in joint space, which typically results in gradual wearing away of remaining cartilage or underlying bone (5).
Another difference between these two is the average age of incidence between the groups. Chondromalacia typically occurs in younger individuals (think teens and 20′s) while osteoarthritis occurs typically within older populations (50-60+). Besides the age differences between the two conditions, there are also varying risk factors for the two.
- Joint laxity
- Change in activity level
- Significant growth spurts
- lower extremity muscle weakness
- Increased BMI
- Over activity
- Previous knee surgery
- Joint laxity
The treatment of the two will look very similar for these two conditions. Pain reduction will typically be the main initial focus with my patients with CP and OA. This will be accompanied with accessory muscle strengthening such as the glutes, trunk, and hip flexors if weak as well as lower extremity stretching, single leg balance work, and joint mobility work. Once pain reduction has occurred, I will then address the strength of the primary muscles surrounding the knee such as the VMO, other quads, hamstrings, and gatroc, and incorporating this strengthening into overall movement patterning (ie. squat/lunge) and functional training ( ie. stairs). Depending on the patients’ ages and activity levels, I will progress to more dynamic drills such as plyometrics if needed.
The major difference in these conditions regarding progression is that OA is a progressive condition that MAY (I’m not saying it always will) end up with injections, resurfacing, or eventual replacement of joints, while CP typically subsides with proper activity management, and strengthening.
I hope I have been able to clarify some differences between these two commonly interchanged conditions that are different in multiple ways. I learned a simple lesson back then, and was better able to educate this patient regarding why I had developed the treatment plan I did, and he was able to reduce his pain significantly within two months and return to previous activities without problem.
3. http://books.google.com/books?id=YfFj8Gbq5H0C&pg=PA53&lpg=PA53&dq=chondromalacia+and+osteoarthritis&source=bl&ots=6xjX6fJAvH&sig=fiC3Bmj3QMbYzKIwgaDEk8xy0jY&hl=en&sa=X&ei=ZO09Ub6vFdCuyAGzwYDADQ&ved=0CI0BEOgBMAg#v=onepage&q=chondromalacia%20and%20osteoarthritis&f=fals. Pages 53-54.