Does Your Kneecap Position Matter?

Recently we saw quite a few patients after they had knee replacement surgery in our clinics. Having treated many patients' knees over the years, I have seen lots of variations of how the kneecap (or patella) is positioned.  Some patients have kneecaps that are 'aligned' nicely, yet they regularly complain of knee pain. Others have kneecaps that seem to sit terribly yet they have no knee pain nor need a knee replacement. 

There is definitely still a lack of knowledge regarding the variability of patellofemoral (kneecap) alignment in both healthy and osteoarthritic knees. Yet, while training to be physiotherapists, we were taught about the importance of kneecap alignment. They said it should sit nicely in the middle of the knee, and the sulcus and patella tilt should be a certain "normal" angle.

When patients come into our clinics complaining of knee cap (patella) pain, it is not always due to knee cap alignment. Hochreiter and colleagues (2020, 2021) published 2 systematic reviews demonstrating that both healthy and osteoarthritic knees have highly variable patellofemoral (knee cap) alignment.

15 studies met the inclusion criteria for healthy knees while 8 studies were used for osteoarthritic knees.

The authors concluded that both healthy and osteoarthritic knees have extremely variable patellofemoral alignment. This may be due to variables when doing x-rays/ MRI scans, measuring techniques and the people studied. 

R Kneecap position

In order to treat patients with healthy knees with knee pain, a more precise knowledge of the complex relationship between the trochlea and patella (pictured above) is needed since the exact role of knee joint alignment in development of knee pain/ symptoms remains unclear. I have written previously that the hip, especially in females, and not so much knee alignment causes knee pain.

The authors also suggest that surgeons operating on osteoarthritic knees need to consider individual pre-operative patellofemoral alignment if they want to reduce anterior knee pain for patients after total knee replacement surgery. Note that running will not wear out your knees (or your joints). So what does? There is now evidence that osteoarthritis is not due to a mechanical aging process. Even if you already have osteoarthritis, exercise will not wear out your joints quicker.

So healthcare professionals should not be telling patients that their knee joint alignment is abnormal, especially since we do not even know what normal alignment is.

References

Hochreiter B, Hess S, Moser LB et al (2020). Healthy Knees Have A Highly Variable Patellofemoral Alignment: A Systematic Review. Knee Surg Sports Trau Arthrro. 28: 398-406. DOI: 10.1007/s00167-019-05587-z.

Hochreiter B, Moser LB, Hess S et al (2021). Osteoarthritic Knees Have A Highly Variable Patellofemoral Alignment: A Systematic Review. Knee Surg Sports Trau Arthrro. 29: 483-490. DOI: 10.1007/s00167-020-05928-3.