In recent years, a number of chiropractic-related research studies have indicated that chiropractic care can improve various musculoskeletal conditions just as back and neck pain, and improve joint position sense. The latter is an interesting one: technically, joint position sense is an indicator of proprioception or an accurate sense of where our bodies are in space. Proprioception is important for coordination, falls prevention and even things like motion sickness. Recently, a study published in the Journal of Bodywork and Movement Therapies took a look at knee pain in patients with patellofemoral pain – or pain in and around the kneecap.
Patellofemoral pain (PFP) is a common disorder, thought to affect around 22% of the general population. It often affects physically active individuals, which is one reason it has gained the monikers “runners knee” and “jumpers knee.” In fact, young adults and particularly young women and those who participate in sports are common sufferers .
The condition is persistent and “usually leads to high levels of disability ” and can cause difficulty in performing everyday activities such as climbing the stairs or kneeling down. PFP is painful, obviously, and because of this pain, it can cause those affected to alter how they carry their weight to try and alleviate it. This, in turn, can alter posture and movement.
As chiropractors, we know that long term compensatory actions aren’t ideal, as they can lead to further complications such as additional strain on the “healthy” knee, increasing the risk of injury or damage.
The authors of this recent study referred to work which that found core strengthening exercises improved neuromotor control of the trunk had biochemical effects on the knee (Motealleh & Nejati 2019). The basis for this study, though, came from our own chiropractic research superstars, Dr Heidi Haavik and Dr Bernadette Murphy who demonstrated the effect of spinal manipulation on sensorimotor integration and proprioception back in 2012. The new research also drew on earlier work from the study’s lead author, Alireza Motealleh, back in 2016. This work looked at muscle activation in the quadriceps and gluteal muscle groups.
The 2020 study, a randomised controlled trial with 44 participants all of whom had patellofemoral knee pain, had some interesting ramifications for the nervous system as well as the knee.
In order to be part of this study, there were a number of criteria to be met in order to ensure the validity of the study. For example, patients couldn’t be on any anti-inflammatory medication or other treatments, had to have clinical evidence of PFP on one knee only, not pregnant or menstruating, or any disorders or diseases that affect musculoskeletal stuff or may prevent manipulation (MS, Ehlers-Danlos syndrome etc.). Any of these issues would alter the way the body experienced pain and inflammation.
The participants were then divided randomly into two groups: experimental and control. The experimental group received lumbopelvic manipulation (LPM) while the control group received a sham LPM that involved positioning but no thrust.
There were three main areas measured through this experiment:
- Joint position sense (JPS): in order to measure this, the knee was positioned by the experimenter and held there for 5 seconds, then the participant was asked to reposition their knee at that same angle. The difference between the desired angle and actual angle was measured. The participant was blindfolded, and this test targeted the participant’s proprioception of the joint, or accuracy of where the joint is in space by ‘feeling’. This test was repeated multiple times at 20 and 60 degrees of flexion.
- Balance performance: the participants stood on the impaired knee and stretched their leg toward the back left, back right, and forward. This is called the modified star excursion balance test. Each test was performed three times and the longest reach in each direction was used for analysis.
- Pain measurement: a visual analogue scale was used to rate pain (0 being no pain, 10 being maximum pain). The participant ranked their pain after completing three basic tasks (squatting and stepping up and down).
All of these measures were recorded for a baseline and recorded again after the intervention.
In news that will be exciting to nervous system enthusiasts (i.e. chiropractors), the study found a statistically significant reduction in knee joint position sense (proprioception) error immediately after the intervention. There was also a significant increase in balance performance, evidenced via excursion distance in the anterior direction following the intervention. There was no significant change in distances in the sham group in any direction. The study also found a statistically significant decrease in pain following intervention in the group that received lumbar-pelvic manipulation, and no significant reduction in pain in the control group.
As is the nature of science, there are limitations to the study. All of the measures were recorded by the same researcher who performed the intervention, which leaves this very much open to bias.
Also, it’s unclear how much the participants knew about lumbar-pelvic manipulation. Hence, if a participant was more informed they may have been able to tell which intervention they were receiving and bias the results.
Further research is required to assess how long the effect lasted, but given the way this research dovetails with what we already know about chiropractic care and proprioception, it is encouraging to read anyway! Make sure you read the full study, referenced below .
- Staff writer (2020), “Patellofemoral pain syndrome,” OrthoInfo, https://orthoinfo.aaos.org/en/diseases–conditions/patellofemoral-pain-syndrome/
- Motealleh. A., Barzegar. A., Abbasi. L., (2020), The immediate effect of lumbopelvic manipulation on knee pain, knee position sense
and balance in patients with patellofemoral pain: a randomized controlled trial, Journal of Bodywork & Movement Therapies, https://doi.org/10.1016/j.jbmt.2020.01.006