The Knee Joint

Introduction & Epidemiology

Knee injuries are amongst the most common injuries next to shoulder, low-back, and neck pain seen in general practice (Picavet et al. 2003). They can be divided into two logical subgroups: traumatic and atraumatic knee injuries.

Traumatic injuries commonly involve a specific mechanism of injury such as during sports and they usually have a rapid onset. Atraumatic injuries on the other hand are rather overuse injuries that build up gradually over time with an insidious onset.

In primary care, the reported incidence is 13.7/1000 and the prevalence is 19/1000 persons per year for knee injuries (van der Linden et al. 2004)

Course 

The course of knee complaints appears not to be too favorable. Reports show that at a 12-month follow-up, 33% of patients with atraumatic knee pain and 25% of patients with traumatic knee pain report full recovery (Wagemakers et al. 2012).

Prognostic factors

For atraumatic knee injuries, the following prognostic factors were associated with persistent knee symptoms after 1 year (Belo et al. 2009):

• age >60 years
• low educational level
• kinesiophobia
• comorbidity of the skeletal system

For traumatic knee injuries, however, Wagemakers et al. (2012) report the following prognostic factors:

• age >40
• female gender
• pain score >5
• popping sensation during trauma

Multivariate logistic regression analysis revealed that only age >40 was a prognostic factor for persistent complaints at the 1-year follow-up.

Basic Assessment

Depending on the outcome, your basic assessment can give you the following info:1)  Limitations in range of motion and their end-feel can guide in structural assessment (e.g. bone to bone=osteoarthritis, empty=tendinopathy due to pain)

It’s best to start with Active Range of Motion Assessment:

Standard values for the range of motion in different directions are as follows: 

Flexion: 0-135°

Extension: 0-15°

AROM assessment is then typically followed by Passive Range of Motion Assessment (PROM) which you can watch with a click on the following video:

During PROM assessment, it’s important to compare the range of motion as well as the end-feel of the affected knee with the unaffected side.

References

Artus, Majid et al. “Generic Prognostic Factors for Musculoskeletal Pain in Primary Care: A Systematic Review.” BMJ Open 7.1 (2017): e012901. PMC. Web. 6 Sept. 2018.

Belo, J. N., et al. “Prognostic factors in adults with knee pain in general practice.” Arthritis Care & Research 61.2 (2009): 143-151.

Collins NJ, Bierma-Zeinstra SM, Crossley KM, van Linschoten RL, Vicenzino B & van Middelkoop M. (2013) Prognostic factors for patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2013 Mar;47(4):227–33.

Kastelein M, Luijsterburg PA, Wagemakers HP, Bansraj SC, Berger MY, Koes BW, Bierma-Zeinstra SM. Diagnostic value of history taking and physical examination to assess effusion of the knee in traumatic knee patients in general practice. Archives of physical medicine and rehabilitation. 2009 Jan 1;90(1):82-6.

Picavet, H. S. J., and J. S. A. G. Schouten. “Musculoskeletal pain in the Netherlands: prevalences, consequences and risk groups, the DMC3-study.” Pain 102.1-2 (2003): 167-178.

Van der Linden M, Westert G, Bakker D & Schellevis F. (2004) Tweede Nationale Studie naar ziekten en verrichtingen in de huisartspraktijk. Klachten en aandoeningen in de bevolking en in de huisartspraktijk. Utrecht/Bilthoven: NIVEL/RIVM. 2004

Wagemakers HPA, Luijsterburg PAJ, Heintjes EM, Berger MY, Verhaar JAN, Koes BW & Bierma-Zein- stra SMA. (2012) Predictors of persistent complaints after knee injury in primary care. Br J Gen Pract. 2012 Aug;62(601):e561–6.