The following description of examination for a patient with suspected PFP will focus on aspects relevant to this condition and ignore much of the standard knee examination.
Subjective
Sometimes the subjective examination will provide the best clues as to the likely source of pain. As mentioned in the previous newsletter, PFP occurs with load-bearing activities on a flexed knee. The most common aggravating activities are ascending or descending stairs, squatting, jumping, and running. A subgroup of patients will report pain on prolonged sitting. For most patients the pain comes on early in the range of flexion, below 20 to 30 degrees.
A detailed ‘loading history’ is obtained during the subjective, with particular attention to recent changes in activity.
Objective
The patellofemoral joint specific tests include:
1. Squatting. Note where in range symptoms arise, and whether the patient alters their movement in response to pain or inability to fully load one/both sides.
2. Single leg squat. Again, note pain/range. Quality of movement is important. Do they lean to one side, drop or abnormally hitch the pelvis on the opposite side, twist in at the knee, or minimize knee bend?
3. Tracking. With the patient sitting, they actively extend the knee from 90 to 0 degrees. Note for a ‘J sign’ with the patella moving laterally close to extension. This test is more relevant for suspected patellofemoral laxity/instability than for PFP syndrome.
4. Palpation. Often, the joint is not tender at the time of examination, however the medial and lateral facets should be checked. Also check patellar lateral/medial glide for laxity or hypomobility. For differential diagnosis check the inferior pole (patellar tendinopathy), tibial tuberosity (Osgood-Schlatter’s or distal tendinopathy), the fat pad, ITB just superior to the knee (ITB ‘friction’ syndrome) and tibiofemoral joints/associated bone.
5. Strength testing. Relevant muscles to test using handheld dynamometry or functional tests include the quadriceps, gluteals (medius/minimus and maximus), and trunk side flexors.
6. Gait/running technique. This can be assessed on a treadmill or in the field.
Management
PFP can be very challenging to treat, and for many people with persistent/long term symptoms self-management will be ongoing. The following is an overview of recommended treatments based on research and anecdotal evidence.
1. Exercise. Quadriceps, and specifically VMO, strengthening has long been recommended for treating PFP. However, there is no good evidence that specifically targeting VMO is superior to improving overall quadriceps strength. What has been shown is that strengthening is superior when it targets both the hip and the knee musculature. This has been found to provide benefit in the short, medium, and long term. The challenge with knee strengthening is that many traditional quads exercises load the PFJ and exacerbate pain. Modifications are usually needed. Considerations include open versus closed chain exercises, knee angle under load, and isometric versus isotonic strengthening. Exercise should form the cornerstone of management, as deficits in both hip and knee muscle strength have been consistently demonstrated in people with PFP. Trunk muscle strengthening may also be beneficial, particularly in runners with PFP.
2. Patellofemoral taping. In isolation this intervention may provide short term benefit. In the medium term it has demonstrated benefit combined with other interventions including exercise. In practical terms many patients find taping to be effective for pain relief, and this assists with exercise compliance.
3. Foot orthoses. In selected patients orthoses have been shown to provide benefit, but only in the short term.
4. Manual therapy as a stand-alone treatment has no proven benefit.
5. Electrotherapy has not been shown to be beneficial.
6. No benefit has been found for certain other interventions including acupuncture/dry needling, blood flow restricted strengthening, or massage.
7. Gait retraining. There is conflicting evidence regarding the benefit of this intervention. It may be appropriate for a subgroup of runners with PFP.
Other considerations
1. Load management. In all patients with PFP, symptoms are influenced by the intensity and frequency of joint loading. It is often necessary to design a programme to account for this, with modifications as necessary to the targeted exercises they perform, and their day-to-day lifestyle loading patterns.
2. Education. PFP patients, particularly those with persistent pain, need to understand the nature of their condition, and when and how to modify their activities or seek additional treatment.
3. Pain management. Where pain is poorly controlled, and where a nociplastic pain state is suspected, behavioral and functional pain management strategies need to be considered.
References:
1. Collins, N et al (2013). Prognostic factors for patellofemoral pain: a multicentre observational analysis. British Journal of Sports Medicine, 47, 227-33.
2. Crossley, K et al (2016). 2016 patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions (exercise, taping, bracing, foot orthoses and combined interventions). British Journal of Sports Medicine, 50, 844-52.
Archived: Latest Trends in Management
Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal conditions. It accounts for 25-40% of all knee problems seen in sports medicine, and may have a prevalence of around 25% in the general adult population. It also remains one of the most challenging to manage. There is growing evidence that many young PFPS patients (up to 91%) experience persistent pain (21), and some may have a greater likelihood of developing early PFJ degenerative changes (14). You may be familiar with the ‘McConnell programme’, which was developed around 30 years ago, and is still popular today. Jenny felt VMO weakness contributed to patellar mal-tracking. She treated this with VMO strength programmes along with patellar taping techniques and other interventions (5). Below is a brief summary of the most up-to-date research on interventions for PFPS. Taping There is good research evidence that patellar taping helps symptoms in the short-term. However biomechanical studies have shown it does not do this by altering patellar tracking or improving VMO function. One theory is that taping works by compressing the patella into the groove, thus improving its area of contact, and reducing joint stress (11,20). VMO retraining While there is some evidence of VMO wasting in PFPS (8), and delayed onset of VMO contraction (15), research shows that quadriceps weakness is a generalized occurrence, affecting all four groups. It is still debated if this is cause or effect, as PFPS and knee swelling are potent inhibitors to quadriceps function. There is no evidence that specific VMO training is of any additional benefit to general quads training. While quadricepsstrength programmes have proven beneficial in improving symptoms (6), there is increasing evidence that hip / gluteal strength may be of equal or greater importance than quads strength for longer-term PFPS management (22). Hip strengthening There is evidence that females with PFPS have significantly increased femoral adduction compared to controls, when running or performing a single leg squat (18,22). Both males and females with PFPS had increased contralateral pelvic drop (18). There is also evidence of delayed gluteus medius onset and a shorter duration of contraction in PFPS subjects (1). Dynamic MRI studies have shown that in certain subjects with patellofemoral disorders, the patella does not track laterally. Rather, the femur internally rotates beneath the patella (10,12). There is also evidence that a group of subjects with PFPS have relative weakness of their hip external rotators and abductors (7). Rehab programmes specifically targeting hip rather than quads strengthening have demonstrated benefits in the short to medium term (7,21). Biomechanical interventions It is well recognized that individuals with faulty lower limb biomechanics are at greater risk of ACL rupture. And strategies such as the PEP programme have proven successful in part by targeting these Patellofemoral Pain Syndrome For information on all types of injuries visit: http://www.cssphysio.com.au/Doctors/fordoctors.html deficiencies. More recently there has been interest in the role of biomechanical interventions & neuromuscular retraining to reduce PFPS. Video biofeedback, mirror imaging & verbal cueing has been used successfully to assist runners with PFPS to reduce over-striding, pelvic drop and functional valgus, thus improving control and getting the knees wider during running (3,17,18,19). Pain control and central mechanisms As with any chronic pain state, there is mounting evidence of potential ‘central sensitisation’ mechanisms for maintaining pain states and dysfunction. Quads inhibition and inability to adequately load the knee are common long-term consequences of PFPS. There has been recent interest in disinhibitory interventions to help overcome this neural inhibition (4). Orthotics Studies have shown inconsistent results for the effectiveness of foot orthoses for treating PFPS. Some studies have shown good short-term results (16). There is most likely a sub-group of individuals who will benefit from this intervention (2,16). For more information on physiotherapy treatment of this condition, see: http://www.cssphysio.com.au/pdfs/0- Rehabilitation.pdf
References: 1. Barton, C et al (2012). Gluteal muscle activity and PFPS: a systematic review. BJSM, 47, 4. 207-214. 2. Barton, C et al (2011). Greater peak rearfoot eversion predicts foot orthosis efficacy in individuals with PFPS. BJSM, 45, 697-701. 3. Cheung, R & Davis, I (2011). Landing pattern modification to improve patellofemoral pain in runners. JOSPT, 41, 12, 914-919. 4. Harkey, M et al (2014). Disinhibitory interventions and voluntary quadriceos activation: a systematic review. Journal of Athletic Training, 49, 1, Epub. 5. McConnell, J (1996). Management of patellofemoral problems. Manual Therapy, 1, 60-66. 6. Natri, A et al (1998). Which factors predict long-term outcome in chronic patellofemoral pain syndrome. A 7-year prospective follow-up study. Medicine and Science in Sports and Exercise, 30, 11, 1572-1577. 7. Noehren, B (2012). Proximal and distal kinematics in female runners with patellofemoral pain. Clinical Biomechanics, 27, 4, 366-371. 8. Pattyn, E et al (2011). VMO atrophy: does it exist in PFPS? AJSM, 39, 7, 1450-145. 9. Peters J & Tyson, N (2013). Proximal exercises are effective in treating patellofemoral pain syndrome: a systematic review. International Journal of Sports Physical Therapy, 8, 5, 689-700 10. Powers, C (2003). The influence of altered lowerextremity kinematics on patellofemoral joint dysfunction. JOSPT, 33, 11, 639-646. 11. Powers, C et al (1997). The effects of patellar taping on stride characteristics and joint motion in subjects with patellofemoral pain. JOSPT, 26, 6, 286-291. 12. Souza R et al (2010). Femur rotation and patellofemoral joint kinematics: a weight-bearing magnetic resonance imaging analysis. JOSPT, 40, 5, 277-285. 13. Stathopulu E & Baildam, E (2003). Anterior knee pain: a long-term follow-up. Rheumatology, 42, 2, 380-382. 14. Thomas, M et al (2010). Anterior knee pain in young adults as a precursor to subsequent patellofemoral arthritis. BMC Musculoskeletal Disorders, 11, 9, 201 15. Van Tiggelen, D et al (2009) Delayed VMO to VL onset timing contributes to the development of patellofemoral pain in previously healthy men. AJSM, 37, 6, 1099-1105. 16. Vincenzino, B et al (2010). A clinical prediction rule for identifying patients with PFPwho are likely to benefit from foot orthoses. BJSM, 44, 12, 862-866. 17. Willey, R et al (2012). Mirror gait retraining for the treatment of patellofemoral pain in female runners. Clinical Biomechanics, 27, 10, 1045-1051. 18. Willey R et al (2012). Are mechanics different between male and female runners with patellofemoral pain. Medicine and Science in Sports and Exercise, 44, 11, 2165-2171. 19. Willson, J et al (2013) Effect of step length on patellofemoral joint stress in female runners with and without patellofemoral pain. Clinical Biomechanics, 29, 3, 243-247. 20. Wilson, T et al (2003). A multi-centre single-masked study of medial, neutral and lateral patellar taping in individuals with PFPS. JOSPT, 33, 8, 437-443. 21. Witvrouw, E et al (2013). Patellofemoral pain: consensus statement from the 3rd International Research Retreat. BJSM, 48, 3, 411-414. 22. Noehren, B et al (2013). Prospective evidence for a hip etiology in patellofemoral pain. Medicine and Science in Sport and Exercise, 45, 1120-1124.
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