RESEARCH FOR 2007 AT THE SPORTS INJURY CLINIC

We introduce to you our research into Patello-Femoral Pain Syndrome (PFPS) and VMO Cross Sectional Area(CSA) utilizing Real Time Ultrasound Imaging.

Our principal physiotherapist Michelle Blake is co supervisor alongside Professor Jenny Keating as a part of the Monash University Honours Program. We have collected 18 months of data at the Sports Injury Clinic in PFPS. In 2007 we are also researching the validity and reliability in utlilizing Real Time Ultrasound in measuring CSA in musculoskeletal imaging.

We are hoping to achieve both valid and reliable outcomes from our work that may assist in the recognition and management for patients suffering anterior knee pain, especially for General Practitioners.

From this research, we are also hoping to assist in establishing specific timelines to guide treatment efficacy, as well as establishing objective measures to both act a clinical feedback as well as delivering cost effective treatment for patients.

Ultimately we aim to develop recognized protocols that will assist in reducing patient physiotherapy visits through enhanced education strategies, as well as improving longitudinal outcomes and improving predictors for injection procedures or surgery.

Our data in 73 patients so far suggests:

1. A patient suffering anterior knee pain will have specific changes in VMO CSA. These changes range from as great as 45 % reduction in resting CSA of the VMO relative to the non painful knee.
2. If a patient is suffering anterior knee pain, the % increase in muscle CSA from resting to full isometric contraction will be decreased by 30- 85% relative to the non painful knee, suggesting pain inhibition can limit the activation of VMO
3. Within 4-6 weeks of receiving an average of 4.5 visits, clinically significant changes of both functional outcome measures and CSA can be achieved with a single exercise that amounts to 5 minutes a day. These improved functional outcomes correlated with a significant increase of both the resting VMO and contractile VMO cross sectional area (CSA)
4. Taping ( McConnell) is indicated in reducing anterior knee pain to improve VMO facilitation.
5. Injection therapy(C.S.I.)/ aspiration (if required)is indicated in improving immediate VMO function measured within 48 hours utilizing RTUS pre / pos measurements. ( this is to be studied further)
6. Surgical opinion ,injection therapy or further medical management may be appropriate after 8 weeks of management if 75% change in functional outcome measures have not been achieved.( this will be followed up over the next 12/12)
7. the rate of return for our preliminary anterior knee pain group measured 2.2 visits over an 18 month period.

If you would like further information on our clinical trial for anterior knee pain please contact michelle blake at michelle@tsic.com.au

We anticipate our data will be finalized by mid 2008 and hope to include rotator cuff pathology in our further study.

ANTERIOR KNEE PAIN AND THE GP

One of the major causes of patellofemoral pain syndrome (PFPS) referred to in the literature is the influence of vastus medialis obliquus muscle(VMO) and its contribution to anterior knee pain. References are made to decreased muscle bulk and poor facilitation.We know through both cadaver and surgical findings, there remains anatomical division of the VMO due to the difference in muscle fibre insertions. The vectors created by the insertional angle of VMO may relate to effecting patella positioning upon contraction of either a superior glide ,or a more medial force vector. Although the early literature suggested that an imbalance of vastus medialis and vastus lateralis(VL) may relate specifically to anterior knee pain, recent studies have not supported this specifically.

Research so far suggests that firing patterns of the VMO may not specifically be responsible for PFPS as in asymptomatic patients there was not an alteration in the firing pattern of VMO preceding VL. Because of this lack of change in the firing pattern, some of the investigators have concluded that general quadriceps strengthening only is required in the rehabilitation of patellofemoral pain. It has been found that taping the patella of patellofemoral pain sufferers causes an earlier activation of the vastus medialis obliquus and a delayed activation of the vastus lateralis particularly on step descent. It could be assumed that the VMO in the patellofemoral pain sufferers needs to fire earlier to overcome the abnormal tracking forces or biomechanical forces as distinct from the non painful knee

Other predisposing factors exist in PFPS such as training errors, biomechanics of feet and pelvic dynamic posture as well as the co- existence of degenerative changes within the knee.This should not be dismissed as OA pain if there is the presence of anterior knee pain- the two can co-exist and pain and function can still be improved in this population group.(crossley et.al). It is found that PFPS can co exist in the OA knee and pain can be reduced with McConnell taping in these knees.

Assessment of the Patello Femoral Joint

Assessing passive movement of the patella in all directions (medial, lateral, superior, inferior) is imperative as is the para patella surrounding tissue. Assessing the position of the patella in relation to the femur for tilt, rotation and glide may guide you with deciding to tape to correct these mechanical positions. The tests for patellar position may not be reliable and are difficult to validate especially dynamically. Skyline views can be useful for assessing lateral tilt or displacement. These can be requested at 30,60 and 90 deg. knee flexion. You can also assess the depth of the trochlea groove and femoral condyle architecture.

Patella apprehension can also be useful at determining if the pain is ‘their’ reported knee pain as distinct form a ‘different’ pain. Compress the patella gently into the trochlea groove and ask the patient to ‘ gently’ contract their quads- SLOWLY! This test can be very provocative and is a test surgeons use.

Muscle activation of vmo

The clinician must assess the state of the vastus medialis obliquus. In most cases, there may be definitive muscle wasting as demonstrated in our findings to date utlilizing Real Time Ultrasound VMO measurements.(RTUS). This may be bilateral in some knees. On occasions, the vastus medialis obliquus may be strong and bulky but rendered ineffective due to its poor firing /timing of activation in a loaded position ,hence it is important to assess the VMO contraction in weightbearing. Often a patient is able to contract the vastus medialis obliquus correctly while sitting but not while standing.

Examination of the hip is also an important component of the clinical assessment of patellofemoral pain. Internally rotated femurs cause tightness of anterior hip structures especially femoral anteversion . This can often lead to the appearance of a patella squint with the patella anatomically facing medially in stance. Restricted hip range of motion, decreased gluteal firing as well as strength can also influence femoral positioning in weghtbearing.A concerted rehabilitation program of pelvic balance and strengthening should be considered in these cases as they often do poorly with surgery alone if there is pelvic mechanics involed. Any weakness or incoordination requires physiotherapy treatment

Patella taping

The aim of patella taping is to see if we can alter the pain associated with PFPS. The patella should sit equally between the two condyles. You will determine its position from your assessment Lateral displacement of the patella is a common finding which is described as having restricted medial glide. The medial and the lateral patellar borders should be of equal height. A common abnormality is a lower lateral border, a reflection of tight lateral retinacular fibers. This is called a lateral tilt. The long axis of the patella should be parallel with the long axis of the femur and deviation is described as a rotational abnormality. Check the insertional angle from the inferior pole of the patella to the tibial tuberosity attachment. The superior and inferior poles of the patella should lie in the same plane. The abnormality seen most commonly in this axis is called posterior tilt and clinically results in the inferior pole being difficult to palpate as it is embedded in the infrapatellar fat pad.

foot biomechanics

Both WB and NWB foot posture should be assessed looking for pronation, foot alignment ( especially foot ER or rotation during gait)

Functional balance and alignment with squat should also be assess for pain and increased valgus/varus at the knee

A Podiatry opinion is recommended in these cases

Treatment

The management of a patient with patellofemoral syndrome requires an integrated approach which may involve:

• reduction of pain and inflammation
• taping to correct abnormal patellar position
• vastus medialis obliquus strengthening
• stretching
• massage therapy
• bracing
• correction of abnormal biomechanics of foot and pelvis
• correction of other possible causative factors
• surgery

Reduction of pain and inflammation

The first priority of treatment is to reduce any acute inflammation that may be present. This is achieved with a combination of rest from aggravating activities, ice, NSAIDs .Some electrotherapy agents can be used to assist in this stage. Taping can be applied in the inflammatory stage and should reduce the pain by 50% + if effective

Taping

The aim of taping in the management of patellofemoral pain is to change the reported anterior knee pain with functional tasks as well as on VMO contraction. Taping the patella relieves pain but the mechanism of the effect is still being investigated. Jill Cook and Jenny McConnell recommend taping the patella of symptomatic individuals that decreased pain by 50%. Patellar taping has been associated with increases in loading response knee flexion, as well as increases in quadriceps muscle torque. Taping is an effective interim measure to relieve patellofemoral pain while other biomechanical abnormalities (e.g. vastus medialis obliquus weakness, excessive pronation) are being corrected.

Following from taping, the knee should be immediately functionally assessed for the prior pain provoking activity.ie squat, steps. Tape can be left on for 24 hours especially in the chronic and constantly painful knee.

Taping should utilize hypoallergenic tape ( fixomul/ hyperfix) and a covering rigid tape for greater force. A barrier for the skin can also be used such as comfeel.

Muscle training

Muscle retraining should also have associated objective measures to assess the effectiveness of the strength program. Pelvic control may need to be addressed as poor anterior, lateral or rotational control of the pelvis during activity may load the patellofemoral joint excessively. Functional core stability exercises should be considered including closed kinetic chain exercises.

Other considerations should be made in dealing with anterior knee pain such as:

1. Massage
2. Stretching
3. Orthotics(Excessive rear foot mal alignment causes tibial rotation in the lower limb and this changes the alignment of the patella in the femoral groove. Orthotics may be required to correct this.)
4. Correction of other precipitating factors( training error, running biomechanics, functional strength)
5. Injection Therapy
6. Surgery

Surgical opinion is certainly a valid option if conservative treatment fails to meet improved functional outcomes. Lateral release and realignment surgery can be considered as an option if considerable biomechanical factors are dominating as well as addressing surrounding soft tissue that may be provocative for pain.

We will be bringing you a follow up article on injection and surgical opinion for PFPS in upcoming Newsletters.

Conclusion:

There is sufficient evidence to suggest that PFPS can be managed conservatively.

It is recommended that a time line of management should be recommended for your clients of 8-12 weeks and management may encompass a combination of taping, VMO/Quadricep strengthening, biomechanical assessment and correction if required.