Friday, July 2, 2010

Anterior Knee Pain & It's primary treatment

I. Introduction
o other causes of anterior knee pain, besides primary PF pain
o differential diagnosis may be more difficult than anticipated owing to interrelationships
o realize that more than one problem may exist concurrently
o a small acute injury may stir up an underlying mechanical anomaly that had previously been painfree; daily activity with a malalignment may be enough to perpetuate symptoms

II. Plica
o embryologically the knee is formed by the fusion of three synovial compartments and the intervening synovial tissues resorbed. The plicae are synovial remnants of these synovial tissues
o intrapatellar plica (ligamentus mucosum) most common and runs parallel to the ACL; it has no clincial significance
o suprapatellar second most common: acts as a tethering band in the superior portion of the quadriceps bursa and may separate it into two separate segments
o medial plica least common, but probably produces the most symptoms; runs distally along the medial aspect of the knee from the level of the superior pole of the patella to insert into the medial fat pad
o incidence of medial plica ranges from 9.1-50%
o as knee is passively flexed form 30-60°, this plica can be seen to slide over the MFC beneath the patella; ER of tibia causes wedging of the plica between the medial facet and the MFC
o generally tender one fingerbreadth proximal to the distal pole of the patella, medially
o symptoms increased with repetitive activities

o painfree stretching
o LE strengthening, avoiding repetitive activities
o work in painfree range
o occasional injection and/or surgical resection

III. Prepatellar bursitis
o common in wrestlers
o cause: either acute trauma from a single blow or chronic irritation
o if acute, often the result of small blood vessel rupture, resulting in aspiration of blood
o if chronic, likely the result of chronic inflammation, and aspiration will not contain blood
o in wrestlers, probably a combination of chronic and acute onset
o chronic bursitis much more difficult to treat; has a high recurrance rate; surgery reveals a thickened bursal wall
o high incidence of septic bursitis (>95% in Myshnyk's series); staphylococcus aureus most common cause
o repeated aspiration of chronic bursitis discouraaed owing to the high rate of infected bursae
o swelling is superficial to patella
o blood workup not particularly helpful in making diagnosis of septic bursitis

o cortisone injection not helpful in most cases
o aspiration (limited)
o consider HVPC
o maintain CV, ROM
o maintain quad strength without increasing swelling
o consider pool therapy
o kneepad when returning to kneeling activity

IV. Iliotibial band friction syndrome
o commonly seen in runners, bikers
o symptoms can be seen at hip, knee or both
o hip pain generally over the greater trochanter, and involves both the TFL and gluts
o knee pain is over LFC
o at 0°, ITB is anterior to LFC; as the knee passes 30° of flexion, it passes across the LFC to become posterior
o diagnosis is made on history, palpation and special test at knee
o must assess alignment and treat underlying cause; varus or valgus knee alignment, and pronation can predispose to symptoms at knee
o tight ITB (+ Ober test) and tight hamstrings are diagnostic and form basis for treatment program
o assess patella for related problems

o ice
o activity modification
o treat malalignment
o flexibility
o strength, posture, predisposing habits (running surface)
o surgery used for chronic cases unresponsive to conservative management; consist of making a "window" in ITB in area of irritation

V. Fat pad impingement
o rare problem, generally not painful
o may be related to patellar malalignment (AP tilt)
o correct underlying cause
o tender medial and/or lateral to patellar tendon on fat pad
o quad setting (screw home mechanism) hurts
o thickening of fat pad produces additional irritation as problem progesses
o can be chronic or acute

o correction of underlying cause
o ice
o HVPC, ionto/phonophoresis
o cortisone injection (NOT into the tendon)
o surgical resection

VI. Osgood-Schlatter's disease
o originally described by Osgood & Schlatter in 1903
o tibial tuberosity apophysitis - result of tensile forces
o self-limiting problem with pain & enlargement of the tibial tuberosity
o incidence for those in sports = 21%, those uninvolved = 4.5% for an overall incidence of 12.9%
o Males:females = 1.5:1 to 4:1 (depending upon who you ask)
o common in athletes with a past history of Sever's disease
o average age of onset = 13.1
o bilateral in 56%
o etiology is likely the result of avulsion of a portion of the developing ossification center and overlying hyaline cartilage
o inflammatory changes occur seconday to micro-avulsion fractures of the tuberosity
o S&S: dull ache increased with running and jumping; local redness and point tenderness
o x-ray may demonstrate soft tissue swelling anterior to tibial tuberosity

o symptomatic
o ice
o stretching, strengthening
o activity modification
o rarely immobilize

Complication: tibial tuberosity fracture; rare, requires surgical fixation

VII. Sinding-Larsen-Johansson disease
o similar to Osgood-Schlatter, but symptoms present at the inferior pole of the patella
o age 10-13
o no history of trauma
o hypothesize that etiology is avulsion of the periosteum at inferior pole of the patella with resultant ossification
o seen with repetitive traction at the patellar tendon attachment site
o knee pain exacerbated by running, stairs and kneeling
o may have concomitant Osgood-Schlatter
o tender over inferior pole
o x-rays demonstrate irregular calcification at inferior pole

o similar to Osgood-Schlatter

VIII. Patellar tendinitis
o Blazina referred to patellar tendinitis and quadriceps tendinitis as "jumper's knee" in a classic 1973 article; this same paper described the "Blazina scale" of pain and functional impairment
o focus here on patellar tendinitis as quadriceps tendinitis is rare (usually over age 40)
o very difficult problem to treat; patients often wait until problem is advanced before seeking treatment
o specific point tenderness at distal pole of patella (must tip patella to get at distal pole)

Blazina's phases:
Phase I: Pain after activity only. No undue functional impairment.
Phase II: Pain during and after activity. Still able to perform at a satisfactory level.
Phase III: Pain during and after activity and more prolonged. Patient has progressively increasing difficulty in perfoming at a satisfactory level.

Stages of healing:
o cell mobilization
o ground substance proliferation
o collagen protein synthesis
o final organization

o controlled activity
o modalities
o medications
o exercise

Principles of eccentric exercise program:
o muscle length
o intensity
speed of contraction

Optimal loading:
o must try to mimick demands of their activity

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