Chapter 6 The Knee continued. Pathologies and Related Special Tests Trauma may result from: –...
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Transcript of Chapter 6 The Knee continued. Pathologies and Related Special Tests Trauma may result from: –...
Chapter 6
The Knee continued
Pathologies and Related Special Tests
Trauma may result from:– Contact-related mechanism– Rotational forces– Overuse– Degenerative changes
Uniplanar knee sprains
Instability in only one plane Isolated to a single structure MCL/LCL = valgus/varus instability in frontal
plane ACL/PCL = anterior/posterior shift in sagittal
plane
Medial Collateral Ligament Sprains
Damaged from:– valgus tensile forces; blow to lateral aspect– Noncontact valgus loading– Rotational force
Force dissipated through:– Full extension – superficial and deep layers of
MCL, anteromedial and posteromedial joint capsule, tendons of pes anserine
– Flexed beyond 20o – superficial layer of MCL
MCL Sprains
Involvement of other structures– Medial joint capsule and medial meniscus– ACL– Distal femoral physis– Patella
Evaluative Findings– Table 6-4, page 218
MCL Sprains
Nonoperative Treatment– Adequate blood supply– Functional rehabilitation
Protection, controlled ROM, strengthening, proprioception training
– Knee braces
Operative Treatment– High complication rate
Lateral Collateral Ligament Sprains
Damaged from:– Blow to medial aspect of knee– Internal rotation of tibia on femur
“springy” end-feel Involvement of other structures
– Lateral capsule– ACL– Peroneal nerve
LCL Sprains
Poor healing properties and its’ importance in providing rotational stability to the knee often necessitates surgical repair
Evaluative Findings– Table 6-5, page 219
Anterior Cruciate Ligament Sprains
Damaged from:– Force causing anterior displacement of tibia on
femur (or femur driven posteriorly)– Noncontact-related rotational forces– Hyperextension of knee– Unlike other ligaments, most arise from
noncontact torsional forces
ACL Sprains
Isolated trauma unlikely Involvement of other structures:
– Other ligaments– Menisci– Anteromedial or anterolateral joint capsule– Per anserine, biceps femoris, IT band
ACL Sprains
Predisposing factors– Intrinsic vs. extrinsic– Table 6-6, page 220
Signs and symptoms– Hearing and/or sensing a “pop”– Loss of function/limited ROM– Swelling (geniculate artery)
Intracapsular/extravasate
– Lachman’s test/anterior drawer test
ACL Sprains
Evaluative Findings– Table 6-7, page 221
Test PCL top rule out “false-positive” “partially torn ACL”
– Partial trauma leads to dysfunction, instability, increased stress on remaining fibers
– Predisposed to future injury
ACL-deficient knee– Susceptible to degenerative arthritis
ACL Sprains
Rehabilitation focuses on restoring ROM, lower extremity strength, proprioception– Knee braces
ACL reconstruction– To perform activities involving cutting and pivoting– Donor tissue options
Autografts vs. allografts
– Accelerated rehabilitation programs
ACL Injuries in Females
Experience a disproportionately high rate of noncontact ACL injuries relative to males
Predisposing factors (Table 6-6)– Narrower intercondyler notch widths
Phases of the menstrual cycle– Surging levels of estrogen and progesterone =
increased laxity– Risk increased 1 week before and 1 week after
start of cycle, when ACL is most lax
Posterior Cruciate Ligament Sprains
Damaged from:– Tibia being driven posteriorly on femur– Hyperflexion/hyperextension– Landing on anterior tibia while knee is flexed
Figure 6-23, page 222
Signs/symptoms– May be asymptomatic at first– s/s similar to strain of medial head os gastroc or
posterior capsule
PCL Sprains
Signs and symptoms– Pain in posterior knee– Weakness of hamstrings and quadriceps– Reduced ROM during flexion– Posterior drawer and sag tests– Increased instability when other posterior
structures are also damaged Evaluative Findings
– Table 6-8, page 222
PCL Sprains
Predisposing factors– Joint loading– Joint congruency– Muscular activity
Posterior laxity does not always result in knee dysfunction
Nonoperative treatment– May lead to chronic instability over time
Rotational Knee Instabilities
Multiplanar; involve abnormal internal or external rotation at tibiofemoral joint
Named based on relative direction in which the tibia subluxates on the femur
The axis of tibial rotation is shifted in the direction opposite that of the subluxation
Figure 6-24, page 223 Table 6-9, page 223
Rotational Knee Instabilities
Result when multiple structures are traumatized
Combined laxity of each structure is summed to mark degree of instability
Any injury to cruciate or collateral ligaments, joint capsule, IT band or biceps femoris may potentially result in rotational instability
Rotational Knee Instabilities
Signs and symptoms– “giving out”– Decreased muscle strength– Diminished performance– Lack of confidence in stability– Tests will often only produce positive results
under anesthesia
Anterolateral Rotatory Instability
Involves trauma to ACL and anterolateral capsule– LCL, IT band, biceps femoris, lateral meniscus,
posterolateral capsule
Anterior tibial displacement and internal tibial rotation
Many special tests to determine ALRI– Positive results should be referred to physician
ALRI
Slocum drawer test– ALRI (internal rotation) and AMRI (external
rotation)– Box 6-12, page 224
Crossover Test– Semifunctional; not as exact as other tests– Primarily for ALRI, but may be used for AMRI– Box 6-13, page 225
ALRI
Pivot shift test (lateral pivot shift)– Duplicates anterior subluxation and reduction that occurs
during functional activities in ACL-deficient knees– Box 6-14, page 226
Slocum ALRI test– Body weight used to fixate femur– Box 6-15, page 227
Flexion-rotation drawer test (FRD)– Stabilizes tibia, results in subluxation of femur– Box 6-16, page 228
Anteromedial Rotatory Instability
Injury involving ACL, MCL, and meniscus (more commonly lateral meniscus)
Variations of Slocum drawer test and crossover test
Posterolateral Rotatory Instability
Anterior displacement of lateral femoral condyle relative to tibia– Tibia externally rotates relative to femur– Amount of external rotation increase with flexion
Evaluative Findings– Table 6-10, page 229
External rotation test for PLRI– Box 6-17, page 230
Meniscal Tears
Result from rotation and flexion of knee, impinging the menisci between the articular condyles of tibia and femur
Lateral meniscus– More mobility = may develop tears secondary to
repeated stress McMurray’s test
– Box 6-18, page 231 Apley’s compression and distraction test
– Box 6-19, page 232
Meniscal Tears
Evaluative Findings– Table 6-11, page 233
“locking”, “clicking”, pain along joint line, “giving way”
Pain not be described if tear is in avascular zone
Osteochondral Defects
OCDs are fractures of the articular cartilage and underlying bone that are typically caused by compressive and shear forces
Medial femoral condyle most common; also lateral femoral condyle, tibial articulating surface, patella
Males affected more than females Figure 6-25, page 229
OCDs
Signs and symptoms– Masked by those of concurrent injury– Diffuse pain within knee– “locking”, “giving way”, “clunking”– Pain increased with weight-bearing activities– Increase in pain and decrease in strength in
closed kinetic chain vs. open chain
Wilson’s test – Box 6-20, page 234
OCDs
Conservative treatment– Modified activity
Surgical repair– Simple debridement or techniques to stimulate
fibrocartilage formation– Newer techniques – place newly grown articular
cartilage within defect, or transplant healthy cartilage form one area in knee to defect
Early protection phase in rehabilitation
Iliotibial Band Friction Syndrome
Friction between IT band and lateral femoral condyle
Occurs in sports that require repeated knee flexion and extension– Running, rowing, cycling
Bursa between IT band and lateral femoral condyle may become inflamed
IT Band Syndrome
Predisposing factors:– Genu varum – projects lateral femoral condyle
laterally, increasing friction– Pronated feet– Leg length differences– Conditions resulting in internal rotation alter angle
in which IT band attaches to Gerdy’s tubercle, increasing pressure at lateral femoral condyle
IT Band Syndrome
Evaluative Findings– Table 6-12, page 235
Noble’s compression test– Box 6-21, page 236
Ober’s test– Box 6-22, page 237
Treatment– Correct biomechanics, NSAIDs, modalities,
stretching, strengthening
Popliteus Tendinitis
Evaluative Findings– Table 6-13, page 238
Popliteus prevents a posterior shift of tibia on femur, running downhill places excessive strain on tendon
Figure-4 position – Figure 6-26, page 238 Treatment similar to other tendinitis
conditions
On-Field Evaluation of Knee Injuries
Equipment Considerations– Football pants– Knee brace removal
Figure 6-27, page 239
On-field History– Location of pain– Mechanism of injury– History of injury– Associated sounds and sensations– Associated neurologic symptoms
On-Field Evaluation of Knee Injuries
On-Field Inspection– Patellar position– Alignment of tibiofemoral joint
On-field Palpation– Extensor mechanism– MCL and medial joint line– LCL and lateral joint line– Fibular head
On-Field Evaluation of Knee Injuries
On-field Range of Motion Tests On-field Ligamentous Tests
– Valgus stress, varus stress, Lachman’s– Repeat after removing athlete from sideline
On-field Management of Knee Injuries
Tibiofemoral Joint Dislocations– Severe pain, muscle spasm, obvious deformity– Most occur with tibia sliding anteriorly over femur,
resulting in shortening of involved leg– Figure 6-28, page 241– Trauma to neurovascular structures = medial
emergency– Management – immobilization, verifying pulse,
shock, and activating EMS
On-field Management of Knee Injuries
Collateral and Cruciate Ligament Sprains– Compare bilaterally if possible– Remove from field in a non-weight-bearing
manner, if necessary– RICE, immobilization, referral, if necessary
Meniscal Tears– Evaluation based on athlete’s description of
mechanism of injury