Knee injuries

Osteochondritis dissecans

-Etiology: partial or complete separation of articular cartilage and subchondral bone; causes include blunt trauma, skeletal/endocrine abnormalities, prominent tibial spine impinging on lateral portion medial femoral condyle, or patellar facet impinging on medial femoral condyle. 80% of fragments occur in lateral medial femoral condyle -Signs/Symptoms: aching pain, recurrent swelling, locking, possibly quadriceps atrophy -Management: children-rest and immobilization; adults-surgery (drilling to stimulate healing, pinning/bone grafts)

Loose bodies within the knee

-Etiology: result of repeated trauma, possibly stemmed from OCD, meniscal fragments, synovial tissue, or cruciate ligaments -Signs/Symptoms: fragments may become lodged, causing locking/popping; pain and sensation of instability -Management: if not surgically removed, can lead to conditions causing joint degeneration

patellofemoral stress syndrome

-Etiology: results from lateral deviation of patella while tracking in femoral groove; irritation of synovium; may be caused by tight structures, pronation, increased Q-angle, or insufficient medial musculature -Signs/Symptoms: tenderness of lateral patella, swelling, dull ache in center of knee, patellar compression will elicit pain and crepitus, apprehension when patella is forced laterally -Management: correct imbalances of strength and flexibility (avoid pronation, valgus, femoral anteversion); McConnel taping; lateral retinacular release if conservative measures fail

Osteochondral knee fx

-Etiology: shearing off of a piece of bone attached to anterior cartilage or cartilage alone. Twisting, sudden cutting, or being struck directly in the knee are common causes -Signs/Symptoms: snapping, knee giving way, immediate and extensive swelling (hemarthrosis-blood in a joint cavity), pain -Management: diagnosis confirmed by arthroscopic examination; surgery to replace fragment

Meniscal lesions

-Etiology: ---Medial meniscus is most often injured (ligamentous attachments, less mobile on top of tibia, more prone to disruption through torsional and valgus forces) ---Longitudinal, oblique, or transverse tears (tears in outer 1/3 more likely to heal) ---MOI: rotary force with knee flexed or extended -----squatting mechanism: posterior horn injury with excessive knee flexion -----cutting mechanism: medial injury due to MCL; lateral injury due to compression -Signs/Symptoms: effusion developing over a 48-72 hour period (less blood supply than ACL), joint line pain and loss of motion, sensations of locking and giving way, pain with squatting -Management: menisectomy rehabilitation allows partial weight bearing and quick return to activity; repaired meniscus will require immobilization and a gradual return to activity over 12 weeks

Bursitis

-Etiology: acute or chronic and recurring swelling ---Housemaid's knee: prepatellar bursa - continued kneeling ---Clergyman's knee: infrapatellar bursa - overuse of patellar tendon ---Breastroker's knee: pes anserine - overuse of tendons (sartorius, gracilis, semitendinosus) -Signs/Symptoms: inflammation, possible redness and increased temperature -Management: eliminate cause, RICE, NSAIDs; control swelling to avoid infection; aspiration if chronic

Osgood-schlatter disease & larsen Johansson disease

-Etiology: common in adolescents; ---OS=apophysitis at tibial tuberosity (develops bony callus, enlarging the tubercle; resolves with aging; common cause=repeated avulsion of patellar tendon) ---LJ=result of excessive pulling on inferior pole of patella -Signs/Symptoms: swelling, hemorrhaging, gradual degeneration of apophysis due to impaired circulation; pain with kneeling, jumping, running; point tenderness -Management: reduce stressful activity until union occurs (6-12 months); possible casting; ice before & after activity; isometrics

Peroneal nerve contusion

-Etiology: compression due to a direct blow or tension from excessive knee varus -Signs/Symptoms: pain and possible shooting nerve pain, numbness/paresthesia in cutaneous distribution (dorsal foot), generally resolves quickly (if not, could result in drop foot) -Management: RICE, return when symptoms resolve and no weakness is present

Acute patellar subluxation or dislocation

-Etiology: deceleration with simultaneous cutting in opposite direction (valgus, quads pull patella out of alignment). Lateral most common (smaller lateral femoral condyle, greater lateral pull by quadriceps, IT band) Osteochondral damage to patella or left condyle. Repetitive subluxation will impose stress to medial restraints ---Predisposing factors: large Q-angle, shallow femoral grooves, flat lateral femoral condyles, vastus medialis and ligamentous laxity with genurecurvatum and ER tibias, pronated feet, ER patellas -Signs/Symptoms: subluxation-pain and swelling, restricted ROM, TTP @ adductor tubercle; dislocation-total loss of function; articular cartilage may be torn (underside of patella) -Management: reduction performed by moving patella medially as knee is extended; immobilization for 4+ weeks, strengthening of all knee, thigh, and hip musculature; correct postural malalignments

patellar fx

-Etiology: direct or indirect trauma: forcible contraction (pull of tendon), falling, jumping, running -Signs/Symptoms: hemorrhaging and joint effusion; little bone separation with direct injury; indirect fractures may cause capsular tearing, separation of bone fragments, and possible quadriceps tendon tearing -Management: x-ray, RICE and splint, immobilized for 2-3 months

Baker's cyst

-Etiology: herniation of joint capsule into popliteal fossa due to joint effusion; more common in adolescents -Signs/Symptoms: swelling in popliteal fossa; may be painless -Management: treat conservatively (RICE & NSAIDs), aspiration of cyst if it becomes painful

Knee plica

-Etiology: irritation of the plica (generally, mediopatellar plica and often associated with chondromalacia) -Signs/Symptoms: recurrent episodes of painful pseudolocking, possible snapping and popping, pain with stairs and squatting, little or no swelling no ligamentous laxity -Management: RICE, NSAIDs, recurrent conditions may require surgery (not usually very successful)

Patellar tendinitis (jumper's & kicker's knee)

-Etiology: jumping or kicking places tremendous stress and strain on quadriceps tendon; sudden or repetitive extension (squats) -Signs/Symptoms: pain and tenderness at inferior pole of patella ---Three stages: 1) pain after activity; 2) pain during & after; 3) pain during & after (possible prolonged) and may become constant -Management: ice, phonoporesis, iontophoresis, ultrasound, heat; exercise; patellar tendon bracing; transverse friction massage

Injury to infrapatellar fat pad

-Etiology: lies between the synovial membrane and the patellar tendon. May become wedged between tibia and patella, irritated by chronic kneeling pressures or traumatized by direct blows -Signs/Symptoms: repeated injury causes hemorrhage and swelling and eventually scarring and calcification may develop. Pain below patellar ligament (esp. during knee extension); weakness, mild swelling, stiffness -Management: rest from irritating activities, heel lift (1/2 - 1 inch) or hyperextension taping

Chondromalacia patella

-Etiology: softening and deterioration of articular cartilage ---Possible abnormal patellar tracking: -----Genuvalgum -----ER tibias -----Foot pronation -----Femoral anteversion -----Patella alta -----Shallow femoral groove -----Increased Q-angle -----Laxity of quad tendon (holds patella in place) ---Three stages: -----1) swelling and softening of articular cartilage -----2) fissuring (breaking apart) of the softened articular cartilage -----3) deformation of surface of articular cartilage caused by fragmentation -Signs/Symptoms: pain with walking, running, stairs, and squatting; possible recurrent swelling; grating sensation with flexion/extension; pain at inferior border during palpation -Management: conservative (RICE, NSAIDs, isometrics, orthotics); surgery (can "clean out" but can't replace articular cartilage)

Patellar tendon rupture

-Etiology: sudden powerful contraction of the quadriceps; usually does not occur unless there has been an inflammatory condition over time of the knee extensor mechanism, causing tissue degeneration. ---Usually is torn from its attachment (quadriceps tendon ruptures from superior patellar pole; patellar tendon ruptures from inferior pole of patella) -Signs/Symptoms: patella moves upward toward thigh and defect is palpable; athlete unable to extend knee; considerable swelling with significant pain -Management: surgical repair; those using steroids should avoid intense exercise involving knee

Joint contusions

-Etiology: vastus medialis is frequently involved (locks knee in full extension) -Signs/Symptoms: ---Bruise of vastus medialis: severe pain, loss of movement, swelling & discoloration (due to tearing of muscle and vessels) ---Bruise of capsule tissue: often associated with muscle contusions and deep bone bruises ---Possible bleeding and irritation of synovial membrane, which will result in fluid effusion into the joint cavity. Repeated blows may cause chronic synovitis or arthritic sequela -Management: compression and cold, rest, gradual AROM exercises, return to activity with protective padding

Runner's knee

-General expression for repetitive/overuse conditions attributed to malalignment & structural asymmetries -IT Band Friction Syndrome ---Etiology: genuvarum or pronated feet; tight IT band ---Signs/Symptoms: pain localized at lateral femoral condyle and may radiate down lateral joint line to insertion on tibia. Increased symptoms with downhill running (increased pain at 30° flexion) ---Management: correction of malalignments, NSAIDs, orthotics, ice before & after -Pes Anserine Tendinitis/Bursitis ---Etiology: result of genuvalgum & weak vastii muscles; due to running on inclined surfaces (1 leg higher)

Unhappy triad/terrible triad

-MOI: valgus force with foot planted and foot in slight ER -Damage to MCL, ACL, & medial meniscus

Anterolateral (ALRI) rotary instability

-Static: ACL, LCL, postero- & anterolateral capsule -Dynamic: arcuate complex (popliteus, lateral gastroc, biceps femoris), IT band -Common MOI: lateral tibial plateau rotates anteriorly on femur; plant foot in IR & cut to same side (crossover) ---Structures damaged: anterolateral structures, compression of anterior horn of lateral meniscus and posterior horn of medial meniscus -Special tests: slocum IR test, pivot shift

Anteromedial (AMRI) rotary instability

-Static: ACL, MCL, postero- & anteromedial capsule, posterior oblique ligament (thickening of medial capsule - adductor tubercle → tibia and posterior joint capsule) -Dynamic: pes anserine muscles, semimembranosus and semitendinosus -Common MOI: medial tibial plateau rotating anteriorly on femur; valgus force (shifts axis laterally); plant foot in ER and cut in opposite direction (side cut) ---Structures damaged: anteromedial structures; compression of anterior horn of medial meniscus and posterior horn of lateral meniscus (posterior more commonly injured) -Special tests: slocum ER test (30° tibial ER)

Posterolateral rotary instability (PLRI)

-Static: PCL, arcuate complex, LCL, postero & anterolateral capsule, ACL -Dynamic: popliteus, lateral gastroc, biceps femoris -Common MOI: lateral tibial plateau rotates posteriorly on femur (tibial ER relative to femur); hyperextension and ER of tibia; direct blow to anteromedial knee ---Structures damaged: posterolateral stabilizers; ER of tibia causes lateral tibial plateau to drop off posteriorly -Special tests: ER recurvatum test; gravity ER test

Posteromedial rotary instability (PMRI)

-Static: PCL, posterior oblique ligament, MCL, postero & anteromedial capsule, ACL -Dynamic: medial hamstrings, vastus medialis oblique -Common MOI: medial tibial plateau rotates posteriorly on femur (tibial IR relative to femur); significant valgus force to anterolateral knee ---Structures damaged: posteromedial stabilizers (global instabilities - serious injury) -Special tests:gravity drawer

ACL sprain

-Straight Anterior Instability: most vulnerable with tibial ER/IR and knee valgus (greatest tension on ACL) ---Direct blow to posterior aspect of knee or extreme anterior shear force ---Hyperextension of knee (intercondylar eminence) - tension on anterior stabilizers, compression on posterior horns of menisci ---Special tests: anterior drawer, Lachman's, posterior drawer (r/o PCL) -Etiology: higher incidence in females, often involves damage to other structures (meniscus, capsule, MCL) ---Contact MOI: foot planted and ER with valgus force applied to lateral knee ---Non-contact MOI: sudden deceleration or change in direction, poor technique -----Knee typically close to full extension and may collapse into valgus (femoral ADD, IR) -----Hyperextension (may overstretch or cause impingement) -Signs/Symptoms: pop, severe pain, rapid swelling at joint line, large joint effusion and loss of ROM -Management: RICE, crutches; non-surgical may result in joint degeneration due to chronic instability

LCL sprain

-Straight Lateral Instability: direct blow to medial knee with knee flexed (direct), extreme varus force with tibial IR (indirect, cross-over cut) ---Structures: ---Tension on lateral stabilizers, peroneal nerve damage ("drop foot") ---Compression on lateral meniscus ---Special tests: varus test at 0° & 30° -Etiology: result of a varus force, generally with tibial IRSecondary injury: cruciate ligaments, IT band, meniscus (compression injury - medial) -Signs/Symptoms: pain, swelling & effusion over LCL, joint laxity with varus testing, irritation of peroneal nerve -Management: as described in MCL injury

MCL sprain

-Straight Medial Instability: direct blow from lateral side with knee flexed (direct) or extreme valgus force with tibial ER (indirect), side-step cutting (plant foot and cut to opposite side) ---Structures: -----Tension on medial stabilizers, medial meniscus -----Compression of lateral meniscus -----Patellar dislocation may occur secondary to valgus -----Potential damage to cruciate ligaments if severe ---Special tests: valgus test at 0° & 30° -GRADE I: ---Signs/Symptoms: little fiber tearing, stable valgus test, little or no joint effusion, some pain, relatively normal ROM and firm endfeel ---Management: RICE for 24 hours, crutches, cryokinetics, isometrics → SLR → bike & isokinetics, may need 3 weeks to recover -GRADE 2: ---Signs/Symptoms: complete tear of deep MCL, partial tear of superficial MCL. Laxity at 5-15° of flexion. Slight swelling, moderate to severe joint tightness with decreased ROM, pain along medial knee ---Management: RICE for 48-72 hours, crutches and/or bracing, modalities for pain, progression from isometric quadriceps contractions → CKC exercises and function progression activities -GRADE 3: ---Signs/Symptoms: complete tear of MCL, moderate swelling, immediate pain followed by ache, loss of motion due to effusion and hamstring guarding, positive valgus stress test ---Management: RICE, conservative vs surgery, limited immobilization and progressive weight bearing

PCL sprain

-Straight Posterior Instability: vulnerable after ACL has been torn and knee is in hyperextension ---MOI: posterior shear force over proximal tibia on a flexed knee -----Tension over posterior stabilizers -----Compression to anterior horns of meniscus ---Special tests: posterior sag/gravity drawer, posterior drawer -Etiology: most at risk in 90° knee flexion ("dashboard force" - ER setting) ---Most common MOI: fall on bent knee (tibia hits ground first) ---Can also be damaged as a result of a rotational force -Signs/Symptoms: pop in the back of the knee, tenderness and relatively little swelling in popliteal fossa, laxity with posterior sag test -Management: RICE, surgery requires 6 weeks immobilization in extension