Articular Cartilage Rehab

what are the typical mechanisms of arcticular cartilage injury?

direct or indirect blunt trauma, torsional loading, rapid loading

how can rapid loading cause articular cartilage injury?

muscle activation is too slow to absorb forces, no fluid movement within the cartilage to deal with the rapid load

what happens when the stress on cartilage reaches failure thresholds?

Rupture of the macromolecular framework, Cells are damaged, Subchondral bone is at risk for damage

is the articular surface always damage in a cartilage injury?

no, damage can be more deep

__________ occurs before other signs of cartilage injury

loss of proteoglycans

what age range do chondral fractures generally occur in?

skeletally mature people

what age range do osteochondral fractures generally occur in?

Skeletally immature people

how does the articular cartilage change as we age?

superficial zone decreases in strength, calcified cartilage-subchondral bone is fully mineralized, mechanical properties are different b/w regions

why does articular cartilage have limited potential for healing?

avascular, chondrocytes are immobile (cannot migrate to damage), limited proliferation of chondrocytes, no perichondrium

what is the repair response when the matrix of articular cartilage is damaged?

synthesis of new matrix and cell proliferation

what is the potential for healing after a matrix injury?

normal composition can be restored if there is enough intact matrix structure and cells remaining

what is the repair response when there is articular cartilage disruption?

Synthesis of new matrix cell proliferation, but new tissue does not fill defect

what is the repair response when there is articular cartilage and bone disruption?

Fibrin clot formation, inflammation, invasion of new cells, production of new chondral and osseous tissue

what is the potential for healing when articular cartilage or articular cartilage and bone are disrupted?

depends on lesion location/size, may or may not progress to degeneration

what are the clinical findings for a knee articular cartilage injury?

Intermittent pain and swelling, history of catching/locking, joint line tenderness

what is often the first diagnostic test if an acute osteochondral lesion is suspected?

plain radiograph

how is it determined whether an osteochondral legion requires surgery or not?

MRI, stability, possible arthrogram if still unsure

what is a grade 1 articular cartilage injury?

nearly normal, superficial lesions (fissures and cracks), soft indentation

what is a grade 2 articular cartilage injury?

abnormal, lesions extending down to less than 50% of cartilage depth

what is a grade 3 articular cartilage injury?

severely abnormal, lesions extending down to more than 50% of cartilage- can extend down to calcified cartilage layer

what is a grade 4 articular cartilage injury?

severely abnormal, lesions that extend down into the subchondral bone

how can an articular cartilage injury be treated?

rehab to adress impairments, surgery

what is a microfracture surgery?

drilling into cartilage defect to break out bvs and remnants to create better blood supply to promote healing

does microfracture lay down hyaline cartilage?

no

when is microfracture used? why

used on smaller lesions or during surgery for another problem, simple but not always effective

What is the ACI/MACI treatment

series of 2 surgeries, one which clears out defect and harvests cells which are then cultured, second implants newly grown cartilage sells into defect

what is the OATS procedure

osteochondral bone plug is take from a NWB surface of the knee and implanted into defect

what is an osteochondral mosaicplasty?

combines several smaller osteochondral bone plugs, used to fill larger lesions

when is fresh osteochondral allograft transplantation used?

on large deficits or failed prior surgery

how is treatment/surgery decided on for an articular cartilage injury?

location of lesion (femur vs patella), size of defect, demand of patient

what level of evidence are rehab protocols for articular cartilage injury based on?

expert opinion

what concepts are important for PT following an articular cartilage injury?

allow physiological healing, protect chondrocytes and matrix, avoid shear/compressive forces, minimize impacts

what do you need to understand about the lesion during rehab for an articular cartilage injury

Location, size, depth, containment, quality of surrounding tissue, duration of symptoms

what do you need to consider about the patient during rehab for an articular cartilage injury?

age, BMI, general health, activity level, specific goals, motivation

what do you need to consider about the surgery during rehab for an articular cartilage injury?

the type of procedure, tissue involvement, other procedures

what are the most common locations for knee articular cartilage lesions?

femoral condyle and patellar articular surface

what other locations can knee articular cartilage lesions occur but it is more rare?

trochlea and tibial plateau

what are the biological phases of cartilage maturation-proliferation?

proliferation, transition, remodeling, maturation

what interventions should be used during the proliferation phase of cartilage repair (4-6 weeks post surgery)?

protection, controlled PROM, limited joint loading, decrease swelling quad activation

what are the weight bearing precautions after a microfracture procedure for a deficit on the femoral condyle?

NWB up to 2 months (often less)

what are the weight bearing precautions after an OATS procedure for a deficit on the femoral condyle?

toe touch for 2 weeks, FWB by 4-6 weeks

what are the weight bearing precautions after a MACI/ACI procedure for a deficit on the femoral condyle?

toe touch for 2 weeks, then progress by 25% BW per week

what are the weight bearing precautions after a microfracture procedure for a deficit on the patella-trochlea?

toe touch WB for 1st 6 weeks

what are the weight bearing precautions after an OATS procedure for a deficit on the patella-trochlea?

immediate WB in licked brace

what are the weight bearing precautions after a MACI/ACI procedure for a deficit on the patella-trochlea?

toe touch immediately, partial week 2, 75% by weeks 3-4

does weight bearing occur sooner if the cartilage defect is on the femur or the patella? why?

patella, it bears less weight

how can knee effusion be monitored?

sweep test

what grade of swelling on the sweep test indicates that rehab program should not be progressed?

2+ or greater

how is a sweep test performed?

brush swelling up medially and then sweep down laterally, monitor movement on medial side to grade

what interventions should be used during the transition phase of cartilage repair (1-3 months post surgery)?

initiate joint loading, progress to FWB, normalize gait, LE strengthening

what interventions should be used during the remodeling phase of cartilage repair (criteria based progression)?

progress to functional activities, continue LE strengthening, advance to low impact

what ROM will engage/stress the lesion if it is on the femoral condyle?

30-70 degrees

what interventions should be used during the maturation phase of cartilage repair (criteria based progression)?

moderate-higher impact activities, full activity

what treatment options for articular cartilage rehab have moderate evidence based on the CPG

progressive knee motion, progressive WB, therapeutic exercises, neuromuscular estim/biofeedback

what is the goal of bracing for a knee articular cartilage injury?

to reduce articular contact stress in the most involved tibiofemoral compartment through a valgus or varus force

is there evidence for the effectiveness of bracing in articular cartilage injuries?

no

big picture goal of each phase of rehab protocol (1-4)

limited joint loading, joint reloading, functional activity progression, return to full activity

what warrant surgeon contact during rehab for an articualr cartilage injury?

sharp pain with locking or swelling

should you rely fully on time-based progression?

no, use criterion based progression (ROM, strength, effusion, pain, activity tolerance)

What extra precautions would be in place if a patient also had an osteotome?

PWB or WBAT for 4-6 weeks, no loading across osteotomy site for 4-6 weeks (to let bone heal)

what percentage of people with an articular cartilage procedure return to sport?

76

on average, how long does it take to return to sport after an articular cartilage procedure?

9 months

what procedure has the lowest return to sport?

microfracture

what procedure has the highest return to sport?

OAT

what long term deficits persist after an articular cartilage surgery?

quad strength deficits, gait deviations, deficits and asymmetries in function