Patellar

7/23/2019 Patellar

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Patellar (Kneecap) Fractures

Because your kneecap (patella) acts like a shield for your knee joint, it can easily be broken.

Falling directly onto your knee, for example, is a common cause of patellar fractures.

hese fractures are serious injuries and often re!uire surgery to heal. "#er the long term, theymay cause arthritis in the knee.

$natomy

he patella is a small bone located in front of your knee joint % &here the thighbone (femur)

and shinbone (tibia) meet. 't protects your knee and connects the muscles in the front of your

thigh to your tibia.

he ends of the femur and the undersides of the patella are co#ered &ith a slippery substance

called articular cartilage. his helps the bones glide smoothly along each other as you mo#e

your leg.

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tatistics

Patellar fractures account for about * of all fractures. hey are most common in people &ho

are + to - years old. en are t&ice as likely as &omen to fracture the kneecap.

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ypes of Patellar Fractures

Patellar fractures #ary. he kneecap can crack just slightly, or can be broken into many

pieces.

$ break in the kneecap can happen at the top, center, or lo&er part of the bone. ometimes,

fractures occur in more than one area of the kneecap.

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his x/ray of the knee taken from the side sho&s a patella that has been fractured in three places.

Stable fracture. his type of fracture is nondisplaced. he broken ends of the bones meet up

correctly and are aligned. 'n a stable fracture, the bones usually stay in place during healing.

$ #ertical, stable fracture.

his x/ray of the knee taken from the front sho&s the faint line of a #ertical, stable fracture of the patella.

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Displaced fracture. 0hen a bone breaks and is displaced, the broken ends are separated and

do not line up. his type of fracture often re!uires surgery to put the pieces back together.

$ trans#erse fracture &ith some displacement.

his x/ray of the knee taken from the side sho&s a significant gap (displacement) bet&een the broken pieces of the patella.

Comminuted fracture. his type of break is #ery unstable. he bone shatters into three or

more pieces.

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$ comminuted fracture of the patella.

Open fracture. 'n this type of fracture, the skin has been broken and exposes the bone. hese

injuries often in#ol#e much more damage to the surrounding muscles, tendons, and

ligaments. "pen fractures ha#e a higher risk for complications and take a longer time to heal.

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1ause

Patellar fractures are most commonly caused by a direct blo&, such as from a fall or motor

#ehicle collision. he patella can also be fractured indirectly. For example, your thigh

muscles can contract so #iolently that it pulls the patella apart.

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ymptoms

he major symptoms of a patellar fracture include pain and s&elling in the front of the knee.$dditional symptoms include2

• Bruising

• 'nability to straighten the knee

• 'nability to &alk

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3octor 4xamination

$fter discussing your symptoms and medical history, your doctor &ill examine your knee.

he edges of the fracture can often be felt through the skin, particularly if the fracture is

displaced. 5our doctor &ill also check for hemarthrosis. his is s&elling deep inside the joint

that is usually a result of bleeding caused by the fracture.

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ests

6/rays are the most common and &idely a#ailable diagnostic imaging techni!ue. hey create

images of dense structures, like bone, so are particularly useful in sho&ing fractures. 6/raysare important for sho&ing front and side #ie&s of the fracture.

$lthough rare, a person may be born &ith extra bones in the patella that ha#e not gro&n

together. his is called bipartite patella and may be mistaken for a fracture. 6/rays help to

identify bipartite patella. any people ha#e bipartite patella in both knees, so your doctor

may take an x/ray of your other knee, as &ell.

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reatment

Nonsurgical Treatment











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'f the pieces of broken bone ha#e not been displaced by the force of the injury, you may not

need surgery. 1asts or splints may be used to keep your knee straight. his &ill keep the

broken ends in proper position &hile they heal.

5ou &ill not be able to put any &eight on your leg until the bone is completely healed. his

may take 7 to 8 &eeks, and perhaps longer. ost people use crutches during this period.

Surgical Treatment

'f the patella has been pulled apart (displaced), you &ill most likely need surgery. Fractured

patellar bones that are not close together often ha#e difficulty healing or may not heal. he

thigh muscles that attach to the top of the patella are #ery strong and can pull the broken

pieces out of place during healing.

Timing of surgery. 'f the skin around your fracture has not been broken, your doctor may

recommend &aiting until any abrasions ha#e healed before ha#ing surgery. "pen fractures,

ho&e#er, expose the fracture site to the en#ironment. hey urgently need to be cleansed andre!uire immediate surgery.

Procedure. he type of procedure performed often depends on the type of fracture you ha#e.

Before the surgery, your doctor &ill discuss your procedure &ith you, as &ell as any potential

complications.

$ figure/of/eight tension band holds the trans#erse fracture together.

• Transverse fracture. hese t&o/part fractures are most often fixed in place using

pins and &ires and a 9figure/of/eight9 configuration tension band. he figure/of/

eight band presses the t&o pieces together.

his procedure is best for treating fractures that are located near the center of the

patella. Fracture pieces at the ends of the kneecap are too small for this procedure.

Breaks that are in many pieces can be o#ercompressed by the tension band.

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$nother approach to a trans#erse fracture is to secure the bones using small

scre&s, &ires, and pins. 'n many cases, these &ires and pins &ill need to be

remo#ed about a year or t&o after the surgery.

• Comminuted fracture. 'n some cases, either the top or the bottom of the patella

can be broken into se#eral small pieces. his type of fracture happens &hen thekneecap is pulled apart from the injury, then crushed from falling on it.

Because the bone fragments are too small to be fixed back into place, they &ill be

remo#ed. 5our doctor &ill attach the loose tendon to the remaining patellar bone.

'f the kneecap is broken in many pieces at its center (and they are separated), your

doctor may use a combination of &ires and scre&s to fix it. :emo#ing small

portions of the kneecap may also ha#e good results. 1omplete remo#al of the

kneecap is a last resort in treating a comminuted fracture.

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:eco#ery

;o& long it takes to reco#er from a patellar fracture &ill depend on the se#erity of your

injury and &hether it re!uired surgery. 5ou and your doctor together can decide &hen it is

best to begin putting &eight on your leg, and return to &ork and other acti#ities.

Rehabilitation

0hether your treatment in#ol#es surgery or not, rehabilitation plays a #ital role in getting you

back to your daily acti#ities. Keeping your leg immobili<ed in a cast can result in kneestiffness and &eak thigh muscles. pecific exercises &ill help strengthen your leg muscles

and restore range of motion in your knee.

5our doctor &ill tell you &hen you can begin to put &eight on your leg. 'nitial &eight/

bearing exercise is usually limited to gently touching your toe to the floor. $s your injury

heals and your muscles strengthen, you &ill gradually be able to put more &eight on your leg.

LongTerm Outcomes

!rthritis. Patellar fractures often damage the articular cartilage that co#ers and protects the

underside of the bone. "#er time, this can lead to arthritis. e#ere arthritis occurs in aboutone out of e#ery four to fi#e patients. ild to moderate arthritis (chondromalacia patella) is

much more common.

"uscle #ea$ness. Permanent &eakness of the !uadriceps muscle in the front of the thigh is

another possible long/term problem. ome loss of motion in the knee, including both

straightening (extension) and bending (flexion), is also common. his loss of motion is

usually not disabling.

Chronic pain. =ong/term pain in the front of the knee is common &ith patellar fractures.

Lifestyle Changes



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5our doctor may suggest some lifestyle changes to protect your knee and pre#ent future

problems. hese may include a#oiding exercise acti#ities that in#ol#e repetiti#e deep knee

bending or s!uatting. 1limbing stairs or ladders should be a#oided, as &ell.

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Patellar