TOTAL KNEE ARTHROPLASTY PRE OPERATIVE PLANNING IN DEFORMED KNEE

Dr amruth ram reddyPost graduate

VARUS KNEE• A FIXED VARUS DEFORMITY WITH A FLEXION CONTRACTURE IS

A LIKELY SCENARIO• HERE A PCL RESECTION IS TO BE PLANNED TO CORRECT LIMB

ALLINGMENT AND FLEXION CONTRACTURE• IN CASES WITH SEVERE CONTRACTURE INVOLVING EXTENSIVE

SOFT TISSUE RELEASE A CONSTRAINED CONDYLAR IMPLANT SHOULD BE AVILABLE

• A ROUTINE WEIGHT BEARING AP VIEW,LATERAL VIEW,TANGENTIAL PATELLAR VIEW SHOULD BE OBTAINED-THIS MAY SUGGEST PRE OPERATIVELY THE NEED FOR LATERAL RETINACULAR RELEASE

• BONE DEFECTS SHOULD ALSO BE NOTED BECAUSE PROSTHETIC AUGMENTATION OR BONE GRAFTING MAY BE REQUIRED.

IN SEVERE VARUS KNEESEVERE VARUS DEFORMITY IS COMMON IN OA KNEESSOURCE OF VARUS DEFORMITY IS ON TIBIAL SIDE OF THE KNEE JOINTROUTINE MEDIAN PARAPATELLAR ARTHROTOMY IS PLANNED LEVEL OF RESECTION IS MARKED ON ROUTINE PRE OPERAIVE RADIOGRAPH

THE LEVELOF RESECTION IS BASED ON THE INTACT LATERAL SIDETHE AMOUNT OF LATERAL RESECTION IS APPROXIMATELY 10MM INCLUDING ANY RESIDUAL CARTILAGETHE ANGLE OF RESECTION IS PERPENDICULAR TO THE LONG AXIS OF TIBIA AND HAS 3 TO 5 DEG POSTERIOR SLOPE.ON MEDIAL SIDE THERE WILL BE AN UNCAPPED BONE IF WE MAKE A CUT PERPENDICULAR TO MECHANICAL AXIS OF TIBIA

•A MARKING PEN IS USED TO OUT LINE THE UNCAPPED PORTION OF MEDIAL TIBIAL PLATEAU •THIS BONE IS REMOVED WITH AN ANGLE OF RESECTION PERPENDICULAR TO THE TIBIAL RESECTION•MCL SHOULD BE FREED FROM THIS PORTION OF BONE PRIOR TO ITS REMOVAL.THIS IT SELF IS SUFFICIENT TO RELEASE THE MCL,A SEPARATE FORMAL RELEASE OF MCL FROMTIBIA IS NOT REQUIRED AS IT CARRIES THE DANGER OF CATOSTROPHIC LOSS OF MEDIAL SUPPORT.

DISTAL FEMORAL RESECTION IS MADE IN 5 TO 7 DEGREES VALGUS AS IN A NORMAL KNEE(SINCE THE DEFORMITY IS IN TIBIA)DESPITE VARUS LIMB ALIGNMENT RESECTION USUALLY CALLS FOR MILLIMETER OR MORE REMOVAL OF MEDIAL DISTAL CONDYLE VERSUS LATERAL CONDYLE.THE RESECTION GUIDE WILL REST ON EBURNATED BONE MEDIALLY AND INTACT CARTILAGE LATERALLY.

• PATIENTS WITH SEVERE VARUS DEFORMITY HAVE HYPERPLASTIC MEDIALCONDYLES .

• THIS REQUIRES MORE EXTERNAL ROTATION FOR MAINTAINING FLEXION GAP SYMMETRY.

• RESIDUAL LATERAL LAXITY SHOULD BE KEPT IN MIND WHILE OPERATING A SEVERE VARUS KNEE.

• TO PREVENT THIS THE ANGLE OF FEMORAL AND TIBIAL BONE RESECTIONS SHOULD NO LONGER BE IN VARUS ALIGNMENT

• THE SECOND CRITERIA IS THAT THE LATERAL SIDE DOES NOT GAP OPEN WITH KNEE PASSIVELY RESTING IN SUPINE POSITON

• TO OVER COME THIS LATERAL LAXITY :

• INCREASE THE AMOUNT OF MEDIAL RELEASE AND USE A THICKER INSERT TO TIGHTEN THE LATERAL SIDE

• SECOND IS TO TIGHTEN THE LATERALSIDE BY ADVANCING THE LATERAL COLLATERAL LIGAMENT

SEVERE VALGUS DEFORMITY

• IT IS ASSOCIATED WITH LOSS OF LATERALCOMPARTMENT JOINT SPACE AND GRADUAL ATTENUATION OF MEDIAL COLLATERAL LIGAMENT

• PATELLOFEMORAL INVOLVEMENT IS COMMON• CHONDROCALCINOSIS IS A FREQUENT FINDING• IT USUALLY ARISES FROM FEMUR ,THE TIBIAL JOINT

LINE IS USUALLY IN NEUTRAL OR IN CLASSICAL 2 TO 3 DEG VARUS

• FEMORAL CONDYLE IS HYPOPLASTIC BOTH DISTALLY AND POSTERIORLY

• AS VALGUS PROGRESSES MCL BECOMES ATTENUATED –DEFORMITY INCREASES

• LATERAL FEMORAL CONDYLE ERODES LATERAL TIBIAL PLATEAU IN ITS CENTRAL PORTION

• PERIPHERAL ASPECT OF LATERAL PLATEAU REMAINS INTACT MAKING THE DEFECT CONTAINED ONE.

• COMPARING THIS WITH A VARUS KNEE EROSION OF MEDIAL TIBIALPLATEAU INVOLVES PERIPHERY OF PLATEAU-SO DEFECT IS NOT CONTAINED BUT STRUCTURALLY MORE SIGNIFICANT

VALGUS DEFORMITY COMES FROM FEMUR RATHER THAN TIBIA PATELLAR INVOLVEMENT IS COMMON

LATERAL FEMORAL CONDYLE HYPOPLASIA

• IN SEVERE VALGUS KNEE THERE IS HYPOPLASIA OF LATERAL FEMORALCONDYLE BOTH DISTALLY AND POSTERIORLY

• HERE IMPORTANT THING TO BE CONSIDERED IS NOT TO CUT THE MEDIAL CONDYLE CORRESPONDING TO THIS DEFICIENCY

• INSTEAD LATERAL SIDE MUST BE AUGMENTED.• IF EXCESSIVE DISTAL FEMORAL RESECTION IS

DONE TWO PROBLEMS MAY ARISE

• EXTENSION GAP CAN BE TOO LARGE

• JOINT LINE IS ELEVATED DISTORTING THE KINEMATICS OF COLLATERAL LIGAMENTS

• SO RESECTION SHOULD BE BASED ON NORMAL MEDIAL SIDE WITH AUGMENTATION LATERALLY USING CEMENT AND SCREWS

• ANGLE OF DISTAL FEMORAL RESECTION• It should be in 5 deg of valgus.• The less the over all valgus the less tension on

medial side.• How ever there is need for more lateral release to

balance the lax medial side• Otherreason is unless the surgeon enters the

medullary canal at this medialposition the valgus angle chosen on the cutting jig will result in few more valgus to the resections.

FLEXION CONTRACTURE ASSOCIATED WITH TKA

• FLEXION CONTRACTURES CAN RESULT FROM OSTEO ARTHRITIS,RHEUMATOID ARTHRITIS,POSTTRAUMATIC ARTHRITIS.

• OSTEOPHYTES DEVELOP IN INTERCONDYLAR AREA AND POSTERIORLY.

• THEY LIMIT EXTENSION BY SCARRING AND TENTING UP THE POSTERIOR CAPSULE

• IT IS IMPORTANT NOT TO OVER CORRECT THE FLEXION CONTRACTURE

• PREOPERATIVE MEASURES• MANIPULATION AND SERIAL

CASTING ARE USUALLY AMNEABLE TO PATIENTS WITH INFLAMMATORY ARTHRITIS WITH OUT OSTEOPHYTE FORMATION

• THIS METHOD IS NOT APPROPRIATE FOR OSTEO ARTHRITIC PATIENT WITH BLOCK TO EXTENSION

• VARIOUS OTHER MEASURES ARE PLANNED TO CORRECT THE FLEXION CONTRACTURE

• REMOVAL OF OSTEOPHYTES BOTH ANTERIORLY AND POSTERIORLY

• ADDITIONAL DISTAL FEMORAL RESECTIONS MAY BE NECESSARY FOR SEVERE CONTRACTURES

• DISTAL FEMORAL RESECTION SHOULD BE INCREASED BY 2 MM FOR EVERY EXTRA 15 DEG OF CONTRACTURE

• THE AMOUNT OF POSTERIOR TIBIAL SLOPE APPLIED TOTIBIAL RESECTION SHOULD BE ZERO RATHER THAN 3 TO 5 DEG

• EXTRA PROXIMAL RESECTION OF TIBIA WOULD BE APPROPRIATE IN PATELLA BAJA

• FINALLY PCL SUBSTITUTION WOULD BE HELP FUL TO RELEASE THE POSTERIOR STRUCTURES AND TO CORRECT THE POSTERIOR SUBLUXATION

• CONSTRAINED PROSTHESIS SHOULD ALSO BE READY IF SIGNIFICANT JOINT LINE ELEVATION LEADS TO FLEXION IN STABILITY.

• IN PATIENTS WITH BILATERAL CONTRACTURES BOTH SURGERIES SHOULD BE DONE SIMULTANEOUSLY OR WITH IN FEW WEEKS OF ONE ANOTHER

• OTHER WISE THERE IS SIGNIFICANT RISK OF CORRECTED KNEE REGRESSING TO LEVELOF FLEXION CONTRACTURE OF UNCORRECTED KNEE

• PATELLA BAJA:FLEXION CONTRACTURES ASSOCIATED WITH PATELLA BAJA-IF EXCESSIVE DISTAL FEMORAL RESECTION IS DONE THE CONDITION GETS WORSENED.

• JOINT LINE SHOULD BE LOWERED BY INCREASING THE NORMAL TIBIAL RESECTION TO INCREASE THE EXTENSION GAP

• THIS WILL LOOSEN THE FLEXION GAP• SURGEON SHOULD CONSIDER USING

ANTERIOR DOWN FEMORAL SIZING TECHNIQUE

• SLIGHTLY OVER SIZE FEMORAL COMPONENT IN AP DIMENSION

• IF THIS IS DONE INCREASED TIBIAL RESECTION HAS LESS INFLUENCE ON LOOSENING FLEXION GAP

TKA AFTER OSTEOTOMY

• TKA AFTER OSTEOTOMY IS A DIFFICULT PROCEDURE FOR FOLLOWING REASONS

• PRESENCE OF PRIOR INCISIONS • PRESENCE OF RETAINED HARDWARE• JOINTLINE ANGLE DISTORTION • MAL UNION,NON UNION• PATELLA BAJA• OFFSET TIBIAL SHAFTS• RELATIVE DEFICIENCY OF LATERAL TIBIAL PLATEAU

• VASCULAR SUPPLY AND LYMPHATIC DRAINAIGE ARE DOMINANT ON MEDIALSIDE

• LATERAL FLAP BEING MORE VULNERABLE• VULNERABILITY IS INCREASED WHEN LATERAL

RETINACULAR RELEASE HAS BEEN PERFORMED FOR LATERALPATELLAR TRACKING DAMAGING LATERAL SUPERIOR GENICULAR VESSELS

• IT IS ALWAYS BETTER TO USE A MEDIAL BASED FLAP• IF A SURGEON IS CONTEMPLATING TO USE A MEDIAL

INCISIO PARALLEL TOOLD LATERAL INCISION DELAYED TECHNIQUE OR SHAM INCISION CAN BE CONSIDERED.

RETAINED HARDWAREIT CAN BE RETYAINED IF IT DOES NOT CAUSE SYMPTOMS AND IS NOT LOCATED WHERE IT WOULD IMPEDE THE PLACEMENT OF COMPONENTSSCREWS AND STAPLES HAV TO BE REMOVED AT TIME OF ARTHROPLASTYPLATES HAVE TO BE REMOVED YHROUGH A LARGE SEPARATE INCISION BEST REMOVED 4 TO 6 WEEKS PRIOR TO ARTHROPLASTYIF THERE IS SUSPICION ABOUT CHRONIC LOW GRADE SEPSIS AT OSTEOTOMY SITE CULTURES CAN BE OBTAINED AT THE TIME OF HARDWARE REMOVAL

UPSLOPED JOINT LINE:

AFTER OSTEOTOMY THE MOST COMMON DISTORTION IN FLEXION EXTENSION PLANE IS CONVERSION OF NORMAL DOWN SLOPE OF TIBIA TO UP SLOPE OF VARYING DEGREETHIS DEMANDS A TIBIAL RESECTION AT 90 DEGREES TO LONG AXIS OF TIBIA IN SAGITTAL VIEWDOWN SLOPING MUST BE AVOIDED BECAUSE ABNORMAL AMOUNT OF BONE HAS TO BE RESECTED FROMPOSTERIOR ASPECT OF TIBIA AND RESULTANT DISTORTION OF KNEE KINEMATICS

POSTERIOR CRUCIATE LIGAMENT RETENTION VERSUS SUBSTITUTION

• PCL RETENTION:• ADVANTAGES:• BETTER RANGE OF MOTION(ROLL BACK FLAT TIBIAL

SURFACE)• MORE SYMMETRICAL GAIT• LESS FEMORAL BONE RESECTION IS REQUIRED• PCL NEEDS TO BE ACCURATELY BALANCED• JOINT LINE IS PRESERVED TO NEAR NORMAL LOCATION• THEY ALLOW PRESERVATION OF INTERCONDYLAR

BONE STOCK FOR FUTURE REVISION

• DISADVANTAGES • LATE ANTEROPOSTERIOR INSTABILITY OF PCL

RETENTION• THERE IS APPARENT NEED FOR MORE

FREQUENT LATERAL RELEASE FOR PATELLAR TRACKING

• THERE IS HIGHER INCIDENCE OF POLYETHYLENE WEAR

PCL SUBSTITUTION

• INDICATIONS:• ANKYLOSED KNEE• KNEE WITH SEVERE FLEXION CONTRACTURE• KNEE WITH CHRONIC PATELLAR DISLOCATION• POST PATELLECTOMY KNEE• IT PERMITS THE USE OF MODULAR STEMS FOR

ENHANCED FIXATION

DISADVANTAGES

• THERE IS HIGHER CONSTRAINT IN ARTICULATION MORE STRESS

• PATELLAR CLUNCK SYNDROME• REMOVALOF INTER CONDYLAR BONE STOCK • INABILITY OF POSTERIOR STABILIZED SYSTEM

TO ACCOMMODATE HYPEREXTENSION OF KNEE WITH OUT ANTERIOR IMPINGEMENT OF POST ON HOUSING.

PCL-retention or PCL-substitution ?

• PCL retaining prostheses:

– Better ROM (roll-back, flat tibial surface).– More symmetrical gait (stair climbing).– Less femoral bone resection is required.– PCL needs to be accuracy balanced.

• PCL substituting prostheses:

– Easier surgical exposure.– See-saw effect prevention.– Lower tibial polyethylene contact stress– Posterior tibial component displacement.– Patella clunk syndrome.

TIBIAL BONE STOCK DEFICIENCY

• IN SEVERE VARUS DEFORMITY THE MEDIAL TIBIAL PLATEAU IS ALWAYS DEFICIENT

• EXCISING THE BONE DOWN TO LEVEL OF MEDIAL DEFICIENCY REQUIRES UNACCEPTABLE AMOUNT OF LATERAL RESECTION

• HERE MEDIAL AUGMENTATION IS NECESSARY• RECONSTRUTION IS BASED ON TIBIAL JOINT

LINE BASED ON NORMAL LATERAL SIDE.

AT LEVEL OF THIS LATERAL JOINT LINE LINE IS DRAWN PERPENDICULAR TO LONG AXIS OF TIBIATHE DISTANCE FROM THIS LINE TO BOTTOM OF MEDIAL DEFICIENCY IS MEASURED10MM_NO AUGMENTATION IS REQUIRED15 MM OR MORE AUGMENTATION IS DEFINETLY NECESSARY10 TO 15 MM ADDRESSED ON CASE TO CASE BASIS

• Options for filling severe bone defects include modularmetallic wedges affixed to the undersurface of thecomponent.

• bone grafting, • custom prostheses. • Bone grafting is the most physiologic

alternative and is recommended for the younger patientS

TOTL KNEE ARTHROPLASTY FOLLOWING PATELLECTOMY

• The ideal patient for total knee replacement after patellectomy has had few other procedures on the knee for pain relief

• has gotten several years of satisfactory function fromtheir knee after patellectomy

• had the patellectomy for a patellar fracture• has good quadriceps function• has severe arthritis of the tibiofemoral joint.

When compared

The posteriorcruciate ligament prevents anterior translation of thefemur on the tibia during flexion, and the forces directedthrough the patellar tendon parallel to the PCL reinforcethis stabilizing function of the PCL .

• When comparedto nonpatellectomized patients, the patient can

• expect to have decreased range of motion• decreased quadriceps torque, • increased extensor lag, • Diminished ability to walk stairs, • more pain postoperatively.

Classification

1

2

3

4

CONSTRAINED PROSTHESISRESTRICT MOVEMENT IN ALL PLANES.•TWO TYPES•HINGED•NON HINGED

• HINGED ONES PERMIT MOTION ONLY IN SAGGITAL PLANE BUT RESTRICT IN CORONAL AND TRANSVERSE PLANES

• INDICATIONS:WHEN INSTABILITY IS SEVERE• AS A SALVAGE PROCEDURE WHEN OTHER TYPES HAV

FAILED.• COMPLICATIONS:HIGH INCIDENCE OF DEEP

INFECTIONS ,STEM BREAKAGE AND LOOSENING• NON HINGED:MOTION IS PERMITTED IN ALL PLANES BUT

NOT TO FULL EXTENT.• THESE ARE BALL AND SOCKET VARIETY.

SEMI CONSTRAINED PROSTHESIS

• Anterior-posterior stability.

• Two types:

– FREEMAN (a cylinder in a non conforming trough).

– INSALL (posterior stabilized knee).

• HERE THE JOINT SURFACE ALONE IS REPLACED• FEMORAL COMPONENTS ARTICULATE WITH

GROOVED TIBIAL COMPONENTS• THEY ARE SUB CLASSIFIED AS • PCL RETAINING• PCL SUBSTITUTION• PCL SACRIFICING DESIGN• COMPLICATIONS:LIGAMENTOUS LAXICITY,• DISLOCATION OR LATERAL TRANSLOCATION

SEMI CONSTRAINED PROSTHESIS

FreemanInsall

Non-constrained Prostheses

• Ideal implants.

• 5 degrees of freedom.

• Intact ligamentous system.

• PREFFERED IN PATIENTS WITH STRONG CRUCIATE LIGAMENTS

• IT SOLELY DEPENDS ON LIGAMENTS FOR STABILITY

• PRESERVATION OF PCL IS NECESSARY TO KEEP IT STABLE.

UNICOMPARTMENTAL ARTHROPLASTY

• IMPLANT IS USED TO REPLACE THE APPOSING ARTICULAR SURFACE OF FEMUR AND TIBIA OF EITHER MEDIAL OR LATERAL COMPARTMENT OF THE KNEE

• OTHER COMPARTMENTS ARE INTACT• INDICATIONS:• MEDIAL OR LATERAL TIBIOFEMORAL

DEGENERATIVE DISEASE IN PATIENTS WHOSE SYMPTOMS ARE REFRACTORY TO NON OPERATIVE MEASURES.

• CONTRA INDICATIONS:• INFLAMMATORY ARTHRITIS• RHEUMATOID ARTHRITIS• PSORIATIC ARTHRITIS• FLEXION CONTRACTURE OF 5 DEG OR MORE• PRE OPERATVE ARC OF MOTION LESS THAN 90

DEG• ANGULAR DEFORMITY OF MORE THAN 15 DEG • ACL DEFICIENCY

THANK YOU