osteoarthritis of knee joint

Dr. Anshu Sharma

Knee is a complex synovial joint formed between femoral condyles, tibial condyles & patella.

Stabilized by variety of ligaments.

Active movement at the knee are Flexion, Extension, Medial rotation & Lateral rotation.

The knee joint has no inherent stability rather it is provided by the surrounding ligaments and muscles.

The ligaments about the knee include the collateral ligaments and the cruciate ligaments.

The medial and lateral collateral ligaments prevent valgus and varus stresses, respectively.

The anterior and posterior cruciate ligaments prevent anterior and posterior tibial translation on the femur and secondary restraint to rotation.

Fibro-cartilagenous medial and lateral meniscus provides stability and shock absorption , especially with axial loading.

Osteoarthritis is a degenerative joint disease characterized by destruction of Articular cartilage.

More common than Hip OA in Asian population.

Old age,

Female sex,

Obesity,

Infection,

Trauma,

Intra- articular fractures,

Ligament or meniscus tears.

Indian habits : cross-leg sitting & squatting.

In OA disease process usually begins in Antero-medial compartment of knee.

Fibrillation of articularcartilage due to loss of water.

Destruction of articularcartilage.

Bone surfaces come in direct contact during joint movements leads to erosion.

Sclerosis, subchondralmicrofractures and cysts formation.

New bone & osteophyteformation.

- Pain : Steady/intermittent. - Stiffness : following periods of

inactivity, such as sleep or sitting.

- Swelling of joint.- Tenderness.- Crepitus : Crunching feeling or

sound of bone rubbing on bone- Locking. - Limitation of movements.- Deformity : Varus or Valgus.

- X-Ray Views:--Anteroposterior View (weight bearing)-Lateral view,-Notch patellar views (Sunrise view)

-Findings:--Joint space narrowing

Medial tibiofemoral joint space narrowing Patellofemoral joint space narrowing Lateral joint space narrowing to lesser

extent.-Osteophyte formation,-New subchondral bone formation,-Tibia lateral subluxation.

The Mechanical Axis of the lower limb is a line extending from the center of the hip joint to the middle of the ankle joint.

In a healthy, well aligned knee joint, the mechanical axis passes through the middle of the knee.

Only when the mechanical axis passes through the center of the knee joint, the stresses on the knee joint surfaces are uniform in all areas of the joint and well balanced.

In many knee joint diseases, the mechanical axis is disturbed and does not pass through the center of the joint.

This disturbance results in the overload of distinct areas of the knee joint leading to their damage.

NORMAL VARUS DEFORMITY

Treatment directed at symptoms and slowingprogress of the condition.

Goals: 4 R’s Relieve pain Restore function Reduce disability Rehabilitation

EARLY Treatment PHYSIOTHERAPY LOAD REDUCTION ANALGESICS

INTERMEDIATE Treatment JOINT DEBRIDEMENT AUTOLOGOUS CHONDROCYTE GRAFTING REALIGNMENT OSTEOTOMY

LATE Treatment ARTHROPLASTY ARTHRODESIS.

Non pharmacologic therapy Patient’s education

Use of assistive devices

Weight loss

Physical therapy

Occupational therapy

Pharmacologic therapy NSAIDS

Glucosamine sulphate

Intra articular Corticoteroids

Intra articular Hyaluronic acid.

Arthroscopic joint debridement, Chondrocyte transplantation, Proximal tibial osteotomy, Distal femoral osteotomy, Total knee arthroplasty, Arthrodesis.

PRINCIPLE:

In patients with unicompartmental O.A. of knee it causes “unloading” of involved joint compartment by correcting malalingnment & redistributing the stresses on the joint.

INDICATIONS:-

1. Pain & disability interfering high demand employment,

2. Radiographic evidence of involvment of 1 compartment with valgus/varus deformity,

3. Good muscle strength,

4. Good preipheral vascular status,

5. Ability of the patient to use crutches after operation and motivation to carry out a rehabilitation programme.

CONTRAINDICATIONS:-

Narrowing of lateral compartment,

Lateral tibial subluxation of more than 1cm,

Medial compartment bone loss of> 2-3 cm,

Flexion contracture of >15°,

Knee flexion of < 90 ° ,

More than 20 ° of correction needed,

Inflammatory arthritis,

Peripheral vascular disease.

Lateral closing wedge osteotomy,

Medial opening wedge with iliac crest bone graft and rigid fixation,

Dome or Barrel Vault osteotomy,

Medial opening hemicallotasis described by Turi et al., uses an external fixator to distract the osteotomy site gradually.

Techniques for valgus-producing high tibial osteotomy. A, Lateral closing wedge. B, Medial opening wedge. C, Dome osteotomy.

-Described by Coventry et al.,

-Advantages:

-It is made near the deformity

-It is made through cancellous bone, which heals rapidly,

-It permits the fragments to be held firmly in position by staples or by rigid fixation devices,

-It permits exploration of the knee through the same incision.

-Disadvantages:-Recurrence of deformity specially when alignment

was not overcorrected to at least 8* of valgus and patient is overweight.

-Limb shortening-Nerve injury-LCL laxity-Patella Baja-Delayed union or non-union.

-More recently, calibrated cutting guides, rigid internal fixation devices, and early mobilization have produced improved results and low complication rates after lateral closing wedge osteotomy.

If tibia is 57 mm wide, length of wedge=degrees of correctionOR

Length = Diameter of tibia X 0.02 X Angle

Measure the amount of correction needed to achieve normal angle then additional 3 to 5 degree of overcorrection is added.

INCISION Positioning transverseosteotomy guide

Placement of oblique osteotomy guide &

performing osteotomy

Application of compression clamp

& L- plate

Completion of osteotomy requires disruption of proximal tibia fibular joint or removal of infero medial portion of fibular head.

After osteotomy fragment is fixed with plate and screws.

Postoperative care:

CPM is started immediately after surgery in recovery room, usually from 0 to 30* of flexion, progressing 10* each day.

Ambulation is begun on 2nd post op day with use of crutches and 50% weight bearing is allowed for first 6 weeks.

Muscle strengthening and ROM exercises also are begun on 2nd post op day.

Full weight bearing is allowed after 6 weeks.

Described by Hernigou et al.,

Require:

-Use of osteotomy jigs,

-Iliac crest bone graft ,

-Rigid plate fixation.

Recommended if involved extremity shortening is 2cm. or more.

Indicated in patients with laxity of MCL or combined ACL deficiency.

A tourniquet is used. The skin incision was

placed vertically, on the medial side of the tibia curve to the proximal and dorsal side.

The periosteum was cut and partially stripped .

K-wire was drilled under direct fluoroscopic control in an oblique manner and at an angle to the tibial axis aiming for the upper part of the fibular head.

When satisfactorily placed, the osteotomy was performed using an oscillating saw for the first part and finished using a chisel under fluoroscopic control.

Great care was taken not to damage the lateral cortex.

The tibia was manually wedged to the point of desired correction, and the osteotomy plate was positioned and fixed.

The osteotomy gap was then filled with iliac crest bone graft.

With the principle of the Locking Compression Plate (LCP) system with angular stable screws locked within the new TomoFix plate, anatomically designed for the medial high tibial valgus correction, stable fixation of the osteotomy without bone grafts or bone substitutes may be achieved.

The plate functions like a bridging internal fixator .

Difficult exposure,

Fibular osteotomy required,

Higher union rate

Fixation covered with soft tissue,

Short duration of immobilization postoperatively.

Easy exposure,

No fibular osteotomy required,

Relatively unstable so rigid fixation is must,

May increase MCL tension,

Less chances of nerve injury.

Schwartzman After tibial osteotomy Ilizarov fixator.

Advantages :

• More reliable healing,

• Less chances of patella baja,

• Less bone loss,

• Ability to translate distal fragment to correct mechanical axis.

Disadvantages :

• Cumbersome, poor patient acceptance,

• Pin loosening,

• Pin site infection and close follow up is require.

Ilizarov method

Turi et al Dynamic uniplanar external

fixator after an opening wedge osteotomy.

At 7th Post operative day, the fixator is distracted 0.25mm four times a day until desired correction is obtained.

It is a slow distraction at the osteotomy site and hence obviates the need of bone grafting.

Position the fixator over the leg to check the position of the pin clamps,osteotomy site and hinge

Osteotomy site is below the tibial tuberosity

Make longitudinal incision just medial to tibial tuberosity up to 3-4 cm

Position of the fixator over the lateral tibial cortex at the level of osteotomy

Fixator secured with k-wires Proximal fixator pin inserted

Medial and lateralproximal fixator pins

Distal fixator pin placed

Osteotomy guide attached Series of holes drilled at osteotomy site

Holes connected with osteotomy Distraction of osteotomy

Passive motion has been started immediately after surgery.

Ambulation is begun on 2nd day, allowing weight bearing to tolerance with crutches.

Seven day after surgery, instruct the patient to distract the fixator 1 mm/day.

After appropriate correction is achieved, fixator is locked.

The fixator is removed after solid union is achieved.

Opening Wedge - Orthofix

Described by MAQUET.

Determine the angle of correction.

Midline vertical incision.

Curved line is marked on bone with its dome just above tibial tuberosity.

Multiple small drill holes made over this line.

Two k-wires inserted parallel to each other on either side of osteotomy.

Complete the osteotomy using osteotomy

Distal fragment is rotated until desired angle subtend by wire.

Fix the osteotomy using staples or plate. -Less commonly used.

To be a more technically demanding operation because of the challenges of creating a curved osteotomy and avoiding iatrogenic trauma to the patellar tendon.

-Advantage of intraoperative flexibility, which allows the surgeon to achieve the precise amount of desired angular correction.

-Dome osteotomy permits concomitant anterior translation of the tibial tubercle, which may alleviate associated patellofemoral disease.

HTO: Problems of conversion

• Prior incisions,

• Hardware ,

• Joint line distortion,

• Malunion/ nonunion,

• Patella baja,

• Offset tibial shaft,

• Retropatellar tendon

adhesions,

• Peroneal palsy,

• Infection.

1. HTO is a very useful option in young patients for unilateral OA,

2. Good Relief of pain can last per ten years or longer,

3. Less expensive,

2. Short learning curve.

COVENTARY TECHNIQUE.

Indicated in active patients younger than 65 years with valgus angulation <15* or plane of knee joint deviates from the horizontal by more than 10*

Indicated when distal femoral malunion which leads to unicompartmental arthritic changes.

TKR following this will be difficult due to:

-Exposure difficulty from scarring,

-Difficulty in hardware removal.

-Determine the size of wedge to be removed,-Establish the angle of plate insertion,-Osteotomy done and plate is fixed by screw.

SUPRACONDYLAR V -OSTEOTOMY

TKR is essentially a surface replacement of the articulating surfaces of femur, tibia and patella.

Soft tissue balancing is absolutely critical for long term success of the surgery.

Bony resection is aimed at achieving the normal mechanical axis of the lower limb.

1. The restoration of mechanical alignment,

2. Preservation (or restoration) of the joint line,

3. Balanced Ligaments

4. Maintaining or restoring a normal Q angle.

Fergussen (1860) resection arthroplasty

Verneuil (1863-1921 ) performed first interposition arthroplasty using joint capsule followed by others and they used muscles, fat & fascia and pig bladder.

1940s- First artificial implants were tried when molds were fitted in the femoral condyle.

Walldius (1950)- Combined femoral and tibial articular surface replacement appeared as simple hinges.

In 1971, Gunston importantly recognized that the knee does not rotate on a single axis like a hinge, but rather the femoral condyles roll and glide on the tibia with multiple instant centers of rotation. His polycentric knee replacement had early success with its improved kinematics over hinged implants but was unsuccessful because of inadequate fixation of the prosthesis to bone.

John Insall(1973), designed total condylar prosthesis at the hospital for special surgery and this desighn is basically the model used today.

This was a prosthesis made of three components which would resurface all three surfaces of the knee - the femur, tibia and patella.

Cobalt chrome alloy femoral component,

Cobalt chrome alloy or Titanium tibial tray,

UHMWPE tibial bearing component

UHMWPE patella component

(A) Unconstrained:-

Most common type, used for uncomplicated knee problems, artificial components inserted into the knee are not linked to each other, have no stability built into the system, depends on the person’s own ligaments and muscles. Cruciate retaining

Cruciate substituting

Mobile bearing knees

(B) Constrained (Hinged):Rarely used as a first choice, knee joint linked with a hinge, used when knee is highly unstable, useful in severely damaged, it is not expected to last as long as other types.

ConstraintAbility of prosthesis to provide varus – valgus and flexion –extension stability in presence of ligamentouslaxity/bone loss.

Intact PCLVarus def. < 10 Valgus def. < 15

Advantage1. Avoid post cam impingement/

dislocation,2. More closely resembles knee

kinematics,3. Bone preserving,4. Improved proprioception.

Disadvantage1. Tight PCL – Increased poly wear,2. Rupture PCL – flexion instability.

ABSOLUTE INDICATION-Previous patellectomy,-Inflammatory arthritis,-Deficient PCL

Cam and post mechanism Insert more congruent / dished

AdvantagesEasier to balance knee,More range of motion.

DisadvantagesCam jump,Post wear,Patellar clunk syndrome,Additional cut from distal femur.

INDICATION:-Global ligamentousdeficiency,-Hyperextension instability

Linked femoral and tibial components,

Tibial bearing rotates around yoke.

Disadvantages:-Aseptic loosening,-Large amount bone resection

Poly Rotates over tibial base plate.

Reduced poly wear.

No advantage of mobile bearing over fixed bearing.

Increased wear in undersurface of mobile bearing.

Cultural/patient expectation.

Cut more posterior condyle.

No difference in ROM – Mehin (JBJS 2010)

No difference in ROM Sumino (IntOrtho 2010)

Candidate for TKR Quality of life severely affected,

Continuous pain,

Restriction of ordinary daily activities,

Severe Varus or Valgus deformity,

Evidence of significant radiographic changes of the knee

Goal of TKR Pain relief,

Correction of deformity,

Restoration of normal limb alignment,

Restoration of a functional range of motion.

TKR is an elective surgery not an emergency so the patient’s condition should be optimized before performing surgery.

A Complete Medical and Surgical History,

Thorough Physical Examination,

Laboratory Work-up,

Anesthesia Assessment.

74

1. Standing full-length anteroposterior radiograph

from hip to ankle,

2. Lateral knee x ray,

3. Merchant’s view.

• The Incision:• An incision is made in the

midline and anterior aspect of the knee with the knee positioned in flexion, starting about 2 inches above upper pole of patella and distally to just medial to the tibial tubercle.

• The most common approach is the medial parapatellar approach.

The medial side of the knee is then exposed by removing the anteromedial knee capsule.

It is important to note that during exposure, no dissection is done in the subcutaneous tissue as it can compromise the vascularity of skin.

Pes anserinus insertion is not voilated.

• The leg is then extended and the patella is everted.

• The knee is once again flexed and the anterior horn of medial and lateral menisci and anterior cruciate ligament are removed.

• Posterior horns of menisci excised after the femoral and tibial cuts have been made.

• Subluxate and externally rotate the tibia.

• Expose the tibial plateau by partial excision of infra-patellar fat pad.

-Proximal Tibial cut:--A resection guide is attached to

front of tibia.

-The medial/lateral adjustment screw that is placed at the ankle is used to align the resection guide parallel with the tibia.

-To check alignment to the ankle an alignment rod is used.

-Direction of the saw cuts in 3D

AP tilt

LM tilt

-Upper end of tibia is resected.

The amount of tibial resection depends on which side of the joint is used for reference.

If unaffected side is taken as a reference, usually 8 mm cut is taken which is close to the size of the implant.

If affected side is taken as a reference, the amount of resection usually is 2mm or less.

Proximal tibial cut is taken perpendicular to its mechanical axis.

It is important to not to use extra-long cutting saw blade as it can go beyond the tibia to injure vital structures.

Four spikes are used for protection- medially for MCL, posteriorly for neurovascular bundle, two laterally for patella and patella tendon.

-Distal Femoral cut:- Femoral entry point is marked on the line joining the top of

the notch and the bottom of the trochlear groove (Whiteside line), 1cm anterior to the top insertion of the PCL.

A drill bit is used to create an opening in the femoral canal.

It is useful to lavage the medullary canal using long suction tube to reduce the incidence of fat embolism.

The valgus alignment guide is then used and attached to the IM reamer. It then rests and is secured on the distal femoral condyle.

A resection guide is attached to lower end of the femur 8-10 mm Osteo-cartilage surface is removed at 5 to 7 degree of valgus.

Another resection guide is anchored to end of femur and pieces of femur are cut off the front and back as directed by the miter slots in guide.

Then cuts are made to bevel the end of femur to fit implant.

• Then extension gap is measured.

• The anterior and posterior femoral cuts determine the rotation of the femoral component and shape of the flexion gap.

• Make a cut in 3 degrees of external rotation.

• Then flexion gap is measured.

• Box cut is taken to accommodate post cam mechanism of PCL substituting design.

The flexion and extension gaps must be roughly rectangular, equal and balanced.

If the extension gap is smaller then remove more bone from distal femoral cut surface.

If the flexion gap is smaller then remove more bone from posterior femoral condyles.

If the flexion and extension gaps are equal, but not enough space for prosthesis, remove more bone from proximal tibia.

Patellar Resurfacing:- First the patella is laterally

retracted with the articularsurface facing in the upward position.

Calipers are then used to determine the size of the patella along with the amount of bone that will be removed.

Patella must be at least 20mm thick and around 8-9mm of articular side of patella is resected using patellar clamps and saw.

The patellar peg holding guide is then placed on the resected patella and the peg holes are then drilled.

The patella button is usually cemented into place behind the patella.

Trial tibial, femoral and patellar components are inserted in place and trial poly component is fitted

The knee is then put through a series of motions to confirm normal movement, alignment and mediolateral stability.

The trial components are then removed after the correct fit is confirmed.

The joint is then irrigated with a pulse lavage.

The cement is then applied on the cut bone surfaces and the prostheses are then placed.

The femoral impactor is used to insert the femoral implant.

The tibial base impactor is used to insert the metal tibial base.

The patellar implant is secured with bone cement and held in place using the parallel patellar recessing clamp.

All excess cement is removed carefully.

The tibial polyethylene insert is seated and locked into place on the metal tibial base.

The knee is maintained in full extension so that the cement is pressuried.

The wound is thoroughly irrigated.

The tourniquet is then released and hemostasis is achieved using electro-cautery.

The wound is then closed in layers with or without suction drain and a compressive dressing is placed on the knee and knee brace applied.

Balance in both Coronal and saggitalplane.

Concave side –ligaments contracted –release

Convex side –ligaments stretched –Fill gap

HenriK Schroeder – Boesch – Ligament balancing in TKR

Posterior part tight in

extension

Anterior part tight in flexion

Grade 2A + 2B

With joint distracted multiple punctures are made in the length of the MCL using 18 gauge needle mounted on a syringe.

This can stretch the medial side by 1-2mm.

The number of punctures needs to be graduated as excessive punctures can make the MCL incompetent.

Usual number of punctures ranges from 10 to 15.

Remove all osteophytes,

Release posterolateralcapsule,

Pie-crusting of iliotibialband - Tight in extension,

Popliteus –Tight in flexion,

Release of LCL.

The main issue here is larger flexion gap and with tighter extension gap.

Balancing in such situations can be done by:

-Remove all osteophytes,

-Release posterior soft tissue from back of femur and tibia.

-Release PCL and use posterior stabilized implant.

-Increase distal femoral cut by 4-6mm.

The principle here is to very conservative about bone cuts.

The ligaments need to be preserved and routine release must not be done.

Constrained type of knee prosthesis must be kept ready.

Mc Pherson’s rule

Symmetric gap – Address tibia.

Asymmetric gap – Address femur.

Tight in Extension Tight in flexion

Symmetric gap Cut more tibia

Loose in Extension Loose in Flexion

Symmetric gap•Thicker poly •Tibial Metal augmentation

Extension good

Loose in flexion

Asymmetric gap

1. Increase size femoral component

2. Translate femoral component posterior

3. Use thicker poly and readdress as tight extension gap

Extension TightFlexion Good

AsymmetricGap

1. Cut more distal femur

2. Release posterior capsule

Extension GoodFlexion Tight

Asymmetric gap

1. Decreasefemoral component size

2. Recess PCL

3. Check slope of tibia

ExtensionLooseFlexion Good

Asymmetric gap

1. Distal femoral augmentation

2. Decrease femoral component size and thicker poly

Before closure it is mandatory for a surgeon to assess the movements of the knee joint.

The gliding of patella must be concentric on the femur without lateral tilt or lateral shift.

The patella gliding should be possible without the surgeon supporting the patella.

Patellar maltracking is most common complication.

To avoid this :-Maintain Q angle,-Proper rotation of components,-Maintain normal patellofemoral tension

Femur related factors:-

-Over sizing of femoral component,

-Not lateralizing the femoral component,

-Internally rotated femoral component,

-Excessive valgus position of femoral component.

Tibia related factors:-

-Medializing tibial component,

-Internal rotation of component,

-Too thick tibial component,

-Excessive valgus of tibial component.

Patella related factors:--Over stuffing of patella,-Placing patella more

laterally on the bone,-Placing the patella button

too low causing patella baja,

-Oblique cut on patella. Soft tissue related factors:--Tight lateral patellofemoral

bands and too lax medial retinacular structure,

-Infra-patellar contractures due to previous surgery (HTO, Fracture tibial plateau).

Resurfacing

Component loosening,

Clunk,

Fracture,

AVN.

Non resurfacing

Anterior knee pain,

May require second resurfacing.

Metal backed patella higher complications.

Patellar replacement does not guarantee painless Patellofemoral joint.

No significant benefit of patellar replacement.

Immediate Complications:--Neuro-vascular injury.

Early Complications:--Thromboembolism,-Infection,-Surgical wound related complications,-Malalignment and instability,-Patellofemoral complications,-Stiffness.

Late Complications:--Periprosthetic fractures,-Implant loosening,-Infection.

Different studies shows different results.

Ranawat et al (Clin Orthop Relat Res ) -95% at 15 years,

-91% at 21 years.

Gill and Joshi (Am J Knee Surg)-96% at 15 years,

-82% at 23 years.

Font-Rodriguez (Clin Orthop Relat Res)-98% at 14 years.

Precise surgical technique,

Sound implant design,

Appropriate material,

Patient compliance with rehabilitation.

Unlike total knee surgery UKA is Less invasive procedure

Replaces only damaged or arthritic parts i.e. in either compartments

UKA aims to resurface the diseased compartment without altering the kinematics of knee joint by load transfer or sacrificing the cruciate ligaments.

Clinically:--Pain and tenderness localized to medial joint line,-Flexion greater than 90*,-FFD less than 10*.

Radiologically:--Isolated medial compartment OA,-Varus deformity less than 15*,-Insignificant degenerative changes in opposite compartment.

Intra-operatively:--Correctable Varus deformity,-Intact ACL,-full thickness cartilage wear restricted to the anteromedial half of resected tibial plateau.

Absence of an intact ACL,

Inflammatory arthritis,

Crystal deposition induced arthritis,

Full thickness patellar cartilage loss,

Previous HTO,

Previous patellectomy,

BMI >30 kg/m2.

Small incision size,

Less bone removed,

Less blood loss,

Lower morbidity,

Quicker recovery & Early rehabilitation,

Shorter hospitalization,

Preservation of the ACL.

Inferior survivorship,

Error in proper placement of components,

Loosening,

Prosthetic wear,

Secondary degeneration of opposite compartment.

Erect

Postop xrays

Conversion of UKA to TKR

Indicated for severe disability esp. in young & active patient whose activity desire might severly limit the longevity of TKR, Infected TKR and Neuropathic joint.

Techniques of Arthrodesis:- External Fixation,- Intramedullary Nailing,- Plate Fixation.