Femoral Deformity and Deficiency in Complex Primary & Revision THA

David A. Mattingly, MD

Chief, Joint Reconstruction

Director, Otto E. Aufranc Fellowship

New England Baptist Hospital

Boston, MA

Femoral Deformity

• Developmental Dysplasia (DDH)

• Prior Surgery ( THR, Osteotomy )

• Post-traumatic

• Secondary Osteoarthritis– LCP; SCFE; Sepsis

• Coxa Vara & Coxa Valga

Femoral Deformity

• Small Femoral Canal– JRA; Dwarf; SED

• Large Femoral Canal– RA, AS, ETOH

• Paget’s Disease

Preoperative Planning

• Complete H&P– Leg lengths;N/V status

• X-Ray Evaluation

– AP Pelvis& Hip (Marker)

– Lauenstein lateral– CT; scanogram

*Identify equipment, prosthetic, osteotomy and bone graft requirements.

Femoral Deformity in THA

THA In Femoral Deformity

• Individualize Management

– Level of deformity

– Type of deformity

– Bone quality

– Patient factors

– Surgeon preferences

THA In Femoral Deformity

• Location of Deformity– Greater Trochanter– Femoral Neck– Metaphysis– Metaphyseal-Diaphyseal– Diaphysis– Distal to Diaphysis

Surgeon Requirements

• Proper Implant Selection

• Exact Implant Positioning

• Select Proper Surgical Approach

• Specialized Techniques– Trochanteric osteotomy– Corrective osteotomy– Leg lengthening

Treatment Options

1. Alter bone to fit prosthesis (osteotomy)

2. Select prosthesis to fit femur

3. Short implants or surface replacement to avoid more distal deformity

THA In Femoral Deformity

Greater Trochanteric Solutions

• Trochanteric Osteotomy (exposure)

• Trochanteric Advancement

THA In Femoral Deformity

Femoral Neck

• Varus

• Valgus

• Abnormal Version

THA In Femoral Deformity

Abnormal Version

• Cement small femoral implant in proper anteversion independent of anatomy

• Modular cementless implants

• Derotational osteotomy (subtrochanteric)

Implantation

Modular Advantages

• Goal: Avoid hard bearing impingement while maximizing range of motion.

• The ability to adjust femoral anteversion after cup placement has become increasingly important when using hard bearing implants where only neutral acetabular liners are available.

• The ability to adjust femoral anteversion after cup placement has become increasingly important when using hard bearing implants where only neutral acetabular liners are available.

THA In Femoral Deformity

Metaphyseal

• Cemented implants

• Uncemented modular

• Uncemented distal fixation

• Resect deformity, replace with implant

THA In Femoral DeformityMetaphyseal

CAUTION!!!!– Osteotomy

• Small fragment

• Fixation difficult

– Monoblock Metaphyseal Filling Implants• Fracture

• Poor fit

THA In Femoral DeformityMetaphyseal - Diaphyseal

• Mismatch

• Large canals

• Small canals

• Deformity

Enlarged Femoral Canal

Cement Cementless modularExtensively coated (stress shielding?)Reduction osteotomy

Difficult 1° THADifficult 1° THA

Small Patient

Difficult 1° THADifficult 1° THA

JRA, SED, dwarfAcet. & femoral dysplasiaTemplating criticalModular, custom,

mini componentsExpansion

osteotomy

Stenotic Femur

Avoid cement (stem too small)Cementless modularExpansion osteotomy

Difficult 1° THADifficult 1° THA

THA In Femoral Deformity

Diaphyseal

• Distal to implant

– Ignore deformity

– Treat independent of THA

THA In Femoral DeformityDiaphyseal

• Short implant or resurfacing

• Long implant / osteotomy

• Two stage (correct deformity, heal, THA)

THA In Femoral Deformity

• Individualize Management

– Level of deformity

– Type of deformity

– Bone quality

– Patient factors

– Surgeon preferences

Bone Defect Classification and Common Surgical Exposures

David A. Mattingly,MDChief, Joint Reconstruction

Director, Otto Aufranc FellowshipNew England Baptist Hospital

Boston,MA

Femoral Revision THA

Principles• Rotational implant stability

• Rigid implant fixation

• Stability with range of motion

• Restore Femoral Integrity & Continuity

• Prevent and/or Augment Bone Loss

• Restore Biomechanics (leg length; offset)

AAOS ClassificationFemoral Deficiencies

I. Segmental

II. Cavitary

III. Combined Segmental & Cavitary

IV. Malalignment

V. Stenosis

VI. Discontinuity

Paprosky Classification

Adequate Exposure in Complex THA

• Aids in Component Removal and Re-Insertion

• Accuracy of Instrument and Component positioning• Reduces incidence of fractures and perforations• Bone grafting procedures easier, faster, more accurate

Extensile Lateral

•Limitations: Post-column, Limitations: Post-column, retained trochanter, limp, retained trochanter, limp, H.O., lengtheningH.O., lengthening•retained trochanter, limp, H.O., lengtheningretained trochanter, limp, H.O., lengthening•Improved femoral exposureImproved femoral exposure•Reduces need for femoral fluoroscopyReduces need for femoral fluoroscopy•Perforations further weaken compromised femoral Perforations further weaken compromised femoral canalcanalIndicationsIndications

•Most complex THA’s Most complex THA’s •Less instabilityLess instability•SepsisSepsis•Postop irradiationPostop irradiation

Posterior

• Excellent exposure, minimal muscle damage, fast rehab

• Easy to make extensile

(soft tissue releases; femoral or trochanteric osteotomies)

• Retained trochanter limits distal canal access (>180 to 200 mm)

• Increased risk posterior dislocation

• Indications– Most acetabular/femoral revisions

– Posterior column plating

Complex THA

Trochanteric Osteotomy Advantages

• Allows extensile acetabular exposure (cages; posterior plating)

• Improves distal femoral access• Decreases fractures, perforations, varus• Assists in limb lengthening (>1.5 cm) and shortening

(5-10 mm)• Advancement improves M-F tension & stability

Extended Trochanteric OsteotomyIndications

• Well fixed implants (cement; porous)

• Well fixed cement

• Extensive Trochanteric Lysis

• Trochanteric Overhang/Varus Remodeling

• Malalignment Proximal Femur

Extended Trochanteric OsteotomyAdvantages

• Excellent exposure femur/acetabulum

• Atraumatic implant/cement removal

• Decreased perforations, fractures

• Deformity correction

• Protection of compromised trochanter

• Predictable healing

Distal Oblique Femoral Osteotomy

• Facilitates distal cement removal (>200 mm)

• Re-directional• 60o angle improves rotational

stability, maximizes contact, allows cerclage wiring

( Miller, et.al )

Retroperitoneal(Turner, Camer)

• Stage III - IV Protrusio

• Extruded medial cement

• IVP, venogram

• General, vascular surgeon