Achieving Leg Length Equality in THA Darwin Chen, MD Assistant - - PowerPoint PPT Presentation

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Feb 04, 2024 333 likes •577 views

Achieving Leg Length Equality in THA Darwin Chen, MD Assistant Professor Mount Sinai Medical Center Department of Orthopaedic Surgery Disclosures Monogram Orthopedics Consultant Conformis Medical advisory board, consultant

SLIDE 1 Darwin Chen, MD Assistant Professor Mount Sinai Medical Center Department of Orthopaedic Surgery

Achieving Leg Length Equality in THA

SLIDE 2 ▶ Monogram Orthopedics – Consultant ▶ Conformis – Medical advisory board, consultant

Disclosures

SLIDE 3

Leg Length Inequality

▶ One of the most vexing problems in THA ▶ Hard to define – Less than 1mm, 5mm,10mm? – Patient perception? ▶ Prevalence unknown ▶ 32-44% patients perceive LLD postop – Shortening < 10mm – Lengthening > 6mm Ranawat, J Arthroplasty 2001 Woolson, J Arthroplasty 1999 Hoffman, Orthpedics 2000 McGrory, JBJS 1995

SLIDE 4

Why is Leg Length Inequality Important?

▶ Abnormal gait ▶ LBP

, knee pain

▶ Nerve palsy ▶ Shoe wear ▶ Dissatisfaction ▶ Most common reason for litigation after THA! Clark, JAAOS 2006

SLIDE 5

Today’s Routine, Primary THA Should Be “Perfect”

▶ “…patients very soon become adjusted to 1cm of over-

lengthening.”

▶ A pain free THA isn’t good enough anymore ▶ Happy patient = – No pain

Well fixed implants

– Good function

Stability

– Equal leg lengths Sir John Charnley 1979

SLIDE 6

Preoperative History and Physical Exam

▶ Do your legs feel equal? ▶ PMHx – Spinal deformity/fusion – Prior trauma – Neuromuscular disorder – DDH ▶ Exam – Pelvic obliquity – Flexion contracture – Shoe modification

SLIDE 7

Preoperative History and Physical Exam

▶ True leg length – ASIS to medial malleolus ▶ Apparent leg length – umbilicus to medial

malleolus

*Preop* *Postop*

SLIDE 8

Templating is the Key to THA Success

▶ Goal – restore hip center of rotation, recreate offset, correct LLD ▶ Determine – Neck cut level – Acetabular position – Stem size and offset

SLIDE 9

Templating is the Key to THA Success

▶ Proper AP femur – 15º IR ▶ Proper marker ball placement 15º IR “Ball on ball” sign Improper marker ball placement

SLIDE 10

Templating is the Key to THA Success

SLIDE 11

Intraoperative Instability

▶ Don’t let intraoperative instability make you lengthen the

leg…look for other sources!

SLIDE 12

Posterior Approach – LLD Assessment

▶ Knee/heel assessment – Subjective, dependent on leg shape, pelvic position – Feel before neck cut, compare with template – Compare with trials ▶ “Shuck” test – Unreliable – Dependent on relaxation, soft tissue quality/contractures

SLIDE 13

Posterior Approach – LLD Assessment

▶ “L to C” - lesser trochanter to center of femoral head

SLIDE 14

Posterior Approach – LLD Assessment

▶ Bent Steinmann pin Mcgee, Scott, CORR 1985

SLIDE 15

Posterior Approach – LLD Assessment

▶ Calipers/tools

SLIDE 16

Direct Anterior Approach – Improved Leg Lengths?

▶ Trans-ischial or trans-teardrop line

SLIDE 17

Direct Anterior Approach – Improved Leg Lengths?

▶ Off-table, direct assessment K Berend

SLIDE 18

Direct Anterior Approach – Improved Leg Lengths?

▶ Overlay method J Matta

SLIDE 19

Does Advanced Technology Help?

$$$

SLIDE 20

Does Advanced Technology Help?

June 2015 “Robot-assisted posterior THA, fluoroscopy-guided anterior THA, and conventional posterior THA did not differ in obtaining minimal LLD. All three techniques are effective in achieving accuracy in LLD.”

SLIDE 21

Conclusions

▶ Preoperative templating is critical to restoring leg length and offset ▶ Posterior – lesser to center, calipers, pins, knee/heel ▶ Anterior – fluoroscopy, overlay, direct supine assessment ▶ A robotic/navigation system can help but is unnecessary and adds

excessive cost

SLIDE 22

Thank You

Darwin Chen, MD Assistant Professor Mount Sinai Medical Center Department of Orthopaedic Surgery