Notas / Notes - Active Congress.......

JUEVES / THURSDAY
128
RESULTS MCKEEVER
• 51 Patients 55 knees 2 died 11 lost
• 40 Patients 44 knees Unicompartmental OA
• 39 medial 5 lateral 5-13 yr f/up(ave 8yr)
• 70% good/excellent
• 6 knees revised(11%) for pain
• 11 Knees with subsequent surgery
• Max of 50% failure
• Scoring system (demerit)
- 15 degree flex cont 60-80 degree arc - EXCELLENT
- 15 degree flex cont 30-60 degree arc - GOOD
» Scott et al JBJS 67A 1985
RESULTS MCKEEVER
• 61 McKeever’s (61 pts) 1971-78
• 5 year ave follow-up (2-13)
• 11 lost ; 11 poor result (18%)
• 7 revised
• Long rehab
- 6-8 weeks bivalve
- 3 weeks non weight bearing
- 3 months partial weight bearing
Emerson and Potter JBJS 67A 1985
RESULTS UNISPACER
• Hallock- AAOS 2002
• 120 patients
• 10% failure rate
• Steep learning curve
• Only 13 patients with greater than 1 year follow-up
• Not suitable for lateral side
Freedman- 2002
40% early failure rate
UNICOMPARTMENTAL KNEE
REPLACEMENT: MECHANICAL
CONSIDERATIONS
Albert Burstein
Professor Biomechanics. The Hospital for
Special Surgery (USA)
Since the earliest unicompartmental knee replacements were
developed, the mechanical problems they sought to solve
were the most difficult for any knee arthroplasty. Unlike total
knee prostheses, the unicompartmental knee does not enjoy
the luxury or creating its own alignment, stability, or kinematic
performance. The alignment of the unicompartmental knee
must conform to the proscribed geometry of the collateral
ligaments, the cruciate ligaments, and the articulation constraints
of the contra-lateral surface. The stability of the knee
after unicompartmental replacement should ideally mimic
the natural knee as all the existing ligamentous constraints
are still present, and the contra-lateral surface geometry is
functionally suited to these constraints. This condition brings
about two schools of thought. The first is to provide what
might be termed an unstable or highly mobile surface couple
consisting of a relatively flat tibial geometry. The second
school of thought provides articular surface geometries that
contribute to kinematic stability. Kinematic performance, a
combination of knee laxity, constraint and range of motion,
is controlled by articular surface geometry and placement.
The desired goal is to replicate the important aspects of the
original articulation, while at the same time not compromising
load transfer from the implant to the bone.
UNICONDYLAR KNEE
REPLACEMENT
David Dalury
John Hopkins Hospital. Baltimore (USA)
UKAs have enjoyed a minor resurgence in popularity with
increasing interest in mini-incision surgery. Newer implants,
improved instruments and better techniques have been
credited with the procedures new popularity. While the classic
UKA patient remains an elderly, thin, female with minimal
deformity there has been more focus on utilization of the
UKA as an alternative to HTO, and TKA in the younger patient.
Early results with the newer designed implants will be
reviewed.
UNICOMPARTMENTAL KNEE
ARTHROPLASTY WITH MOBILE BEARING
Keith R. Berend, MD
Joint Implant Surgeons, Inc., The Ohio State University,
Mount Carmel Health System,
New Albany, Ohio USA
Since the inception of unicondylar knee arthroplasty, clinicians
have debated the ideal indications for this conservative
procedure. Despite being reported more than 15 years ago,
many surgeons continue to follow the standard indications
outlined by Kozinn and Scott. These restrictive indications
and contraindications exclude patients who weigh >82 kg,
are younger than age 60 years, and who have more than