Conferencias

CONFERENCIAS
Meniscal Allografts: Where are We?
Thomas L. Wickewicz MD Rationale for Meniscus Transplantation

•Replace meniscal function: •Symptomatic relief of compartment overload •Forestall known sequelae of meniscal deficiency; chondroprotective •Augment stability especially medial meniscus
MENISCAL TRANSPLANTATION

•Two objectives

1) clinical improvement 2) meniscal function•What evidence exists that we actually achieve these objectives?
Basic science studies

•Human cadaver studies: •Animal studies:

meniscal transplants, if well positioned, can function biomechanically dog, rabbit generally demonstrate that the transplant is not chondroprotective

Subjective outcome measures

•Multiple studies •Multiple outcome measures •Generally:

improvement in pain notnecessarily improvement in function follow up interval not really an influence

Subjective data •Rueff et.al. Arthroscopy 2006 with ACL reconstruction – all with significant improvements •Sekiya et.al. Arthroscopy 2006 isolated lateral meniscal transplant-96% of patients improved

•Stone et.al. Arthroscopy 2006

succcess defined as no allograft removal-89% successful •Cole et.al. AJSM 2006half were isolated procedures- 90% normal or nearly normal on IKDC •Verdonk et.al. Knee Surg Sports Traumatol Arthrosc 2006 modified HSS score with significant improvement in all groups best when combined with osteotomy KOOS however revealed substantial disability •Noyes et.al. JBJB 2004 89% of patients rated the knee as improved Objective outcome measures MRI

•Generally: •At best, 50% ofstudied transplants in any given study meet criteria for normal or functioning menisci (normal
signal characteristics, normal position—not extruded—healed to periphery of native meniscus) Objective data Hommen et.al. Arthroscopy 2007 MRI showed shrinkage in all grafts 55% failure rate when second-look surgery and MRI data was added to Lysholm and pain score failures Verdonk et.al. Knee Surg SportsTraumatol Arthrosc 2004, 2006 MRI showed progression of cartilage degeneration in 65% of knees, and transplant extrusion noted in the majority of knees Stollsteimer et.al. Arthroscopy 2000 MRI showed shrinkage of all grafts von Lewinski et.al. Knee Surg Sports Traumatol Arthrosc 2007 radiographs and MRI showed advancement of degenerative changes Noyes et.al. JBJS 2004 meniscal allograftcharacteristics were altered in 30% and failed in 28%

•How do we reconcile this conflicting data? •Absence of clinical signs and symptoms
Does not equal

•Well healed, intact, functioning meniscus
My Current Indications for Meniscus Transplantation

•Minimal articular cartilage degeneration •No flattening of femoral condyle •Stable (or able to be stabilized) •Appropriate axial alignment

PatientEvaluation • consider four factors in any knee with cartilage injury: –Joint surface (hyaline cartilage/subchondral bone) –Ligament status –Alignment –Meniscal status •Many complex reconstructions require attention to more than one factor

•Collect relevant information:
–Careful history –Review operative reports, photographs

•Examination
–Gait (thrust?) –Alignment –Ligament status –Effusion–Other areas contributing (hip, spine, vascular)

•Imaging studies
–Plain radiographs: Standing AP at 0, PA at 40, lateral, Merchant –Bilateral hip-to-ankle alignment films –MRI with appropriate cartilage pulse sequences
•Assess remaining meniscus, hyaline cartilage, subchondral bone, joint architecture ( coronal images) –More sensitive techniques in the near future? T2 mapping, biomarkers,optical coherence tomography, indentation probes?? Are the symptoms due to early compartment overload from meniscus deficiency?? Combined Meniscus Transplant and Cartilage Resurfacing / Osteotomy

•Does resurfacing procedure make compartment suitable for meniscus transplant? •Resurfacing procedure for focal chondral defect seems reasonable •Osteotomy is not likely to make compartment suitable...