Clinical Evaluation of a Novel Technique of Impacting Osteochondral Grafts:
Center-Hole Technique vs. Standard Impaction
Ben B. Bedford, MD, Aruna M. Seneviratne, MD, Stephen J. Nicholas, MD
Nicholas Institute of Sports Medicine and Athletic Trauma (NISMAT), Lenox Hill Hospital, New York
Methods
Introduction
Osteochondral autograft and allograft transplantation is an
accepted treatment strategy for chondral and osteochondral
defects of the knee and shoulder. The purpose of this study was
to retrospectively review the clinical outcome and graft
morphology in patients with symptomatic osteochondral lesions
treated with osteochondral transplantation.
Hypothesis: The novel center-hole technique for graft impaction
will lead to similar clinical outcomes and will potentially protect
articular cartilage by promoting chondrocyte viability.
Threshold for chondrocyte
apoptosis
4.5 MPa
Between 2006 and 2009 five patients with
symptomatic chondral or osteochondral defects (four
knees, one shoulder) were treated with either
autologous osteochondral transplantation (two) or
osteochondral allograft transplantation (three). The
grafts were press-fit using either standard impaction or
the center-hole technique. Frozen allograft plugs were
used to backfill the autograft donor site in two knees.
Mean age at the time of surgery was thirty-one years.
The mean lesion size was 312 mm2. Clinical
assessment was performed postoperatively using the
International Knee Documentation Committee
(IKDC) score, activity of daily living of the Knee
Outcome Survey (ADL) score, and Short Form-36
(SF-36) at most recent follow-up. Magnetic resonance
imaging was used to evaluate the morphologic and
signal characteristics of the implanted grafts and the
surrounding cartilage. Standard statistical methods
using a paired Student’s t-test were used to analyze the
data.
Standard
Distribution of Force
Center Hole
Five patients met the study criteria with a mean
duration of follow-up of 15.6 months (range, four to
thirty-one months). The mean preoperative IKDC
score was 61.2 ± 17.5 and improved to 77.3 ± 22.3
(p= .016). The mean preoperative ADL score was 73
± 9.3 and improved to 88.5 ± 10.3 (p=.008). The
mean SF-36 score also improved from 83.4 ± 4.6 to
90.7 ± 5.9 (p=.013). At a mean follow-up of 15.8
months cartilage sensitive MRI demonstrated a flush
plug appearance in all patients and osseous trabecular
incorporation in 75% of patients. The graft cartilage
had preserved thickness and was isointense to
surrounding cartilage in all patients. With the
exception of increased temporary bone edema in 50%
of patients, the graft properties were similar in those
press-fit with the center-hole technique to those
treated with standard impaction.
Osteochondral transplantation is an effective treatment
for osteochondral defects in the knee and shoulder. In
our series there was a significant improvement in all
three mean clinical outcome scores. MRI can be a
valuable tool for postoperative evaluation of graft
cartilage and osteointegration. On MRI the centerhole technique led to increased signal within the bone.
This resolved on subsequent MRI and may not have
any important clinical significance. From a technical
standpoint, this technique allows greater control of the
graft during insertion. Center-hole technique is a
viable alternative to standard impaction resulting in
similar clinical outcome scores, while potentially
improving long term graft survival due to increased
chondrocyte viability at the time of implantation.
MRI T2 Mapping Assess Collagen Orientation
Orange = Short T2 values (collagen perpendicular to subchondral plate)
Yellow = Longer T2 values (more random collagen orientation)
Correlates with polarized light microscopy
Standard
Acknowledgments
Center
Hole
Live/Dead Staining of In-Vitro section of Hyaline Cartilage
Red = Dead Chondrocytes
Green = Live Chondrocytes
Standard Technique
Results
Conclusions
Center Hole Technique
Screw is placed in center of graft
Then impacted into recipient site
Screw removed
Dr. Michael Vazquez
Additional Information
www.nismat.org
www.nyorthodoc.com
www.lenoxhillhospital.org