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Orthop J Sports MedOrthop J Sports MedOJSspojsOrthopaedic Journal of Sports Medicine2325-9671SAGE Publications Sage CA: Los Angeles, CA 10.1177/2325967118S0013710.1177_2325967118S00137ArticlePreoperative Outcome Scores are Predictive of Achieving the Minimal
Clinically Important Difference After Treatment of Focal Cartilage Defects of
the Knee with Osteochondral Grafts Wang Dean MDChang Brenda MS, MPHCoxe Francesca R. Pais Mollyann D. BSWickiewicz Thomas L. MDWarren Russell F. MDRodeo Scott A. MDWilliams Riley J. MDHospital for Special Surgery, New York, NY, USA27 7 2018 7 2018 6 7 suppl4 2018 AOSSM Annual Meeting Abstracts2325967118S00137© The Author(s) 20182018SAGE PublicationsThis open-access article is published and distributed under the
Creative Commons Attribution - NonCommercial - No Derivatives License
(http://creativecommons.org/licenses/by-nc-nd/4.0/), which
permits the noncommercial use, distribution, and reproduction of the article
in any medium, provided the original author and source are credited. You may
not alter, transform, or build upon this article without the permission of
the Author(s). For article reuse guidelines, please visit SAGE’s website at
http://www.sagepub.com/journals-permissions.Objectives:
Osteochondral autograft transfer (OAT) and fresh osteochondral allograft
transplantation (OCA) are popular cartilage restoration techniques that
involve the single-stage implantation of viable, mature hyaline cartilage
into focal chondral defects of the knee. Both techniques have demonstrated
good results, as defined by statistically significant post-surgical
improvements in patient-reported outcome measures. Recently, there has been
greater focus on what represents a clinically relevant change in outcomes
reporting, and commonly applied metrics for measuring clinical significance,
such as the minimal clinically important difference (MCID) and substantial
clinical benefit (SCB), have become the standard. Although a previous study
defined a MCID in patients treated for articular cartilage defects in the
knee (Greco et al, AJSM 2010), these patients were treated with various
cartilage restoration procedures (e.g., debridement, microfracture,
autologous chondrocyte implantation), and none were treated with OAT/OCA.
Therefore, the purpose of this study was to define the MCID and SCB
thresholds after OAT/OCA for the International Knee Documentation Committee
subjective knee form (IKDC) and Knee Outcome Survey-Activities of Daily
Living Scale (KOS-ADL) and to determine clinical and demographic patient
factors predictive for achieving the MCID and SCB after OAT/OCA.

Methods:
A prospective institutional cartilage registry was reviewed to identify
patients who underwent OAT/OCA. The IKDC and KOS-ADL were administered
preoperatively and at a minimum of 2 years postoperatively. The MCID and SCB
of these outcome scores were calculated using anchor-based methods. Receiver
operative characteristic (ROC) analysis was used to determine the SCB using
an anchor question, with the area under the curve (AUC) used to evaluate
predictive ability. Multivariate analysis was performed to identify patient
factors associated with achieving the MCID and SCB.

Results:
In total, 173 knees in 173 patients (mean age, 33.0 ± 13.2 years; 37.0%
female) were identified. Patient demographics and clinical variables are
listed in Table 1. Using the anchor-based method, the MCID for the IKDC and
KOS-ADL were 17 ± 3.9 and 10 ± 3.7, respectively. Using the ROC method, the
SCB for the IKDC and KOS-ADL were 32 (AUC 0.86) and 10 (AUC 0.76),
respectively. Univariate analysis demonstrated no association between
procedure (OAT or OCA) or lesion location and likelihood of achieving the
MCID/SCB. In multivariate analysis, lower preoperative IKDC scores and
higher preoperative Marx Activity Scale scores were predictive of achieving
an MCID and SCB on the IKDC, and lower preoperative KOS-ADL scores, lower
preoperative SF-36 pain subscale scores, and a history of 1 or less previous
ipsilateral knee surgeries were predictive of achieving a MCID and SCB on
the KOS-ADL (Table 2).

Conclusion:
In patients treated for focal cartilage defects of the knee with
osteochondral grafts, these values can be used to define a clinically
important change and substantial clinical benefit for future outcome
studies. In this study population, higher preoperative activity levels and a
history of 1 or less previous ipsilateral knee surgeries were predictive of
achieving a clinically important change and substantial clinical benefit
after OAT/OCA. These findings have implications for managing preoperative
expectations of OAT/OCA surgery.

Table 1. Patient Demographics and Clinical Variables of Included Patients (N =
173)

Age, y	33 ± 13.2	
 Mean ± SD	56 (32.4)	
 Age <40 y	64 (37.0)	
Female sex	25.8 ± 4.5	
Body mass index, kg/m2
	1.3 ± 1.5	
No. of previous surgeries	
Chondral lesion characteristics	
 Lesion location	
 Medial femoral condyle	79 (45.7)	
 Lateral femoral condyle	59 (34.1)	
 Trochlea	28 (16.2)	
 Patella	30 (17.3)	
 Lesion area, cm2
	4.3 ± 2.6	
Procedure	
 Osteochondral autograft transfer	75 (43.4)	
 Osteochondral allograft transplantation	98 (56.7)	
Concomitant procedures	
 ACLR	2 (1.2)	
 Meniscus allograft transplantation	7 (4.0)	
 Realignment osteotomy	17 (9.8)	
Data are reported as n (%) unless otherwise indicated. ACLR =
anterior cruciate ligament reconstruction

Table 2. Multivariable Logistic Models for Achieving MCID and SCB

	Odds Ratio (95% CI)	P Value	
Achieving MCID on IKDC	
 Age (≥40 y/<40 y)	1.01 (0.43-2.40)	0.985	
 Sex (Female/Male)	0.96 (0.43-2.18)	0.923	
 Preoperative IKDC	0.95 (0.92-0.98)	0.001	
 Preoperative Marx Activity Scale	1.11 (1.03-1.19)	0.005	
Achieving SCB ON IKDC	
 Age (≥40 y/<40 y)	0.60 (0.24-1.40)	0.244	
 Sex (Female/Male)	0.69 (0.31-1.50)	0.360	
 Preoperative IKDC	0.95 (0.92-0.98)	0.001	
 Preoperative Marx Activity Scale	1.14 (1.07-1.23)	<0.001	
Achieving MCID and SCB on KOS-ADL	
 Age (≥40 y/<40 y)	0.92 (0.40-2.12)	0.845	
 Sex (Female/Male)	1.46 (0.67-3.24)	0.343	
 Previous Knee Surgeries (>1/≤1)	0.32 (0.14-0.69)	0.005	
 Preoperative KOS-ADL	0.96 (0.93-0.99)	0.009	
 Preoperative SF-36 Pain Subscale	0.98 (0.96-1.00)	0.043	
IKDC = International Knee Documentation Committee Subject Form;
KOS-ADL = Knee Outcome Survey - Activities of Daily Living
Scale; MCID = minimal clinically significant difference; SCB =
substantial clinical benefit

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