and performance-based outcomes after knee autologous chondrocyte implantation:
A timeline for the first year of recovery.

Howard JS, Mattacola
CG, Mullineaux DR, English RA and Lattermann C. J Sport Rehabil. 2014 [Epub Ahead of Print].

Home Message: Following autologous chondrocyte implantation (ACI), performance
based and patient-reported outcomes can be valuable for measuring success. Patient-reported
outcomes were better at all post-operative time points while performance-based
measurements decreased for the first 6 months following ACI.

The success of autologous chondrocyte implantation (ACI), a common treatment for symptomatic articular cartilage defects, is
normally measured through patient-reported outcomes. Despite this,
performance-based metrics could also be used yet no one has recorded the timeline
for recovery with patient-reported or performance-based measurements. A better
understanding of the recovery timeline for both types of outcomes could help us
optimize our rehab protocols and educate our patients about their anticipated
recovery. Therefore, Howard and colleagues assessed performances-based and
patient-reported changes in knee function over 1 year after ACI. Fifty patients
participated in the study (31 male, on average 35 years of age with 1.5 treated
cartilage defects). One surgeon performed all of the ACI procedures, which
included 24 patellofemoral joints and 26 tibiofemoral joints. Some patients
also had other procedures performed on their knee (e.g., 4 high tibial
osteotomies, 2 meniscal transplantation). All patients completed a standardized
rehabilitation program. Patient-reported outcome measures assessed general
physical health (Short Form-36 PCS) and knee-specific
symptoms and function (WOMAC, IKDC, and Lysholm scale). Performance-based
assessments were walk-across, weight-bearing squat, sit-to-stand, step-up/over,
and lunge. All measurements took place before ACI and at 3, 6, and 12 months
post-surgery. Data for 39 patients was available at 1 year post-surgery. Compared
with prior to surgery, patient-reported outcome scores showed improvement at 3
months post-surgery and continued to improve up to 12 months post-surgery. In
contrast, performance-based measurements decreased at 3 and 6 months
post-surgery (for example, increased asymmetry of weight distribution when
squatting, longer performance times for stepping activities). The patients’
performed functional activities better at 12 months but these improvements were
often not back to previously reported norms.

ACI is becoming more common and these results should help clinicians educate
patients about what to expect after an ACI procedure. Firstly, the researchers showed
that using a combination of performance-based and patient-reported outcomes can
offer clinicians 2 different perspectives of a patient. Having both types of
measurements could be particularly helpful when the patient reports feeling
good and wants to return to play but their performance on functional tasks show
that they are not ready. Further, the researchers were able to develop a
12-month timeline for recovery following ACI. This provides clinicians with yet
another tool to assess patient progress. While this can be extremely useful to
those clinicians who oversee ACI patients, there were 2 major limitations of
this current study that should be brought to light. Firstly, the patient
population of this study was small and lacked diversity. This in turn limits
the applicability of the recommended timeline for treatment to all ACI
patients. Secondly, the current study’s follow up period was relatively short
and should seek to better understand the outcomes of the entire rehabilitation
process and not just the 1st year. While more research is completed,
the current study’s recommendations give clinicians the best overall
understanding of the ACI rehabilitation process to date. It also is a great
example of why we need to assess patient-reported and performance-based
outcomes. This can help inform our treatment strategy and help us educate the

Questions for Discussion: When you assess a patient
during a rehab program do you use patient-reported and performance-based
outcome measures? Have you found that asking a patient to perform a functional
assessment helps them realize their actual limitations or improvements?

Written by: Kyle Harris
Reviewed by: Jeffrey Driban

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Howard, J., Mattacola, C., Mullineaux, D., English, R., & Lattermann, C. (2014). Patient-Oriented and Performance-Based Outcomes After Knee Autologous Chondrocyte Implantation: A Timeline for the First Year of Recovery Journal of Sport Rehabilitation, 23 (3), 223-234 DOI: 10.1123/jsr.2013-0094