Articular Cartilage Pathology: What to do?

A syringe delivering PRP:
A silver bullet for osteoarthritis?

My fall was so busy, I’m finally getting back to doing a sequel of a post I wrote in early October:  Osteoarthritis Part I.

I’m finally writing “Part II.”

The proximal impetus for finally attending to this item on my personal ‘to do’ list?  The new, January 2014 edition of the Clinical Journal of Sports Medicine has a couple of very fine articles on the treatment of articular cartilage pathology. One of the studies, “Treatment of Cartilage Defects of the Knee: Expanding on the Existing Algorithm,” is a general review I hope to post about in the near future.  The study that is in my line of fire today explores the uses of platelet-rich plasma (PRP) in the treatment of osteoarthritis and cartilage defects: “Platelet-rich Plasma in the Management of Articular Cartilage Pathology:  A Systematic Review.”

I found this review to be incredibly helpful.  It begins with an overview of articular cartilage pathology and a reminder of the frustrations in treating a tissue that has a limited inherent healing capacity.   Rarely can articular cartilage repair itself.  And when injury penetrates subchondral bone, underlying marrow cells can be stimulated to provide some repair, but inevitably the fibrocartilage that results is a biomechanically inferior substitute for native, articular hyaline cartilage.

OCD of the medial femoral condyle:
what will this joint look like in 2044?

The review notes the increasing incidence of chondral and osteochondral lesions, something as a pediatric sports medicine specialist I can attest to.  The 10 year old with knee OCD I am treating today:  I often wonder what their knee will be like in 30 years?

The authors note:   “Several treatment modalities are available, including microfracture, autologous chondrocyte transplatation, and autograft and allograft osteochondral transplantation.  However, the reported resulst with these procedures have been variable and are not guaranteed to prevent symptomatic degenerative disease at long-term follow up.”

In other words, the hunt is on for an effective, definitive treatment of articular cartilage injury.  Might PRP be the answer?

The brief answer:  we need to learn much, much more about PRP, and probably about articular cartilage, too.

Let’s start with the limitations.  First, the investigation of PRP for these uses is very, very new.  The authors of the review note that only one of the studies that met their inclusion criteria (N = 10) was published before 2012.  Of the ten studies in their review,  the majority dealt with joints in which osteoarthritis (OA)  was already present, when the proverbial horse is already out of the barn so to speak.

Only two of the studies were randomized controlled trials.  Most of the studies reviewed have very short-term follow up.  The authors note that in excluding studies published in languages other than English they may be missing relevant results.  They note an inherent publication bias that exists in the field that skews toward publishing studies that report favorable results of interventions.  They underscore the inability to generalize from most of the studies, as there is great heterogeneity of how PRP is prepared and delivered.

Finally, there was also broad variability among the design of the studies included.  Some involved looking at PRP injections while two looked at PRP as an adjunct to surgical drilling of focal chondral defects.

I was particularly interested in the section of the paper that reviewed the various outcome measures that have been employed in assessing the clinical outcomes of the various studies included in the systematic review.  Patient-reported outcome measures are a special interest of mine.  The Western Ontario and McMaster Universities’ Arthritis Index (WOMAC) was the most commonly reported clinical score, whaile a visual analogue scale (VAS) was the most commonly used pain scale.  Some studies looked at overall health-related quality of life (HRQoL) and used measures such as the SF-36.  The Harris Hip score was used in one of the studies looking at ultrasound guided injections of PRP into the hip for OA of that joint.

The authors conclude that the majority of studies in the literature look at OA of the knee and that the measured clinical outcomes (functional disability and pain) lessen after 6 months; there is a dearth of high-quality evidence to support the use of PRP ofr chondral pathology; and that there is a great need for high-quality randomized controlled trials “…both of PRP injections compared with placebo and surgical treatment supplemented by PRP compared with operative management alone.”

Do you use PRP in your practice?  If so, do you use it to treat chondral defects or OA?  If so, we would love to hear your comments or on twitter @cjsmonline.  Make sure you visit the web page as well to check out the study itself.