CC Sabathia, on the DL with what had been diagnosed as inflammation in his right knee, now has a real diagnosis and it is degenerative changes to the articular cartilage. Media reports did not disclose the degree of wearing of the cartilage, a factor that is crucial to understanding the pitcher’s condition.
Sabathia was reportedly slated to receive a cortisone injection and treatment with stem cells. Cortisone is simply a steroidal anti-inflammatory that may reduce the signs and symptoms but has no curative benefit for the cartilage itself. Though worth a try, there is no guarantee that the stem cell procedure will be successful.
A last resort surgical option, should the
current plan not succeed, is micro-fracture surgery, though this also offers no certain outcome.
Let’s backtrack a moment though…
You may recall from my previous post, that articular cartilage provides a smooth glassy surfacing at the ends of many bones. It facilitates movement while also protecting the integrity of the bones.
Though injuries to the articular cartilage – also known as chondral defects – often occur due to direct trauma that entails a rotational component, they may also result from degenerative changes. However, there are often factors that are predictive of the wear and tear that ultimately occurs.
Initial insults to the cartilage from prior injury – such as that causing the meniscal damage Sabathia suffered in 2010 – might have played a role in predisposing his cartilage to break down. The presence of any instability of the knee joint (such as that due to ligament sprains or tears), especially coupled with overuse also predisposes to the onset of degenerative changes, as does removal of a meniscus.
The degree of damage to articular cartilage is classified from zero, being normal cartilage, to Grade 4, which is when the surface is totally worn away exposing the bone below. Grade 4 lesions are often described as being “full thickness” resulting in a joint being “bone on bone”.
Injury to the articular cartilage most often occurs in weight-bearing sections of the bone and on the medial (inner) aspect of the knee. Restoring articular cartilage is a tough order. Due to its poor blood supply – much like the menisci in the knee – it does not heal in the way most of our other tissues generally do. Micro-fracture surgery attempts to remedy this by perforating subchondral bone in regions that are cartilage deficient
in order to stimulate a sustained reparative response by bringing blood to the region.
As for rehab, maximizing strength in the muscles crossing the hip and knee is crucial when addressing any knee issue. Strong muscles help to take some of the stress off the affected joints. Regardless of the specific treatment he receives, Sabathia will continue to work to optimize his strength.
It should be noted that as a lefty, Sabathia puts a lot of weight, force and torque on his right knee when pitching. Studies have shown that extending the lead knee “may provide stabilization allowing better energy transfer from the trunk to the throwing arm, and could be a critical factor in pitch velocity.”
I would expect CC to be out of action for longer than the 15 days dictated by his being on the DL. If not, he’ll certainly not yet be at 100% and his velocity will likely be an issue.
Follow Abby on Twitter @abcsims.
CC Sabathia, now on the DL due to an accumulation of fluid in his right knee, is reportedly likely to undergo another MRI after having the knee drained on Monday. The diagnosis – at least the one reported in the media – was inflammation, which isn’t much of a diagnosis at all. It’s what caused the inflammation that is of
the utmost concern. Though it could have simply been overuse, it is important to investigate further in order to treat properly and work to prevent future episodes.
Sabathia’s initial MRI, which was negative for meniscal involvement, may not have been as definitive as desired due to his condition at the time. The lefty, who had surgery in 2010 to repair a meniscus in the knee, commented that this time around he first noted the swelling when pitching on May 4th.
Some fluid is normal
Every knee contains some fluid – called synovial fluid – which helps to lubricate the joint to minimize friction and facilitate movement. This fluid is contained within the joint capsule, which surrounds all synovial joints. The capsule, which is lined with a membrane known as the synovial membrane, also serves to supplement the ligaments (which connect one bone to another) to provide joint stability.
Effusion versus Edema
A build-up of fluid within the joint capsule – like Sabathia’s – is called an effusion. This is distinguished from edema, which is when fluid accumulates in the soft tissues outside the joint capsule.
A knee with an effusion feels like it contains a water balloon. In contrast, edema feels like it stretches the skin and is often accompanied by redness. Both may cause the area to feel warm to the touch.
Possible causes of edema include trauma from a contusion (bruise), soft tissue injury such as muscle strains, or inflammation of a bursa.
The implications of knee joint effusion: bloody versus non-bloody
Any number of pathologies can result in fluid buildup. Some of these may be from sudden trauma, while others may be due to more chronic conditions. Trauma to the knee that causes fracture or tearing of ligaments – such as the ACL or PCL – can cause that fluid to be bloody. Damage to the highly vascularized synovial membrane can also result in hemorrhage into the joint.
If the synovium becomes inflamed, causing pain and swelling, it too can cause joint effusion. This is known as synovitis and can result from overuse.
There are two types of cartilage in the knee (view image). The medial (innermost) meniscus and lateral (outermost) meniscus are composed of fibrocartilage and serve to create a better fit for the femur and tibia at the knee and act as shock absorbers. The other – articular cartilage – provides a smooth glassy surfacing at the ends of many bones. It facilitates movement while also protecting the integrity of the bones. Both meniscal and chondral (articular cartilage) injuries can result in a localized collection of fluid. However, because both types of cartilage lack a significant blood supply, isolated injuries to these structures are not likely to result in bloody fluid.
Though meniscal and chondral injures can be caused by trauma – particularly when it involves twisting motions – both are also often caused by degenerative wear and tear. A gradual onset of symptoms, including a proliferation of fluid, might result from the latter.
Osteoarthritis, which among other things entails a wearing of the chondral surface, is a common cause of inflammation and results in various degrees of deformation of the knee.
Rheumatoid arthritis, another condition that can affect the knee, also results in pain and swelling.
At the knee, injuries often occur to several structures simultaneously. Additionally, the presence of one or more pathologies may also predispose to the onset of others (more on this as it relates to ligaments here).
Lastly, other non-traumatic causes of fluid within the knee might be localized infection or gout.
Here’s hoping Sabathia returns to form quickly.
Follow Abby Sims on Twitter @abcsims.
The healing process entails a remodeling of injured tissues, and things don’t always go as planned. Though tissues adapt well to normal stresses, chronic overuse results in maladaptation that includes an increase in scar tissue. This has a number of implications, but the end result is weakening of the tissue – be it tendon or muscle – and an inability for it to function optimally. Inadequate rest after an injury, an overly aggressive rehab program and/or premature return to activity sets the stage for this maladaptation.
A ligament generally remains lengthened after a significant Grade 2 sprain, and therefore no longer stabilizes a joint to the same degree it did before. Sufferers work to overcome injury by maximizing dynamic stability, muscle strength, and proprioception (see below), however re-injury in competitive athletics is common. Playing on an insufficiently healed
sprain will place undue stresses on the damaged tissue as well as on other stabilizing structures, inviting further damage (see RG III).
After injury, there is also a loss of proprioception, or the body’s position sense. Impaired balance is another issue, not only after lower body injuries but after upper body injury as well. Re-training balance and proprioception is included in rehab and – like strength, range of motion and flexibility – it takes time until they are at full capacity. Functional testing to determine a sufficient degree of recovery in all areas should be what dictates a return to competition.
Articular cartilage is the cartilage that lines and cushions the ends of bones, providing smooth gliding surfaces at the joints. It is known to be resistant to compression but with less than ideal tensile strength. Articular, or hyaline cartilage lacks vascularity (blood vessels), nerves and a lymphatic supply. It derives nourishment from the soft tissue that lies between the joint capsule and the joint cavity (the synovium). When overloaded, articular cartilage becomes irreparably damaged; it does not regenerate. Permanent and disabling defects can result from a premature return to sports.
The scenario might go like this: an athlete suffers a ligament sprain that results in a loss of joint position sense (proprioception). This deficit leads to altered mechanics, which would in turn place an excessive load on articular cartilage, resulting in an acute inflammation and lesions in the tissue. Wear and tear of the smooth hyaline cartilage is cumulative and, over time, the athlete’s joint may end up losing this surfacing entirely, resulting in what is known as being “bone on bone”.
The dreaded microfracture surgery – from which not all athletes emerge victorious – is one procedure often performed in an attempt to treat articular cartilage lesions. Holes are drilled through any remaining cartilage into the bone below in an effort to create a bleed. The intention is for blood and fat droplets to migrate into the defect, form a clot, and heal into a form of cartilage that will help protect the area. Rehab after microfracture initially requires a significant protective non-weightbearing phase and, even after a lengthy and cautious program, successful return to high-impact sports may not be possible (see Greg Oden).
Fibrocartilage, present in only several joints, is most recognized for its role at the knee. Known as the menisci, these structures act as the shock absorbers at the joint, also creating a better fit for the femur and tibia. Lacking a substantial blood supply, particularly in the central regions, significant injuries to the menisci (tears) may require surgery. Because of the lack of nourishment from blood, meniscal surgery is more often performed to remove a torn segment rather than to repair the damage. Return to sports too soon after arthroscopic surgery is likely to result in impaired performance. Of even greater significance, is that it may increase the likelihood of arthritic changes down the line.
Bone contusions, and even more so fractures, may seem to be scariest to an athlete. In fact, in most cases, because bone healing generally occurs in a four to six week window, a simple fracture mends in a more straightforward fashion than soft tissue. Contusions also generally resolve by the six to eight week mark. In contrast, displaced fractures – where the ends of the broken bone are out of alignment – require surgery (typically an internal fixation with plates, rods and pins) in order to heal properly. Fractures may be accompanied by soft tissue injury as well. The time required for athletes to return to sports after fracture is obviously greater than the healing time of the bone, as it also entails restoring any joint mobility lost due to immobilization, as well as achieving all the parameters of healing and function required after other musculoskeletal injuries.
When reporters inform us how long an athlete is expected to be out of action from an injury, they are reporting what they’ve been told. No one should base a fantasy team or bet the under on these predictions. In contrast with how most of us have learned to set a low-end realistic bar on expectations in order to exceed them, pro teams generally set our expectations of their athletes’ recovery too high, positioning them for failure. I’ve no idea why.
Follow Abby Sims on Twitter @abcsims.
*Note: My thanks to Michael T. O’Donnell, PT, DPT and Stephen Reischl, PT, DPT, OCS for an excellent presentation on Musculoskeletal Tissue Healing at the APTA conference last week. I’ve taken the liberty of boiling down much of the information (while adding my own two cents) in the writing of this article.