Chondromalacia patella, Softening and degenerative
changes in the posterior surface of the patella.
Plain radiography of the knee is of limited use, on a skyline
axial projection the small fissures may be visible and in the final
grade 4 stages osteoarthritic-sclerotic changes take place and
osteophytes are visible
MR is able to provide sagittal and axial reconstructions to aid early
First used by Aleman in 1917, chondromalacia patella was the name
given to a degeneration of the patellar articular cartilage (Kipnis
and Scuderi, 1995). True chondromalacia patella involves the
degeneration of the articular facets of the patella, with resulting
ragged fronded edges, (Welsh and Hutton, 1990), and is a very common
injury amongst both men and women of our sporting population
Along with osteoarthritis, chondromalacia patella is a type of
cartilage damage resulting in anterior knee pain. It is also named
as a cause of the symptoms of patellofemoral pain syndrome (Reid,
1992). When compared to the number of patients who are seen with
patellofemoral pain, and those with actual changes to the articular
cartilage of the patella, chondromalacia patella is a rare condition
though (Nofthall, 1990).
Cartilage changes occur due to excess compression which disrupts the
intermediate and deep layers of cartilage of the patella’s articular
surface (Reid, 1992). Kulund, 1988, also describes changes which
occur to the subchondral bone – microfractures and sclerosis – both
of which make the bone less resilient and lead to greater shock to
the cartilage. Most chondromalacic changes are seen along the median
ridge of the patella, and here cartilage is thickest (Kulund, 1988).
Chondromalacia patella begins with oedema of the cartilage and this
cartilage is very easily damaged. Microscopically there are small
fissures in the cartilage and the chondrocytes appear normal. (Vigorita
and Morgan, 1995). Reid, 1992, also notes the cartilage will feel
spongy when probed and describes this as the classic blister lesion.
Outerbridge, in Vigorita and Morgan, 1995, describes grade II
fissures in the cartilage as being no greater than 1.3cm in area,
while Reid, 1992, adds that the fissures do not extend into
subchondral bone at this stage.
Fissuring and fragmentation and fibrillation, which extends to the
subchondral bone can now be seen, but this degeneration covers less
than 50% of the patella (Reid, 1992). Vigorita and Morgan, 1995,
note that chondrocytes also become effected in this stage of
degradation and they not only become hyperactive but also
degenerate. This is necrosis of the cartilage and some chondrocytes
may even become fibrous (Vigorita and Morgan, 1995).
Both Reid, 1992 and Vigorita and Morgan, 1995, note the now
chondromalacic changes extend into bone and involve more than half
of the patella surface. Now osteoarthritic-sclerotic changes take
place and osteophytes are formed (Vigorita and Morgan, 1995).
Most important the patient must begin to avoid activity that has
caused the problem, which means for most athletes with
chondromalacia patella, training has to be limited to cycling or
swimming, activities that do not lead to chondromalacia patella
(Welsh and Hutton, 1990).
Reid, 1992, describes arthroscopy as a diagnostic tool that can be
used to not only assess the degree of articular degeneration, but
during which, procedures can be carried out.
First treatment usually includes intra-articular debridement, and
should also be combined with lateral retinacular release (Welsh and
Hutton, 1990). (See figure 8). Cushner and Scott, 1995, note that a
lateral retinacular release is important if the lateral retinaculum
is tight, as this can laterally displace the patella during knee
flexion. Contraindications for lateral release are: