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IN A NUTSHELL

Assessment of Quality and The images obtained during X-ray exams may be viewed on

Viability of Cartilage Tissue
film or put through a process called “digitizing” so that they
can be viewed on a computer screen.

Fluoroscopy is an imaging technique that uses X-rays

to obtain real time moving images. In its simplest form a
fluoroscope consist of an X-ray source and the fluorescent

Cecilia Pascual-Garrido, MD
screen between which the patient is placed. There are two
main configurations of permanently installed fluoroscopic
University of Colorado, Denver, CO, USA
systems. One class commonly utilizes a radiolucent patient

examination table with an under-table mounted tube and
an imaging system mounted over the table, while the other

is commonly referred to as a C-arm system used where
greater flexibility in the examination process is needed

such as in orthopedic procedures. Currently, fluoroscopy is
Intra-operative assessment of cartilage quality and viability the main imaging modality in orthopaedic surgery despite
is crucial to decide the best surgical treatment option.
advancements in navigation surgery. It is crucial that both
Reparative procedures such as: drilling, ORIF etc attempt the orthopedic surgeon and radiology technologyst are
to restore the native articular cartilage. On the contrast,
restorative treatments (microfracture, allograft, OATS, ACI, De familiar with it use. Recently a study performed by Pally et al.
revealed that there is lack of standard technology employed
Novo etc) attempt to replace damaged cartilage with hyaline by surgeons and techs with regards to direction of the
or hyaline type tissue. Deciding on performing reparative or
fluoroscopy. This lead to delays, more radiation exposure and
restorative treatment will depend on multiple factors including frustration. A potential system to facilitate communication
quality and viability of the tissue.
between surgeon and tech should be developed to increase
Macroscopically, hyaline cartilage is normally characterized efficiency.

with a pearly bluish in color with firm consistency. On the
contrast, fibrocartilage must be suspected when a white What is RF plasma?
RF stands for radiofrequency. It means “controlled ablation”
fibrous color is observed. Presence of cracks, fissures,
defects, blisters are also important to assess cartilage and refers to the process of surgically dissociating tissue
using plasma-based radiofrequency device. This technology
damage. Definitive diagnosis of hyaline or fibrocartilage tissue
is performed histologically. Safranin O is the most common has applications across several surgical fields. The primary
stain used to assess cartilage tissue. The intensity of Safranin operating method for this technology are: tissue ablation

O is directly proportional to the proteoglycan content.
(tissue removal), tissue coagulation (shrinkage) and hemostasis.

Macroscopically, cartilage viability is not possible to assess. The RF could be used in two settings: non plasma and plasma
Optical coherence tomography (OCT) has been developed settings. The difference among them is the amount of voltage

to assess cross-sectional images of articular cartilage that is apply. At lower settings, the heated fluid interacts with
arthroscopically in near real time at resolution (10-20um) that nearby tissue which produces the tissue to shrink. At higher
settings, the electrical field interacts with surrounding fluid,
are comparable to low power histology. Clinical data have
shown that OCT can be used clinically to provide qualitative such as saline, to excite electrolytes and molecules in the
solution and create a high-density energy field called plasma.
and quantitative assessments of early articular cartilage
degeneration strongly correlating with arthroscopy.
What is the difference between Bipolar & unipolar
Histologically, the 2 most common reagents to assess Diathermia?

viability are calcein-AM and ethidium homodimer (EtHd). The Diathermia is the use of high frequency to produce heat. The
combination of calcein–AM and EtHd is commercially sold effects of diathermy depend on the current intensity and
as a staining kit (Live-Dead assay). Live cells emit a green
wave–form used. Coagulation is produced by interrupted
fluorescence while dead cells emit a red stain. Recently pulses of current. Cutting is produced by continues current.
the specificity of this staining system has been questioned,
Monopolar uses an electrical plate that is placed on patient
specially when cartilage is stored at 4C for fresh cartilage
allograft. More specific, consistent and accurate means of and acts as indifferent electrode. The current passes between
the instrument and the indifferent electrode. Localized heating
analyzing viability is still necessary.
is produced at the tip of instrument. Bipolar consist of a
What’s the difference between X-ray and fluoroscopy
forceps (instrument). The two electrodes are combined in the

An X-ray machine produces a controlled beam of radiation, forceps. Current passes between tips and not through the
which is used to create an image of the inside body. This patient.

beam is directed at the area being examined. After passing
through the body, the beam falls on a piece of film or a special

plate where it casts a type of shadow. Different tissues in the
body block or absorb the radiation differently.

36 ISAKOS NEWSLETTER 2014: Volume II