Degenerative changes in the knee
are seen with increasing frequency in patients over 40 years of age.
Arthroscopic debridement is a reasonable alternative in those patients who
have persistent symptoms despite adequate and complete conservative
measures.
Persistent pain, swelling, joint irritability, mechanical locking and
limitation of every day activities are the most common symptoms in many of
these patients. Adequate conservative treatment such as weight loss,
physical therapy, analgesics and anti-inflammatory medication controls the
symptoms in most cases. In some, however, debridement and irrigation of
the arthritic knee endoscopically is of great assistance and may reduce
the symptoms for some years. In some patients, the arthroscopic
debridement has a very substantial effect and no further treatment is
required for years. In others, the improvement is relatively minor. A
study was undertaken by one of the authors to review prospectively 276
knees with this early degenerative change treated by arthroscopic
debridement. Patients with ligamentous instability or significant
malalignment (more than 15 degrees) were excluded. Fifty patients (20%)
had previous operations on their knees, including open and arthroscopic
meniscectomies, synovectomy, removal of loose bodies and patellectomy.
Operative technique
Standard anteromedial and anterolateral arthroscopic portals should be
used and a full assessment and visualization of all areas of the knee
joint performed. The most important procedure is the excision of any
degenerative meniscal tears. The meniscus should be trimmed down to a
stable peripheral rim and the rim smoothed with powered instrumentation.
Loose bodies and debris are generally removed. Chondral flaps and
irregular chondral fractures can be smoothed down with arthroscopic
curettes and a powered meniscotome. In patients with a severe hypertrophic
synovitis, a limited synovectomy may be performed using the powered
instrumentation. In those with chondrocalcinosis, a limited synovectomy to
reduce some of this crystal laden synovium may be undertaken.
Any large, impinging osteophytes, particularly in the intercondylar region
of the femur and anterior region of the intercondylar region of the tibia
should be excised using a small osteotome and then removed with a rongeur,
taking care to avoid creating a loose body. In patients with some flexion
contracture, the removal of anterior osteophytes is extremely successful
in restoring flexion and extension of the knee, with an added substantial
improvement in comfort.
In patients with eburnated zones of tibial plateau and condylar surface, a
limited abrasion arthroplasty should be undertaken using a high speed burr
The bone surface should be perforated at multiple points.
Postoperatively, the patient should be immediately mobilized and given
physical therapy and rehabilitation to the very maximum. Immediate weight
bearing should always be encouraged.
Arthroscopic debridement and irrigation is recommended in
well-motivated, carefully selected patients with early symptomatic
osteoarthritis of the knee. The procedure is frequently successful as
stated, and if it is unsuccessful there is still recourse to corrective
osteotomy or eventual replacement arthroplasty.
Use of the laser in arthroscopic surgery
Chondral flaps, chondral fractures and tears, and chondromalacia smoothing
is undertaken easily and accurately using a laser. The Holmium YAG laser
is now considered the tool of choice in removal of the chondral layers.
The probe is used in a tangential cutting fashion and very accurate
removal of the disturbed chondral surface can be achieved, maintaining the
deeper layers of the hyaline cartilage in tact. The cutting of the
meniscus and other structures using the laser is very slow, but the
chondral surfaces are well prepared. |
