MENISCUS

Meniscectomy

Tips to successful meniscal surgery

1. Every knee operation should start with an examination under anaesthesia
2. Set up for arthroscopy is important to avoid intraoperative difficulties
3. Adequate visualisation of the whole meniscus up to the peripheral rim
4. Always probe the meniscus including superior and under surface of the posterior horn
5. Get the antero-medial portal right by using a needle to triangulate the compartment that needs maximal attention. The portal has to be just suprameniscal and not too high.
6. Swapping the camera into the antero-medial portal can be extremely useful for operating on the anterior half of medial meniscus and posterior horn of lateral meniscus
7. Arthroscopic shavers are especially useful for degenerate meniscal tears
8. Leave a stable peripheral rim
9. Avoid sudden change in contours

Techniques

Posterior horn tear

1. The use of a leg holder can facilitate better visualisation of the posterior horn and visualising the posterior rim width for longitudinal tears is essential to increase meniscal repair rates.
2. Adjusting the degree of knee flexion (0-20 degrees) and avoiding internal rotation of the tibia is more important than just purely valgus force.
3. Dropping the height of the table can also help.
4. Getting the antero-medial portal right is critical
5. Low profile arthroscopic meniscectomy punches are useful in tight knees
6. View through the notch for dealing with remnant flaps of the posterior horn
7. The 4.5 mm synovator blades are only 1/3 uncovered and are less likely to produce scuffing of the femoral condyle

 

Radial Tear

1. Radial tears are common in the lateral meniscus and posterior horn medial meniscus. Basketball players have a higher chance of getting radial tears.
2. Look for a truncated triangle or cleft for diagnosing radial tears on MRI scans
3. Radial tears extending up to the meniscal rim in young patients should be repaired
4. Avoid sudden change in contour when trimming radial tears and confirm this by swapping portals and visualising

radial tear	partial meniscectomy of radial tear

Flap tear

1. These tears can be missed if the meniscus is not carefully probed
2. Quite often they form part of a complex tear with cleavage involving the posterior horn and with degenerate knees
3. Use of arthroscopic scissor punches by resection at the base of the flap can quicken the procedure

Bucket Handle tear

1. Reduce the bucket handle tear first using a probe
2. In chronic bucket handle tears reduction can be difficult and sometimes a small grasper can help reduction
3. Check the volume of meniscus that may have to be removed and consider repair even in some white-white tears based on the clinical situation
4. For resection, the two standard portals are generally sufficient but some surgeons may prefer to use a separate grasping portal
5. Using a scissor punch, resect the posterior attachment of the bucket handle leaving a few strands
6. Then swap portals if the bucket handle tear extends quite anteriorly
7. Then the posterior resection can be completed and the meniscal fragment grasped and removed
8. Avoid leaving a residual flap at either end, and if present address them using a shaver or punch.

 

 

 

 

 

Horizontal cleavage tear

 

1. These are often degenerate tears and can be associated with a meniscal cyst

 

2. Leaving one of the leaves of the meniscus can reduce joint contact pressures but if the leaves are degenerate and involving the whole meniscus then there is risk of potential re-tear
3. Leave a stable rim
4. A spinal needle or probe can be passed through the horizontal cleavage to decompress the cyst.
5. A shaver can be used to create a channel between the joint and the cyst through the horizontal cleavage
6. The cyst could be manipulated to empty its thick jelly-like contents into the joint (see picture)

Degenerative tear

Results

The recovery from arthroscopic partial meniscectomy usually takes only a few weeks. Factors like age, period from injury to surgery and BMI do not affect short-term recovery. Patients can have a home-based rehabilitation programme and return to sports can be as short as 2-3 weeks.

There is greater than 90% long-term satisfactory outcomes with partial meniscectomy at 10-15 years follow-ups. The need for revision for surgery is usually due to inadequate surgery, leaving abnormal meniscal contour or due to coexisting chondral changes in the knee. Age does not affect outcome

Risk factors for long-term worse outcomes and osteoarthritis

Numerous long-term studies of partial meniscectomy suggest that there is radiological joint space narrowing in 22-48% of patients. With subtotal meniscectomy this can be 80-100%. The factors that consistently affect progression of osteoarthritis and overall functional outcomes are

1. Greater size of meniscal resection
2. Female sex
3. Articular cartilage degeneration assessed at surgery
4. Prior surgery on the index knee
5. Body mass index >30
6. Degenerate tears had poorer outcomes and flap tears had a higher reoperation rate

Complications

Overall complication rate is 1.68% as reported by Small (1990)

1. Infection- The infection risk is about 0.1% and there is has been no benefit reported in using prophylactic antibiotics for routine arthroscopy.
2. Haemarthrosis- commonest complication reported
3. Nerve injury- The risk is about 0.01% and is more likely after meniscal repair
4. Failure- due to inadequate resection or due to chondral changes
5. Thrombosis- less than 0.1%
6. Painful portals
7. Reflex sympathetic dystrophy
8. Osteoarthritis

Discoid Meniscus

The discoid meniscus is an anatomical variation of the meniscus, involving the lateral meniscus in upto 5% of the population and occasionally affecting the medial meniscus. It appears to be more common in Japanese and Koreans. Symptoms occur due to meniscal tear or due to snapping as a result of unstable rim.

Watanabe (1992) described three types-

• Complete,
• incomplete (which still retains semilunar shape) and
• Wrisberg type (unstable posterior horn).

Peripheral rim instability is present in 28-77% of discoid menisci. In the past, Wrisberg type unstable menisci were treated with complete meniscectomy. Newer studies report good long-term outcomes with repair of the meniscus to the capsule. Meniscal tears are treated by partial meniscectomy and saucerisation and if there is an unstable meniscus, by repair to the capsule.

References

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Rosenberg TD, Metcalf RW, Gurley WD. Arthroscopic meniscectomy.
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Bin SI, Kim JM, Shin SJ. Radial tears of the posterior horn of the medial meniscus.
Arthroscopy. 2004 Apr;20(4):373-8. Review.

Haemer JM, Wang MJ, Carter DR, Giori NJ. Benefit of single-leaf resection for horizontal meniscus tear. Clin Orthop Relat Res. 2007 Apr;457:194-202

Grana WA, Szivek JA, Schnepp AB, Ramos R. A comparison of the effects of radiofrequency treatment and mechanical shaving for meniscectomy. Arthroscopy. 2006 Aug;22(8):884-8

Howe TS, Koh JS. Arthroscopic internal marsupialization of meniscal cysts.
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Spahn G. Arthroscopic revisions in failed meniscal surgery. Int Orthop. 2003;27(6):378-81.

Burks RT, Metcalf MH, Metcalf RW. Fifteen-year follow-up of arthroscopic partial meniscectomy. Arthroscopy. 1997 Dec;13(6):673-9.

Fabricant PD, Jokl P.Surgical outcomes after arthroscopic partial meniscectomy.
J Am Acad Orthop Surg. 2007 Nov;15(11):647-53. Review.

Rockborn P, Messner K. Long-term results of meniscus repair and meniscectomy: a 13-year functional and radiographic follow-up study. Knee Surg Sports Traumatol Arthrosc. 2000;8(1):2-10

Pearse EO, Craig DM. Partial meniscectomy in the presence of severe osteoarthritis does not hasten the symptomatic progression of osteoarthritis. Arthroscopy. 2003 Nov;19(9):963-8. Review

Shelbourne KD, Carr DR. Meniscal repair compared with meniscectomy for bucket-handle medial meniscal tears in anterior cruciate ligament-reconstructed knees.
Am J Sports Med. 2003 Sep-Oct;31(5):718-23.

Scheller G, Sobau C, Bülow JU. Arthroscopic partial lateral meniscectomy in an otherwise normal knee: Clinical, functional, and radiographic results of a long-term follow-up study. Arthroscopy. 2001 Nov-Dec;17(9):946-52

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