Meniscal Transplantation

synonyms:

Meniscal Transplantation CPT

Meniscal Anatomy

• Medial meniscus: C-shaped; anterior horn attaches ?; posterior horn attaches anterior to the insertion of the posterior cruciate ligament. (Johnson DL, Arthroscopy 1995;11:386) Average length = 45.7mm (McDermott ID, Knee Surg Sports Traumatol Arthrosc 2004;12:130). Secondary stabilizer to anterior tibial translation.
• Lateral Menisus: semicircular; anterior horn attaches adjacent to the ACL; posterior horn attaches behind the intracondylar eminence.(Johnson DL, Arthroscopy 1995;11:386) Average length = 35.7mm (McDermott ID, Knee Surg Sports Traumatol Arthrosc 2004;12:130).
• Discoid variant of the lateral meniscus is found in 3.5% to 5% of patients. (Vandermeer RD, Arthroscopy 1989;5:101)
• Average excursions of the menisci with knee flexion = 5.2 mm for the medial and 11 mm for the lateral meniscus. (Thompson WO, AJSM 1991;19:210)
• Medial meniscus transmits 50% of the load in the medial compartment. Lateral meniscus transmits 70% of the load in the lateral compartment. (Greis PE, JAAOS 2002;10:168)
• Blood supply: the outer 10% to 30% has blood supplied from the perimeniscal capillary plexus off the superior and inferior medial and lateral genicular arteries. (Arnoczky SP, AJSM 1982;10:90)
• see also Medvecky MJ, JAAOS 2005;13:121

Meniscal Transplantation Indications

• Symptomatic (compartmental joint line pain) meniscal deficiency which have failed non-operative management in a patient <40y/o.
• Medial meniscal deficent knee with concomittent ACL deficieny and anteromedial rotatory instability. (Sekiya JK, AJSM 2003;31:896)

Meniscal Transplantation Contraindications

• Outerbridge grade 3 or worse articular cartilage changes in the affected compartment. (unless repaired concurrenlty)
• Knee instability (unless repaired concurrenlty)
• Varus or valgus malalignment. (unless repaired concurrenlty)
• Arthritic changes (osteophytes) on Xray
• Flattening of the femoral condyle

Meniscal Transplantation Alternatives

• Nonsurgical treatment: unloading braces, activity modifications, nonimpact exercises, and NSAIDs.

Meniscal Transplantation Pre-op Planning / Considerations

• Generally use fresh-frozen allograft which must be arranged with a tissue bank. Most tissue banks use plain radiographs for allograft sizing as described by Pollard. (Pollard ME, Arthroscopy 1995;11:684). Graft should be within 5% of the native meniscus (Shaffer B, AJSM 2000;28:524).
• Pre-operative xrays including weight-bearing 45 degree flexion P/A, Merchant and lateral knee films as well as long leg alignment views should be evaluated for signs or arthritis as well as malalignment.
• Generally arthroscopy has been previously performed demonstrating meniscal deficiency and degree of arthrosis.

Meniscal Transplantation Technique

• see Sekiya JK, JAAOS 2006;14:164.

Meniscal Transplantation Complications

• Arthritis
• Failure requiring revision or menisectomy
• Graft shrinkage / displacement.
• Pain
• Stiffness, loss of motion
• Infection

Meniscal Transplantation Follow-up Care

• Hinged-knee brace with 0 to 90° of motion, 25% weight bearing with crutches for 4 wks.
• Full weight bearing and flexion beyond 90° usually is allowed after 6 to 12 weeks postoperatively.
• Squating is prohibited for 4 months.
• Patients may return to sedentary work at 1 week, strenuous work at 3 to 4 months, low-impact exercises at 8 weeks, and running after 4 to 5 months. Light or moderate sports are allowed at 6 to 9 months.

Meniscal Transplantation Outcomes

• Meniscal transplant patients generally do not return to high-level competitive activities.
• ADL score = 86+/-11; Sports Activities Scale score = 78+/-16; Lysholm score = 84+/-14. SF-36 scores indicates pts functioning at a level similar to the age- and sex-matched population. 71% greatly improved, 26% somewhat improved, 3% without change. (Yoldas EA, Knee Surg Sport Traumatol Arthrosc 2003;11:173).
• 28% of medial allografts and 16% lateral allografts fail. Mean cumulative survival time = 11.6 years. 74.2% medial ten year survival. 69.8% lateral ten year survival. Survival time is increased with concomittant high tibial osteotomy. (Verdonk PC, JBJS 2006;88A suppl 1;109).

Meniscal Transplantation Review References

• Sekiya JK, JAAOS 2006;14:164
• Cole BJ, ICL 2003;52:383
• Rodeo SA, AJSM 2001;29:246