Arthroscopic partial medial meniscectomy stands the test of time

Age, gender and meniscal tear types had no major effect on the long-term results, researcher says.

Arthroscopic partial medical meniscectomy showed strong long-term results and high patient satisfaction in a retrospective study. The procedure may benefit sports medicine because of the number of study patients who resumed full athletic activity after surgery.

Patients underwent clinical, functional and radiographic assessments at an average 18.5 years postop. Most operated knees showed positive results, with 36% excellent, 47% good and only 17% poor, Robin Michael Gehrmann, MD, of Newark, NJ, said at the American Academy of Orthopaedic Surgeons 73rd Annual Meeting in Chicago.

According to Gehrmann, damaged articular knee cartilage influenced outcomes, but patient age and gender, and types of meniscal tears did not significantly affect results.

Patient selection

Surgeons performed 256 arthroscopic partial medial meniscectomies between January 1985 and December 1988. All operations involved the posterior one-third of the meniscus and a stable peripheral rim, Gehrmann said.

The study included 72 knees among 60 men and 12 women with a mean age of 47.5 years. Seventy-two percent of patients participated in recreational sports, Gehrmann noted.

Researchers split the patients into two groups. The first group included 56 knees (78%) that had Outerbridge Grade I or Grade II chondral damage. The second group included 16 knees (22%) with Outerbridge Grade III or Grade IV chondral damage.

Function was measured using the Lysholm and Tegner scales, and Outerbridge scores were used to gauge cartilage changes. The researchers also took standing anteroposterior weight-bearing radiographs of both knees. Nonoperated and uninjured knees served as internal controls, Gehrmann said.

Improved function

The researchers rated patients’ overall results as excellent, good or poor. They defined an “excellent” result as a Lysholm score greater than 95, less than 2 mm of compartment narrowing and no side-to-side radiographic grade difference.

A “good” result was defined as a Lysholm score of 85 to 94, compartment narrowing of 3 mm to 5 mm and a maximum side-to-side radiographic grade change of one. And a “poor” result was defined as a Lysholm score of less than 85, compartment narrowing of more than 5 mm and a grade change higher than one, according to the study.

At an average follow-up of 18.5 years, the researchers found that mean Lysholm scores improved to 91 from 42 preoperatively. The average Tegner score also increased, from 3.2 preoperatively to 5.3 postoperatively, Gehrmann said.

At final follow-up, 27 knees (37%) of knees had “normal” radiographs without evidence of osteoarthritis, 30 knees (42%) showed Grade I medial compartment arthritis and 15 knees (21%) showed Grade II medial compartment arthritis. No knees had evidence of Grade III or Grade IV arthritis.

Overall, there was a significant difference in radiographic grade between operated and nonoperated knees, with operated knees having a radiographic grade of 0.62 and non-operated knees having a grade of 0.34 (P=.001), according to the study.

The operated knee’s side-to-side radiographic difference was only 0.28 of a grade worse than the nonoperated knee, Gehrmann noted.

Overall, 56 knees (95%) in the first group had good or excellent results and three knees (5%) had poor results. In the second group, seven knees (44%) had good or excellent results and nine knees (56%) had poor results, according to the study.

Patient satisfaction averaged 8.1, and 32% of patients returned to sports without restrictions, Gehrmann noted.

For more information:
Patel DV, Gehrmann RM, Bibbo C, et al. Long-term results of arthroscopic partial medial meniscectomy in an otherwise normal knee. #155. Presented at the American Academy of Orthopaedic Surgeons 73rd Annual Meeting. March 22-26, 2006. Chicago.