MRI evaluation of isolated arthroscopic partial meniscectomy patients at a minimum five-year follow-up

Abstract

Background: The risk of radiographic knee degeneration after partial or total meniscectomy is well documented, but no prior study has employed cartilage-sensitive MRI technology to assess degenerative changes after meniscectomy.

Hypothesis: Arthroscopic partial meniscectomy results in early articular cartilage wear and subchondral bony degeneration, even in the absence of clinical symptoms, and these findings can be evaluated with cartilage-sensitive MRI.

Study design: Retrospective cohort.

Methods: Twenty-nine patients (ages: 15-40) who had undergone isolated arthroscopic partial medial or lateral meniscectomy with at least 5-year follow-up were evaluated. All patients had arthroscopically normal articular cartilage at the time of initial meniscectomy. Seventeen patients (18 knees) underwent partial medial meniscectomy (MM) and 12 patients underwent partial lateral meniscectomy (LM) with mean follow-up of 8.4 and 7.1 years, respectively. Follow-up evaluation included physical examination, outcome questionnaires, and cartilage-sensitive MRI examination with modified Outerbridge grading of articular surfaces.

Results: Outerbridge grades II-IV were noted in 64% of medial compartment joint surfaces in group MM knees versus 33% of lateral compartment joint surfaces in group LM knees. Abnormal cartilage surfaces (grades II-IV), subchondral sclerosis, and condylar squaring were all significantly more frequent after medial meniscectomy (p < 0.05). Groups MM and LM had no significant differences among outcome scores, which remained excellent in both groups. A significant negative correlation was found between the severity of cartilage wear and functional scoring in the MM group, suggesting that functional disability lags behind early MRI evidence of degeneration.

Conclusions: Despite optimal preoperative prognostic factors and excellent functional outcomes, MRI evidence of early articular cartilage degeneration was present in both partial medial and lateral meniscectomy patients at a minimum 5-year follow-up. Results support the use of cartilage-sensitive MRI as a noninvasive screening technique to evaluate cartilage changes after arthroscopic partial meniscectomy and may help to counsel the high-risk patient in regard to postoperative activity.

Fig. 1

Degenerative changes demonstrated by MRI in group MM and group LM

Fig. 2

Magnetic resonance imaging of 26-year-old male 5.4 years status-post partial lateral meniscectomy. A retear of the lateral meniscal body is noted by the fluid imbibition present in the meniscal remnant (arrow)

Fig. 3

(a) Magnetic resonance imaging of a 39-year-old patient 10.5 years after partial medial meniscectomy. This image demonstrates partial thickness articular wear over the medial tibial plateau (straight arrow) with a small marginal osteophyte (curved arrow). In contrast, the articular cartilage over the lateral tibial plateau is full-thickness without wear. (b) Magnetic resonance imaging (sagittal fast spin echo) image of the same patient noted in (a) This image demonstrates the presence of degenerative meniscal remnant (curved arrow), anterior marginal osteophytes (short straight arrow), and moderate central articular cartilage wear over the medial tibial plateau (long straight arrow)

Fig. 4

MRI cartilage appearance in medial compartment joint surfaces of group MM (MTP and MFC) versus lateral compartment joint surfaces of group LM (LTP and LFC)

Fig. 5

(a) and (b) Magnetic resonance imaging of 26-year-old patient 7 years after lateral meniscectomy. This image demonstrates near full-thickness articular cartilage loss over the posterior margin of the lateral tibial plateau (straight arrow), with a small degenerative lateral meniscal remnant adjacent to the scarred fascicle (curved arrow). Subpanel B demonstrates the slight extrusion of the meniscal remnant (arrow) present

Fig. 6

Magnetic resonance imaging of 26-year-old patient 10.3 years status-post after partial medial meniscectomy. This image demonstrates a small degenerative meniscal remnant that is extruded into the medial gutter (curved arrow). Note the subchondral sclerosis over the medial tibial plateau (straight arrows), as well as moderate articular cartilage wear over the weight-bearing area of the medial compartment

Fig. 7

Magnetic resonance imaging of a 30-year-old patient 11 years after partial lateral meniscectomy. This image demonstrates moderate wear of the articular cartilage over the lateral compartment with small marginal osteophytes (arrow)