Original Article
The Relationship Between the MPP Test and Arthroscopically Found Medial Patellar Plica Pathology

https://doi.org/10.1016/j.arthro.2007.06.016Get rights and content

Purpose: This study investigated whether the mediopatellar plica (MPP) test developed by the authors could be used preoperatively to predict MPP pathology found at arthroscopy. Methods: Between January 1999 and August 2004, 65 patients (66 knees, group I) with anteromedial knee pain were examined using the MPP test before undergoing an arthroscopic procedure. In the control group, 101 patients (106 knees, group II) with lateral tibiofemoral joint line pain were examined by the MPP test. After arthroscopic excision of a thickened MPP, the visual analogue scale and the Lysholm scoring scale were recorded during follow-up. Results: Of the 172 knees evaluated, the sensitivity, specificity, and positive and negative predictive value for the MPP test were 89.5%, 88.7%, 78.7%, and 94.4%, respectively. The accuracy value was 89.0%. Thirteen knees (7.6%) were categorized as false positives, 7 knees had fat pad synovial fringe entrapments, 5 knees had localized synovitis, and 1 knee had a focal cartilage lesion on the medial femoral condyle. In 53 knees diagnosed with pathologic MPP entrapment in group I, the mean postoperative VAS was 1.3 (range, 0 to 4) and the mean postoperative Lysholm score was 91.4 (range, 74 to 100), while all knees showed a negative MPP test after the mean follow-up of 48.1 months (range, 24 to 96 months). Conclusions: The MPP test is reliable to predict the pathologic MPP entrapment, and arthroscopic excision of pathologic MPP shows satisfactory clinical results. Level of Evidence: Level III, diagnostic study of nonconsecutive patients without consistently applied gold standard.

Section snippets

Methods

Between January 1999 and August 2004, 65 patients (66 knees) in group I with anteromedial knee pain who underwent subsequent arthroscopic procedures were examined preoperatively using the MPP test. Patients who did not respond to conservative treatments (such as supervised physiotherapy, including quadriceps-strengthening and hamstring-stretching exercise daily, activity modification, and non-steroidal anti-inflammatory medications for 6 months) were included, and patients were excluded if they

Accuracy of MPP Test

The patients in both groups were similar with regard to age and gender.

In the 64 knees that showed a positive MPP test preoperatively, 51 knees (79.7%) had pathologic MPP entrapment, 7 knees (10.9%) had fat pad synovial fringe entrapments without pathologic MPP, and 5 knees (7.8%) had localized synovitis on the medial peripatellar region. One knee (1.6%) showed a focal cartilage defect lesion on the medial femoral condyle.

In the 108 knees that had a negative MPP test preoperatively, 6 knees

Discussion

There was close correlation between the MPP test and arthroscopically found pathologic MPP entrapment in our study. A “positive MPP test” predicted “arthroscopically found MPP entrapment” with 78.8% accuracy and “all cases with no MPP entrapment by surgical resection” showed a “negative MPP test” at follow-up.

On physical examination, symptomatic MPP can often be palpated, demonstrating a tender, band-like structure paralleling the medial border of the patellar at 30° of flexion on knee motion.

Conclusions

A MPP test may be used as an accurate and noninvasive method for the detection of arthroscopically found MPP entrapment, and arthroscopic excision of pathologic MPP shows satisfactory clinical results.

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    The authors report no conflicts of interest.

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