Diagnostic Criteria to Differentiate Medial Meniscal Injury from Degenerative Changes on 99mTc-MDP Knee SPECT in Patients with Chronic Knee Pain / 대한핵의학회잡지

PURPOSE: In patients with chronic knee pain, the diagnostic performance of 99mTc-MDP knee SPECT for internal derangement of knee is deteriorated due to degenerative changes. In this study, we tried to establish diagnostic criteria to differentiate medial meniscal injury (MMI) from degenerative change (DC) when the uptake is increased in medial compartment. MATERIALS AND METHODS: A total of 49 knee SPECT of the patients with chronic (more than 3 months) knee pain, which showed increased 99mTc-MDP uptake in the medial compartment, were included in this study. The diagnosis was confirmed by arthroscopy. On knee SPECT, 3 diagnosic criteria for MMI were investigated. In Criterion I, MMI was diagnosed when crescentic uptake was observed in the medial tibial plateau. In Criterion II, crescentic uptake was further classified into anterior, mid, posterior, and diffuse patterns, according to the location of maximal uptake; and only crescentic mid, posterior, and diffuse patterns were diagnosed as MMI. In Criterion III, MMI was diagnosed when medial tibial plateau showed higher activity then medial femoral condyle. The diagnostic performance of the 3 criteria was compared. RESULTS: The sensitivity and specificity were 93% and 14% in Criterion I, 89% and 38% in Criterion II, and 75% and 67% in Criterion III, respectively. Criterion III had significantly improved diagnostic performance, especially, specificity. CONCLUSION: In this study, we established a practical diagnostic criterion to differentiate MMI from DC on knee SPECT. The result is helpful to improve the diagnostic value of knee SPECT as a screening test for chronic knee pain.

Incidence of Internal Derangement of Knee in the case of Total Knee Arthroplasty

PURPOSE: To evaluate the incidence and types of internal derangement of the knee, observed during total knee arthroplasty in patients with degenerative osteoarthritis and to correlate the findings with preoperative clinical presentations. MATERIALS AND METHODS: From January 1996 to January 2002, 435 patients(622 cases) with degenerative osteoarthritis who underwent total knee arthroplasty were analyzed for the presence of meniscal or cruciate ligament injuries. The type, site and patterns of injuries of the meniscus were recorded. Then the patients were categorized into group I; without meniscal injuries and group II; with meniscal injuries. Comparative analyses were also made between the two groups according to age, height, body weight, hospital for special surgery score(HSS score), the knee society clinical rating system(TKSCRS) score, and injuries of ACL and PCL. RESULTS: The medial meniscal injury is the most frequently involved type and was found in 288 cases(46.3%). Midportion to posterior horn location and midportion radial and posterior horn complex patterns showed the most cases in respect to site and pattern of meniscal injury. ACL injury was found in 48 cases while 55 cases showed PCL injury. Preoperative range of motion(I: 128.5 +/-9.7 degree, II: 114.8 +/-15.5 degree) and knee functional tests, such as, HSS score(I: 61.9 +/-14.0, II: 56.8 +/-14.9) and TKSCRS score(I: 97.3 +/-27.3, II: 81.1 +/-31.1) were significantly low in group II(p<0.05). Average age was 64.3 years in group I and 67.8 years in group II respectively. And age ranges were higher in group II(p<0.05). Injury of ACL and PCL were more common in group II. CONCLUSION: Meniscus injuries that were frequently seen in total knee arthroplasty have clinical relations to the patient 's ages, range of motion, function.