BACKGROUND: The correlation between the morphological structure of the patellofemoral joint (PFJ) and the severity of knee joint osteoarthritis (KOA) remains uncertain. This study aims to investigate the correlation between the severity of knee joint osteoarthritis and the alignment of patellofemoral and patellar height on radiographs. METHODS: This multi-center, retrospective study analyzed the magnetic resonance imaging (MRI) scans and anteroposterior radiographs of 534 adult outpatients with KOA. To evaluate the radiographic severity of KOA, anteroposterior radiographs of the knee and the Kellgren-Lawrence (K-L) grade were used. Knee MRI scans were used to measure the patellar length ratio (PLR), sulcus angle (SA), lateral patellar tilt angle (LPTA), and the distance between tibial tuberosity and trochlear groove (TT-TG). We examined the association between the configuration of the PFJ, arrangement, and harshness of the KOA. Information on participants' demographics, such as age, sex, side, height, and weight, was collected. A chi-squared test was used for the correlation of radiographic severity of KOA with sex and the affected side. Spearman correlation was used for patellofemoral alignment or morphology and the radiographic severity of lateral KOA. Multiple linear regression models were used for the association between LPTA, SA, TT-TG, and severity of KOA after accounting for demographic variables. RESULTS: The study comprised of 534 patients; of these, 339 (63%) were female. A total of 586 knees were evaluated in this study. Age showed a strong positive correlation with KOA severity ( r  = 0.516, P <0.01), whereas LPTA showed a strong negative correlation ( r  = -0.662, P <0.01). Additionally, SA ( r  = 0.616, P <0.05), and TT-TG showed a strong positive correlation ( r  = 0.770, P <0.01) with tibiofemoral osteoarthritis (TFOA) severity. Multiple linear regression analysis indicated that knee osteoarthritis severity (β = -2.946, P <0.001) and side (β = -0.839, P  = 0.001) was associated with LPTA; knee osteoarthritis severity (β = 5.032, P <0.001) and age (β = -0.095, P <0.001) was associated with SA; knee osteoarthritis severity (β = 2.445, P <0.001), sex (β = -0.326, P  = 0.041), body mass index (β = -0.061, P  = 0.017) and age (β = -0.025, P <0.001) was associated with TT-TG. CONCLUSION Radiographic severity of KOA was positively associated with age, SA, and TT-TG but negatively associated with LPTA.
Humans ; Female ; Male ; Osteoarthritis, Knee/pathology* ; Middle Aged ; Retrospective Studies ; Aged ; Patellofemoral Joint/pathology* ; Magnetic Resonance Imaging ; Adult ; Patella/pathology* ; Radiography

PURPOSE: The pattern of symptoms of knee osteoarthritis has been thought to be indicative of specific compartment involvement. This study investigated whether there was a true correlation between patellofemoral joint (PFJ) symptoms and unicompartmental patellofemoral arthritis. MATERIALS AND METHODS: A prospective analysis of 34 patients rendered to be suffering from PFJ osteoarthritis and subsequently undergoing unicompartmental patellofemoral arthroplasty (PFA) was performed. A control cohort of 32 patients suffering from medial tibiofemoral joint (MTFJ) osteoarthritis was included in the analysis. Four questions derived from the Oxford knee score questionnaire, traditionally deemed to be indicative of PFJ osteoarthritis, were combined to create a PFJ subscore and statistically analyzed for their potential relationship with PFJ osteoarthritis and outcomes following PFA. RESULTS: The PFJ subscore indicated slightly worse pathology in patients undergoing PFA compared to MTFJ replacement, but the difference was not significant (9.7 and 9.6, respectively; p=0.851). The improvement in PFJ symptoms was higher in those undergoing PFA compared to MTFJ surgery; however, the difference was not statistically significant (3.7 and 2.2 respectively, p=0.074). CONCLUSIONS: We were unable to prove that these symptoms were predictive of PFJ pathology in the preoperative setting, nor were they useful in interpreting which symptoms would likely improve following PFA.
Arthritis ; Arthroplasty ; Cohort Studies ; Humans ; Joints ; Knee ; Osteoarthritis ; Osteoarthritis, Knee ; Patellofemoral Joint ; Pathology ; Prospective Studies

PURPOSE: The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI). MATERIALS AND METHODS: MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured. RESULTS: With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, <15°) was 14.6° and the bisect offset (normal value, <65%) was 65%, while the Caton-Deschamps index was 1.34 (normal range, 0.6 to 1.3). With the knee extended and quadriceps relaxed, the mean Caton-Deschamps index was 1.31. CONCLUSIONS: MRI scanning of the knee in extension with the quadriceps contracted leads to elevated patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction.
Humans ; Knee ; Magnetic Resonance Imaging ; Patella ; Patellofemoral Joint ; Pathology

OBJECTIVETo determine whether anterior knee pain and/or radiological evidences of degeneration of the patellofemoral joint influence the outcome of unicompartmental knee arthroplasty (UKA).

METHODSBetween January 2006 and December 2010, 95 consecutive patients (100 knees) with unicompartmental knee osteoarthritis were treated with Oxford UKA, including 34 males and 61 females. The mean age was 68.2 years (range, 55-82 years). The average Body Mass Index was 26.3 kg/m(2)(range, 24-28 kg/m(2)). Pre-operative there were 43 knees (43.0%) with anterior knee pain and 57 knees (57.0%) without it. Pre-operative radiological status of the patellefemoral joint were defined using Ahlback and Altman systems. The pre- and post-operative results of Oxford Knee Score (OKS), American Knee Society Score (AKS) and Western Ontario and Macmaster (WOMAC) were compared using paired t-test, the results between different groups were compared using grouped t-test.

RESULTSAll cases were followed up for average 50 months (24-84 months). At the last follow-up, none had complications of infection, fat embolism, deep vein thrombosis, malposition of prosthesis, dislocation or loosing. The mean femoral component alignment was -0.7° ± 5.2° (valgus/varus), -0.8° ± 4.5°(flexion/extension); the mean tibial component alignment was -0.1° ± 2.2°(valgus/varus), -0.4° ± 2.4° (flexion/extension). The clinical outcomes were significantly improved compared with pre-operation regardless of presence (OKS: t = 19.04, P < 0.01; AKS knee:t = 38.56, P < 0.01;AKS function:t = 39.29, P < 0.01;WOMAC:t = 43.22, P < 0.01) or absence (OKS: t = 31.57, P < 0.01; AKS knee:t = 40.34, P < 0.01; AKS function:t = 43.62, P < 0.01; WOMAC: t = 47.06, P < 0.01) of anterior knee pain. The results were significantly improved compared with pre-operation (P < 0.01) regardless of whether degeneration of the patellofemoral joint. There was no statistically significant difference in outcome between patients with evidence of degeneration in the medial patellofemoral joint and those without (P > 0.05) . Patients with lateral patellofemoral degeneration had a worse score than those without, OKS (t = 2.56, P = 0.01) and WOMAC (t = 2.20, P = 0.03) by the Altman score, OKS (t = 2.29, P = 0.02) by the Ahlback score. For AKS measures there was no statistically significant difference in outcome (P > 0.05) .

CONCLUSIONSNeither anterior knee pain nor radiological evidence of medial patellofemoral joint degeneration would influnence the outcome of UKA, lateral patellofemoral joint degeneration have an increased risk of a poor result.

Aged ; Aged, 80 and over ; Arthralgia ; pathology ; Arthroplasty, Replacement, Knee ; Female ; Humans ; Male ; Middle Aged ; Osteoarthritis, Knee ; surgery ; Patellofemoral Joint ; pathology ; Treatment Outcome

Bone single photon emission computed tomography(SPECT) of the knees has been shown to be of diagnostic value for the investigation of intemal derangement of knees(IDK). This study compared bone SPECT and magnetic resonance image(MRI) with arthroscopic findings for the diagnosis of IDK. Fifty patients who had been performed arthroscopy in Seoul National University Hospital from January 1997 to September 1997 were studied with both the modalities preoperatively. There were 38 meniscal injuries, 26 cruciate ligament injuries and 8 cases of patellofemoral joint problems. In view of SPECT, the most remarkable results were from meniscal tears. In meniscal tears, the diagnostic values of SPECT were 89.5% of sensitivity, 66.7% of specificity, 84% of diagnostic accuracy, which were comparable to those of MRI, 97.4%, 91.7% and 96%, respectively. But SPECT showed inferior diagnostic values in cruciate ligament injuries. For anterior knee pain, SPECT was more sensitive than MRI for the detection of pathology. And for functionally related cases, such as ACL impingement to intercondylar notch, SPECT was far more valuable than MRI. Bone SPECT will not provide the anatomical detail of MRI but seems to be a useful tool for the detection of wide range of knee disorders including IDK. Further research is justified to investigate the precise role of bone SPECT in clinical practice and its value in relation to MRI.
Arthroscopy ; Diagnosis ; Humans ; Knee* ; Ligaments ; Magnetic Resonance Imaging* ; Patellofemoral Joint ; Pathology ; Sensitivity and Specificity ; Seoul ; Tomography, Emission-Computed, Single-Photon*