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

OBJECTIVE: To measure and compare medial proximal tibial angle (MPTA) of lower limbs under different axial rotation angles(neutral position, 30° internal rotation, 30° external rotation) on the load position radiographs, and explore changes and significance of MPTA measured within and between groups of tibia at different axial rotation positions. METHODS: From January 2018 to December 2018, 40 patients with knee osteoarthritis (KOA) were selected, with a total of 80 limbs, including 12 males and 28 females, aged from 29 to 73 years old with an average of (59.6±12.7) years old. Full length radiographs of the lower limbs were taken on neutral tibia position, 30° internal rotation and 30° external rotation, respectively. MPTA was measured and the results were compared between groups and within groups. RESULTS: MPTA measured on the left lower extremity of neutral tibia, 30° internal rotation and 30° external rotation were (86.08±2.48) °, (88.62±2.94) ° and (83.47±3.10) °, respectively. MPTA measured on the right lower limb were (86.87±1.97) °, (89.02±2.39) ° and (83.80±2.77) °, respectively, and there were no significant difference in MPTA measured between rotation angle group (P>0.05). While there were statistical difference in MPTA on the same limb between groups (P<0.05). On 30° internal rotation, MPTA of left and right lower limbs increased by (2.54±1.74) ° and (2.15±1.78) ° compared with tibia neutral position. On 30° external rotation, MPTA of left and right lower limbs decreased (2.61±2.03) ° and (3.07±1.75) ° compared with tibial neutral position. CONCLUSION When a full-length X-ray film is taken on the weight-bearing position of both lower limbs, if there is axial rotation or external rotation of tibia, MPTA will increase or decrease compared with neutral position, which may cause a certain degree of deviation in clinical operation based on the accurate measurement of MPTA. However, the extent to which this bias affects the clinical operation effect remains to be verified. In addition, limited by the total number of samples and the number of measurement groups, whether there is a linear relationship between MPTA deviation and tibial axial rotation needs to be further studied.
Male ; Female ; Humans ; Adult ; Middle Aged ; Aged ; Tibia/surgery* ; Lower Extremity ; Osteoarthritis, Knee/surgery* ; Radiography ; Osteotomy/methods* ; Knee Joint/surgery* ; Retrospective Studies

BACKGROUND: Knee osteoarthritis is highly prevalent, especially among the elderly. However, its risk factors have not been well identified, especially in the Korean population. This study aimed to assess the epidemiologic characteristics and risk factors of knee osteoarthritis in the Korean population. METHODS: Data of 2,280 (1,295 women) participants of the 2013 Korea National Health and Nutrition Examination Survey aged ≥50 years who underwent knee radiography were analyzed. According to the American College of Rheumatology clinical/radiographic classification criteria, knee osteoarthritis was defined as knee pain and radiographic knee osteoarthritis. The association between risk factors and knee osteoarthritis was analyzed using the chi-square test and binominal logistic regression. RESULTS: The participants had an average age of 62.6 years; 56.8% of them were women. The average body mass index was 24.2 kg/m2, and 296 (13%) participants were diagnosed with knee osteoarthritis. After adjustment for multiple risk factors, age of ≥65 years (adjusted odds ratio [OR], 2.552; 95% confidence interval [CI], 1.868–3.486), female sex (OR, 2.050; 95% CI, 1.275–3.295), obesity (body mass index, ≥25.0 kg/m2; OR, 1.563; 95% CI, 1.191–2.051), hypertension (OR, 1.394; 95% CI, 1.052–1.846), low educational level (lower than or equal to elementary school: OR, 4.761; 95% CI, 2.131–10.635; middle school: OR, 3.184; 95% CI, 1.375–7.369), and low strength exercise frequency (<2 times/wk; OR, 1.829; 95% CI, 1.202–2.784) increased the risk of knee osteoarthritis. CONCLUSION: Old age, sex, obesity, hypertension, low educational level, and low strength exercise frequency were found to be risk factors for knee osteoarthritis.
Aged ; Body Mass Index ; Classification ; Epidemiology ; Female ; Humans ; Hypertension ; Knee ; Korea ; Logistic Models ; Nutrition Surveys ; Obesity ; Odds Ratio ; Osteoarthritis ; Osteoarthritis, Knee ; Prevalence ; Radiography ; Rheumatology ; Risk Factors

A 20-year-old National Serviceman presented with left knee pain and swelling after training for his physical fitness test. Lateral knee radiography and magnetic resonance (MR) imaging showed patellar tendon-lateral femoral condyle friction syndrome (PT-LFCFS), on a background of patella alta and patellar malalignment. The patient was treated non-operatively with a course of physiotherapy and given advice on rest and activity modification. PT-LFCFS is a less well-recognised but important cause of anterior knee pain and represents an entity in a spectrum of disorders related to patellofemoral instability. We herein discuss the MR imaging findings specific to and associated with this condition, as well as briefly describing treatment options. In addition, we showcase a range of commonly encountered abnormalities that affect the infrapatellar fat pad and briefly discuss their specific MR imaging findings.
Adult ; Arthralgia ; diagnostic imaging ; Female ; Femur ; diagnostic imaging ; Humans ; Knee ; diagnostic imaging ; Knee Injuries ; diagnostic imaging ; therapy ; Knee Joint ; diagnostic imaging ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pain ; diagnostic imaging ; Patella ; diagnostic imaging ; Patellar Ligament ; diagnostic imaging ; Physical Therapy Modalities ; Radiography ; Young Adult

OBJECTIVE: To find factors affecting hip and femoral deformities in children with spastic cerebral palsy (CP) by comparing various clinical findings with imaging studies including plain radiography and computed tomography (CT) imaging. METHODS: Medical records of 709 children with spastic CP who underwent thorough baseline physical examination and functional assessment between 2 to 6 years old were retrospectively reviewed. Fifty-seven children (31 boys and 26 girls) who had both plain radiography of the hip and three-dimensional CT of the lower extremities at least 5 years after baseline examination were included in this study. RESULTS: The mean age at physical examination was 3.6 years (SD=1.6; range, 2–5.2 years) and the duration of follow-up imaging after baseline examination was 68.4 months (SD=22.0; range, 60–124 months). The migration percentage correlated with motor impairment and the severity of hip adductor spasticity (R1 angle of hip abduction with knee flexion). The femoral neck and shaft angle correlated with the ambulation ability and severity of hip adductor spasticity (R1 and R2 angles of hip abduction with both knee flexion and extension). CONCLUSION: Hip subluxation and coxa valga deformity correlated with both dynamic spasticity and shortening of hip adductor muscles. However, we found no correlation between femoral deformities such as femoral anteversion, coxa valga, and hip subluxation.
Bone Anteversion ; Cerebral Palsy* ; Child* ; Congenital Abnormalities* ; Coxa Valga ; Femur Neck ; Follow-Up Studies ; Hip Dislocation ; Hip* ; Humans ; Knee ; Lower Extremity ; Medical Records ; Muscle Spasticity* ; Muscles ; Physical Examination ; Radiography ; Retrospective Studies ; Walking

BACKGROUNDDiscoid lateral meniscus was a common meniscal dysplasia and was predisposed to tear. There were some anatomical knee variants in patients with discoid lateral meniscus. The aim of this study was to analyze the relationship between anatomical knee variants and discoid lateral meniscal tears.

METHODSThere were totally 125 cases of discoid lateral meniscus enrolled in this study from February 2008 to December 2013. Eighty-seven patients who underwent arthroscopic surgery for right torn discoid lateral meniscus were enrolled in the torn group. An additional 38 patients who were incidentally identified as having intact discoid lateral menisci on magnetic resonance imaging (MRI) findings were included in the control group. All patients were evaluated for anatomical knee variants on plain radiographs, including lateral joint space distance, height of the lateral tibial spine, height of the fibular head, obliquity of the lateral tibial plateau, squaring of the lateral femoral condyle, cupping of the lateral tibial plateau, lateral femoral condylar notch, and condylar cutoff sign. The relationship between anatomical variants and meniscal tear was evaluated. These anatomical variants in cases with complete discoid meniscus were also compared with those in cases with incomplete discoid meniscus.

RESULTSThere were no significant differences between the two groups in lateral joint space distance (P = 0.528), height of the lateral tibial spine (P = 0.927), height of the fibular head (P = 0.684), obliquity of the lateral tibial plateau (P = 0.672), and the positive rates of squaring of the lateral femoral condyle (P = 0.665), cupping of the lateral tibial plateau (P = 0.239), and lateral femoral condylar notch (P = 0.624). The condylar cutoff sign was significantly different between the two groups, with the prominence ratio in the torn group being smaller than that in the control group (0.74 ± 0.11 vs. 0.81 ± 0.04, P = 0.049). With the decision value of the prominence ratio (0.78) in predicting discoid lateral meniscal tear, the sensitivity and specificity of the cutoff sign were 66% and 71%, respectively. There were no significant differences in radiographic variants between the complete and incomplete discoid lateral meniscal groups.

CONCLUSIONSThe condylar cutoff sign observed on the tunnel view of the radiograph is helpful in predicting meniscal tear in adult patients with discoid lateral meniscus. As for these patients, further MRI test is recommended.

Adolescent ; Adult ; Aged ; Arthroscopy ; Child ; Female ; Humans ; Knee Injuries ; diagnosis ; Knee Joint ; anatomy & histology ; surgery ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Radiography ; Retrospective Studies ; Young Adult

The alignment of lower extremities is an important consideration in many clinical situations, including fracture reduction, high tibia osteotomy, total knee arthroplasty, and deformity correction. Mal-alignment of lower extremities is not only a simple cosmetic problem, but it can also produce pain, limp, and early degenerative arthritis. An assessment of lower extremity alignment, including its location and magnitude of deformity, can be achieved via mal-alignment test and mal-orientation test, using a lower extremity standing full-length radiography. Proper evaluation allows the surgeon to determine an effective treatment plan for deformity correction.
Arthroplasty, Replacement, Knee ; Congenital Abnormalities* ; Lower Extremity* ; Osteoarthritis ; Osteotomy ; Radiography ; Tibia

PURPOSE: The fixed flexion view (FFV) of the knee is considered useful for evaluating the joint space when assessing the severity of osteoarthritis (OA) of the knee. To clarify the usefulness of FFV for evaluation of the joint space and severity of knee OA, this study evaluated changes in the joint space on the FFV and standing extended view (SEV) in patients with knee OA. MATERIALS AND METHODS: The SEV and FFV images were acquired in 567 patients (1,102 knees) who visited the hospital with a chief complaint of knee joint pain. Medial joint space width (MJSW) and Kellgren-Lawrence (K-L) classification assessed using the SEV and FFV images were compared. RESULTS: Mean MJSW was significantly smaller when assessed on the FFV than on the SEV (3.02±1.55 mm vs. 4.31±1.30 mm; p<0.001). The K-L grade was the same or higher on the FFV than on the SEV. CONCLUSIONS: The FFV is more useful than the SEV for evaluating the joint space in OA knees. Treatment strategies in patients with knee OA should be determined based on routinely acquired FFV images.
Asian Continental Ancestry Group ; Classification ; Humans ; Joints ; Knee Joint ; Knee ; Osteoarthritis ; Radiography

PURPOSE: To identify the accuracy of postoperative implant alignment in minimally invasive surgery total knee arthroplasty (MIS-TKA), based on the degree of varus deformity. MATERIALS AND METHODS: The research examined 627 cases of MIS-TKA from November 2005 to December 2007. The cases were categorized according to the preoperative degree of varus deformity in the knee joint in order to compare the postoperative alignment of the implant: less than 5degrees varus (Group 1, 351 cases), 5degrees to less than 10degrees varus (Group 2, 189 cases), 10degrees to less than 15degrees varus (Group 3, 59 cases), and 15degrees varus or more (Group 4, 28 cases). RESULTS: On average, the alignment of the tibial implant was 0.2+/-1.4degrees, 0.1+/-1.3degrees, 0.1+/-1.6degrees, and 0.3+/-1.7degrees varus, and the tibiofemoral alignment was 5.2+/-1.9degrees, 4.7+/-1.9degrees, 4.9+/-1.9degrees, and 5.1+/-2.0degrees valgus for Groups 1, 2, 3, and 4, respectively, in the preoperative stage, indicating no difference between the groups (p>0.05). With respect to the accuracy of the tibial implant alignment, 98.1%, 97.6%, 87.5%, and 86.7% of Groups 1, 2, 3, and 4, respectively, had 0+/-3degrees varus angulation, demonstrating a reduced level of accuracy in Groups 3 and 4 (p<0.0001). There was no difference in terms of tibiofemoral alignment, with 83.9%, 82.9%, 85.4%, and 86.7% of each group, respectively, showing 6+/-3degrees valgus angulation (p>0.05). CONCLUSION: Satisfactory component alignment was achieved in minimally invasive surgery in total knee arthroplasty, regardless of the degree of varus deformity.
Aged ; Arthroplasty, Replacement, Knee/*methods ; Bone Anteversion/complications/*radiography ; Bone Malalignment/etiology/*radiography ; Female ; Humans ; Joint Deformities, Acquired/*surgery ; Knee Joint/radiography/*surgery ; Knee Prosthesis ; Male ; Middle Aged ; Minimally Invasive Surgical Procedures/*methods ; Osteoarthritis, Knee/complications/radiography/*surgery ; Postoperative Period ; Preoperative Period ; Range of Motion, Articular ; Tibia/surgery ; Treatment Outcome

Synovial osteochondromatosis (SO) can occur idiopathic or secondary to osteoarthritis. SO can be easily diagnosed with plain film radiography and clinical findings. In case of disabling osteoarthritis, total knee arthroplasty and removal of all corpora libra are indicated. We present a 71-year-old woman with significant osteoarthritis and severe SO intra-articular and in the suprapatellar bursa of the right knee. Total knee arthroplasty, extraction of the loose bodies, and partial synovectomy were performed. During a 2.5-year follow-up, the patient regained full function of her affected knee and there was no recurrence of SO. We choose to present this case to show the extensiveness SO can occur in. Our advice is to remove all the loose bodies carefully to prevent damage to the prosthesis. During follow-up, special attention should be paid to prevent recurrence of SO. When recurrence is associated with rapid growth or destruction of joints, malignant reoccurrence must be considered.
Aged ; Arthroplasty* ; Chondromatosis, Synovial* ; Female ; Follow-Up Studies ; Humans ; Joints ; Knee* ; Osteoarthritis ; Prostheses and Implants ; Radiography ; Recurrence