Relationship between Severity of Varus Osteoarthritis of the Knee and Contracture of Medial Structures.

BACKGROUND: Knees with severe varus osteoarthritis can develop medial structure contracture. However, there is no report on the relationship between severity of varus deformity and contracture of the medial structure. We aimed to determine the threshold angle that could be corrected in proportion to the width of medial osteophyte removal and to examine correction differences between angles larger and smaller than the threshold angle in total knee arthroplasty. METHODS: This study included 27 varus osteoarthritic knees scheduled for total knee arthroplasty (TKA). A navigation system was used to measure hip-knee-ankle angle (HKA) in all knees at maximum extension and 30˚ and 60˚ flexion, before and after osteophyte removal and with and without external 10 N-m valgus torque loads. Subsequently, resected osteophyte widths were measured. Mean correction angle per 1 mm of osteophyte removal was calculated, and the threshold angle was calculated with the receiver operating characteristic curve. HKA differences were compared against deformities larger and smaller than the threshold angle. RESULTS: Mean osteophyte width was 7.1±2.20 mm. Osteophyte removal produced a mean 3.1° correction, which equaled a 0.4° correction per 1 mm of osteophyte width removal. The varus deformity threshold angle was 9.5°. However, when comparing groups with angles larger and smaller than the threshold angle, there was no significant difference in HKA difference between each step and flexion angle. CONCLUSIONS: The threshold angle for expected correction with medial osteophyte removal was 9.5˚. However, because there were no differences in correction between those with angles larger or smaller than this, medial structure contracture seemed to be unrelated to the severity of deformity.

An Isolated Iliac Wing Stress Fracture in a Male Marathon Runner: A Case Report.

CASE: A 49-year-old man, who had started jogging 3 months before his first participation in a marathon race, presented with acute pain and difficulty walking that began during the marathon race. Tumors and bone metabolism factors were ruled out by blood examination and various imaging findings. Isolated iliac wing fatigue fracture was diagnosed and treated with conservative therapy. CONCLUSION: This is the first English-literature report we know of an isolated iliac wing stress fracture in a male marathon runner without underlying disease. Our study highlights the importance of considering this rare fracture when diagnosing patients presenting with iliac pain.

Effect of Medial Osteophyte Removal on Correction of Varus Deformity in Total Knee Arthroplasty.

BACKGROUND: To restore neutral limb alignment in total knee arthroplasty (TKA), the procedure usually starts with removing osteophytes in varus osteoarthritic knees. However, the exact effect on alignment correction is unknown. The purpose of this study was to determine the effect of osteophyte removal alone during TKA for varus knees on correction of limb alignment on the coronal plane. METHODS: Fifteen knees with medial osteoarthritis and varus malalignment scheduled for TKA were studied. After registration in a navigation system, each knee was tested at maximum extension, and at 30, 40, and 60 degrees of flexion, before and after osteophyte removal. External loads of 10 N·m valgus torque at each angle and in both states were applied. Later, the widths of the resected osteophytes were measured. RESULTS: The average preoperative hip-knee-ankle angle was -14.2 degrees. The average width of osteophytes was 7.6 mm in the femur and 5.3 mm in the tibia. Angle corrections after osteophyte removal were 3.4 degrees at maximum extension, 3.4 degrees at 30 degrees flexion, and 3.6 degrees at 60 degrees flexion; the difference was significant for all angles. There was a positive correlation between osteophyte width and the degree of angle correction at 30 degrees. CONCLUSION: At 30 degrees of knee flexion, osteophyte width was correlated with the degree of angle correction on the coronal plane in TKA. The degree of angle correction per 1 mm of width of removed osteophytes was 0.4 degrees.

Influence of Total Knee Arthroplasty on Hip Rotational Range of Motion.

BACKGROUND: Total knee arthroplasty (TKA) aims to correct the rotation, as well as the alignment and articulation, of the osteoarthritic knee. We hypothesized that, in addition to improving knee kinematics, TKA affects hip rotational movement. The objective of this study was to evaluate variation in lower extremity alignment and hip rotational range of motion (ROM) after TKA. METHODS: A total of 47 patients (53 knees) with primary varus knee osteoarthritis who were scheduled for primary TKA at our center were enrolled. Hip rotational ROM was measured with the patient in supine position with 90° flexion of the hip and knee before and 3 weeks after TKA. Plain radiography and computed tomography were used to compare variations in tibial axis alignment and femoral axis alignment after bone resection, which was defined as changes in the joint lines of the distal femur and the proximal tibia. RESULTS: Average internal ROM, and the sum of internal and external hip rotational ROM, increased significantly; however, external hip rotational ROM did not significantly differ after TKA. Imaging findings showed that the axis of the lower leg externally rotated by 2.5°, with a 4° internal rotation of the distal femur and a 6.5° correction of the varus deformity. CONCLUSION: TKA changed the neutral position of hip rotational movement and increased hip rotational ROM.

A computed-tomography-scan-based template to place the femoral component in accurate rotation with respect to the surgical epicondylar axis in total knee arthroplasty.

BACKGROUND: Femoral rotational alignment is considered an essential factor for total knee arthroplasty because malrotation of femoral components results in poor outcomes. To obtain proper alignment, we developed a superimposable computed tomography (CT) scan-based template to intraoperatively determine the accurate surgical epicondylar axis (SEA), and evaluated the effectiveness of this CT template. METHODS: In the experimental group (n=55), three serial slices of CT images, including medial and lateral epicondyles, were merged into a single image, and SEA was overlaid. SEA was traced onto an image of an assumed distal femoral resection level; this combined image was then printed out onto a transparent film as a CT template. Following a distal femoral resection in TKA, SEA was duplicated onto the femoral surface. Thereafter, the posterior condyle was resected parallel to this SEA. In the control group (n=53), posterior condyles were resected at three degrees of the external rotation from the posterior condylar line (PCL). A posterior condylar angle (PCA) between PCL of the femoral component and SEA was postoperatively evaluated. Positive values indicated external rotation of the femoral component from the SEA. RESULTS: In the experimental group, PCA was 0.01°±1.61°, and three cases were considered as outliers (greater than three degrees or less than -3 degrees). Conversely, in the control group, PCA was 0.10°±2.4°, and 12 cases were considered as outliers. Consequently, dispersion of PCA data was significantly smaller in the experimental group (P=0.004). CONCLUSIONS: The CT template accurately determined intraoperative SEA.

Bone morphological factors influencing cartilage degeneration in the knee.

OBJECTIVES: Morphological features of the distal femur and proximal tibia associated with cartilage degeneration are unknown. This study aimed to elucidate local anatomical parameters of the knee which correlate with articular cartilage degeneration using MRI T1ρ mapping. METHODS: This study involved 200 subjects with knee pain (mean age, 48.7 years; range, 14-80 years) with no severe osteoarthritic changes on plain X-ray. T1ρ values were measured in the regions of interest on the surface layer of the cartilage on mid-coronal images of the femorotibial joint. Assessment of medial and lateral posterior tibial slope (MTS, LTS) and medial and lateral femoral condylar offset ratio (MFCOR, LFCOR) was performed using sagittal proton density-weighted imaging. Morphological assessment of posterior root and horn of menisci was also performed according to a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) of the knee. RESULTS: Multiple regression analysis revealed that a decrease in MTS was associated with increased T1ρ values in the medial tibia, independent of age, osteoarthritic changes on plain X-ray, femur-tibia angle (FTA), and posterior medial meniscal lesions. CONCLUSIONS: Shallow MTS correlates with cartilage degeneration in symptomatic patients. This parameter could help in understanding the etiology of osteoarthritis in the early stage. Future kinematic studies will be needed to confirm our findings.

The Ilizarov Mini-External Fixator for the Treatment of First Metatarsal Fracture: A Case Report.

Forefoot fractures are frequently accompanied by severe soft tissue damage. Therefore, treatment should focus not only on fractures but also on soft tissue damage, for which external fixation can be used as a surgical option. A 63-year-old woman presented to the emergency clinic of our hospital with forefoot pain after a motorcycle accident. Comminuted fracture of the proximal part of the metatarsal was diagnosed. Because of the swollen foot and fracture comminution, an operation using the Ilizarov mini external fixator was performed to prevent further damage to the soft tissue. Weight-bearing was permitted seven weeks after the operation, and the extraction of the apparatus was performed nine weeks postoperatively. One year later, the patient had no pain and had returned to ballroom dancing, a hobby which she performed five days a week, with no difficulties. Our results suggest that the Ilizarov mini external fixator should be considered not only for temporary treatment, but also for the entire duration of treatment of first metatarsal fractures associated with severe soft tissue damage.

Superior Dislocation of the Patella in a Young Woman without Osteophytes: A Case Report.

Superior dislocation of the patella without patellar ligament injury is an extremely rare condition. A review of the English-language literature found only 23 reported cases. In addition, the primary factor for dislocation in most of these cases was considered to be osteophytes in the inferior pole of the patella and the anterior surface of the femoral condyle; only 1 case had no osteophytes. We treated a 19-year-old woman who sustained a painful locking of the left knee after colliding with a friend. Plain radiography and computed tomography showed superior-lateral dislocation of the patella and an interlocking between notches in the inferior pole of the patella and the anterior surface of the femoral condyle. Closed reduction without sedation was performed without difficulty, and the patient was able to walk home without pain. After 1 week, the knee was without problems. The patient had no osteophytes in the knee and had no other common risk factors, such as patella alta, ligamentous laxity, genu recurvatum, and paralytic disorders. After a comparison with previously reported cases of superior patella dislocation, we concluded that the primary factor in the present case might have been a different condition.