Factors affecting range of motion after total knee arthroplasty in patients with more than 120 degrees of preoperative flexion angle.

PURPOSE: The postoperative flexion angle reportedly shows a positive correlation with the preoperative flexion angle, but in some cases, the postoperative flexion angle decreases in patients with a large preoperative flexion angle. The purpose of this study was to investigate factors affecting the range of motion after total knee arthroplasty (TKA) in patients with a large preoperative flexion angle. METHODS: The study evaluated 120 knees with more than 120 degrees of preoperative flexion angle that underwent NexGen LPS-Flex mobile bearing. The groups with and without a reduction in the postoperative flexion angle were compared. Also, a logistic regression analysis was performed, where the presence or absence of a reduction in the postoperative flexion angle was the dependent variable and age, sex, body mass index (BMI), preoperative femorotibial angle (FTA), γ angle, δ angle, pre/postoperative change amount in posterior condylar offset (PCO), pre/postoperative change amount in joint line, and pre/postoperative change amount in patellar thickness were independent variables. RESULTS: Those with preoperative FTA of 186° or larger did not have a reduction in the postoperative flexion angle, compared with the angle of 185° or smaller. Those with δ angle of 83° or smaller also did not have a reduction in the postoperative flexion angle, compared with the angle of 84° or larger. CONCLUSIONS: Our results showed that preoperative FTA and δ angle had an impact on a reduction in the postoperative flexion angle. The installation angle of the tibial component in the sagittal plane is important.

A double patella-like condition secondary to synovial osteochondromatosis.

To our knowledge, this is the first case of synovial osteochondromatosis in a patient presenting with a double patella-like condition. The true duplication of the patella, which is called double patella, is extremely rare. In our case, the operative and histopathological findings showed that the double patella-like condition was secondarily induced by synovial osteochondromatosis. Synovial osteochondromatosis should be considered as a differential diagnosis for congenital double patella.

Total knee arthroplasty for neuropathic joint disease after severe bone destruction eroded the tibial tuberosity.

This article describes a patient in whom total knee arthroplasty was performed for neuropathic joint disease secondary to diabetes mellitus after severe bone destruction eroded the tibial tuberosity. At initial examination, radiographs of the knee showed bone destruction in the medial and anterior regions of the tibia, and fine bone fragments were seen in the joint. Conservative therapy was performed using a brace. However, bone destruction gradually advanced, and 10 months after the initial examination, radiographs of the knee showed bone destruction in the lateral condyle of the femur and advanced bone destruction of the anterior tibia; the tibial tuberosity was missing. It is rare for the tibial tuberosity in the anterior tibia to disappear. If this happens, reconstruction is difficult and total knee arthroplasty becomes complicated. For the bone defect in the tibia, cement was used to recreate the shape of the anterior surface of the tibia. It was possible to minimize the volume of bone resection and morphologically reconstruct the tibial tuberosity. The patient recovered quickly. At postoperative week 5, the patient was able to walk using a cane. Thirty-six months after total knee arthroplasty, knee extension was 0°, flexion was 120°, extension lag was 5°, knee score improved from 40 points to 94 points, and functional score improved from 20 points to 75 points. However, long-term implant stability needs to be carefully monitored.

An analysis of the medial patellofemoral ligament length change pattern using open-MRI.

Recently, for a recurrent patellar dislocation, medial patellofemoral ligament (MPFL) reconstruction has come to be commonly performed, yet the precise in vivo MPFL biomechanics still remains to be clarified. The purpose of this study was to analyze the length change pattern of MPFL in vivo. The subjects were comprised of ten male and ten female healthy volunteers. The length of the MPFL was measured using an open-MRI both from a leg extended position and a highly knee-flexed position in order to analyze the length change pattern of the MPFL. The MPFL length for men and women resulted in an average of 52 ± 3 mm and 43 ± 2 mm at the knee extended position, respectively. The length change pattern of the MPFL presented a slight change at up to a flexion angle of 60° and a decrease at over 60°. In terms of morphology, the fiber bundle of the MPFL experienced linear tension at a knee flexion angle of 60°. We determined that the MPFL length in vivo exhibited a specific length change pattern. MPFL mainly contributes to the medial constraint of a patella with a knee flexion of 0° to 60°, wherein it is expected to have the strongest strain at 60°. However, more studies are needed to obtain a better understanding of cases with a history of patellar dislocation.

Enhanced expression of interleukin-6, matrix metalloproteinase-13, and receptor activator of NF-kappaB ligand in cells derived from osteoarthritic subchondral bone.

BACKGROUND: The aim of this study was to clarify the significance of subchondral bone in the pathology of osteoarthritis (OA) by investigating the expression of inflammatory cytokines, proteases, and receptor activator of NF-kappaB ligand (RANKL)/receptor activator of NF-kappaB (RANK)/osteoprotegerin (OPG) involved in cartilage degeneration. METHODS: Subchondral bone was obtained from 19 patients diagnosed with knee OA and 4 patients diagnosed with femoral neck fracture. Subchondral bone osteoblasts (SBOs) were isolated, and total RNA was extracted. Messenger RNA expression of inflammatory cytokines, proteases, and RANKL/RANK/OPG were analyzed using a real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Real-time RT-PCR showed that mRNA expressions of interleukin-6 (IL-6), matrix metalloproteinase-13 (MMP-13), and RANKL were significantly enhanced in OA SBOs compared to SBOs without OA. The expressions of these genes was greater in patients with severe cartilage damage than in those with mild cartilage damage. A high correlation between mRNA expression of IL-6 and that of MMP-13 was found in OA SBOs. CONCLUSION: The increases in IL-6, MMP-13, and RANKL expression in OA SBOs suggest that in subchondral bone OA progression involves abnormal osseous tissue remodeling, which induces mechanical property changes. Cartilage degeneration in OA may also be due, at least in part, to IL-6 and MMP-13 produced by SBOs. Comprehensive research on these pathological features may lead to the development of more effective therapies for OA by administration of molecules that affect bone remodeling and metabolism.

Evaluation of the vascular status of autogenous hamstring tendon grafts after anterior cruciate ligament reconstruction in humans using magnetic resonance angiography.

The purpose of this study is to evaluate the vascular status of autogenous semitendinosus grafts after anterior cruciate ligament reconstruction in humans using magnetic resonance angiography. Twelve patients (mean age, 24.3 years) who underwent anterior cruciate ligament reconstruction with the 4-strand semitendinosus tendon were studied. All patients underwent contrast-enhanced magnetic resonance angiography and second-look arthroscopy in their reconstructed knees on an average of 15.8 months (range 9-22 months) after surgery. Blood vessels to the graft were visualised and contrast medium enhancement for visualising the femoral tunnel, graft, and tibial tunnel was evaluated. Magnetic resonance angiography showed that a branch of the middle genicular artery extended to the upper side of the graft through the posterior capsule and that branches of the inferior genicular artery ended at the lower side of the graft in all patients. These were consistent with the actual findings of the second-look arthroscopy. We found contrast medium enhancement in the femoral and tibial tunnels in all patients. The effect of enhancement at 9 months after ACL reconstruction was higher than that at 22 months. The graft showed enhancement patterns in the posterior portion of the femoral side and the anterior portion of the tibial side. This study demonstrated that the branches of the middle and inferior genicular arteries provide blood supply to the graft, which may influence the maturation of the graft. The revascularisation of the bone tunnels could play an important role in the healing of the ligament-bone tunnel junction.

Utility of delayed gadolinium-enhanced MRI (dGEMRIC) for qualitative evaluation of articular cartilage of patellofemoral joint.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was used for the measurement of relative proteoglycan depletion of articular cartilage in the patellofemoral (PF) joint following a proprietary protocol, which was compared with the X-ray images, proton density weighted MR images (PDWI) and arthroscopic findings. The study examined 30 knees. The ages ranged from 16 to 74 (average 40.3) years. The Gd-DTPA(2-)containing contrast medium was used in a single dose. The subjects were made to exercise the knee joint for 10 min; and MR images were taken 2 h after intravenous injection of contrast medium. T1-calculated images were produced and the region of interest (ROI) was set as follows. (1) ROI1: entire articular cartilage in a slice through the center of the patella. (2) ROI2: low signal region in T1-calculated images, which were set in a blind fashion by two observers. (3) ROI3: articular cartilage on one side that includes ROI2 where low signal region were detected (medial or lateral). ROI3 was set to examine the contrast of ROI2 with surrounding articular cartilage. The average T1 values of ROI1 was 393.5+/-33.6 ms for radiographic grade 0 and 361.3+/-11.1 ms for grade I, which showed a significant difference (P=0.036). The T1 value of ROI2 was 351.6+/-28.2 ms for grade I, 361.9+/-38.3 ms for grade II, 362.1+/-67.7 ms for grade III, and 297.8+/-54.1 ms for grade IV according to arthroscopic Outerbridge classification. All cases, that demonstrated decrease of T1 values on dGEMRIC (ROI2), showed abnormal arthroscopic or direct viewing findings. The ratio (ROI3/ROI2) in cases of only slight damage classified as Outerbridge grade I (6 cases) was an average of 1.04+/-0.02 and was 1.0 or greater in all cases, thereby indicating well-defined contrast with the surrounding cartilage. The diagnosis of damage in articular cartilage was possible in all 16 cases with radiographic K-L grade I on dGEMRIC, while the intensity changes were not found in 10 of 16 cases on PDWI. The dGEMRIC with a single-dose would be useful on a diagnosis of the area demonstrating early relative proteoglycan depletion in the articular cartilage of the PF joint prior to any discernible changes in the subchondral bone on X-ray images and exceeds to plain MR images for examining deterioration of articular cartilage.

Evaluation of collagen fiber maturation and ordering in regenerating tendons employing H-1 double quantum filtered NMR spectroscopy.

It is difficult to monitor the chronic stage of the healing process of ruptured tendons employing the present diagnostic modes. However, the results of this study have shown that 1H double quantum filtered (DQF) NMR spectroscopy is sensitive to the later stages of the healing process. Regenerated tendons of rabbits were dissected and measured at the end of the acute phase (three weeks), the subacute phase (nine weeks), and the chronic phase (13 and 18 weeks after tenotomy). Four parameters were determined by 1H DQF NMR spectroscopy: (a) the maximum signal intensity (h(max)) relative to the single quantum spectrum, (b) the creation time of the maximum signal intensity (tau(max)), (c) the decay time from the maximum signal intensity to a value half of that intensity (tau(1/2)) and (d) the residual dipolar splitting of water (delta), representing the order of the collagen fibers. The values of h(max), tau(max), tau(1/2), and delta of the intact Achilles tendons were 11.3+/-1.0%, 0.48+/-0.03 ms, 0.67+/-0.04 ms and 732+/-62 Hz (mean +/- SEM, n=6), respectively. In the regenerating tendon, h(max) increased from 0.41+/-0.12% at three weeks to 7.07+/-0.77% at 18 weeks, tau(max) decreased from 1.88+/-0.31 ms at three weeks to 0.72+/-0.04 ms at 18 weeks, tau(1/2) decreased from 11.6+/-1.8 ms at 3 weeks to 1.48+/-0.16 ms at 18 weeks, and delta increased from 129+/-8 Hz at three weeks to 414+/-29 Hz at 18 weeks. We have concluded that reordering of collagen fibers proceeds continuously even in the chronic stage of healing. Thus, the 1H DQF NMR spectroscopy is a useful non-invasive technique to evaluate the reconstruction and the order of collagen fibers in regenerating tendon. It is also suggested that tau(1/2) and h(max) are most useful for in vivo DQF NMR spectroscopy and imaging, respectively, in combination with tau(max).