Reliability and validity of pose estimation algorithm for measurement of knee range of motion after total knee arthroplasty.

We aimed to assess the reliability and validity of OpenPose, a posture estimation algorithm, for measurement of knee range of motion after total knee arthroplasty (TKA), in comparison to radiography and goniometry. In this prospective observational study, we analyzed 35 primary TKAs (24 patients) for knee osteoarthritis. We measured the knee angles in flexion and extension using OpenPose, radiography, and goniometry. We assessed the test-retest reliability of each method using intraclass correlation coefficient (1,1). We evaluated the ability to estimate other measurement values from the OpenPose value using linear regression analysis. We used intraclass correlation coefficients (2,1) and Bland-Altman analyses to evaluate the agreement and error between radiography and the other measurements. OpenPose had excellent test-retest reliability (intraclass correlation coefficient (1,1) = 1.000). The R2 of all regression models indicated large correlations (0.747 to 0.927). In the flexion position, the intraclass correlation coefficients (2,1) of OpenPose indicated excellent agreement (0.953) with radiography. In the extension position, the intraclass correlation coefficients (2,1) indicated good agreement of OpenPose and radiography (0.815) and moderate agreement of goniometry with radiography (0.593). OpenPose had no systematic error in the flexion position, and a 2.3° fixed error in the extension position, compared to radiography. OpenPose is a reliable and valid tool for measuring flexion and extension positions after TKA. It has better accuracy than goniometry, especially in the extension position. Accurate measurement values can be obtained with low error, high reproducibility, and no contact, independent of the examiner's skills.

Reliability and validity of OpenPose for measuring hip-knee-ankle angle in patients with knee osteoarthritis.

We aimed to assess the reliability and validity of OpenPose, a posture estimation algorithm, for measuring hip-knee-ankle (HKA) angle in patients with knee osteoarthritis, by comparing it with radiography. In this prospective study, we analysed 60 knees (30 patients) with knee osteoarthritis. We measured HKA angle using OpenPose and radiography before or after total knee arthroplasty and assessed the test-retest reliability of each method with intraclass correlation coefficient (1, 1). We evaluated the ability to estimate the radiographic measurement values from the OpenPose values using linear regression analysis and used intraclass correlation coefficients (2, 1) and Bland-Altman analyses to evaluate the agreement and error between OpenPose and radiographic measurements. OpenPose had excellent test-retest reliability (intraclass correlation coefficient (1, 1) = 1.000) and excellent agreement with radiography (intraclass correlation coefficient (2, 1) = 0.915), with regression analysis indicating a large correlation (R2 = 0.865). OpenPose also had a 1.1° fixed error and no systematic error when compared with radiography. This is the first study to validate the use of OpenPose for the estimation of HKA angle in patients with knee osteoarthritis. OpenPose is a reliable and valid tool for measuring HKA angle in patients with knee osteoarthritis. OpenPose, which enables non-invasive and simple measurements, may be a useful tool to assess changes in HKA angle and monitor the progression and post-operative course of knee osteoarthritis. Furthermore, this validated tool can be used not only in clinics and hospitals, but also at home and in training gyms; thus, its use could potentially be expanded to include self-assessment/monitoring.

Machine Learning Algorithm to Predict Worsening of Flexion Range of Motion After Total Knee Arthroplasty.

Background: Predicting the worsening of flexion range of motion (ROM) during the course post-total knee arthroplasty (TKA) is clinically meaningful. This study aimed to create a model that could predict the worsening of knee flexion ROM during the TKA course using a machine learning algorithm and to examine its accuracy and predictive variables. Methods: Altogether, 344 patients (508 knees) who underwent TKA were enrolled. Knee flexion ROM worsening was defined as ROM decrease of ≥10° between 1 month and 6 months post-TKA. A predictive model for worsening was investigated using 31 variables obtained retrospectively. 5 data sets were created using stratified 5-fold cross-validation. Total data (n = 508) were randomly divided into training (n = 407) and test (n = 101) data. On each data set, 5 machine learning algorithms (logistic regression, support vector machine, multilayer perceptron, decision tree, and random forest) were applied; the optimal algorithm was decided. Then, variables extracted using recursive feature elimination were combined; by combination, random forest models were created and compared. The accuracy rate and area under the curve were calculated. Finally, the importance of variables was calculated for the most accurate model. Results: The knees were classified into the worsening (n = 124) and nonworsening (n = 384) groups. The random forest model with 3 variables had the highest accuracy rate, 0.86 (area under the curve, 0.72). These variables (importance) were joint-line change (1.000), postoperative femoral-tibial angle (0.887), and hemoglobin A1c (0.468). Conclusions: The random forest model with the above variables is useful for predicting the worsening of knee flexion ROM during the course post-TKA.

Accuracy of different navigation systems for femoral and tibial implantation in total knee arthroplasty: a randomised comparative study.

PURPOSE: It remains to be established whether optical computed tomography (CT)-free and acceleration-based navigation systems differ in terms of implantation accuracy and clinical outcomes for total knee arthroplasty. This randomised prospective study compared the implantation accuracy of these two navigation systems in total knee arthroplasty. METHODS: Optical CT-free navigation (ExactechGPS) or acceleration-based navigation (KneeAlign2) was randomly assigned to the left or right knee of 45 patients who underwent a single-stage bilateral total knee arthroplasty: the ExactechGPS (n = 45) and KneeAlign2 groups (n = 45) were compared. Component alignments were evaluated using three-dimensional computed tomography and radiography at pre- and post-surgery. Implantation accuracy of the component alignment, proportion of outliers, postoperative range of motion, and Japanese Orthopaedic Association (JOA) score were compared between the systems. RESULTS: The implantation accuracies of the lower-extremity mechanical alignment, coronal femoral component angle, coronal tibial component angle, sagittal femoral component, axial femoral angle, and axial tibial angle had no significant difference between the groups. The implantation accuracy of the sagittal tibial component angle was superior in the ExactechGPS than the KneeAlign2 group (1.3° vs. 1.8°, P = 0.034). The proportions of outliers, range of motion, and JOA score had no significant difference between the groups. CONCLUSION: In the tibial sagittal plane, there was a significant difference in the implantation accuracy, but its difference did not affect the clinical outcomes. Both navigation systems have clinically acceptable implantation accuracy.

Gradual exacerbation of knee flexion angle after total knee arthroplasty in patients with diabetes mellitus.

OBJECTIVES: This study aimed to investigate the effect of diabetes mellitus (DM) on knee extension/flexion angle and its early clinical course after total knee arthroplasty (TKA). METHODS: Patients who received TKA were retrospectively divided into two groups based on haemoglobinA1c level; the DM group (23 knees) and the control group (23 knees matched for baseline characteristics). The passive knee extension/flexion angle, gait speed and Japanese Orthopaedic Association (JOA) score were evaluated preoperatively and at 1, 6 and 12 months postoperatively. RESULTS: There was no significant difference in the passive knee flexion angle at 1 and 6 months postoperatively between the groups (p = .302, p = .160, respectively). The passive knee flexion angle was significantly lower at 12 months postoperatively in the DM group than the control group (p = .014). In the DM group, the passive knee flexion angle at 6 and 12 months significantly decreased compared with that at 1 month postoperatively (p = .021, p < .001, respectively). There were no significant differences in the knee extension angle, gait speed and JOA score between the groups. CONCLUSION: Patients with DM are likely to experience passive knee flexion angle exacerbating from 1 to 6 months after TKA.

IgA Vasculitis Developed as an Adverse Effect of Tofacitinib Taken for Rheumatoid Arthritis.

Tofacitinib is a new small-molecule inhibitor of the JAK/STAT signaling pathway used to treat rheumatoid arthritis. We herein report a case of IgA vasculitis apparently caused by tofacitinib. A 67-year-old woman with rheumatoid arthritis developed IgA vasculitis after taking tofacitinib for 6 months. She presented with proteinuria and purpura of the lower extremities. Biopsy specimens from her skin and kidney were compatible with IgA vasculitis. Following termination of tofacitinib, the patient completely recovered from the IgA vasculitis. Drug-induced IgA vasculitis has been previously described for anti-tumor necrosis factor-(TNF)α therapies, but this is the first report of this adverse effect with anti-JAK therapy.

The accuracy of the "projected surgical transepicondylar axis" relative to the "true surgical transepicondylar axis" in total knee arthroplasty.

BACKGROUND: In TKA, we have used the "projected SEA", which is obtained by projecting the "true SEA" on the distal femoral cutting plane in clinical practice to determine the femoral component rotation. There are no reports examining the accuracy of the "projected SEA". In this study, we investigated the difference between the "true SEA" and "projected SEA". METHODS: The present study was a CT-based computer-simulated case series. We evaluated 34 knees without osteoarthritis changes. These patients were selected from the operative schedule prior to THA. We defined the "true SEA" on the 3D model and the "projected SEA" on the cutting plane parallel to the distal femoral axis obtained based on the "true SEA". We changed the cutting angles from 20° flexion to 20° extension, and from five degrees varus to five degrees valgus. We measured the "true SEA angle" and "projected SEA angle" regarding the posterior condylar axis (PCA). RESULTS: The mean "true SEA angle" was 3.04°±1.34° (0.6-5.0°). The mean "projected SEA angle" was 3.43°±1.58° at 20° flexion, 3.42°±1.56° at 0° flexion, 3.43°±1.52° at 20° extension, 3.39°±1.59° at five degrees valgus, and 3.39°±1.50° at five degrees varus. At each cutting angle, the "projected SEA angle" was significantly larger than the "true SEA angle" (p<0.001). There was no significant difference between any of the "projected SEA angles" (p>0.001). CONCLUSIONS: We found that the true SEA and projected SEA do not differ significantly (0.39°±0.29° [range 0-1.0°]).

A Case Report of Isolated Cuboid Nutcracker Fracture.

Isolated cuboid fractures are very rare, since they typically occur in combination with midfoot fractures or dislocations. A 61-year-old man presented at our hospital with pain and swelling on the outside of his right foot. The lateral column of his right foot was shortened by approximately 6.5 mm on X-ray. CT showed displacement of the joint surface between the cuboid and the fourth metatarsal, with a 3.5 mm depression. An MRI revealed no other injuries. Based on these findings, we diagnosed the patient with an isolated nutcracker fracture of the cuboid. Using a 1.9 mm arthroscope, we examined the Lisfranc joint. Then the depressed fragments were elevated until the regular joint line was restored. A bone biopsy needle was then used to fill in the large defect with artificial bone. In this case, we did not plate the fracture. Six months after surgery, patient could walk without pain. We report a very rare case of isolated nutcracker fracture of the cuboid. In addition, we suggest our new treatment plan of this fracture.

Irreducible plantar dislocation of the interphalangeal joint of the great toe due to an accessory sesamoid bone: a case report.

INTRODUCTION: Great toe dislocation frequently occurs at the metatarsophalangeal joint. However, an irreducible dislocation of the great toe interphalangeal (IP) joint due to an accessory sesamoid bone is relatively unusual. CASE REPORT: A 23-year-old woman suffered a dislocated IP joint of the left great toe. The distal phalanx was plantar subluxated, and the articular surface was misaligned. Ultrasound, magnetic resonance imaging, and computed tomography images did not indicate any factors inhibiting reduction. In addition, the sesamoid bone at the IP joint was found to be rotated in the long-axis direction. The sesamoid bone of the IP joint was hooked from the distal direction and occupied the intercondylar area. IP joint of the left great toe was flexed and the distal phalanx was pushed toward the proximal phalanx during reduction locking with fluoroscopic guidance under local anesthesia, and the dislocation was successfully reduced. DISCUSSION: The sesamoid bone at the IP joint is anatomically located dorsal to the flexor hallucis longus tendon and volar plate. The sesamoid bone fitted exactly in the distal intercondylar area. The sesamoid bone in our patient could be rotated by forcible plantar flexion of the IP joint displaced proximally and hooked into the intercondylar area from the proximal aspect. Then, the distal phalanx was pulled proximally through the volar plate. This is the first report on a plantar dislocation of the IP joint.

Longterm Safety and Efficacy of Subcutaneous Tocilizumab Monotherapy: Results from the 2-year Open-label Extension of the MUSASHI Study.

OBJECTIVE: To evaluate the longterm safety and efficacy of subcutaneous tocilizumab (TCZ-SC) as monotherapy in patients with rheumatoid arthritis (RA). METHODS: Of 346 patients who received 24 weeks of double-blind treatment with either TCZ-SC monotherapy, 162 mg every 2 weeks (q2w); or intravenous TCZ (TCZ-IV) monotherapy, 8 mg/kg every 4 weeks; 319 patients continued to receive TCZ-SC q2w in the 84-week open-label extension (OLE) of the MUSASHI study (JAPICCTI-101117). Efficacy, safety, and immunogenicity were evaluated for all patients treated with TCZ during 108 weeks. RESULTS: The proportions of patients who achieved American College of Rheumatology 20/50/70 responses, low disease activity [28-joint Disease Activity Score (DAS28) ≤ 3.2], or remission (DAS28 < 2.6) at Week 24 were maintained until Week 108. The incidences of adverse events and serious adverse events were 498.3 and 16.9 per 100 patient-years (PY), respectively. The overall safety of TCZ-SC monotherapy was similar to that of TCZ-IV monotherapy. Rates of injection site reactions (ISR) through 108 weeks remained similar to rates through 24 weeks. ISR were mild and did not cause any patient withdrawals. No serious hypersensitivity events (including anaphylactic reactions) occurred. Anti-TCZ antibodies were present in 2.1% of patients treated with TCZ-SC monotherapy. CONCLUSION: TCZ-SC monotherapy maintained a favorable safety profile and consistent efficacy throughout the 108-week study. Like TCZ-IV, TCZ-SC could provide an additional treatment option for patients with RA.

Transverse incision advantages for total knee arthroplasty.

BACKGROUND: If a transverse incision can be safely used for total knee arthroplasty (TKA), decreases in scar formation, reduced injury of the infrapatellar branch of the saphenous nerve and improved kneeling motion will be observed. METHODS: We evaluated 95 patients (101 knees) on whom primary TKA was performed with follow-up of more than 2 years. A longitudinal incision was used for the first 40 knees and a transverse incision for the remaining 61 knees. Operation time, blood loss, complications and Knee Society Score were evaluated. Wound lengths, widths and the Manchester Scar Scale (MSS) were measured 1 year after the surgery. Further examination evaluated sensory disturbances and whether kneeling was possible. RESULTS: The complication rate in both groups was almost the same. The wound lengths measured at a 90° knee-flexed position were about 15 cm with no significant difference between the groups. The average width measured at a maximum area was significantly smaller in the transverse group than in the longitudinal group. MSS of the transverse group was also significantly lower than that of the longitudinal group. Sensory disturbance was found to be significantly smaller in the transverse group than in the longitudinal group both in subjective and objective evaluation at 1 year after surgery. When a transverse incision was used, the direction of the incision corresponded to the running direction of the saphenous nerve, and thus, we were able to reduce sensory disturbances on the distal lateral side of the knee joint. The transverse group (70.4%) performed significantly better than the longitudinal group (40.6%) at kneeling motion. CONCLUSIONS: We showed that making a transverse incision is a safe method, resulting in a reduction of scar formation and less dysfunction of the infrapatellar branch of the saphenous nerve, and improvement of kneeling motion.

Bilateral total knee arthroplasty after spontaneous osseous ankylosis in rheumatoid arthritis.

Total knee arthroplasty (TKA) was carried out on both knee joints for spontaneous bony ankylosis due to rheumatoid arthritis (RA). Preoperative fixation angles were 40 degrees . First, the peroneal nerve was released prior to TKA. Quadriceps snip was performed to evert the patella laterally. Bilateral TKAs were carried out using a stabilized prosthesis. The results showed full extension to 70 degrees flexion at 3 years after the surgery. Absence of pain, maintenance of stability, and walking ability were achieved, without any significant complication. Total knee arthroplasty following takedown of a spontaneous ankylosed knee is an effective procedure under appropriate knee conditions.