Total talar replacement has been reported to have favorable short-term and intermediate-term results for the treatment of osteonecrosis of the talus. The purpose of this study was to evaluate the ...long-term clinical results of total talar replacement for a minimum of 10 years after the surgical procedure.
From October 2005 to April 2011, 19 ankles in 18 patients (1 male and 17 female) were treated using a total talar prosthesis for osteonecrosis of the talus. The median follow-up period was 152 months (interquartile range IQR, 138, 160 months). The Ankle Osteoarthritis Scale (AOS) score, the Japanese Society for Surgery of the Foot (JSSF) Ankle-Hindfoot Scale score, and the presence of osteophytes and degenerative changes in the adjacent joints were assessed preoperatively and at the final follow-up. Subsidence of the prosthesis was also assessed at the earliest opportunity for full weight-bearing and the final follow-up. The postoperative range of motion of the ankle was assessed at the final follow-up.
The median scores for all subscales of the AOS significantly improved. The median JSSF Ankle-Hindfoot Scale score significantly improved from 58 (IQR, 55, 59.5) to 97 (IQR, 87, 99.5). In the subcategories of this scale, the median pain score improved from 20 (IQR, 20, 20) to 40 (IQR, 30, 40), and the median function score improved from 28 (IQR, 26, 30.5) to 47 (IQR, 47, 50). The median postoperative range of motion of the ankle was 45° (IQR, 42.5°, 55°). Subsidence of the implant was not recognized at the final follow-up (p = 0.083). Proliferation of osteophytes and degenerative changes in the adjacent joints did not affect the overall results.
The customized alumina ceramic total talar prosthesis produced stable clinical outcomes over 10 years, and the patients treated with total talar replacement showed favorable clinical results over this time frame.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Treatment of osteonecrosis of the talus is challenging. Total talar replacement has the potential to restore the function of the ankle joint without an associated leg-length discrepancy. The purpose ...of the present study was to investigate postoperative function and pain after total talar replacement in patients with osteonecrosis of the talus.
Fifty-five ankles in fifty-one consecutive patients with osteonecrosis of the talus who were treated with a total talar replacement from 2005 to 2012 were included in the investigation. Scores according to the Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale and the Ankle Osteoarthritis Scale (AOS) were assessed before surgery and at the final follow-up evaluation.
According to the JSSF ankle-hindfoot scale, the score for pain improved from a mean (and standard deviation) of 15 ± 9.4 points (range, 0 to 20 points) to 34 ± 5.6 points (range, 20 to 40 points); the score for function, from 21.2 ± 9.7 points (range, 4 to 38 points) to 45.1 ± 4.0 points (range, 37 to 50 points); the score for alignment, from 6.0 ± 2.8 points (range, 5 to 10 points) to 9.8 ± 0.9 points (range, 5 to 10 points); and the total score, from 43.1 ± 17.0 points (range, 11 to 68 points) to 89.4 ± 8.4 points (range, 76 to 100 points). According to the AOS scale, the score for "pain at its worst" improved from a mean of 6.1 ± 3.3 points (range, 0 to 9.9 points) to 2.0 ± 1.7 points (range, 0 to 6.3 points).
Prosthetic talar replacement is a useful procedure for patients with osteonecrosis of the talus as it maintains ankle function.
This study extends the particle swarm optimization (PSO)-based bifurcation points derivation method to the autonomous systems. PSO avoids the need to carefully set the initial parameters of the ...dynamical system or to differentiate the objective function. In addition, it can derive the bifurcation points quickly and accurately, and its efficacy has previously been demonstrated for discrete dynamical systems and non-autonomous systems but not for autonomous systems. This paper proposes an extended PSO-based method for autonomous systems by incorporating the computation of a Poincaré map and a bisection method in the algorithm. To validate the effectiveness of the proposed method, it was applied to deriving the local bifurcation points of a three-dimensional autonomous system to confirm and demonstrate its effectiveness.
Abstract
Background
Varus ankle osteoarthritis is classified using only weightbearing anteroposterior ankle radiographs; however, sagittal ankle alignment may also affect the position and extent of ...joint space obliteration. We hypothesized that the sagittal alignment of the ankle may also affect the position and extent of joint space obliteration visible on the coronal section; therefore, we identified the sites of joint space obliteration in patients with stage 3 varus ankle osteoarthritis for comparison with the sites observed on simulated weightbearing computed tomography and investigated the effects of anterior and posterior ankle subluxation.
Methods
Simulated weightbearing computed tomography scans of 83 ft with varus ankle osteoarthritis (26 stage 3a, 57 stage 3b) were performed to check for joint space obliteration in the ankle. Further classification as exhibiting either anterior, posterior, or no subluxation on weightbearing lateral radiographs was performed.
Results
Anterior, posterior, and no subluxation was seen in 5, 9, and 12 ankles among the 26 classified as stage 3a, respectively, and in 22, 12, and 23 ankles among the 57 classified as stage 3b, respectively. The mean tibial lateral surface angle on weightbearing lateral radiographs in stage 3a ankles was 75.6, 83.3, and 80.3 degrees in the anterior, posterior, and no subluxation groups, respectively; and 75.5, 86.6, and 82.7 degrees in stage 3b ankles (
p < .05
). In stage 3b ankles, widespread joint space obliteration was observed at the anterior distal articular surface of the tibia in all 22 ankles with anterior subluxation and at the posterior distal articular surface of the tibia in all 12 ankles with posterior subluxation.
Conclusions
Simulated weightbearing computed tomography revealed joint space obliteration at the anterior distal articular surface of the tibia in stage 3b ankles with anterior subluxation and at the posterior side in stage 3a and 3b ankles with posterior subluxation. In some patients with stage 3 varus ankle osteoarthritis, the obliteration of the joint space is difficult to evaluate accurately using only weightbearing anteroposterior radiographs; weightbearing lateral radiographs should also be performed.
This study extends the particle swarm optimization (PSO)-based bifurcation points derivation method to the autonomous systems. PSO avoids the need to carefully set the initial parameters of the ...dynamical system or to differentiate the objective function. In addition, it can derive the bifurcation points quickly and accurately, and its efficacy has previously been demonstrated for discrete dynamical systems and non-autonomous systems but not for autonomous systems. This paper proposes an extended PSO-based method for autonomous systems by incorporating the computation of a Poincaré map and a bisection method in the algorithm. To validate the effectiveness of the proposed method, it was applied to deriving the local bifurcation points of a three-dimensional autonomous system to confirm and demonstrate its effectiveness.
Purpose
Flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendons are frequently used in surgery. Therefore, it is necessary to evaluate the chiasma plantare formation preoperatively. ...The development of ultrasonography (US) may help the chiasma plantare formation evaluation. The purpose of this study is to prove the usefulness of the US method using cadavers.
Methods
Eleven cases (twenty-two ankles) were obtained from Asian adult cadavers. At first, we evaluated and compared the chiasma plantare formation using US. Later, we evaluated that using the findings after dissection as type A (connection from FHL to FDL of the second toe), type B (connection from FHL to the second and third toes), type C (connection from FHL to the second through fourth toes), or type D (connection from FHL to all lesser toes).
Results
Chiasma plantare formation was classified as types A and B in fifteen and seven ankles, respectively. After dissection, chiasma plantare formation was classified as types A, B, and C in fourteen, six, and two ankles, respectively. Therefore, there was an 86% similarity between the two methods.
Conclusions
Chiasma plantare formation can be reliably and noninvasively evaluated using US. This may be useful for preoperative rehabilitation or surgical procedure planning.
In this study, we investigated the human capacity to generate randomness in decision-making processes using the rock-paper-scissors (RPS) game. The randomness of the time series was evaluated using ...the time-series data of RPS moves made by 500 subjects who played 50 consecutive RPS games. The indices used for evaluation were the Lempel–Ziv complexity and a determinism index obtained from a recurrence plot, and these indicators represent the complexity and determinism of the time series, respectively. The acquired human RPS time-series data were compared to a pseudorandom RPS sequence generated by the Mersenne Twister and the RPS time series generated by the RPS game’s strategy learned using the human RPS time series acquired via genetic programming. The results exhibited clear differences in randomness among the pseudorandom number series, the human-generated series, and the AI-generated series.
Impingement between the Achilles tendon and the posterosuperior prominence of the calcaneus is considered to be a cause of insertional Achilles tendinopathy. The corresponding treatment intends to ...reduce tensile stress from calf muscles and avoid hyper-dorsiflexion of the ankle joint for decreasing the contact pressure; however, no study has reported on whether these treatments can decrease impingement. Thus, this study investigated the hypothesis that the tensile stress of the Achilles tendon and ankle motion affect the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus. Six fresh-frozen cadaveric lower leg specimens were procured. Each specimen was set to a custom foot-loading frame and loaded with a ground reaction force of 40 N and a tensile load of 70 N along the Achilles tendon. The contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus was measured using a miniature pressure sensor under different tensile loadings of the Achilles tendon at the neutral ankle position. Similarly, the contact pressures during the ankle motion from a neutral position to maximum dorsiflexion were measured. The tensile load of the Achilles tendon and ankle motion affected the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus. The contact pressure increased with tensile load or ankle dorsiflexion. Conditions with increasing the tensile load of the Achilles tendon or under ankle dorsiflexion increase the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus.
Background:
The impact of varus ankle osteoarthritis (OA) on the distal tibial fibular syndesmosis is poorly described. This study aimed to investigate the possible relationship between the condition ...of the distal tibial fibular syndesmosis and the degree of the varus deformity using weightbearing simulated computed tomography (CT), in patients with varus ankle OA.
Methods:
This retrospective comparative study included 155 varus ankles, divided into 4 Takakura-Tanaka groups (stage 2, 3a, 3b, and 4). A control group comprised 35 ankles without prior ankle disorders. The angles between the tibial shaft and the articular surface of the tibial plafond on the anteroposterior view (TAS), and articular surfaces of the tibial plafond and talar dome (TTW) were measured from weightbearing ankle radiographs. The varus angle of the ankle (VA) was defined as 90 – TAS + TTW. On the CT axial view, 1 cm proximal to the tibial plafond, the area of the syndesmosis (“CT-area”) and the distance between the fibula and the tibia (CT-FCS) were measured.
Results:
The CT area in stages 2, 3a, 3b, 4, and control group were 99, 79, 77, 103, and 97 mm2, respectively. The CT-FCS were 3.5, 3.1, 2.9, 4.3, and 3.9 mm, respectively. In all 155 OA ankles, CT area and CT-FCS were negatively correlated with the VA (correlation coefficient r = –0.38, P < .01; and r = 0.38, P < .01, respectively). Both CT area and CT-FCS were significantly smaller in stages 3a and 3b than in the control group (P < .01).
Conclusion:
There may be a relationship between the narrowing of the syndesmosis and the varus deformity in patients with varus ankle OA, especially in stages 3a and 3b.
Clinical Relevance:
Clinicians should be aware of the impact of varus ankle arthritis on the distal tibial fibular syndesmosis when operatively treating varus ankle OA. For some patients, the isolated treatment for the tibiotalar joint may be insufficient, and treatment for the syndesmosis as well as tibiotalar joint may be needed.
Level of Evidence:
Level III, retrospective case control study.
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