Aims

Total ankle arthroplasty (TAA) has become the most reliable surgical solution for patients with end-stage arthritis of the ankle. Aseptic loosening of the talar component is the most common complication. A custom-made artificial talus can be used as the talar component in a combined TAA for patients with poor bone stock of the talus. The purpose of this study was to investigate the functional and clinical outcomes of combined TAA.

The purpose of this study was to evaluate the clinical results of a newly designed prosthesis to replace the body of the talus in patients with aseptic necrosis. Between 1999 and 2006, 22 tali in 22 patients were replaced with a ceramic prosthesis. A total of eight patients were treated with the first-generation prosthesis, incorporating a peg to fix into the retained neck and head of the talus, and the remaining 14 were treated with the second-generation prosthesis, which does not have the peg. The clinical results were assessed by the American Orthopaedic Foot and Ankle Society ankle/hindfoot scale.

The mean follow-up was 98 months (18 to 174). The clinical results of the first-generation prostheses were excellent in three patients, good in one, fair in three and poor in one. There were, however, radiological signs of loosening, prompting a change in design. The clinical results of the second-generation prostheses were excellent in three patients, good in five, fair in four and poor in two, with more favourable radiological appearances. Revision was required using a total talar implant in four patients, two in each group.

Although the second-generation prosthesis produced better results, we cannot recommend the use of a talar body prosthesis. We now recommend the use of a total talar implant in these patients.

Introduction and aims

Recently many implants for ankle arthroplasty have been developed around the world, and especially some mobile bearing, three-component implants have good results. Nevertheless, at our institution fixed two-component, semi-constrained alumina ceramic total ankle arthroplasty (TAA) with TNK Ankle had been performed since 1991 and led to improved outcomes. We report clinical results and in vivo kinematic analyses for TNK Ankle.

We have performed two-component total ankle arthroplasty (TNK ankle) since 1991 and reported good clinical results. However, in vivo kinematics of this implant are not well understood. The purpose of this study was to measure three-dimensional kinematics of total ankle arthroplasty during non-weightbearing and weightbearing activities.

Forty-seven patients with a mean age of 71 years were enrolled. Preoperative diagnosis was osteoarthritis in 36 patients and rheumatoid arthritis in 11 patients, and the mean followup was 50 months. Radiographs were taken during nonweightbearing maximal dorsiflexion and plantarflexion, and weightbearing maximal dorsiflexion and plantarflexion. Three-dimensional kinematics were determined using 3D-2D model registration techniques. Anatomic coordinate systems were embedded in the tibial and talar implant models, and they were projected onto the radiographic image. Three-dimensional positions and orientations of the implants were determined by matching the silhouette of the models with the silhouette of the image.

From non-weightbearing dorsiflexion to plantarflexion, the talar implant showed 18.1, 0.3, and 1.2 degrees of plantarflexion, inversion, and internal rotation respectively. It also translated 0.8mm posteriorly. There was not significant difference between non-weightbearing and weightbearing kinematics except for the plantarflexion angle (p = 0.007). Posterior hinging, in which tibiotalar contact was seen at only the posterior edge of the talar implant, was observed in 16 patients at either non-weightbearing or weightbearing plantarflexion. There was significantly larger plantarflexion in patients with posterior hinging than patients without hinging (p < 0.001). Nine patients showed anterior hinging at maximum dorsiflexion, and 11 patients showed talar lift-off at maximum plantarflexion.

More than half of the patients showed anterior or posterior edge contact, which might cause excessive contact stress and lead to implant failure in the longer term. This phenomenon is due to the difference in rotation axis between the natural ankle and the implant ankle arthroplasty.

The results of total ankle arthroplasty using metal (first generation) and ceramic (second) prostheses were not good for loosening sinking. Then, we have replaced on 159 ankles in 146 cases using beads-formed alumina ceramic prostheses (third) from 1991 to 2006. The follow-up periods were ranged from 2 to 17 years (average 6.5 years). Revision was performed for 13 cases (arthrodesis, 3; re-replacement by artificial talus. 10). Overall satisfactory result of new prostheses for OA was 88%, RA was 74%. Results of OA were better than RA. Furthermore, we have re-replaced using ceramic talar whole body for 10 revision cases. These results until present have been good. It is convinced that total arthroplasty with talar whole body can be indicated for cases with severe deformity and revision.

The material properties of gamma irradiated Ultra High Molecular Weight (UHMW) polyethylene are known to degrade during exposure to air. Though gamma inert-sterilization has been developed to decrease free radicals, the rate of degeneration of UHMW polyethylene in vivo has not well known. This study aimed to compare the properties of gamma inert-irradiated highly-cross-linked UHMW polyethylene samples after exposure to air and the properties of gamma inert-irradiated highly-crosslinked UHMW polyethylene samples after exposure to liquid.

UHMW polyethylene samples were machined from heat-compressed sheet made of medical grade GUR 1050 (Ticona, Kelsterbach, Germany). Samples were rectangular, where the dimensions were 50mm in length, 5 mm in width and 2 mm in thickness. Samples were divided into four groups of 0, 60, 100 and 200 kGy irradiation in N2 gas. These samples were then exposed to air or Ringer’s solution for half a year. Dynamic vis-coelastic measurements and, Fourier Transform Infrared Spectrometry (FTIR) and Electron Spin Resonance (ESR) analyses were performed on samples immediately after inert-irradiation, after half-year-exposure to 25°C air (Air-exposure) and after half-year-exposure to 37°C Ringer’s solution (Liquid-exposure). Dynamic viscoelastic measurements were conducted over a temperature range of −150 to 350°C using a Dynamic Mechanical Spectrometer (Seiko Instruments, Osaka, Japan). FTIR analysis was conducted using a Perkin-Elmer Spectra BX (Norwalk, CT) with 100-μm thick slices. ESR analysis was also conducted using a JES-TE200 (Nippon-Denshi, Akishima, Japan).

Although the dynamic viscoelastic performance of 0 kGy irradiated storage sample was not different from that of original sample, the loss tangent value (tanδ, E”/E’) of 60, 100 and 200 kGy irradiated storage samples was different from that of original samples (Fig. 1). The difference of Liquid-exposure was larger than that of Air-exposure. Although a FTIR peak at 1718 cm-1 wave numbers was not observed in 0 kGy irradiated storage sample, obvious peak was observed in 100 and 200 kGy irradiated storage samples (Fig. 2). The peak of Liquid-exposure was larger than that of Air-exposure. The ESR analysis showed free radicals in storage samples.

The dynamic viscoelastic performance of 60, 100, 200 kGy irradiated storage sample was different from that of original sample, whereas the performance of 0 kGy irradiated storage sample was not different from that of original sample. The difference of Liquid-exposure was larger than that of Air-exposure. The storage modulus value of 60, 100, 200 kGy irradiated Liquid-exposure decreased and the reason for this was thought to be chain scission by oxidation for half-year exposure to Ringer’s solution. Obvious FTIR peak at 1718 cm-1 wave numbers was observed in 100 and 200 kGy irradiated storage samples. The peak of Liquid-exposure was larger than that of Air-exposure. This indicated that the oxidation of Liquid-exposure quickly progressed during half-year storage and the reason for this was thought to be chain scission by high liquid temperature. The results of the present study suggested that the properties of gamma irradiated UHMW polyethylene quickly degraded in vivo.

In this retrospective study we have assessed the results of low tibial valgus osteotomy for varus-type osteoarthritis of the ankle and its indications.

We performed an opening wedge osteotomy in 25 women (26 ankles). The mean follow-up was for eight years and three months (2 years 3 months to 17 years 11 months).

Of the 26 ankles, 19 showed excellent or good clinical results. Their mean scores for pain, walking, and activities of daily living were significantly improved but there was no change in the range of movement. In the ankles which were classified radiologically as stage 2 according to our own grading system, with narrowing of the medial joint space, and in 11 as stage 3a, with obliteration of the joint space at the medial malleolus only, the joint space recovered. In contrast, such recovery was seen in only two of 12 ankles classified as stage 3b, with obliteration of the joint space advancing to the upper surface of the dome of the talus. Low tibial osteotomy is indicated for varus-type osteoarthritis of stage 2 or stage 3a.

To investigate the limitation of proximal spherical metatarsal osteotomies for feet with severe hallux valgus, a follow-up study was performed on the patients whose preoperative hallux valgus angles were 40 degrees or more.

Forty-eight feet in 37 patients (11 male, 37 female, 60 years range 20 to 84 years) were investigated. Mean follow-up was 4 years and 1 month ranging from two to eight years. The spherical osteotomy, performed using a curved chisel, was devised for correcting not only varus deviation of the first metatarsal but also pronation and dorsiflexion. A distal soft tissue procedure was done at the same time. Twenty feet received combined operations for their combined deformities.

Eighty-one percent of the patients were satisfied with the results. However, six of twelve patients whose preoperative hallux valgus angles were 50 degrees or more were unsatisfactory. Mild metatarsalgia remained in eight feet at the follow-up, but no new metatarsalgia developed in any patients. The mean value of the hallux valgus angle improved from 46.6 degrees to 11.1 degrees. The patients whose preoperative hallux valgus angle were 50 degrees or more showed 16.4 degrees of average hallux valgus angle at follow-up. Their results varied widely and most of them had inadequate correction. The mean correction toward plantar flexion was 0.7 degrees. Average shortening of the first metatarsal was 3.4mm. The shortening of the first metatarsal had not caused worsening of metatarsalgia if adequate correction of hallux valgus was achieved and malunion toward dorsi-flexion was prevented.

The proximal spherical osteotomy could consistently achieve satisfactory results for the patients whose hallux valgus angles are under 50 degrees. However, the results were worse in feet with more severe deformities. Other procedures for hallux valgus or proper combined operations were necessary for such patients.

We have treated osteochondral lesions of the talus using cortical bone pegs. We examined 27 ankles (27 patients) after a mean follow-up of 7.0 years (2 to 18.8). The mean age of the patients was 27.8 years (12 to 62). An unstable osteochondral fragment or osteosclerotic changes in the bed of the talus were regarded as indications for the procedure.

The clinical results were good in 24 ankles (89%) and fair in three (11%); none had a poor result. There was also radiological improvement in 24 ankles. Repair of the articular surface and stability of the lesion can be achieved even in unstable chronic lesions.

We studied the development of ball-and-socket deformity of the ankle by arthrography and radiography in 14 ankles of ten patients with congenital longitudinal deficiency of the fibula accompanied by various anomalies. The mean follow-up was for 18 years 10 months.

In three ankles in infants less than one year old the lateral and medial sides of the ankle were already slightly round. In another seven ankles the ball-and-socket appearance developed before the age of five years. This was thought to be due to osseous coalition which limits eversion and inversion. In another four ankles in children who were over the age of one year at the initial examination, the deformity was demonstrated by arthrography and radiography at their first examination.

Ball-and-socket deformity accompanied by tarsal coalition is an acquired deformity secondary to limitation of movement of the subtalar and midtarsal joints. It has completely developed by about five years of age.

We treated 43 acute tears of the calcaneofibular ligament by operation in 43 patients after subtalar arthrography. There were 22 men and 21 women with a mean age of 22.3 years (14 to 61). Anteroposterior (AP), lateral and oblique views were obtained with the foot in 45° of internal rotation and the ankle in the neutral position. Any communication or leakage to the ankle, tendon sheaths, subcutaneous tissue and sinus tarsi was recorded. We examined an oblique view of the microrecess along the interosseous ligament and an AP view of the lateral recess just under the distal end of the fibula. We also studied a control group of 27 patients with isolated injuries of the anterior talofibular ligament without rupture of the calcaneofibular ligament.

The findings in the two groups were significantly different when examined for leakage to the ankle (p = 0.0002), to the peroneal tendon sheaths (p = 0.0347) and to the subcutaneous tissue (p = 0.0222), absence of the microrecess (p = 0.0055) and presence of the lateral recess (p = 0.0012).

Many ankle sprains which involve tearing of the calcaneofibular ligament are accompanied by injuries of the subtalar joint. Combined injuries of the anterior talofibular ligament and calcaneofibular ligament, and isolated injury of the anterior talofibular ligament should be differentiated.

We examined seven patients with tarsal tunnel syndrome in one foot caused by talocalcaneal coalition and a ganglion. We excised the coalition and the ganglion in six of them. All the patients had pain, sensory disturbance in the sole, and a positive Tinel’s sign. Older patients with a long history showed atrophy and weakness of the plantar muscles.

Talocalcaneal coalition can be diagnosed on a plain lateral radiograph and an anteroposterior radiograph externally rotated 20°, and confirmed by CT. MRI is also useful for diagnosis. The coalitions were medial, and the ganglion had developed from the incomplete part of the coalition; it was multilocular in some patients.

After resection, there was early pain relief but sensory disturbances and Tinel’s sign persisted. The postoperative results were excellent in one patient, good in four and fair in one.

We lengthened seven first metatarsals in four patients with short great toes by callus distraction using an external fixator. Good clinical and cosmetic results were obtained. Bone lengthening is effective in patients with short great toes not only for cosmesis, but also to relieve pain and callosities on the plantar aspect of the second and third metatarsal heads.

Excessive lengthening of the first metatarsal resulted in limitation of the range of movement of the metatarsophalangeal joint of the great toe. To prevent this the amount of lengthening should not exceed 40% of the preoperative length of the metatarsal.

Primary osteoarthritis of the ankle with no history of trauma is rare. We report the use of a low tibial osteotomy on 18 ankles in 18 patients, two men and 16 women. The osteotomy is designed to correct the varus tilt and anterior opening of the distal tibial joint surface where it has been shown by weight-bearing radiographs and arthroscopy that there is healthy articular cartilage on the lateral side of the ankle. An opening-wedge osteotomy was used to achieve slight overcorrection. Follow-up of the 18 ankles at an average of 6 years 11 months (2.7 to 12.10) showed the results by our own scoring system to be excellent in six ankles, good in nine, and fair in three with no poor results. Of the three patients with fair results, two had been undercorrected and the third had little residual articular cartilage. Arthroscopic examination of ten ankles showed repair by fibrocartilage in seven. We conclude that slight overcorrection of deformity by low tibial osteotomy is effective in treating intermediate-stage primary osteoarthritis of the ankle.

From 1975 to 1988, operative treatment was performed on 50 feet in 45 patients with tarsal tunnel syndrome. The causes of this syndrome were correlated with operative findings and included ganglia in 18, and a bony prominence from talocalcaneal coalition in 15. Five feet had sustained an injury, tumours were found in three and there was no obvious cause in nine. In most cases in need of operative treatment, there was a space-occupying lesion. Classifying the results according to causes, those with coalition or a tumour fared better, and idiopathic and traumatic cases had a worse outcome. In cases with a definite lesion, an excellent result can be expected from surgical treatment carried out soon after onset of the condition.

Ball-and-socket ankle is a rare deformity associated with such pre-existing conditions as congenital shortening of the lower limb, coalition of tarsal bones, absent digital rays and aplasia or hypoplasia of the fibula. We have observed seven patients with this deformity for an average of six years from initial examination at 20 days to 3.5 years. Arthrography showed that the configuration of the ankle was apparently normal in patients under 10 months of age and that a ball-and-socket joint develops by four to five years of age, possibly in compensation for the loss of inversion and eversion caused by tarsal coalition. Ball-and-socket joint is therefore probably not congenital, but is an acquired deformity secondary to various pre-existing congenital conditions.