The Mobility (DePuy International) is a three-component, cobalt chrome, uncemented design.

Methods

There were 106 men and 94 women (mean age 65 years; 22 - 85). 69 patients had inflammatory arthritis and 131 osteo-arthritis. 27 patients (13 B-P, 14 STAR) had a pre-operative varus/valgus deformity greater than or equal to 20 degrees. Mean follow-up was 48 months (36-72).

Twenty-four replacements were performed in 19 patients (13 female: 6 male), with average age of 33 years (18-40). All had severe polyarticular rheumatoid arthritis. Pre-operatively 12 ankles had no angular deformity, 9 were in valgus and 3 in varus. All had associated hindfoot disease. Some of these patients are part of two larger studies of the Scandinavian Total Ankle Replacement (STAR) and the Buechel-Pappas (BP) replacement. In this group there were 20 STAR and 4 BP replacements. Average follow-up was 62 months (36 to 120). Twenty-one replacements had good pain relief and function. The AOFAS hindfoot score for pain improved from 0 to 36 (max 40) and for function from 25 to 35 (max 60). Three have failed. One ankle had a 25-degree valgus deformity pre-operatively and this recurred and caused failure at 11 months. The second failed at 34 months due to aseptic loosening of the talar component. Both of these were converted to tibio-talo-calcaneal fusions with an intra-medullary nail. The third failure had never provided satisfactory pain relief in spite of appearing satisfactory on clinical and radiological examination. Exploratory surgery was carried out at 36 months but failed to produce an improvement and at 61 months the decision was made to revise the replacement to a fusion. However, due to concurrent health problems, this has not yet been done. We offer replacement to patients with severe polyarticular rheumatoid disease especially if there is a stiff but well aligned hindfoot. In the light of increased experience, we now consider valgus or varus deformity of greater than 20 degrees to be a contra-indication to replacement. This is because the deformity tends to recur leading to pain, loosening and failure.

We aim to assess the outcome of ankle arthrodesis performed for painful osteoarthritis in the presence of a coronal plane deformity of 20 degrees or more.

To our knowledge this is the first reported series of such a cohort of patients. We have a consecutive and complete series of 24 patients with 26 ankle arthrodeses which were all performed for painful osteoarthritis in the presence of large coronal plane deformity. These patients have a minimum of twelve months clinical follow-up. The results showed a low non-union rate of 8% (2 ankles). These have subsequently been re-fused satisfactorily, and are excluded from further analysis. The results of the remaining 24 ankles, which united primarily, show that patients were very pleased with the outcome of their surgery. AOFAS scores were used to measure pain and function, both pre-operatively and post-operatively. These scores showed large improvements for both pain and function, and had a high statistical significance (p<0.0001). All patients improved in their walking distance and many patients reduced their need for walking aids. Stair climbing ability was also improved in some patients. It is recognised that an ankle arthrodesis usually relieves pain but does not result in a normal gait and full function.

We feel that the high level of patient satisfaction in this series was due to the combination of deformity correction, restoring a functional foot position, and achieving a painless ankle. Arthroplasty of the ankle is a good procedure for relief of pain and restoration of function. However, in the presence of a large coronal plane deformity, ankle arthroplasty is known to fare badly with early failure. Therefore for patients with painful osteoarthritis and a coronal plane deformity of 20 degrees or more, we recommend ankle arthrodesis as the procedure of choice.

Material: 100 consecutively performed Total Ankle Arthroplasties (TAA) of the Mobility design carried out at Schultess Clinic Zurich and 100 from Wrightington Hospital Wigan were entered into the study. The male: female ratio was 1:1. Age 62 (range 24 to 95 years). The diagnosis was primary OA (59%), OA resulting from a major injury in the past (20%) and rheumatoid arthritis (21%). We considered more than 20 degrees varus or valgus to be a contraindication to TAA.

Methods: The Mobility TAA is three component, cobalt chrome uncemented design. The tibial component has a stem and the talar component has two fins for secure bony incorporation. At the time of TAA ancillary procedures such as gastrocnemius lengthening were performed if required.

Results: The follow-up was 36 months (24 to 50). The most frequently performed ancillary procedure was gastro-soleus lengthening and this was carried out in 20% of cases. Osteotomy of os calcis and talo-navicular or other hindfoot fusion was performed in approximately 8%. The severity of pain was measured on the visual analogue scale before and at follow-up and this improved from 8.5 to 1.6. The average range of motion measured radiographically improved from 25 deg to 30 deg. The most frequent persistent complaint was that of occasional troublesome antero-medial pain. 92% patients were satisfied with the outcome. Complications were 6% intra-operative malleolar fractures. These did not lead to long term problems. Delayed wound healing occurred in 4% but all healed fully by three months. Late medial malleolar fractures occurred in 2%. Early infection occurred in one patient and was successfully treated by washout and antibiotics. Revision to fusion or change of tibilal and/or talar implant was required in 2.5% (5 patients) due to aseptic loosening and a technical error in one further patient treated three years ago led to subluxation of the insert. This was changed for an 11mm insert with a successful outcome to present time.

Conclusion: These results are an improvement on those acheived by the same surgeons prior to this study using other types of implant. We believe this is due to improved instrumentation and implant design and a better understanding of the indications particularly the need to be very cautious in recommending replacement to patients with severe varus or valgus deformities.

Purpose: We evaluated the role of the Distal Tibial Line (DTL by Saltzman et al, 2005) in measuring the pre-operative and postoperative position of the talus on ‘lateral’ radiographs following a Total Ankle Replacement (TAR). Currently there is no validated measure of anteroposterior (AP) alignment of a TAR.

Arthritis in the ankle causes considerable malalignment in the anteroposterior plane. The DTL is not affected by the destruction of the tibiotalar joint and is independent of slight variations in the positioning of the foot and radiological magnification.

Method: DTL divides the talus into two sections and the proportionate length of the posterior segment is presented as a ratio. The size of the posterior segment and ratio decreases with anterior subluxation.

Radiographs of 200 cases of TAR were reviewed. The anterior and posterior outlines of the talus could not be seen in all cases (e.g. preoperative talonavicular fusion). As a result 49 cases of inflammatory arthritis (49 of 119) and 6 of osteoarthritis (6 of 81) could not be assessed.

Results: The osteoarthritic ankle (OA) in particular showed a tendency for anterior subluxation. The average ratio in OA cases increased from ‘34.8′ before surgery to ‘40.4’ after surgery, confirming a trend for this subluxation to reduce with a TAR.

There was a lesser tendency for subluxation in the inflammatory group of patients although the body of the talus itself was more deformed. The average preoperative value was ‘36.1’ and the post operative value was ‘38.9’.

Conclusion: We found the Distal Tibial line to be a reproducible parameter for measurement of AP alignment in TAR in the vast majority of OA cases. The change of anteroposterior alignment post surgery appears to be due to the restoration of soft tissue balance.

Patients undergoing total hip replacement (THR) often require further orthopaedic surgery including other primary lower limb joint replacements and revision surgery in their lifetime. We analysed the 10-year data of 552 patients who underwent primary total hip replacement between April 1991 and March 1992 at our institute. Data were available for all patients before the index operation. 77% of patients attended their 5-year review and 67% attended their 10-year review. 233 (42%) had had or subsequently had the opposite hip replaced. 30 patients (5%) had a knee replaced and 19 (3%) had both knees replaced. 4.4% underwent revision surgery.

Conclusion: nearly half the total number of these patients will in due course require the opposite hip replaced. 13% will need another major joint surgery (ie revision or TKR). At £6138 for a primary THR and £8500 for revision THR, and the cost of radiographs (£60) and follow-up appointment (£60), the approximate cost implications on a conservative estimate are £13,000.000. These factors including cost implications and human resource requirements will have significant influence on future planning of health care trusts.

Aim We set out to see

whether ankle replacements were capable of maintaining a normal gait and

Method We performed gait analysis on 15 patients, with 13 ankle replacements (mixture of Buechel Pappas and Scandinavian Total Ankle Replacement [STAR]) and three ankle arthrodeses. One patient had an ankle replacement on one side and an arthrodesis on the other. We used a standard seven camera infrared system and force plate at a frequency of 240Hz.

There were a mixture of patients with osteoarthritis and rheumatoid arthritis. We also looked at the ‘normal’ side of the patients with unilateral surgery.

Results We found that patients with ankle replacements had near normal gait parameters for both kinetic and kinematic data whereas patients with ankle fusions had significantly altered kinetic and kinematic data. This was both in respect to normal individuals and to the unoperated side. Patients with rheumatoid arthritis had some alteration in the gait pattern on the normal side – the presence of an ankle replacement on the other side maintained this pattern on the operated side, suggesting that this was not due to abnormalities within the ankle but in the rest of the foot and lower limb. Patients with unilateral osteoarthritis for which they had an ankle replacement had essentially normal kinetics and kinematics of both ankles.

Conclusion We have been able to show that an ankle replacement performs well in terms of restoring/maintaining a normal gait pattern, whereas ankle arthrodesis, although gives a functional and pain free foot, significantly alters the normal gait pattern.

Between 1993 and 1999, 119 total ankle arthroplasties (TAA) in 106 patients were performed. The prosthetic design in all cases was the Scandinavian Total Ankle Replacement (STAR). All patients have been reviewed annually.

Eight arthroplasties have been revised (see table for reasons for revision).

Twenty-four TAA were satisfactory at last review (4–87 months) in 19 patients who died. Annual review continues for 87 TAA. When last seen the average follow up was 72 months (48–123). The cumulative survival for all 119 TAA is 92% (see figure below).

Comment The complication of recurrent deformity causing ‘edge loading’ of the insert and failure can hopefully be avoided by not attempting arthroplasty in patients with more than 20 degrees of pre-operative valgus. The problem of aseptic loosening is harder to understand. Subsidence may be avoided by more accurate shaping of the talus to give better bony integration but osteolysis behind a well-fixed component remains an unsolved problem with respect to both its cause and treatment.

Aims: This study reports the mid-term results of a prospective series of 200 ankle replacements using the Scandinavian Total Ankle Replacement (STAR). 105 patients were more than five years since surgery.

Method: 200 patients; 85 male, 115 female; mean age 60 years (18–83) underwent primary replacement. The mean follow-up was 54 months (4–110). The diagnosis was inflammatory joint disease (IJD) for 119 patients and osteoarthritis (OA) for 81.

Results: 144 patients had a good outcome and uncomplicated recovery. A further 18 patients had a complication, which resolved with non-operative treatment (three prolonged wound healing, 15 malleolar fractures, either at surgery or at a later date). A further eight patients were clinically satisfactory but the x-rays showed adverse features (five aseptic loosening and three recurrent deformity). Five patients have a poor outcome due to persistent pain and stiffness but have not required further surgery. A further nine patients had a complication necessitating surgery (three calcaneal osteotomy and lateral ligament reconstruction, one tibial osteotomy to improve alignment, one autogenous bone graft for osteolysis, one for late medial malleolar fracture, one split skin graft for delayed healing, two for removal of heterotopic bone). At two years the AOFAS score for pain improved from 0 to 35 (maximum 40) and the functional score from 28 to 35 (maximum 60). There were 16 total failures that required fusion (11) or revision (five). The causes were nine aseptic loosening, three recurrent deformity, two fracture malleolus, one deep infection, one persistent pain. The cumulative five-year survival rate was 89% (95% CI 81% to 96%), with time to decision to revision or fusion as the endpoint.

Conclusions: There was no difference in survival between ankle replacement for OA or IJD. Ten out of the 16 failures occurred early (< two years), which we attribute to technical error or attempting replacement of ankles with severe deformity. The failure rate after two years is approximately 1% per annum.

Patients undergoing total hip replacement (THR) often require further orthopaedic surgery including other primary lower limb joint replacements and revision surgery in their lifetime. We analysed the 10-year data of 552 patients who underwent primary total hip replacement between April 1991 and March 1992 at our institute. Data was available for all patients before the index operation. 77% of patients attended their 5-year review and 67% attended their 10-year review. 233 (42%) had had or subsequently had the opposite hip replaced. 30 patients (5%) had a knee replaced and 19 (3%) had both knees replaced. 4.4% underwent revision surgery.

Concluding, nearly half the total number of these patients will in due course require the opposite hip replaced. 13% will need another major joint surgery (ie revision or TKR). At £6138 for a primary THR and £8500 for revision THR, and the cost of radiographs (£60) and follow-up appointment (£60), the approximate cost implications on a conservative estimate are 13 million pounds. For a single surgeon undertaking 40 THRs in a single year the cost would be approximately £900,000. In addition, the surgeon in 10 years practice would create enough work to last him the rest of his working lifetime. These factors including cost implications and human resource requirements will have significant influence on future planning of health care trusts.