Forty-Year Outcome of Ankle "Cup" Arthroplasty for Post-Traumatic Arthritis

Abstract

Ankle arthroplasty for post-traumatic tibiotalar arthritis remains controversial. The current literature strongly recommends arthrodesis, especially in those patients who will overload the joint: the young, the active and the overweight patients. The case described here is a 40-year follow up. A 31-year old man underwent talar dome resurfacing with a custom Vitallium implant for post-traumatic arthritis in 1962. He continued to work as a heavy laborer until retirement in 1987 and presently remains virtually asymptomatic with regard to his foot and ankle.

The longevity of this individual implant has been remarkable. The unique design, minimal resection, surgical approach and remarkable success merit discussion in the light of publication of predominantly bleak reports of arthroplasty in this patient population.

INTRODUCTION

Traditionally, treatment for advanced ankle arthritis has been arthrodesis. Fears about long-term deterioration due to subjacent arthritis and the availability of motion-sparing ankle replacements resulted in their widespread use in the late 1970s and early 1980s. Unfortunately, for a variety of reasons, these early implants failed dramatically in active patients with post-traumatic arthritis.^2,3,4 As a result, total ankle replacement was not recommended for general use. There has been a resurgence of interest in arthroplasty with the introduction of uncemented semi-constrained designs with improved instrumentation and technique, with emphasis on alignment and limited bony resection.^4,5,6,7 However the longevity of these contemporary designs remains unknown.⁴

The purpose of this case report is to present the longest-term follow-up of any form of ankle replacement.

CASE REPORT

A 30-year old factory worker underwent internal fixation of a C-type ankle fracture following a motorbike accident in April 1960. When he was first seen at The University of Iowa Hospital one year following this injury, he was unable to work and complained of pain and stiffness in the ankle (Figure 1). Following an unsuccessful period of bracing, surgical options were considered. He and his surgeon, Dr. Carrol Larson, elected for an arthroplasty. At the time of surgery his range of motion was 10 degrees of plantarflexion beyond 10 degrees of fixed equinus. He had 15-20 degrees of subtalar motion. He weighed 250 pounds.

Figure 1.

Following manufacture of a radiographically approximated custom Vitallium mold of the upper surface of his talus, Dr. Larson performed the resurfacing in 1962 (Figure 2). This was achieved via a lateral approach exposing the entire distal fibula, which was osteotomized and reflected posteriorly. Intra-operatively, ankle motion was noted to be only two to three degrees. The articular surfaces were debrided and contoured and surrounding scar was excised. The intention was to keep the surfaces "congruent and parallel." The mold was inserted and range of movement of the ankle found to be about 10 degrees from plantigrade. The fibula was reduced and fixed with an intramedullary rush pin (Figure 3).

Figure 2.

Figure 3.

Figure 3A.

Figure 3B.

The patient's postoperative course was uneventful and by three months he was walking well, could walk on his toes and heels, and had an overall arc of sagittal plane movement of 40 degrees. By six months his gait was normal and he could walk several blocks. He returned to work at the John Deere factory as a machinist after nine months. By one and a half-years, he was noted to have improvement in his joint space. At six years he continued to work eight hours a day at John Deere and supplemented that with a further three to four hours a day of house painting. He had no difficulty climbing ladders. By ten years he was working up to 16 hours per day and doing additional concrete work at home. After ten days of carting wheelbarrow loads up a ramp from his basement, he noticed a "little pain on the top of his foot." This was diagnosed as lesser toe extensor tendonitis and resolved with rest.

He was first reviewed independently in 1980. He continued to work at his same position. He remained able to climb ladders and walk on uneven ground without difficulty. He was reviewed again in 1995, at the age of 64. His weight had remained constant at 252 pounds. He had retired from his factory work in 1987 but continued to walk up to five or six miles per day and to paint houses. On the American Foot and Ankle Society Ankle and Hindfoot Scale he scored 85/100. He had no pain and no activity limitation. He had some difficulty on uneven terrain, and with stairs or ladders. He walked with a mild limp and had a moderate restriction of range of motion. On examination he had mild hindfoot malalignment and only a mild reduction in subtalar motion compared to the contralateral side. He had 25 degrees of plantar flexion compared to 35 degrees on his unaffected side (Figure 4).

Figure 4.

Figure 4A.

Figure 4B.

Figure 4C.

Today, at 70 years of age, his arthritic knees limit his walking distance. He only experiences some discomfort in his ankle in the cold or when he first starts walking.

DISCUSSION

The first documented use of total ankle replacement was in 1970.¹ We could find no earlier reports of attempted ankle replacement. In 1962, Dr. Larson had extensive experience with cup arthroplasty of the hip, popularized by his mentor, Smith-Peterson. Metal implants with greater durability had recently been introduced. At the time, it was felt that resurfacing created an environment that restored cartilage thickness and a pain- free gliding surface. This apparent increased joint space was subsequently shown to be largely fibrous and fibrocartilaginous.

Paradoxically, it may have been fortunate for this patient that the improved results of total joint replacement for the hip, and eventually the knee, were yet to gain popular support. Ten years later, designs for a cemented total ankle became available but quickly and dramatically failed, especially in this young, heavy-laboring patient population. Failures were due to high rates of deep infection, extensive resection into poor supportive bone and early loosening due to excessive constraint.^2,3,4 In addition, longer-term follow up has shown worsening levels of patient satisfaction with these designs.^2,3

The lateral approach chosen by Dr. Larson could be useful in preventing early wound problems. His technique utilized minimal bone resection and clearly, in this case, excessive constraint or wear debris were not of any concern. Patient selection can not be overlooked as a major contributor to the success of the implant in this stoic individual.

The remarkable long-term success of a single custom implant does not demand a radical simplification of ankle replacement design. It should at least provoke thought as to why this implant might have survived, and stronger consideration for using a surgical approach and strategy for minimizing bony resection which could help improve outcomes of total ankle arthroplasty.