Case of the Week #9: first metatarsophalangeal joint and interphalangeal joint arthritis
Updated: Sep 28, 2020
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Mrs M is a delightful 78 year old lady with a ten year history of right foot pain, on a background of extensive osteoarthritis to the hip, shoulder and knee. She was referred to Dr Touzell by another orthopaedic surgeon concerned about her ongoing foot pain. Mrs M described forefoot pain that stopped her from sleeping, and a sensation of walking on a stone underneath her great toe. She also had a prominent 'bunionette' deformity of the fifth metatarsal which stopped her from wearing most types of shoes. She had seen a podiatrist who had appropriately managed her foot deformity with a wider shoe and fortnightly debridement of her plantar first metatarsal and fifth metatarsal callosities, but she was becoming progressively more disabled by her foot pain. There was no history of gout or other inflammatory arthrropathy, and no history of diabetes and she was a lifetime non smoker.
Weight bearing x-rays of her foot (below) demonstrated extensive arthritis of the interphalangeal joint and the metatarsophalangeal joint of the great toe, as well as a type 1 bunionette deformity with enlargement of the fifth metatarsal head and lateral exostosis.
Arthritis of both the interphalangeal joint and metatarsophalangeal joint is difficult to treat. The most reliable orthopaedic surgical procedure to treat arthritis of these joints individually is an arthrodesis (fusion) which is well tolerated, but stiffening both of these joints can result in significant rigidity of the first ray of the foot. Multiple surgical options were discussed, and it was decided to proceed with a fusion of the interphalangeal joint, silicone 'hemi-cap' replacement of the first metatarsophalangeal joint as well as an osteotomy of the fifth metatarsal to treat her bunionette deformity.
Intra-operatively, Mrs M was noted to have very osteopaenic bone, common for women her age. Fixation of the fifth metatarsal osteotomy was difficult due to poor bone quality and the osteotomy was fixed with a simple wiring technique. The interphalangeal joint fusion and silicone 'hemi-cap' replacement of the first metatarsophalangeal joint was uncomplicated. She was heel weight bearing in a post-operative shoe for six weeks post operatively. Despite post-operative chemoprophylaxis, Mrs M still developed a DVT which was fortunately detected by her astute General Practitioner ten days post-operatively when Mrs M presented to her with calf pain. A letter of correspondence from her General Practitioner explaining her DVT diagnosis and treatment was extremely helpful and appreciated.
In addition, her suspected osteopaenia was relayed to her General Practitioner for further investigation and work-up.
Mrs M's six week post-operative x-ray demonstrated a successful fusion of the interphalangeal joint and union of the fifth metatarsal osteotomy (below) so the wire was removed in rooms.
Her first metatarsophalangeal joint was non-tender and had a 20deg range of motion (although this was less than her other side). One year later, her foot is completely pain free, she is able to wear off-the-shelf shoes with a low or no heel, and is recovering from a successful knee replacement.
This is an interesting case in an elderly lady with a combination of forefoot pathologies causing significant disability. This highlights the art of surgery, where a 'one size fits all' is not always best and sometimes using alternate surgical techniques can have good results. The silicone hemi-cap replacement is a reasonable surgical option for patients who may not be suitable for a fusion, although long-term results for this implant are lacking.
Key Learning Points:
Arthritis of the great toe can be very disabling.
DVT and PE is a common complication of foot and ankle surgery and clinicians need to investigate patients with postoperative calf pain, shortness of breath, chest pain or increased swelling of the lower limb.
Multiple surgical options for great toe arthritis are available, the most reliable being a fusion.
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