A 66-year-old female presented with chief complaints of progressively worsening pain in the left ankle with inability to stand or walk, more so while walking over uneven surfaces for the past 8 months. On detailed history taking, no other specific positive points such as trauma, pain in other joints, or any constitutional symptoms were found. Clinical examination revealed diffuse tender horseshoe-shaped swelling all around subtalar joint with markedly restricted, painful subtalar joint movements. Her X-rays revealed a reduction of subtalar joint space with generalized osteoporosis (Fig. 1a and b). 20  and 40  Broden views also confirmed the presence of subtalar arthritis (Fig. 2a and b). All blood investigations including arthritic profile were within normal range. She was diagnosed as a case of seronegative type of subtalar joint arthritis. She underwent surgical intervention in the form of open subtalar joint arthrodesis with sinus tarsi approach. All, posterior, anterior, and medial facets of subtalar joints were prepared for sound fusion. Two 6.5 mm cannulated cancellous screws were used in compression mode for fixation. Screws were passed from non-weight bearing aspect of heel up to the neck of the talus. Additional anterior aspect of calcaneus was also used. This screw was 5.0 mm cannulated cancellous and was used with the purpose of sound fusion of middle and anterior subtalar joint (Fig. 3a and b). The patient being a case with severe osteoporosis, addition of proximal tibial bone grafts was done to augment fusion. Calcium and Vitamin D3 supplements were also added. Her post-operative course was uneventful. After removal of suture, a below knee plaster was applied for 4 weeks, and the patient was kept non-weight bearing. X-rays at 6 weeks post-surgery showed slow union (Fig. 4a-c). Teriparatide injections were added for enhancing union. X-rays at the end of 6 months did showed non-progressive and non-convincing progress of fusion (Fig. 5a-f). The patient was advised progressive weight bearing over 6 months. The patient always complained of persistence of swelling and pain on ambulation, which was treated with compression bandage and analgesics and anti-rheumatics.
The patient kept on coming back with complains of pain, difficulty in walking, and swelling in the foot without any other symptoms. Hematological investigations were repeated, which showed a rise of CRP (16 mm/L) and ESR (36 mm/h) with total leukocyte count being 12000. A course of intravenous broad-spectrum antibiotics (1.5 grams of cefoperazone andsulbactam twice a day plus 750 mg of amikacin once a day) was given for 3 weeks followed by 1 week of oral a ntibiotics (linezolid 600 mg twice a day) presuming a presence of low-grade infection. MRI could not be done because of the presence of stainless steel implants. Computed tomography scan at 8 months post-surgery showed the persistence of erosion and joint space at fusion site (Fig. 6a-c). Considering this as a case of non-union plus infection, it was decided to go for two staged surgical interventions, where first stage was planned as removal of implants and debridement and the second stage as revision fusion after a course of antibiotics. At second surgery through the same approach, implants were removed. Fusion was found to be incomplete. No pus discharge was noticed. Dirty granulation tissues were scrapped from the fusion site, and material was sent for histopathology examination. Postoperatively, the patient was immobilized in anterior and posterior below knee plaster splints. The same broad-spectrum intravenous antibiotics were continued. Histopathologic examination showed epithelioid granulomas with plenty of giant cells suggestive of tuberculosis (Fig. 7a and b). This was of a great surprise as the patient had no previous history of tuberculosis or any constitutive symptoms such as fever, night-pains, weight loss, or loss of appetite. The samples were reviewed at two other laboratories which also confirmed the diagnosis of tuberculosis. Antituberculosis treatment was started and the patient was given rest in the same below knee splint for 6 more weeks. Plan was to do revision fusion after 6 weeks under cover of antituberculous drugs. Serology showed improvement and so was patient. X-rays showed signs of fusion, and hence, surgery was delayed (Fig. 8a and b). Spontaneous fusion was noticed just with antituberculous medicines, and at the end of 3 months, fusion got completed and the patient was walking full weight bearing without any complaints (Fig. 9a-f).