FOOT AND ANKLE
M. Siebachmeyer, K. Boddu, A. Bilal, T. W. Hester, T. Hardwick, T. P. Fox, M. Edmonds, V. Kavarthapu From King’s College Hospital NHS Foundation Trust, London, United Kingdom
M. Siebachmeyer, MRCS, Research Fellow, Department of Trauma and Orthopaedics K. Boddu, FRCS (Tr&Orth), Senior Fellow, Department of Trauma and Orthopaedics A. Bilal, MRCS, Orthopaedic Trainee, Department of Trauma and Orthopaedics T. W. Hester, BSc (Hons), MRCS, Orthopaedic Registrar, Department of Trauma and Orthopaedics T. Hardwick, MRCS, Orthopaedic Registrar, Department of Trauma and Orthopaedics T. P. Fox, BM BS, Junior Doctor, Department of Trauma and Orthopaedics M. Edmonds, MD, FRCP, Professor of Diabetic Foot Medicine, Diabetic Foot Clinic V. Kavarthapu, FRCS (Tr&Orth), Consultant Orthopaedic Surgeon, Department of Trauma and Orthopaedics King’s College Hospital NHS Foundation Trust, London SE5 9RT, UK. Correspondence should be sent to Mr V. Kavarthapu; e-mail: [email protected] ©2015 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.97B1. 34542 $2.00 Bone Joint J 2015;97-B:76–82. Received 26 May 2014; Accepted after revision 15 October 2014
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Outcome of one-stage correction of deformities of the ankle and hindfoot and fusion in Charcot neuroarthropathy using a retrograde intramedullary hindfoot arthrodesis nail We report the outcomes of 20 patients (12 men, 8 women, 21 feet) with Charcot neuroarthropathy who underwent correction of deformities of the ankle and hindfoot using retrograde intramedullary nail arthrodesis. The mean age of the patients was 62.6 years (46 to 83); their mean BMI was 32.7 (15 to 47) and their median American Society of Anaesthetists score was 3 (2 to 4). All presented with severe deformities and 15 had chronic ulceration. All were treated with reconstructive surgery and seven underwent simultaneous midfoot fusion using a bolt, locking plate or a combination of both. At a mean follow-up of 26 months (8 to 54), limb salvage was achieved in all patients and 12 patients (80%) with ulceration achieved healing and all but one patient regained independent mobilisation. There was failure of fixation with a broken nail requiring revision surgery in one patient. Migration of distal locking screws occurred only when standard screws had been used but not with hydroxyapatite-coated screws. The mean American Academy of Orthopaedic Surgeons Foot and Ankle (AAOS-FAO) score improved from 50.7 (17 to 88) to 65.2 (22 to 88), (p = 0.015). The mean Short Form (SF)-36 Health Survey Physical Component Score improved from 25.2 (16.4 to 42.8) to 29.8 (17.7 to 44.2), (p = 0.003) and the mean Euroqol EQ-5D-5L score improved from 0.63 (0.51 to 0.78) to 0.67 (0.57 to 0.84), (p = 0.012). Single-stage correction of deformity using an intramedullary hindfoot arthrodesis nail is a good form of treatment for patients with severe Charcot hindfoot deformity, ulceration and instability provided a multidisciplinary care plan is delivered. Cite this article: Bone Joint J 2015;97-B:76–82.
Charcot neuroarthropathy (CN) of the foot is a debilitating condition characterised by pathological fractures, subluxations or dislocations leading to disruption of the bony architecture of the foot and ankle. Although diabetes mellitus (DM) is the most common cause, CN may also be seen in syringomyelia, multiple sclerosis and hereditary neuropathy.1 The exact pathophysiology is still a matter of debate; however, sensory and motor neuropathy with loss of protective sensation and muscular atrophy lead to repetitive micro-trauma in the weight-bearing joints of the foot and ankle.1 Autonomic neuropathy can increase bone perfusion and resorption, leading to osteopenia, fracture and deformity.2 The deformities are often associated with chronic ulceration and osteomyelitis, which may eventually require amputation.3 Reconstruction may be undertaken with the aim of reducing the risk of ulceration by creating a stable plantigrade foot allowing the
patient to bear weight and mobilise, thereby decreasing the morbidity and the risk of amputation. Midfoot and forefoot reconstruction has been attempted with screws,4 bolts5 or external fixators6 with varying clinical outcomes.7 Surgical strategies for deformities of the hindfoot and ankle have included the use of intramedullary nails,8-12 ring fixators13 or a combination of both10 with or without simultaneous lengthening of the tendo-Achillis or gastrocnemius muscle.14 The intramedullary (IM) hindfoot fusion nail offers stable fixation and weight-bearing, allowing fusion and correction of the deformity. Although rates of fusion of > 70% have been described using this technique, there is a high rate of complications including nonunion, failure of fixation, infection and amputation.8-12 Patients often have long standing DM with a high prevalence of associated cardiac, renal and vascular co-morbidities, increasing the risk of anaesthetic and surgical complications.15 THE BONE & JOINT JOURNAL
OUTCOME OF ONE-STAGE CORRECTION OF DEFORMITIES OF THE ANKLE AND HINDFOOT AND FUSION IN CHARCOT NEUROARTHROPATHY
Unstable deformity
Assessment for PVD and infected ulceration
Patient with Charcot foot deformity
Stable deformity Assessment for PVD and infected ulceration
Ulcers?
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PVD?
Yes No
Infected?
Yes
Yes Corrective surgery • Hindfoot deformity Hindfoot correction and nail infusion • Midfoot deformity Exostectomy and/or corrective fusion • Forefoot deformity Exostectomy and/or corrective fusion
• Antibiotics • Debridement
Offloading regime
Chronic or recurrent ulceration
Yes
• Revascularisation procedures
No
Monitor
Fig. 1 Management algorithm for patients with Charcot foot deformity. Offloading regime comprises using total contact cast, pneumatic cast and foot and ankle orthotic (PVD, peripheral vascular disease).
Reconstructive treatment for patients with CN has therefore been offered in few specialist centres. Only three centres reported series with > 20 patients treated with a hindfoot nail fusion.8,10,12 Moreover the patient selfreported outcome measures (PROMs) in this population have not been described in the literature.14,16 We have a diabetic foot referral clinic in our university hospital with a multidisciplinary team that treats > 600 patients a year. The aim of this study was to report the outcome of treatment of patients with CN who underwent correction of deformities of the ankle and hindfoot and fusion using a retrograde IM nail.
Patients and Methods The multidisciplinary team comprises orthopaedic surgeons, endocrinologists, vascular surgeons, podiatrists, wound-care specialist nurses, orthotists, physiotherapists and occupational therapists. A treatment algorithm for the management of new referrals was established (Fig. 1). The initial assessment involves taking a thorough history and performing an examination including recording temperature difference, redness, tenderness, sensation, ulceration, deformities, tightness of the tendo-Achillis and the vascular status. Inflammatory markers such as C-reactive protein and white cell count as well as the diabetic status and glycaemic control are recorded. Dorsoplantar and lateral standing radiographs of both feet are obtained and VOL. 97-B, No. 1, JANUARY 2015
further imaging is performed to investigate suspected deep tissue or bone infection. CT imaging is performed routinely for all complex deformities. Swabs are sent for microbiological analysis for all patients with ulcers. A red, hot and swollen foot in the absence of infection is diagnosed as acute CN and is treated with a total contact cast (TCC)17 until the swelling and temperature difference has returned to normal. Patients with an unstable deformity of the foot and ankle, which is not amenable to bracing, are offered surgical treatment. Those patients with a CN and an active infected ulcer are treated with debridement, intravenous antibiotics and negative pressure wound therapy prior to definitive fusion. Feet with signs of peripheral vascular disease are re-vascularised prior to fusion. We identified 20 consecutive patients (12 men and 8 women) with CN who underwent reconstruction of the ankle and hindfoot between January 2008 and April 2013. Their mean age was 62.6 years (46 to 83). (Table I). One female patient underwent reconstruction of both feet. The mean weight of patients was 102.3 kg (36 to 158) and the mean BMI was 32.7 kg/m2 (15 to 47); four patients were morbidly obese with a BMI > 40. In all, 13 patients had type-2 and six had type-1 DM whereas one was not diabetic. The mean duration of DM at the time of surgery was 19.2 years (6 to 38). Glycaemic control was suboptimal in some patients, with a mean HbA1c of 7.7% (5.2% to 11.3%; target HbA1c: < 6.5%). All patients had evidence
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M. SIEBACHMEYER, K. BODDU, A. BILAL, T. W. HESTER, T. HARDWICK, T. P. FOX, M. EDMONDS, V. KAVARTHAPU
Table I. Description of individual patient characteristics ASA Patients Gender Age (yrs) grade
Fusion: Hindfoot (H), Time to fusion Minor revision* Midfoot (M) (mths) Major revision†
1 2 3
M F F
57 65 46
3 3 4
H H H
3.6 6.5 16.6
4 5 6
M F M
70 60 72
3 3 3
H H H
Fibrous 3.8 37.9
7 8 9 10
F M M M
83 62 78 59
3 3 3 3
H+M H H H+M
11 4.6 5.7 Non-union
11 12 13‡ 14‡ 15 16 17 18 19 20 21
M F F F M M M M F F M
77 61 50 50 76 53 52 69 61 50 56
3 3 3 3 3 3 3 3 3 3 2
H+M H H+M H+M H H H H H+M H+M H
4.4 3.6 3.8 9.8 2.9 2.9 6.2 3.5 4.5 2.2 4.6
Post-operative Chronic/recurrent Post-operative mobility status ulceration ulcer healing
Screw dislodgement* FWB FWB FWB Screw dislodgement,* Nail dynamisation* FWB Nail removal* FWB Nail breakage + FWB revision† FWB FWB FWB Nail dynamisation* FWB in CFO Midfoot revision† Midfoot revision† FWB Metal work removal* Chair bound Metal work removal* FWB in CFO Midfoot revision† FWB in CFO FWB FWB FWB FWB in OSO FWB FWB in CFO FWB in OSO
+ +
+
+ +
-
+ +
+ +
+
+
+ + + +
+ + + +
+ + + +
+ + + +
FWB, fully weight bearing; CFO, Custom Foot Orthoses (patient is FWB); OSO, off-shelf orthoses (patient is FWB) ASA American Society of Anesthesiologists grade ‡ 13 and 14 are right and left feet of the same patient
of peripheral neuropathy and six had a diabetic retinopathy. A total of 18 patients had chronic renal disease; 14 with stage 2, three had stage 3 and one had stage 4 renal disease.18 All patients were considered of increased risk for general anaesthesia: 18 patients were American Society of Anesthesiology (ASA)19 grade III; one was grade II and one was grade IV. Chronic or recurrent ulceration was noted in 15 feet with some patients having undergone up to four years of conservative management. Of these, 11 had residual ulceration at the time of surgery around the hindfoot, in spite of an offloading regime and standard wound care including debridement and negative pressure therapy. Four patients had instability of the ankle and/or subtalar joint. Two were referred for revascularisation procedures prior to reconstruction; one underwent peroneal angioplasty and one femoral endarterectomy and a patch angioplasty. All were treated using a hindfoot arthrodesis nail (TRIGEN Hindfoot Fusion Nail, Smith & Nephew, Memphis, Tennessee). Surgery was undertaken by a single surgeon (VK) using a standard technique (Figs 2 and 3). During the course of the study the standard distal locking screws were replaced by hydroxyapatite-(HA) coated screws as standard screws had migrated in two patients during the early part of the study. Patients with additional midfoot deformities were treated with simultaneous midfoot fusion using a bolt and/or a locking plate. Correction of the deformity was achieved by resecting a wedge of bone through a single incision on the convex side
of the deformity where possible and stabilised with the hindfoot fusion nail. An extended lateral approach, including a proximal translateral malleolar approach to the ankle and more distally directly over the subtalar joint was used for a varus ankle and hindfoot deformity. A two-incision approach was used for valgus deformities, involving an anteromedial approach to the ankle and a separate lateral approach to the subtalar joint. The residual midfoot deformity was corrected using a separate incision over the apex of the deformity, with the principles of wedge resection and plate and/or intramedullary stabilisation. The concept of a ‘super construct’20 was used for stabilisation of the deformity. This required fixation to be extended beyond the zone of Charcot involvement of the midfoot into the uninvolved first tarso-metatarsal joint to provide a long segment of fixation. Deep tissue samples were sent for microbiological assessment. Minor tightness of the tendo-Achillis often improved following wedge resection. Percutaneous lengthening of the tendo-Achillis was performed using multiple stab wounds if there was a severe contracture. Bone graft substitutes were used as required before closure over a drain. Post-operative wound management was supervised by the multi-disciplinary team. Non weight-bearing was continued for at least three months followed by partial weight-bearing for three more months, guided by the radiological and clinical progression of healing. Full weight-bearing in a removable brace was allowed thereafter, once union was shown on radiographs or CT scans. The THE BONE & JOINT JOURNAL
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Fig. 2a
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Fig. 2b
Fig. 2c a) Pre-operative clinical photograph and radiograph, b) post-operative clinical photographs and c) two weeks post-operative radiograph showing hindfoot nail fusion of the left ankle in a 50-year-old female patient. The arrowhead (a) indicates the side of interest. The patient had additional midfoot fusion using bolt and plate and hallux stabilisation simultaneously. The deformity correction and post-operative healing of a long-term medial malleolar ulcer are illustrated.
Fig. 3a
Fig. 3b
a) Pre- and b) 6-month post-operative radiographs showing bony fusion at 4.6 months in a 62-year-old male patient who presented with a left-sided Charcot foot deformity and multiple ulcers. This patient underwent peroneal angioplasty before proceeding to hindfoot nail arthrodesis.
patients were then allowed to progress to full weight-bearing using well-fitting lace-up shoes or custom-made foot wear. The migration of distal locking screws was measured six months post-operatively in comparison with the immediate post-operative appearance. In order to eliminate the effect of rotation and magnification of two different radiographs, the ratio of the proximal part of the screw to its total length was calculated to enable estimation of the amount of VOL. 97-B, No. 1, JANUARY 2015
migration as a percentage of the total length of the screw. Migration of > 2.0% of the length of the screw was considered to be significant as in control measurements, it was observed that the average error using this method was between 0% and 2% and that a dislodgement of < 2% could therefore not reliably be detected. The outcome measures which were used included the American Academy of Orthopaedic Surgeons Foot and
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Table II. Outcomes of treatment Outcome of treatment
Number, (range/%)
Mean follow-up (mths) Limb salvage (feet) Ulcer healing Return to FWB FWB in custom foot orthoses FWB in off shelf orthoses Wheel chair bound Tibiotalar fusion Radiological fusion Stable fibrous fusion Nonunion Mean time to fusion (mths) FWB, fully weight bearing
25 (8 to 54) 21 (100) 12 of 15 (80) 20 (95) 4 (20) 2 (10) 1 (5) 19 (90) 1 (5) 1 (5) 7.3 (2.2 to 38)
Table III. Patient self-reported outcomes scores (PROMs), before and after surgery PROMs
Before surgery
After surgery
Z-value
p-value
AAOS-FAO EQ-5D-5L SF-36 PCS SF-36 MCS SF-36 physical functioning SF-36 bodily pain* SF-36 social functioning
50.7 0.63 25.2 48.7 25.9 34.3 33.6
65.2 0.67 29.8 48.7 29.2 41.0 39.5
-2.49 -2.52 -2.93 -1.780 -2.539 -2.53 -2.36
0.013 0.012 0.003 0.075 0.011 0.012 0.042
PCS, Physical Component Summary; MCS, Mental Component Summary; AAOS-FAO, American Academy of Orthopaedic Surgeons-Foot and Ankle Outcomes; SF-36, short-form-36 * higher sore is less pain. The Wilcoxon signed-rank test was used to calculate p-values
Ankle Outcomes (AAOS-FAO),21 Short Form (SF)-36 Health Survey22 and the Euroqol EQ-5D-5L23 which were recorded pre- and post-operatively. The following were also recorded: limb salvage, the achievement of full weight-bearing, the healing of ulcers, bony fusion and revision surgery. Statistical analysis. The Wilcoxon signed-rank test was used to examine differences for statistical significance, which was defined as a p-value < 0.05
Results All patients (21 feet) underwent hind foot deformity correction and tibiocalcaneal fusion using the IM hindfoot fusion nail. A total of seven patients (seven feet) underwent simultaneous midfoot fusion which was achieved using a medial column bolt alone in four patients, a bolt augmented by a locking plate in two and a dorsal locking plate alone in one patient. Two patients underwent simultaneous first metatarsophalangeal joint fusion. Two required percutaneous lengthening of the tendo-Achillis. One had a split skin graft at the time of initial surgery. The mean follow-up was 26 months (8 to 54). Limb salvage was achieved in all patients (Table II). Patient satisfaction and function improved as reflected by all three PROMs (Table III). One patient died due to a cerebrovascular accident, four years after surgery. Healing of the ulcer was achieved in 12 of 15 patients (12 of 15 feet) who had ulceration pre-operatively at a median of 8 months
(6 to 13) post-operatively. All but one patient achieved full weight-bearing, with patients wearing well-fitting shoes. Three (four feet) required a custom-made ankle-foot orthosis and two needed a pneumatic walking brace. One patient remained wheel-chair bound. Fusion was achieved radiologically in 19 of 21 feet (90%); one had a stable painless pseuodoarthrosis. One fusion failed to unite. Two patients underwent nail removal due to complications. In one patient, the fixation failed and the nail broke, requiring removal of the nail and revision fixation. The nail was removed in another patient due to a non-healing ulcer over the sole at the site of insertion of the nail. Three reconstructions required dynamisation of the nail by removal of proximal locking screws to enhance fusion. In three of the four feet in which simultaneous midfoot fusion using a bolt alone was undertaken, the bolt migrated, requiring revision using a locking plate. Four of 22 standard distal locking screws (18%), in two patients, migrated by approximately one third of the length of the screw. None of the 34 HA coated locking screws migrated.
Discussion These results show that single-stage reconstuction and internal fixation in patients with severe Charcot ankle and hindfoot deformity can achieve healing of chronic ulcers and independent mobilisation with appropriate THE BONE & JOINT JOURNAL
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supplementary orthoses in most patients. These improvements in outcome were associated with significantly better quality of life as reflected by PROMs after surgery. The rate of major complications following hindfoot nail arthrodesis is significantly higher in patients with diabetic neuroarthopathy.24 Consequently, reconstruction has been limited to a few centres with few reports involving large series. In Charcot feet without chronic ulceration, Dalla Paola et al11 achieved 100% limb salvage and a 77.8% rate of fusion (n = 18). Similarly, a 100% limb salvage and rate of fusion using a longer IM femoral nail was reported in a smaller study including nine patients with Charcot feet without ulcers.25 However, the results of hindfoot nail arthrodesis in Charcot feet with ulcers have been poorer. Caravaggi et al8 reported 45 patients, seven with chronic ulcers, with a rate of limb salvage of 86.7%. Pinzur and Kelikian12 reported a cohort of 21 patients, eight with chronic ulcers, with a rate of limb salvage of 95.2% and a rate of fusion of 90.5 %. With 12 feet (26%) having preoperative ulceration, DeVries et al10 showed a higher rate of amputation (22%) in their cohort of 45 Charcot feet. In contrast we achieved 100% limb salvage in our patients with 71% of feet having chronic ulceration and 52% feet having ulcers at the time of surgery. Improvement in PROMs in our patients suggests that the salvaged limbs had satisfactory function. With our approach, the presence of a pre-operative ulcer does not seem to be a contraindication for using an internal fixation device such as an IM nail for fusion in these patients. The combination of DM, peripheral neuropathy, obesity, impaired renal function and other cardio-vascular comorbidities raises the peri-operative morbidity and mortality.26 These patients characteristically have wounds which heal poorly due to loss of protective sensation and to long-standing DM that increases the risk of peripheral arterial disease and microvascular dysfunction with impaired tissue oxygenation.27 Correction of deformity, meticulous wound management and a pressure offloading regime resulted in a rate of ulcer healing of 80%. All wounds healed initially but ulcers developed later due to prominent metal work in two feet; the wounds healed after removal of metal work. Complications were mostly noted in relation to midfoot fusion using a medial column bolt in patients who underwent simultaneous midfoot reconstruction. However, no further complications occurred following revision to fusion using a locking plate. Although medial column fusion alone has been shown to be successful in a small study (n = 5),28 performing this as a procedure in addition to hindfoot nail fusion in feet with severe deformities at many sites resulted in a high rate of revision in our study. More recently, the use of external ring fixators in patients with CN has become popular as an alternative to IM fixation. Pinzur et al29 reported the largest cohort (n = 178), with a rate of limb salvage of 95.7%. In their study, 45 of 73 patients (62%) who had an ulcer achieved healing after VOL. 97-B, No. 1, JANUARY 2015
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surgery. Fragomon et al30 reported a rate of limb salvage of 95% and a rate of union of 73% using an Ilizarov frame, with one frame revision and four tibial stress fractures in a series of 19 patients. Dalla Paola et al13 and El-Gafary et al31 achieved rates of limb salvage of 89% (n = 45) and 100% (n = 20), respectively. One study compared the use of an IM nail alone to nailing combined with the use of a circular external fixator and concluded the latter may add extra stability to the construct.10 No study has directly compared the results of different surgical techniques, or of reconstruction versus amputation. Our study showed that similar or better results can be obtained in these patients with reconstruction using a hindfoot nail, thereby avoiding the problems associated with external fixation, such as poor compliance, the need for several operations, meticulous long-term pin tract care, and a negative psychological impact.32,33 The durability of fixation following Charcot hindfoot fusion is paramount, as the time to fusion is often > three months and the bone is usually osteopenic. The arthrodesis nail used in this study has threaded distal screw holes to improve engagement and thereby reduce the risk of migration of the screw. Nevertheless, non-HA coated locking screws showed significant migration six months post-operatively. This effect is well known in mechanical engineering as rotational loosening in bolted joints due to cyclic transverse loads.34,35 Factors increasing the threshold of loosening are an increased frictional coefficient, steeper thread lead angle, finer threads, increased preload and the use of adjuncts such as fasteners. In biological tissue, HA coating increases the torque of screws during insertion and extraction compared to standard screws.36 In addition, the potential for bony on-growth on the screws may further increase the self-loosening threshold of distal locking screws. These factors probably contributed to the superior fixation of HA coated screws as there was no migration or osteolysis around these screws. Following reconstruction of a foot in patients with CN, close monitoring and care in a multi-disciplinary team is required to avoid complications in these complex patients. This extensive care is time consuming and expensive and this may serve as an argument for proponents of amputation. However, a cost comparison study of limb salvage (n = 76) versus amputation (n = 17) in patients with CN could not find any difference within the first year.37 A total of nine of our patients were offered amputation elsewhere and were referred to our centre for a further opinion. We acknowledge that there are limitations to this study. The outcome of treatment was not compared with a control group, but a randomised controlled trial in such a diverse and complex group of patients is practically challenging. Although our series involves a small number of patients, with few centres undertaking this approach, the numbers of patients available is limited. A multicentre, prospective, randomised controlled trial would be the best way to shed more light on this approach.
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In summary, we report satisfactory outcome following corrective fusion of severe deformities of the ankle and hindfoot in patients with CN treated with a hindfoot intramedullary nail. Most patients achieved healing of an ulcer and independent mobilisation. Complications occurred mostly in patients who underwent simultaneous midfoot fusion using a bolt. Initial results also suggest that HA coating of distal locking screws may achieve better fixation. M. Siebachmeyer: Data collection, Writing and editing the manuscript, Checking the proof. K. Boddu: Writing and editing the manuscript, Checking the proof A. Bilal; Co-author, Data collection. T. W. Hester; Co-author, Data collection. T. Hardwick; Data collection. T. Fox; Data collection. M. Edmonds: Writing and editing the manuscript, Checking the proof. V. Kavarthapu: Writing and editing the manuscript, Checking the proof. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by G. Scott and first proof edited by J. Scott.
References 1. Kaynak G, Birsel O, Güven MF, et al. An overview of the Charcot foot pathophysiology. Diabet Foot Ankle 2013;4. 2. Blakytny R, Spraul M, Jude EB. Review: The diabetic bone: a cellular and molecular perspective. Int J Low Extrem Wounds 2011;10:16–32. 3. Shaikh N, Vaughan P, Varty K, Coll AP, Robinson AH. Outcome of limited forefoot amputation with primary closure in patients with diabetes. Bone Joint J 2013;95B:1083–1087. 4. Lamm BM, Siddiqui NA, Nair AK, et al. Intramedullary foot fixation for midfoot Charcot neuroarthropathy. J Foot Ankle Surg 2012;51:531–536. 5. Wiewiorski M, Yasui T, Miska M, et al. Valderrabano V Solid bolt fixation of the medial column in Charcot midfoot arthropathy. J Foot Ankle Surg 2013;52:88–94. 6. Stapleton JJ, Zgonis T. Surgical reconstruction of the diabetic Charcot foot: internal, external or combined fixation? Clin Podiatr Med Surg 2012;29:425–433. 7. Crim BE, Lowery NJ, Wukich DK. Internal fixation techniques for midfoot charcot neuroarthropathy in patients with diabetes. Clin Podiatr Med Surg 2011;28:673–685. 8. Caravaggi CM, Sganzaroli AB, Galenda P, et al. Long-term follow-up of tibiocalcaneal arthrodesis in diabetic patients with early chronic Charcot osteoarthropathy. J Foot Ankle Surg 2012;5:408–411. 9. Caravaggi C, Cimmino M, Caruso S, et al. Intramedullary compressive nail fixation for the treatment of severe Charcot deformity of the ankle and rear foot. J Foot Ankle Surg 2006;45:20–24. 10. DeVries JG, Berlet GC, Hyer CF. A retrospective comparative analysis of Charcot ankle stabilization using an intramedullary rod with or without application of circular external fixator--utilization of the Retrograde Arthrodesis Intramedullary Nail database. J Foot Ankle Surg 2012;51:420–425. 11. Dalla Paola L, Volpe A, Varotto D, et al. Use of a retrograde nail for ankle arthrodesis in Charcot neuroarthropathy: a limb salvage procedure. Foot Ankle Int 2007;28:967–970. 12. Pinzur MS, Kelikian A. Charcot ankle fusion with a retrograde locked intramedullary nail. Foot Ankle Int 1997;18:699–704. 13. Dalla Paola L, Brocco E, Ceccacci T, et al. Limb salvage in Charcot foot and ankle osteomyelitis: combined use single stage/double stage of arthrodesis and external fixation. Foot Ankle Int 2009;30:1065–1070.
14. Lowery NJ, Woods JB, Armstrong DG, et al. .Surgical management of Charcot neuroarthropathy of the foot and ankle: a systematic review. Foot Ankle Int 2012;33:113–121. 15. Wukich DK, Lowery NJ, McMillen RL, et al. Postoperative infection rates in foot and ankle surgery: a comparison of patients with and without diabetes mellitus. J Bone Joint Surg [Am] 2010;92-A:287–295. 16. Frykberg RG, Sage RA, Wukich DK, et al. Charcot arthropathy. Foot Ankle Spec 2012;5:262–271. 17. Edmonds ME, Foster AVM, Sanders L. A practical manual of diabetic foot care. 2nd Ed; Wiley-Blackwell, 2008. 18. Levey AS, Coresh J, Balk E, et al. National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Ann Intern Med 2003;139:137–147. 19. No authors listed. American Society of Anesthesiologists. https://www.asahq.org/ clinical/physicalstatus.htm (date last accessed 2 December 2014). 20. Sammarco, VJ; Chevillet, J. The Role of Internal Fixation in Surgery of the Charcot Foot and the Evolution of ‘Super-Construct’ Techniques. Current Orthopaedic Practice 2010;21:233–239. 21. Johanson NA, Liang MH, Daltroy L, Rudicel S, Richmond J. American Academy of Orthopaedic Surgeons lower limb outcomes assessment instruments. Reliability, validity, and sensitivity to change. J Bone Joint Surg [Am] 2004;86-A:902–909. 22. Ware JE, Sherbourne CD. The MOS 36-item short-form health survey (SF-36). I. Conceptual framework and item selection. Med Care 1992;30:473–483. 23. Herdman M, Gudex C, Lloyd A, et al. Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Qual Life Res 2011;20:1727–1736. 24. Mendicino RW, Catanzariti AR, Saltrick KR, et al. Tibiotalocalcaneal arthrodesis with retrograde intramedullary nailing. J Foot Ankle Surg 2004;43:82–86. 25. Pinzur MS, Noonan T. Ankle arthrodesis with a retrograde femoral nail for Charcot ankle arthropathy. Foot Ankle Int 2005;26:545–549. 26. Guo S, Dipietro LA. Factors affecting wound healing. J Dent Res 2010;89:219–229. 27. Apelqvist J. Diagnostics and treatment of the diabetic foot. Endocrine 2012;41:384– 397. 28. Cullen BD, Weinraub GM, Van Gompel G. Early results with use of the midfoot fusion bolt in Charcot arthropathy. J Foot Ankle Surg 2013;5:235–238. 29. Pinzur MS, Gil J, Belmares J. Treatment of osteomyelitis in charcot foot with single-stage resection of infection, correction of deformity, and maintenance with ring fixation. Foot Ankle Int 2012;33:1069–1074. 30. Fragomen AT, Borst E, Schachter L, et al. Complex ankle arthrodesis using the Ilizarov method yields high rate of fusion. Clin Orthop Relat Res 2012;470:2864–2873. 31. El-Gafary KA, Mostafa KM, Al-Adly WY. The management of Charcot joint disease affecting the ankle and foot by arthrodesis controlled by an Ilizarov frame: early results. J Bone Joint Surg [Br] 2009;91-B:1322–1325. 32. Madhusudhan TR, Ramesh B, Manjunath K, et al. Outcomes of Ilizarov ring fixation in recalcitrant infected tibial non-unions - a prospective study. J Trauma Manag Outcomes 2008;2:6. 33. Santy J, Vincent M, Duffield B. The principles of caring for patients with Ilizarov external fixation. Nurs Stand 2009;23:50–55. 34. Bickford JH, Nassar S. Handbook of bolts and bolted joints. New York: Marcel Dekker; 1998. 35. Sanclemente JA, Hess DP. Parametric study of threaded fastener loosening due to cyclic transverse loads. Eng Fail Anal 2007;14:239–249. 36. Sandén B, Olerud C, Petrén-Mallmin M, et al. Hydroxyapatite coating improves fixation of pedicle screws. A clinical study. J Bone Joint Surg [Br] 2002;84:387–391. 37. Gil J, Schiff AP, Pinzur MS. Cost comparison: limb salvage versus amputation in diabetic patients with charcot foot. Foot Ankle Int 2013;34:1097–1099.
THE BONE & JOINT JOURNAL
M. Siebachmeyer, K. Boddu, A. Bilal, T. W. Hester, T. Hardwick, T. P. Fox, M. Edmonds, V. Kavarthapu From King’s College Hospital NHS Foundation Trust, London, United Kingdom
M. Siebachmeyer, MRCS, Research Fellow, Department of Trauma and Orthopaedics K. Boddu, FRCS (Tr&Orth), Senior Fellow, Department of Trauma and Orthopaedics A. Bilal, MRCS, Orthopaedic Trainee, Department of Trauma and Orthopaedics T. W. Hester, BSc (Hons), MRCS, Orthopaedic Registrar, Department of Trauma and Orthopaedics T. Hardwick, MRCS, Orthopaedic Registrar, Department of Trauma and Orthopaedics T. P. Fox, BM BS, Junior Doctor, Department of Trauma and Orthopaedics M. Edmonds, MD, FRCP, Professor of Diabetic Foot Medicine, Diabetic Foot Clinic V. Kavarthapu, FRCS (Tr&Orth), Consultant Orthopaedic Surgeon, Department of Trauma and Orthopaedics King’s College Hospital NHS Foundation Trust, London SE5 9RT, UK. Correspondence should be sent to Mr V. Kavarthapu; e-mail: [email protected] ©2015 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.97B1. 34542 $2.00 Bone Joint J 2015;97-B:76–82. Received 26 May 2014; Accepted after revision 15 October 2014
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Outcome of one-stage correction of deformities of the ankle and hindfoot and fusion in Charcot neuroarthropathy using a retrograde intramedullary hindfoot arthrodesis nail We report the outcomes of 20 patients (12 men, 8 women, 21 feet) with Charcot neuroarthropathy who underwent correction of deformities of the ankle and hindfoot using retrograde intramedullary nail arthrodesis. The mean age of the patients was 62.6 years (46 to 83); their mean BMI was 32.7 (15 to 47) and their median American Society of Anaesthetists score was 3 (2 to 4). All presented with severe deformities and 15 had chronic ulceration. All were treated with reconstructive surgery and seven underwent simultaneous midfoot fusion using a bolt, locking plate or a combination of both. At a mean follow-up of 26 months (8 to 54), limb salvage was achieved in all patients and 12 patients (80%) with ulceration achieved healing and all but one patient regained independent mobilisation. There was failure of fixation with a broken nail requiring revision surgery in one patient. Migration of distal locking screws occurred only when standard screws had been used but not with hydroxyapatite-coated screws. The mean American Academy of Orthopaedic Surgeons Foot and Ankle (AAOS-FAO) score improved from 50.7 (17 to 88) to 65.2 (22 to 88), (p = 0.015). The mean Short Form (SF)-36 Health Survey Physical Component Score improved from 25.2 (16.4 to 42.8) to 29.8 (17.7 to 44.2), (p = 0.003) and the mean Euroqol EQ-5D-5L score improved from 0.63 (0.51 to 0.78) to 0.67 (0.57 to 0.84), (p = 0.012). Single-stage correction of deformity using an intramedullary hindfoot arthrodesis nail is a good form of treatment for patients with severe Charcot hindfoot deformity, ulceration and instability provided a multidisciplinary care plan is delivered. Cite this article: Bone Joint J 2015;97-B:76–82.
Charcot neuroarthropathy (CN) of the foot is a debilitating condition characterised by pathological fractures, subluxations or dislocations leading to disruption of the bony architecture of the foot and ankle. Although diabetes mellitus (DM) is the most common cause, CN may also be seen in syringomyelia, multiple sclerosis and hereditary neuropathy.1 The exact pathophysiology is still a matter of debate; however, sensory and motor neuropathy with loss of protective sensation and muscular atrophy lead to repetitive micro-trauma in the weight-bearing joints of the foot and ankle.1 Autonomic neuropathy can increase bone perfusion and resorption, leading to osteopenia, fracture and deformity.2 The deformities are often associated with chronic ulceration and osteomyelitis, which may eventually require amputation.3 Reconstruction may be undertaken with the aim of reducing the risk of ulceration by creating a stable plantigrade foot allowing the
patient to bear weight and mobilise, thereby decreasing the morbidity and the risk of amputation. Midfoot and forefoot reconstruction has been attempted with screws,4 bolts5 or external fixators6 with varying clinical outcomes.7 Surgical strategies for deformities of the hindfoot and ankle have included the use of intramedullary nails,8-12 ring fixators13 or a combination of both10 with or without simultaneous lengthening of the tendo-Achillis or gastrocnemius muscle.14 The intramedullary (IM) hindfoot fusion nail offers stable fixation and weight-bearing, allowing fusion and correction of the deformity. Although rates of fusion of > 70% have been described using this technique, there is a high rate of complications including nonunion, failure of fixation, infection and amputation.8-12 Patients often have long standing DM with a high prevalence of associated cardiac, renal and vascular co-morbidities, increasing the risk of anaesthetic and surgical complications.15 THE BONE & JOINT JOURNAL
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Unstable deformity
Assessment for PVD and infected ulceration
Patient with Charcot foot deformity
Stable deformity Assessment for PVD and infected ulceration
Ulcers?
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PVD?
Yes No
Infected?
Yes
Yes Corrective surgery • Hindfoot deformity Hindfoot correction and nail infusion • Midfoot deformity Exostectomy and/or corrective fusion • Forefoot deformity Exostectomy and/or corrective fusion
• Antibiotics • Debridement
Offloading regime
Chronic or recurrent ulceration
Yes
• Revascularisation procedures
No
Monitor
Fig. 1 Management algorithm for patients with Charcot foot deformity. Offloading regime comprises using total contact cast, pneumatic cast and foot and ankle orthotic (PVD, peripheral vascular disease).
Reconstructive treatment for patients with CN has therefore been offered in few specialist centres. Only three centres reported series with > 20 patients treated with a hindfoot nail fusion.8,10,12 Moreover the patient selfreported outcome measures (PROMs) in this population have not been described in the literature.14,16 We have a diabetic foot referral clinic in our university hospital with a multidisciplinary team that treats > 600 patients a year. The aim of this study was to report the outcome of treatment of patients with CN who underwent correction of deformities of the ankle and hindfoot and fusion using a retrograde IM nail.
Patients and Methods The multidisciplinary team comprises orthopaedic surgeons, endocrinologists, vascular surgeons, podiatrists, wound-care specialist nurses, orthotists, physiotherapists and occupational therapists. A treatment algorithm for the management of new referrals was established (Fig. 1). The initial assessment involves taking a thorough history and performing an examination including recording temperature difference, redness, tenderness, sensation, ulceration, deformities, tightness of the tendo-Achillis and the vascular status. Inflammatory markers such as C-reactive protein and white cell count as well as the diabetic status and glycaemic control are recorded. Dorsoplantar and lateral standing radiographs of both feet are obtained and VOL. 97-B, No. 1, JANUARY 2015
further imaging is performed to investigate suspected deep tissue or bone infection. CT imaging is performed routinely for all complex deformities. Swabs are sent for microbiological analysis for all patients with ulcers. A red, hot and swollen foot in the absence of infection is diagnosed as acute CN and is treated with a total contact cast (TCC)17 until the swelling and temperature difference has returned to normal. Patients with an unstable deformity of the foot and ankle, which is not amenable to bracing, are offered surgical treatment. Those patients with a CN and an active infected ulcer are treated with debridement, intravenous antibiotics and negative pressure wound therapy prior to definitive fusion. Feet with signs of peripheral vascular disease are re-vascularised prior to fusion. We identified 20 consecutive patients (12 men and 8 women) with CN who underwent reconstruction of the ankle and hindfoot between January 2008 and April 2013. Their mean age was 62.6 years (46 to 83). (Table I). One female patient underwent reconstruction of both feet. The mean weight of patients was 102.3 kg (36 to 158) and the mean BMI was 32.7 kg/m2 (15 to 47); four patients were morbidly obese with a BMI > 40. In all, 13 patients had type-2 and six had type-1 DM whereas one was not diabetic. The mean duration of DM at the time of surgery was 19.2 years (6 to 38). Glycaemic control was suboptimal in some patients, with a mean HbA1c of 7.7% (5.2% to 11.3%; target HbA1c: < 6.5%). All patients had evidence
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Table I. Description of individual patient characteristics ASA Patients Gender Age (yrs) grade
Fusion: Hindfoot (H), Time to fusion Minor revision* Midfoot (M) (mths) Major revision†
1 2 3
M F F
57 65 46
3 3 4
H H H
3.6 6.5 16.6
4 5 6
M F M
70 60 72
3 3 3
H H H
Fibrous 3.8 37.9
7 8 9 10
F M M M
83 62 78 59
3 3 3 3
H+M H H H+M
11 4.6 5.7 Non-union
11 12 13‡ 14‡ 15 16 17 18 19 20 21
M F F F M M M M F F M
77 61 50 50 76 53 52 69 61 50 56
3 3 3 3 3 3 3 3 3 3 2
H+M H H+M H+M H H H H H+M H+M H
4.4 3.6 3.8 9.8 2.9 2.9 6.2 3.5 4.5 2.2 4.6
Post-operative Chronic/recurrent Post-operative mobility status ulceration ulcer healing
Screw dislodgement* FWB FWB FWB Screw dislodgement,* Nail dynamisation* FWB Nail removal* FWB Nail breakage + FWB revision† FWB FWB FWB Nail dynamisation* FWB in CFO Midfoot revision† Midfoot revision† FWB Metal work removal* Chair bound Metal work removal* FWB in CFO Midfoot revision† FWB in CFO FWB FWB FWB FWB in OSO FWB FWB in CFO FWB in OSO
+ +
+
+ +
-
+ +
+ +
+
+
+ + + +
+ + + +
+ + + +
+ + + +
FWB, fully weight bearing; CFO, Custom Foot Orthoses (patient is FWB); OSO, off-shelf orthoses (patient is FWB) ASA American Society of Anesthesiologists grade ‡ 13 and 14 are right and left feet of the same patient
of peripheral neuropathy and six had a diabetic retinopathy. A total of 18 patients had chronic renal disease; 14 with stage 2, three had stage 3 and one had stage 4 renal disease.18 All patients were considered of increased risk for general anaesthesia: 18 patients were American Society of Anesthesiology (ASA)19 grade III; one was grade II and one was grade IV. Chronic or recurrent ulceration was noted in 15 feet with some patients having undergone up to four years of conservative management. Of these, 11 had residual ulceration at the time of surgery around the hindfoot, in spite of an offloading regime and standard wound care including debridement and negative pressure therapy. Four patients had instability of the ankle and/or subtalar joint. Two were referred for revascularisation procedures prior to reconstruction; one underwent peroneal angioplasty and one femoral endarterectomy and a patch angioplasty. All were treated using a hindfoot arthrodesis nail (TRIGEN Hindfoot Fusion Nail, Smith & Nephew, Memphis, Tennessee). Surgery was undertaken by a single surgeon (VK) using a standard technique (Figs 2 and 3). During the course of the study the standard distal locking screws were replaced by hydroxyapatite-(HA) coated screws as standard screws had migrated in two patients during the early part of the study. Patients with additional midfoot deformities were treated with simultaneous midfoot fusion using a bolt and/or a locking plate. Correction of the deformity was achieved by resecting a wedge of bone through a single incision on the convex side
of the deformity where possible and stabilised with the hindfoot fusion nail. An extended lateral approach, including a proximal translateral malleolar approach to the ankle and more distally directly over the subtalar joint was used for a varus ankle and hindfoot deformity. A two-incision approach was used for valgus deformities, involving an anteromedial approach to the ankle and a separate lateral approach to the subtalar joint. The residual midfoot deformity was corrected using a separate incision over the apex of the deformity, with the principles of wedge resection and plate and/or intramedullary stabilisation. The concept of a ‘super construct’20 was used for stabilisation of the deformity. This required fixation to be extended beyond the zone of Charcot involvement of the midfoot into the uninvolved first tarso-metatarsal joint to provide a long segment of fixation. Deep tissue samples were sent for microbiological assessment. Minor tightness of the tendo-Achillis often improved following wedge resection. Percutaneous lengthening of the tendo-Achillis was performed using multiple stab wounds if there was a severe contracture. Bone graft substitutes were used as required before closure over a drain. Post-operative wound management was supervised by the multi-disciplinary team. Non weight-bearing was continued for at least three months followed by partial weight-bearing for three more months, guided by the radiological and clinical progression of healing. Full weight-bearing in a removable brace was allowed thereafter, once union was shown on radiographs or CT scans. The THE BONE & JOINT JOURNAL
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Fig. 2a
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Fig. 2b
Fig. 2c a) Pre-operative clinical photograph and radiograph, b) post-operative clinical photographs and c) two weeks post-operative radiograph showing hindfoot nail fusion of the left ankle in a 50-year-old female patient. The arrowhead (a) indicates the side of interest. The patient had additional midfoot fusion using bolt and plate and hallux stabilisation simultaneously. The deformity correction and post-operative healing of a long-term medial malleolar ulcer are illustrated.
Fig. 3a
Fig. 3b
a) Pre- and b) 6-month post-operative radiographs showing bony fusion at 4.6 months in a 62-year-old male patient who presented with a left-sided Charcot foot deformity and multiple ulcers. This patient underwent peroneal angioplasty before proceeding to hindfoot nail arthrodesis.
patients were then allowed to progress to full weight-bearing using well-fitting lace-up shoes or custom-made foot wear. The migration of distal locking screws was measured six months post-operatively in comparison with the immediate post-operative appearance. In order to eliminate the effect of rotation and magnification of two different radiographs, the ratio of the proximal part of the screw to its total length was calculated to enable estimation of the amount of VOL. 97-B, No. 1, JANUARY 2015
migration as a percentage of the total length of the screw. Migration of > 2.0% of the length of the screw was considered to be significant as in control measurements, it was observed that the average error using this method was between 0% and 2% and that a dislodgement of < 2% could therefore not reliably be detected. The outcome measures which were used included the American Academy of Orthopaedic Surgeons Foot and
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Table II. Outcomes of treatment Outcome of treatment
Number, (range/%)
Mean follow-up (mths) Limb salvage (feet) Ulcer healing Return to FWB FWB in custom foot orthoses FWB in off shelf orthoses Wheel chair bound Tibiotalar fusion Radiological fusion Stable fibrous fusion Nonunion Mean time to fusion (mths) FWB, fully weight bearing
25 (8 to 54) 21 (100) 12 of 15 (80) 20 (95) 4 (20) 2 (10) 1 (5) 19 (90) 1 (5) 1 (5) 7.3 (2.2 to 38)
Table III. Patient self-reported outcomes scores (PROMs), before and after surgery PROMs
Before surgery
After surgery
Z-value
p-value
AAOS-FAO EQ-5D-5L SF-36 PCS SF-36 MCS SF-36 physical functioning SF-36 bodily pain* SF-36 social functioning
50.7 0.63 25.2 48.7 25.9 34.3 33.6
65.2 0.67 29.8 48.7 29.2 41.0 39.5
-2.49 -2.52 -2.93 -1.780 -2.539 -2.53 -2.36
0.013 0.012 0.003 0.075 0.011 0.012 0.042
PCS, Physical Component Summary; MCS, Mental Component Summary; AAOS-FAO, American Academy of Orthopaedic Surgeons-Foot and Ankle Outcomes; SF-36, short-form-36 * higher sore is less pain. The Wilcoxon signed-rank test was used to calculate p-values
Ankle Outcomes (AAOS-FAO),21 Short Form (SF)-36 Health Survey22 and the Euroqol EQ-5D-5L23 which were recorded pre- and post-operatively. The following were also recorded: limb salvage, the achievement of full weight-bearing, the healing of ulcers, bony fusion and revision surgery. Statistical analysis. The Wilcoxon signed-rank test was used to examine differences for statistical significance, which was defined as a p-value < 0.05
Results All patients (21 feet) underwent hind foot deformity correction and tibiocalcaneal fusion using the IM hindfoot fusion nail. A total of seven patients (seven feet) underwent simultaneous midfoot fusion which was achieved using a medial column bolt alone in four patients, a bolt augmented by a locking plate in two and a dorsal locking plate alone in one patient. Two patients underwent simultaneous first metatarsophalangeal joint fusion. Two required percutaneous lengthening of the tendo-Achillis. One had a split skin graft at the time of initial surgery. The mean follow-up was 26 months (8 to 54). Limb salvage was achieved in all patients (Table II). Patient satisfaction and function improved as reflected by all three PROMs (Table III). One patient died due to a cerebrovascular accident, four years after surgery. Healing of the ulcer was achieved in 12 of 15 patients (12 of 15 feet) who had ulceration pre-operatively at a median of 8 months
(6 to 13) post-operatively. All but one patient achieved full weight-bearing, with patients wearing well-fitting shoes. Three (four feet) required a custom-made ankle-foot orthosis and two needed a pneumatic walking brace. One patient remained wheel-chair bound. Fusion was achieved radiologically in 19 of 21 feet (90%); one had a stable painless pseuodoarthrosis. One fusion failed to unite. Two patients underwent nail removal due to complications. In one patient, the fixation failed and the nail broke, requiring removal of the nail and revision fixation. The nail was removed in another patient due to a non-healing ulcer over the sole at the site of insertion of the nail. Three reconstructions required dynamisation of the nail by removal of proximal locking screws to enhance fusion. In three of the four feet in which simultaneous midfoot fusion using a bolt alone was undertaken, the bolt migrated, requiring revision using a locking plate. Four of 22 standard distal locking screws (18%), in two patients, migrated by approximately one third of the length of the screw. None of the 34 HA coated locking screws migrated.
Discussion These results show that single-stage reconstuction and internal fixation in patients with severe Charcot ankle and hindfoot deformity can achieve healing of chronic ulcers and independent mobilisation with appropriate THE BONE & JOINT JOURNAL
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supplementary orthoses in most patients. These improvements in outcome were associated with significantly better quality of life as reflected by PROMs after surgery. The rate of major complications following hindfoot nail arthrodesis is significantly higher in patients with diabetic neuroarthopathy.24 Consequently, reconstruction has been limited to a few centres with few reports involving large series. In Charcot feet without chronic ulceration, Dalla Paola et al11 achieved 100% limb salvage and a 77.8% rate of fusion (n = 18). Similarly, a 100% limb salvage and rate of fusion using a longer IM femoral nail was reported in a smaller study including nine patients with Charcot feet without ulcers.25 However, the results of hindfoot nail arthrodesis in Charcot feet with ulcers have been poorer. Caravaggi et al8 reported 45 patients, seven with chronic ulcers, with a rate of limb salvage of 86.7%. Pinzur and Kelikian12 reported a cohort of 21 patients, eight with chronic ulcers, with a rate of limb salvage of 95.2% and a rate of fusion of 90.5 %. With 12 feet (26%) having preoperative ulceration, DeVries et al10 showed a higher rate of amputation (22%) in their cohort of 45 Charcot feet. In contrast we achieved 100% limb salvage in our patients with 71% of feet having chronic ulceration and 52% feet having ulcers at the time of surgery. Improvement in PROMs in our patients suggests that the salvaged limbs had satisfactory function. With our approach, the presence of a pre-operative ulcer does not seem to be a contraindication for using an internal fixation device such as an IM nail for fusion in these patients. The combination of DM, peripheral neuropathy, obesity, impaired renal function and other cardio-vascular comorbidities raises the peri-operative morbidity and mortality.26 These patients characteristically have wounds which heal poorly due to loss of protective sensation and to long-standing DM that increases the risk of peripheral arterial disease and microvascular dysfunction with impaired tissue oxygenation.27 Correction of deformity, meticulous wound management and a pressure offloading regime resulted in a rate of ulcer healing of 80%. All wounds healed initially but ulcers developed later due to prominent metal work in two feet; the wounds healed after removal of metal work. Complications were mostly noted in relation to midfoot fusion using a medial column bolt in patients who underwent simultaneous midfoot reconstruction. However, no further complications occurred following revision to fusion using a locking plate. Although medial column fusion alone has been shown to be successful in a small study (n = 5),28 performing this as a procedure in addition to hindfoot nail fusion in feet with severe deformities at many sites resulted in a high rate of revision in our study. More recently, the use of external ring fixators in patients with CN has become popular as an alternative to IM fixation. Pinzur et al29 reported the largest cohort (n = 178), with a rate of limb salvage of 95.7%. In their study, 45 of 73 patients (62%) who had an ulcer achieved healing after VOL. 97-B, No. 1, JANUARY 2015
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surgery. Fragomon et al30 reported a rate of limb salvage of 95% and a rate of union of 73% using an Ilizarov frame, with one frame revision and four tibial stress fractures in a series of 19 patients. Dalla Paola et al13 and El-Gafary et al31 achieved rates of limb salvage of 89% (n = 45) and 100% (n = 20), respectively. One study compared the use of an IM nail alone to nailing combined with the use of a circular external fixator and concluded the latter may add extra stability to the construct.10 No study has directly compared the results of different surgical techniques, or of reconstruction versus amputation. Our study showed that similar or better results can be obtained in these patients with reconstruction using a hindfoot nail, thereby avoiding the problems associated with external fixation, such as poor compliance, the need for several operations, meticulous long-term pin tract care, and a negative psychological impact.32,33 The durability of fixation following Charcot hindfoot fusion is paramount, as the time to fusion is often > three months and the bone is usually osteopenic. The arthrodesis nail used in this study has threaded distal screw holes to improve engagement and thereby reduce the risk of migration of the screw. Nevertheless, non-HA coated locking screws showed significant migration six months post-operatively. This effect is well known in mechanical engineering as rotational loosening in bolted joints due to cyclic transverse loads.34,35 Factors increasing the threshold of loosening are an increased frictional coefficient, steeper thread lead angle, finer threads, increased preload and the use of adjuncts such as fasteners. In biological tissue, HA coating increases the torque of screws during insertion and extraction compared to standard screws.36 In addition, the potential for bony on-growth on the screws may further increase the self-loosening threshold of distal locking screws. These factors probably contributed to the superior fixation of HA coated screws as there was no migration or osteolysis around these screws. Following reconstruction of a foot in patients with CN, close monitoring and care in a multi-disciplinary team is required to avoid complications in these complex patients. This extensive care is time consuming and expensive and this may serve as an argument for proponents of amputation. However, a cost comparison study of limb salvage (n = 76) versus amputation (n = 17) in patients with CN could not find any difference within the first year.37 A total of nine of our patients were offered amputation elsewhere and were referred to our centre for a further opinion. We acknowledge that there are limitations to this study. The outcome of treatment was not compared with a control group, but a randomised controlled trial in such a diverse and complex group of patients is practically challenging. Although our series involves a small number of patients, with few centres undertaking this approach, the numbers of patients available is limited. A multicentre, prospective, randomised controlled trial would be the best way to shed more light on this approach.
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M. SIEBACHMEYER, K. BODDU, A. BILAL, T. W. HESTER, T. HARDWICK, T. P. FOX, M. EDMONDS, V. KAVARTHAPU
In summary, we report satisfactory outcome following corrective fusion of severe deformities of the ankle and hindfoot in patients with CN treated with a hindfoot intramedullary nail. Most patients achieved healing of an ulcer and independent mobilisation. Complications occurred mostly in patients who underwent simultaneous midfoot fusion using a bolt. Initial results also suggest that HA coating of distal locking screws may achieve better fixation. M. Siebachmeyer: Data collection, Writing and editing the manuscript, Checking the proof. K. Boddu: Writing and editing the manuscript, Checking the proof A. Bilal; Co-author, Data collection. T. W. Hester; Co-author, Data collection. T. Hardwick; Data collection. T. Fox; Data collection. M. Edmonds: Writing and editing the manuscript, Checking the proof. V. Kavarthapu: Writing and editing the manuscript, Checking the proof. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by G. Scott and first proof edited by J. Scott.
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