challenge of treatment calcaneal osteomyelitis: surgical options and outcome of a case series

Introduction

Osteomyelitis represents one of the main and most devastating complication in orthopedics. Calcaneal osteomyelitis (CO) accounts for 3–10% of all bone infections, [1], Sabater-Martos M., Sigmund I.K., Loizou C., McNally M. Surgical treatment and outcomes of calcaneal osteomyelitis in adults: A systematic review. J Bone Jt Infect. 2019;4:146-54. doi: 10.7150/jbji.34452[2], Agrawal A.C., Ojha M.M., Garg D.K., Pandiyarajan E. Calcaneal Osteomyelitis Treated with Antibiotic Mixed Calcium Sulphate Pellets. A Case Report. Journal of Orthopaedic Case Reports 2021 October: 11(10): Page 81-83.[3], Yoohak Kim et al. A Case of Osteomyelitis after Calcaneal Fracture Treated by Antibiotic-Containing Calcium Phosphate Cements. Hindawi, Case Reports in Orthopedics, Volume 2018, Article ID 9321830, 4 pages, https://doi.org/10.1155/2018/9321830[20] Saxon A.J., Verdin C., Nicolosi N. Calcanectomy for the Treatment of Osteomyelitis in a Patient with a Chronic Calcaneal Fracture: A Case Report. The Northern Ohio Foot & Ankle Foundation Journal, 2020, Vol. n°1.. Schildhauer et al. (2000) quantified the calcaneal rate of infections with 11% [3], Yoohak Kim et al. A Case of Osteomyelitis after Calcaneal Fracture Treated by Antibiotic-Containing Calcium Phosphate Cements. Hindawi, Case Reports in Orthopedics, Volume 2018, Article ID 9321830, 4 pages, https://doi.org/10.1155/2018/9321830[4] Schildhauer T.A., Bauer T.W., Josten C., Muhr G. “Open reduction and augmentation of internal fixation with an injectable skeletal cement for the treatment of complex calcaneal fractures,” Journal of Orthopaedic Trauma, 2000. vol. 14, n°5, pp. 309–317.. CO usually happens after trauma, post-surgery, complication of the diabetic foot and through hematogenous spread in children. Overall, Staphylococcus aureus remains the most common causative bacteria in all age groups [2], Agrawal A.C., Ojha M.M., Garg D.K., Pandiyarajan E. Calcaneal Osteomyelitis Treated with Antibiotic Mixed Calcium Sulphate Pellets. A Case Report. Journal of Orthopaedic Case Reports 2021 October: 11(10): Page 81-83.[22] Chen K., Balloch R. Management of calcaneal osteomyelitis. Clin Podiatr Med. Surg. 2010; 27:417-29..

The treatment principal includes early definitive diagnosis by culture, imaging studies, blood parameters, tailored systemic antibiotic coverage, wound irrigation, wide surgical debridement, curettage, partial or total calcaneal resection with or without soft tissue coverage. When it turned into a chronic phase, treatment procedures become more difficult [2], Agrawal A.C., Ojha M.M., Garg D.K., Pandiyarajan E. Calcaneal Osteomyelitis Treated with Antibiotic Mixed Calcium Sulphate Pellets. A Case Report. Journal of Orthopaedic Case Reports 2021 October: 11(10): Page 81-83.[10], Patzakis M.J., Zalavras C.G. “Chronic posttraumatic osteomyelitis and infected nonunion of the tibia: current management concepts,” The Journal of the American Academy of Orthopaedic Surgeons, vol. 13, n°6, pp. 417–427, 2005.[11], Zarutsky E., Rush S.M., Schuberth J.M. “The use of circular wire external fixation in the treatment of salvage ankle arthrodesis,” The Journal of Foot and Ankle Surgery, vol. 44, n°1, pp. 22–31, 2005.[23] McCann M.J., Wells A. Calcaneal osteomyelitis: Current treatment concepts. Int J Low Extrem Wounds 2020; 19:230-5..

The preservation of the calcaneus and a functional foot anatomy is the main target during CO treatment. This is not always possible and depending on the local situation [3] Yoohak Kim et al. A Case of Osteomyelitis after Calcaneal Fracture Treated by Antibiotic-Containing Calcium Phosphate Cements. Hindawi, Case Reports in Orthopedics, Volume 2018, Article ID 9321830, 4 pages, https://doi.org/10.1155/2018/9321830. Surgical treatment of CO currently offers only a handful of curative options including bone debridement, partial or total calcanectomy as well as below-knee amputation [20] Saxon A.J., Verdin C., Nicolosi N. Calcanectomy for the Treatment of Osteomyelitis in a Patient with a Chronic Calcaneal Fracture: A Case Report. The Northern Ohio Foot & Ankle Foundation Journal, 2020, Vol. n°1.. Following major lower extremity amputation US Centers for Disease Control data show a 1-year mortality rate of 30%, a 3-year rate of 50%, and a 5-year rate of 70%, [24], Gangopadhyay P., Scot Malay D. Limb salvage in the setting of calcaneal osteomyelitis and pathologic fracture: A case report with a 15-year follow-up. Foot & Ankle Surgery: Techniques, Reports & Cases 1 (2021) 100023 https://doi.org/10.1016/j.fastrc.2021.100023[25] Centers for Disease Control and Prevention. National diabetes fact sheet: general information and national estimates on diabetes in the United States, 2005. Atlanta, GA: US Dept. of Health and Human Services, Centers for Disease Control and Prevention; 2005.. Avoidance of transtibial and transfemoral amputations is important in regard to minimizing morbidity and mortality [24], Gangopadhyay P., Scot Malay D. Limb salvage in the setting of calcaneal osteomyelitis and pathologic fracture: A case report with a 15-year follow-up. Foot & Ankle Surgery: Techniques, Reports & Cases 1 (2021) 100023 https://doi.org/10.1016/j.fastrc.2021.100023[26] Walsh T.P., Yates B.J. Calcanectomy: avoiding major amputation in the presence of calcaneal osteomyelitis-A case series. The Foot. 2013; 23:130–135. . Case reports advocate the use of partial calcanectomy as a viable alternative to below knee amputation [24] Gangopadhyay P., Scot Malay D. Limb salvage in the setting of calcaneal osteomyelitis and pathologic fracture: A case report with a 15-year follow-up. Foot & Ankle Surgery: Techniques, Reports & Cases 1 (2021) 100023 https://doi.org/10.1016/j.fastrc.2021.100023. According to Lehmann et al. (2021), and Bollinger M., Thordarson D.B. (2002) partial calcanectomy represents an alternative to lower leg amputation in cases of strictly local infection [5], Lehmann S., Murphy R.D., Hodor L. “Partial calcanectomy in the treatment of chronic heel ulceration,” Journal of the American Podiatric Medical Association, 2001,vol. 91, n° 7, pp. 369–372,.[6] Bollinger M., Thordarson D.B. “Partial calcanectomy: an alternative to below knee amputation,” Foot & Ankle International, 2002.vol. 23,n°10, pp. 927–932, . The authors mentioned that partial calcaneal resection may be performed if the inflammatory process involves less than 50% of the heel [7] Baumhauer J.F., Fraga C.J., Gould J.S., Johnson J.E. “Total calcanectomy for the treatment of chronic calcaneal osteomyelitis,” Foot & Ankle International, 1998, vol. 19, n°12, pp. 849–855.. In these circumstances, the sufficient hind foot blood supply seems to be the central problem [8],Smith D.G. “Principles of partial foot amputation in the diabetic,” Foot and Ankle Clinics, 1997, vol. 2, n°1, pp. 171–186,.[9] Weinfeld S.B., Schon L.C. “Amputation of the perimeters of the foot,” Foot and Ankle Clinics, 1999, vol. 4, no. 1, pp. 17–37,. https://doi.org/10.1155/2018/9321830.

However, the reconstruction of the resulting skeletal and soft tissue defects is often complex. In contrast to the more proximal segments of the leg, the availability of soft tissue for the coverage of full-thickness defects with local or regional flaps is limited [12], Baumeister S., Germann G. “Soft tissue coverage of the extremely traumatized foot and ankle,” Foot and Ankle Clinics, vol. 6, n°4, pp. 867–903, 2001.[13] Levin L.S. “Soft tissue coverage options for ankle wounds,” Foot and Ankle Clinics, vol. 6, no. 4, pp. 853–866, 2001.. Reconstruction of skeletal defects can be accomplished with bone grafting [14] Zalavras C.G. Patzakis M.J., Thordarson D.B., Shah S., Sherman R., Holtom P. “Infected fractures of the distal tibial metaphysis and plafond,” Clinical Orthopaedics and Related Research, vol. 427, pp. 57–62, 2004.. However, large defects require complex reconstructive procedures, such as distraction osteogenesis, vascularized bone grafting, or transfer of free flaps [10], Patzakis M.J., Zalavras C.G. “Chronic posttraumatic osteomyelitis and infected nonunion of the tibia: current management concepts,” The Journal of the American Academy of Orthopaedic Surgeons, vol. 13, n°6, pp. 417–427, 2005.[15], Keating J.F., Simpson A.H.R.W., Robinson C.M. “The management of fractures with bone loss,” The Journal of Bone and Joint Surgery British 2005,vol.87-B, n°2, pp. 142–150.[16] Malizos K.N., Zalavras C.G., Soucacos P.N., Beris A.E., Urbaniak J.R. “Free vascularized fibular grafts for reconstruction of skeletal defects,” The Journal of the American Academy of Orthopaedic Surgeons, 2004, vol. 12, n°5, pp. 360–369..

In this paper the technique and outcome of a case series of CO with the concomitant use of bone and soft tissue approaches for patients diagnosed with CO are described.

Materials & methods

Twenty-five consecutive patients with osteomyelitis and open fractures of the calcaneus were included between 2005 and 2018. All patients were admitted to the Bone Infection Unit at our hospital under the responsibility of an orthopaedic surgeon (specializing in foot ankle surgery and bone infection surgery) who performed all operations. Patients demographics, cause of CO, previous treatment and comorbidities are summarized in table 1. Patients presented with pain (100%), swelling (100%) and purulent discharge from heels (80%). The most common causes of CO were fracture-related infection (14 patients), acute hematogenous osteomyelitis (6 patients), penetrating soft tissue trauma (2 patients) and complications after surgery (3 patients). All patients had received previous antibiotics. Sixteen patients (64%) had already undergone previous operation elsewhere. Blood parameters for WBC, ESR and CRP were elevated. Radiographs of the calcaneus showed destruction in the lesion with sclerosis of the bone tissue around the lesion. Some patients had total sclerosis of the calcaneus. Chronic CO had been diagnosed with clinical and radiograph signs of osteomyelitis for minimum 2 months, and one of the following criteria: sinus, abscess, intraoperative pus, or positive microbiological cultures from deep surgical samples.

After diagnosing CO all patients were planned for surgery under systemic antibiotic coverage. Postoperative antibiotics began empirical until appropriate bacterial culture and sensitivity results were available. The calcaneus was approached from lateral with an L shaped incision which allows good access to the infected bone and has the advantages of preserving the Achilles tendon attachment, the weight bearing surface of the calcaneus, and the overlying soft tissue. Any sinus tracts were excised and the subcutaneous and deeper soft tissues were debrided until healthy bleeding tissue planes. Thorough bone debridement or partial calcanectomy was performed and the infected bone was sent for cultures. The amount of bone debridement and excision was based on preoperative radiographs and until healthy bleeding bone remained, using curettes, cutters and osteotomes. The wound was closed either with local tissues or with one of the methods of plastic surgery. Intravenous antibiotics were continued for 1 week postoperatively followed by oral antibiotics for 1 month. All patients were seen regularly for the first 2 years after the operation, at 6 weeks, 3 months, 6 months, 1 year, and 2 years.

Results

Cultures taken from the deeper aspect of the wound are summarized in Diagram 1. They included facultative anaerobe Gram-positive cocci: Staphylococcus aureus (31%), Staphylococcus epidermidis (7%), Streptococcus pyogenes (3.5%), Streptococcus agalactiae (7%); facultative anaerobe Gram-negative bacillus: Enterobactericeae family: Escherichia coli (10%), Proteus mirabilis (3.5%); Proteus vulgaris (7%); anaerobe nonfermentive Gram-negative bacillus: Pseudomonas aeruginosa (14%); form endosymbiotic fungi: Candida albicans (17%). All of the cultured microorganisms were sensitive to vancomycin and/or gentamycin (Diag.1).

All patients underwent surgery and type of bone and soft tissue management are summarized in (Table 2).

Outcomes, complications, and clinical function are summarized in table 3. Infection was successfully eradicated in 22 patients at 1-year follow-up. Wounds healed by primary intention in 18 (72%) patients. Postoperative complications occurred in 9 patients (36 %) including wound leakage in 4 patients and recurrence of the osteomyelitis process occurred in 3 patients. All of them underwent successful reoperations with necrectomy. Wounds in the plantar surface of the heel developed in 2 patients after 6 months and was not associated with recurrent osteomyelitis. After conservative treatment they have healed.

Patients stayed in the clinic for 2-4 weeks. After that, patients began to gradually load the leg for 20-30 days followed by full weight bearing. Most patients (88%) were able to walk unaided, and 3 (12 %) needed crutches. 17 (68%) had a foot that comfortably fit into a regular shoe. Ordinary shoes with an insole were worn by 5 patients (12.5%), 3 patients wore a custom-made shoe (7.5%). Mild weight bearing pain was in 3 patients, 22 reported being pain free (Table 3).

Clinical case

A 59-year-old male patient was admitted with pain in the right calcaneus. More than 2 years ago, he had an open fracture of the right calcaneus with wound healing problems and a fistula one month after surgery.

Diagnosis: chronic post-traumatic osteomyelitis of the right calcaneus.

Operation: Longitudinal osteotomy of the right calcaneus, intralesional resection to healthy tissues. Primary wound healing and after 2 months full weight bearing. x-rays at 6 months show a healed bony lesion and no complaints (Figure 1).

Discussion

Osteomyelitis of the calcaneus is a challenge for the patient and the surgeon. Generally, the goal of treatment includes eradication of infected bone, ensuring skeletal stability, adequate soft tissue coverage and preservation of function of the foot. Surgical management of CO includes local curettage or partial calcanectomy or total calcanectomy. In more severe cases of extensive calcaneal involvement, limited soft tissue coverage creates a challenge for the surgeon to allow for primary closure. Excision of devascularized infected bone risks destroying the weight bearing plantar cortex, detaching the Achilles tendon and disrupting the hindfoot complex. Moreover, in cases of osteomyelitis, the overlying plantar fat pad and skin are often compromised and limit soft tissue closure. Often below knee amputation has been recommended in these cases [20], Saxon A.J., Verdin C., Nicolosi N. Calcanectomy for the Treatment of Osteomyelitis in a Patient with a Chronic Calcaneal Fracture: A Case Report. The Northern Ohio Foot & Ankle Foundation Journal, 2020, Vol. n°1.[31], Kendal A., Loizou C., Down B., McNally M. Long-term follow-up of complex calcaneal osteomyelitis treated with modified Gaenslen approach. Foot & Ankle Orthopaedics 2022, Vol. 7(4) 1–9.[36], Kendal A.R., Ferguson J., Wong T.H.N., Atkins B.L., McNally M. Osteomyelitis - symptoms, diagnosis and treatment. BMJ Best Practice Update. BMJ Best Pract. April 7, 2021.[37], Huang K., Guo Q.F., Zhu Y.S. The epidemiology and clinical features of calcaneus osteomyelitis following calcaneus fracture: a retrospective study of 127 cases. Ann Palliat Med. 2021; 10(3):3154-3161. doi: 10.21037/apm-21-208 [38], Iacobucci G. One in 10 UK adults could have diabetes by 2030, warns charity. BMJ. 2021; 375:n2453.[40], Jiang N., Zhao X.Q., Wang L., Lin Q.R., Hu Y.J., Yu B. Single-stage debridement with implantation of antibiotic-loaded calcium sulphate in 34 cases of localized calcaneal osteomyelitis. Acta Orthopaedica 2020; 91 (3): 353–359.[41] Mooney M L, Haidet K, Liu J, Ebraheim N A. Hematogenous calcaneal osteomyelitis in children. Foot Ankle Spec 2017; 10(1): 63-8. .

Only 3 (12.5%) patients in our study had a recurrence of bone infection which was similar to those of previous studies [40], Jiang N., Zhao X.Q., Wang L., Lin Q.R., Hu Y.J., Yu B. Single-stage debridement with implantation of antibiotic-loaded calcium sulphate in 34 cases of localized calcaneal osteomyelitis. Acta Orthopaedica 2020; 91 (3): 353–359.[42], Ferguson J.Y., Dudareva M., Riley N.D., Stubbs D., Atkins B.L., McNally M.A. The use of a biodegradable antibiotic-loaded calcium sulphate carrier containing tobramycin for the treatment of chronic osteomyelitis: a series of 195 cases. Bone Joint J 2014; 96-B (6): 829-36.[43], Ferguson J., Diefenbeck M., McNally M. Ceramic biocomposites as biodegradable antibiotic carriers in the treatment of bone infections. J Bone Jt Infect 2017; 2(1): 38-51.[44] Luo S., Jiang T., Yang Y., Yang X., Zhao J. Combination therapy with vancomycin-loaded calcium sulfate and vancomycin-loaded PMMA in the treatment of chronic osteomyelitis. BMC Musculoskelet Disord 2016; 17(1): 502.. Complications occurred in 9 cases (36%) including local ulcer, aseptic wound leakage and partial skin necrosis which needed 3 reoperations. Multiple further cohort series of partial, subtotal, and total calcanectomies have been published with varying results. One systematic review reports 80% healing rates, with better results occurring with partial rather than total calcanectomies [21], Yammine K., El-Alam A., Assi C. (2021) Outcomes of partial and total calcanectomies for the treatment of diabetic heel ulcers complicated with osteomyelitis. A systematic review and meta-analysis. Foot Ankle Surg 2021;27(6): 598–605. doi: 10.1016/j.fas.2020.07.014.[27], Wokhlu A., Vasukutty N. Partial calcanectomy with antibiotic biocomposite injection for diabetes patients with heel ulcers and calcaneal osteomyelitis: a single-stage treatment. The Diabetic Foot Journal 2021, Vol 24 No 3, p. 34-37.[31] Kendal A., Loizou C., Down B., McNally M. Long-term follow-up of complex calcaneal osteomyelitis treated with modified Gaenslen approach. Foot & Ankle Orthopaedics 2022, Vol. 7(4) 1–9.. Another systematic review found that 85% of patients receiving a partial calcanectomy maintained their mobility levels [31], Kendal A., Loizou C., Down B., McNally M. Long-term follow-up of complex calcaneal osteomyelitis treated with modified Gaenslen approach. Foot & Ankle Orthopaedics 2022, Vol. 7(4) 1–9.[39] Schade V.L. Partial or total calcanectomy as an alternative to below-the-knee amputation for limb salvage: a systematic review. J Am Podiatr Med Assoc. 2012; 102(5):396-405. doi: 10.7547/1020396.. Partial calcanectomy is a relatively simple procedure for chronic heel ulcers with limited calcaneal involvement. The amount of soft tissue compromise may allow for primary closure following partial calcanectomy [20], Saxon A.J., Verdin C., Nicolosi N. Calcanectomy for the Treatment of Osteomyelitis in a Patient with a Chronic Calcaneal Fracture: A Case Report. The Northern Ohio Foot & Ankle Foundation Journal, 2020, Vol. n°1.[31], Kendal A., Loizou C., Down B., McNally M. Long-term follow-up of complex calcaneal osteomyelitis treated with modified Gaenslen approach. Foot & Ankle Orthopaedics 2022, Vol. 7(4) 1–9.[36] Kendal A.R., Ferguson J., Wong T.H.N., Atkins B.L., McNally M. Osteomyelitis - symptoms, diagnosis and treatment. BMJ Best Practice Update. BMJ Best Pract. April 7, 2021..

Whether bone infection relapses after treatment is influenced by multiple factors, such as surgical strategies, pathogen species and virulence and finally, host immune status. The goal of operations is to remove all the devitalized infected tissues, leaving behind healthy vascularized bone. It is reasonable to understand that the protocols for CO treatment include partial and total calcanectomy, or even below-knee amputation. Although infection can be eradicated following such radical surgeries, the foot function may be more or less impaired [40], Jiang N., Zhao X.Q., Wang L., Lin Q.R., Hu Y.J., Yu B. Single-stage debridement with implantation of antibiotic-loaded calcium sulphate in 34 cases of localized calcaneal osteomyelitis. Acta Orthopaedica 2020; 91 (3): 353–359.[45], Metsemakers W.J., Kuehl R., Moriarty T.F., Richards R.G., Verhofstad M.H. J., Borens O., Kates S., Morgenstern M. Infection after fracture fixation: current surgical and microbiological concepts. Injury 2018a; 49(3): 511-22.[46] Waibel F.W.A., Klammer A., Gotschi T., Uckay I., Boni T., Berli M.C. Outcome after surgical treatment of calcaneal osteomyelitis. Foot Ankle Int 2019; 40(5): 562-7. .

If a primary wound closure is not possible it can be achieved by various plastic procedures including free muscle flaps (serratus anterior, gracilis), or local flaps (rotational flaps, abductor digiti minimi flap, neurocutaneous or fasciomusculocutaneous flaps). Skin grafting with a rotational flap using local tissues (Qarris and Saad method) was performed in 4 patients, wounds in 2 patients were closed with free split skin flaps. The reviewed studies showed no difference in the reinfection rate and failure rate of the flaps. However, the choice of soft tissue coverage should be based on the location and size of the soft tissue defect. Direct closure with the adjacent normal skin is preferable, but small defects may be reliably covered by local pedicle flaps [1], Sabater-Martos M., Sigmund I.K., Loizou C., McNally M. Surgical treatment and outcomes of calcaneal osteomyelitis in adults: A systematic review. J Bone Jt Infect. 2019;4:146-54. doi: 10.7150/jbji.34452[47] Boffeli T.J., Collier R.C. Near total calcanectomy with rotational flap closure of large decubitus heel ulcerations complicated by calcaneal osteomyelitis. J Foot Ankle Surg. 2013;52(1):107-112.. Disadvantages of free vascularized flaps are the need of microsurgery, long operation time, and prolonged hospital stay combined with higher costs. They are also usually insensate, producing a later risk of pressure ulceration. Regardless of which coverage is used, the applied procedure should guarantee an improved bone vascularization and a good dead space management to avoid haematoma formation [1], Sabater-Martos M., Sigmund I.K., Loizou C., McNally M. Surgical treatment and outcomes of calcaneal osteomyelitis in adults: A systematic review. J Bone Jt Infect. 2019;4:146-54. doi: 10.7150/jbji.34452[48] Attinger C., Cooper P. Soft tissue reconstruction for calcaneal fractures or osteomyelitis. Orthop Clin North Am. 2001;32(1):135–170..

Despite the presence of various microorganisms in the formation of CO, gram-positive bacteria play a major role. In our study staphylococcus strains were the more common with 38 %. The majority were coagulasopositive Staphylococcus aureus with 31% which might occur in single and associative forms. Similar results were observed by many authors [2], Agrawal A.C., Ojha M.M., Garg D.K., Pandiyarajan E. Calcaneal Osteomyelitis Treated with Antibiotic Mixed Calcium Sulphate Pellets. A Case Report. Journal of Orthopaedic Case Reports 2021 October: 11(10): Page 81-83.[22], Chen K., Balloch R. Management of calcaneal osteomyelitis. Clin Podiatr Med. Surg. 2010; 27:417-29.[31], Kendal A., Loizou C., Down B., McNally M. Long-term follow-up of complex calcaneal osteomyelitis treated with modified Gaenslen approach. Foot & Ankle Orthopaedics 2022, Vol. 7(4) 1–9.[32] Aliyev H., Rasulova G., Ali-Zade Ch., Benzakour T., Romano C.L., Drago L. Septic Arthritis of the Knee Joint. A 5-year Retrospective microbiology investigation. MO-Journal N°18 – July/August 2022. https://mo-journal.com/posts/septic-arthritis-of-the-knee-joint-in-azerbaijan-a-5-year-retrospective-microbiological-investigation-1787.

Candida albicans were observed in 17 % which needed long term AB therapy. Patients without infection eradication may be caused by ineffective antibiotic therapy, difficulties in the surgical treatment and adverse effects. Other authors observed similar results [32], Aliyev H., Rasulova G., Ali-Zade Ch., Benzakour T., Romano C.L., Drago L. Septic Arthritis of the Knee Joint. A 5-year Retrospective microbiology investigation. MO-Journal N°18 – July/August 2022. https://mo-journal.com/posts/septic-arthritis-of-the-knee-joint-in-azerbaijan-a-5-year-retrospective-microbiological-investigation-1787[33], Khudayberganova Sh.A., Murodov T.R., Khodzhaev K.Sh., Yusupova S.I., Tuyunbayeva L.Sh. Significance of microflora monitoring in a surgical hospital. Wounds and wound infections. Materials of the I International Congress. Moscow, 2012, pp. 341-342.[34], Fraimow H.S., Tsigrelis C. Antimicrobial resistance in the intensive care unit: mechanisms, epidemiology, and management of specific resistant pathogens. Critical care clinics 2011, Vol. 27, n°1, pp. 163–205.[35] Magiorakos A.P., et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clinical microbiology and infection: the official publication of the European Society of Clinical Microbiology and Infectious Diseases 2012, Vol. 18, n°3. pp. 268–281..

Seven pediatric patients (mean age 10.3 years, range 5-16) with chronic CO were treated with trepanation of the calcaneus with intralesional resection from the lateral incision.

A recurrence of the osteomyelitic process was observed in 1 patient. He underwent another successful necrectomy. Osteomyelitis in children is a potentially dangerous disease that requires early diagnosis and treatment in order to prevent the spread of infection to nearby joints, bone growth disorders and reduced quality of life [17], Buonsenso D., Pata D., Masiello E., Salerno G., Valentini P. Calcaneal Osteomyelitis with Persisting Negative X-Rays and Blood Tests. Journal of Case Reports: Clinical & Medical. 2019; 2(3):137.[19] Rasool M.N. Hematogenous osteomyelitis of the calcaneus in children. J Pediatr Orthop. 2011; 21: 738–743.. Nevertheless, acute osteomyelitis is not always easy to recognize since bone pain without systemic signs and symptoms, negative imaging and blood tests may confuse the clinician [18] Jaakkola J., Kehl D. Hematogenous calcaneal osteomyelitis in children. J Pediatr Orthop. 1999; 19: 699–704.. This is especially true when small bones, like the calcaneus, are involved. In this case, signs and symptoms may be even more subtle. Therefore, clinical experience and high index of suspicion are necessary for the emergency pediatrician to recognize and promptly treat these conditions [17] Buonsenso D., Pata D., Masiello E., Salerno G., Valentini P. Calcaneal Osteomyelitis with Persisting Negative X-Rays and Blood Tests. Journal of Case Reports: Clinical & Medical. 2019; 2(3):137..

Conclusion

Chronic osteomyelitis of the calcaneus is a disease that threatens the limb. Treatment of CO can be complex due to the poor soft tissue coverage and the nature of the stress on the calcaneus. CO is difficult to manage and requires a multidisciplinary approach involving orthopaedic surgeons, plastic surgeons and infectious diseases physicians. More than 30% of microbiological data showed the presence of staphylococcus aureus, which must be taken into account in antibiotic therapy at the beginning of treatment. Our results also show that using a single-stage partial resection of calcaneum with primary closure of wound is a viable and useful technique in managing CO.