jkfas Journal of Korean Foot and Ankle Society J Korean Foot Ankle Soc 1738-3757 2288-8551 Korean Foot and Ankle Society 10.14193/jkfas.2019.23.2.58 jkfas-23-58 Original Article Risk Factors for the Treatment Failure of Antibiotic-Loaded Cement Spacer Insertion in Diabetic Foot Infection ParkSe-Jin SongSeungcheol Department of Orthopedic Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea Corresponding Author: Seungcheol Song Department of Orthopedic Surgery, Kangbuk Samsung Hospital, 29 Saemunan-ro, Jongno-gu, Seoul 03181, Korea Tel: 82-2-2001-2168, Fax: 82-2-2001-2176, E-mail: s3g1@naver.com ORCID: https://orcid.org/0000-0002-1841-6683 12019 1412019 23 2 58 66 22042019 28052019 07062019 Copyright © 2019 Korean Foot and Ankle Society 2019 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose:

To evaluate the efficacy of antibiotic-loaded cement spacers (ALCSs) for the treatment of diabetic foot infections with osteomyelitis as a salvage procedure and to analyze the risk factors of treatment failure.

 Materials and Methods:

This study reviewed retrospectively 39 cases of diabetic foot infections with osteomyelitis who underwent surgical treatment from 2009 to 2017. The mean age and follow-up period were 62±13 years and 19.2±23.3 months, respectively. Wounds were graded using the Wagner and Strauss classification. X-ray, magnetic resonance imaging (or bone scan) and deep tissue cultures were taken preoperatively to diagnose osteomyelitis. The ankle-brachial index, toe-brachial index (TBI), and current perception threshold were checked. Lower extremity angiography was performed and if necessary, percutaneous transluminal angioplasty was conducted preoperatively. As a surgical treatment, meticulous debridement, bone curettage, and ALCS placement were employed in all cases. Between six and eight weeks after surgery, ALCS removal and autogenous iliac bone graft were performed. The treatment was considered successful if the wounds had healed completely within three months without signs of infection and no additional amputation within six months.

 Results:

The treatment success rate was 82.1% (n=32); 12.8% (n=5) required additional amputation and 5.1% (n=2) showed delayed wound healing. Bacterial growth was confirmed in 82.1% (n=32) with methicillin-resistant Staphylococcus aureus being the most commonly identified strain (23.1%, n=9). The lesions were divided anatomically into four groups; the largest number was the toes: (1) toes (41.0%, n=16), (2) metatarsals (35.9%, n=14), (3) midfoot (5.1%, n=2), and (4) hindfoot (17.9%, n=7). A significant difference in the Strauss wound score and TBI was observed between the treatment success group and failure group.

 Conclusion:

The insertion of ALCSs can be a useful treatment option in diabetic foot infections with osteomyelitis. Low scores in the Strauss classification and low TBI are risk factors of treatment failure.

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Right foot anteroposterior (A) and lateral (B) radiographs show mild osteolytic lesion on the 1st distal phalanx. T2-weighted axial magnetic resonance imaging (C) shows hypersignal intensity on the 1st distal phalanx and suspicious of abscess formation around it, compatible with osteomyelitis.

Right 1st toe anteroposterior (A) and lateral (B) radiographs after debridement, bone curettage and antibiotic cement spacer insertion.

Right 1st toe anteroposterior (A) and lateral (B) radiographs after antibiotic cement spacer removal and autogenous iliac bone graft.

Right 1st toe anteroposterior (A) and lateral (B) radiographs after 4 months of antibiotic cement spacer removal and autogenous iliac bone graft. The 1st distal phalanx healed nearly as normal, and we could prevent amputation.

Strauss Wound Classification Scoring System

Criteria* 2 points 1 point 0 point
Appearance (wound base) Red Yellow or withe Black
Size Thumb tip or smaller Between Thumb tip and fist Larger than fist
Depth (maximum depth of probe) Skin or subcutaneous Muscle or tendon Bone or joint
Infection (bioburden) Colonized Cellulitis Septic†
Perfusion Palpable pulses Biphasic or triphasic dopplerable pulses (cool, pale or dusky, capillary refill 2~5 sec) Monophasic or imperceptible pulses (cold, black/cyanotic/purplish, capillary refill >5 sec)

Healthy wound: 7.5~10 points, Problem wound: 3.5~7 points, Futile wound: 0~3 points.

* Half points used for mixed or intermediate findings,

Findings associated with sepsis include unstable blood sugars, leukocytosis, positive blood cultures, fever, and chills.

Current Perception Threshold (CPT) by Neurometer

Grade* Sensory classification
12 Completely anesthetic
9.9 Severe hypoesthesia
8.82 Moderate hypoesthesia
7.74 Mild hypoesthesia
6.62 Moderate hyperesthesia
5.54 Mid hyperesthesia
4.82 Mid dysfunction
3.9 Very mild dysfunction
2.78 Extremely mild dysfunction
1.66 Slight dysfunction
0 No abnormal measures

11 grades, 1st toe examed.

Summary of Patient Data Showing Successful Treatment Outcome

No. Age (yr) Sex FU (mo) Location Date of ALCS insertion Date of ALCS removal Interval (d) Pathogens cultured Wagner wound grade Strauss wound score ABI TBI CPT
1 37 Female 6.1 Lt. 5th toe MP&DP 2010-04-01 2010-05-13 42 MSSA 3 5 1.09 0.91 12
2 63 Male 6.2 Lt. 5th toe PP-DP 2017-02-20 2017-03-24 32 MSSA 3 5 1.07 0.59 9.9
3 73 Male 6.4 Rt. navicular, talus, calcaneus 2016-10-15 - - Citrobacter koseri 4 4.5 0.9 0.72 7.37
4 77 Male 12.0 Rt. 2nd toe DP 2016-12-09 2017-01-20 42 MRSA 4 6 0.78 0.49 12
5 39 Male 90.6 Rt. 1st toe PP-DP 2010-04-08 2010-05-20 42 No growth 3 5.5 1.18 0.77 12
6 61 Female 6.1 Rt. 1st toe PP-DP 2010-04-07 2010-10-07 71 MRSA 4 5 1.00 0.69 9.9
7 61 Female 9.7 Rt. 2nd toe PP-DP 2010-11-08 2010-12-30 52 Streptococcus agalactiae 3 5 0.99 0.66 10.9
8 74 Male 6.0 Rt. 1st toe DP 2015-04-20 - - No growth 4 5.5 1.08 0.59 7.3
9 52 Male 25.6 Rt. 1st metatarsal 2010-11-17 2010-12-15 28 MSSA 3 5 0.84 0.39 9.82
10 68 Male 6.3 Lt. 5th metatarsal 2016-11-15 2017-01-02 48 MSSA 3 5 0.95 0.54 12
11 47 Female 105.7 Lt. 1,2,3rd metatarsal 2009-03-19 2009-04-10 22 MSSA 3 5 1.15 0.62 11.5
12 80 Female 6.1 Rt. 1st toe DP 2015-03-11 2015-05-06 56 S. agalactiae 4 6 1.02 0.65 12
13 51 Male 26.6 Lt. 5th toe PP-DP 2012-01-27 2012-03-16 49 MSSA 4 5.5 1.22 0.72 10.9
14 61 Male 8.0 Rt. 1st toe PP-DP 2010-04-29 2010-06-17 49 MRSA 3 5.5 1.13 0.80 12
15 78 Male 7.0 Lt. 1st metatarsal-DP 2015-05-11 2015-07-01 51 No growth 3 5.5 0.54 0.74 10.9
16 59 Male 8.7 Rt. Calcaneus 2017-03-22 2017-05-16 55 Proteus vulgaris, Streptococcus equisimilis 3 4.5 0.98 0.82 12
17 73 Male 8.0 Lt. 5th metatarsal-DP 2010-07-26 2010-09-13 49 S. agalactiae 3 5 0.85 0.67 12
18 39 Male 6.5 Rt. 4th metatarsal 2011-03-04 2011-05-20 77 No growth 4 5 0.87 0.42 12
19 78 Male 14.5 Rt. Calcaneus 2015-01-28 2015-03-25 56 MRSA 3 5 1.02 0.55 9.9
20 70 Female 6.3 Lt. 1st toe PP-DP 2011-10-14 2011-12-10 57 Staphylococcus epidermidis 4 4.5 1.06 0.68 7.3
21 65 Male 17.5 Lt. 1st∼4th metatarsal 2015-03-25 2015-04-10 16 C. koseri, S. equisimilis 3 4.5 1.18 0.74 12
22 49 Male 8.1 Rt. 1st metatarsal-DP 2012-03-23 2012-05-26 64 Enterococcus faecalis, Pseudomonas aeruginosa 3 5 1.07 0.89 10.9
23 64 Male 34.7 Rt. 5th metatarsal-cuboid 2011-01-21 2011-03-11 49 MRSA 3 5 1.05 0.84 9.9
24 49 Female 12.7 Lt. 4th metatarsal-DP 2015-12-23 2016-02-24 63 MRSA 3 5.5 1.02 0.96 10.9
25 58 Male 28.4 Rt. 1st metatarsal-navicular 2010-05-27 2010-07-15 49 E. faecalis 3 5 1.1 0.36 9.78
26 76 Female 6.0 Lt. calcaneus 2017-11-29 2017-12-18 19 MRSA 3 4.5 1.14 0.42 10.9
27 51 Male 7.4 Rt. calcaneus 2016-03-23 2016-05-16 54 MRSA 3 5 1.12 0.75 12
28 73 Female 9.6 Lt. 1st toe PP-DP 2017-08-14 2017-09-25 42 No growth 3 5 1.04 0.91 7.3
29 79 Male 46.0 Lt. 5th toe-metatarsal 2009-04-13 2009-05-15 32 P. aeruginosa 4 5 1.24 0.77 9.9
30 65 Female 8.4 Lt. 5th metatarsal 2016-04-06 2016-05-04 28 S. agalactiae, S. equisimilis 3 5.5 0.59 0.42 12
31 49 Male 6.1 Rt. 2nd∼4th metatarsal 2017-04-08 2017-05-15 37 E. faecalis, MSSA 3 5 0.81 0.58 10.9
32 86 Female 46.7 Lt. 5th metatarsal 2013-10-11 2013-11-21 41 No growth 3 6 1.08 0.84 12

FU: follow-up, ALCS: antibiotic-loaded cement spacers, Interval: interval to secondary surgery, ABI: ankle-brachial index, TBI: Toe-brachial index, CPT: current perception threshold, Rt.: right, Lt.: left, MP: middle phalanx, DP: distal phalanx, PP: proximal phalanx, MSSA: Methicillin-sensitive Staphylococcus aureus, MRSA: Methicillin-resistant Staphylococcus aureus.

Summary of Patient Data Showing Non-Successful Treatment Outcome

No. Age (yr) Sex Location Date of ALCS insertion Date of secondary amputation Interval (wk) Pathogens cultured Wagner wound grade Strauss wound scores ABI TBI CPT
1 65 Male Lt. 1st toe PP-DP 2017-01-16 2017-02-01 2.3 Enterococcus faecalis 4 2.5 0.8 0.35 9.9
2 75 Male Lt. 3rd∼5th metatarsal l 2010-10-25 2011-02-10 15.4 No growth 3 3 0.97 0.23 12
3 62 Male Lt. 1st toe PP-DP 2016-11-02 2017-01-26 12.1 Citrobacter freundii, Enterobacter cloacae 3 3 1.2 0.65 9.9
4 63 Female Lt. 1st toe-calcaneus 2017-06-18 2017-06-21 0.4 E. faecalis, Streptococcus mitis/Streptococcus o oralis 4 2.5 0.7 0.47 12
5 39 Male Rt. 1st toe PP-DP 2009-04-10 2009-08-02 16.3 Streptococcus agalactiae 3 3 1.08 0.64 12
6 53 Male Rt. 1st toe PP-DP 2010-07-14 - - E. faecalis 3 3 1.1 0.68 12
7 40 Male Lt. calcaneus 2010-05-12 - - MRSA 4 3 0.99 0.61 11.5

ALCS: antibiotic-loaded cement spacers, Interval: interval to secondary surgery, ABI: ankle-brachial index, TBI: Toe-brachial index, CPT: current perception threshold, Lt.: left, PP: proximal phalanx, DP: distal phalanx, Rt.: right, MRSA: Methicillin-resistant Staphylococcus aureus.

Distribution of Lesions by Location

Location Number of patients (%)
Toes 16 (41.0)
Metatarsals 14 (35.9)
Midfoot 2 (5.1)
Hindfoot 7 (17.9)
Total 39 (100)

Comparing between Successful Group and Non-Successful Group

Variable Successful group (n=32) Non-successful group (n=7) p-value*
Age (yr) 62.66+13.14 56.71+12.41 0.398
Wagner wound grade 3.28+0.45 3.43+0.49 0.554
Strauss wound score 5.13+0.41 2.86+0.23 <0.01
ABI 1.01+0.16 0.98+0.16 0.654
TBI 0.67+0.16 0.52+0.16 0.040
Neurometer 10.69+1.52 11.33+0.92 0.359

Values are presented as mean+standard deviation.

ABI: ankle-brachial index, TBI: toe-brachial index.

* Mann-Whitney U test.