Risk factors for failure of transmetatarsal amputation in diabetic patients: a cohort study

INTRODUCTION

This study analysed the factors affecting wound healing of a transmetatarsal amputation (TMA) in patients with diabetes.

MATERIALS AND METHODS

Twenty-one patients who failed a TMA and were revised to transtibial amputation (TTA) within the first year were compared with a matched cohort of 21 successful TMA's. The factors compared included demographics, systemic issues, and local conditions in the foot. Chi-square comparisons were used for group data, and Analysis of Variance (ANOVA) for numeric data.

RESULTS

Blood glucose control as measured by HbA1c was the most important single factor predicting the success of TMA. Need for debridement after TMA was also found to be a significant predictor of failure of TMA. There was a trend towards duration of ulcer prior to TMA and smoking being significant. All other variables, including vascular status or renal failure were not significantly different between the two groups.

CONCLUSION

The primary factor determining the success of a TMA was the quality of glucose control. The results of this study can be extrapolated to diabetic patients undergoing other types of surgery, with preoperative diabetic control as measured by HbA1c being an important determinant of the outcome of surgery. As a result of this study we currently do not perform any elective, trauma or emergency surgery on diabetic patients with an HbA1c of over 8 unless the need for surgery is to save life or limb.

Outcome of transmetatarsal amputations in diabetics using antibiotic beads

BACKGROUND

Diabetic patients with transmetatarsal amputation (TMA) for chronic forefoot ulceration or necrosis are at high risk for postoperative skin breakdown and subsequent amputation. Locally applied antibiotics may reduce the revision rate and improve the outcome.

MATERIAL AND METHODS

In a retrospective comparative study, 60 diabetic patients (65 feet) with forefoot ulceration or necrosis were treated with TMA by three surgeons in three hospitals. In the "beads group'' (46 patients, 49 feet) TMA was combined with local application of bioabsorbable, tobramycin impregnated calcium sulphate beads (OsteoSet-T beads, Wright Medical, Memphis, TN) as a single-stage procedure. The remaining 16 patients had transmetatarsal amputation without beads at the surgeon's discretion and acted as a control group. For all patients, time to healing, length of hospital stay, number of revisions for wound breakdown and conversions to a higher-level amputation were retrospectively reviewed. Of the 60 patients 17 had died and three were lost to followup, leaving 40 patients available for latest followup at 29 months. The Foot & Ankle Outcome Score, Foot Function index, SF-36, and Comorbidity score were recorded.

RESULTS

The revision rate for wound breakdown after TMA was 8.2% (4/49) in the beads group, and 25% (4/16) in the control group (p<0.05). At latest followup, 27% (13/49) in the beads group, and 25% (4/16) in the control group had to be converted to transtibial amputation. Patients in the beads group scored worse for activities of daily living in the FAOS and SF-36 (p < 0.05), and demonstrated more health problems in the Comorbidity scores (not significant), indicating sicker individuals in the beads group.

CONCLUSION

Bioabsorbable calcium sulphate antibiotic beads may be a useful addition for TMA for patients with non-healing diabetic ulcerations of the forefoot. The single-stage procedure could have a significant impact on the management of diabetic forefoot ulcerations by preventing additional hospital stays, improving the patient's quality of life and minimizing cost.

Survey of tourniquet use in orthopaedic foot and ankle surgery

BACKGROUND

Tourniquet technique varies among foot and ankle surgeons, and to establish a standard practice guideline the current standard of care should be examined.

METHODS

One hundred and forty responses were received after 253 surveys were mailed to American Orthopaedic Foot and Ankle Society (AOFAS) members, concerning type of tourniquets, location, and pressures used.

RESULTS

Cuff pressures most commonly used were 301 to 350 mmHg for thigh cuffs (49% of thigh cuff users) and 201 to 250 mmHG for calf and ankle cuffs (52% of calf cuff users, 66% of ankle cuff users). A substantial number of foot and ankle surgeons who use calf and ankle cuffs frequently use pressures above 250 mmHg (41% of calf cuff users, 19% of ankle cuff users). Only 9% use limb occlusion pressure when determining cuff pressure.

CONCLUSION

Based on the existing evidence-based literature these pressures may be higher than necessary for many patients, and increased adoption of optimal pressure setting techniques as reported in the literature may help reduce tourniquet pressures used and risk of tourniquet injury. Respondents reported experiencing or hearing reports of breakthrough bleeding, nerve injury, and skin injuries under the cuff.

Survey of tourniquet use in podiatric surgery

Tourniquet use in foot and ankle surgery is common practice; however, the technique varies among foot and ankle surgeons and there are no standard guidelines. To analyze trends in foot and ankle tourniquet use, the authors conducted an e-mail survey. One thousand six hundred sixty-five foot and ankle surgeons were sent a tourniquet-use survey via e-mail, across Canada and the United States. Nineteen percent of the recipients completed and returned the surveys. Eleven (3.4%) rarely or never use a tourniquet and 8 (2.5%) use an Esmarch bandage tourniquet at the ankle. Most use pneumatic ankle cuffs (92% use, 27% use exclusively); many also use thigh cuffs (69%) and some also use calf cuffs (15%). Most thigh-cuff users (62%) experience problems with cuff fit sometimes or often. All but 3 respondents exsanguinate the limb before tourniquet inflation. Specific devices used for exsanguination varied among surgeons. Most commonly used tourniquet pressures range from </=200 to 350 mm Hg at the ankle and </=200 to >/=351 mm Hg for the thigh (64% use pressures between 301 and 350 mm Hg). Only 7% of respondents consider limb occlusion pressure when selecting tourniquet cuff pressure. Based on published studies of limb occlusion pressures, these ranges suggest that some of the more common pressure settings may be higher than necessary for many patients. Vascular disease or previous bypass (91%) and deep vein thrombosis (83%) were the most commonly listed contraindications to tourniquet use. Approximately 10% of respondents have either experienced or learned of skin and nerve injuries secondary to lower extremity tourniquet use at any level. The varied responses show a lack of overall consensus on tourniquet pressure settings. Guidelines for optimizing cuff pressure and technique should be established to minimize the risk of complications.

Downloading plantar foot pressures in the diabetic patient

Pressure downloading (offloading) is the most important component in the prevention and treatment of diabetic foot ulcers because peripheral neuropathy is a major contributing factor to more than 90% of all diabetic foot ulcers. Downloading techniques range from the simplest insole, through many types of orthotics and footwear modifications including the ankle-foot orthosis and total contact casting, to surgical procedures. A philosophical difference exists between surgical and nonsurgical approaches, with the patient subjected to the bias of the practitioner. This article explores uniting both surgical and nonsurgical pressure downloading techniques, using a modified Carville Classification System to help the practitioner determine the appropriate method(s) of downloading. By adding a Category 4 to include diabetic persons with foot ulcers or acute Charcot events, a seamless system is obtained to categorize and treat all people with diabetes with pressure downloading recommendations.

Orthosorb: a case of foreign-body reaction

The authors present a previously unreported foreign-body reaction to poly-p-dioxanone pin fixation of a distal first metatarsal head osteotomy. The reaction was diagnosed by fine-needle aspiration under fluoroscopic guidance and computed tomography scan. The patient responded to conservative therapy and time, but, still has residual pain 11 months after the surgery.

A calcaneal fracture from a fall or a fall from a calcaneal fracture?

A case of a calcaneal avulsion fracture from a relatively minor traumatic incident is presented. The mechanism of calcaneal avulsion fractures is discussed. Special attention is given to the possibility of a pathologic fracture. The literature is reviewed and treatment is discussed.