A Retrospective Quality Improvement Study Comparing Use Versus Nonuse of a Padded Heel Dressing to Offload Heel Ulcers of Different Etiologies

Offloading heel ulcers is a challenging task because strategies deemed to be most optimal from a medical perspective may be unacceptable to patients. Observed adverse dressing events and problems with offloading devices led to a pilot study and subsequent change in practice at the authors’ Foot and Leg Ulcer Clinic. Starting in 2004, patients requiring offloading received a nonremovable padded heel dressing (PHD) that was changed twice a week by the visiting nurse. A retrospective quality improvement review was conducted to compare outcomes, nursing visits, and nursing visit costs for 40 consecutive patients with heel ulcers treated at this clinic with a nonremovable PHD (n = 20) or without a PHD (n = 20) between January 20, 2001 and December 31, 2006. Patient demographic data, relevant comorbidities, wound depth, weeks of care, adverse events, and treatment-related narrative comments were abstracted from patient records. Relevant comorbidities were similar in both groups. The PHD group was younger (average age of 74.6 [range 35–91] years) compared to PHD nonuse group (average age 79.5 [range 25–95] years; P <0.04). The PHD group required fewer total weeks of care compared to the nonuse group  (368 versus 527 weeks, respectively; P <0.001), and average duration of clinic treatment in the PHD group was 18.40 (range 5–51) weeks versus 40.54 (range 6–88) weeks in the nonuse group. The PHD group had fewer total nursing visits (736 versus 1,581, P <0.001); the average number of nursing visits for the PHD was 36.80 (range 10–102) compared to 121.61 (range 18–264) for the nonuse group. Nursing visit costs were lower for PHD users ($114,080 versus $245,055, P <0.001), and the cost-efficiency ratio was less than one third (1:3.3) of PHD nonuse for the average heel ulcer. All 20 patients in the PHD use group had wound closure compared with the PHD nonuse group, in which 13 out of 20 wounds closed, 3 amputations were performed, and 4 patients were lost to review (P <0.000). No adverse events were reported in the records of the PHD use group; the PHD nonuse group reported periwound maceration, skin stripping, pressure injury, and sensitivity. Patient and nurse feedback identified pain relief, improved mobility, easy technique, low cost, and reduced workload as benefits of PHD. The results of this quality improvement review warrant a prospective clinical study to examine the efficacy, effectiveness, and cost-effectiveness of PHD for the care of patients with heel ulcers.  

Heel ulcers are a life-altering condition associated with a substantial risk for delayed healing, infection, amputation, or death.¹ The quality-of-life impact is noteworthy; patients with diabetes who have experienced foot ulcers have a better quality of life with healed than with open ulcers and a lower quality of life if amputation was required.^2-4 Among pressure ulcers, the heel is the second most common anatomical ulcer site after the sacral area.⁵ The incidence of heel ulcers has been reported to be between 19% and 32% in patients with and without diabetes in acute and residential care facilities, respectively.¹ Improving ulcer healing, reducing amputations, and preventing ulcer reoccurrence requires knowledge of the etiology of heel ulcers and critical evaluation of efficacy of interventions.

Anatomy of the heel. Plantar soft tissue, a specialized, pressure-absorbing, closed-cell structure of fibrous septae-containing adipocytes, serves to protect the structures of the foot.⁶ Just below the dermis, this tissue is organized into microchambers; deeper in the foot, over bone or tendon, plantar soft tissue is organized into macrochambers. The plantar soft tissue covering the calcaneus is commonly known as the heel pad. The soft tissue layer covering the calcaneus, lateral foot, metatarsal heads, distal phalanges, and distal hallux is thicker than over the medial foot, proximal hallux, and proximal and intermediate phalanges (see Figure 1). When a person is standing, pressure is unevenly distributed over the plantar surface, with the highest pressure over the heel; the first, second, and third metatarsal heads; and the hallux.

The principal arteries supplying the heel are the posterior tibial and peroneal arteries.⁷ The subdermal plexus and periosteal plexus are well vascularized, with vessels within the fibrous septae that travel between the 2 arteries. The panniculus canosus muscle, located in the subcutaneous tissue, is sensitive to damage from pressure, mechanical trauma, and shear. These forces also may injure blood vessels and other tissues of the foot. A unique feature of plantar adipose tissue is that it is not replaced after injury or loss, and maintenance of the resilient, shock-absorbing heel tissue depends on pressure absorption, adequate arterial supply, and prevention of injury.

Risk factors for heel ulcers. Reviews of the literature^1,5 list the causes of heel ulcers as callus, trauma, diabetes, foot deformities, neuropathy, peripheral arterial disease, reduced joint mobility, and limb immobility. Hsu et al⁸ studied a convenience sample of 33 volunteers with no heel problems to determine the effect of age on the mechanical properties of the heel pad. Two groups, divided by age into young (18–36 years) and elderly (62–78 years), were provided ultrasound examination of the heel pad during sequential loading and unloading using increments of 0.5 kg to a maximum of 3 kg to produce a load-displacement curve. Heel pads were found to be significantly thicker, more compressible, and less elastic in the elderly (all P <0.001). The combination of these findings, along with the increased fragmentation of elastic fibers and collagen reduction occurring with age, may help explain the reduced pressure absorbency of the heel pad and higher risk of tissue injury in older individuals. 

Multiple factors may be linked to diabetic foot ulcer development. Reiber et al⁹ used the Rothman model of causation, a blinded multidisciplinary group of foot specialists, and a modified Delphi process to identify causal pathways for 92 persons with diabetes and diabetic foot ulcers from Manchester, United Kingdom and 56 from Seattle, WA. The process identified a critical triad of neuropathy, minor foot trauma, and foot deformity in the causal pathway of 63% of patients. Edema and ischemia were present in more than one third of cases. Single causes were callus formation (30%), trauma (6%), and edema (1%).

Descriptive studies^10-12 focusing on preventing heel ulcers or characterizing patients with heel ulcers, conducted in inpatient and community settings, indicate risk assessment tools, such as the Braden Scale for Predicting Pressure Sore Risk, appear to be relatively insensitive to risks associated with heel ulcer development, at times placing patients with ulcers in the mild or not-at-risk categories.

Pressure Offloading in Heel Ulcer Management

A Cochrane review found nonremovable, pressure-relieving casts are more effective in healing foot ulcers in persons with diabetes mellitus than removable casts or dressings alone.¹³ A systematic review and meta-analysis¹⁴ of the clinical effectiveness of different offloading devices found any type of nonremovable offloading device to be more effective than removable devices in the treatment of diabetic foot ulcers, likely because patient adherence is facilitated. At this time, pressure offloading with a total contact cast (TCC) or instant total contact cast (iTCC) is considered the optimal method of pressure management in patients with foot ulcers; both options are considered equally effective.^15,16 Although TCC and iTCC are effective for offloading, these devices may be associated with clinical disadvantages, including joint stiffness, muscle atrophy, and the risk of new ulceration; elderly, frail, or immobile patients may not tolerate TCC.^17-19 An additional concern is the need to transition offloading effectively to maintenance footwear (both shoes and slippers) to prevent recurrence.¹⁷ However, in terms of heel ulcer prevention, a systematic review²⁰ of pressure redistribution strategies and heel protection devices found insufficient evidence to select any particular device over a foam pillow.

A prospective pilot study²¹ compared a “football” dressing (consisting of a topical silver primary wound dressing, cast padding, and a self-adhesive wrap) with TCC or iTCC in 15 patients with chronic neuropathic ulcers that had a mean duration of 6 weeks. All 15 patients healed in 3.80 ± 2.60 weeks (range 1–10 weeks), but pressure relief over the metatarsal heads was 30% less with the football dressing than with TCC or iTCC. The incidence of infection was similar in both groups, and no dressing-related injuries were reported. A retrospective, multicenter analysis²² of the football dressing confirmed these findings and concluded the wound outcomes, coupled with ease of application and low cost, made the football dressing a useful choice in managing foot ulcers. 

Dressing-related and offloading device-related injury. In the authors’ clinic, dressings and offloading devices have been linked with adverse events contributing to patient injury. Dressing-related injuries observed included periwound maceration, skin stripping, and pressure injury (see Figure 2).

Offloading devices may contribute to pressure ulcer development, foot-drop, or lower limb rotation; thorough patient assessment is essential before selecting a device to reduce these risks. It is critical to consider the impact of the loss of protective sensation, peripheral arterial disease, infection, and exudate management.¹⁷ It is also important to examine patients while they are using the device and to assess comfort and any impact on their ability to reposition, stand, or walk.

Adverse events and patient intolerance may be associated with interventions such as the use of pillows to “float” the heel, heel protectors, and nonremovable or removable pressure-relief devices. Although clinical guidelines recommend the use of pillows to float the heel, it is essential to ensure adequate calf support to prevent Achilles pressure ulcers.²³ Incorrect placement or displacement because of patient movement may result in Achilles tendon pressure ulcer development, especially in the presence of peripheral arterial disease. Removable devices, such as the Aircast^® (Aircast Inc, Vista, CA) or ankle foot orthoses, have been noted in the authors’ clinic to cause pressure injury, trauma to the unaffected limb, and patient complaints of back or hip pain. Figure 3 illustrates pressure injuries associated with offloading interventions.

Evolution of the Padded Heel Dressing

The padded heel dressing (PHD) was conceived at the Foot and Leg Ulcer Clinic in Victoria, British Columbia (BC), when one of the authors, a clinical wound specialist, wrapped a heel ulcer in a patient with advanced peripheral arterial disease with cast padding in an attempt to relieve his intractable pain. The patient experienced immediate pain relief and was able to ambulate wearing running shoes with laces adjusted for the dressing size. Previously, he had been unable to tolerate use of an Aircast because of back and hip pain experienced with the device. Protected by the PHD, the ulcer healed in 2 months.

Pressure mapping. The clinic team then performed a pressure mapping study in 5 healthy adult volunteers (2 men, 3 women) to determine if the PHD affected heel pressure. The volunteer sat on a plinth at 45˚ with the foot straight in a natural comfortable extension. A CONFORMat^® (Tekscan, Boston, MA) was placed under the heel. Measurements were performed for a bare heel as a baseline and for 1-roll and 2-roll padding with 4-inch Zimmer Orthopedic Cast Padding (Zimmer Orthopedic Surgical Products, Dover, OH) to determine appropriate dressing recommendations. Compared with the baseline pressure for a bare heel, average pressure reductions were 23% with 1 roll of padding and 39% with  2 rolls of padding (see Figure 4). This pressure-mapping result indicates the PHD may reduce heel pressure.

Pilot project. To address existing issues with standard dressings (including adverse events), facilitate offloading for heel ulcers, and potentially provide PHD pain relief, the clinic team decided to conduct a pilot study of the PHD among primary care nurses treating patients in both community and residential care settings. The team trained the nurses on dressing application procedure (see Table 1) and evaluated outcomes after the first 10 cases. Nurses reported the PHD was easy to apply, stayed intact between twice-weekly dressing changes, improved exudate control, facilitated wound healing, resolved the problem of periwound skin stripping, required fewer dressing changes, and reduced confusion about dressing selection. With a cost of between $6 and $8 CAN, the PHD was less expensive than previously used heel dressing of various types (eg, hydrocolloid, foam, alginate) with or without a topical antimicrobial product that ranged from $12.50 to $25.00 per change except for adhesive bandages, gauze, and gauze wrap, which cost $0.50 to $5.00. Patients using the PHD could wear loose clothing and resume social activities. Ambulatory patients could use footwear modified by an occupational therapist or pedorthist to ambulate at their previous level; nonambulatory patients could reposition themselves independently; and immobile patients were easier for staff to reposition. Community and residential management reported reductions in nursing time, number of dressing changes, and dressing product inventory.

Based on the results of the community and residential pilot of the PHD, in 2004 the Foot and Leg Ulcer Clinic decided to recommend the PHD for heel ulcers, and in 2007 a quality improvement review was approved.

Quality Improvement Review

The quality improvement review analyzed data from a retrospective chart review to answer the following questions:

1. Did patient characteristics (age, peripheral arterial disease, diabetes, and neuropathy) differ between the PHD use and nonuse groups?
2. Did ulcer outcomes (closure, amputation, and lost to review), weeks of care, number of nursing visits, nursing costs, and cost-efficiency ratio (CER) differ between the PHD use and nonuse groups?
3. What were the average weeks of care, nursing costs, and CER for the PHD use and nonuse groups by depth of tissue involved (superficial skin and muscle, heel pad or tendon, and bone)?
4. What was the feedback from primary care nurses and management about adverse events, utility, cost, and satisfaction for the PHD use and nonuse groups?
5. What feedback did patients in the PHD use and nonuse groups provide about dressings and offloading devices, dressing experience, pain relief, comfort, physical activity, social interaction, and quality of life?

Standard care at the Foot and Leg Ulcer Clinic. The standard care at the clinic for lower extremity ulcers involves a comprehensive multidisciplinary admission assessment, including comorbidity assessment, lower limb vascular assessment, neuropathy screening, infection screening, ulcer assessment and wound management, pressure offloading, gait analysis, and footwear assessment. Additional investigations, treatments, and referrals are performed as required to manage identified problems.

After comprehensive assessment, investigation, and setting care priorities at the clinic, patients return with their care plans (including information about patient risks) to their primary care providers for management. Primary care providers consult with the clinic as required, and the clinic team reviews each patient monthly or more frequently, if necessary.

All primary care providers using the PHD were provided with an illustrated procedure used in the clinic (see Table 1) and access to application training. Primary care nurses continued using the PHD for 2 weeks after ulcer healing to allow the pedorthist adequate time to arrange for appropriate footwear to reduce the risk of ulcer recurrence. The only difference in wound management was the use or nonuse of the PHD for wound management and offloading the heel ulcer.

Patient population. Patient data analyzed for the quality improvement review were collected from regional health authority records on patients with heel ulcers who had been treated at the Foot and Leg Ulcer Clinic between January 20, 2001 and December 31, 2006. Patient records were hand-searched to identify the study population, which comprised a convenience sample of 20 consecutive patients with a heel ulcer who had been treated with the PHD throughout their treatment and 20 consecutive patients with a heel ulcer who had been treated with an alternative dressing. Patients with heel ulcers that were referred for amputation after the clinic admission assessment were excluded. 

Clinic patients routinely provide consent for treatment and have consented that clinical data may be used for clinical, education, or research purposes. In addition, patients were consulted and agreed to treatment throughout their care process. As a result, the Research Ethics Committee in Victoria, British Columbia, decided ethical approval was not required for performing the PHD quality improvement review.

Data abstraction and analysis. Members of the clinic team extracted the following data from patient records: patient age; presence of peripheral arterial disease, diabetes, or neuropathy; deepest tissue involved in the heel ulcer (superficial skin and muscle, heel pad or tendon, or bone); wound outcomes (closed, amputation, or lost to review); weeks of care; number of nursing visits; and adverse events. 

Documented information about the patient’s mobility status, pain, and dressing experience was extracted for the purposes of the review. Consultation with primary care nurses and residential care management contributed feedback about their perception of the role of the dressings in patient care, social functioning, and operational considerations such as cost, inventory management, and elimination of dressing selection confusion. Feedback from patients and primary care nurses was discussed by the 2 wound specialist clinic nurses and noted, but not tabulated, in a log book to inform beneficial clinical changes (eg, the illustrated PHD application procedure) and guide development of a heel ulcer management plan.

The clinic nurses entered the data into Microsoft Excel spreadsheets. The Department of Mathematics and Statistics at the University of Victoria provided assistance in performing the statistical analysis of comparisons for the total PHD use and nonuse groups of wound outcomes (one-way ANOVA) and comorbid conditions and age (Pearson chi square). The clinical wound specialist calculated the CER, which quantifies the differences in cost between alternatives, for the PHD use group compared with the PHD nonuse group by dividing the higher by the lower cost. Patient data for average weeks of care and average nursing visit costs also were analyzed by depth of tissue involved and the CER calculated for these averages by the clinical wound specialist.

Patient demographics. A significant difference (P <0.04) was found between the groups for age; the PHD nonuse group was older (average age 79.5 [range 25–95 years] versus 74.6 [range 35–91 years). No difference was found in the proportion of patients with comorbid diseases, peripheral arterial disease, diabetes, neuropathy, or ulcer depth classification (see Table 2).

Wound outcomes. Overall wound outcomes differed significantly (P <0.000) between the groups; 20 out of 20 (100%) heel ulcers closed in the PHD use group, compared with 13 out of 20 for the PHD nonuse group. Total weeks of care was significantly shorter for the PHD use than the nonuse group (368 versus 527 weeks, respectively; P <0.001). The PHD nonuse group had 3 amputations and 4 patients lost to review; all resided in nonaffiliated care agencies where data for duration of care, number of nursing visits, and nursing visit costs were not accessible. To compensate for missing data, the averages and range data for known heel ulcer patients were used to compare duration of care, number of nursing visits, nursing visit costs, and CER. 

The number of nursing visits, a measure of the number of weeks for ulcer closure plus 2 weeks, was significantly greater in the PHD nonuse than in the use group (1,581 versus 736, respectively; P <0.001). The cost of nursing visits, based on an administrative cost for a community or clinic visit of $155 CAN, was significantly greater for the PHD nonuse (n = 13) than the PHD use (n = 20) group ($245,055 versus $114,080, respectively; P <0.001). A CER of 1:3.3 for the average heel ulcer indicates the cost of nursing visits for the PHD nonuse was more than 3 times higher than the PHD use group.

Depth of tissue involvement. To gain insight into the influence of the depth of tissue involvement on the number of nursing visits, nursing visit costs, and CER, per-patient averages were calculated for both groups for each depth of tissue involved (see Table 3). On admission, the number of heel ulcers by depth was equal for use and nonuse groups: 10 superficial, 6 heel pad and 4 bone. Data were not available for the PHD nonuse group due to amputations and lost patients, leaving 7 (out of 10) superficial, 4 (out of 6) heel pad, and 2 (out of 4) bone tissue depth ulcers. PHD group average weeks of care were 15, 12, and 39 compared to the PHD nonuse average weeks of care of 32, 37, and 83 for superficial, heel pad, and bone, respectively

The average number of nursing visits and nursing visit costs were lower in the PHD use group than in the PHD nonuse group for ulcers of all tissue depths. Average nursing costs for the PHD group included $4,588 (superficial), $4,288 (heel pad), and $12,168 (bone) compared to costs in the PHD nonuse group of $14,946 (superficial), $19,898 (heel pad), and $38,595 (bone). The CER demonstrates that compared to the PHD use group, the nursing visit costs for the PHD nonuse group were 3.3 times greater for superficial ulcers, 2.31 times greater for ulcers reaching the heel pad or tendon, and 3.17 times greater for ulcers reaching bone (see Table 3).

Adverse events. No adverse events were reported in the PHD use group, whereas periwound maceration, skin stripping, pressure injury, inadequate exudate management, premature detachment, contact dermatitis, and pressure injury associated with an ankle foot orthosis (possibly related to improper fit or application) were reported in the PHD nonuse group.

Pain and patient experience. Patients in the PHD use group infrequently reported heel ulcer pain, resumed their previous level of physical activity, and participated in social activities. Previous dressings were associated with several patient concerns, such as inadequate exudate management, skin problems, and odor, but these concerns were not reported with the PHD. Both patients and care providers reported the PHD was less awkward, lighter, and easier to apply than heel offloading devices they had used previously.

Patients who declined or discontinued commercial heel offloading devices such as the Aircast because of price, inability to walk or imbalance, back or hip pain, and the weight of device were able to tolerate the PHD as an alternative.

Pressure offloading is a critical factor in achieving wound closure in heel ulcers. The superior effectiveness of the TCC and the iTCC over removable devices is supported by strong evidence.^15-17,24 Although these devices are recommended as first-line offloading options, clinical experience indicates they tend to be underused in practice because they can be both expensive and difficult for patients to manage: they are heavy, restrictive, and can cause balance problems.¹⁸ These physical disadvantages can be especially important to the population with heel ulcers, often elderly, who may have limited physical capacity for standing, walking, or repositioning. In addition, TCC is usually contraindicated in the presence of infection or ischemia and there is insufficient evidence for the management of heel ulcers, because TCC may transfer significant pressure to the posterior foot.^17,18

An online survey²⁵ of Australian podiatrists investigated the offloading strategies used for patients with diabetes-related plantar neuropathic ulcers; the survey respondents considered patient adherence, adverse effects, psychosocial factors, restrictions to patients’ daily life, and wound features when selecting an offloading option. Of the 36 (out of 41, 88%) who responded to the survey, the majority of participants (30, 83%) considered nonremovable casts or walkers to be the gold standard for offloading plantar ulcers based on the evidence. However, numerous barriers, especially patient-related issues, made nonremovable casts their last choice for offloading in clinical practice after felt padding and removable casts or walkers. Participants identified numerous patient barriers to use of nonremovable devices, including lack of acceptance of or inability to tolerate a nonremovable device, poor adherence to instructions, negative impact on patient lifestyle, issues with transportation or driving, and difficulties managing the device in the patient’s home environment. Wound-related barriers identified by respondents included a reduced ability to monitor and dress the wound. In addition, study participants believed highly exudative, deep, large, or infected wounds requiring frequent monitoring or care were unsuitable for nonremovable casts. Practitioner-related barriers to the use of nonremovable devices generally included the need for adequate staff resources, primarily in terms of time, expertise, and on-call emergency availability. Armstrong et al²⁶ discussed contraindications for TCC (soft tissue infection, osteomyelitis, or peripheral arterial disease) and cautioned use for heel ulcers due to excessive pressure on the hind foot.

The results of the survey²⁵ demonstrate identifying the most appropriate offloading strategy for an individual patient can be a complex process requiring consideration of multiple variables. Furthermore, the results highlight the need for broad-based research into factors affecting the success of offloading strategies, including patient experience, quality of life, and the effectiveness of alternative offloading approaches. Generating such information could help guide selection of an offloading strategy when the TCC and iTCC are either unsuitable or not accepted by the patient.

This retrospective quality improvement review found the PHD can overcome many patient-related barriers associated with use of other nonremovable offloading devices such as the TCC and iTCC. The ability of patients to maintain their previous physical activities with the PHD helps prevent deconditioning from mobility restrictions with other devices. Furthermore, because patients can wear running shoes with the PHD, balance is not affected as it can be with more cumbersome devices. The PHD is also fast and simple for clinicians to apply, and the clinician is able to monitor wound healing because the PHD is changed twice weekly.

The Foot and Leg Ulcer Clinic is a referral clinic that serves a specific patient population with complicated conditions. Patients may be referred to the clinic for nonresponse to therapy, debridement of necrosis, wound deterioration, amputation risk, clinical management problems, or other complications. As a result, the outcomes of this quality improvement review apply to dressing selection in this high-risk population. In addition, because a quality improvement review is a decision-making support tool, not a clinical trial, a prospective clinical trial is needed to evaluate the outcomes obtained in this review.

A quality improvement review demonstrated good clinical outcomes in terms of number of ulcers healed, number of nursing visits required, and decreased costs with the PHD. Based on the positive outcomes of this retrospective review, it would be beneficial to investigate the performance of the PHD as a dressing, a nonremovable offloading device, and a preventive strategy for the management of primary and the prevention of recurrent heel ulcers. 

This quality improvement review was independent of any corporate influence. The authors thank the clinic team and patients who consented to have their pictures and experiences accessible for education and research purposes. Thank you also to Karen Li of the British Columbia Ministry of Health, who performed the statistical analysis and consulted on interpretation of the data. Editorial support was provided by Joanna Gorski of Prescriptum Health Care Communications Inc.

Ms. N. Campbell was the Clinical Specialist (Wound Care), Ms. D. Campbell was a Clinical Leader, and Ms. Turner is presently an Acting Clinical Leader at the Foot and Leg Ulcer Clinic, Vancouver Island Health Authority, Vancouver, British Columbia, Canada. Please address correspondence to: Andrea C. Turner, 5631 West Saanich Road, Victoria, BC V9E 2G1, Canada; email: aturner@shaw.ca.