SEARCH

SEARCH BY CITATION

Keywords:

  • diabetes;
  • foot amputation;
  • below-knee amputation;
  • function;
  • limb salvage

Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Diabetic limb salvage
  5. Discussion
  6. Conclusion
  7. Conflict of interest
  8. References

The role of amputation in limb salvage is often poorly defined because the surgeon and the patient often attempt to save all limbs at all costs. The difficulty lies in selecting limb salvage versus early amputation. For the sedentary patient, a poorly functional salvaged limb can provide him/her with a higher quality of life than he/she would have with an amputation. For the active patient, early major amputation may offer the best functional outcome. Our experience with diabetic limb salvage over the last 20 years was retrospectively reviewed and compared with the existing literature in an attempt to better understand the role of amputation versus limb salvage in patients with diabetes. In the process, surgical techniques that we believe optimize foot and leg amputations were reviewed. Utilizing a team approach, limb salvage can yield a 64% ambulation rate and an 80% 2-year survival rate. Below-knee amputation led to a similar ambulatory rate, but the 2-year survival in these patients was 52%. With more severe rear-foot ulcers and osteomyelitis, the ambulatory rate declined with each co-morbity. However, those whose foot was saved had a higher chance of walking than those who underwent amputation. Function and quality of life are the outcomes of interest and may be maximized through either limb salvage or amputation. Our job as physicians is to match the correct solution to the patients' lifestyle and their medical, physical and psychological conditions so they can achieve their desired level of activity as quickly as possible. Level of evidence: IV. Copyright © 2012 John Wiley & Sons, Ltd.


Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Diabetic limb salvage
  5. Discussion
  6. Conclusion
  7. Conflict of interest
  8. References

The outcomes of younger patients who undergo amputation for trauma, cancer or birth defects cannot be compared with the outcomes of diabetic patients and their associated co-morbidities such as cardiac disease, peripheral vascular disease and/or renal failure. These two groups often have different expectations with the younger and more active patients wanting to resume life normally including full participation in all types of sports, hunting, fishing, climbing and others. Whereas some patients with diabetes share the same aspirations, most wish to be able to walk and resume the relatively sedentary life that they enjoyed prior to developing limb-threatening wounds. The diabetic patient's goal is to maintain independence at all costs and not be wheelchair dependent [1]. The older and less ambitious patients typically prefer to be able to carry out their acts of daily living without the inconvenience of donning a prosthetic.

Norvell assessed 87 nontraumatic amputees experiencing a first major unilateral amputation and found that only 37% equalled or exceeded pre-amputation mobility, whereas 57% were satisfied with their resultant mobility even if decreased [2]. Patients were less likely to achieve preoperative mobility if they were older than 65, an alcoholic and/or suffering from hypertension or depression [2]. Mobility is severely limited in those patients who are unable to use their prosthesis. Taylor found that amputees were ten times less likely to use their prosthesis if they were nonambulatory preoperatively, three time less likely if homebound, 2.7 times less likely if older than 60 and twice less likely if suffering from coronary artery disease [3].

The challenge is to accurately council patients regarding their likely functional outcome with limb salvage versus amputation. Maximizing the patients' quality of life ultimately lies in accurate patient selection and optimal surgical planning and technique.

Diabetic limb salvage

  1. Top of page
  2. Summary
  3. Introduction
  4. Diabetic limb salvage
  5. Discussion
  6. Conclusion
  7. Conflict of interest
  8. References

Our experience over the last 20 years in diabetic limb salvage was retrospectively reviewed and compared with the existing literature in an attempt to better understand the role of amputation versus limb salvage in diabetic patients. In the process, surgical techniques that we believe optimize foot and leg amputations were reviewed.

To help ensure success, both amputation and limb salvage start with the same approach:

  1. Ensure good blood flow;
  2. control infection;
  3. aim for a good biomechanical result
  4. create a stable soft tissue envelope.

Blood supply is critical to salvaging a limb. Physical exam continues to be a fast, available and inexpensive method for evaluating arterial inflow. Temperature, hair quality, dependent rubor, Doppler pulses, ankle and toe pressures, and ankle brachial indices all provide information regarding the arterial flow to an extremity and help determine which patients would benefit from an arteriogram. Tissue oxygen levels are time consuming, imprecise and have been shown to unreliably predict amputation level [4]. Laser Doppler is an excellent tool to measure blood flow in the microcirculation. Yamada showed that a skin perfusion pressure above 40 mmHg, as measured by laser Doppler, is associated with a healing rate of 69%, whereas a skin perfusion pressure above 50 mmHg is associated with a 100% healing rate [5].

With endovascular and bypass techniques available to restore blood flow, it is important to determine which technique is most appropriate in a given patient. Neville et al. have shown a twofold advantage to healing wounds when bypass surgery is utilized as compared with endovascular techniques [6]. An understanding of the angiosomes of the foot and ankle as well as the arterial–arterial connections between the main arteries of the foot is critical when planning revascularization of the foot as well as surgical incisions of the foot [7]. The salvage rate was 50% higher when the revascularized vessel was directly rather than indirectly supplying the angiosome that contained the wound [8].

Debridement is critical to prepare a wound for closure. When carried out with a knife, the surgeon should make thin tangential slices until viable tissue is reached. When one reaches tissue that is only red, yellow and white, then one has likely gotten rid of the diseased, infected or necrotic tissue. Postdebridement culture is a useful tool to assess the adequacy of the debridement and to guide antibiotic therapy. The reconstruction should be carried out at a later stage when the infection is under control [9]. In addition, if the leg has been revascularized by either bypass or angioplasty, it takes time for the affected tissue to feel the full effect of the new blood flow. We generally wait 4–10 days after bypass and 10–30 days after angioplasty before reconstruction.

When salvaging a limb, one has to create a foot that will hold up over time. An adequate protective soft tissue envelope must be created while existing and potential biomechanical abnormalities are corrected. The surgeon should avoid creating or leaving abnormal shapes. Equinovarus deformity and its complications can be minimized by rebalancing tendons and performing tendo-Achilles lengthening when indicated. Preservation of all viable tissue during debridement will often leave the foot with enough viable soft tissue for primary closure.

Before performing a transmetatarsal amputation (TMA), the surgeon must ensure adequate perfusion of the plantar and dorsal tissue and preserve the connection between the dorsalis pedis and lateral plantar arteries when necessary. When performing a TMA, it is important to recreate a parabola by making the second metatarsal osteotomy the most distal [10]. Patients who undergo a TMA will ultimately develop an equinovarus deformity because of the loss of toe extensors that formerly contributed to ankle extension and eversion. Barry showed that tendo-Achilles lengthening led to a 91% healing rate in diabetic patients with a TMA who suffered recurrent plantar ulceration [11].

When performing a Lisfranc amputation, it is important to preserve the proximal portion of the second metatarsal and tenodese the tibialis anterior tendon to the cuboid if possible. For both the Lisfranc and Chopart amputations, we also recommend using the durable and plantar skin to creatively cover the anterior aspect of the amputation. Resecting 1–2 cm of the distal Achilles tendon to avoid equinovarus deformity is necessary unless one uses a calcaneal tibial pin to fuse the ankle in neutral.

A Syme amputation can be a very useful amputation. Pinzur reported a series of 97 patients who underwent a Syme amputation. He found that 88% of patients with an ankle brachial index of above 0.5, a TcO2 20–30 mmHg and a serum albumin level above 2.5 g/dL went on to heal and were ambulating at 2 years post-operatively [12]. Frykberg reported their results in 26 high-risk patients who underwent a Syme amputation and found a 50% healing rate and a 46% ambulation rate [13].

When performing a below-knee amputation (BKA), it is important to understand that the sural arteries are often spared from peripheral vascular disease, allowing the use of a posterior myocutaneous flap (gastrocnemius and soleus muscles) to close the BKA. We make a tibial osteotomy 12–18 cm distal to the tibial tubercle and a fibular osteotomy 1 cm proximal to the tibial osteotomy. The anterior distal edge of the remaining tibia is bevelled, and three holes are drilled into the remaining cortex to tenodese the distal Achilles tendon to the tibia. Finally, the posterior myocutaneous flap is closed to create a well funnel-shaped stump. Despite our experience that the aforementioned technique creates the most functional BKA stump, a 2004 systematic review performed by the Cochrane Database concluded that the choice of amputation technique has no effect on the outcome and appeared to be a matter of surgeon preference [14].

In 1949, Jonas Ertl described the technique of creating a distal tibiofibular bone bridge that now bears his name [15] In theory, the Ertl technique should create an amputation stump that tolerates more axial loading and decreases discomfort as a result of increased distal tibiofibular stability as compared with traditional BKAs. Pinzur reviewed his series of 20 amputees who underwent distal tibiofibular bone bridging and did not find any difference in their outcome when compared with a matched cohort who did not have distal tibiofibular bone bridging [16].

Life expectancy decreases as each subsequent segment of the leg is amputated: toe < foot < lower leg < knee < thigh [17]. At Georgetown, we compared our survival and ambulation rate of foot amputees with below-knee amputees in 937 consecutive patients from 1999 to 2000. There were 88 foot amputations (TMA, Lisfranc and Chopart) of whom 80% were still alive at 2 years with 64% ambulating. There were 25 BKAs with 52% alive and 64% of those ambulating at 2 years. The higher mortality rate among the BKAs is probably explained by a selection bias against further limb salvage because of more advanced disease [18].

In looking at calcanectomies performed in elderly patients at our institution, we found that the ambulatory rate decreased with the severity of the co-morbidities. However, the ambulatory rate in the calcanectomy patients regardless of accompanying co-morbidities was higher than those patients who went on to have a BKA.

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Diabetic limb salvage
  5. Discussion
  6. Conclusion
  7. Conflict of interest
  8. References

Our data suggest that limb length is directly related to life expectancy. However, if the salvaged limb does not meet the expectations of the patient, an amputation should be considered. If one proceeds to a leg amputation, there is always a risk that the patient will not wear a prosthesis, and their function and quality of life will further decline. However, in the appropriately selected patient, function and quality of life may be better with a leg amputation than a salvaged limb.

The lack of reliable predictive data means that the physician must rely on his or her experience when counselling patients. A frank discussion with the patient as to what his or her expectations is critical in determining which option is most likely to achieve the best outcome. Both limb salvage and amputation should be discussed in every case. The more co-morbidities a patient has, the less likely they are to ambulate with prosthesis [3]. In these ill patients, limb salvage often offers a better outcome than amputation.

Determining the correct solution requires answering the following questions: Can the patient survive the multiple surgeries required for limb salvage? Can the patient afford time off work for limb salvage? Will the patient's insurance cover the cost of limb salvage? What will the patient have to cover in terms of out-of-pocket expenses? Will the salvaged leg be biomechanically sound so that it will not breakdown over time?

If the leg can be salvaged, one must be creative to meet the patient's expectations using what his or her medical condition and the remaining foot will allow. Creating a biomechanically sound foot that will hold up over time is critical. This may require partial amputation or calcanectomy, microsurgery, tendon rebalancing and other procedures. If the salvaged limb cannot meet the patient's realistic expectations, the patient and the physician must consider a BKA. It is important to have a prosthetist involved with this decision as well as a peer who has had to face similar choices.

Conclusion

  1. Top of page
  2. Summary
  3. Introduction
  4. Diabetic limb salvage
  5. Discussion
  6. Conclusion
  7. Conflict of interest
  8. References

The most functional leg for a given patient might be achievable via limb salvage or amputation. Our task as physicians is to determine the best solution for each patient such that they have the highest likelihood of achieving their desired level of activity as quickly as possible.

References

  1. Top of page
  2. Summary
  3. Introduction
  4. Diabetic limb salvage
  5. Discussion
  6. Conclusion
  7. Conflict of interest
  8. References
  • 1
    Buzato MA, Tribulatto EC, et al. Major amputations of the lower leg: the patients two years later. Acta Chir Belg 2002; 102(4): 248252.
  • 2
    Norvell DC, Turner AP, et al. Defining successful mobility after lower extremity amputation for complications of peripheral vascular disease and diabetes. J Vasc Surg, April 2011, Epub; 54(2): 412419.
  • 3
    Taylor SM, Kalbaugh CA, et al. Preoperative clinical factors predict postoperative functional outcomes after major lower limb amputation: an analysis of 553 consecutive patients. J Vasc Surg 2005; 42(2): 227235.
  • 4
    Faglia EG, Clerici G, et al. Predictive values of transcutaneous oxygen tension for above-the-ankle amputation in diabetic patients with critical limb ischemia. European J Vasc Endovascular Surg 2007; 33(6): 731736.
  • 5
    Yamada T, Ohta T, et al. Clinical reliability and utility of skin perfusion pressure measurement in ischemic limbs—comparison with other noninvasive diagnostic methods. J Vasc Surg 2008; 47(2): 318323.
  • 6
    Neville R. Wound healing in open vs. endovascular bypass. Presented at SVS: Boston, MA, 2010.
  • 7
    Attinger CE, Evans KK, Bulan E, Blume P, Cooper P. Angiosomes of the foot and ankle and clinical implications for limb salvage: reconstruction, incisions, and revascularization. Plast Reconstr Surg 2006; 117(7 Suppl): 261S293S.
  • 8
    Neville RF, Attinger CE, Bulan EJ, Ducic I, Thomassen M, Sidawy AN. Revascularization of a specific angiosome for limb salvage: does the target artery matter? Ann Vasc Surg 2009; 23(3): 36773.
  • 9
    Fisher DF, Clagett GP. One-stage versus two-stage amputation for wet gangrene of the lower extremity: a randomized study. J Vasc Surg 1988; 8(4): 428433.
  • 10
    Hamilton GA, Ford LA. Salvage of the neuropathic foot by using bone resection and tendon balancing: a retrospective review of 10 patients. J Foot Ankle 2005; 44(1): 3743.
  • 11
    Barry DC, Sabacinski KA. Tendo Achillis procedures for chronic ulcerations in diabetic patients with transmetatarsal amputations. JAMPA 1993; 83(2): 96100.
  • 12
    Pinzur MS, Stuck RM. Syme ankle disarticulation in patients with diabetes. J Bone Joint Surg Am 2003; 85-A(9): 16671672.
  • 13
    Frykberg RG, Abraham S, et al. Syme amputation for limb salvage: early experience with 26 cases. J Foot Ankle Surg 2007; 46(2): 93100.
  • 14
    Tisi PV, Callam MJ. Type of incision for below knee amputation. Cochrane Database Syst Rev. 2004; (1): CD003749. Review.
  • 15
    Ertl J. Uber amputationsstumpfe. Chirurg 1949; (20): 218224.
  • 16
    Pinzur MS, Beck J, et al. Distal tibiofibular bone-bridging in transtibial amputation. J Bone Joint Surg Am 2008; 90(12): 26822687.
  • 17
    Mayfield JA, Reiber GE, Maynard C, Czerniecki JM, Caps MT, Sangeorzan BJJ. Survival following lower-limb amputation in a veteran population. Rehabil Res Dev. 2001; 38(3): 3415.
  • 18
    Evans KK, Attinger CE, Al-Attar A, et al. The importance of limb preservation in the diabetic population. J Diabetes Complications 2011; 25(4): 22731.