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Selection of level for lower limb amputation
Current Orthopaedics (1996) 10, 239 246 © 1996Pearson ProfessionalLtd
Amputation
Selection of level for lower limb amputation
G. A. Hunter
The limb should then be examined with particular reference to:
INTRODUCTION Lower limb amputations in the dysvascular patient or following lower limb trauma should be performed at the most distal site compatible with wound healing and with 'suitable prosthetic fitting and rehabilitation in mind'. The selection of level of amputation of the lower limb should be based on a thorough history and physical examination of the patient followed, where necessary, by appropriate radiographic and vascular studies (Fig. 1).
1. the amount of rest pain; 2. the skin temperature and appearance on elevation and dependency of the limb; 3. the level of palpable pulses; 4. the quality of venous return; 5. muscle tenderness, particularly in the calf (this usually indicates severe ischaemia); 6. the extent of ulceration, necrosis and infection of the limb; 7. associated neuromuscular and musculoskeletal problems, e.g. hemiplegia and arthritis; 8. onset of the disease, whether it is acute (embolism), or chronic (thrombosis) with better collateral circulation.
GENERAL ASSESSMENT
In dysvascular cases, the entire patient should be reviewed with particular emphasis on:
The patient and relatives will insist on amputation at the most distal level, preserving all length possible, feeling in this way that the patient will manage better after the operation. Although their wishes must be respected, this policy may lead to 'a hit-and-miss procedure', resulting in one or more painful revision procedures and unnecessary increased local and systemic morbidity. Preoperative vascular measurements
1. the general medical and mental health of the patient (cognitive skills activity level and possible prosthetic use); 2. the morbidity and mortality rates of the proposed procedure; 3. the nutritional status is considered adequate if the serum albumin level is at least 3.5 gmdL, and if there is a total lymphocyte count of more than 1500 cells/mm3; 4. the status of the contralateral limb (when present); 5. the social situation of the patient; 6. the natural history of the amputee with respect to the prognosis, eventual function and independence, quality of life and possible or probable use of a lower limb prosthesis. G. Hunter MB FRCS FRCS (C), ConsultantOrthopaedic Surgeon, SunnybrookHealth SciencesCentre (SCIL),2075 BayviewAvenue,North York, Ontario M4N 3M5, Canada. Address correspondence to: G. Hunter
Fig. 1 Gangreneof medialforefoot.What levelof amputation?
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Current Orthopaedics will depend on whether the arterial damage is above or below the knee; 2. the necessity for local or free flaps to cover bone in order to preserve length, although these flaps are usually covered by split skin grafts, which do not have normal sensation; 3. a knowledge of the long-term results of lower limb amputees with reference to comfort, prosthetic use, return to work and recreational activities. How many surgeons involved in trauma care regularly attend an amputee clinic to assess the results of their surgical treatment (Figs 3, 4 & 5)?
Fig. 2 TypeIII C fractureof the tibia requiringearlythroughknee disarticulation.
are more beneficial in predicting failure than in predicting success. There is considerable evidence to support the use of a Doppler ultrasonography cut-off range of 50 to 70 mmHg at the lower part of the thigh for deciding on whether or not to do a trans-tibial amputation. With this simple reference, many transfemoral amputations could be avoided, but there would be a few trans-tibial failures as a consequence. 1 The ankle-arm Doppler arterial pressure ratio of at least 0.45 (diabetics) and 0.35 (peripheral vascular disease) has been previously used as the gold standard, 2 but subsequent studies3 have indicated that this ratio is unreliable because of calcification of the lower limb arteries in diabetic patients. In this same study of trans-tibial amputations, transcutaneous oxygen pressures of at least 30 mmHg at the proposed site of amputation were a good indicator of successful healing, whereas that of 20 to 30 mmHg warrant more serious consideration. When the transcutaneous oxygen pressure is below 20 mmHg, this finding should contraindicate a trans-tibial amputation, and consultation with a vascular surgeon should be obtained in the hope that angioplasty or revascularization will be possible, thus permitting a more distal amputation. After trauma, there are many scoring systems available to predict salvage or amputation of the lower limb. There is little written about the selection of level of amputation in trauma, and even less about the eventual outcome and quality of life of the patient following early or delayed amputation, when compared with salvage of the lower limb, which may entail many costly procedures (bone grafts, free flaps or use of the Ilizarov technique).4 The author has previously published in this Journal a discussion of the absolute and relative indications for primary (0-7 days) amputation of the lower limb. 5 The selection of level of amputation must be influenced by such factors as: 1. local damage to skin, muscle, nerves, bone or joint with or without reparable damage to the major blood vessels of the lower limb (Fig. 2), and much
Severe lower extremity trauma usually occurs in young males and is often associated with lifethreatening injuries to the head, chest, spinal column and abdomen. The level of" amputation is usually determined by the injury itself; but there is little to be gained by 'conserving all length possible' if it is not combined with good surgical judgment as to the eventual functional outcome of the amputee with reference to a well healed stump, available prosthetic fitting and the level of function to be expected at work and at home. Early thorough wound debridement should be combined with delayed secondary closure and early post-operative prosthetic fitting and rehabilitation should be organized within a specialized unit.
AMPUTATION OF THE TOE(S) This procedure is commonly used after trauma (lawnmower, boat propeller and industrial accidents). Vascular supply is not usually a problem. Skin flaps should be generous to avoid tension. The wound should be left open initially and closed secondarily to reduce the incidence of infection. Skin grafts may be used on the dorsum of the foot, but skin grafts on the plantar aspect of the foot should be avoided if possible in this load-bearing surface. The toe(s) may be disarticulated at any of the joints, through the phalanges or removed along with the metatarsal heads where necessary to allow adequate skin healing. Subsequent fitting of modified footwear and a soft orthotic device, with or without a toe filler, should provide adequate function and enable the patient to return to work and full recreational activities. In dysvascular patients, Burgess 6 estimated that less than 5% of patients with gangrene of the toe(s) caused by athero-osclerosis will heal after simple toe removal alone. Hunter 7 reported the results of amputation of the toe(s) in 128 operations in dysvascular patients (diabetic and non-diabetic). Only 42 out of 128 (33%) healed at 3 months. The results suggested that diabetic patients with ischaemic feet (i.e. an absence of foot pulses) should not be treated any differently from non-diabetics when amputation is being considered. The results of removal of one or more toe(s) were enhanced if vascular reconstruction had
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Figs 3, 4 & 5 Poor surgicaljudgmentleadsto difficultieswithprostheticfitting.
Fig. 6 Auto-amputationof toe (s) maytake manymonths.
Fig. 7 Trans-metatarsalamputationafterlawnmowerinjuryto all toes.
been performed during the preceding month. Little8 reported that by 30 months from the time of toe amputation in vascular disease, 50% of the patients had lost the affected leg. By 42 months, almost threequarters had come to major amputation. Removal of the toe(s) is not therefore recommended in dysvascular patients, unless vascular surgery or angioplasty has been successful in improving the circulation to the foot prior to the amputation. There is a small but limited group of patients who should be allowed to undergo auto-amputation of their toe(s) in the presence of pure necrosis of the end of the toe(s) without significant infection. This process may take many months, and the patient should be warned of this prolonged convalescent period (Fig. 6).
of diabetic patients with gangrene or chronic osteomyelitis of the toes, provided vascular studies are satisfactory. In the largest reported series in the literature, Wheelock9 reported on healing in 213 out of 336 (63%) of transmetatarsal amputations in diabetic patients. Hunter 7 reported successful transmetatarsal amputation, i.e. wound healing at 3 months in 12 out of 26 (46%) procedures in dysvascular patients (diabetic and non-diabetic). Pinzur I° reported on 64 amputations performed at the middle level of the foot in 58 patients. Successful wound healing was reported in 81% of this group of patients. If the amputation was performed at the tarsometatarsal level, it was combined with percutaneous lengthening of the tendo Achilles to prevent an equinus deformity. In diabetic patients, with adequate blood flow studies, rather than leave the infected wound open (the classic teaching), the author now prefers loose skin closure with the use of Gentamycin impregnated cement beads for a few days prior to formal wound closure. If left to heal by secondary intention, this process is painfully slow and often results in failure.
TRANS-METATARSAL OR MID-TARSAL AMPUTATION
This level of amputation is only rarely indicated following trauma (Fig. 7); it should not be used in dysvascular patients, but has a place in the management
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Figs 8 & 9 Mid-tarsalamputationafter crush injuryto foot.
Figs 10 & 11 Successfullongitudinalray amputationafter trauma.
PARTIAL F O O T AMPUTATION Partial foot amputation may be used following trauma (Figs 8 & 9) and success or failure is related to the degree of bone and soft tissue trauma proximal to the level of amputation, the severity of the initial injury and complications such as infection, delayed skin healing, late deformity and chronic pain 11(Fig. 4). In dealing with longitudinal ray amputations after trauma, acceptable procedures are: 1. individual rays I-V alone; 2. combined 2nd and 3rd, 3rd and 4th, or 4th and 5th rays. Unacceptable procedures are: 1. combined 1st and 2nd rays (Figs 10 & 11); 2. combined 2nd, 3rd and 4th, or 3rd 4th and 5th rays. In this situation, transmetatarsal amputation is the preferred procedure if possible. Larsson & Andersson 12 reported on amputations on some part of the foot (toe(s), metatarsal and tarsal levels) in 161 patients with gangrene from diabetes or
atherosclerosis. Sixty per cent healed soundly, but in over one-third of these cases at least one revision to a higher level on the foot had been required. It is important to point out that almost half of the patients spent over 3 months as an in-patient in hospital. Pinzur 13 reported on 29 ray resection amputations of the lower extremity in 25 dysvascular patients. Less than one-third healed without further amputation or ulceration.
INDICATIONS FOR SYME'S AMPUTATION 1. Following severe crush injuries of the foot, provided there is a healthy heel pad in the hope of preventing multiple surgical procedures to the foot, which are usually unsuccessful in relieving pain and allowing adequate functio.n. 2. In the diabetic population, this procedure has been popularized by Wagner, 2 who insists on an anklebrachial Doppler ratio of more than 0.45. As noted earlier, these ratios may be artificially high in diabetics because of associated calcification of the
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Fig. 12 Techniqueof long posterior flap for transtibial amputation in dysvascularpatients.
Fig. 13 Successfultrans-tibial amputation. lower limb vessels. Hunter 7reported wound healing at 3 months in only 15 out of 54 (28%) Syme's amputations for dysvascular patients (diabetic and non-diabetic). McElwain TM reported on 35 Syme's amputations after trauma. Twenty-four out of thirty- five (68%) were rated good, although many patients complained of stump pain. The majority of this group returned to work after the injury, but only 50% were able to bear weight on the stump without a prosthesis. They suggested that Syme's amputation cannot be recommended in dysvascular limbs, because of the high failure rate. Laughlin 15 reported a series of 52 diabetic patients treated with Syme's amputation for forefoot gangrene with reference to the predictive value of posterior tibial artery Doppler examination. When there was a normal posterior tibial artery pulse or a triphasic waveform, 26 out of 29 (90%) patients achieved a healed wound suitable for prosthetic wear. Only 13 out of 23 (57%) patients achieved a healed wound when there was either no posterior tibial artery palpable or a monophasic waveform. I personally feel that Syme's amputation should rarely be used for the dysvascular limb in the absence of diabetes, and I prefer a trans-tibial amputation to a Syme's amputation indysvascular patients because:
1. in our own series, the failure rate is unacceptable in the dysvascular group; 2. the surgeon's slow 'learning curve' phenomenon; how many procedures do you do per year? 3. there are too many problems with the heel pad, especially with diabetic peripheral neuropathy; 4. the cosmetic appearance is poor in females; 5. few patients actually perform end weight-bearing with or without the prosthesis; 6. although oxygen consumption and gait velocity is superior after Syme's amputation, when compared to trans-tibial amputation, the figures are not clinically significant in the dysvascular patient; 7. the number and quality of prosthetic components for trans-tibial amputees are superior to those available for a Syme's amputee.
BELOW KNEE AMPUTATION (TRANS-TIBIAL) Trans-tibial amputation is occasionally necessary following severe trauma, but is the level of choice for the majority of dysvascular patients (diabetic or non-diabetic) (Figs 12 & 13). I prefer a long posterior myofasciocutaneous flap in dysvascular patients but sagittal flaps or the 'skew flap' may be used after traumaJ The usual indications for transtibial amputation 16are: 1. necrosis or gangrene of the foot; 2. intolerable rest pain where vascular reconstruction is impossible or has failed; 3. chronic venous ulcers or deep burns of the foot or lower leg which have not healed after standard treatment; 4. severe fixed deformities of the foot combined with an insensate foot, preventing adequate weightbearing (failed limb salvage after trauma or Charcot type foot with chronic osteomyelitis and ulceration).
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Current Orthopaedics the volume of the stump before and after dialysis, and because of general ill health from medical problems; 4. following significant trauma to the lower limb, when a trans-tibial amputation is thought to be impossible because of a short bony stump (less than 5 cm to 6 cm) and inadequate skin and muscle coverage as a result of a degloving injury of the lower limb (Fig. 14). A trans-tibial stump may be covered with muscle and skin grafted at a later date, but split skin grafting is of no value after a failed through knee disarticulation.
Fig. 14 Bilateral through knee disarticulation 30 years after electric burns.
Contraindications to trans-tibial amputation
1. Necrosis or gangrene up to and including the level of the knee joint. 2. Fixed flexion of the knee joint of more than 20 degrees and more than 30 degrees at the hip joint. 3. A patient, who is already wheelchair dependent, from a contralateral through knee or transfemoral amputation is unlikely to benefit from a trans-tibial amputation and will be unable to use a trans-tibial prosthesis. 4. Senility and marked spasticity with a past history of prolonged custodial care and social dependence. 5. Significant arthritis of the knee joint. Bowker ~7analysed eight reported series with a total of 942 patients. Seventy per cent healed primarily and 16% secondarily, for a total healing rate of 86% and a failure rate of 14%. He also reviewed 13 papers between 1943 and 1987, and noted a 74% trans-tibial prosthetic usage with a range of 31% to 100%.
THROUGH KNEE DISARTICULATION
The indications for through knee disarticulation are: 1. a dysvascular patient who is already wheelchair dependent and who is suitable from vascular studies for a trans-tibial amputation may be better served by a through knee disarticulation, to avoid a short flexed trans-tibial stump with ulceration at the tip of the residual limb. The greater length of lower limb preserved when compared to a trans-femoral amputation will allow more control and comfort in the wheelchair and facilitate transfers; 2. patients with peripheral vascular disease who require a lower limb amputation, but who have significant arthritis of the knee joint; 3. patients on renal dialysis, who are unlikely to be prosthetic users because of constant changes in
Jensen 18 reports favourably on through knee disarticulation because of: (1) reduced mortality at one year when compared with trans-femoral amputation; (2) better prosthetic fitting, prosthetic use and function when compared to a trans-femoral amputation. Jensen 19 also pointed out that a failed trans-tibial amputation cannot be revised to a through knee disarticulation, and must be revised to a trans-femoral amputation, if minor revision is not possible. The traditional aversion to through knee disarticulation includes: 1. 2. 3. 4.
poor cosmesis especially in the female patient; poor function; lack of an available, suitable prothesis; similar oxygen consumption levels when compared to trans-femoral amputees. 19
Gibson 2° reported on 32 through knee disarticulations following trauma. Seventeen out of thirty-two (53%) patients were unlimited community ambulators, and 80% of patients were satisfied with both cosmesis and function. This may be related to the fact that in our unit the majority of patients were young males.
INDICATIONS FOR ABOVE KNEE AMPUTATION (TRANS-FEMORAL)
Indications for trans-femoral amputation are: 1. severe trauma of the lower limb with extensive damage to bone, joint, skin, muscle, nerves and blood vessels, often at multiple levels, when limb salvage has failed or appears to be unrealistic at the initial surgery - on occasion, split skin grafts may be used over the muscle flaps, with a view to secondary tissue expansion at a later date; 2. dysvascular patients, with or without diabetes, where it is felt that amputation would not heal at the trans-tibial or through knee levels after review of the appropriate vascular studies, and who are not suitable for angioplasty or by-pass procedures; 3. after failure of amputation at the trans-tibial or through knee levels; 4. in the presence of a fixed flexion contracture of the knee joint of more than 20 degreees to 25 degrees,
Selection of level for lower limb amputation which does not correct itself Under spinal or general anaesthesia. Such patients are unsuitable for trans-tibial prosthetic fitting and usage, but nowadays through knee disarticulation should be considered in this small group of patients.
HIP DISARTICULATION
This is fortunately rarely necessary, except for tumours, but indications include: 1. extensive crush type injuries of the entire lower limb; 2. after failed trans-femoral amputation in dysvascular patients with or without diabetes.
SUMMARY
Selection of level of lower limb a m p u t a t i o n following t r a u m a or in dysvascular patients must be based on experience, and a broad knowledge of the early and late problems following a m p u t a t i o n and prosthetic fitting. Successful wound healing is i m p o r t a n t to achieve, so that the patient can be soon fitted with a prosthesis, and become involved in a rehabilitation p r o g r a m with the emphasis on early return to work and/or the h o m e environment. It is helpful if the surgeon concerned has some knowledge of the advantages and limitations of prosthetic use at the various levels in the lower limb - too much information in the past has been relayed by word of m o u t h or repeated ad nauseam in orthopaedic textbooks. After trauma, it is usually a young male patient who must cope with limited function, loss of body image, difficult relationships with friends and loved ones leading to changes in their pattern of life and future plans. The dysvascular patient, however, is running 'out of time'. Stewart 2~ reported a mean survival in peripheral vascular disease patients of only four years plus two months, when c o m p a r e d to the diabetic dysvascular patients of only three 'years plus eight months, after the amputation. I f a patient survives for more than three years, there is a high chance that the other limb will be lost during that period. Young diabetic patients without peripheral vascular disease present with significant problems from peripheral neuropathy, osteoarthropathy of the foot and ankle, retinal damage and kidney problems often requiring long-term dialysis. These patients have limited life expectancy and selection of the level of a m p u t a t i o n must take into consideration the necessity for early prosthetic fitting and rehabilitation. Diabetic patients with absent foot pulses should not be treated any differently from non-diabetics when the level of amputation is being considered. Similarly,
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elderly patients with athero sclerosis should be assumed to be diabetic, and this assumption should be verified by appropriate biochemical tests. Both groups should be intensively investigated in the hope that angioplasty or by-pass procedures may prolong limb survival if only for a limited period. There have been suggestions that the level of amputation and need for revision in dysvascular patients may be affected adversely by prior attempts at revascularization, but other studies fail to support this claim. 22,23 Unfortunately, one must be both realistic and pessimistic about prosthetic fitting and use, especially in trans-femoral amputees. In a recent publication] 4 the authors conclude that only 10% to 15% of dysvascular amputees achieved mobility around the home on their prosthesis, and only 5% rehabilitate well independent of their wheelchair. They emphasize that when amputation is inevitable, more consideration should be given to surgery that optimizes wheelchair rehabilitation. These findings must make a surgeon responsible for performing the amputation continually aware of the importance of preserving the knee joint in the elderly dysvascular patient. REFERENCES
1. McCollum P T, Walker M A. Major limb amputation for end stage peripheral vascular disease: levelselection and alternative options. In: BowkerJ H, ed. Atlas of Limb Prosthetics, 2nd edn. American Academy of Orthopadeic Surgeons. St Louis: C V Mosby, 1992 2. Wagner F W Jr. In: BowkerJ H, ed. Atlas of Limb Prosthetics, 2nd edn. American Academy of Orthopaedic Surgeons. St Louis: C V Mosby, 1992 3. Ng E K, BerbrayerD, Hunter G A. Belowknee amputation; pre-operativevascular assessmentand functional outcome (in Press) 4. Georgiadis G M, Behrens F F, Joyce M J, Earle A S, Simmons A L. Open tibial fractures with severe soft tissue loss. Limb salvage compared with below-the-kneeamputation. J Bone Joint Surg 1993; 75A: 1431-i441 5. Ingrain R R, Hunter G A. Revascularisation,limb salvage and/or amputation in severeinjuries of the lower limb. Current Orthopaedics 1993; 7:19-25 6. BurgessE M. Personal Communication 1973 7. Hunter G A. Results of minor foot amputations for ischemia of the lower extremityin diabetics and non-diabetics. Can J Surg 1975; 18:273-276 8. LittleJ M, Stephen M S, Zylstra P L. Amputation of the toes for vascular disease. Fate of the affectedleg. Lancet 1976; 2(7999): 1318-1319 9. WheelockF C. Transmetatarsal amputations and arterial surgery in diabetic patients. N Engl J Med 1961; 264:316 10. Pinzur M, Kaminsky M, Sage R, Cronin R, Osterman H. Amputations at the middle level of the foot. J Bone Joint Surg 1986; 68A: 1061-1064 11. Millstein S G, McCowan S A, Hunter G A. Traumatic partial foot amputations in adults. A long-term review. J Bone Joint Surg t988; 70B: 251-254 12. Larsson U, Andersson G B J. Partial amputation of the foot for diabetic or arteriosclerotic gangrene. J Bone Joint Surg 1978; 60B: 126-130 13. Pinzur M S, Sage R, SchwaeglerR Ray resection in the dysvascular foot. A retrospectivereview.Clin Orthop 1984; 191:232-234 14. McElwain J P, Hunter G A, English E. Syme's amputation in adults; a long-term review. Can J Surg 1985; 28(3): 203-205 15. Laughlin R T, Chambers R B. Syme'samputation in patients with severediabetes mellitus. Foot Ankle 1993; 14 (2): 65-70
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16. Hunter G A. Below knee (trans-tibial) amputation. Current orthopaedics 1993; 7:55 58 17. Bowker J H. Trans-tibial (below knee) amputation. Report ISPO Consenus Conference on Amputation Surgery. University of Strathclyde Scotland, October, 1990. Ed Murdoch G, Jacobs N A, Wilson A B Jr 1990; 10-25 18. Jensen J S. Life expectancy and social consequences of through knee amputation. Prosthet Orthot Int 1987; 7:113-115 19. Jensen J S (1994); Personal Communication 20. Gibson R, Gossier S, Hunter G A. Through knee disarticulation in trauma. Paper Presented to British Trauma Group Oxford England 1993
21. Stewart C P U, Jain A S, Ogston S A. Lower limb amputee survival. Prosthet Orthot Int 1992; 16:11-18 22. Hunter G, Holliday R Major amputation following vascular reconstructive procedures (including sympathectomy). Can J Surg 1978; 21:456458 23. Campbell W B, Johnston J A St, Kernick V F M, Rutter E A. Lower limb amputation: striking the balance. Ann R Coll Surg Engl 1994; 76:205-209 24. Houghton A D, Taylor P R, Thurlow S, Rootes E, McColl I. Success rates for rehabilitation of vascular amputees; implications for pre-operative assessment and amputation level. Br J Surg 1992; 79:753-755
Amputation
Selection of level for lower limb amputation
G. A. Hunter
The limb should then be examined with particular reference to:
INTRODUCTION Lower limb amputations in the dysvascular patient or following lower limb trauma should be performed at the most distal site compatible with wound healing and with 'suitable prosthetic fitting and rehabilitation in mind'. The selection of level of amputation of the lower limb should be based on a thorough history and physical examination of the patient followed, where necessary, by appropriate radiographic and vascular studies (Fig. 1).
1. the amount of rest pain; 2. the skin temperature and appearance on elevation and dependency of the limb; 3. the level of palpable pulses; 4. the quality of venous return; 5. muscle tenderness, particularly in the calf (this usually indicates severe ischaemia); 6. the extent of ulceration, necrosis and infection of the limb; 7. associated neuromuscular and musculoskeletal problems, e.g. hemiplegia and arthritis; 8. onset of the disease, whether it is acute (embolism), or chronic (thrombosis) with better collateral circulation.
GENERAL ASSESSMENT
In dysvascular cases, the entire patient should be reviewed with particular emphasis on:
The patient and relatives will insist on amputation at the most distal level, preserving all length possible, feeling in this way that the patient will manage better after the operation. Although their wishes must be respected, this policy may lead to 'a hit-and-miss procedure', resulting in one or more painful revision procedures and unnecessary increased local and systemic morbidity. Preoperative vascular measurements
1. the general medical and mental health of the patient (cognitive skills activity level and possible prosthetic use); 2. the morbidity and mortality rates of the proposed procedure; 3. the nutritional status is considered adequate if the serum albumin level is at least 3.5 gmdL, and if there is a total lymphocyte count of more than 1500 cells/mm3; 4. the status of the contralateral limb (when present); 5. the social situation of the patient; 6. the natural history of the amputee with respect to the prognosis, eventual function and independence, quality of life and possible or probable use of a lower limb prosthesis. G. Hunter MB FRCS FRCS (C), ConsultantOrthopaedic Surgeon, SunnybrookHealth SciencesCentre (SCIL),2075 BayviewAvenue,North York, Ontario M4N 3M5, Canada. Address correspondence to: G. Hunter
Fig. 1 Gangreneof medialforefoot.What levelof amputation?
239
240
Current Orthopaedics will depend on whether the arterial damage is above or below the knee; 2. the necessity for local or free flaps to cover bone in order to preserve length, although these flaps are usually covered by split skin grafts, which do not have normal sensation; 3. a knowledge of the long-term results of lower limb amputees with reference to comfort, prosthetic use, return to work and recreational activities. How many surgeons involved in trauma care regularly attend an amputee clinic to assess the results of their surgical treatment (Figs 3, 4 & 5)?
Fig. 2 TypeIII C fractureof the tibia requiringearlythroughknee disarticulation.
are more beneficial in predicting failure than in predicting success. There is considerable evidence to support the use of a Doppler ultrasonography cut-off range of 50 to 70 mmHg at the lower part of the thigh for deciding on whether or not to do a trans-tibial amputation. With this simple reference, many transfemoral amputations could be avoided, but there would be a few trans-tibial failures as a consequence. 1 The ankle-arm Doppler arterial pressure ratio of at least 0.45 (diabetics) and 0.35 (peripheral vascular disease) has been previously used as the gold standard, 2 but subsequent studies3 have indicated that this ratio is unreliable because of calcification of the lower limb arteries in diabetic patients. In this same study of trans-tibial amputations, transcutaneous oxygen pressures of at least 30 mmHg at the proposed site of amputation were a good indicator of successful healing, whereas that of 20 to 30 mmHg warrant more serious consideration. When the transcutaneous oxygen pressure is below 20 mmHg, this finding should contraindicate a trans-tibial amputation, and consultation with a vascular surgeon should be obtained in the hope that angioplasty or revascularization will be possible, thus permitting a more distal amputation. After trauma, there are many scoring systems available to predict salvage or amputation of the lower limb. There is little written about the selection of level of amputation in trauma, and even less about the eventual outcome and quality of life of the patient following early or delayed amputation, when compared with salvage of the lower limb, which may entail many costly procedures (bone grafts, free flaps or use of the Ilizarov technique).4 The author has previously published in this Journal a discussion of the absolute and relative indications for primary (0-7 days) amputation of the lower limb. 5 The selection of level of amputation must be influenced by such factors as: 1. local damage to skin, muscle, nerves, bone or joint with or without reparable damage to the major blood vessels of the lower limb (Fig. 2), and much
Severe lower extremity trauma usually occurs in young males and is often associated with lifethreatening injuries to the head, chest, spinal column and abdomen. The level of" amputation is usually determined by the injury itself; but there is little to be gained by 'conserving all length possible' if it is not combined with good surgical judgment as to the eventual functional outcome of the amputee with reference to a well healed stump, available prosthetic fitting and the level of function to be expected at work and at home. Early thorough wound debridement should be combined with delayed secondary closure and early post-operative prosthetic fitting and rehabilitation should be organized within a specialized unit.
AMPUTATION OF THE TOE(S) This procedure is commonly used after trauma (lawnmower, boat propeller and industrial accidents). Vascular supply is not usually a problem. Skin flaps should be generous to avoid tension. The wound should be left open initially and closed secondarily to reduce the incidence of infection. Skin grafts may be used on the dorsum of the foot, but skin grafts on the plantar aspect of the foot should be avoided if possible in this load-bearing surface. The toe(s) may be disarticulated at any of the joints, through the phalanges or removed along with the metatarsal heads where necessary to allow adequate skin healing. Subsequent fitting of modified footwear and a soft orthotic device, with or without a toe filler, should provide adequate function and enable the patient to return to work and full recreational activities. In dysvascular patients, Burgess 6 estimated that less than 5% of patients with gangrene of the toe(s) caused by athero-osclerosis will heal after simple toe removal alone. Hunter 7 reported the results of amputation of the toe(s) in 128 operations in dysvascular patients (diabetic and non-diabetic). Only 42 out of 128 (33%) healed at 3 months. The results suggested that diabetic patients with ischaemic feet (i.e. an absence of foot pulses) should not be treated any differently from non-diabetics when amputation is being considered. The results of removal of one or more toe(s) were enhanced if vascular reconstruction had
Selection of level for lower limb amputation
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Figs 3, 4 & 5 Poor surgicaljudgmentleadsto difficultieswithprostheticfitting.
Fig. 6 Auto-amputationof toe (s) maytake manymonths.
Fig. 7 Trans-metatarsalamputationafterlawnmowerinjuryto all toes.
been performed during the preceding month. Little8 reported that by 30 months from the time of toe amputation in vascular disease, 50% of the patients had lost the affected leg. By 42 months, almost threequarters had come to major amputation. Removal of the toe(s) is not therefore recommended in dysvascular patients, unless vascular surgery or angioplasty has been successful in improving the circulation to the foot prior to the amputation. There is a small but limited group of patients who should be allowed to undergo auto-amputation of their toe(s) in the presence of pure necrosis of the end of the toe(s) without significant infection. This process may take many months, and the patient should be warned of this prolonged convalescent period (Fig. 6).
of diabetic patients with gangrene or chronic osteomyelitis of the toes, provided vascular studies are satisfactory. In the largest reported series in the literature, Wheelock9 reported on healing in 213 out of 336 (63%) of transmetatarsal amputations in diabetic patients. Hunter 7 reported successful transmetatarsal amputation, i.e. wound healing at 3 months in 12 out of 26 (46%) procedures in dysvascular patients (diabetic and non-diabetic). Pinzur I° reported on 64 amputations performed at the middle level of the foot in 58 patients. Successful wound healing was reported in 81% of this group of patients. If the amputation was performed at the tarsometatarsal level, it was combined with percutaneous lengthening of the tendo Achilles to prevent an equinus deformity. In diabetic patients, with adequate blood flow studies, rather than leave the infected wound open (the classic teaching), the author now prefers loose skin closure with the use of Gentamycin impregnated cement beads for a few days prior to formal wound closure. If left to heal by secondary intention, this process is painfully slow and often results in failure.
TRANS-METATARSAL OR MID-TARSAL AMPUTATION
This level of amputation is only rarely indicated following trauma (Fig. 7); it should not be used in dysvascular patients, but has a place in the management
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Current Orthopaedics
Figs 8 & 9 Mid-tarsalamputationafter crush injuryto foot.
Figs 10 & 11 Successfullongitudinalray amputationafter trauma.
PARTIAL F O O T AMPUTATION Partial foot amputation may be used following trauma (Figs 8 & 9) and success or failure is related to the degree of bone and soft tissue trauma proximal to the level of amputation, the severity of the initial injury and complications such as infection, delayed skin healing, late deformity and chronic pain 11(Fig. 4). In dealing with longitudinal ray amputations after trauma, acceptable procedures are: 1. individual rays I-V alone; 2. combined 2nd and 3rd, 3rd and 4th, or 4th and 5th rays. Unacceptable procedures are: 1. combined 1st and 2nd rays (Figs 10 & 11); 2. combined 2nd, 3rd and 4th, or 3rd 4th and 5th rays. In this situation, transmetatarsal amputation is the preferred procedure if possible. Larsson & Andersson 12 reported on amputations on some part of the foot (toe(s), metatarsal and tarsal levels) in 161 patients with gangrene from diabetes or
atherosclerosis. Sixty per cent healed soundly, but in over one-third of these cases at least one revision to a higher level on the foot had been required. It is important to point out that almost half of the patients spent over 3 months as an in-patient in hospital. Pinzur 13 reported on 29 ray resection amputations of the lower extremity in 25 dysvascular patients. Less than one-third healed without further amputation or ulceration.
INDICATIONS FOR SYME'S AMPUTATION 1. Following severe crush injuries of the foot, provided there is a healthy heel pad in the hope of preventing multiple surgical procedures to the foot, which are usually unsuccessful in relieving pain and allowing adequate functio.n. 2. In the diabetic population, this procedure has been popularized by Wagner, 2 who insists on an anklebrachial Doppler ratio of more than 0.45. As noted earlier, these ratios may be artificially high in diabetics because of associated calcification of the
Selection of level for lower limb amputation
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Fig. 12 Techniqueof long posterior flap for transtibial amputation in dysvascularpatients.
Fig. 13 Successfultrans-tibial amputation. lower limb vessels. Hunter 7reported wound healing at 3 months in only 15 out of 54 (28%) Syme's amputations for dysvascular patients (diabetic and non-diabetic). McElwain TM reported on 35 Syme's amputations after trauma. Twenty-four out of thirty- five (68%) were rated good, although many patients complained of stump pain. The majority of this group returned to work after the injury, but only 50% were able to bear weight on the stump without a prosthesis. They suggested that Syme's amputation cannot be recommended in dysvascular limbs, because of the high failure rate. Laughlin 15 reported a series of 52 diabetic patients treated with Syme's amputation for forefoot gangrene with reference to the predictive value of posterior tibial artery Doppler examination. When there was a normal posterior tibial artery pulse or a triphasic waveform, 26 out of 29 (90%) patients achieved a healed wound suitable for prosthetic wear. Only 13 out of 23 (57%) patients achieved a healed wound when there was either no posterior tibial artery palpable or a monophasic waveform. I personally feel that Syme's amputation should rarely be used for the dysvascular limb in the absence of diabetes, and I prefer a trans-tibial amputation to a Syme's amputation indysvascular patients because:
1. in our own series, the failure rate is unacceptable in the dysvascular group; 2. the surgeon's slow 'learning curve' phenomenon; how many procedures do you do per year? 3. there are too many problems with the heel pad, especially with diabetic peripheral neuropathy; 4. the cosmetic appearance is poor in females; 5. few patients actually perform end weight-bearing with or without the prosthesis; 6. although oxygen consumption and gait velocity is superior after Syme's amputation, when compared to trans-tibial amputation, the figures are not clinically significant in the dysvascular patient; 7. the number and quality of prosthetic components for trans-tibial amputees are superior to those available for a Syme's amputee.
BELOW KNEE AMPUTATION (TRANS-TIBIAL) Trans-tibial amputation is occasionally necessary following severe trauma, but is the level of choice for the majority of dysvascular patients (diabetic or non-diabetic) (Figs 12 & 13). I prefer a long posterior myofasciocutaneous flap in dysvascular patients but sagittal flaps or the 'skew flap' may be used after traumaJ The usual indications for transtibial amputation 16are: 1. necrosis or gangrene of the foot; 2. intolerable rest pain where vascular reconstruction is impossible or has failed; 3. chronic venous ulcers or deep burns of the foot or lower leg which have not healed after standard treatment; 4. severe fixed deformities of the foot combined with an insensate foot, preventing adequate weightbearing (failed limb salvage after trauma or Charcot type foot with chronic osteomyelitis and ulceration).
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Current Orthopaedics the volume of the stump before and after dialysis, and because of general ill health from medical problems; 4. following significant trauma to the lower limb, when a trans-tibial amputation is thought to be impossible because of a short bony stump (less than 5 cm to 6 cm) and inadequate skin and muscle coverage as a result of a degloving injury of the lower limb (Fig. 14). A trans-tibial stump may be covered with muscle and skin grafted at a later date, but split skin grafting is of no value after a failed through knee disarticulation.
Fig. 14 Bilateral through knee disarticulation 30 years after electric burns.
Contraindications to trans-tibial amputation
1. Necrosis or gangrene up to and including the level of the knee joint. 2. Fixed flexion of the knee joint of more than 20 degrees and more than 30 degrees at the hip joint. 3. A patient, who is already wheelchair dependent, from a contralateral through knee or transfemoral amputation is unlikely to benefit from a trans-tibial amputation and will be unable to use a trans-tibial prosthesis. 4. Senility and marked spasticity with a past history of prolonged custodial care and social dependence. 5. Significant arthritis of the knee joint. Bowker ~7analysed eight reported series with a total of 942 patients. Seventy per cent healed primarily and 16% secondarily, for a total healing rate of 86% and a failure rate of 14%. He also reviewed 13 papers between 1943 and 1987, and noted a 74% trans-tibial prosthetic usage with a range of 31% to 100%.
THROUGH KNEE DISARTICULATION
The indications for through knee disarticulation are: 1. a dysvascular patient who is already wheelchair dependent and who is suitable from vascular studies for a trans-tibial amputation may be better served by a through knee disarticulation, to avoid a short flexed trans-tibial stump with ulceration at the tip of the residual limb. The greater length of lower limb preserved when compared to a trans-femoral amputation will allow more control and comfort in the wheelchair and facilitate transfers; 2. patients with peripheral vascular disease who require a lower limb amputation, but who have significant arthritis of the knee joint; 3. patients on renal dialysis, who are unlikely to be prosthetic users because of constant changes in
Jensen 18 reports favourably on through knee disarticulation because of: (1) reduced mortality at one year when compared with trans-femoral amputation; (2) better prosthetic fitting, prosthetic use and function when compared to a trans-femoral amputation. Jensen 19 also pointed out that a failed trans-tibial amputation cannot be revised to a through knee disarticulation, and must be revised to a trans-femoral amputation, if minor revision is not possible. The traditional aversion to through knee disarticulation includes: 1. 2. 3. 4.
poor cosmesis especially in the female patient; poor function; lack of an available, suitable prothesis; similar oxygen consumption levels when compared to trans-femoral amputees. 19
Gibson 2° reported on 32 through knee disarticulations following trauma. Seventeen out of thirty-two (53%) patients were unlimited community ambulators, and 80% of patients were satisfied with both cosmesis and function. This may be related to the fact that in our unit the majority of patients were young males.
INDICATIONS FOR ABOVE KNEE AMPUTATION (TRANS-FEMORAL)
Indications for trans-femoral amputation are: 1. severe trauma of the lower limb with extensive damage to bone, joint, skin, muscle, nerves and blood vessels, often at multiple levels, when limb salvage has failed or appears to be unrealistic at the initial surgery - on occasion, split skin grafts may be used over the muscle flaps, with a view to secondary tissue expansion at a later date; 2. dysvascular patients, with or without diabetes, where it is felt that amputation would not heal at the trans-tibial or through knee levels after review of the appropriate vascular studies, and who are not suitable for angioplasty or by-pass procedures; 3. after failure of amputation at the trans-tibial or through knee levels; 4. in the presence of a fixed flexion contracture of the knee joint of more than 20 degreees to 25 degrees,
Selection of level for lower limb amputation which does not correct itself Under spinal or general anaesthesia. Such patients are unsuitable for trans-tibial prosthetic fitting and usage, but nowadays through knee disarticulation should be considered in this small group of patients.
HIP DISARTICULATION
This is fortunately rarely necessary, except for tumours, but indications include: 1. extensive crush type injuries of the entire lower limb; 2. after failed trans-femoral amputation in dysvascular patients with or without diabetes.
SUMMARY
Selection of level of lower limb a m p u t a t i o n following t r a u m a or in dysvascular patients must be based on experience, and a broad knowledge of the early and late problems following a m p u t a t i o n and prosthetic fitting. Successful wound healing is i m p o r t a n t to achieve, so that the patient can be soon fitted with a prosthesis, and become involved in a rehabilitation p r o g r a m with the emphasis on early return to work and/or the h o m e environment. It is helpful if the surgeon concerned has some knowledge of the advantages and limitations of prosthetic use at the various levels in the lower limb - too much information in the past has been relayed by word of m o u t h or repeated ad nauseam in orthopaedic textbooks. After trauma, it is usually a young male patient who must cope with limited function, loss of body image, difficult relationships with friends and loved ones leading to changes in their pattern of life and future plans. The dysvascular patient, however, is running 'out of time'. Stewart 2~ reported a mean survival in peripheral vascular disease patients of only four years plus two months, when c o m p a r e d to the diabetic dysvascular patients of only three 'years plus eight months, after the amputation. I f a patient survives for more than three years, there is a high chance that the other limb will be lost during that period. Young diabetic patients without peripheral vascular disease present with significant problems from peripheral neuropathy, osteoarthropathy of the foot and ankle, retinal damage and kidney problems often requiring long-term dialysis. These patients have limited life expectancy and selection of the level of a m p u t a t i o n must take into consideration the necessity for early prosthetic fitting and rehabilitation. Diabetic patients with absent foot pulses should not be treated any differently from non-diabetics when the level of amputation is being considered. Similarly,
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elderly patients with athero sclerosis should be assumed to be diabetic, and this assumption should be verified by appropriate biochemical tests. Both groups should be intensively investigated in the hope that angioplasty or by-pass procedures may prolong limb survival if only for a limited period. There have been suggestions that the level of amputation and need for revision in dysvascular patients may be affected adversely by prior attempts at revascularization, but other studies fail to support this claim. 22,23 Unfortunately, one must be both realistic and pessimistic about prosthetic fitting and use, especially in trans-femoral amputees. In a recent publication] 4 the authors conclude that only 10% to 15% of dysvascular amputees achieved mobility around the home on their prosthesis, and only 5% rehabilitate well independent of their wheelchair. They emphasize that when amputation is inevitable, more consideration should be given to surgery that optimizes wheelchair rehabilitation. These findings must make a surgeon responsible for performing the amputation continually aware of the importance of preserving the knee joint in the elderly dysvascular patient. REFERENCES
1. McCollum P T, Walker M A. Major limb amputation for end stage peripheral vascular disease: levelselection and alternative options. In: BowkerJ H, ed. Atlas of Limb Prosthetics, 2nd edn. American Academy of Orthopadeic Surgeons. St Louis: C V Mosby, 1992 2. Wagner F W Jr. In: BowkerJ H, ed. Atlas of Limb Prosthetics, 2nd edn. American Academy of Orthopaedic Surgeons. St Louis: C V Mosby, 1992 3. Ng E K, BerbrayerD, Hunter G A. Belowknee amputation; pre-operativevascular assessmentand functional outcome (in Press) 4. Georgiadis G M, Behrens F F, Joyce M J, Earle A S, Simmons A L. Open tibial fractures with severe soft tissue loss. Limb salvage compared with below-the-kneeamputation. J Bone Joint Surg 1993; 75A: 1431-i441 5. Ingrain R R, Hunter G A. Revascularisation,limb salvage and/or amputation in severeinjuries of the lower limb. Current Orthopaedics 1993; 7:19-25 6. BurgessE M. Personal Communication 1973 7. Hunter G A. Results of minor foot amputations for ischemia of the lower extremityin diabetics and non-diabetics. Can J Surg 1975; 18:273-276 8. LittleJ M, Stephen M S, Zylstra P L. Amputation of the toes for vascular disease. Fate of the affectedleg. Lancet 1976; 2(7999): 1318-1319 9. WheelockF C. Transmetatarsal amputations and arterial surgery in diabetic patients. N Engl J Med 1961; 264:316 10. Pinzur M, Kaminsky M, Sage R, Cronin R, Osterman H. Amputations at the middle level of the foot. J Bone Joint Surg 1986; 68A: 1061-1064 11. Millstein S G, McCowan S A, Hunter G A. Traumatic partial foot amputations in adults. A long-term review. J Bone Joint Surg t988; 70B: 251-254 12. Larsson U, Andersson G B J. Partial amputation of the foot for diabetic or arteriosclerotic gangrene. J Bone Joint Surg 1978; 60B: 126-130 13. Pinzur M S, Sage R, SchwaeglerR Ray resection in the dysvascular foot. A retrospectivereview.Clin Orthop 1984; 191:232-234 14. McElwain J P, Hunter G A, English E. Syme's amputation in adults; a long-term review. Can J Surg 1985; 28(3): 203-205 15. Laughlin R T, Chambers R B. Syme'samputation in patients with severediabetes mellitus. Foot Ankle 1993; 14 (2): 65-70
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16. Hunter G A. Below knee (trans-tibial) amputation. Current orthopaedics 1993; 7:55 58 17. Bowker J H. Trans-tibial (below knee) amputation. Report ISPO Consenus Conference on Amputation Surgery. University of Strathclyde Scotland, October, 1990. Ed Murdoch G, Jacobs N A, Wilson A B Jr 1990; 10-25 18. Jensen J S. Life expectancy and social consequences of through knee amputation. Prosthet Orthot Int 1987; 7:113-115 19. Jensen J S (1994); Personal Communication 20. Gibson R, Gossier S, Hunter G A. Through knee disarticulation in trauma. Paper Presented to British Trauma Group Oxford England 1993
21. Stewart C P U, Jain A S, Ogston S A. Lower limb amputee survival. Prosthet Orthot Int 1992; 16:11-18 22. Hunter G, Holliday R Major amputation following vascular reconstructive procedures (including sympathectomy). Can J Surg 1978; 21:456458 23. Campbell W B, Johnston J A St, Kernick V F M, Rutter E A. Lower limb amputation: striking the balance. Ann R Coll Surg Engl 1994; 76:205-209 24. Houghton A D, Taylor P R, Thurlow S, Rootes E, McColl I. Success rates for rehabilitation of vascular amputees; implications for pre-operative assessment and amputation level. Br J Surg 1992; 79:753-755