An overview is provided of the following aspects of partial foot amputations and disarticulations: 1) their advantages and limitations; 2) common causal conditions leading to ablations within the foot; 3) he indications for and contraindications to these procedures; 4) suggested surgical techniques for each specific level; 5) the anticipated effect on barefoot walking of each level and some commonly prescribed prosthetic, orthotic, or shoe wear solutions. Reasons for acceptance or rejection of these levels on the part of surgeons, patients, and prosthetists are discussed. Amputations and disarticulations within the foot offer the advantage of direct weight bearing, which is especially important to older individuals. Because most of these procedures are done in diabetic and/or dysvascular persons, who are at considerable risk of a contralateral amputation within 5 years, preservation of a partial foot is vital to the maintenance of independent ambulation if the amputation of the second limb must be at the transtibial level or higher. However, for younger trauma victims, a partial foot ablation may not be acceptable because of the loss of load-bearing capacity and stability, especially at the more proximal levels, which makes the restoration of effective running gait difficult or impossible with currently available prostheses and orthoses. Additional research and development are needed to provide devices that will make these levels functional for all age groups. (J Prosthet Orthot. 2007;Proceedings:P62–P76.)
Surgeons who treat foot disorders will inevitably encounter a patient who requires an amputation of part or all of the foot. Most frequently, this need arises emergently as a result of infection, ischemia, or trauma or some combination thereof. This article serves as an introduction to this field of surgical care, which has become a more common part of surgical practice during the past few decades as surgeons have begun to appreciate the functional benefits that retention of a portion of the foot offers many individuals. Advances in material science and design have resulted in greatly improved partial foot prostheses, orthoses, and shoe wear for these levels.
Until the latter half of the 20th century, partial foot amputations and disarticulations were done almost exclusively for trauma sustained in battle or industrial accidents. Prior to that time, whenever dry gangrene caused by critical limb ischemia or wet gangrene from infection occurred, the accepted treatment was a major lower limb amputation. The rationale was to amputate at a level where primary healing could safely be anticipated. For this reason, more often than not, the transfemoral level was chosen. Because failure of primary healing posed a very real danger of death during that era, the emphasis was on survival, not functional rehabilitation. With convergent advances in fields such as tissue oxygenation evaluation, vascular and amputation surgery techniques, antibiotic therapy, and wound healing, the surgeon now has the opportunity to consider the foot, rather than the tibia or femur, as the level of choice for amputation in selected cases of trauma, ischemia, or diabetic infection (wet gangrene) with or without peripheral vascular disease.1
Partial foot ablations offer several advantages over more proximal levels. With at least the hindfoot remaining, a person can continue to bear weight directly on the residual foot with proprioceptive feedback along normal neural pathways. This is in sharp contrast to the transtibial amputee, who must interpret feedback from previously nonweight-bearing tissues. Walking function ranges from nearly normal gait following single ray (toe and metatarsal) amputation or amputation of all toes at the metatarsophalangeal (MTP) joints, to significant impairment in the case of midtarsal (Chopart) disarticulation. Barefoot walking after ablation at any foot level proximal to the metatarsal heads is markedly impaired because the load-bearing capacity, stability, and dynamic function of the foot are reduced.2 Restoration of more complex activities important to younger patients, such as running, remains problematic. However, in elderly or debilitated patients, retention of even the hindfoot can preserve far greater independence in both transfer activities and ambulation without a prosthesis than will either a transtibial or transfemoral amputation, which require a prosthesis for bilateral weight bearing. In addition, partial foot amputations and disarticulations result in the least alteration of body image, often requiring only shoe modifications or a limited orthosis, prosthesis, or "prosthosis."
Currently, the most common indication for these procedures is infection with tissue necrosis in diabetic persons. With the combination of sensory neuropathy and tightly fitting shoe wear, the skin over any bony prominence can develop an ulcer that eventually penetrates the bones and joints beneath, followed by infective (wet) gangrene.
Ischemia of the foot may result from a variety of conditions, including peripheral vascular disease with or without diabetes mellitus, showers of microemboli after cardiac surgery, arteritis associated with lupus erythematosus and other collagen diseases, peripheral vasoconstriction following vasopressor treatment for severe hypotension, cryoglobulinemia, and frostbite. Cigarette smoking can be an aggravating factor in all these situations.
The most common traumas today resulting in partial foot ablations are those from moving machinery (e.g., lawn mowers) or motor vehicle accidents (Figure 1 ). Others include crush injuries with or without fractures, degloving injuries that remove a significant portion of weight-bearing skin, or lacerations that devitalize the forefoot. Less common are thermal injuries, which include frostbite and burns, the latter most often associated with diabetic sensory neuropathy or electrical injury. Rarely, a congenital abnormality of the foot may require surgical correction to allow the fitting of shoes.
An important contraindication may become apparent after a thorough discussion with the patient regarding the functional pros and cons of these levels. If the patient wishes to return to activities involving running, a transtibial level may be preferable. There are also relative contraindications, some with strong behavioral overtones, such as nicotine addiction or poor plasma glucose control. Although these factors, as well as nutritional deficiencies, such as low serum albumin, should not dictate level selection, they do deserve adequate preoperative evaluation and assiduous correction. In addition, tissue oxygen perfusion is often a major determinant of level. If it is inadequate for healing as determined by transcutaneous oxygen measurements (less than 30 mm Hg), consultation with a vascular surgeon is indicated. Arterial flow can often be improved with vessel recanalization or bypass, or compensated for by postoperative hyperbaric oxygen therapy, allowing a distal amputation to be performed.
If the criteria for level selection and wound healing are met, no amputation level in the foot need be excluded on the basis of etiology. Of course, the procedure must be done proximal to a malignant tumor, an irreparably damaged body part, or gangrenous tissue. The bony level selected must match the skin available for coverage in both length and quality. A lack of skin in relation to bone, therefore, requires further shortening of bone to a level where this criterion can be met.3 This will ensure both closure without tension and placement of scar tissue away from areas of direct weightbearing and shear forces. When this principle is ignored in an attempt to save length at any cost, the result for the patient can be prolonged morbidity and excessive delay in returning to maximum functional status (Figure 2 ,Figure 3 ,Figure 4 ).
To absorb the shear and pressure forces generated during gait, the soft-tissue envelope must be mobile. Although muscle tissue is an integral part of the soft-tissue envelope in more proximal amputations, it is not available at most distal levels. In the foot, ideal flaps are formed of plantar skin, subcutaneous tissue, and investing fascia. This multilayer soft tissue construct will provide mobility over the underlying bone, minimizing the adherence of skin to bone. Conversely, coverage with split-skin grafts should be avoided on the distal, lateral, and plantar surfaces of the residuum4 (Figure 5 ). Nonetheless, split-skin grafts placed on well-granulated dorsal bony surfaces can last indefinitely with reasonable care (Figure 6 ). Proper contouring of bone ends will prevent damage to the soft-tissue envelope from within wherever it is compressed between bone and the prosthesis, orthosis, or shoe.
Salvage of a useful portion of the foot whenever possible is strongly indicated in diabetic and/or dysvascular persons. Statistically, they are at considerable risk of amputation of the opposite leg within 5 years (references). Therefore, preservation of a partial foot at the first operation is vital to the maintenance of independent ambulation, especially if the amputation of the second limb must be at the transtibial level or higher. Longitudinal (ray), rather than transverse, amputation should be the goal whenever technically and functionally feasible. By only narrowing the foot, rather than shortening it, loss of loadbearing capacity and stability are minimized, and postoperative shoe fitting is simplified.
Postoperative casting is recommended for all but minor partial foot procedures to support and protect the wound. Edema-producing foot dependency is discouraged, and weight bearing is not allowed until the wound is solidly healed. To prevent equinus contracture of the ankle joint in foot ablations proximal to the MTP joints, postoperative casting in slight dorsiflexion for 3 to 4 weeks is recommended. By thus encouraging atrophy of the more massive ankle plantar flexors, immobilization may result in a more muscle-balanced residual foot. All casts should be changed weekly for wound inspection.
Following interphalangeal disarticulation of the great toe, the remaining proximal phalanx will aid with balance and may result in a better gait than after disarticulation at the MTP joint. The clinical assumption is that this is due to preservation of useful toe lever length, the flexor hallucis brevis complex, including the sesamoids and, therefore, the windlass mechanism (Figure 7 ). When a more radical resection of the proximal phalanx is required, Wagner5 recommends leaving just its base, to keep both the sesamoids and the plantar fat pad beneath the metatarsal head, although the windlass mechanism is lost because the activating toe lever is gone.
The MTP joint is the next common site in the great toe. After division of the flexor hallucis brevis insertions on the proximal phalanx, the sesamoid bones will retract just proximal to the metatarsal head and may produce troublesome bony prominences. For this reason, the sesamoids should be excised and the crista removed with a rongeur if it is prominent. If toes three or four alone are disarticulated, the adjacent ones will tend to close the gap and restore a good contour to the distal forefoot for shoe fitting (Figure 8 ). Leaving a lesser toe isolated by removing toes on either side will increase its susceptibility to injury (Figure 9 ).
Disarticulation of the second toe at the MTP joint, by removing lateral support from the great toe, may result in a hallux valgus (bunion) deformity. The skin over this bony prominence may then ulcerate, especially in an insensate foot (Figure 10 ). To avoid this possibility, it is often better to do a second ray amputation, dividing the metatarsal through its proximal metaphysis. The first and third metatarsals will then usually approximate each other, narrowing the foot, resulting in a good cosmetic and functional outcome (Figure 11 ).
Occasionally, dry gangrene may occur in all five toes because of occlusion of their end arteries, without significant change in perfusion proximally. In this case, disarticulation of all five toes with primary coverage of the metatarsal heads is feasible, provided that the dorsal and plantar incisions are both made as far distally as possible in the web spaces (Figure 12 ).
Walking function after great toe disarticulation at the MTP joint may be altered because of loss of the first ray's role in the final transfer of weight during late stance phase, as well as some possible decrease in foot stability medially due to loss of the windlass mechanism. This effect of great toe loss was studied by Mann et al.6 in 10 patients (average age, 23 years) who had undergone pollicization of the great toe for loss of a thumb. They found a shift in the endpoint of progression of the moving center of plantar pressure during stance from the second metatarsal head to the third. In this group, clinical complaints after an average of 3 years were minimal, except for difficulty in making rapid movements requiring intact medial foot stability and great toe flexion during active sports. Following MTP disarticulation of all five toes, forefoot stability and gait while barefoot clinically appear to be better than after transmetatarsal amputation, presumably because of retention of the load-bearing capacity of the metatarsal heads.
During a ray amputation, the toe and a variable portion of its metatarsal are excised. In regard to the first (medial) ray, the metatarsal shaft should be left as long as possible to aid in effective elevation of the medial arch by a custom-molded insert (Figure 13 ). The usual indication for a first ray amputation is an ulcer beneath the first metatarsal head that has penetrated the MTP joint capsule. Often, only a portion of the head need be removed with the great toe to eradicate the infection, leaving all uninfected portions of the head and shaft. The bone should be beveled on the plantar aspect to avoid an area of high pressure during latter stance phase.
Single amputations of rays two, three, or four will only moderately affect the width of the forefoot. Resection is best carried out through the proximal metaphysis just distal to the intersection of the base of the involved ray with those of the adjacent metatarsals, leaving the tarsometatarsal joints intact (Figure 14 ). For a fifth metatarsal amputation, the shaft should be transected obliquely with an inferolateral-facing facet, leaving the uninvolved half to three-quarters of the shaft to preserve forefoot width and retain the insertion of the peroneus brevis.
In cases of extensive forefoot infection, multiple rays may be involved. Removal of two or more medial rays is a poor choice, both functionally and cosmetically, as is removal of two or more central rays. If two or more lateral rays must be excised, the metatarsals should be divided obliquely, with each affected one being cut somewhat longer as one progresses toward the first ray (Figure 15 ). If all but the first ray are involved, it can be left as the only complete one (Figure 16 ). With good pedorthic fitting, this is preferable to a transmetatarsal amputation.5,7,8
An intact medial column is essential to proper foot balance during both stance and forward progression. The effectiveness of orthotic restoration of the medial arch following a first ray amputation will depend on the length of shaft preserved. With single lesser ray amputations, only the width of the forefoot is reduced, preserving good rollover function and overall foot balance during terminal stance, as well as good cosmesis. Removal of several lateral rays, done as conservatively as possible, can retain both rollover function and full foot length in a shoe.
This should be considered when two or more medial rays must be amputated. To provide maximum surface area on the foot for secure suspension of a shoe, it is important to save as much metatarsal shaft length as can be covered with good plantar skin, avoiding the use of fragile split-skin graft distally and plantarly (Figure 17 ). To assist in obtaining this goal and to assure distal coverage of the metatarsal shafts with durable skin, both plantar and dorsal transverse skin incisions are made at the base of the toes. Residual dorsal defects can be easily managed with split-skin grafts with good assurance that they will not break down later, provided proper footwear is consistently used. Again, to help preserve length, the metatarsal cuts should begin medially, if possible within the cancellous bone of the first metatarsal head. The 15-degree transverse angle that parallels the MTP joints and "toe break" of the shoe should be reproduced to assist forward progression. Plantar beveling of the metatarsal shafts will help reduce distal plantar pressures during late stance. Application of a well-padded short leg cast, in slight dorsiflexion, on the operating table will prevent postoperative equinus deformity. If no passive dorsiflexion is present before surgery, a percutaneous fractional Achilles tendon lengthening is indicated to reduce distal pressures under the metatarsal shafts. If "drop foot" is secondary to nerve trauma, transfer of a posterior muscle-tendon unit may be added for its tenodesis effect, with an ankle-foot orthosis (AFO) fitted after wound healing.
Barefoot walking after transmetatarsal amputation is impaired because of loss of the weight-bearing metatarsal heads and elimination of forefoot pronation and supination during gait.2 A rigid rocker bottom (RRB) shoe may help reduce distal pressure and shear from a flexible-soled shoe wrapping around the end of the residual foot. Although these forces may be just a matter of discomfort to a traumatic amputee, for a person with an insensate or dysvascular residuum, they may cause ulceration, resulting in reamputation to a more proximal level. A distal filler will maintain the shape of the toebox. Some patients (i.e., those unconcerned with cosmesis) may choose a custom-made short shoe, but this fitting, due to the shortened forefoot lever arm, will result in an asymmetrical "drop-off" gait. Another option for a short transmetatarsal amputation is an ankle-foot orthosis (AFO) with an anterior shell to provide improved stability and balance. A number of inframalleolar prostheses for this level have been successfully fitted.
This procedure, first described by Lisfranc in 1815,9 is often used in cases of trauma and selected cases of foot tumor but is also applicable to certain cases of infection. Patients selected must be good candidates for control of infection at this level so as not to lose the opportunity for a successful Syme ankle disarticulation. To help maintain a balanced residual foot, the insertions of the peroneus brevis, peroneus longus, and anterior tibial tendons are preserved. Careful dissection will spare the proximal insertions of the peroneus longus and anterior tibial tendons on the plantar aspect of the medial cuneiform. The distal insertion slips of these tendons on the first metatarsal base can also be dissected and sutured to the proximal slips as reinforcement. The first, third, and fourth metatarsals are disarticulated, whereas the "keystone" base of the second metatarsal should be left in place to help preserve the proximal transverse arch. A portion of the fifth metatarsal base is also retained to preserve the insertion of the peroneus brevis tendon. With a significant loss of forefoot lever length, the massive triceps surae muscles can easily overpower the relatively weaker dorsiflexors, leading to equinus contracture. This deformity can be avoided by doing a primary percutaneous fractional Achilles tendon lengthening, followed by application of a cast with the foot in a plantigrade or slightly dorsiflexed position. Another method in lieu of Achilles tendon lengthening is cast immobilization of the residual foot in dorsiflexion for 3 to 4 weeks to hasten atrophy of the triceps surae (Figure 18 ).
This level represents a major loss of forefoot length with a corresponding decrease in barefoot walking function. In many instances, it is necessary to provide an intimately fitting prosthesis or orthosis that extends well onto the skin. However, in some cases sufficient suspension surface may be available to allow fitting of an inframalleolar device.
This disarticulation is through the talonavicular and calcaneocuboid joints. As with the Lisfranc level, it is most useful in trauma and selected cases of foot tumor. It is rarely applicable to extensive diabetic foot infections because of proximity to the heel pad. At the time of disarticulation, all ankle dorsiflexors are divided. Without restoration of dorsiflexor function and weakening of the plantar flexors, severe equinus deformity from myostatic contracture of the unopposed triceps surae is inevitable. Weight bearing in equinus becomes painful as it shifts from the heel pad to the distal talus and calcaneus. Active dorsiflexion can be restored to this extremely short residual foot by attachment of the anterior tibial tendon to the talus, either through a drill hole in the talar head or with sutures or staples to a groove in the distal aspect of the head.10 To further restore relative balance between dorsiflexors and plantar flexors, the author has found it effective to remove 2 to 3 cm of the Achilles tendon, rather than lengthen it. This is done through a separate longitudinal incision, leaving the sheath of the tendon in place to allow rapid reconstitution of the tendon at its new length. Removal of the sharp anteroinferior corner of the calcaneus is also recommended. If the bone is not properly contoured and equinus deformity occurs, this corner is apt to cause pain during stance and gait because some of the distal surface becomes weight bearing.
A cast should be applied with the hindfoot in slight dorsiflexion for about 6 weeks to prevent equinus contracture of the hindfoot and allow secure healing of the transferred tendon to the talus. Alternatively, Baumgartner11 recommends postoperative external fixation of Chopart disarticulations to prevent equinus deformity. Nonetheless, he anticipates what he considers inevitable equinus contracture by reshaping the distal talus and calcaneus to allow less painful anterior weight bearing in equinus (Figure 19 ).
Marquardt12 suggests that anterior tibial tendon transfer to the talus alone is insufficient because the transferred muscle elevates only the talus while the continued plantar flexion force on the calcaneus by the triceps surae produces separation and instability of the subtalar joint over time. He has developed a tenomyoplastic operation that restores some dorsiflexion power to both bones. The anterior tibial and extensor hallucis longus tendons are placed in separate grooves in the distal talar head, while the common toe extensors are placed in a groove in the anterior calcaneus. With the hindfoot held in dorsiflexion, the tendons are sutured to the plantar capsular and fascial structures12 (Figure 20 ). The hindfoot is casted in dorsiflexion until the tenodeses are sound.
If weight bearing becomes painful because of severe equinus, Baumgartner11 recommends Z-lengthening of the Achilles tendon and wedge resection and arthrodesis of the subtalar joint with transfer of the anterior tibial tendon to the lateral border of the residuum. The heel pad again becomes plantigrade, and the vertical clearance for a prosthetic foot is increased by 1 to 2 cm11 (Figure 21 ). The author has treated several cases of painful equinus gait following Chopart disarticulation in which no dorsiflexors were known to have been reattached. Active dorsiflexion with restoration of comfortable heel pad weight bearing was obtained by excision of 2 to 3 cm of Achilles tendon with cast immobilization in maximum available dorsiflexion for 3 to 4 weeks. This simple salvage procedure, recommended by Burgess,8 avoids revision to a Syme or higher level (Figure 22 ).
Because a prosthesis for this level blocks both ankle and subtalar motion without necessarily preventing deformity, some authors have recommended arthrodesis of both the subtalar and ankle joints after Chopart disarticulation. The advantages cited are prevention of equinus deformity by ankle fusion and prevention of progressive talocalcaneal instability by subtalar fusion.13,14
With preservation of full leg length and a stable heel pad, the Chopart patient can walk with direct end bearing for short distances without a prosthesis, although this short residuum has no inherent rollover function. An intimately fitted rigid-ankle prosthesis or orthosis and a shoe with a rigid rocker bottom are commonly provided.
Despite the direct weight-bearing, proprioceptive, and cosmetic advantages of partial foot amputations and disarticulations, their full potential has yet to be realized. There are many reasons for this disparity. In some surgical and prosthetic circles, they have a reputation for poor wound healing and development of equinus contracture, followed by painful prosthetic gait and ulcers. Many wound healing problems can be traced to a failure to select patients for these procedures who have adequate tissue oxygen perfusion, sufficient mobile, durable skin for wound closure without tension, and uncontaminated tissues. Regarding the last factor, the surgeon should regard all amputations done for trauma or infection as contaminated. These wounds should be left open and redebrided as often as necessary until they have an abundance of healthy granulation tissue. At this point, they can be more safely excised and closed. Equinus contracture may be due caused by a failure to immobilize the ankle in maximum dorsiflexion until the wound is soundly healed. Failure can also result from the desire to "save limb length at any cost" on the part of the surgeon and patient.
There are biases of the surgeon and prosthetist that may determine how they present the options for amputation levels to the patient and family. These biases are based on their training, knowledge base, experience to date, and the skill set they possess. In fact, each of the several levels described has its own advantages and disadvantages. With regard to barefoot walking, the least impairment seems to be associated with toe or single ray loss. Nonetheless, when a forefoot injury or infection occurs, although there are several well-recognized levels of partial foot ablation, the transmetatarsal level may be the only one considered by the surgeon, even when a lesser procedure might adequately address the problem without loss of the load-bearing capacity and stability provided by the metatarsal heads.
From a surgical perspective, certain basic criteria must be met to ensure the greatest functional benefit from each level. These include maintenance of adequate bone length, proper contouring of bony elements where they interface with skin, and wound closure without tension with well-perfused, proportionate, mobile, and durable soft tissue. Preservation or restoration of ankle motion is another major goal to allow comfortable end bearing on a plantigrade heel pad. At the Lisfranc level, good surgical technique will leave the foot dorsiflexor and everters in place. However, after Chopart disarticulation, ankle dorsiflexion function must be restored by the transfer of dorsiflexor muscle-tendon units to the hindfoot.
All partial foot ablations proximal to the metatarsal heads should be totally enclosed in a well-padded cast on the operation table to protect the wound, control edema, and prevent equinus contracture. Foot dependency is avoided. Weekly cast changes will suffice because there is no need for daily wound inspection. If infection occurs, there will be systemic signs or unexpected drainage, at which point the cast is promptly removed and the wound evaluated.
An important part of postoperative management in these cases is compliance on the part of the patient. This includes avoidance of weight bearing until the wound is sound enough for suture removal, maintenance of adequate nutrition, avoidance of vasoconstrictors such as nicotine and caffeine, and tight control of plasma glucose levels by diabetics. Walking should be limited to the absolute minimum and the foot kept elevated whenever the patient is not walking to reduce the negative effect of edema on wound healing.
At the current stage of prosthetic design, partial foot amputations and disarticulations may not meet the needs of all patient populations equally well. For example, older individuals who may have poor balance or vision find that secure end-bearing ambulation is a distinct advantage. Many longterm diabetic persons have the same impairments because of insensate feet and retinopathy. Dysvascular amputees typically walk at one slow pace because of generalized cardiovascular disease. These groups and sedentary adults and children with traumatic amputations or congenital foot deficiencies generally do quite well with the devices currently available.
Younger adults with ablations for trauma can often benefit from in-depth counseling prior to a definitive procedure. They should meet with the surgeon, their prospective prosthetist, and one or more trained peer counselors matched for possible levels of amputation, their pretrauma activity level, age, and sex. If they wish to return to sports that require extensive running, they may be more satisfied with a long transtibial amputation or Syme ankle disarticulation than a partial foot ablation, given the difficulty of restoring running gait with currently available devices.
With convergent advances in wound healing, tissue oxygenation evaluation, and antibiotic therapy, as well as improvements in vascular and amputation surgery techniques, today's surgeons have the opportunity to consider the foot, rather than the tibia or femur, as the site of election for amputations resulting from a variety of traumatic, ischemic, or infectious conditions.
Amputations and disarticulations within the foot offer important advantages over more proximal levels, including direct weight bearing with proprioceptive feedback along normal neural pathways. Retention of even the hindfoot provides for greater independence without a prosthesis than higher levels, such as transtibial or transfemoral amputations, which require prostheses for walking. This is especially important for elderly patients who often have significant cardiopulmonary comorbidities and poor balance and who may face a future contralateral amputation. In addition, amputation levels within the foot result in the least alteration of body image, often requiring only shoe modifications or a limited orthosis or prosthesis for the more distal levels.
The disadvantages include variable loss of load-bearing capacity, stability, and dynamic function of the foot when the metatarsal heads have been removed. The loss of surface area available for secure suspension of a lower aspect prosthesis that would allow ankle motion in Lisfranc and Chopart disarticulations is sometimes problematic. For these reasons, younger patients who participate in running sports may find a transtibial amputation or Syme ankle disarticulation more functional for these activities. With additional research and development by the prosthetic and orthotic professions, it is anticipated that these limb-sparing procedures can become more applicable to all age groups and levels of activity.
Correspondence to: John H. Bowker, MD, 630 Solano Prado, Coral Gables, FL 33156; e-mail:
JOHN H. BOWKER, MD, is a professor emeritus in the Department of Orthopaedics and Rehabilitation of Miller School of Medicine at the University of Miami, Florida.