Fusion Podoplasty for the Management of Chronic Pedal Conditions in Seven Dogs and One Cat
Eight animals underwent fusion podoplasties for the treatment of chronic interdigital furunculosis (n=3), ectrodactyly (n=1), digit abnormalities associated with tendonectomy (n=1), redundant indertigital skin (n=1), conformational deformity (n=1), and necrotizing fasciitis of the paw (n=1). Median duration of bandaging was 14 days, and median duration of hospitalization was 5 days. Four dogs had dehiscence, which occurred at a mean time of 11 days after surgery. Clinical abnormalities necessitating podoplasty resolved in six animals and improved in two. Six animals had normal ambulation and two dogs had slight weight-bearing lameness after a median follow-up time of 29 mo. Fusion podoplasty may be recommended as a salvage procedure for the treatment of various chronic pedal diseases in dogs and cats.
Introduction
Fusion podoplasty is a surgical reconstructive procedure involving the removal of diseased intedigital skin tissues, which reportedly results in a functional, pain-free paw.1 Total fusion podoplasty (TFP) entails removal of the skin between digits and associated pads of the forepaw or hind paw. The phalanges and digital metacarpal/metatarsal pads are sutured in apposition to close the resulting skin wound defects.2 The primary indications for performing TFP are the management of dysfunction associated with chronic, fibrosing, interdigital pyoderma resistant to medical treatment or to resolve chronic digital flexor tendon severance.2,3 Partial fusion podoplasty (PFP) can also be performed when the condition necessitating podoplasty is confined to two adjacent digits, paw reconstruction following digit amputation, or for congenital deformities of the paw.1,4–7 The purpose of the current study is to report the results of fusion podoplasty in seven dogs and one cat. Several of these podoplasties were done for reasons previously unreported as indications for the procedure. Modifications of the surgical technique are also described.
Materials and Methods
Medical records of dogs and cats that underwent fusion podoplasty at the University of Florida's College of Veterinary Medicine Veterinary Medical Center between 1993 and 2009 were reviewed. Data retrieved from the records included signalment, history, clinical signs, abnormalities necessitating podoplasty, clinical pathology evaluations (including complete blood count and serum biochemistry analysis), cytology, dermatologic tests performed (including skin scrapes and allergy testing of skin), culture and sensitivity results, radiographic examinations, surgical treatments, duration of the surgical procedure, histopathology results, postoperative care, complications, and short- and long-term outcome. The fusion podoplasty procedure was classified as either a TFP if the second through fifth digits and the associated digital pads underwent fusion or a PFP if fusion was only performed between two adjacent digits. Long-term follow-up information was obtained by either re-examination or telephone communication with the owner or referring veterinarian.
Results
Signalment
Seven dogs and one cat that underwent fusion podoplasty entered the study. Breeds represented were the English bulldog (n=2) and one each of Pekingese, rat terrier, greyhound, Labrador retriever, Afghan hound, and a domestic shorthair. There were four male dogs (two of which were neutered) and three females (two of which were spayed). The cat was a spayed female. Median age at presentation was 30 mo (mean, 40.25 mo; range, 4–120 mo) and median weight was 17.95 kg (mean, 19.28 kg; range, 2.5–45 kg). Clinical data of the eight animals has been presented in Table 1.
CIF, chronic interdigital furunculosis; CM, castrated male; DSH, domestic shorthair; F, female; FP, forepaw; HP, hind paw; L, left; M, male; NA, not available; PFP, partial fusion podoplasty; R, right; SF, spayed female; TFP, total fusion podoplasty.
History and Clinical Signs
Three dogs (cases 1, 2, and 5) were presented with pododermatitis resistant to local treatment and systemic antibiotic therapy. All dogs with pododermatitis had erythematous lesions in the interdigital webs. Cases 1 and 5 had swellings or cysts in all interdigital webs, case 2 had ulcerated cysts in the interdigital web between the third and fourth digits, and case 3 had ulcerated cysts on the plantar surface of the paw. Case 5 also had ulcerated cysts, pad ulcers and fibrous tissue in both forepaws, and fused digital pads of the second and third digits, with an extra pad fused caudally to the fused digital pads in both forepaws. Case 2 showed pain and discomfort on palpation of the paw. Case 3 was admitted with a congenital deformity of the left forepaw and intermittent non-weight-bearing lameness exacerbated by exercise. In this case, the second and third digits of the left forepaw were not fused with the rest of the limb and the first phalanx of the second digit was curled under with a normal nail growing in a caudal direction. In addition, the left forelimb carpus had a valgus deformity, which had a limited range of motion on palpation. An extra nail also was also noted growing out of the lateral side of the third digit, and a callus had developed on the medial aspect of the metacarpus. The cat (case 4) presented with abnormalities associated with prior deep digital flexor tendonectomy of the left forepaw. Clinical examination showed overextension of the third and fourth digits of the left forepaw, creating a postural deformity. One dog (case 6) was admitted with redundant interdigital skin folds of both forepaws, with recurrent superficial abrasions and deep ulcerations (Figure 1). Case 7 was presented with a right hind paw deformity and an intermittent non-weight-bearing lameness ascribed to a possible trauma that incurred when the dog was a very young puppy. Clinical examination of this dog revealed that the distal phalanx of the third digit of the right hind paw was encroaching upon the adjacent digit, and was painful on palpation. The dog walked on the lateral aspect of its right hind paw, and had a callus on the weight-bearing aspect of the paw. Case 8 was presented with inflammation and necrosis of the left hind paw associated with a bite wound. Clinical examination of this dog revealed ulceration and necrosis of the left hind paw on the dorsal, plantar, and caudal metacarpal surfaces. The tendons on the dorsal digital aspect and the first phalanx of the fourth digit along with tendons on the caudal metatarsal aspect of the paw were exposed (Figure 2A). Partial loss of the exposed tendons was also evident. Median duration of clinical signs for the eight animals was 11.5 mo (mean, 13.92 mo; range, 6 days to 36 mo).
Citation: Journal of the American Animal Hospital Association 47, 6; 10.5326/JAAHA-MS-5609
Citation: Journal of the American Animal Hospital Association 47, 6; 10.5326/JAAHA-MS-5609
Clinical Pathology, Cytology, Dermatologic Tests, and Microbiology
A complete blood count and serum biochemistry profile was performed on all animals included in this study. In all animals, the complete blood counts and biochemistry profiles were within normal limits. Tests for dogs with pododermatitis included skin scrapes, skin swabs for cytology (case 2), allergy tests (case 5), and culture and sensitivity testing of the excised tissue after the podoplasty procedure. Cytology of skin swabs taken from the pads of case 2 revealed the presence of rods, cocci, and yeast. The allergy tests of case 5 showed that the dog was sensitive to fleas and wool. Aerobic cultures revealed the presence of Staphylococcus intermedius (cases 1 and 5), Corynebacterium spp. (case 5), and Enterococcus spp. (case 2). The culture from case 6 showed a mixed population of Staphylococcus spp. and Streptococcus spp., and cultures from the interdigital tissues of case 8 isolated Streptococcus canis group C.
Radiographic Examination
Radiographic examination of the affected limbs was performed for cases 3 and 7. In case 3, radiographic examination of the left forelimb revealed the presence of a deformed manus with malformation and derangement of the carpal bones. The distal limb had a split appearance between the second and third metacarpal bones, and severe angulation of the distal phalanx of the second digit was also visualized. In case 7, radiographic examination of the right hind limb showed: chronic hyperextension of the metatarsophalangeal joints with remodeling and malformation of the digits with metarsophalangeal and interphalangeal ankylosis of the second and third distal digits. The metatarsal bones of the right limb were approximately 3 cm shorter than on the left with medial bowing of the distal diaphysis of the fifth metatarsal of the right limb.
Surgical Procedures
Six dogs had TFPs and two animals had PFPs. Two dogs had bilateral TFPs: case 5 had the podoplasties staged in a 6 mo period; and case 6 had bilateral forepaw podoplasties in the same anesthetic incident. TFPs were performed after a tourniquet was placed around the distal limb then all of the inderdigital skin was excised. The dissection was performed starting on the dorsum of the paw, proceeding in a proximal to distal direction. Only 2–3 mm of skin adjacent to the nails was preserved. Following removal of the interdigital webs, the dissection was continued toward the palmar/plantar surface of the paw by removing the skin between the digital and metacarpal/metatarsal pads. Care was taken to preserve the digital nerves and vessels during dissection. The tourniquet was released and hemorrhage was controlled with electrocoagulation and pressure. The digital pads were apposed by placing simple interrupted 3-0 nylona or polypropyleneb skin sutures between each pad. The metacarpal/metatarsal pad was apposed to the digital pads using the same suture pattern. Simple interrupted skin sutures were placed to appose digital skin edges dorsally. In case 5, a one-quarter inch Penrose drainc was inserted in a transverse fashion across the paw and along the cranial edge of the metacarpal/metatarsal pad before the last pad sutures were placed. In case 3, in addition to the podoplasty, an extra nail was also removed. In case 7, amputation of the distal fifth metatarsal bone and associated digit of the right hind paw was performed through a curvilinear incision along the bone. The distal aspect of the second and third digits was also removed, taking care to preserve most of the digital pads. The remaining interdigital skin was excised, and fusion of the digits and digital pads was achieved by placing simple interrupted 3-0 nylon sutures in the skin of the dorsal and ventral paw (Figure 3). No drain was placed in the podoplasty wound. The subcutaneous tissue and skin in the lateral incision (through which the metatarsal bone and fifth digit were removed) were closed with 3-0 polydioxanoned and 3-0 nylon sutures, respectively. In case 8, podoplasty was part of the reconstruction performed on the left hind paw. Following aggressive debridement of most of the interdigital and interpad tissues, leaving an almost webless left hind paw (Figure 2B), and after vacuum-assisted closure (VAC)e was applied to the wound, a TFP was performed by apposing only the pads on the plantar aspect of the paw, leaving the dorsal part of the digits as an open wound.
Citation: Journal of the American Animal Hospital Association 47, 6; 10.5326/JAAHA-MS-5609
For the PFPs (cases 2 and 4) all of the skin of the interdigital web between the third and fourth digits was removed from both the dorsal and ventral paw, after a tourniquet was placed around the distal limb, to ensure complete interdigital and interpad skin removal. The digital nerves and vessels were preserved during dissection, and hemorrhage was controlled using electrocoagulation. The tourniquet was removed, and the interosseous muscles and subcutaneous tissues of the adjacent digits, from both the dorsal and ventral paw, were apposed with a 3-0 and/or 4-0 monofilament absorbable suture material. The dorsal and the palmar/plantar skin edges of the adjacent digits were united with 3-0 polypropylene or nylon. In case 4, the digital pads of the third and fourth digits were apposed with the metacarpal pad, which was devoid of skin. A gap measuring approximately 0.5 cm on the dorsal aspect of the paw, in between the digits, was left open to facilitate drainage. Median duration of the surgical procedure was 120 min (mean, 136.25 min; range, 60–370 min).
Histopathology
Lesions characterized by chronic, severe and multifocal pyogranulomatous pododermatitis and furunculosis with dermal fibrosis and moderate to marked follicular edema were detected (cases 1, 2, and 5). For cases 3, 4, 7, and 8, no histopathology was performed. Intralesional and intrafollicular gram-positive cocci were also evident in cases 1 and 5. Histopathologic evaluation of samples obtained from the interdigital skin of case 6 was compatible with a chronic wound.
Postoperative Care
All animals were fitted with an Elizabethan collar and were administered analgesics. Antibiotics prescribed included: cephalexinf (cases 1, 2, 3, 5, and 6), cephalexin and enrofloxacing (case 7), and amoxicillin trihydrate/clavulanate potassiumh (cases 4 and 8). Choice of antibiotic was either based on culture and sensitivity or administered empirically. The drains in case 5 were removed 10 days after surgery. A bandage was subsequently placed on the paws, and a “clam-shell” non-weight-bearing bandage splint was applied. Dogs with pododermatitis had daily bandage changes initially, followed by bandage changes q 48 hr, depending on the amount of drainage. Median duration of bandaging was 14 days (mean, 30.85 days; range, 10–120 days), and median duration of hospitalization was 5.28 days (mean, 2.33 days; range, 2–16 days).
Complications and Outcome
Slight dehiscence of the wound between the pads was noted in four dogs in the short term. These were treated with open wound management with bandaging. Most separations were noted between the metacarpal/metatarsal pads and digital pads (cases 3, 5, 6, and 8) or among the digital pads (case 2). Mean time that dehiscence was noted for five podoplasties was 11 days after surgery (range, 8–12 days after surgery). In case 8, following TFP, the wound was bandaged and VAC was applied again for 3 more days. Debridement was also performed on the day of VAC application. On day 10 after podoplasty, two open wounds were evident in the dorsal digital aspect and the caudal aspect of the paw dorsal to the metatarsal pad, exposing digital flexor tendons, respectively. At that time, healthy granulation tissue was forming, and the wound was left to heal by second intention. The first phalanx of the fourth digit and a portion of the digital pad were excised because they developed signs of necrosis. A slight separation between the metatarsal pad and digital pads was evident on day 12 after surgery, and the wound was left to heal by second intention along with the other wounds of the paw. The podoplasty wounds healed well in all cases (Figure 2C).
Following bandage removal, six animals had normal ambulation and two dogs (cases 7 and 8) had slight weight-bearing lameness exacerbated by exercise. The lameness persisted throughout the study in case 8, but was intermittent in the other dog (case 7). Case 7 showed significant progress in terms of limb function compared to the presurgical limb function. Median follow-up time was 29 mo (mean, 37.37 mo; range, 7–96 mo). Complete resolution of abnormalities needing podoplasty was reported in six animals.
Discussion
Chronic interdigital furunculosis (pyoderma) was the most common indication for performing podoplasty in this and other studies.2 Breeds represented and lesion location noted in the present study were in agreement of those reported elsewhere.2,8–10 The purpose of TFP performed in cases 1 and 5 was to remove all of the inflamed tissue and to reconstruct the paws to increase stability and restore the weight-bearing surface of the paws.
One dog with localized furunculosis in the interdigital web between the third and fourth digits of the right forepaw had the diseased web removed. A PFP was subsequently performed to reconstruct the paw. In contrast, other reports describe the use of separation podoplasty, entailing creation of individual digits by suturing the dorsal skin to the palmar skin of each digit.11 The formation of individual digits may lead to closer than normal apposition of the adjacent digits and a webless space, which may result in loss of paw support, mild lameness, and may make digits subject to snagging on vegetation (especially working field dogs).1,12 In the current study, PFP was performed to eliminate these problems and provide stability to the paw.
An English bulldog in this study underwent TFP of both forepaws for the treatment of redundant skin protruding through the interdigital space of the paws. This condition had started when the dog was a puppy, and had resulted in chronic traumatization of the skin folds. The condition described here might resemble cutis laxa or elastolysis, a hereditary disorder of progressive loss of elastic fibers in humans, resulting in pendulous, excessive, and flaccid skin folds with no fragility present.13 To the authors’ knowledge, the present disease has not been documented in dogs; however, because no special stains were performed during histopathology, no definitive diagnosis could be made. The excessive skin was excised from all interdigital webs, and reconstruction was provided by TFP.
The cat included in this study underwent TFP for the management of a chronic postural deformity because of overextension of the third and fourth digits of the left forepaw after undergoing tendonectomy to minimize destructive scratching.14 Deep digital flexor tendonectomy may be used as an alternative to onychectomy in cats.15 Complications associated with tendonectomy include hemorrhage, infection, persistent lameness, interphalangeal joint stiffness, fibrosis, pain, claw ingrowth into digital pads, and behavioral changes.6,15,16 Postural defects after digital deep flexor tendon severance are considered to be an indication for surgical exploration and repair with minimal delay.3,17 Chronic injuries of the deep flexor tendons may be difficult to treat because poor tendon vascularity, the small size of the animal, and fibrosis of the ends of the tendonds may make tendon identification, anastomosis, and healing extremely problematic.3,17,18 A TFP was described in a dog for the management of disruption of all flexor tendons of the right forelimb.3 In view of a poor prognosis, a modified PFP of the third and fourth digits, accompanied by apposition of the digital pads with the metacarpal pad, was performed. The rationale behind performing a PFP rather than a TFP was the management of overextension of only the weight-bearing digits that were affected by returning the pads and digits to a normal position to provide a stable and functional paw.
Case 3 was diagnosed with ectrodactyly of the left forepaw. This is a congenital digital separation extending between the metacarpal bones. In a previous report, PFP was used for the treatment of a forelimb ectrodactyly in a West Highland white terrier. Three months after surgery, the dog was reported to have a varus deformity of the carpus with mild lameness after vigorous exercise.4 In contrast to the previous report, TFP was implemented to successfully treat the dog described in the current study. The aims were to increase the stability of the carpus and provide a larger weight-bearing surface by fusing all of the digital and metacarpal pads together. Seventy months after surgery, no lameness was reported for this case.
Case 7 was diagnosed with a conformational deformity of the right hind paw. The medially bowed fifth metatarsal and associated digit along with the distal malformed phalanges of the second and third digits were amputated to correct the deformity. This was followed by a TFP to provide a more functional weight-bearing surface of the right hind paw. Twenty-four months after surgery, the dog was reported to be significantly better than it was before surgery, having only a mild, intermittent, permanent weight-bearing lameness during exercise. The lameness in this case may be attributed to some residual conformational deformity requiring further corrective surgery and/or to the digit amputation that this dog previously underwent.5
Necrotizing fasciitis is considered to be a rapidly progressive, life-threatening, and invasive bacterial infection of the fascial planes and subcutaneous tissue in dogs. It is mainly associated with Streptococcus canis infection, and is commonly localized in the limbs.19,20 Case 8 was recognized with necrotizing fasciitis in the left hind paw, and its clinical signs were consistent with the above findings. TFP may also be considered as a salvage procedure to reconstruct degloving injuries of the digits in cats.21 In the current study, the rationale behind the performance of TFP of the plantar aspect of the paw was to minimize dead space, to accelerate wound healing, to increase the weight-bearing area, and provide stability of the paw. The shortage of available skin on the dorsal aspect of the digits, together with the exposure of a phalanx, precluded any suturing in this area, leaving the dorsal digital paw as an open wound. If the webless paw was left without reconstruction, loss of support for the paw and a more significant lameness would be evident.12 The slight lameness in case 8 may be due to the partial loss of tendons because of the necrotizing fasciitis.
Dehiscence or separation between the fused pads was the most common complication in the present and other studies.2,3 This complication occurred despite the application of a “clam-shell” bandage in all of the affected dogs between days 8 and 15 after surgery. It was reported that dogs with longer paws had an increased tendency for separation between the metacarpal/metatarsal and digital pads.2 This was not supported by the findings in the present study in which only one of the five dogs (case 8) that showed separation had longer paws. Six of the eight animals were ambulatory by the time of bandage discontinuation, showing normal limb function. This finding compares favorably with other reports.2,3
Conclusion
TFP or PFP was performed as a salvage procedure in seven dogs and one cat for the treatment of inflammatory, traumatic, congenital, and orthopedic conditions of the paws. Fusion podoplasty is regarded as a major surgery, requiring considerable time for the surgical procedure to be carried out. Postoperative care of these patients may be laborious and long-term bandaging of the affected paws is needed. Four dogs showed dehiscence among the digital and metacarpal/metatarsal pads, all of which were allowed to heal secondarily. Fusion podoplasty allowed for a normal ambulation in six animals, whereas two dogs had mild, long-term lameness after a median follow-up time of 29 mo. Complete resolution of clinical signs was reported in six animals, and no recurrence of the underlying disease was noted. Fusion podoplasty may be an effective means of treating various pedal conditions such as those described in the current study.
Photograph of the palmar surface of both forepaws of case 6. Both paws were affected by redundant interdigital skin folds. An ulcer was also noticed on one of the forepaws.
A: Photograph of the plantar surface of the left hind paw in case 8, which was diagnosed with necrotizing fasciitis. Ulceration and necrosis of the paw, along with exposed tendons of the caudal metacarpal surface, were evident. B: Photograph of the plantar surface of the paw in the same dog following aggressive debridement. An almost webless paw was left. Exposed tendons were also evident in the caudal metatarsal surface. C: Photograph of the dorsal surface of the paw in the same dog 7 mo after surgery.
Photograph of the palmar surface of the left forepaw of case 3 following completion of the fusion podoplasty.
Contributor Notes
A. Coomer's present affiliation is Veterinary Surgical Centers Berkeley, Berkeley, CA.
