Analysis of outcome in dogs that undergo secondary amputation as an end-point for managing complications related to limb salvage surgery for treatment of appendicular osteosarcoma.

Appendicular osteosarcoma (OSA) remains a prevalent musculoskeletal cancer in dogs and definitive local control followed by adjuvant cytotoxic chemotherapy is considered the gold standard approach. Several studies support surgical limb salvage as a means of local control with similar outcomes compared with limb amputation. Complications are well described for limb salvage but little is known of dogs that undergo secondary amputation as a result of complications and outcomes specific to this group. A retrospective analysis of dogs in an institutional primary bone tumour registry was performed to identify dogs diagnosed with histologically confirmed OSA treated with surgical limb salvage with a technique that required an implant to reconstruct the osseous defect. A total of 192 dogs were identified with 31 dogs undergoing secondary amputation representing a limb preservation rate of 84%. A total of 111 dogs were analysed: 31 secondary amputation cases and 80 controls were selected for comparison. The most common reasons for secondary amputation were local recurrence (LR) and surgical site infection (SSI), with odds ratios of 3.6 and 1.7, respectively. Dogs that underwent secondary amputation had a significantly (P = .05) longer median disease specific survival time (ST) (604 days) compared with the control group (385 days). Dogs lived for a median of 205 days beyond secondary amputation and 97% had good functional outcome. Significant independent factors that positively influenced ST were secondary amputation, moderate SSI, severe SSI and age.

Limb-sparing in dogs using patient-specific, three-dimensional-printed endoprosthesis for distal radial osteosarcoma: A pilot study.

Limb-sparing for distal radial osteosarcoma has a high rate of complications. Using personalized three-dimensional (3D)-printed implants might improve outcome. The goals of this study were to optimize use of patient-specific, 3D-printed endoprostheses for limb-sparing in dogs in the clinical environment and to report the outcome. This was a pilot study where five client-owned dogs were enrolled. Computed tomography (CT) of the thoracic limbs was performed, which was used to create patient-specific endoprostheses and cutting guides, and repeated on the day of surgery. Intra-arterial (IA) carboplatin was introduced in the clinical management. Limb-sparing was performed. Outcome measures were time required to produce the endoprosthesis and cutting guide, fit between cutting guide and endoprosthesis with host bones, gait analysis, size of the tumour, percent tumour necrosis, complications, disease-free interval (DFI) and survival time (ST). Four dogs received IA carboplatin. Excessive tumour growth between planning CT and surgery did not occur in any dog. The interval between the CT and surgery ranged from 14 to 70 days. Fit between the cutting-guide and endoprosthesis with the host bones was good to excellent. At least one complication occurred in all dogs. Two dogs were euthanized with STs of 192 and 531 days. The other dogs were alive with a follow up of 534 to 575 days. IA chemotherapy is a promising strategy to minimize the risk of excessive tumour growth while waiting for the endoprosthesis and cutting-guide to be made. The design of the cutting-guide was critical for best fit of the endoprosthesis with host bones.

Pathologic fracture healing after femoral limb salvage in a dog.

BACKGROUND: Bone sarcomas are a significant cause of pain, disability, and mortality in dogs. A variety of surgical limb salvage options are available to preserve limb function with comparable prognosis to amputation. CASE REPORT: This report describes successful healing after plate fixation of an undifferentiated sarcoma pathologic femoral fracture in a dog. The fracture was treated surgically with curettage of the tumour site, placement of autogenous bone graft, and then stabilized using a locking plate rod construct. The patient regained excellent mobility after surgery and was managed with monthly pamidronate therapy. Serial radiographs demonstrate progressive healing of the pathologic fracture. Ultimately, the patient developed a maxillary fibrosarcoma and was euthanased 1 year after treatment of the femoral fracture. Postmortem histopathological evaluation of the pathologic fracture site demonstrated complete bone healing. CONCLUSION: This case highlights the possibilities of limb salvage by fracture stabilization and bone healing as a viable option in select patients.

Limb-shortening limb salvage (LSLS) in a cat with metatarsal osteosarcoma.

The objective of this report was to document a successful partial limb amputation surgery in a cat with metatarsal osteosarcoma (OSA) including the use of pad grafts from the amputated foot. Limb shortening of the hindlimb through a partial amputation resulted in excellent limb function and usage. The patient retained functional use of the limb after surgery, with no lameness. There was no evidence of metastasis or local recurrence seen 323 days post-surgery. Limb shortening partial amputation is a reasonable option and can result in excellent limb use after surgery despite a significant loss in limb length.

Intervention pour raccourcir et sauver un membre chez un chat atteint d'un ostéosarcome métatarsien. L'objectif du présent rapport consistait à documenter une chirurgie d'amputation partielle réussie chez un chat atteint d'un ostéosarcome métatarsien y compris l'usage de greffes des coussinets du pied amputé. Le raccourcissement du membre postérieur par une amputation partielle a donné d'excellents résultats pour la fonction et l'usage du membre. Le patient a conservé l'usage fonctionnel du membre après la chirurgie, sans boiterie. Il n'y avait aucun signe de métastase ni de récurrence locale lors d'un examen 323 jours après la chirurgie. L'amputation partielle et le raccourcissement du membre sont une option raisonnable et peuvent produire une excellente utilisation du membre après la chirurgie malgré une perte importante de la longueur du membre.(Traduit par Isabelle Vallières).

Lateral manus translation for limb-sparing surgery in 18 dogs with distal radial osteosarcoma in dogs.

OBJECTIVE: To describe and report outcomes after lateral translation of the manus for limb-sparing management of distal radial osteosarcoma in dogs. STUDY DESIGN: Retrospective case series. STUDY POPULATION: Eighteen client-owned dogs. METHODS: The distal aspect of the affected radius and associated neoplastic tissues were excised. The distal aspect of the ulna was preserved except for its medial cortex, which was removed en bloc with the radial segment. The manus was translated laterally to place the radial carpal bone in contact with the distal aspect of the ulna. A limb-sparing or locking compression plate was placed on the remaining proximal radius and the 3rd metacarpal bone. A 3.5-mm SOP (string of pearls) plate was placed on the lateral aspect of the proximal ulna and the 4th metacarpal bone. Dogs were administered chemotherapy. Data were collected to assess surgical and oncologic outcomes. Limb function was subjectively assessed. RESULTS: The percentage of radius removed ranged from 43% to 94% (median 54%). Complications developed in 12 limbs, with infection in 10, biomechanical complications in 6, and local recurrence in 4. Limb function was subjectively assessed as acceptable. Median disease-free interval was 219 days, and median survival time was 370 days. CONCLUSION: Outcomes after lateral translation of the manus compared favorably to other limb-sparing techniques for dogs with distal radial osteosarcoma, particularly in dogs requiring excision of a large segment of the radius. CLINICAL SIGNIFICANCE: The lateral manus translation provides an alternative limb-sparing technique that does not require an allograft, endoprosthesis, or autograft.

Hemipelvic and proximal femoral limb salvage endoprosthesis with tendon ongrowth in a dog.

OBJECTIVE: To report the clinical application of a hemipelvic and proximal femoral endoprosthesis for limb salvage. STUDY DESIGN: Retrospective case report. ANIMAL: One 5-year-old, neutered female, flat coated retriever with a malignant neoplasia of the left coxofemoral joint. METHODS: An invasive soft tissue mass (histiocytic sarcoma) with bone lysis of the femoral head and acetabulum was noted on radiographs, computed tomography (CT), and MRI. Custom-designed hemipelvic and proximal femoral endoprostheses were produced from CT images and manufactured with hydroxyapatite coated surfaces to allow tissue integration. The proximal femoral implant allowed tendon ongrowth and muscle attachment. The pelvic implant was anchored to the ilium and ischium with screws, and the femoral implant was cemented. Chemotherapy consisted of lomustine (CCNU). RESULTS: No evidence of implant loosening or local/thoracic metastases was noted on radiographs or CT at 6 weeks and at 3, 6, 9, and 12 months after surgery. A neurapraxia resolved 14 weeks postoperatively. Intensive rehabilitation was performed. At 12 months, activity was unrestricted with minimal residual lameness. The dog was euthanized at 14 months for metastatic disease. CONCLUSION: Limb salvage with a hemipelvic and proximal femoral endoprosthesis resulted in limb function and survival for 14 months. CLINICAL SIGNIFICANCE: Neoplasia involving the bones of the coxofemoral joint traditionally requires hemipelvic resection and pelvic limb amputation. This report provides evidence that limb salvage can result in satisfactory levels of activity.

Modification of the metal endoprosthesis limb-salvage procedure for excision of a large distal radial osteosarcoma in a dog: A case report.

OBJECTIVE: To report modification of the endoprosthesis surgical limb-salvage technique to treat a locally extensive osteosarcoma in a dog and associated functional outcome. STUDY DESIGN: Clinical case report. ANIMALS: One client-owned dog. METHODS: A 9-year-old dog was presented for treatment of a locally extensive distal radial osteosarcoma. A limb-salvage surgery was performed with a second-generation Veterinary Orthopedic Implants (VOI) endoprosthesis to reconstruct the radial segmental and carpal osseous defect. The endoprosthesis was stabilized with a 16-mm-wide locking VOI limb-salvage plate. The level of the osteotomy of the radius/ulna was 3 cm proximal to the periosteal reaction seen on radiographs, and the distal osteotomy extended through the proximal metacarpal bones (II-V), 3 cm from the distal extent of the soft tissue component of the tumor. A 3.5-mm SOP (String of Pearls) plate was used as adjunct fixation. RESULTS: The postoperative functional outcome was classified as acceptable. Ambulation was normal, with mild subjective lameness on the treated limb at examinations 20, 43, and 63 days after surgery. The dog was euthanized 92 days after surgery because of progressive metastatic disease. CONCLUSION: The modified endoprosthetic technique allowed complete excision of the carpal joint, which resulted in acceptable functional outcomes in the dog described here. CLINICAL SIGNIFICANCE: Distal ostectomies may include part of the manus during limb salvage surgery of locally extensive distal radial osteosarcoma and using an endoprosthesis implant to reconstruct the defect.

Limb shortening as a strategy for limb sparing treatment of appendicular osteosarcoma of the distal radius in a dog.

OBJECTIVE: To develop and report a novel limb sparing technique for the distal radius in a dog. STUDY DESIGN: Case report. ANIMAL: A 14-year-old, female spayed Labrador Retriever with an osteosarcoma of the right distal radius and a pathological fracture. A previous mast cell tumor had been treated 5 years prior to presentation with marginal excision and a full-course radiation over the right metacarpal bones. The dog had received 2 doses of palliative radiation just prior to presentation. METHODS: A standard resection of the distal radius was used as a strategy to salvage the limb. Instead of replacing the 6-cm bone defect with an endoprosthesis, the limb was acutely shortened and a carpal arthrodesis plate was applied. RESULTS: Postoperative function was good and limb shortening was well-tolerated. Radiographic evidence of early bone healing was noted at the osteotomy site. The dog experienced 3 postoperative complications: a focal area of skin necrosis managed successfully via surgical revision; infection resolving after long-term antibiotherapy; and a fracture of the third metacarpal bone through a screw hole, managed via screw removal and a custom external prosthesis. The patient was euthanatized due to presumptive chemotherapy complications 127 days after the procedure. CONCLUSION: Limb shortening limb salvage is technically feasible and can result in excellent limb use postoperatively, in spite of a significant loss in limb length.

Compartmental resection of peripheral nerve tumours with limb preservation in 16 dogs (1995-2011).

Peripheral nerve tumours (PNTs) affecting the limbs may lead to chronic pain, lameness and/or monoparesis that is refractory to medical treatment. The most common radical therapy for PNTs has been surgical excision with limb amputation. However, compartmental resection with preservation of the limb has been performed by the authors with favourable clinical results and therefore this bi-institutional retrospective study was undertaken to assess limb function, survival and recurrence. Sixteen dogs that had been diagnosed with PNTs between 1995 and 2011 met the inclusion criteria for this study. In the majority of the cases, good to excellent limb function was achieved. The overall median survival time (MST) was 1303days (42.8 months; range, 14 days-4639 days, [0.5-152.4 months]), with two dogs still alive at time of evaluation. Non-infiltrated margins were the best prognostic indicator; dogs with non-infiltrated margins had a MST of 2227days (P<0.001) compared to dogs with infiltrated margins (MST of 487 days). The 1-year calculated survival rate was 68.8% and the 2- and 3-year calculated survival rates were 62.5%. Surgical treatment with tumour removal and limb spare for proximal and distal PNTs can be successful. Compartmental excision can lead to good limb function, producing survival comparable to limb amputation, and should therefore be considered as an alternative to limb amputation in canine PNTs.

Orthogonal bone plate stabilization for limb-sparing surgery.

This report describes limb-sparing surgery in a 35 kg, six-year-old Hungarian Vizsla with a distal radial lytic bone lesion. Preoperative biopsy had suggested a bone cyst, however histopathology on the excised bone segment was indicative of an osteosarcoma. Following excision of the tumour, the bone defect was filled with a composite bone graft and stabilized with a custom-made dorsal 3.5/2.7 mm pancarpal arthrodesis plate and an orthogonally positioned medial 2.7 mm compression plate. This technique has not previously been described for limb-sparing procedures. No complications were encountered, and despite the owners declining adjunctive chemotherapy, the dog was alive 34 months postoperatively with near normal limb function.

Endoprosthesis (EN) in frontlimb-sparing surgery for distal radial tumours in the dog: preliminary results.

In veterinary medicine, limb-sparing techniques are most implemented when the uninvolved limbs are affected by other orthopaedic or neurological disorders, in large breeds or when the owner declines amputation. This report describes the surgical technique used for implantation of an endoprosthesis following tumour resection in the distal radius in 3 dogs using both standard and angle-stable plates. Endoprosthesis offers an easy and readily available surgical alternative to cortical allografts. Despite post-operative complications, this technique resulted in a good quality of life in all 3 dogs.

Loss of implant-bone interface following distal radial locking-plate endoprosthesis limb-sparing surgery in a dog.

An eight-year-old, neutered female Rottweiler was presented with lameness of seven days duration. Radiographs were consistent with a distal radial bone tumour. Limb-sparing surgery was performed using a commercially available endoprosthesis with a locking bone plate. Histopathological examination of the resected bone revealed an intraosseous fibrosarcoma, and postoperative adjuvant chemotherapy was initiated three weeks after surgery. Despite initial satisfactory limb function, lameness worsened four months after surgery. Radiographs revealed large areas of bone lysis around the proximal and distal screws, leading to significant resorption of the radius and radial carpal bone with subsequent construct failure. Further treatment was declined by the owner and the dog was subsequently euthanased. This case illustrates that implant failure is not necessarily averted by the use of locking (compared with non-locking) implants combined with an endoprosthesis to treat distal radial tumours in dogs.

Transtumoral plating as a novel method for palliative limb spare and thromboembolism in a dog with a distal radial primary bone tumor.

A 7-year-old, spayed, female great Pyrenees with a primary tumor of the distal radius was treated with placement of a bone plate that spanned the tumor. The goals were palliation and prevention of pathologic fracture. This is an option for select patients with osteosarcoma.

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.

Intraosseous transcutaneous amputation prosthesis (ITAP) for limb salvage in 4 dogs.

OBJECTIVE: To report clinical application of intraosseous transcutaneous amputation prosthesis (ITAP) for limb salvage. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Client owned dogs with malignant neoplasia of the distal aspect of the limb. METHOD: Distal limb amputation allowed press-fit insertion of the ITAP into the radius (n = 3) or tibia (1). Remaining soft tissues including skin were attached directly to the ITAP. Limb stump and ITAP were protected by bandaging (1) or external skeletal fixation (3) for 5-6 weeks before exoprosthesis attachment. Measures of outcome included subjective assessments of limb function by owners and veterinarians, radiographic (4) and histologic (1) examination. RESULTS: Dermal integration with the ITAP was achieved by 3 weeks and dogs were walking in a pain-free manner by 8 weeks. One dog was administered adjunctive carboplatin chemotherapy. No evidence of local tumor recurrence occurred. In 1 dog, ITAP fracture occurred at 10 weeks and was successfully managed by ITAP replacement. Three dogs were euthanatized because of confirmed or assumed metastatic disease at 8, 12, and 17 months. Histologic examination of the ITAP-limb interface at 1 year documented osseous and dermal integration. CONCLUSION: Implantation of ITAP to the distal limb of dogs is feasible and can result in favorable functional outcomes. Biological integration of osseous and dermal tissues with ITAP is reliable and robust.

Intraoperative radiation for limb sparing of the distal aspect of the radius without transcarpal plating in five dogs.

OBJECTIVES: To evaluate intraoperative irradiation (IORT) as a method of limb spare with preservation of the radiocarpal joint. STUDY DESIGN: Prospective case series. ANIMALS: Dogs (n=5) with stage II sarcoma of the distal aspect of the radius. METHODS: A bone segment containing the tumor was isolated surgically, treated by IORT, reimplanted, and secured by internal fixation. In 1 dog, the postradiation tumor bed was curetted and filled with bone cement. Dogs were administered alternating adriamycin and carboplatin starting 2 weeks after IORT and monitored at regular intervals. RESULTS: Four dogs had osteosarcoma and 1 had undifferentiated sarcoma. Implant failure (n=3), deep tissue infection (3), and pathologic fracture (3) resulted in amputation (3) or pancarpal plating (2). The dog with undifferentiated sarcoma was euthanatized because of suspected tumor recurrence 4 months postoperatively. Osteotomy healing was documented by radiography (1), histopathology (2), or by direct observation (2). CONCLUSIONS: A technique for limb-sparing surgery of the distal portion of the radius in dogs using IORT had advantages include healing of the autograft and a source for a perfectly fitting autograft but did not appear to offer any advantage with respect to infection rate. Long-term preservation of the radiocarpal joint was not successful. CLINICAL RELEVANCE: It was not possible to preserve the function of the radiocarpal joint and so this technique cannot be recommended currently. Further study is needed to evaluate whether or not IORT can be considered in combination with pancarpal plating and possibly curettage and cementation of the tumor to prevent subchondral bone collapse.

Transverse ulnar bone transport osteogenesis: a new technique for limb salvage for the treatment of distal radial osteosarcoma in dogs.

OBJECTIVE: To develop instrumentation and a technique for transverse ulnar bone transport osteogenesis in dogs. STUDY DESIGN: Cadaveric study and in vivo validation (1 dog). SAMPLE POPULATION: Paired cadaveric antebrachii (n=10 dogs) and 1 live dog. METHODS: Circular fixator constructs were applied and fitted with reeling or linear motors designed to transport an ulnar segment transversely into a defect created by excising the distal 50% of the ipsilateral radius. A longitudinal osteotomy of the adjacent ulna was created and the segment was transported across the radial defect. Pre- and post-distraction CT scans were used to compare the efficacy of each construct. The procedure was performed unilaterally in a live dog using the reeling motor (RM) construct. RESULTS: Both constructs effectively transported the ulnar segment into the defect. Subjectively, the RMs were easier to apply and operate. No significant differences were observed in the objective measures of efficacy between the 2 construct types. The live dog produced viable regenerate bone after transverse ulnar bone transport. CONCLUSIONS: Transverse ulnar bone transport should be considered a potential method for limb salvage in dogs with osteosarcoma (OSA) of the distal radius. The RMs were effective and clinically applicable. CLINICAL RELEVANCE: Transverse ulnar bone transport osteogenesis affords the benefits of longitudinal radial bone transport osteogenesis, allowing resolution of large longitudinal radial defects in a substantially less time as a result of shortening the transport distance. This would be beneficial when treating conditions such as OSA where minimizing convalescence and maximizing quality of life is a priority.

Septic arthritis of the distal interphalangeal joint in cattle: comparison of digital amputation and joint resection by solar approach.

OBJECTIVE: To determine in cattle with septic arthritis of the distal interphalangeal joint (SADIJ) the efficacy of resection of the distal interphalangeal joint (JRES) as a digit salvage technique compared with digital amputation (DAMP). STUDY DESIGN: Prospective, randomized clinical study. ANIMALS: German Holstein-Friesian dairy cattle with SADIJ of 1 hind limb (n=52). METHODS: SADIJ diagnosis was based on clinical examination and radiography. Cows were randomly assigned with owner consent to DAMP (n=26) or JRES (n=26). After JRES, a wooden block was fixed to the partner claw in combination with a tipping claw prophylaxis. RESULTS: After surgery, degree of lameness improved significantly faster after DAMP than after JRES. New claw diseases in the opposite limb occurred more frequently after JRES (n=6) than after DAMP (n=1). New claw defects developed in the partner claw on the operated limb in 6 cows after DAMP compared with 1 after JRES. Tipping claw was observed in 50% of JRES cows at day 180. Mean life span between groups was not significantly different (DAMP=13.5 months, JRES=10.9 months). CONCLUSION: Higher surgical and postsurgical expenditures for JRES were not counterbalanced by a longer productive life; however, frequent disease of the partner claw of cows after DAMP should be considered a critical point, as this generally leads to culling. CLINICAL RELEVANCE: The higher expenditure for JRES can be justified only for young, valuable cattle.

Longitudinal bone transport for treatment of primary bone tumors in dogs: technique description and outcome in 9 dogs.

OBJECTIVE: To describe a surgical technique for bone transport osteogenesis (BTO) limb salvage and report outcome in 9 dogs with primary bone tumors. ANIMALS: Nine dogs with spontaneously occurring primary bone tumors. RESULTS: BTO surgery was performed as a primary means of limb salvage in 7 dogs and as a salvage procedure after catastrophic allograft infection and failure in 2 dogs. Mean defect size was 9.5 cm with a mean of 123 days distraction until docking. Mean time from surgery to fixator removal was 205 days. Minimum follow-up was 9 months. There were 2 histologically confirmed local recurrences where although limb function was excellent, eventually resulted in limb amputation. Limb function was good to excellent in all but 2 dogs; 1 was chronically non-weight bearing before BTO surgery because of complications associated with an allograft limb salvage that had been performed previously on the same limb. The cause of lameness in the other dog was undetermined. CONCLUSIONS: BTO limb salvage can be successful in dogs with primary bone tumors. Whereas allograft limb salvage may be simpler from an initial management perspective, BTO has some unique advantages when compared with the allograft technique. CLINICAL RELEVANCE: BTO has an emerging role in limb salvage surgery for dogs with primary bone tumors. BTO provides excellent long-term outcomes in some dogs with primary bone tumors and will likely become increasingly more attractive as technique modifications allow the duration of the treatment to be shortened.