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CHD手術治療和TPO骨板要不要拆除的觀感

寫此文章的目的在於讓飼主了解當選擇手術治療時為何我建議選擇TPO手術優先於人工關節置換？TPO手術復原後為何建議拆除骨板？這些是基於相關研究文獻和醫生的職業道德考量，最後決定權還是在飼主。

TPO手術是切開三處骨盆骨(腸骨、恥骨、坐骨)翻轉關節窩，使關節窩覆蓋股骨頭的面積增加，同時改進鬆弛度的問題，整個手術過程髋關節沒有被打開和手術的傷害，保留原來的關節結構，手術恢復後可以過正常狗的生活方式。

TPO手術復原後，如果不幸發生意外例如車禍產生關節附近或股骨的骨折，醫生可以用正常狗車禍模式修復即可，但是人工關節置換後，該處發生骨折幾乎很難修復，大部分需要把人工關節取下才能整復，人工關節的手術費用是TPO的好幾倍，以經濟和對狗來說TPO應該是手術治療CHD的優先選擇，但是TPO手術有時間和嚴重程度的限制，最好的手術時間是6到11個月齡，髋關節需要沒有退化性關節炎的產生或輕微的退化性關節炎發生及股骨頭未完全脫離關節窩之前就需要完成，所以這個手術一但決定就需要把握時間，以爭取最好的手術效果。

每個手術皆可能產生併發症，以TPO和人工關節比較，皆有金屬植入物在體內，骨板等金屬植入物在體內，文獻報導可能產生骨癌，人工關節植入物也不例外，雖然產生的機會很低，一但發生就來不及，所以可以拆除的骨板為何還留在體內？人工關節是代替關節結構的植入物，不可能拆除，除非感染或鬆脫，以這個觀點來說，TPO又比人工關節多一個優點，恢復後可以拆除不須留在體內，飼主有權了解各種可能併發症來決定拆與不拆，確實有些美國醫生建議不拆，但也有很多美國醫生建議拆除，我的建議是拆除比較好，因為TPO手術的狗還年輕，除了骨癌，骨板下的骨頭比較疏鬆脆弱及因氣候變化所產生的痠痛不舒服感覺等併發症，也是拆除的考慮因素，我們在臨床上遇過TPO手術後一年多沒拆骨板，手術部位皮膚被狗舔到潰爛，取出古版後才恢復正常的病歷，以人醫的立場來說也建議拆除，飼主可以詢問人醫骨科醫生來證實。

有些飼主認為我的建議拆除是為了再賺手術費，我們雙腳TPO手術加上一個月的住院及以後雙腳拆除骨板的所有費用比別家一次雙腳TPO的費用還低，如果有這樣的評語對我們是欠公道的，我只是把不拆骨板的缺點讓飼主知道，由飼主去決定，以免以後發生問題，例如骨癌發生再取出骨板就來不及了，而這種觀念不是只有TPO手術，希望所有骨折使用骨內金屬固定器的年輕動物，最好在骨折癒合後取出，至於老年動物在老年才動手術者可以決定不要取出，因為它的併發症是隨植入物在體內的時間越久而發生的機會越高。

選擇手術與否？手術選擇之後拆不拆骨板？ CHD是一個疼痛的疾病，很少造成不能走路，狗不能用語言表達疼痛，狗也是很能忍痛的動物，雖有疼痛，也可能不會表現出來，其實，應該說雖有疼痛，飼主可能無法觀察出來，選擇手術或保守治療也是飼主了解後做選擇，保守治療最好是不用服用藥品的情況下，狗能無痛的生活，如果需要長期服止痛劑，我並不建議。植入物在體內時間久可能產生併發症，這個併發症可能是致命性的骨癌，醫生基於所學提供建議，最後決定權還是在飼主。

以下是有關骨癌和金屬植入物留滯體內的相關研究報告，一般研究報告有相同性質的或已經報導過的，一般不會被接受刊登，據我所知骨板引起的骨癌的機會是0.12% 。

1: J Am Anim Hosp Assoc. 2005 Sep-Oct;41(5):327-31. Links 
Osteosarcoma at the site of a triple pelvic osteotomy in a dog.
• Rose BW, 
• Novo RE, 
• Olson EJ. 
Departments of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota 55108.
An osteosarcoma (OSA) involving the right pelvis was diagnosed in a 12-year-old golden retriever 11 years after triple pelvic osteotomy (TPO) surgery. The dog was presented with a 12-week history of nonweight-bearing lameness of the right hind limb. Radiographs demonstrated an aggressive bone lesion of the right ilium with profound periosteal proliferation and punctate lysis that extended along the ilium caudally and into the right ischium, with its epicenter at the level of the right TPO plate. Necropsy revealed that the entire right hemipelvis, especially the ischium, was markedly thickened and firm with irregular margins. Histopathology was consistent with a diagnosis of OSA.

1: Vet Rec. 1980 Nov 29;107(22):501-2. Links 
Internal fixation of a fractured humerus in a dog and late osteosarcoma development.
• Van Bree H, 
• Verschooten F, 
• Hoorens J, 
• Mattheeuws D. 
Five years after an intramedullary nailing of a fractured humerus a fistula developed in a dog. The nail was removed and a gross swelling developed 11 weeks later. Osteosarcoma was diagnosed.
1: J Am Vet Med Assoc. 1975 Jul 15;167(2):166-7. Links 
Osteogenic sarcoma associated with internal fracture fixation in two dogs.
1: Vet Comp Orthop Traumatol. 2005;18(3):194-8. Links 
Locking compression plate fixation of radial and tibial fractures in a young dog.
• Schwandt CS, 
• Montavon PM. 
Clinic for Small Animal Surgery of the Vetsuisse Faculty University Zurich, Zurich, Switzerland. cschwandt@vetclinics.unizh.ch
A six-month-old, male Bernese Mountain Dog in which radius-ulna and tibia-fibula concomitant fractures were treated each with a 3.5 mm Locking Compression Plate (LCP) is presented. Both fractures were approached and plated medially. The tibial fracture had to be revised with a 4.5 mm intramedullary nail and a new 3.5 mm LCP at the second post-operative day because of fixation breakdown. The follow-up radiographs taken at days 14 and 53 revealed uneventful healing of both fractures. Implants were removed 53 days after surgery.

1: Clin Orthop Relat Res. 1976 May;(116):253-7. Links 
Osteosarcoma associated with metallic implants. Report of two cases in dogs.
• Harrison JW, 
• McLain DL, 
• Hohn RB, 
• Wilson GP 3rd, 
• Chalman JA, 
• MacGowan KN. 
This is a report of two dogs in which osteosarcomas arose in association with metallic orthopedic implants. One neoplasm occurred in the distal humerus of a 12-year-old Doberman Pinscher. A stainless steel intramedullary pin had been implanted in the bone 11 years previously. Upon removal, corrosion of the pin was noted. The second neoplasm arose in the proximal tibia of a 12-year-old Irish Wolfhound. Six years previously, a fracture of the tibia had been repaired with a plate and screws made of the same type stainless steel, type 316L, by the same manufacturer. No corrosion appeared to have occured. Infection had not occured in either animal.

1: Clin Orthop Relat Res. 1976 Jul-Aug;(118):257-66. Links 
Tumors associated with metallic implants in animals.
• Sinibaldi K, 
• Rosen H, 
• Liu SK, 
• DeAngelis M. 
Eight cases of malignant tumors originating in close proximity to various metallic surgical implants which were used in the treatment of common canine and feline fractures are presented. There were 5 osteosarcomas, one fibrosarcoma and 2 undifferentiated sarcomas with the characterisitcs of malignant histiocytomas. All 8 occurred in the md shaft of the femur, humerus or radius, a most unusual location considering that almost all primary canine osteosarcomas have been found tramedullary pins, 2 with intramedullary Steinmann pins (one with cerclage wires) and one with an AO plate screws. Seven of the fractures treated had united and only one pseudoarthrosis was present where the cerclage wires were used. All implants used showed corrosion and had been in place for 6 months to 6 years prior to tumor discovery. None was infected.
PMID: 182427 [PubMed - indexed for MEDLINE]


1: J Am Vet Med Assoc. 1982 May 15;180(10):1189-96. Links 
Fracture-associated sarcoma in the dog.
• Stevenson S, 
• Hohn RB, 
• Pohler OE, 
• Fetter AW, 
• Olmstead ML, 
• Wind AP. 
Seven fracture-associated sarcomas developed in large-breed dogs after stabilization of comminuted long bone fractures with stainless steel plates and screws. In most cases, the healing pattern of the fractures was disturbed. The mean interval between fracture occurrence and tumor diagnosis was 5.5 years. Radiographically, the sarcomas were typified by smooth-bordered subperiosteal proliferation and soft tissue mineralization. Cortical destruction was variable. Several histologic subtypes of osteosarcoma were seen. Four sarcomas had a marked inflammatory cell component and 5 of the dogs had clinical evidence of chronic infection. These findings were similar to those in 35 previously reported fracture-associated sarcomas, even though many types of fixation devices in addition to plates, as well as no fixation at all, were represented in these cases. Fracture-associated sarcomas most frequently were found to be diaphyseal, and the femur accounted for almost half of the sarcomas reported.


1: J Am Vet Med Assoc. 2005 Nov 15;227(10):1613-7, 1591. Links 
Comment in: 
J Am Vet Med Assoc. 2006 Jan 15;228(2):194-5; author reply 195. 
J Am Vet Med Assoc. 2006 Jan 15;228(2):195; author reply 196. 
Sarcoma of the proximal portion of the tibia in a dog 5.5 years after tibial plateau leveling osteotomy.
• Boudrieau RJ, 
• McCarthy RJ, 
• Sisson RD Jr. 
Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA 01536, USA.
Osseous neoplasia was identified in the proximal portion of the tibia and distal portion of the femur in an 11.75-year-old spayed female German Shepherd Dog. A tibial plateau leveling osteotomy, followed by application of a metal plate, had been performed on the affected limb 5.5 years earlier. Areas of osteolysis and periosteal proliferation were seen radiographically, with an intense area of osteolysis directly beneath the metal plate. Histologically, the tumor was identified as a poorly differentiated sarcoma. Extracellular and intracellular debris was seen histologically, and energy-dispersive x-ray analysis confirmed that this debris was metallic. On visual examination, areas of the underside of the metal plate that had been in contact with bone had a dull, roughened appearance, and scanning electron microscopy of these areas revealed multiple corrosion pits. The plate was strongly magnetic, suggesting that it contained ferrite, and metallographic examination of the plate revealed substantial differences in the chemical makeup of various parts of the plate. Microstructure analysis revealed that the plate consisted of an austenite matrix with a large fraction of ferrite. The plate was determined to be a cast 316L stainless steel implant, but it did not meet American Society for Testing Materials standards for implant-grade materials. The possibility that implant corrosion might have played a role in tumor development is of concern; however, a definitive association was not established.


Osteosarcoma associated with a metal implant.
• Kumar K.
Department of Orthopaedics, Krishna Institute of Medical Sciences, Karad, Maharashta, India.
An osteosarcoma developed in a boy, 16 years of age, 9 years after staples had been inserted in the region of the lower femoral epiphysis. The possible association between the implant and the tumour is discussed.

1: J Small Anim Pract. 2005 Sep;46(9):457-9. Links 
What is your diagnosis? Fracture/implant-associated osteosarcoma following TPLO procedures.
• Straw M.
• 
1: J Am Vet Med Assoc. 1982 Nov 1;181(9):885-90.

Osteomyelitis and neoplasia associated with use of the Jonas intramedullary
splint in small animals.

Sinibaldi KR, Pugh J, Rosen H, Liu SK.

In 11 cases (10 dogs, 1 cat) in which fractures were repaired with the Jonas intramedullary splint, osteomyelitis developed in 6 and tumors developed in 5. In each case, the tumor originated in close proximity to the splint, at the midshaft of the femur or radius. All implants had been in place for 6 months to 6 years in the case of tumors, and for 4 months to 6 years in the cases involving osteomyelitis. Corrosion was evident in all retrieved implants. The corrosion was attributed to fabrication of the devices with a corrosion-susceptible stainless steel, AISI type 304. The corrosion was believed to have been accelerated by stress effect due to differences in cold work of the sleeve and pin and the difference in composition between the sleeve and spring of the splint. It was concluded that fixation of fractures in small animals should not be performed with the Jonas intramedullary splint.

1: J Small Anim Pract. 1997 Jun;38(6):263-7.

Osteosarcoma following total hip arthroplasty in a dog.

Murphy ST, Parker RB, Woodard JC.

Department of Small Animal Clinical Sciences, University of Florida, College of
Veterinary Medicine, Gainesville 32610-0126, USA.

Osteosarcoma involving the distal right femur was diagnosed in a nine-year-old female neutered Rottweiler seven years after total hip arthroplasty had been performed on that limb. The findings were consistent with a primary bone tumour and pathological fracture of the right femoral condyle with loosening of the orthopaedic implant and fracture of the polymethylmethacrylate at the distal aspect of the femoral component. Possible hypotheses to explain the association of osteosarcoma with total hip arthroplasty suggest that the neoplastic process was the result of some derangement of host tissue and the healing process or that the implants or their by-products were carcinogenic. Given the large number of total hip arthroplasties that are routinely performed in dogs, the development of a malignant lesion appears to be an extraordinary complication and may be completely coincidental.

PMID: 9200118 [PubMed - indexed for MEDLINE]


1: Vet Surg. 1996 Jan-Feb;25(1):70-4.

Osteosarcoma eight years after total hip arthroplasty.

Roe SC, DeYoung D, Weinstock D, Kyles A.

Department of Companion Animal and Special Species Medicine, College of
Veterinary Medicine, North Carolina State University, Raleigh, USA.

This report presents a case of osteosarcoma of the femoral diaphysis associated
with chronic stimulation of the area by an unstable femoral prosthesis after
total hip arthroplasty performed 8 years previously. The pathogenesis of this
transformation may be similar to that proposed for fracture-associated sarcoma.
Neoplasia should be considered as a possible late complication of total hip
arthroplasty.

PMID: 8719088 [PubMed - indexed for MEDLINE]


1: Vet Surg. 1999 Jan-Feb;28(1):54-60.

Osteosarcoma at the site of bone infarction associated with total hip
arthroplasty in a dog.

Marcellin-Little DJ, DeYoung DJ, Thrall DE, Merrill CL.

Department of Companion Animal and Special Species Medicine, College of
Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.

OBJECTIVE: To report the occurrence of medullary bone infarction in both femoral canals after bilateral total hip arthroplasty (THA) and the subsequent unilateral development of an osteosarcoma at the site of bone infarction. STUDY DESIGN: Clinical report. ANIMAL POPULATION: An 8-month-old neutered male Samoyed dog. METHODS: Serial physical and radiographic examinations performed at 1, 2, 3, and 5 years after THA. Bone biopsy specimens of the right distal femoral metaphysis were taken 5 years after THA, and a complete necropsy was performed at the time of euthanasia. RESULTS: Bilateral medullary bone infarction was visible in the femoral canals 1 year after THA and remained visible on subsequent evaluations. An osteosarcoma developed in the right distal femoral metaphysis at the site of infarction, 5 years after THA, and was found to have metastasized widely throughout the body. CONCLUSION: Bone infarction may occur in the femoral canal after canine THA. CLINICAL RELEVANCE: Bone infarction maybe a redisposing factor for the development of osteosarcoma in the femora of dogs with THAs.

1: Mod Pathol. 2001 Oct;14(10):969-77.

Orthopaedic implant-related sarcoma: a study of twelve cases.

Keel SB, Jaffe KA, Petur Nielsen G, Rosenberg AE.

The James Homer Wright Pathology Laboratories, Massachusetts General Hospital,
Harvard Medical School, Boston, Massachusetts 02114, USA.

Sarcoma developing in association with a metallic orthopaedic prosthesis or
hardware is an uncommon, but well recognized complication. We review 12 cases of
sarcomas arising in bone or soft tissue at the site of orthopaedic hardware or a
prosthetic joint. Nine patients were male, and three were female. Their ages
ranged from 18 to 85 (mean 55) years at the time of diagnosis of the malignancy.
Five patients had undergone hip arthroplasty for degenerative joint disease,
four had been treated with intramedullary nail placement for fracture, two had
staples placed for fixation of osteotomy, and one had hardware placed for
fracture fixation followed years later by a hip arthroplasty. The time interval
between the placement of hardware and diagnosis of sarcoma was known in 11 cases
and ranged from 2.5 to 33 (mean 11) years. The patients presented with pain,
swelling, or loosening of hardware and were found to have a destructive bone or
soft tissue mass on radiography. Two sarcomas were located primarily in the soft
tissue and 10 in bone. Seven patients developed osteosarcoma, four malignant
fibrous histiocytoma, and one a malignant peripheral nerve sheath tumor. All
sarcomas were high grade. Three patients had metastatic disease at the time of
diagnosis. Follow-up was available on eight patients: five patients died of
disease 2 months to 8 years (mean 26 months) after diagnosis; two patients died
without evidence of disease 7 and 30 months after diagnosis; and one patient is
alive and free of disease 8 years after diagnosis. Sarcomas that occur adjacent
to orthopaedic prostheses or hardware are of varied types, but are usually
osteosarcoma or malignant fibrous histiocytoma. They behave aggressively and
frequently metastasize. Clinically, they should be distinguished from
non-neoplastic reactions associated with implants, such as infection and a
reaction to prosthetic wear debris.

PMID: 11598166 [PubMed - indexed for MEDLINE]

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