pISSN 1598-298X / eISSN 2384-0749 J Vet Clin 32(3) : 251-254 (2015)
http://dx.doi.org/10.17555/jvc.2015.06.32.3.251
251
Arthroscopy for the Diagnosis and Treatment of Failed Trochleoplasty in a Dog
Junho Hwang*, Suyoung Heo*, Bumseok Kim*, Sanghoon Lee*, Seongmok Jeong** and Haebeom Lee**1
*College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, Korea
**College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, Korea (Accepted: April 09, 2015)
Abstract : A 3-year-old castrated male Spitz dog (8.4 kg) was referred for hindlimb lameness. The dog had undergone corrective surgery for bilateral medial patellar luxation 6 weeks prior to presentation. Intermittent lameness of both hind limbs was evident on general inspection. Physical examination revealed moderate pain and crepitus upon flexion and extension of the stifle joints. Radiography revealed features consistent with distal deviation of the cartilage flaps and effusion in both stifle joints. Detachment and deviation of both osteochondral blocks were suspected based on the physical and radiographic findings. Arthroscopy confirmed failed osteochondral blocks (right 1.5 cm× 0.9 cm × 0.2 cm, left 1.3 cm× 0.9 cm × 0.1 cm), which were removed. After removal of the osteochondral blocks, the stepped trochlear grooves were located and debrided using an arthroscopic burr, to prevent patellar tracking disorder. The dog resumed normal ambulation without medial patellar luxation 2 weeks postoperatively, and there were no complications.
Arthroscopy is an effective surgical modality for the diagnosis and treatment of canine joint disorders. It offers a magnified view of the joint, which allows accurate evaluation of intra-articular structures. In addition, arthroscopic surgery can reduce the postoperative complications associated with surgical wound.
Key words : Medial patellar luxation, Trochleoplasty, Athroscopy, Dog.
Introduction
Patellar luxation is a common cause of lameness in small- breed dogs, with medial patellar luxation found in 95% and lateral luxation in 5% of cases (8). Medial patellar luxation is associated with an abnormal extensor mechanism of the quadriceps muscle and abnormal skeletal structure. The chief complaints are pain and lameness. Dogs with intermittent luxation commonly have a history of an occasional skipping gait, but use the limb normally most of the time. Dogs with severe luxation may have great difficulty walking or may move in a crouched position with both limbs partially flexed, while some dogs appear to have a normal walking gait. Phys- ical signs associated with this disorder vary with the degree or grade of luxation. Radiographic examination can be use- ful for documenting luxation and assessing the degree of degenerative change in the stifle joint, and is critical for iden- tifying skeletal abnormalities and patellar dislocation (13).
Surgical correction of medial patellar luxation is based on realignment of the quadriceps mechanism and stabilization of the patella within the trochlear groove of the femur (13). There are many surgical techniques such as soft tissue and bone reconstructive procedure for stabilizing the femoropatellar joint (7,16). The most common surgical procedures, which are performed alone or in combination, are as follows: abra- sion arthroplasty, trochleoplasty (block or wedge recession), tibial tuberosity transposition, corrective osteotomy, medial
retinacular release, lateral retinacular imbrication, and antiro- tational suture (17).
Trochlear block recession is the most common and gen- eral technique. This is a cartilage-sparing technique that was developed to achieve adequate trochlear depth and width, maximize preservation of the hyaline articular cartilage, and provide secure fixation of the osteochondral autograft (17).
Complications of this technique are rare. A few studies have reported migration of the trochlear block and fracture of a trochlear ridge (4,5).
Arthroscopy is defined as endoscopy of a joint. Contempo- rary small animal arthroscopy is performed most commonly in the dog and rarely in the cat, with the most frequently explored joints being the shoulder, elbow, and stifle. Docu- mented advantages of small animal arthroscopy include decreased patient morbidity, faster recovery times, decreased complication rates, improved functional outcomes, decreased anesthesia and surgery times, decreased hospitalization time, and enhanced client satisfaction (10).
To our knowledge, there are no known case reports address- ing the use of arthroscopy for the diagnosis and treatment of failed trochleoplasty in dogs. The purpose of this report is to describe the application of arthroscopy to the diagnosis and simultaneous treatment of trochlear block migration, which was an unusual complication following surgery for patellar luxation.
Case
A 3-year-old castrated male Spitz dog (8.4 kg) was
1Corresponding author.
E-mail: [email protected]
252 Junho Hwang, Suyoung Heo, Bumseok Kim, Sanghoon Lee, Seongmok Jeong and Haebeom Lee
referred for hindlimb lameness. The dog had undergone cor- rection of bilateral medial patellar luxation 6 weeks prior to presentation. Intermittent lameness of both hindlimbs was evident on general inspection. Physical examination revealed moderate pain and crepitus upon flexion and extension of the stifle joints and decreased range of motion. Gait examination found intermittent bilateral weight-bearing lameness of the hindlimbs, with a lameness score of 1/5 (12). Radiography revealed features consistent with distal deviation of the carti- lage flaps and joint effusion in both stifle joints (Fig 1).
Based on the physical and radiographic findings, we sus- pected detachment and deviation of both osteochondral blocks and performed exploratory arthroscopy. Cefazoline and tram- adol were administrated intravenously at doses of 22 mg/kg and 3 mg/kg, respectively. General anesthesia was induced
using propofol at a dose of 6 mg/kg and was maintained by isoflurane. With the dog in dorsal recumbency, both hind- limbs were prepared for aseptic arthroscopy. There was crep- itus upon flexion and extension of both stifle joints.
Arthroscope, egress, and instrument portals were established at each joint. Arthroscopy revealed obvious inflammation and hyperplasia of the synovium and deviation of the osteochon- dral blocks (right 1.5 cm× 0.9 cm × 0.2 cm, left 1.3 cm
× 0.9 cm × 0.1 cm) on the proximal patellar ridge. After arthroscopic removal of the osteochondral blocks (Fig 2A), Fig 1. Preoperative radiographs showing distal deviation of the
cartilage flaps. Right stifle joint (A). Left stifle joint (B).
Fig 2. Photographs showing removal of an osteochondral block (A), stepped trochlear groove (B, arrow), and stepped trochlear groove (arrow) after debridement using an arthroscopic burr to prevent patellar tracking disorder (C, arrow), and magnified view after debridement of the trochlear groove (D).
Fig 3. Photomicrographs of changes in the subchondral bone of the osteochondral blocks (A, B, left stifle joint; C, D, right stifle joint), hematoxylin and eosin staining. Subchondral bone changes include proliferation of fibrous tissue (arrows) in the deep within subchondral bone (A). Higher magnification of (A) shows destruction of subchondral bone (arrows) with prolifera- tion of fibrous tissue (B). Destruction and calcification (arrows) of subchondral bone with proliferation of fibrous tissue (C).
Higher magnification of (C) shows destruction of subchondral bone and increased numbers of osteoclasts (arrows) adjacent to proliferation of mesenchymal tissue (D).
Fig 4. Postoperative radiographs 6 weeks after arthroscopic removal of the osteochondral block. Right stifle joint (A). Left stifle joint (B).
Arthroscopy for the Diagnosis and Treatment of Failed Trochleoplasty in a Dog 253
the stepped trochlear grooves (Fig 2B) were debrided using an arthroscopic burr to prevent abnormal patellar tracking (Fig 2C). Lavage of the joints was performed using lactated Ringer’s solution to wash out the inflammatory mediators and residual debris from the osteochondral blocks. Closures were single skin sutures placed at the portal sites. The removed osteochondral blocks were submitted for histologi- cal examination (Fig 3). After surgery, the patient was administered cefazoline orally at a dosage of 22 mg/kg twice a day for 3 days and meloxicam orally at 0.1 mg/kg once a day for 3 days. The patient was discharged and leash walk- ing the day after surgery. Two weeks after the arthroscopic procedure, the function of the affected limbs was good and showed normal gait. The patient showed normal ambulation and no medial patellar luxation and radiography was taken 6 weeks after the procedure (Fig 4).
Discussion
This case report describes the successful arthroscopic man- agement of trochlear block migration, which was an unusual complication following patellar luxation surgery.
The complications and outcomes of the surgical repair of medial patellar luxation have been well documented, and include reluxation of the patella, infection, implant failure, avulsion of the tibial tuberosity, and degenerative joint dis- ease (15). Trochlear block migration can occur, but is extremely rare (1). The cause of trochlear block migration is not completely understood. However, careless management after surgery or excessive removal of subchondral bone dur- ing trochlear block recession may be causes of trochlear block migration. As the stifle is extended, the patella moves proximally within the femoral trochlea, and reduction in fem- oropatellar contact is compounded following block reces- sion, which results in reduced articular contact between the patella and the trochlear block (14). This situation may increase the risk of trochlear block migration, especially care- less management after surgery. The subchondral bone bed of trochlear block is important for successful attachment between the reimplanted trochlear block and trochlear groove of femur. Therefore, excessive removal of subchondral bone during trochlear block recession may lead to decrease union between the trochlear block and trochlear groove of femur.
Relocation or removal of the trochlear block are options for treatment of trochlear block migration. Relocation of the block can be performed if migration is found immediately after surgery. However, it is not clear how long after surgery a migrated trochlear block can be relocated. If relocation of the trochlear block is impossible, or trochlear block migra- tion is thought to be of long duration, block removal can be considered (15). Trochlear sulcoplasty should be performed after removal of the block. Trochlear sulcoplasty leads to a trochlear surface that is covered with well vascularized, highly cellular, and loose connective tissue that later reorga- nizes into dense fibrous connective tissue that resembles fibrocartilage and has an irregular surface. This technique results in complete loss of the hyaline cartilage that lines the femoral trochlea and therefore has complications. Dogs undergoing trochlear sulcoplasty were noted to have atrophy
of the quadriceps femoris muscle, palpable crepitus, and severe erosion of the articular cartilage of the patella as early as 4 weeks postoperatively (3). However, most cases undergoing trochlear sulcoplasty have acceptable joint motion and func- tion. In our case, block removal was performed instead of relocation of the block because we thought that the recipient bed of the trochlear block would again lead to a poor attach- ment between the trochlear block and trochlear groove of femur, resulting in high risk of recurrent migration of the block. Our decision was supported by the histological exam- ination, which showed subchondral bone destruction with fibrous tissue proliferation (Fig 3).
This case demonstrated that arthroscopy was a good proce- dure for many reasons. Most importantly, arthroscopy allowed direct inspection of the articular surfaces and other joint structures (8). Moreover, arthroscopy allowed diagnosis and treatment to be combined into a single procedure. Other pub- lished advantages of arthroscopy over arthrotomy include de- creased patient morbidity, a minimally invasive procedure, faster patient recovery, faster return to function, and reduced risk of infection (8). Our patient was discharged from the hospital 1 day after surgery, and the client was highly satis- fied because of the very small surgical wounds.
Conclusion
The stifle joints of our patient returned to normal function after the arthroscopic elimination of trochlear block migra- tion. Arthroscopy can be a useful tool for the diagnosis and treatment of canine joint problems.
Acknowledgement
This work was supported by Basic Science Research Pro- gram through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (NRF-2013R1A1A2009546).
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활차구 성형술이 실패한 개에서 관절경을 이용한 진단과 치료
황준호*·허수영*·김범석*·이상훈*·정성목**·이해범**1
*전북대학교 수의과대학, **충남대학교 수의과대학
요 약 : 3살 중성화된 수컷 스피츠 (8.4 kg)가 후지 파행으로 본원에 의뢰되었다. 환자는 6주전 양측 내측 슬개골 탈 구 교정술을 받았다. 육안상 양측 뒷다리의 간헐적인 파행을 보였으며 신체검사에서 슬관절의 굴신전시 염발음을 동 반한 중등도의 통증을 보였다. 방사선 검사상 양측 슬관절에서 연골편의 원위부 이탈과 함께 관절부종이 관찰되었다.
신체검사와 방사선검사를 토대로 양측 슬관절 골연골편의 분리와 이탈이 의심되었다. 관절경을 통해 이탈한 골연골편 (우측 1.5 cm × 0.9 cm × 0.2 cm, 좌측 1.3 cm × 0.9 cm × 0.1 cm)을 확인하고 제거하였다. 골연골편을 제거한 후, 슬개골 의 비정상적 움직임을 예방하기 위해 관절경을 통해 burr를 이용하여 층진 활차구를 성형해주었다. 환자는 수술 2주후 정상적인 보행을 하였으며 합병증을 보이지 않았다. 관절경은 개의 관절질환 진단 및 치료를 위한 효과적인 수단이다.
이를 통해 관절내 구조물을 확대해서 관찰 할 수 있고 정확한 진단을 할 수 있다. 게다가 관절경을 통한 수술은 일반 적인 술부에서 나타날 수 있는 술 후 합병증을 줄여 줄 수 있다.
주요어 : 내측 슬개골 탈구, 활차구성형술, 관절경, 개
