Abstract
The arthroscopic approach and anatomy of the bovine femoropatellar and femorotibial joints are described. A 4-mm diameter, 15-cm long arthroscope with a 30° forward angle view was used. The structures viewed were recorded according to the position of the arthroscope within the joint. The femoropatellar joint was best accessed via a lateral approach, between the middle and lateral patellar ligaments. The axial portion of the medial femorotibial joint was viewed from a medial approach between the middle and medial patellar ligaments and the abaxial portion was viewed from a lateral approach between the middle and the lateral patellar ligaments. The axial portion of the lateral femorotibial joint was viewed from a lateral approach between the middle and the lateral patellar ligaments and the abaxial portion was viewed from a medial approach between the middle and medial patellar ligaments. The results of this study provide guidelines regarding the location of arthroscopic portals to evaluate precisely different areas of the stifle in cattle.
Résumé
Détermination de l’anatomie arthroscopique normale des articulations fémoropatellaire, et fémorotibiales, compartiments craniaux, chez les bovins. Les approches arthroscopiques et l’anatomie des articulations fémoropatellaire et fémorotibiales des bovins sont décrites dans cet article. Un arthroscope de 4 mm de diamètre et d’une longueur de 15 cm avec un angle de visionnement de 30 degré a été utilisé. La position de l’arthroscope a été notée pour chaque structure visualisée. L’articulation fémoropatellaire était pénétrée par une approche latérale, entre les ligaments patellaires médian et latéral. La portion axiale de l’articulation fémorotibiale médiale était pénétrée par une approche médiale entre les ligaments patellaire médian et médial et la portion abaxiale était pénétrée par une approche latérale entre les ligaments patellaires médian et latéral. La portion axiale de l’articulation fémorotibiale latérale était pénétrée par une approche latérale entre les ligaments patellaires médian et latéral et la portion abaxiale était pénétrée par une approche médiale entre les ligaments patellaires médian et médiale. Les résultats de cette étude s’avère être un guide afin d’utiliser la meilleure approche arthroscopique pour évaluer précisément certaines structures du grasset bovin.
(Traduit par les auteurs)
Introduction
Minimally invasive surgery continues to gain popularity in veterinary medicine. Synovial structures surrounding joints and tendons have been well-described in horses (1,2). In the mid-1980’s and 1990’s, the use of arthroscopy to treat joint diseases was described in cattle (3,4). The techniques described for joints and tendon sheaths of cattle were similar to those described for use in horses (5). Developmental orthopedic disease, septic synovitis, and ligamental injury are diseases suitable for arthroscopic evaluation in cattle (3,4,6–8). However, arthroscopy has not been accepted widely for use in cattle for various reasons including cost, clinician experience, equipment limitations, and a perception that such technology has limited usefulness in cattle. Breeding bulls, show cattle, and cows perceived to have genetic value are more likely to be selected for arthroscopic surgery (7). The stifle is one of the joints examined most frequently by arthroscopy in cattle (7). The stifle of cattle is composed of the femoropatellar joint and the lateral and medial femorotibial joints. The femoropatellar joint is composed of the patella, trochlear groove, trochlear ridges of the distal femur, and lateral and medial cul-de-sacs. It qualifies as a sledge joint. The femorotibial joints are composed of the femoral condyles, the tibial condyles and median eminences, and the menisci. They are condylar joints (9,10). Medial, middle, and lateral patellar ligaments join the distal aspect of the patella to the proximal tibia (Figure 1). The 3 joints communicate with each other in 57% of cattle (10). The femoropatellar joint and the medial femorotibial joint always communicate.
Figure 1.
Macroscopic anatomy of the bovine stifle. The skin, the subcutaneous tissue, and the fat pad under the patellar ligaments have been partially removed. MM — medial meniscus, LM — lateral meniscus, PL — patellar ligament.
Clinical experience performing arthroscopy of the stifle joint of cattle revealed that the anatomy of cattle differs sufficiently from the horse so as to limit the usefulness of the positioning of arthroscopic portals described in horses. The objectives of this study were to describe the arthroscopic approach and anatomy of the femoropatellar and femorotibial joints in cattle.
Materials and methods
Ten legs of 5 adult cattle euthanized for reasons not related to a stifle injury were retrieved and evaluated. The legs were disarticulated at the level of the coxofemoral joint to preserve the soft tissue around the stifle. The arthroscopic evaluation was performed no later than 24 h after the death of the animal. A 12.5-mm hole was drilled in the proximal diaphysis of the femur in a lateral-to-medial plane. A 6.2-mm metallic rod was inserted through the hole and secured to 2 square boards placed medially and laterally to the leg. This setup allowed positioning of the leg as if the animal was in dorsal recumbency without the need for an assistant to hold the leg. The angle of the stifle joint at which the arthroscopy was performed was recorded.
A standard 4-mm diameter, 15-cm long arthroscope with a 30° forward angle view (Karl Storz Endovision, Charlton, Massachusetts, USA) was used to evaluate the femoropatellar and the femorotibial joints. A video camera and a light cable were attached to the arthroscope and were connected to a digital recorder (Karl Storz Endovision) to capture images and videos of the joint evaluation. A nitrogen-driven flutter valve pump was connected to the arthroscopic sleeve and water was used to distend the joint during the arthroscopic evaluation. Images and videos recorded during each evaluation were reviewed to evaluate the structures viewed.
The femoropatellar joint was entered first, without joint distension, followed by the medial femorotibial joint and the lateral femorotibial joint. The medial femorotibial joint was entered with the joint still under tension from the femoropatellar evaluation. The lateral femorotibial joint was distended with 60 mL of water to facilitate introduction of the cannula. The locations of the portal were determined according to their relation with the patellar ligament, the proximal aspect of the tibia, and the distal aspect of the patella.
Following arthroscopy, the joints and the surrounding soft tissue were dissected to macroscopically evaluate the structures viewed during the procedure.
Results
Ten stifles of 5 adult cattle were evaluated. The median age and weight of cattle were 5 years (range: 3 to 7 y) and 600 kg (range: 400 to 650 kg). Four dairy and 1 beef cow were used.
With the leg in extension, the femoropatellar joint (Figure 2) was evaluated first. No distension of the joint was needed to introduce the arthroscopic sleeve and the conical obturator. The medial trochlear ridge was prominent and in intimate contact with the patella. Thus, initial entry into the femoropatellar joint was most easily done from a lateral approach. Using a No. 11 scalpel blade, a 10-mm incision was made through the skin, the superficial and deep fascia, midway between the distal end of the patella and the tibial crest, between the middle and lateral patellar ligaments. The sleeve and its conical obturator were orientated at a 45° angle between the patella and the femur. The correct placement of the sleeve was evaluated by removing the obturator and inserting the arthroscope. When cartilage was viewed, the joint was distended. The distal end of the patella was viewed lying in the trochlear groove. The axial and abaxial aspect of the lateral trochlear ridge, the lateral femoropatellar cul-de-sac, and the lateral aspect of the patella were evaluated. The trochlear groove and the axial aspect of the medial trochlear ridge were viewed. The abaxial aspect of the medial trochlear ridge, the medial femoropatellar cul-de-sac, and the medial aspect of the patella were better viewed if the scope was inserted from between the medial and middle patellar ligaments. The scope was positioned between the patella and the femur from the lateral aspect and the proximal aspect of the trochlear groove and the suprapatellar cul-de-sac were evaluated. The scope was rotated 180° to evaluate the articular surface of the patella. All the aforementioned structures were seen in all 10 joints. A summary of the structures visualized from each portal in the femoropatellar joint is presented in Table 1.
Figure 2.
Localization of the arthroscopic portal between the middle and lateral patellar ligament and orientation of the arthroscope (large blue arrow) to enter the femoropatellar joint. A — Suprapatellar pouch (black arrow) and patella. B — Lateral trochlear ridge (black arrow) and lateral femoropatellar cul-de-sacs. C — Distal aspect of the patella (black arrow) and trochlear ridge. D — Mid portion of the trochlear groove (black arrow) and mid portion of the patella. E — Medial trochlear ridge (black arrow).
Table 1.
Summary of the structures viewed through each arthroscopic portal during the evaluation of the bovine stifle
| Joint | Arthroscopic portal | Structures viewed |
|---|---|---|
| Femoropatellar | Between lateral and middle patellar ligaments | Patella Suprapatellar cul-de-sac Lateral and medial (axial) trochlear ridge Trochlear groove Lateral femoropatellar cul-de-sac |
| Between medial and middle patellar ligaments | Patella Lateral (axial) and medial trochlear ridge Trochlear groove Medial femoropatellar cul-de-sac |
|
|
| ||
| Medial femorotibial | Between medial and middle patellar ligaments | Medial femoral condyle (axial) Femoral attachment of CauCL Tibial intercondylar eminence Tibial attachment of CCL Medial meniscus (axial) |
| Between lateral and middle patellar ligaments | Medial femoral condyle (cranial and abaxial) Medial meniscus (abaxial) |
|
| Between lateral and middle patellar ligaments | Lateral femoral condyle (axial) Lateral tibial condyle (axial) Lateral meniscus (axial) Cranial tibial ligament of lat meniscus Tibial attachment of CCL Origin of the LDE tendon |
|
|
| ||
| Lateral femorotibial | Between medial and middle patellar ligaments (proximal orientation) | Lateral femoral condyle (axial, cranial, abaxial) Origin of the LDE tendon Tendon of popliteal muscle Lateral meniscus (abaxial) |
| Between medial and middle patellar ligaments (distal orientation) | LDE tendon Lateral tibial condyle (cranial) Extensor sulcus |
|
CauCL — caudal cruciate ligament, CCL — cranial cruciate ligament, LDE — long digital extensor.
The distal portion of the trochlear ridge was difficult to evaluate because of abundant synovium and difficultly in orienting the scope distally without exiting the joint. Mild flexion of the joint helped to evaluate the most distal aspect of the trochlear groove.
Joint distension was maintained to facilitate introduction of the scope into the medial femorotibial joint (Figure 3). The leg was repositioned to create a 60° angle of flexion of the stifle. The skin incision, between the medial and middle patellar ligaments, used to evaluate the medial aspect of the femoropatellar joint, was used to start the evaluation of the medial femorotibial joint. The superficial and deep fasciae were incised using a No. 11 scalpel blade. The sleeve and the conical obturator were oriented toward the cranial and axial aspect of the medial femoral condyle. Proper placement of the sleeve was first evaluated by the flow of fluids after removal of the obturator and then by viewing cartilage with the arthroscope. From this position the axial aspect of the medial femoral condyle, the caudal cruciate ligament in the intercondylar space, the tibial intercondylar eminence, the location of the tibial attachment of the cranial cruciate ligament (extrasynovial and surrounded by fat) and the axial aspect of the medial meniscus were viewed. The abaxial aspect of the medial femoral condyle and meniscus were better viewed via a more lateral approach. The sleeve and scope in the femorotibial joint were kept in place to maintain joint distension. Through the same skin incision used to evaluate the lateral aspect of the femoropatellar joint, between the middle and the lateral femoropatellar ligament, the superficial and deep fasciae were incised with a No. 11 scalpel blade. Another sleeve and conical obturator were then inserted and oriented toward the cranial and abaxial aspect of the medial tibial condyle. Proper placement of the sleeve was evaluated by flow of fluids after removal of the obturator and by viewing cartilage with the arthroscope. From that portal, the cranial and abaxial aspect of the medial femoral condyle and the abaxial aspect of the medial meniscus could be viewed. In 7 of 10 cases, it was not possible to view the medial meniscus from either approach of the joint because of extensive synovium. All the other structures were seen in all 10 joints from these approaches. A summary of the structures visualized from each portal in the medial femorotibial joint is presented in Table 1.
Figure 3.
Localization of the arthroscopic portal between the middle and lateral patellar ligaments and orientation of the arthroscope (large yellow arrow) to evaluate the abaxial aspect of the medial femorotibial joint. Localization of the arthroscopic portal between the middle and medial patellar ligaments and orientation of the arthroscope (large blue arrow) to evaluate the axial aspect of the medial femorotibial joint. A — Proximal aspect of the caudal cruciate ligament (black arrow) and axial aspect of medial femoral condyle (black dotted arrow). B — Tibial intercondylar eminence (black arrow) and medial femoral condyle (black dotted arrow). C — Medial meniscus (black arrow) and medial femoral condyle (black dotted arrow).
The lateral femorotibial joint (Figure 4) was the most difficult joint to evaluate. Distension of the joint with 60 mL of water prior to insertion of the sleeve was helpful to insure safe and proper placement of the arthroscope. The skin incision used to scope the axial portion of the medial femorotibial joint, between the middle and medial patellar ligaments, was used to scope the abaxial portion of the lateral femorotibial joint. The superficial and deep fasciae were incised using a No. 11 scalpel blade. The sleeve and conical obturator were introduced and oriented toward the cranial and abaxial aspect of the lateral tibial condyle. The arthroscope was introduced through the sleeve to evaluate proper placement within the joint. The joint was further distended to allow proper evaluation of the structures. From this approach, the axial aspect of the lateral femoral condyle and the origin of the long digital extensor (LDE) tendon were viewed. By passing the scope under the LDE, the abaxial aspect of the lateral femoral condyle, the insertion of the tendon of the popliteal muscle on the femoral condyle, and the abaxial aspect the lateral meniscus were viewed. The sleeve and the scope were left in place to maintain joint distension. The skin incision used to scope the abaxial portion of the medial femorotibial joint, between the middle and lateral patellar ligaments was used to scope the axial portion of the lateral femorotibial joint. The superficial and deep fasciae were incised using a No. 11 scalpel blade. The sleeve and conical obturator were introduced and oriented toward the cranial and axial aspect of the lateral femoral condyle. Proper placement of the sleeve was confirmed by the flow of fluids and the arthroscopic visualization of cartilage. From this approach, the axial aspect of the lateral femoral condyle, the tibial condyle and the axial aspect of the lateral meniscus were viewed. The cranial tibial ligament of the lateral meniscus and the tibial attachment of the cranial cruciate ligament (extrasynovial surrounded by fat) were also viewed from this approach. All the aforementioned structures were viewed in all 10 joints from those approaches.
Figure 4.
Localization of the arthroscopic portal between the middle and lateral patellar ligaments and orientation of the arthroscope (large yellow arrow) to evaluate the axial aspect of the lateral femorotibial joint. Localization of the arthroscopic portal between the middle and medial patellar ligaments and orientation of the arthroscope (large blue arrow) to evaluate the abaxial aspect of the lateral femorotibial joint. Localization of the arthroscopic portal between the middle and medial patellar ligaments and orientation of the arthroscope (large green arrow) to evaluate the synovial cul-de-sacs at the level of the extensor sulcus of the tibia. A — Origin of long digital extensor tendon (black arrow) and lateral femoral condyle (black dotted arrow). B — Origin of popliteal muscle (black arrow) and lateral femoral condyle (black dotted arrow). C — Lateral meniscus (black arrow) and lateral femoral condyle (black dotted arrow). D — Distal aspect of long digital extensor tendon (black arrow). E — Long digital extensor tendon (black arrow). F — Lateral meniscus (black arrow) and lateral femoral condyle (black dotted arrow). G — Origin of long digital extensor tendon (black arrow) and lateral femoral condyle (black dotted arrow).
The lateral femorotibial joint in cattle is composed of a prominent synovial cul-de-sac at the level of the extensor sulcus of the tibia surrounding the tendinous portion of the long digital extensor and the peroneus tertius muscles. To evaluate that cul-de-sac, the sleeve and conical obturator were introduced from the incision between the middle and the medial patellar ligaments and were orientated ventrally to the cranial and abaxial aspect of the lateral tibial condyle. From that entry port, the long digital extensor tendon and the cranial aspect of the tibial condyle were viewed in all 10 cases. A summary of the structures visualized from each portal in the lateral femorotibial joint is presented in Table 1.
Discussion
The technique used in this study allowed evaluation of the femoropatellar joint and cranial aspect of the medial and lateral femorotibial joints in all 10 stifles. The anatomical landmarks used to insert the scope into the femoropatellar joint are similar to those used in horses (5,10–13). However, the thick fat pad surrounding the patellar and collateral ligaments render the localization of those structures difficult, thus making localization of the landmarks for the portal incision more difficult. After distension of the femoropatellar joint, the proximal aspect of the joint was easily evaluated. However, the distal aspect of the joint was difficult to evaluate because of the abundant synovium covering the trochlear ridge. Partial flexion was helpful to expose some of the distal aspect of the trochlear ridge. The angle needed to scope the proximal aspect of the joint, the thick fat pad, and thick joint capsule of the bovine stifle made pivoting the scope difficult and limited evaluation of the distal aspect of the trochlear ridge without damaging the scope or exiting the joint. Using a probe to retract the synovial villi or performing a partial synovectomy might have been helpful to evaluate the distal portion of the joint.
A complete evaluation of the cranial aspect of the medial femorotibial joint was difficult to perform with only 1 arthroscopic portal. The axial side of the joint (axial part of the medial trochlear ridge, proximal attachment of the caudal cruciate ligament, distal attachment of the cranial cruciate ligament, tibial intercondylar eminence, and medial meniscus), was efficiently viewed via a craniomedial approach (between the middle and medial patellar ligaments). Evaluation of the cranial and abaxial aspect of the joint (abaxial aspect of the medial femoral condyle and medial meniscus) was more efficiently done via a craniolateral approach (lateral to the middle patellar ligament). In horses, a lateral approach (lateral to the lateral patellar ligament) is frequently used (1,5,14–17). This technique allows better triangulation for surgery to be performed on the medial femoral condyle (subchondral bone cyst). In cattle, because of the thick fat pad surrounding the cranial aspect of the femorotibial joints, it was difficult to evaluate the medial femorotibial joint from a lateral approach. A longer scope might be helpful if this approach is chosen in adult cattle.
The technique described in our study shared some similarity with the cranial approach described in horses in regard to the location of arthroscopic portals (5,16). However, in horses, the femorotibial joints are entered from the distal aspect of the femoropatellar joint by creating a communication between the 2 joints. In our study, the femorotibial joints were not entered from the femoropatellar joint because only the axial aspect of each femorotibial joint would have been viewed.
The most difficult structure to view in the medial femorotibial joint was the meniscus. In most of the joints, abundant synovial villi covered the distal aspect of the joint, precluding our complete evaluation of the meniscus and its ligaments. In cattle, the medial meniscus is firmly attached to the medial collateral ligament. This anatomical feature predisposes the meniscus to trauma (18,19). If diagnostic arthroscopy is performed to evaluate the meniscus, a partial synovectomy would be needed to improve viewing and treatment.
Arthroscopic evaluation of the cranial aspect of the lateral femorotibial joint was difficult. The prominent long digital extensor tendon made insertion of the scope difficult. Adequate joint distension was essential to ensure proper placement of the scope. We had difficulty evaluating the joint with only 1 arthroscopic portal. The abaxial portion of the joint (cranial and abaxial portion of the lateral femoral condyle, origin of the popliteal muscle on the lateral femoral condyle and abaxial portion of the lateral meniscus) was better evaluated from a craniomedial approach between the middle and medial patellar ligaments. The axial portion of the joint (axial aspect of the lateral femoral condyle, long digital extensor tendon origin, distal portion of the cranial cruciate ligament, axial portion of the lateral tibial condyle, and axial portion of the lateral meniscus) was better viewed from a craniolateral approach between the middle and lateral patellar ligament. In horses, a similar approach to the one described to view the abaxial portion of the joint is used (5). Compared to the medial meniscus, the body of the lateral meniscus was easier to view.
Two arthroscopic portals were necessary to adequately evaluate the cranial aspect of the medial and lateral femorotibial joints. The large fat pad and the thick fibrous joint capsule of the bovine stifle restricted manipulation of the scope and prevented complete evaluation of the joint from a single arthroscopic port. Axial structures within each joint were better viewed from an arthroscopic port located immediately proximal to the structures. The direct viewing portal to the structures would likely interfere with surgical manipulations of those structures from this approach. More forceful distention of the joint capsule might have improved manipulation of the scope. Also, cadaver legs may have been more difficult to manipulate during arthroscopy because of the loss of elasticity of the joint capsule. In vivo conditions are expected to ease manipulation of the scope and might reduce or eliminate the need for 2 skin portals per joint. However, despite the fact that 2 arthroscopic portals were needed to evaluate both femorotibial joints, only 2 skin incisions were necessary. The same 2 skin incisions were used along with different angulations of the scope to evaluate all 3 joints of the bovine stifle. Decreasing the number of skin incisions could decrease the morbidity associated with the procedure in clinical cases.
Septic arthritis of the stifle is common in cattle (20,21). Cattle having genetic value may merit arthroscopy to perform arthroscopic lavage, debridement, and partial synovectomy as has been described in horses (22,23). This procedure is expected to improve the prognosis for survival and return to normal limb usage. The technique described in this study allows the use of 2 skin incisions to evaluate all 3 joints forming the stifle. If debridement is needed 2 other skin incisions can be created laterally and medially into the lateral and medial femorotibial joints. Those portals are created under arthroscopic guidance to avoid damaging the underlying structures. For the femoropatellar joint, the skin incision created between the middle and the medial patellar ligament can be used to gain access to the joint for debridement.
This study provides guidelines regarding the location of arthroscopic portals to evaluate different portions of the stifle joint in cattle. However, during disease states the normal anatomy of the joints may change and the location of the arthroscopic portal may vary. Therefore, it will be important to evaluate the aforementioned technique in clinical cases. CVJ
Footnotes
Presented as a poster at the ACVS Symposium, Chicago, Illinois, October 2007.
Use of this article is limited to a single copy for personal study. Anyone interested in obtaining reprints should contact the CVMA office (hbroughton@cvma-acmv.org) for additional copies or permission to use this material elsewhere.
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