Stifle Joint Flashcards
Is Osteochondrosis/osteochondritis dissecans of the stifle joint often unilateral or bilateral?
Bilateral
Which surface of the stifle is commonly effected by Osteochondrosis/osteochondritis dissecans of the stifle joint?
Medial surface of lateral femoral condyle
How common are isolated tears of the medial or lateral collateral ligaments?
Rare - usually occur in conjunction with injury of other primary or secondary stabilisers of the stifle joint.
What type of joint is the stifle?
A complex condylar synovial joint
How many articular regions does the femur have?
3
What do the femoral lateral and medial condyles articulate with?
Proximal tibia
In cross section, what shape is the proximal tibia?
Triangle
What does the femoral trochlea articulate with?
Patella
How is the articular surface of the proximal tibia composed?
Two condyles, the lateral and medial separated by the non-articular intercondylar eminence
What lie on and are attached to their respective medial and lateral tibial condyles of the proximal tibia?
Medial and lateral menisci
What does the head of the fibula articulate with?
Caudo lateral surface of lateral tibial condyle
What is the largest sesamoid of the body?
Patella
What is the patella found within?
Tendon of insertion of the quadriceps muscle group
The patellar ligament runs from the paterlla to insert where?
On tibial tuberosity
What are the three other sesamoid bones of the stifle? Where are they?
These include the medial and lateral fabellae, which are within the medial and lateral heads of the origin of the gastrocnemius muscle, and the popliteal sesamoid, which is within the tendon of origin of the popliteus muscle at the lateral condyle of the tibia.
What are the 3 articulations of the stifle?
femorotibial joint,
the femoropatellar joint
the tibiofibular joint.
How many ligaments give primary support to the stifle?
4
What are the support ligaments of the stifle?
the medial and lateral collateral ligaments
cranial and caudal cruciate ligaments.
Which stifle ligament has strong attachments to the medial meniscus
Medial collateral ligament
What are the menisci attached to the tibi by?
Series of pairedd ligaments - the cranial and caudal meniscotibial ligaments of each menisci.
he meniscofemoral ligament of the lateral meniscus runs from and to?
From: caudal axial border of the lateral meniscus
To: the intercondylar fossa of the femur
The intermeniscal ligament is a fibrous band that extends from and to?
From: caudal side of the cranial tibial ligament of the medial meniscus
To: the cranial side of the cranial tibial ligament of the lateral mensicus.
Are cruciate ligaments intra or extra articular?
Intra articular
Are the cruciate ligaments intra or extra synovial?
Extra synovial
The cruciate ligaments are termed cranial or caudal based on….?
Tibial attachment
What does the cranial cruciate ligament prevent?
Cranial translation of the tibia
What are the two bands the cranial ligament are split into? Which is larger?
Caudolateral (larger)
Craniomedial
Is the cranial or caudal cruciate ligament larger?
Caudal
There is no cranial drawer with partial ruptures if only the A) band is torn as the B) band stabilises the stifle in both flexion and extension.
A) Caudolateral
B) Craniomedial
If only the A) band is torn there is cranial drawer when the stifle is flexed as the B) band only stabilises the stifle in extension. For this reason, it is important to assess craniocaudal stifle stability in both flexion and extension.
A) Craniomedial
B) Caudolateral
What does the caudal cruciate ligament prevent?
Caudal translation of tibia
What shape and material of the menisci of the stifle?
C shaped
What cross section shape is the stifle meniscus?
Wedge shape
Where is the mensicus of the stifle:
A) Thick?
B) Thin?
A) Thick - where attached to synovium
B) Thin - free edge axially
How much of the mensicus has a blood supply - where does this originate?
Peripheral 15-25% Originating from synovium
What forces develop from the shape and near frictionless surface of the meniscus developing from compressive forces?
Radial forces
How are the radial forces of the meniscus resisted?
Tensile (hoop) stress in the circumferentially arranged collagen fibres of the menisci
What are the roles of the menisci of the stifle? (2)
- 2ry stabiliser
- Transfer load across stifle
What does the function of the stifle menisci rely on?
Intact peripheral rim (hoop stress)
What are the 2 surgical approaches to the stifle?
Lateral and medial
When approaching the stifle on the lateral aspect, take care to avoid injury to which structure when entering joint capsule?
Long digital extensor tendon
On the lateral approch to the patella; which way is patella luxated?
Medially
Which of the following statements pertaining to the long digital extensor muscle is correct?
A) It originates at the extensor fossa of the lateral femoral condyle and inserts on digits II through V and its origin is intra-articular.
B) It originates at the extensor fossa of the lateral femoral condyle and inserts on digits II through V and its origin is extra-articular.
C) It originates at the extensor fossa of the medial femoral condyle and inserts on digits II through V and its origin is intra-articular.
D) It originates at the extensor fossa of the medial femoral condyle and inserts on digits II through V and its origin is extra-articular.
A) It originates at the extensor fossa of the lateral femoral condyle and inserts on digits II through V and its origin is intra-articular.
Lateral approach to the stifle:
A) Where is the skin incision? Including where it is extended to?
B) How is the lateral fascia incised?
A) Make a skin incision over the tibial tuberosity lateral to the patellar ligament and continue it proximally to the level of the patella and above following the cranial border of the femur.
B) starting opposite the distal pole of the patella and a few millimetres lateral to the patellar ligament and continuing distally to the tibia
During the lateral approach to the stifle, where is the stab incision in the stifle joint made to avoid damaging articular cartilage of the femoral condyle?
Into stifle joint at proximal end of incision
During the lateral approach to the stifle - One blade of a scissor is inserted into the joint and the scissor is advanced proximally, cutting? (3)
Joint capsule
Lateral parapatellar fibrocartilage
Fascia lata
During the lateral approach to the patella, we must ensure enough tissue is left on the LATERAL side of the joint capsule; for what reason?
Permit suturing
Lateral approach to the stifle; upon moving the patella medially; what should you do if this does not stay in place?
Extend the proximal end of the incision
After the movement of the patella medially on the lateral approach to the stifle; what exposes the cruciate ligaments and menisci?
Distal retraction of the fat pad.
After the lateral approach to the stifle - how is The joint capsule and lateral fascia of the stifle joint closed?
1 layer - continuous or interrupted.
Medial approach to the stifle:
Where is the skin incision?
A craniomedial incision is made and centred at the level of the patella.
The incision should start 5cm proximal to the patella and continue distally 5cm below the tibial crest.
On the medial approach to the stifle after the subcut tissue is incised - what is exposed?
parapatellar medial retinaculum
On the medial approach to the stifle - where is the joint capsule incised?
Medial ridge of paterllar tendon
On the medial approach to the stifle - where is the joint capsule incision continued to:
A) Proximally?
B) Distally?
A) Suprapatellar joint
B) Tibial tuberosity
What type of condition is Osteochondrosis?
Developmental
Define Osteochondrosis of the stifle
Osteochondrosis is a developmental condition of articular epiphyseal and physeal cartilage characterised by abnormal endochondral ossification.
WIth Osteochondrosis:
The cartilage lesion and possible exposure of the subchondral bone leads to what?
Synovitis
What about the joint leads to dysfunction and eventually 2ry OA with Osteochondrosis? (2)
Joint incongruity and misarticulation
What can Osteochondrosis progress to?
Osteochondritis dissecans
What is osteochondritis dissecans (OCD)?
Where the abnormal area of cartilage separates from the underlying bone as a flap.
In terms of the location found - how common is osteochondrosis to be in the stifle?
4th most common
Order these osteochondrosis locations in terms of the most common locations:
- Elbow
- Hock
- Shoulder
- Stifle
Shoulder
Elbow
Hock
Stifle
In the stifle, where are 96% of the osteochondrosis lesions found?
Lateral femoral condyle
Signalmen for stifle osteochondrosis:
- Sex
- Breed size
- Age
- Male
- Large/giant
- 5-9mo
Lameness with osteochondrosis can be minimal to severe but tends to have what onset?
Insidious (gradual)
What are common CE findings with osteochondrosis of the stifle? (3)
Joint effusion
Pain
Muscle atrophy
How can osteochondrosis be diagnosed?
Xrays (orthogonal)
Some cases - CT for additional detail
What are the radiographic signs of osterochondrosis of the stifle? (5)
Radiolucent defects of the subchondral bone of the condyle(s)
Sclerosis associated with the defect
Joint effusion
Intra-articular mineralised bodies
Secondary osteoarthritis
What is located on the lateral femoral condyle which can be confused for OCD lesion on xrays?
Extensor fossa
When is surgery recommended for OCD?
Regular re-examinations should be scheduled and if the clinical signs are not resolving or progressing then surgery should be recommended.
How can stifle OCD be approached surgically? (3)
Arthroscopy
Medial parapatellar arthrotomy
Lateral parapatellar arthrotomy
What does stifle OCD surgery consist of? (4)
Removal of the pathological cartilage (flaps, loose abnormal cartilage).
Debridement of subchondral bone bed to normal bleeding bone.
Micropicking (regular punctures/perforations at the site of the defect to a depth of 2-3mm created using a small gauge Kirshner wire or hypodermic needle) of the bone bed to stimulate bleeding and enhance fibrocartilage healing.
Joint lavage.
Following OCD surgery; exercise is restricted post op for 2 weeks. Then what?
gradually increased over the following 2-4 weeks.
What is the prognosis of stifle OCD after surgery - why?
Fair - poor
Loss of joint congruity, inferior biomechanics of reparative tissue and 2ry OA
Grafting of the lesions both by autogenous osteochondral grafts (OATS) or by synthetic grafts have been described with promising early results.
What complications maybe associated with grafting? (4)
- Morbidity
- Rejection
- Lameness
- OA
What are major stabilisers of the stifle and limit varus, valgus, rotational and translational instabilities?
The collateral ligaments
Where does the medial collateral:
A) From?
B) To?
From medial femoral condyle
To Proximedial tibia
Where does the LATERAL collateral ligament run:
A) From?
B) To?
A) From: Lateral femoral condyle
B) To: Lateral aspect fibular head
How can isolated tears of collateral ligaments occur?
Slips/falls
Athletic activity.
Define first degree sprain
Mild stretching causing minimal instability.
Define second degree sprain
Moderate stretching with some tearing of fibres causing moderate instability.
Define third degree sprain
Complete rupture or avulsion of the ligament with significant instability.
What does the degree of lameness depend on with ligament strain
Severity + duration of injury
How to test the lateral and medial collateral ligaments?
SEDATION to perform varus and valgus stress test
Why must you ensure the whole stifle is fully assessed with medial/lateral collateral ligament injuries?
Multiple stifle injuries more common
Why are xrays taken with collateral ligament ONLY injuries?
Avulsion #
What type of xrays can be taken to diagnose collateral ligament instability?
Stressed projections
Is 2nd degree sprain surgical or non surgical tx?
non
Is 1st degree sprain surgical or non surgical tx?
non
Is 3rd degree sprain surgical or non surgical tx?
Surgical
What is the non surgical management of 1-2 degree strain?
strict rest for three to four weeks before a gradual increase to normal over the following six weeks.
How can 3rd degree sprains be treated surgically? (4)
Ligament imbrication
Reduction and stabilisation of an avulsed fragment
Primary suture repair
Synthetic ligament replacement
How are synthetic ligament replacements placed?
screws or suture anchors placed at the origin and insertion with a figure of eight suture between them.
How is long term stability provided with synthetic ligament replacement?
Fibrosis
Following collateral ligament surgery what is the post operative plan? If followed - prognosis?
Following surgery strict rest followed by a rehabilitation programme delivered by a physiotherapist is likely to result in a good outcome.
Stifle luxation is a severe injury in dogs and cats, typically involving which three structures?
Cranial and/or caudal cruciate ligaments
Medial and/or lateral collateral ligaments (usually injured along with the joint capsule)
Medial and/or lateral meniscus
How common is stifle luxation?
Rare
What normally causes stifle luxation?
Major trauma e.g. RTA when the limb is weight bearing
What is found on CE with stifle luxation?(4)
A non-weight-bearing lameness is seen with stifle swelling, bruising and gross malalignment.
What needs to be assessed with stifle luxation? (2)
Nerves
and vessel
How do you assess the extent of damage with stifle luxation?
Under sedation/anaesthesia
What are you looking for with orthogonal xrays of a stifle luxation? (3)
- Avulsion #
- Concurrent injury
- Severity of displacement
What does surgery of patella luxation start with?
Thorough joint exploration to assess structures and severity damage
Following stifle luxations:
It can be difficult to repair or augment ligaments if..?
Cruciate ligaments and at least one of the collateral ligaments have ruptured
During stifle luxation surgery, how can joint alignment be optimised?
Temporary transarticular pin (removed at end of surgery)
When can a temporary transarticular external skeletal fixator can be placed during stifle luxation surgery?
After debridement of any mensicus injury and joint capsule repair
In stifle luxation surgery, what is used in small dogs and cats instead of an ESF?
Temporary transarticular pin
When should a transarticular external skeletal fixator or transarticular pin be removed following stifle luxation surgery?
After 6 weeks
What salvage procedure can be performed following stifle luxation, if the joint cannot be stabilised or if there is a neuro/vascular compromise? (2)
- Stifle arthrodesis
- Amputation
Prognosis with stifle derangement?
Severe injury, but prognosis is favorable with appropriate surgery
What long term complications are expected with stifle luxations? (3)
- Mild intermittent lameness
- Reduced stifle ROM
- 2ry OA
How common is patella ligament rupture?
Uncommon
What is patella ligament rupture a result of? (3)
- Laceration
- Blunt trauma
- Supraphysiological forces from the quadriceps muscle as may occur in a fall or athletic injury and iatrogenic trauma.
What concurrent fractures may be present alongside patella ligament rupture? (2)
- Patella #
- Tibial tuberosity #
What is expected on CE with patella ligament rupture? (3)
Lame
Swelling
Patella displacement
Patella ligament rupture:
The lameness is variable but is severe if there has been complete loss of what mechanism?
Quadriceps/patella ligament mechanism
Patella ligament rupture:
The patella will most likely be displaced A) (B) if the rupture is C) to the patella.
A) Proximally
B) Patella alta
C) Distal
Patella ligament rupture:
If the rupture is at the musculotendinous junction at the insertion of the quadriceps onto the patella then the patella may be displaced A) (B)
A) Distally
B) Patella baja
What diagnostics can be performed to diagnose patella ligament rupture? (2)
Radiography, especially when compared to the contralateral stifle, both in flection and extension, can confirm patellar displacement.
Ultrasound of the ligament can also help in diagnosis.
When can non surgical management be used for patella ligament sprains?
First and mild second degree sprain
When is surgery indicated for 1st and mild 2nd degree patella ligament sprains?
If non-surgical management fails or the initial injury was severe (e.g. complete rupture) then surgery is indicated.
What is involved in the non surgical management of patella ligament sprains? (4)
Strict rest for a minimum of three weeks
NSAIDs as required for analgesia
strict rest the exercise is gradually increased to normal over six to eight weeks.
Physiotherapy may aid the rehabilitation.
What surgical technique is used to restore functional length of patella ligament to aid in healing?
Repair of the ligament by suturing
What type of suture can be used for patella ligament repair? (3)
- Locking loop suture
- Pulley suture
- Modified double bunnel meyer
With patella ligament injuries; how can avulsion fractures of the tibial tuberosity be repaired?
Pins and tension band wire
How long does the patella ligament repair need to be protected for due to the forces during walk/trot?
4 weeks
Ideally 6-8 weeks
How can internal protection of patella ligament repair be performed?
Encircling loops of orthopaedic wire passed proximal to the patella and extending to the tibial tuberosity or the musculotendinous junction to the tibial tuberosity.
Will a cast or splint be beneficial following surgical repair of the patella ligament?
Protection with a cast or splint can be attempted but it is very difficult to adequately immobilise the stifle using such a technique.
What external immobilisation method can be used following patella ligament repair?
Transarticular external skeletal fixators
Following patella ligament repair - what is the morbidity of Transarticular external skeletal fixators why?
These are associated with significant morbidity given that the transfixation pins travel through deep muscles
What phase do Transarticular external skeletal fixators provide significant protection?
Early healing
What type of external fixator following patella ligament sx allows controlled motion of the stifle?
Hinged external fixator
What is the prognosis following patella ligament repair if the primary repair is adequate?
Good
Why is the patella ligament at risk of reinjury?
healing will be slow and original tissue strength is never achieved
The femoral trochlea, articulates with?
the patella.
