Adult recon Flashcards
AVN Femur
Osteonecrosis is a condition with debilitating results that can cause a structural collapse in the joints affected
Direct Risk Factors
Trauma:
- fracture or dislocation
- Sickle cell disease
- HIV infection
- Chemotherapy
- Radiation
- Myeloproliferative disorders
- Gaucher disease
Indirect Risk Factors
- Corticosteroids
- Alcohol abuse
- Tobacco use
- Systemic lupus erythematosus
- Organ transplantation
- Renal failure
- Coagulation abnormalities
- Pregnancy
- Genetic factors
- Caisson disease
AVN
Intravascular
- Extraosseous arterial factors
- Intraosseous arterial factors
- Intraosseous venous factors
Extravascular
- Intraosseous extravascular factors
- Extraosseus extravascular (capsular) factors
Pathophysiology
- Intraosseous hypertension theory
- Abnormality of extraosseous blood flow
- A fat emboli
- Clotting abnormalities such as deficiencies in protein S, protein C and antithrombin III in patients with ON
AVN
- Silent Preclinical and pre-radiographic Bone marrow pressure studies abnormal and core biopsy would reveal characteristic histological patterns. This stage was not described in original classification. No clinical symptoms. Normal radiographs. MRI non-diagnostic
- Preradiographic Radiographs usually normal or at most minor changes such as subtle loss clarity with poor definition or blurring of trabeculae pattern. Diagnosed with a positive MRI or bone scan. Earliest clinical manifestation of the syndrome. Usually presents with sudden onset of ischaemic hip pain in the groin with or without radiation down the front of the thigh
- 2A Precollapse (Before flattening of head or This extends over several months with clinical symptoms and signs persisting or sequestrum formation worsening. Radiographs demonstrate osteopenia/sclerosis femoral head
- 2B Crescent sign Curvilinear subchondral radiolucent line due to subchondral fracture
- 3 Collapse Segmental flattening and collapsed femoral head. Worsening pain, limp, limited range of Bone sequestrum broken off motion in all planes
- 4 Osteoarthritis Terminal phase, secondary degenerative change superimposed on a deformed femoral head
Avn
- 0 Normal x-ray, bone scan and MRI, diagnosed on histology
- I Normal x-ray, abnormal bone scan or MRI findings (minimal pain)
- II Sclerosis and/or cyst formation in the femoral head
- III Subchondral collapse (crescent sign) without flattening
- IV Flattening of the femoral head without joint narrowing or acetabular involvement
- V Flattening of the femoral head with joint narrowing and/or acetabular involvement
- VI Advanced degenerative change
Outerbridge arthroscopic grading system
- Grade 0 Normal cartilage
- Grade I Softening and swelling
- Grade II Partial thickness defect, fissures 1.5 cm diameter
- Grade III Fissures down to subchondral bone, diameter > 1.5 cm
- Grade IV Exposed subchondral bone
ICRS system
- Normal Grade 0 Almost normal Grade 1a – Superficial lesions/softening Grade 1b – As 1a and/or superficial fissures and cracks Abnormal Grade 2 – Extent < 0% of thickness Severe lesion Grade 3a – Extent >50% of thickness Grade 3b – Down to the calcified layer Grade 3c – Down to subchondral bone (without penetrating) Grade 3d – Includes bulging of the cartilage around the lesion Very severe lesion Grade 4a – Penetration of subchondral bone but not across the entire diameter of the defect Grade 4b – Penetration across the full diameter of the defect
Osteochondritis dissecans (OCD)
A lesion of subchondral bone that results in subchondral delamination and sequestration with or without articular mantle involvement (Stanitski)
Osteochondritis dissecans (OCD)
A lesion of subchondral bone that results in subchondral delamination and sequestration with or without articular mantle involvement (Stanitski)
Pappas classification (according to age at detection)
- Category I: Below age 12 (excellent prognosis)
- Category II: Between 12 and 20 years
- CategoryIII: Above 20 years
McDaniel – Rule of thirds
Patients with ACL-deficient knee One-third are able to compensate and can pursue normal recreational sports One-third are able to compensate but will have to reduce their sporting activities One-third do poorly and develop instability with simple activities of daily living However, a few are able to compensate and pursue normal recreational sports and most patients try to keep their activities within ‘the envelope of stability’ to avoid recurrent giveaways21,22
Hamstring Graft
Hamstring graft autograft This graft is usually quadrupled. Advantages: Patient’s own tissue Small incision Large cross-sectional area of tendon Relatively easy passage of graft Less donor site morbidity Disadvantages: Slow tendon-to-bone healing in the tunnel in 8–12 weeks No bone graft in the tunnels – ‘windshield wiper’ effect (can occur with the use of suspensory fixation which can lead to tunnel abrasion and expansion when the knee is in motion) Deep flexion weakness after surgery Possibility of injury to saphenous nerve (poor technique)
ACL Ideal fixation is strong enough to avoid failure stiff enough to restore knee stability by resisting displacement under load Secure enough to avoid slippage of the graft from its initial position. It is preferable for the fixation to be biocompatible, MRI safe and allow for easy revision.
Aperture fixation: Interference screw at the level of the joint (metal or bioabsorbable). Note that these screws interfere with the 360° circumferential healing of the graft in the tunnel Suspensory fixation Cortical: EndoButton , tightrope, screw posts, staples Cancellous: transfixion pin/cross-pin WasherLoc (tibia) None (Press-fit)
Principles of ACL reconstruction Graft: Best to use a biologically active graft Tunnels: ‘anatomically’ and isometrically placed tunnels. Exact tunnel position is controversial with no consensus yet in the orthopaedic literature or the knee community Fixation: The graft should be adequately tensioned Rehabilitation should respect fixation choice
Femoral tunnel placement the optimum tunnel position in anatomic single bundle ACL reconstruction remains controversial: Recent evidence suggests that placing the femoral tunnel through the anatomic centre of the femoral origin of ACL may further improve the rotatory stability compared to antromedial bundle femoral tunnel position24 Tibial tunnel: the tibial tunnel aperture should be anterior to the PCL and within the footprint of the ACL. It is usually between the medial tibial spine and the anterior horn of the lateral meniscus. The trajectory of the tunnel should be less the 75° To tension the graft appropriately, it is common practice to apply 40 N or 10 lb of tension on the graft while it is secured in 20–30° of flexion
Tunnel placement technical errors Anterior placement of the femoral tunnel limits flexion Anterior placement of the tibial tunnel limits extension
Tunnel widening – Secondary to graft motion within the tunnel (both biological and mechanical factors) and found more with non-aperture fixation methods. More than 3 mm of motion interferes with graft incorporation within the tunnel Three types of graft motion 1. Bungee cord effect – Longitudinal motion 2. Wind-wiper effect – Horizontal motion 3. Creep of the graft – This leads to tissue elongation Cyclops lesion from the residual tissue anterior to the ACL which blocks extension. Some surgeons prefer tunnelling the graft into the native ACL stump at its tibial attachment
ODEP - Orthopaedic data evaluation panel
- 10 ten years of evidence full compliance with NICE benchmark.
- The letter represents the strength of evidence (data) presented by the manufacturer.
- A strong evidence generally higher numbers of patients (giving greater confidence in the results presented), with all patients being subject to followup (their outcomes recorded).
- The star has been added to the rating system following revised guidelines from NICE in February 2014, in which a benchmark replacement rate of less than 1 in 20 (5%) at 10 years was defined.
- The star is awarded where products are evidenced to comply with this benchmark
Metals
Stainless steel
- Iron 62%
- Chromium- 18%
- molybdinum 3%
- Nickle 16%
- carbon 0.03%
Cobalt chrome
- Cobalt 34-64%
- Chrome 20-30%
- Molybdinum - 6-10%
- Nickle 2.5- 35%
- carbon 0.02 - 3.5%
Titanium
- Titanium 89%
- AL 6%
- Vanadium 4%
- Others 1%
MOM hip
Reverse shoulder arthroplasty
( paul Gemmonnt 1987)
- intrinsic prosthetic stability.
- Concavity of the supporting part and convexity of the weight bearing part (glenoid).
- Glenosphere centre at or within the glenoid neck
- Medialised and distalised centre of rotation.
- In the reverse shoulder design the risk of dislocation is reduced as the humeral concave component is larger and deeper than in TSA and it articulates with a large hemispheric ball.
PJI
