Short Notes in Orthopaedics

 An old woman falls inside a bathroom as her feet slipped off. Her X-ray is shown as below. https://kwaktalk.org/ortho/2020/12/27/hip-fractures What should we know about her ?          When did it happen      Other injuries     Closed or Open fracture     Past Medical History- any medications is she taking , drug allergies, any other co-illnesses including                                                      mental health     Initial Management           Analgesia          Plain radiographs          Admission          Routine blood investigations , ECG          Rehydration          Plan for surgery withi...

 Somebody with a history of fall from height or jumping ,sustain this fracture.   Important objective Parameters to look for in X-ray     Bohler's angle and Gissane's angle - Both are reduced.     Reduction in Bohler's angle (N- 25-40 degrees) is suggestive of posterior facet involvement.      https://www.ebmconsult.com/articles/critical-angle-gissane-calcaneus-fractures https://www.orthobullets.com/trauma/1051/calcaneus-fractures Management in ER      ATLS Review     R/o associated injuries     R/o open wounds, compartment syndrome of foot     Document NV status of foot     Elevate        Analgesia      What are further investigations you would like to see ?     Broden's view - to visualize anterior surface of posterior foot     AP of foot to see C-C joint     CT -scan - understand fracture configuration    ...

  Lisfranc Joint consists of three cuneiform and two cuboid metatarsal articulations.    Stability - strong ligament and recessing of second metatarsal head.                      Lisfranc ligament - base of 2nd metatarsal to medial cuneiforms.  How to proceed to this type of injuries ?     Always a trauma case management quires ATLS approach,   Analgesia   Elevation   Resting/ Splinting   Rule out Compartment Syndrome    Radiographs - AP  / Oblique      If needed CT      wait swelling to subside (skin softening , wrinkles ) What we see on X-ray ?     AP view - 2nd MT and medial cuneiform medial borders align     Oblique - medial border of 4th MT and cuboid align.                         fleck sign - avulsion of Lisfranc ligament.  http...

https://litfl.com/hawkins-classification/ Hawkins's  Classification      I - Talar Neck Fracture       II - Talar Neck Fracture with Subtalar Dislocation     III - Talar Neck Fracture with Subtalar and Tibiotalar Dislocation     IV - Talar Neck Fracture with Subtalar , Tibiotalar and Talonavicular  Dislocation      What other information would you like to know ?     status of patients , high velocity injury     other injuries     open or closed fracture     NV status of foot     X-ray foot/ankle and CT scan if available What is the standard treatment ?     Reduction and fixation with cannulated compression screws.     AM approach - for neck of talus                                      to openly reduce and fix fracture from an...

         Open Fractures of Tibia Diaphysis  (Daniel N. Segina, Robert V. Cantus, David Templeman ) How do you manage such a case ?     ATLS review. R/o life threatening and more urgent issues.     Examine wound, photograph it, cover it with a saline soaked gauze.     Analgesia     Splinting          Antibiotics     Tetanus Toxoid     Obtain AP and Lateral radigraphs     transfer to theatre      Initial wash /scrub for gross contamination     Thorough debridement of skin, fat, fascia, muscle, bone            Fracture stabilization before further wash out.     Dressing, splint leg with physical examination          make a plan for further management.      continue ex-fixator or remove the ex-fixator ,      back slab and convert to IMIL after f...

 MRI construction - comprises of four parts.          Electromagnet -superconducting coils          RF System coils          Gradient Coils          and Computer system             How it works ?          Protons align with magnetic field in MRI scanner.    

 What kind of data are available in orthopaedics ?    1.Non-continuous, qualitative or categorical. Gu 1, 2, 3 -Analysed using Chi-squared or Fischer's exact test      2.Continuous or variable data e.g. height, age, knee valgus angle     These data are often not always -Gaussian distribution e.g. symmetrical bell-shaped curve.     Continuous data described using Mean, Median and Mode.     With Normal distribution, mean/median and mode are equal. What is dispersion ?     It is a variability of a data set.If all values are zero, dispersion is zero.     Measured using Quartiles, SD and Variance.     Variance- how much it deviates from mean.     SD- square root of variance (to give same original dimension as data )     Standard error of mean (SEM) - measures how closely sample mean of data set approximates to                   ...

  Hypothesis       Proposition that serves as a starting point for further investigation.    Null Hypothesis     Assumption that any differences between groups in your study occurred purely by a chance.     How to set a clinical trial ?     Identify a problem.     Ask a scientific question - define null hypothesis to test.       Design a study.               define population               methodology of study               power analysis               define outcome measures       Ethical approval       Register trial and conduct        Recruit patient         Analyze results         Interpret the findings. Type I error or alpha err...

 Screw parts      https://www.slideshare.net/ssusere6b07d/screws-in-orthopaedic-surgerypptx     1. Head - hexagonal - increased torque with maximum contact - provides attachment for screwdriver     2. Counter sink -                run out between head/shaft and thread.     3. Shaft                inner core diameter     4. Thread outer diameter is directly proportionate to pull out strength.               80 % grip - near cortex                20 % grip from far cortex.     5. Crest/root of thread     6. Pitch (lead )-distance advanced for one 360 degrees turn (cancellous >cortical > locking).     7. Flutes -removes debris     8. Tip - cortical -blunt                ...

Stress-strain curve       https://byjus.com/jee/modulus-of-elasticity/ Zone 1 - Area of Elasticity Young's modulus           Stress/Strain in elastic zone.          Measures stiffness of material.          Higher the Young's modulus, steeper the slope + higher the stiffness.  what happens after proportional limit ?          after this material elongates. what is ultimate strength ?          it is the point of maximum stress. Stress gradually reduces as strain increases. what happens after fracture point?          material fails. Area under the curve is energy of failure. what is plastic zone ?          material does not regain its original length when load applied.           

 Potential areas of lucency around femoral and acetabular components of THR according to Gruen (femur ) and De-Lee and Charnley (cup).                         Ortho PG notes Pathological process of aseptic loosening           Osteoclastic bone resorption at bone cement interface.          Polyethylene wear debris at bearing surfaces combined with cement debris formed from movement at            interfaces.            In vitro, activated macrophages is the key. Macrophage after phagocytosis ,response in two ways.               a. secretion of TNF-alpha ,IL-1,IL-6,PGE2               b. activated macrophages differentiate into osteoclasts via distinct pathways (RANKL activated              ...

                      Bone cement  Component - Powder - Pre-polymerized PMMA                                                Barium Sulphate (opacifier)                         Liquid-       Mono Methyl-metha-acrylate (MMA Monomer )                                                 N-dimethyl-p-toludine, which acts as an accelerator (accelerator )                                                  Hydroquinone , which acts...

  https://www.nashvillejointreplacement.com/hip-implants Metal on Metal e.g. Cobalt Chromium  Advantages over a conventional bearing surface      1. large wear ; linear wear rate of < 0.01 mm/year compared with metal on poly UHMWPE bearings with a wear rate of 0.1-0.2 mm/year.     2. Hydrodynamic lubrication -capable of fluid film lubrication                                                                  - likely that boundary lubrication occurs when hip at rest and fluid film                                                                       ...

 Mention type of Cemented Stem Designs  1. Charnley stem Design 2. Exeter Stem Design https://holycrossleonecenter.com/exeter-hip-stem-still-gold-standard-industry Write Characteristics of Exeter system.      Exeter is polished, double tapered stem. What is the design philosophy of Exeter stem  ?          Taper slip (force close ) principle               Stability - achieved by allowing micromotion at prosthesis-cement mantle           Collarless geometry , polished surface finish (< 0.01 Pa )          Polish surface - allow tapered stems subside within cement mantle ,generate radial stress at bone cement and prosthesis interface in turn stabilizing bone cement prosthesis composite.      viscoelastic property of cement (creep and stress relaxation ) are key factors in this process. How do they fail ?   ...

 https://hipandkneebook.com/new-blog/2017/3/13/tha-implants-history-of-tha Charnley Stem      Composite Beam Design      Collar /flange and a rough surface finish      Composite Beam or Shape close design      - relies on friction to maintain position of stem within cement mantle      - rough surface finish ( > 2 Ra ) collar / flange intended to minimized micromotion at prosthesis cement         interface.  How does this fail ?           Composite beam designs fail mechanism-          Due to movement at prosthesis cement interface,          Rough surface abrades cement mantle, once  micro-movement is established.          Gap formation in turn leads to increased micro movement and circulation of wear debris.               ...

    Picture of Roentgen Stereophotogrammetric Analysis (RSA) (https://www.researchgate.net/figure/Radiostereometric-analysis-RSA-images-with-computer-aided-design-CAD-model-during_fig1_353956389) How it works ? With two D X-ray images , determines 3 D co-ordinates of an object within the calibration cage from two 2 D X-ray image.  uses      measures migration over time of joint replacements or the implant stabilized in one point. 

    TKR COMPONENTS WOTH UHMWPE Tibial           Insert UHMW Polyethylene - Long hydrocarbon chain held together by covalent bonds.  Exists in two forms -           1. Disorganized amorphous phase          2. More organized crystalline phase How is this material manufactured ?    Zeigler Process      1.Ethylene gas polymerized at a low temperature, low pressure environment catalyst Titanium Chloride          produces a fine UHMWPE powder.     2. Then the powder processed in one of the following methods-               - Ram extrusion produces bar stock, lowest quality               - sheet compression moulding -higher quality                - Direct compression moulding - expensive shape of fin...