cos jan 2025

A 75 years old patient presents with the painful right total hip replacement that was performed 2 years ago and as always remained painful. Blood tests and a joint aspirate was performed. Select the minimum criteria for diagnosis of a periprosthetic joint infection in this scenario.

• A. Synovial WBC count > 3000 cells/ μl, with both ESR and CRP elevated

• B. Synovial WBC count > 10000 cells/ μl, with both ESR and CRP elevated

• C. Synovial WBC count > 15000 cells/μl, with both ESR and CRP elevate15

• D. Synovial WBC count > 15000 cells/μl, with either ESR and CRP elevated

Answer explanation

A 78 years old male sustained a fall after two years of THR. What is the type of this fracture and the management?

• A. Vancouver type B2 and stem revision

• B. Vancouver type B2 and ORIF

• C. Vancouver type B3

  and stem revision

• D. Vancouver type B3

  and ORIF

Answer explanation

Eighty-one Vancouver B2 periprosthetic femoral fractures, treated between 2010 and 2019,

Revision did not exhibit better radiological results;

Internal fixation resulted in significantly less perioperative blood loss and a shorter operating time

ORIF is a viable alternative to revision arthroplasty,particularly in older patients.

Identify this person and his contribution to orthopedics

• A. Kulzer - Patented the mechanism for polymerizing PMMA at room temperature 

• B. Themistokles Gluck - Used a plaster and colophony cement to fix a total knee prosthesis made of ivory

• C. Otto Röhm -Developed PMMA

• D. Degussa- Patented the mechanism for polymerizing PMMA at room temperature 

Which of the following statement is false?

• A.1985: The Unimation Puma 200, an industrial robot, was used in a brain biopsy

• B. 1992: The ROBODOC system was used for total hip replacements

• C. 1987 - NeuroMate® is one of the oldest running systems commercially available to perform variousneurological procedure

• D. 1987 - The CASPAR system was the first used for total hip replacement

Answer explanation

The CASPAR system was used in 1997 for TKA, THR and ACL repair

When cementing a femoral stem as per current thinking, what is the most likely cause for severe hypotension related to " bone cement implantation syndrome"?

• A. Anaphylaxis to PMMA molecules

• B. Multiple emboli

• C. Metabolites of the monomer entering the circulation and vasodilatation

• D. Exothermic effect

Which of the following is not an expected finding in THR in Paget's disease?

• A. Valgus femoral neck

• B. Acetabular protrusion

• C. More blood loss

• D. High cardiac output

An 80 years old pt C/O groin pain of 18 months following THR. O/E pain reproduced with resisted hip flexion. No E/O in infection in blood workup. Radiographs are normal apart from a retroverted cup. The most appropriate next step is

• A. Triphasic bone scan

• B. Steroid injection into Iliopsaoas bursa

• C. Aspiration of hip joint

• D. Proceed to cup revision

Answer explanation

•- 4.3% of THR - iliopsoas impingement

•- most common site is anterior rim of acetabulum

•- extrusion of cement, prominent acetabular component or retroverted cup

•- to be considered when, pain in groin during active hip flexion like climbing upstairs, getting in and out of car

Which Artery is most likely to cause uncontrollable bleeding in posterior approach to hip

• A. inferior gluteal

• B. superior gluteal

• C. Ascending br of Lat circumflex Femporal A

• D. Pudental

Answer explanation

Inferior gluteal artery if injured retract into pelvis , may require to change to supine position and laparotomy to control bleeding.

9. 9. Regarding Freeman-Swanson bi-compartmental knee prosthesis the true statement is

• A. First bicompartmental knee arthroplasty without a hinge for stabilization was the Polycentric Knee

• B. Medial and lateral tibial compartments were resurfaced separately

• C. First bicompartmental knee arthroplasty using a hinge with intramedullary stems.

• D. SAV Swanson was a Professor of Mechanical Engineering

Answer explanation

• - Freeman-Swanson bi-compartmental knee prosthesis -truly the first iteration of the current TKA, in both theory and design

• - emphasize mechanical stability and prioritize function over preservation of anatomy

• - Introduced the idea of creating parallel cuts perpendicular to the mechanical axis.  He introduced intramedullary guides for this.  

• - spacer blocks for gap balancing.  Laminar spreaders were first used

• - The femoral component was made of cobalt-chrome. The tibial component was made of polyethylene. And there was just one implant size!

10. 10. A 75 years old patient with long standing painful TKR. According to the international consensus meeting ( ICM) for periprosthetic joint infection, which criterion if present alone is considered diagnostic of periprosthetic infection?

• A. Positive histology analysis of periprosthetic tissue

• B. Raised ESR & CRP

• C. Raised synovial WBC count or ++ change on leucocyte esterase test strip

• D. Two positive periprosthetic culture with phenotypically identical organisms

Answer explanation