RADIOGRAPHIC ANATOMY OF KNEE JOINT AND ITS RADIOGRAPHIC VIEWS.pptx

Radiographic anatomy of knee joint

1. RADIOGRAPHIC ANATOMY OF KNEE JOINT AND ITS RADIOGRAPHIC VIEWS PRESENTATION BY : DR MIRZA SANAULLA MODERATOR : DR RAGHURAM P

2. OVERVIEW KNEE JOINT INTRODUCTION GROSS ANATOMY OF KNEE JOINT RADIOLOGICAL ANATOMY OF KNEE JOINT NORMAL VARIANTS RADIOLOGICAL VIEWS OF KNEE JOINT

3. KNEE JOINT Largest joint in human body Modified hinge joint – synovial joint type It incorporates two condylar joints between the condyles of femur and tibia,and one saddle joint between femur and patella. Flexion and extension of the leg as well as some rotation in the flexed position.

4. Patellofemoral Joint The patellofemoral compartment is a saddle joint between the femoral trochlea and patella, formed by a large steeper lateral facet, resisting patellar lateral displacement, and two smaller medial facets.

5. Ligaments of knee joint

6. Bursae of knee joint

7. FATS PADS Infrapatellar fat pad (of HOFFA) Anterior supr apatellar fat pad Posterior su prapatellar ( pre-femoral fat pad) Posterior fat pad

8. X-rays of knee joint AP VIEW

9. LATERAL VIEW

10. KNEE LATERAL –HORIZONTAL BEAM

11. KNEE LATERAL –HORIZONTAL BEAM

12. NORMAL VARIANTS : BIPARTITE PATELLA 1-3 ossification centres appear at 3 years and fuse at puberty . These may give rise to an irregular appearance of the normal unfused patella. A bipartite(or multipartite) patella is a common variant when the superolateral corner fails to fuse. The  Saupe  classification describes the bipartite patella according to the location of the secondary ossification center : type I : inferior pole ~1% type II : lateral margin ~20-25% type III : superolateral portion ~75% 

13. BIPARTITE PATELLA

14. FABELLA The fabella is a sesamoid bone frequently found in the lateral head of gastrocnemius.

15. RADIOGRAPHIC VIEWS BASIC PROJECTIONS: ANTERO-POSTERIOR(SUPINE) LATERAL ADDITIONAL PROJECTIONS : 1.LATERAL –HORIZONTAL BEAM 2.ANTERO-POSTERIOR STANDING 3.STRESS PROJECTIONS-AP 4.POSTERO-ANTERIOR (PATELLA) 5.SKYLINE PROJECTION 6.INTERCONDYLAR NOTCH (TUNNEL)

16. ANTERO-POSTERIOR VIEW (SUPINE) Direction and location of the X-ray beam • The vertical collimated central beam is centred 1 cm below the apex of the patella through the joint space, with the central ray at 90° to the long axis of the tibia (midway between the palpable upper borders of the tibial condyles )

17. AP VIEW (SUPINE) Essential image characteristics • The patella must be centralised over the femur. • The image should include the proximal 1/3 of the tibia and fibula and distal 1/3 of the femur.

18. LATERAL VIEW Direction and centring of the X-ray beam • Centre to the middle of the superior border of the medial tibial condyle, with the central ray at 90 degrees to the long axis of the tibia .

19. Essential image characteristics • The patella should be projected clear of the femur. • The femoral condyles should be superimposed. • The proximal tibio -fibular joint is not clearly visible.

20. Insall-Salvati ratio The  Insall-Salvati ratio or index is the ratio of the patella tendon length to the length of the   patella and is used to On plain radiographs: Patella baja : <0.8 Normal : 0.8-1.2 patella alta :  >1.2 

21. ANTERO-POSTERIOR (STANDING) This projection is useful to demonstrate alignment of the femur and tibia in the investigation of valgus or varus deformity. Any such deformity will be accentuated when weight bearing . Direction and location of the X-ray beam The collimated horizontal beam is centred 1 cm below the apex of the patella through the joint space, with the central ray at 90° to the long axis of the tibia (midway between the palpable upper borders of the tibial condyles ).

22. AP VIEW STANDING

23. To enable correct assessment of the joint space, the central ray must be at 90° to the long axis of the tibia and, if necessary, angled slightly cranially. If the central ray is not perpendicular to the long axis of the tibia, then the anterior and posterior margins of the tibial plateau will be separated widely and assessment of the true width of the joint space will be difficult . In the AP projection, the patella is remote from the receptor. Although the relationship of the patella to the surround ng structures can be assessed, the trabecular pattern of the femur is superimposed. Therefore, this projection is not ideal for demonstrating discrete patella bony abnormalities.

24. LATERAL –HORIZONTAL BEAM (TRAUMA) This projection replaces the conventional lateral in all cases of gross injury and suspected fracture of the patella Direction and location of the X-ray beam • The collimated horizontal beam is centred to the upper border of the lateral tibial condyle , at 90° to the long axis of the tibia. The femoral condyles should be superimposed and the soft tissues adequately demonstrated to visualise any fluid levels within the supra-patella pouch.

25. LIPOHAEMARTHROSIS

26. Stress projections for subluxation Stress projections of the knee joint are taken to show subluxation due to rupture of the collateral ligaments . Stress is applied to the joint by medical personnel .

27. ANTERO-POSTERIOR STRESS PROJECTION Position of patient and cassette • The patient and cassette are positioned for the routine anteroposterior projection. • The doctor forcibly abducts or adducts the knee, without rotating the leg . Direction and centring of the X-ray beam • Centre midway between the upper borders of the tibial condyles, with the central ray at 90 degrees to the long axis of the tibia.

28. POSTERIO-ANTERIOR -PATELLA Position of patient and cassette • The patient lies prone on the table, with the knee slightly flexed. • The centre of the cassette is level with the crease of the knee. Direction and centring of the X-ray beam • Centre midway between the upper borders of the tibial condyles at the level of the crease of the knee, with the central ray at 90 degrees to the long axis of the tibia. Notes • The beam may have to be angled caudally to be at right angles to the long axis of the tibia. • The patella may be demonstrated more clearly as it is now adjacent to the image receptor and not distant from it, as in the conventional antero-posterior projection.

29. POSTERO-ANTERIOR VIEW

30. SKYLINE PROJECTION The skyline projection can be used to: • assess the retro-patellar joint space for degenerative disease; • determine the degree of any lateral subluxation of the patella with ligament laxity; • diagnose chondromalacia patellae; • confirm the presence of a vertical patella fracture in acute trauma . The optimum retro-patellar joint spacing occurs when the knee is flexed approximately 30–45 degrees . Further flexion pulls the patella into the intercondylar notch, reducing the joint spacing; as flexion increases, the patella tracks over the lateral femoral condyle. The patella moves a distance of 2 cm from full extension to full flexion.

31. Supero -inferior view This projection has the advantage that the radiation beam is not directed towards the gonads . Position of patient and cassette • The patient sits on the X-ray table, with the affected knee flexed over the side . Direction and centring of the X-ray beam • The vertical beam is directed to the posterior aspect of the proximal border of the patella. The central ray should be parallel to the long axis of the patella.

32. SKYLINE VIEW –SUPERO INFERIOR NORMAL SKYLINE VIEW REDUCED FLEXION –CAUSING TIBIA PROJECTION OVER PATELLA INCREASED FLEXION –APPEARS AS LATERAL SUBLUXATION

33. I nfero -superior Projection Position of patient and cassette • The patient sits on the X-ray table, with the knee flexed 30–45 degrees and supported on a pad placed below the knee . Direction and centring of the X-ray beam • The tube is lowered. Avoiding the feet, the central ray is directed cranially 5- 10 degrees to pass through the apex of the patella parallel to the long axis.

34. Infero -superior – patient prone This projection has the advantage in that the primary beam is not directed towards the gonads, as is the case with the infero -superior projection. However, the patient has to be able to adopt the prone position, which may not be suitable for all patients . Position of patient and cassette • The patient lies prone on the X-ray table, with the cassette placed under the knee joint and the knee flexed through 90 degrees . Direction and centring of the X-ray beam • Centre behind the patella, with the vertical central ray angled approximately 15 degrees towards the knee, avoiding the toes

35. INTERCONDYLAR VIEW -TUNNEL VIEW This projection is taken to demonstrate loose bodies within the knee joint or to demonstrate fractures of the tibial spines. Position of patient and cassette • The patient is either supine or seated on the X-ray table, with the affected knee flexed to approximately 60 degrees.

36. Direction and centring of the X-ray beam • Centre immediately below the apex of the patella, with the following angulations to demonstrate either the anterior or posterior aspects of the notch : Angulation to the long Anatomy demonstrated axis of the tibia 110 degrees : Anterior aspect of the notch 90 degrees : Posterior aspect of the notch

37. INTERCONDYLAR NOTCH (TUNNEL) AP VIEW

38. Intercondylar notch (tunnel) – posterior–anterior (racing start) The advantage of this method is the reduction in magnification and increased resolution The affected lower leg is extended with the tibia parallel to the tabletop and the patient is asked to lean forwards, mov i ng the femur into an angle of 50° from the tabletop Direction and location of the X-ray beam • The collimated vertical beam is centred to the middle of the knee joint/ popliteal fossa (approximately over the skin crease posterior to the joint

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