Hemiarthroplasty

Basic of hemiarthoplasty

1. HEMIARTHROPLASTY DR ANSHUL SETHI PG ORTHOPAEDICS

2. Overview INTRODUCTION HISTORY INDICATIONS OF HEMIARTHROPLASTY TYPES OF PROSTHESIS STEM PROSTHESIS MEDULLARY PROSTHESIS BONE CEMENT BASIC TERMS PREOPERATIVE PLANNING TEMPLATING VARIOUS APPROACHES CASE DISCUSSION EXAMINATION PRE OP XRAY APPROACH USED POST OP XRAY POSSIBLE COMPLICATIONS POST OP REHABILITATION

3. INTRODUCTION HEMIARTHROPLASTY MEANS REPLACEMENT OF HALF JOINT. It involves replacement of femoral head with prosthesis while retaining the natural acetabulum ( endoprosthesis )

4. HISTORY Prosthesis replacement was introduced in 1932 by Grooves by replacement of femoral head with IVORY In 1938 smith person first used Vitallium mould arthroplasty for hip in case of ankylosis . In 1947 bipolar prosthesis first introduced by james E. bateman and gilbert In 1983 Charnley –Hastings used bipolar prosthesis

5. INDICATIONS Fracture neck of femur is the commonest cause in old age individual Inflammatory arthritis Rheumatoid Juvenile idiopathic Ankylosing spondylitis Osteoarthritis (degenerative joint disease, hypotrophic arthritis) Primary Secondary Developmental dysplasia of hip Coxa plana (Legg- Calvé - Perthes disease) Posttraumatic Slipped capital femoral epiphysis Paget disease Osteonecrosis

6. Types of prosthesis STEM PROSTHESIS MEDULLARY PROSTHESIS

7. STEM PROSTHESIS It has head and a stem Stem is inserted into the neck and anchored in the cortex of the shaft Not used nowdays Eg : JUDGET BROTHERS

8. MEDULLARY PROSTHESIS It has a head and stem Anchored in medullary canal It Is either fixed by Press fit or by bone cement Austin moore 1957 devised intramedullary self locking prosthesis with fenestration to facilitate bone growth and to increase blood supply

9. UNIPOLAR PROSTHESIS HEAD : It range from size 39mm to 59mm Neck Stem : triangular in shape , thin and become easy for insertion but chances of breakage of tip is there Collar Fenestrations : it help in increasing bone growth in between prosthesis to allow better fixation and increase vascular growth

10. Types of unipolar prosthesis Austin moore prosthesis Thompsons prosthesis

11. BIPOLAR PROSTHESIS Gilberty and baetman in 1974 used bipolar prosthesis. Erosion and protrusion of acetabulum would be less because of motion present between metal head and inner bearing Motion between metallic cup and acetabulum as cup is not fixed

12. Bipolar designs provide greater overall range of motion than unipolar designs or convential THR It is done with head size ranging from 22mm or 32mm diameter

13. ADVANTAGES WIDE RANGE OF MOTION BETTER STABILITY INCREASED LIFE SPAN OF PROSTHESIS CAN CONVERT INTO TOTAL HIP ARTHROPLASTY LATER LESS WEAR AND TEAR OF THE THE FEMORAL HEAD DUE TO LESS FRICTION

14. WIDE RANGE OF MOTION Due to size and geometry of inner bearing After certain arc of abduction-adduction movements and then further movement take place between acetabulium and outer metallic cup prosthesis

15. Better stability At the degree of movement of the inner bearing , joint tends to dislocate which is prevented by movement of outer bearing that too in opposite direction

16. UNIPOLAR VS BIPOLAR PROSTHESIS UNIPOLAR LOWER COST SIMPLE TO PERFORM BIPOLAR LESS WEAR MORE MODULAR MORE EXPENSIVE CAN CONVERT INTO THR

17. CEMENTED VS PRESS FIT STEM CE MENTED STEM Acrylic cement is now standard for femoral stem fixation. Improved mobility , function and walking aids less chance of peri -prosthetic fracture. Sudden intra-op cardiac death risk slightly increased due to addition of additional cement material ( methamethacrylate embolism chances is higher ) NON CEMENTED (PRESS-FIT) 2 pre- requsite Immediate mechanical stability at the time of surgery Good contact between implant surface and the viable host bone. Complain of pain is common Implant selection should be more precise Chances of loosening of stem is higher Intra-operative fracture of shaft of femur is more

18. BONE CEMENT POLYMETHYLACRYLATE remains one of the most enduring materials in orthopaedic surgery. In ARTHROPLASTY : bone cement allows swcure fixation of implant to bone It’s not a glue , it act as grout (fixation is achieved with ingrediants not with adhesion) It act as mechanical interlock and space filling

19. COMPOSITION OF BONE CEMENT

20. PHASES OF BONE CEMENT DIFFERENT PHASES OF BONE CEMENT ARE : 1 . MIXING PHASE : (UPTO 1 MIN) Wetting and polymerization ; cement relatively liquid ; very moveable ; at the end mixture is homogenous sticky mass. WAITING PHASE : (VARIABLE UPTO SEVERAL MINUTES ) Chain propogation ; cement less liquid ; more chains ; less movable ; cement is neither sticky nor tough. WORKING PHASE : ( 2-4 months ) chain propogation ; less movability ; increase in viscosity 4. SETTING PHASE : Chain growth finished ; no movability ; harden cement ; temperature gradually settles and undergoes volumetric shrinkage.

21. Basic terms Vertical height (vertical offset ) Medial offset (horizontal offset) Version of the femoral neck (anterior offset) Jump distance

22. VERTICAL HEIGHT (VERTICAL OFFSET) : It is determined primarily with the base length of prosthetic neck + length gained by modular head used MEDIAL OFFSET (HORIZONTAL OFFSET ) : Distance from the center of femoral head to a line throught the axsis of the distal part of the stem. It help in deciding moment of arm of the abducter musculature and joint reaction force.bone impingment

23. VERSION (ANTERIOR OFFSET) Refers to the orientation of neck in reference to the coronal plane (ante-version/retro-version) Important to attain stability of the joint Normally has 10-15 degree of ante-version of the femoral neck in relation to the coronal plane.

24. Size of femoral head , ratio of femur head and neck diameter and shape of neck of femur impart great effect On RANGE IF MOTION JUMP DISTANCE : It is the distance head must travel to escape rim of the socket (which is approx. ½ diameter of the head of femur ) IDEAL CONFIGRATION OF femur head : Trapezoidal neck Large diameter allow greater range of motion Non skirted head

25. PREOPERATIVE PLANNING RADIOGRAPHIC EXAMINATION: X RAY of pelvis with both hip AP view X-RAY of involves hip with thigh in AP and LAT view General status of the patient include status of knee , spine . Blood parameters required to know current and post-operative parameters. History of any other drug intake leading to large amount of blood loss Limb length disperancy or any other deformity

26. TEMPLATING Pre-operative templating is used to determine the appropriate femoral stem and unipolar and bipolar head size. In this normal hip is used as a template to duplicate normal leg and hip offset. Proper hip offset help to maintain proper soft tissue tension

27. Templating aids in : Selecting type of implant to restore center of rotation of hip Best femoral fit Tell us about the level of bone resection Neck length to restore equal limb length and femoral offset

28. TEMPLATING Position the hips in 15 degrees of internal rotation to delineate better femoral geometry and offset. Femoral offset will be underestimated when the hips are positioned in external rotation. standard pelvic radiograph, magnification is approximately 20%. Draw a line at the level of and parallel to the ischial tuberosities that intersects the lesser trochanter on each side and compare the two points of intersection and measure the difference to determine the amount of limb shortening.

29. the acetabular overlay templates on the film and select the size that matches the contour of the patient’s acetabulum without excessive removal of subchondral bone. The medial position of the acetabular template is at the teardrop and the inferior margin at the level of the obturator foramen. Mark the center of the acetabular component on the radiograph; this corresponds to the new center of rotation of the hip. Place the femoral overlay templates on the film and select the size that most precisely matches the contour of the proximal canal and fills it most completely . Make allowance for the thickness of the desired cement mantle.

30. Select the appropriate neck length to restore limb length and femoral offset. If no shortening is present, match the center of the head with the previously marked center of the acetabulum. If a discrepancy exists, the distance between the femoral head center and the acetabular center should be equal to the previously measured limb length discrepancy . When the neck length has been selected, mark the level of anticipated neck resection and measure its distance from the top of the lesser trochanter to use as a reference intraoperatively . Template the femur on the lateral view in a similar manner to ascertain whether the implant determined on the AP film can be inserted without excessive bone removaL

31. VARIOUS APPROACH TO HIP ARTHROPLASTY POSTERIOR APPROACHES : Gibsons approach ( postero -lateral approach) Southern or mores approach LATERAL APPROACHES : watson jones approach (antero-lateral approach) harris lateral approach modified hardinge approach ( transgluteal approach)

32. CASE : NAME : RAWEL KAUR AGE : 78 YEAR SEX : FEMALE PRESENTED TO THE OPD WITH A/H/O SLIP AND FALL 8 DAYS AGO WITH COMPLAIN OF : pain and swelling in left hip region. Inability to bear weight on left lower limb.

33. On examination : Inspection : ATTITUDE : left lower limb flexed abducted and externally rotated as compare to right lower limb. Overlying skin intact . Apparent shortening of left lower limb present as compare to right lower limb No fullness present over scarpa’s triangle. GT could not be seen on inspection. No appreciable wasting present over left thigh or calf muscle.

34. PALPATION : local temprature not raised as compare to the right side. Direct tenderness, indirect tenderness and thurst tenderness present over left lower limb GT is higher up on left side as compare to right side Loss of transmitted movement absent and could not be examined properly due to pain. RANGE OF MOTION : Limited movement at left hip joint with active ankle dorsiflexion present at left ankle DNVS : Distal pulses palpable with no sensory loss.

35. MEASUREMENT : RIGHT LEFT APPARENT LENGTH 101 CM 99 CM TRUE LENGTH 77 CM 75 CM SUPRATROCHANTRIC LENGTH 4 CM 2 CM THIGH 42 CM 41 CM CALF 36 CM 36 CM

36. DIAGNOSIS 1 week old fracture neck of femur left side Classification : AO classification Femur labelled as no 3 Neck fracture labelled as 31B Subcapital labelled as 31B1 Garden classification type IV

37. PRE OP X RAY

38. MANGEMENT DONE WITH : CEMENTED MODULAR BIPOLAR HEMIREPLACEMENT ARTHROPLASTY USING MODIFIED HARDINGE APPROACH (DIRECT LATERAL TRANSGLUTEAL APPROACH)

39. HARDINGE DIRECT TRANSGLUTEAL APPROACH Make patient lie in lateral position on operating table. Make a posteriorly directed lazy-J incision centered over the greater trochanter . Divide the fascia lata in line with the skin incision and centered over the greater trochanter. & Retract the tensor fasciae latae anteriorly and the gluteus maximus posteriorly, exposing the origin of the vastus lateralis and the insertion of the gluteus medius Incise the tendon of the gluteus medius obliquely across the greater trochanter, leaving the posterior half still attached to the trochanter. Carry the incision proximally in line with the fibers of the gluteus medius at the junction of the middle and posterior thirds of the muscle

40. Elevate the tendinous insertions of the anterior portions of the gluteus minimus and vastus lateralis muscles. Abduction of the thigh exposes the anterior capsule of the hip joint & Incise the capsule as desired. Neck osteotomised using an oscillating saw 1 cm proximal to the lesser trochanter (excessive neck resection can lead to shortening of lower limb and short femoral neck component can lead to prosthetic dislocation due to soft tissue laxity Lengthning of neck lead to increase pressure on the acetabular cartilage leading to erosion.) Head is removed with the help of cork-screw by incising the ligament teres .

41. Femoral head size should be measured using a caliper or head template. Smaller diameter head will result into assymetrical load in acetabulum leading to protusio acetabuli Head of larger diameter will not fully seated in the acetabulum leads to the risk of dislocation Box osteotome is used to open the femoral canal Sequential reaming is done with rasp until appropriate size of stem Trial stem is placed to confirm the size of stem Cementing is done through retrograde fashion using a cement gun or manual pressurization technique.

42. Prosthesis is inserted using manual force and light taps. Excessive cement is removed. Trial femoral head and neck is placed and hip is then reduced using traction and external rotation Hip stability is checked through : External rotation with hip in full extension Flexion and adduction Telescopic test

43. Trial stem is then replaced with appropriate prosthesis Head is again reduced Stability is reassessed Short external rotators and underlying capsule are repaired. Closure done in layers. Shift the patient in abduction by keeping a pillow between legs

44. POST OP X RAY

45. Post op comment GRUEN DIVIDED FEMORAL COMPONENT INTO 7 ZONES : to look for cement around the femoral prosthesis. The thickness in cement mantle should not drop below 2mm at anyplace i.e SHOULD NOT ALLOW METAL-BONE CONTACT POST OP CRITERIA for quality of cementing is divided into 4 criteria : Complete filling of medullary cavity by bone cement Slight radiolucency at bone cement interface Radiolucency involving 50-99 % of bone –cement interface(incomplete cement mantle Failure to fill the canal with cement (tip not covered)

46. COMPLICATIONS : erosion of acetabulum fracture of stem of prosthesis dislocation of prosthesis fracture of shaft of femur Retroversion and anteversion of prosthesis Neck length variation Sciatic nerve injury

47. Post operative management Knee ROM exercises and quad strengthening exercises on 1 st post op day. Mobilization started on 2 nd post – op day with the help of walker. Avoiding activities including excessive hip flexion and adduction Avoid squatting or sitting cross legged.

48. Thank you