HIP DISARTICULATION PROSTHETICS BY FEMY WIDYA NINGTYAS P D – III ORTHOTICS PROSTHETICS B 1

HIP DISARTICULATION PROSTHETICS HIP DISARTICULATION INTRODUCTION TO HIP DISARTICULATION PROSTHETICSCONSIDERATIONS PRESTIVE CONSIDERATIONS BIOMECHANICS PURPOSE OF HIP DISARTICULATION WEIGHT TRANSFER SUSPENSION CONTROL OF PROSTHETICS LIMB MOVEMENT MEDIO-LATERAL STABILITY THE ORIGINAL CANADIAN PROSTHETICS THE SPECIAL FEATURES OF THE CANADIAN PROSTHETICS FUNCTION OF THE PROSTHETICS AT DIFFERENT STAGES OF GAIT HIP DISARTICULATION AMPUTATION HISTORY AND REASON FOR HIP DISARTICULATION HIP DISARTICULATION PROCEDURE 2

HIP DISARTICULATION AMPUTATIONS 3 HIP DISARTICULATION HEMIPELVECTOMY

HIP DISARTICULATION mainly due to tumors and traumatic incidence The amputation is very extensive nearly 1/5 (or 20%) of the body mass is removed 4 The hemipelvectomy (also known as transpelvic amputation) is performed more rarely; it is even more extensive than the hip disarticulation as parts of the pelvis are also removed.

PROSTHETIC CONSIDERATIONS two types of amputation is mostly the same The hip disarticulation amputation provides a good end-bearing stump via the ischial tuberosity the hemipelvectomy amputation relies on weight transfer through soft tissues Both types have poor M-L stability 5

The functional loss of a hip disarticulation amputee is great as all joints are lost. replace the total limb function dependent on trunk flexor and extensor muscles for control of the prosthesis strong abductors for providing stability. 6

Comfort COG is shifted the non-amputated side Position of COG will vary with each amputee Body Weight condition muscle Energy consumption is increased from 80 – 125 % 7

PRESCRIPTIVE CONSIDERATIONS Patient who are well motivated and physically strong and active. The other factors that greatly influence long-term wear  Comfort  Optimal function  Cosmesis 8

Hip Disarticulation Amputation HISTORY AND REASONS FOR HIP DISARTICULATION HD amputation removes lower limb cutting through the hip joint. Hemipelvectomy part or all pelvic which is removed. HD have been since approximately 1750 Hemipelvectomy approximately

REASON FOR AMPUTATIONS ARE :  Malignant tumor  Extensive trauma  Uncontrolled infection  Conginetal deformity ( very rare ) 10

HIP DISARTICULATION PROCEDURE Was described by Boyd in 1947 The muscles are cut either at their origin or insertion 11

SURGICAL PROCEDURE ANTERIOR RACQUET Begins inferior to the anterior superior iliac spine, then it curves medially just inferior to the inguinal ligament. Posteriorly it passes distal to the ischial tuberosity and curves laterally to pass about 8 cm distal to the greater trochanter. swings anteriorly and proximally to join the beginning of the incision. The femoral vessels and nerve are ligated and cut. The superficial muscles at the anterior - medial are cut at their origins on the pelvis. Illiopsoas and the short external rotator muscles are cut at their insertions on the femur. The obturator artery and nerve are ligated and cut. The hip abductors are cut at their insertion on the femur. 12

Gluteus maximus is detached from its insertion on the femur. The hamstrings are cut at their origin at the ischial tuberosity. The sciatic nerve is ligated and cut. The hip joint capsule is cut circumferentially. Ligament teres is cut. Gluteus maximus is attached to the remains of the adductor muscles. The skin flaps are brought together and sutured 13

Socket Biomechanics PURPOSE OF HIP DISARTICULATION  Transfer weight to the prosthesis  Provide suspension of the prosthesis onto the body.  As a control movement of the prosthesis  Help control M-L stability. October 11,

WEIGHT TRANSFER Primally carries the weight through the ischial tuberosity Secondary load-bearing gluteal area. Socket total contact and proper relief for bony prominences such  SIAS  Iliac Crest  Posterior Spinous Processes of the vertebras 15

SUSPENSION Fitted above the iliac crests  Distance between the suspension and the ischial seat is correct.  If the distance is too great will pistoning accur.  If the distance is too short, excessive pressure on the iliac crest. October 11,

CONTROL OF PROSTHETIC LIMB MOVEMENT Patient is dependent on the trunk muscles to control and movement prosthesis. Socket must provide a very firm and fit in the anterior and posterior regions. creates wedges shape that gives firm contact and to control socket. Angle of the anterior wedges must match the hip joint. 17

MEDIO – LATERAL STABILITY  COG will give a downward force that is medial to the support point ( I ) at the ischial tuberosity during mid stance on the prosthetic.  The pelvic will tend to rotate a clockwise direction.  Socket must counteract this tendency.  Thus generating force onto the stump at lateral distal portion ( L )  The lateral proximal part of the sound side ( L 1 ) 18

THE ORIGINAL CANADIAN PROSTHESIS Canadian design, Sunnybrook Hospital in 1954Canadian design, Sunnybrook Hospital in 1954 The prosthesis is designed on basis of more sound biomechanical principles than previous designs.The prosthesis is designed on basis of more sound biomechanical principles than previous designs. Several modifications mainly in theSeveral modifications mainly in the  Improved component  Improved socket fit October 11, 2019October 11, 2019October 11, Basic principle still applies

THE SPECIAL FEATURES OF THE CANADIAN PROSTHESIS 1.The hip joint placed anteriorly to the weight bearing line ( H ) 2.The hip joint is wide and strong ( H* ) 3.A solid rubber bumper is placed behind the hip to prevent hyperextension (B) 4.The knee joint is placed posteriorly to the weight bearing line (K) 20

5.A line the hip and knee passes aproximately 25 – 50 mm behind the heel (A) 6.The joints are forced into extension when the patient's weight is applied, and the leg is a solid and stable unit. However, in a stumbling situation the leg will not be stable. 7.It is possible to choose a position for the hip joint so that the prosthetic knee joint will correspond with the normal knee joint both when the patient is standing and sitting. 21

This elastic strap has two roles : Prevent excessive hip flexion when the patient walks. Act to assist the knee extension. 22

FUNCTION OF THE PROSTHESIS AT DIFFERENT STAGES OF GAIT October 11,

 HEEL STRIKE 1.FOOT GRF THROUGH THE POSTERIOR TIP OF THE HEEL PLANTAR FLEXION MOMENT HEEL CUSHION OR PLANTAR FLEXION BUMPER MUST BE SOFT 2.KNEE JOINT FULL EXTENSION GRF PASSES ANTERIOR TO THE KNEE JOINT 3.HIP JOINT FLEXED GRF PASSES THROUGH THE HIP JOINT 4.SOCKET FORCES THE TRUNK TENDS TO FALL FORWARD FORCE ON THE STUMP WILL BE 24 DISTAL ANTERIOR PROXIMAL POSTERIOR DISTAL

 FOOT FLAT 1.FOOT GRF moves anteriorly The foot plantar flexes The heel cushion must be very soft 2.KNEE JOINT Still fully extended GRF passes more anterior 3.HIP JOINT GRF still passes the centre of the hip joint 4.SOCKET FORCES Trunk to fall forward Forces will still be : 25 DISTAL ANTERIOR PROXIMAL POSTERIOR DISTAL

 MID STANCE 1.FOOT GRF continues to move more anterior 2.KNEE GRF are anterior 3.HIP GRF moved posterior The hip joint is hekd firmly against the extension stop. 4.SOCKET FORCES All the amputee’s weight is now on the prosthesis Not A-P rotational forces Only distal weight bearing force are present. 26

 HEEL – OFF 1.FOOT GRF move forward to the toe of the foot 2.KNEE GRF are still to the knee joint 3.HIP GRF continue to move posterior to the hip joint 4.SOCKET FORCES Socket forces on the stump will now be 27 Posterior proximal Anterior distal distal

 TOE – OFF 1.FOOT GRF pass through the toe of the foot. Some GRF are being transferred to the sound side leg 2.KNEE GRF move posterior 3.HIP GRF are posterior to the hip joint 4.SOCKET FORCES Forces on the stump will be 28 Posterior proximal Anterior distal distal

SWING PHASE  ACCELERATION Foot is lifted off the floor Hip fully extended Added elastic strap to assist knee extension  DELERATIONS The Hip to swing forward The knee full extension  MID SWING Knee and hip in full extension Toe clerance can be obtained by the following  The prosthesis shortened up to 1 cm  The amputee keeps the trunk vertical so that hip joint is forward and as high as possible  The amputee liftsthe hip on the prosthetic side (lateral flexion of the trunk).  The amputee actively plantar flexes the sound foot (vaulting) 29

October 11,