Hip Disarticulation & Hemipelvectomy Rehab

• Hip disarticulation and hemipelvectomy are rare, so rehab professionals lack familiarity with prosthetic management.
• These patients face challenges using a prosthesis due to increased energy demands and slower walking.
• Successful use depends on motivation, single-leg balance, core strength, and prosthetic management.

Introduction

• Less than 2% of amputations are at the hip disarticulation level.
• Physiatrists, therapists, and prosthetists may not be familiar with fitting considerations and biomechanics.
• Higher rejection rates are due to energy requirements, weight, and body coverage.
• Successful long-term acceptance ranges from 35% to 43%.
• Muscular control is reduced, limited to pelvis and lumbar spine movements.
• Middle-aged individuals walk 40% slower and expend 80% more energy than able-bodied.
• Elderly amputees face even higher energy requirements.
• Some elderly amputees can achieve successful prosthesis use with adequate fitness.
• Technologic advances, such as lighter components, help improve prostheses.
• Maintaining use can be challenging
• Reduced energy requirements and increased speed of alternative mobility preclude prosthetic ambulation.
• Elderly amputees can move faster with a wheelchair (2x) expending less energy (25%).
• Hemipelvectomy prosthesis users take 43% longer to walk 400m compared to crutches.
• Successful users may limit wear time to 6 hours per day.
• New technologies are transforming outcomes for hip disarticulation.

Evaluation and Indicators of Success

• Successful fitting relies on patient's motivation, balance, core strength, and load-bearing tolerance.
• Greater motivation is needed compared to transfemoral or transtibial amputation.
• The possibility of successful prosthesis use can only be assessed with proper expectation setting for the patient.
• Unrealistic expectations leads to early rejection.
• Superior one-leg balance is a positive indicator as is its needed to don and ambulate with a hip disarticulation prosthesis using minimal assistance.
• Core abdominal muscle strength should be assessed with a pelvic tilt.
• Successful prosthesis users maintain low body weight for pelvic tilt in the prosthesis.
• Redundant or fleshy tissue should be noted to create reaction surfaces.
• The ischial tuberosity should be evaluated for its load-bearing tolerance.
• Gluteal tissue should be assessed for its ability to supplement axial loading.
• Bony prominences of the pubis and iliac crests and the residual femoral head should be noted.

Prosthetic Componentry: Hip Disarticulation

• Endoskeletal componentry is standard because of light weight and adjustability.
• Assessing potential/ability is critical in component selection.

Feet

• Single and multiaxial feet can increase knee stability.
• Dynamic response feet are preferred due to light weight.
• The additional benefits of energy storage and return associated with these feet are only observed in more active users
• Lightweight carbon fiber feet allow smoother transition from loading.

Knees

• Single-axis knees were the predominant choice for hip disarticulation prostheses.
• Single-axis knees with stance control are contraindicated.
• Sagittal stability is provided by hip and knee alignment, mechanical stability isn't usually necessary.
• Active users may prefer knees with stability features for terrain negotiation.
• Polycentric knees are chosen for individuals wanting stability.
• Polycentric knees with hydraulic swing control can be used but are heavier for fast ambulation speeds.
• Microprocessor-controlled knees enable real-time adjustments to stance control.

Hips

• Hip joint design has remained substantially unchanged over the years
• Originally mounted laterally, near the anatomic hip.
• Joints were locked for standing/walking and were then unlocked for sitting
• Colin McLaurin introduced the Canadian hip disarticulation prosthesis, still in use.
• The design has an anteriorly mounted hip joint.
• Which is passively stabilized during stance through posterior positioning of the gravity center.
• Newer modular systems have more compact designs and low profile attachments that make sitting easier.
• New internal adjustable spring mechanisms provide hip extension assist.
• Carbon composite strut systems have been designed for use distal to joints.
• Latest technology is a hydraulic helical design with unique features.
• It addresses deviants in users of hip-level prostheses.
• It hydraulically controls flexion in the swing phase and extension in the first phase.
• It allows the user to vary cadence and cushion loading.
• The joints geometry compensates for internal rotation of the pelvis in the swing phase.
• The joint incorporates hip flexion bands.
• Some improvements in gait biomechanics have been made and performance of daily living using this system compared with single-axis hip joints.

Height Considerations

• When using mechanical hip joints, there is no hip flexion in the early swing phase and minimal knee flexion at mid swing.
• Limb length differences affect the users ability to obtain swing phase ground clearance.
• Hip disarticulation prosthesis feels "long" and is made slightly shorter than the other leg.
• The user will vault on the sound leg, or hike the hip of the residual limb to ensure toe clearance.

Creating the Hip Disarticulation Interface

• The hip disarticulation interface must serve four purposes: adequate coronal support; sagittal capture of pelvic movements; secure, comfortable suspension; and appropriate weight-bearing surfaces and contours.
• New thermoplastic materials have been developed that better improve socket comfort, especially over the iliac crests
• Traditional hip disarticulation socket designs encompass the affected pelvis, contain the gluteal tissue and ischial tuberosity, and provide mediolateral stability by compressing the contralateral pelvis toward the affected side through the design of the interface.
• Suspension is accomplished by compression over one or both iliac crests, and an anterior closure is normally used.
• Novel socket design configurations include the creative use of suction or vacuum designs with reduced contralateral trim lines.
• Traditional hip disarticulation socket designs encompass the affected pelvis, contain the gluteal tissue and ischial tuberosity, and provide mediolateral stability by compressing the contralateral pelvis toward the affected side through the design of the interface.

Creating the Hemipelvectomy Interface

• When designing the socket for a hemipelvectomy prosthesis, without pelvic anatomy for weight-bearing, additional soft-tissue compression and more aggressive trim lines must be designed for.
• Prosthesis design for this level of amputation can be very challenging because of limited weight-bearing area and restrictive trim lines leading to a loss of range of

Prosthetic Alignment

• Stability of the hip disarticulation prosthesis relies primarily on the alignment of the components in relation to the socket in the sagittal plane.
• Alignment principles involve the projection of a line in the sagittal plane from the prosthetic hip joint center through the prosthetic knee axis.
• Reference lines used often today.
• More contemporary sagittal alignments will use a plumb line from the sagittal socket bisector. This alignment will position the socket over the prosthetic knee axis and prosthetic foot to provide biomechanical stability for the user.
• The hip joint estimates the bisection of the socket.
• Most traditional hip, the length of the prosthesis is made slightly shorter than the sound side.

Gait Biomechanics and Physical Therapy

• To align, adjust, and train users it's helpful to have knowledge of prosthetic function when walking.
• Core training to shift weights and balance are factors for walking success.
• Maintaining upright posture and proper heel contact/stride is important to begin ambulating.
• Ground reaction force passes posterior to the prosthetic foot ankle with hip joint.
• When a user comes to the midstance phase of gait, the ground reaction line moves anterior to the ankle joint, anterior to the knee joint, and continues to pass posterior to the hip joint.
• An intimately fitted socket in the lumbar region and compression of the abdominal region anteriorly contribute to controlling knee flexion to initiate the swing phase.
• During the phase of initial swing suspension becomes very important.
• During midswing the knee comes to full extension.

Summary

• The group including the patient, doctor, and physical therapist are important for success!
• The care workers must get what the patient wishes and their condition and motivation.
• Advanced materials can help those with care.