This study evaluated the effect of joint position sense on compliance with the prosthesis, balance and functional performance in individuals with lower extremity amputation due to diabetic polyneuropathy. Study group consisted of 16 subjects with unilateral transtibial amputation due to diabetic polyneuropathy and control group consisted of 16 subjects with unilateral transtibial amputation due to traumatic reasons.

Proprioception is defined as the ability to distinguish the position of various body parts relative to each other and the ground through the sensory system (kinesthesia) and to perceive the forces acting on these body parts. Proprioception is a function that takes place mainly on a subconscious level. Information about the external environment we live in is obtained from the combination of nerve terminals in muscles and tendons, fibrous capsules around joints, vestibular and visual systems. The proprioceptive information obtained about the external environment through the peripheral nervous system is transferred to the central nervous system. The integration of these data collected from different sensory receptors is performed, and appropriate motor responses are initiated to ensure postural balance. Sensory loss due to pain, fatigue, effusion, trauma, or various neurological, musculoskeletal disorders and metabolic diseases such as diabetes often causes a decrease in proprioceptive sensation in these case groups. Peripheral nerve damage due to diabetic polyneuropathy (DPN), varies depending on the type of nerve fiber affected. As a result of damage to unmyelinated and small myelinated nerve fibers, light touch, pain and temperature senses are impaired while vibration and proprioception senses are decreased as a result of damage to large myelinated nerve fibers. Recent studies have shown that individuals with DPN are more likely to apply to the emergency department due to complications from fall accidents because they experience balance loss during activities of daily living compared to healthy non-diabetic individuals. Furthermore, foot biomechanics, which deteriorates owing to the loss of the normal neural feedback system caused by DPN, causes foot ulcerations by creating aberrant pressure distribution in the foot. In these people, non-healing lower limb ulcers account for 85% of planned lower extremity amputations. Due to the predicted loss of soft tissue, bone, and sensory receptors in the amputated limb following a prior lower extremity amputation, which results in musculoskeletal system degradation and destruction of the mechanoreceptors innervating these tissues, the way these individuals experience their surroundings changes and differentiates them from individuals who have been amputated due to traumatic causes. Diabetic amputees are unable to utilize their prostheses functionally following amputation due to their physical problems, which results in the majority of patients discontinuing usage of prosthesis. Although the number of test batteries developed to assess proprioceptive sense and the effectiveness of rehabilitation protocols used to assess proprioceptive sense in individuals with musculoskeletal disorders such as amputation is insufficient in the literature, it is believed that the existing batteries do not adequately assess proprioceptive sense. Additionally, no study has been conducted to determine the extent to which these patients' proprioceptive sensibility is altered following lower limb amputation due to DPN. For this reason, the study was planned to examine the effect of joint position sense on compliance with the prosthesis, balance and functional performance in individuals with lower extremity amputation due to DPN.

Inclusion Criteria:

Diabetic Group (DG):

1. Those who had unilateral transtibial amputation due to DPN
2. Between the ages of 40-65
3. Completed rehabilitation with prosthesis
4. Using prosthesis for at least 1 year
5. With standard size stump length
6. Without phantom sensation and pain
7. Able to walk at least 10 m independently
8. Gross lower extremity muscle strength at least moderate
9. No cognitive and mental problems
10. Diabetic nephropathy, retinopathy, ulceration etc. without secondary complications
11. Those who voluntarily agreed to participate in the research
12. Not included in any other concurrent study

Traumatic Group (TG):

1. Those who had trauma-induced unilateral transtibial amputation
2. Between the ages of 40-65
3. Completed rehabilitation with prosthesis
4. Using prosthesis for at least 1 year
5. With standard size stump length
6. Without phantom sensation and pain
7. Able to walk at least 10 m independently
8. Gross lower extremity muscle strength is at least moderate
9. Absence of cognitive and mental problems
10. Those who voluntarily agreed to participate in the research
11. Not included in any other concurrent study

Exclusion Criteria:

For all groups;

1. Having osteoarticular deformity in the knee joint
2. Having an orthopedic or neurological disease other than the cause of amputation
3. Significant and irreversible visual deficit
4. Body mass index (BMI)>30 kg/m²
5. Having a disability that makes it hard to complete any of the tests
6. Individuals with a history of cancer and receiving chemotherapy

De-identified individual participant data for all primary and secondary outcome measures will be made available.

Data will be available within 3 months with completion of the result report.

Requestors will be required to sign a Data Access Agreement.