Vibration Applications After Total Knee Arthroplasty in Osteopenic Women

Istinye University48 enrolled

Overview

Osteoarthritis (OA) is a chronic degenerative disease characterized by the destruction of articular cartilage, leading to functional impairment of surrounding bone and soft tissues. It is a major global public health problem, with the knee joint being the most commonly affected site. Treatment modalities include exercise, diet, oral non-steroidal anti-inflammatory drugs (NSAIDs), intra-articular injections, and total knee arthroplasty (TKA). TKA is indicated in cases of severe pain, functional loss, deformity, and limited range of motion when conservative methods are no longer effective. However, some patients may continue to experience deformity and functional deficits after surgery. Postoperative quadriceps weakness and decreased functional capacity can negatively affect patient prognosis. Following TKA, bone mineral density (BMD) tends to decrease during the first three months. The reduction in BMD and the increase in bone resorption may elevate the risk of implant loosening or periprosthetic fracture. Bone turnover markers (BTMs), which are enzymes or degradation products released into circulation by bone cells, reflect bone remodeling processes and can help identify increased fracture risk. A significant proportion of TKA candidates are osteopenic. Since osteopenic individuals make up a larger segment of the population, most fragility fractures actually occur in individuals with osteopenia rather than osteoporosis. Therefore, BMD levels and the presence of osteopenia or osteoporosis should be taken into account in patients undergoing TKA. To preserve both bone quality and muscle mass, early rehabilitation and progressive weight-bearing on the operated limb are considered essential. These strategies may improve both BMD and BTMs. Whole-body vibration (WBV) therapy has been suggested as an effective and safe method to increase mechanical loading on the bones. WBV can be applied in a static standing position on a vibration platform or combined with simultaneous exercise. Given the limited availability of targeted strategies to improve bone remodeling and BTMs after TKA, and the lack of clarity regarding the optimal WBV protocol, this study aims to investigate the effects of different vibration applications on bone turnover markers, functionality, muscle strength, pain intensity, pressure pain threshold, range of motion, proprioception, edema, and muscle biomechanical properties in osteopenic women following TKA. Participants will be randomly assigned to one of three groups: WBV only, WBV combined with exercise (WBV-E), or control. All groups will receive traditional rehabilitation three times per week for four weeks after surgery. WBV interventions will begin at the end of the fourth postoperative week, once patients are deemed ready. While WBV groups will receive additional vibration therapy, the control group will continue traditional rehabilitation alone. Outcomes will be evaluated using bone turnover markers, the Timed Up and Go (TUG) test, the 30-Second Chair Stand Test, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), measurements of muscle biomechanical properties and strength, pain intensity and pressure pain threshold, joint range of motion, proprioception, and edema.

Interventions

Whole Body Vibration TherapyBEHAVIORAL

Participants receive whole-body vibration therapy in a static upright position on a vibration platform (Power Plate My5). The intervention is applied 3 times per week for 8 weeks, progressively increasing frequency from 8 Hz to 40 Hz and amplitude from 2 mm to 5 mm. Each session lasts up to 15 minutes. No exercise is performed during the vibration.

Whole Body Vibration with ExerciseBEHAVIORAL

Participants perform lower extremity strengthening exercises on a vibration platform simultaneously with whole-body vibration. The protocol includes lunges, squats, heel raises, and ball squeezes. Vibration frequency ranges from 30 to 40 Hz and amplitude from 2 to 5 mm. Sessions are performed 3 times per week for 8 weeks, with duration progressing from 2 to 18 minutes depending on tolerance.

Conventional PhysiotherapyBEHAVIORAL

Participants receive standard post-total knee arthroplasty physiotherapy 3 times per week for 12 weeks, lasting 40 to 70 minutes per session. In addition, a home-based exercise program is performed 3 times daily. The program includes range of motion, strengthening, and balance exercises. No vibration therapy is applied in this group.

Eligibility

Sex: FEMALEMin age: 60 YearsMax age: 75 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Scheduled to undergo unilateral, primary, cemented total knee arthroplasty (TKA) using a posterior cruciate ligament-sacrificing technique and medial parapatellar approach due to knee osteoarthritis * Ability to speak and understand Turkish * Ability to comprehend both verbal and written information * A T-score between -2.5 and -1 (i.e., -2.5 \< T-score \< -1) measured by DXA in the lumbar spine, total hip, or femoral neck within the past year Exclusion Criteria: * Scheduled for revision TKA * American Society of Anesthesiologists (ASA) physical status classification score higher than 3 * History of major surgery on the limb to be operated * Presence of comorbid diseases such as rheumatoid arthritis or cancer * Presence of a neurological condition causing functional impairment * Diagnosed psychiatric disorder * Dementia * Disorders affecting the vestibular system * Having undergone anesthesia for any reason within the last month * Regular use of hypnotic or anxiolytic medications * Hearing or vision impairment not correctable by hearing aids or glasses * Presence of endocrine system disorders * Secondary osteoporosis or history of osteoporotic fracture * Metabolic bone diseases or chronic illnesses potentially affecting bone metabolism * Use of medications known to affect bone metabolism (e.g., menopausal hormone therapy, bisphosphonates, raloxifene, calcitonin, growth hormone, parathyroid hormones, corticosteroids) within 6 months prior to the start of the study

Outcomes

Primary Outcomes

Timed Up and Go (TUG) Test Score

This test evaluates functional mobility and performance-based activity limitation. Participants are instructed to stand up from a standardized chair (height: 44 cm; depth: 26 cm), walk 3 meters at a normal pace, turn around, return, and sit down. The time taken to complete the task is recorded. The TUG test is a valid and reliable indicator of physical function in individuals with knee osteoarthritis.

Time frame: Baseline (Week 4 post-op) and 12th week (Post-intervention)

Bone Turnover Marker (Serum Procollagen Type I N-terminal Propeptide (PINP) Level)

Serum PINP levels will be measured using enzyme-linked immunosorbent assay (ELISA) to evaluate bone formation activity. Results will be expressed in nanograms per milliliter (ng/mL). Blood samples will be collected at three time points: pre-surgery, week 4 post-surgery, and week 12 post-surgery

Time frame: Pre-surgery, Week 4, Week 12

Bone Turnover Marker (Serum Osteocalcin (OCN) Level)

Serum concentration of Osteocalcin (OCN )will be measured using enzyme-linked immunosorbent assay (ELISA) to evaluate bone turnover. Units will be expressed in nanograms per milliliter (ng/mL). Blood samples will be collected at 3 time points: pre-surgery, week 4, and week 12 post-surgery.

Time frame: Pre-surgery, Week 4, Week 12

Bone Turnover Marker (Serum C-terminal Telopeptide of Type I Collagen (CTX) Level)

C-terminal Telopeptide of Type I Collagen (CTX) concentrations will be analyzed using enzyme-linked immunosorbent assay (ELISA) to evaluate bone resorption. Results will be expressed in nanograms per milliliter (ng/mL). Serum will be collected at three time points: before surgery, and at 4 and 12 weeks after surgery.

Time frame: Pre-surgery, Week 4, Week 12

Bone Turnover Marker (Serum N-terminal Telopeptide of Type I Collagen (NTX) Level)

N-terminal Telopeptide of Type I Collagen (NTX) will be measured with enzyme-linked immunosorbent assay (ELISA) kits to assess bone resorption activity. Results will be expressed in nanomoles of bone collagen equivalents per liter (nmol BCE/L), according to kit instructions. Samples will be drawn at three time points: pre-surgery, week 4, and week 12 post-surgery.

Time frame: Pre-surgery, Week 4, Week 12

30-Second Chair Stand Test

Participants are asked to cross their arms over their chest and stand up from a 44 cm standard chair as many times as possible within 30 seconds. The number of correct repetitions is recorded to assess lower limb functional strength and endurance.