Functional Hip Strength Improvement in Knee Osteoarthritis Following Single-Dose PRP and a 6-Week Home Exercise Program

Functional Hip Strength and Pain Changes in Women With Knee Osteoarthritis Following a Single-Dose Intra-Articular Platelet-Rich Plasma Injection and a 6-Week Home Exercise Program: A Single-Group Longitudinal Study

This single-group longitudinal study evaluated changes in hip stability isometric strength, knee muscle strength, and activity-related pain in women with knee osteoarthritis following a single-dose intra-articular platelet-rich plasma (PRP) injection and a 6-week home exercise program. Outcomes were assessed at baseline (5 days post-injection), week 6, and week 12. The intervention included strengthening exercises for knee and hip muscle groups performed three times per week and regular walking encouragement with weekly phone follow-up for adherence.

Study Overview

• Status: Completed
• Conditions: Knee Osteoarthritis (OA)
• Intervention / Treatment: Biological: Platelet-Rich Plasma (PRP) Injection; Behavioral: Home Exercise Program

Detailed Description

Participants with unilateral symptomatic knee osteoarthritis performed a standardized 6-week home strengthening program (knee extensors/flexors; hip extensors/abductors/external rotators) three times weekly and were encouraged to walk regularly. Hip Stability Isometric Test (HipSIT), quadriceps/hamstring strength (hand-held dynamometry, normalized to body mass), and activity pain (VAS 0-10) were measured at baseline, week 6, and week 12 to evaluate functional strength and symptom changes after PRP plus exercise.

• Study Type: Interventional
• Enrollment (Actual): 27
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • MErkez
    • Elâzığ, MErkez, Turkey (Türkiye), 23200
      • Fırat Üniversitesi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Female patients aged 45-70 years.
• Radiographic knee osteoarthritis: Kellgren-Lawrence grade II-III in the affected knee and grade II or less in the unaffected knee.
• Unilateral knee pain during activity with VAS score ≥5 (for at least the past 3 months).
• Referred to physiotherapy following a unilateral single-dose PRP injection.

Exclusion Criteria:

• Any intra-articular knee injection within the past 6 months.
• Regular lower-extremity strengthening exercise or non-pharmacological treatment for knee OA within the past 6 weeks.
• History of lower-extremity surgery.
• History of neurological, rheumatological and/or cognitive diseases.
• Unable to use a telephone.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Single Group: PRP Injection + Home Exercise Program; All participants received a unilateral single-dose intra-articular platelet-rich plasma (PRP) injection for symptomatic knee osteoarthritis, followed by a 6-week home-based strengthening and functional exercise program performed 3 times per week. The exercise program targeted knee extensors/flexors and hip extensors/abductors/external rotators. Participants were encouraged to walk at least 30 minutes on at least 5 days per week and were contacted weekly by phone to support adherence.

Biological: Platelet-Rich Plasma (PRP) Injection; A single unilateral intra-articular autologous platelet-rich plasma (PRP) injection was administered to the affected knee. Baseline assessments were conducted 5 days following the injection.; Other Names: PRP; Behavioral: Home Exercise Program; Home-based exercise program performed 3 times per week for 6 weeks, designed to strengthen knee extensors/flexors and hip extensors/abductors/external rotators. Exercises included: quadriceps strengthening (supine isometric contractions with 5-second hold; seated knee extension with 5-second hold; straight leg raise with 5-second hold), hamstring strengthening (supine isometric contractions with 5-second hold; prone active knee flexion with 5-second hold), hip stabilizer strengthening (clamshells and side-lying hip abduction with 5-second hold), and functional exercises (step-ups, forward touchdowns from a step, side stepping, sit-to-stand from a chair without using arms, and partial wall squats), typically 10-15 repetitions. Participants were also encouraged to walk at least 30 minutes on at least 5 days per week, and adherence was supported via weekly telephone contact.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hip Stability Isometric Test (HipSIT) strength (N/kg), affected side	Hip stability isometric strength (combined hip extensor, abductor and external rotator maximum isometric strength) assessed using a hand-held dynamometer during the Hip Stability Isometric Test (HipSIT). The test is performed in side-lying "clam" position (hip 45° flexion, knee 90° flexion). Three maximal trials (5 seconds each) are performed and the maximum force output (N) is normalized to body mass (N/kg).	Baseline (5 days post PRP injection), Week 6, Week 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quadriceps femoris isometric strength (N/kg), affected side	Maximum isometric quadriceps strength measured with a hand-held dynamometer in sitting position (hip 90° flexion, knee semi-flexion), with the dynamometer placed on the anterior surface of the ankle. Three maximal trials (5 seconds each) are performed and the maximum force output (N) is normalized to body mass (N/kg).	Baseline (5 days post PRP injection), Week 6, Week 12
Hamstring isometric strength (N/kg), affected side	Maximum isometric hamstring strength measured with a hand-held dynamometer in prone position (hip neutral, knee flexion 90°), with the dynamometer placed on the proximal posterior surface of the ankle. Three maximal trials (5 seconds each) are performed and the maximum force output (N) is normalized to body mass (N/kg).	Baseline (5 days post PRP injection), Week 6, Week 12
Knee pain during activity (Visual Analog Scale, 0-10)	Pain severity during activity assessed using a 10-cm Visual Analog Scale (VAS) ranging from 0 (no pain) to 10 (worst imaginable pain).	Baseline (5 days post PRP injection), Week 6, Week 12

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Strength symmetry indices (QI, HI, HipI), %	Strength symmetry indices calculated as (affected side isometric strength / unaffected side isometric strength) × 100 for HipSIT (HipI), quadriceps (QI), and hamstrings (HI).	Baseline (5 days post PRP injection), Week 6, Week 12

Collaborators and Investigators

• Sponsor: Firat University

Study record dates

Study Major Dates

• Study Start (Actual): July 8, 2025
• Primary Completion (Actual): December 12, 2025
• Study Completion (Actual): December 13, 2025

Study Registration Dates

• First Submitted: December 13, 2025
• First Submitted That Met QC Criteria: December 13, 2025
• First Posted (Actual): December 29, 2025

Study Record Updates

• Last Update Posted (Actual): December 29, 2025
• Last Update Submitted That Met QC Criteria: December 13, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Pain; Knee osteoarthritis; exercise therapy; platelet-rich plasma; Hand-held dynamometer; hip muscle strength
• Additional Relevant MeSH Terms: Neurologic Manifestations; Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain; Osteoarthritis, Knee; Therapeutics; Drug Administration Routes; Drug Therapy; Injections
• Other Study ID Numbers: FU_MGBeydagi_PRP_B_2025/12/150

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No