CurrentUnitedHealthcarePolicy DME 005.31

Mechanical Stretching Devices

Policy governing coverage of mechanical stretching devices (low-load prolonged-duration stretch, static progressive stretch, and patient-actuated serial stretch) for treatment of joint contractures of the upper and lower extremities for UnitedHealthcare members.

Policy Summary

PayerUnitedHealthcare

PolicyMechanical Stretching Devices

Policy CodePolicy DME 005.31

Change TypeNo material change

Effective DateSeptember 1, 2025

Next Review DateN/A

Key ActionSubmit relevant medical records to demonstrate existing joint contracture and use as adjunct to therapy as applicable.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

Sep 1, 2025Effective date

LLPS coveredCoverage stance

SPS & PASSNot covered

E1399, E1800–E1841HCPCS codes listed

49Cochrane studies

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LLPS (covered)

Covered when ALL of the following are met

LLPS covered indication: Low-load prolonged-duration stretch (LLPS) devices as an adjunct to therapy are proven and medically necessary for treating existing joint contractures of the upper and lower extremities.

Supported by randomized controlled trials, observational studies, case series, and medical community acceptance for persistent post-injury or post-surgical joint stiffness; limited evidence for chronic conditions.

SPS and PASS (not medically necessary)

Not medically necessary

SPS and PASS not covered: Static progressive stretch (SPS) devices and patient-actuated serial stretch (PASS) devices are considered unproven and not medically necessary for treating joint contractures of the upper and lower extremities due to insufficient evidence of efficacy and inadequate study of safety and long-term outcomes.

Policy explicitly lists SPS and PASS as unproven and not medically necessary; systematic reviews and statements note insufficient evidence and lack of well-designed trials.

Evidence summary / coverage stance

Evidence-based conclusions summarized in the document:

PASS devices: Patient-actuated serial stretch (PASS) devices: clinical evidence is not sufficient to demonstrate effectiveness for treating joint contractures; safety, efficacy, and long-term outcomes are inadequately studied.

Systematic reviews and the policy state that well-designed clinical trials are lacking and available evidence is insufficient.

SPS and other mechanical devices: Static progressive stretch (SPS) and other mechanical stretching devices have mixed evidence: some small studies and systematic reviews report improvements in range of motion for specific indications (e.g., post-TKA, elbow stiffness), but overall systematic reviews found no convincing superiority and evidence limitations prevent strong conclusions.

Cochrane-style review (Harvey et al.) found stretch interventions not clearly effective; small, heterogeneous studies and short follow-up limit conclusions.

LLPS evidence: Low-load prolonged-duration stretch (LLPS) devices: randomized controlled trials, observational studies, and case series confirm benefits for relieving persistent joint stiffness after injury or surgery, but evidence is minimal for chronic conditions such as RA, cerebral palsy, or plantar fasciitis.

Policy cites RCTs and observational evidence supporting LLPS for post-injury/surgical stiffness while noting limited evidence for chronic fixed contractures.

Available evidence supports the use of dynamic low-load prolonged-duration stretch (LLPS) devices for relieving persistent joint stiffness after injury or surgery, but there is insufficient evidence to support their effectiveness for rehabilitation of joints in chronic conditions. Specifically, peer-reviewed literature is limited for indications such as chronic joint stiffness or chronic fixed contractures related to conditions like rheumatoid arthritis, cerebral palsy, or plantar fasciitis.

There is no indication in the evidence base that supports coverage of patient-actuated serial stretch (PASS) devices for any indication. Clinical studies and systematic reviews do not provide sufficient data to establish safety, efficacy, or long-term outcomes for PASS devices.

Based on the current literature, static progressive stretch (SPS) splints and patient-actuated serial stretch (PASS) devices are considered unproven and not medically necessary for treatment of joint contractures of the upper and lower extremities. The policy lists both device types as not medically necessary due to insufficient evidence of clinical benefit when used alone or in combination with standard physical therapy.

Systematic reviews and pooled analyses of stretch interventions, including splinting, show mixed and generally limited results. A comprehensive review found no consistent advantage of any particular stretch intervention and concluded that stretch, including splinting, is not clearly effective for treatment or prevention of contractures; short- and long-term effects for many populations remain uncertain. For LLPS devices, randomized and observational studies support benefit for post-injury or post-surgical stiffness, but evidence is minimal or lacking for many chronic conditions.

Coding

Applicable HCPCS codesHCPCS

E1399	Durable medical equipment; miscellaneous.
E1800	Dynamic adjustable elbow extension and flexion device, includes soft interface material.
E1801	Static progressive stretch/patient actualated serial stretch elbow device, extension and/or flexion, with or without range of motion adjustment, includes all components and accessories.
E1803	Dynamic adjustable elbow extension only device, includes soft interface material.
E1804	Dynamic adjustable elbow flexion only device, includes soft interface material.
E1806	Static progressive stretch wrist device, flexion and/or extension, with or without range of motion adjustment; includes all components and accessories.
E1807	Dynamic adjustable wrist extension only device, includes soft interface material.
E1808	Dynamic adjustable wrist flexion only device, includes soft interface material.
E1810	Dynamic adjustable knee extension and flexion device, includes soft interface material.
E1811	Static progressive stretch/patient actuated serial stretch knee device, extension and/or flexion, with or without range of motion adjustment; includes all components and accessories.

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Provider Actions & Billing

Billing Rule

Code list / Prior authorization note

The HCPCS codes listed in this policy are provided for reference and must be used for claims submission and prior authorization workflows when applicable. Inclusion of a code in this policy does not guarantee coverage or payment; benefit coverage is determined by the member-specific benefit plan and any applicable laws or mandates.

Use HCPCS codes on claims and prior authorization requests (see Applicable Codes list: E1399, E1800–E1841, etc.).
Listing of a code does not imply coverage or guarantee reimbursement.

Prior Authorization

Prior authorization

Prior authorization requirements depend on the member-specific benefit plan. Verify prior authorization status through UnitedHealthcare tools or the member’s benefit plan before device procurement or delivery.

Check member-specific plan and applicable state or federal mandates.
Use UnitedHealthcare prior authorization portals or contact provider services for plan-specific requirements.

Note

Adjunct to therapy

These devices are intended to be used as an adjunct to therapist-directed care to provide frequent, controlled joint mobilization and may replace some physical therapist–directed sessions when clinically appropriate. Document the role of the device in the therapy plan, including how it supplements or substitutes therapist-provided treatments.

Explain how the device augments therapist-directed therapy and which PT sessions, if any, are being replaced.
Specify treatment goals, frequency/duration of device use, and measurable ROM objectives in the plan of care.

Documentation Required

Documentation requirements

Medical record documentation may be required to determine whether the member meets clinical criteria for coverage. Maintain and submit supporting records when requested.

Include detailed history, diagnosis, baseline and follow-up ROM measurements, prior PT interventions and response, and the treating clinician’s rationale for device selection.
Attach the member-specific benefit plan reference and any prior authorization approval when submitting claims.

Note

Plan document requirement

Always reference the member-specific benefit plan document to determine coverage and any applicable mandates. In case of conflict, the member-specific benefit plan governs.

The Clinical Policy is informational and does not replace the member’s plan document.
Confirm state or federal mandates that may require coverage inconsistent with this policy.

Denial Risk

Denial triggers — PASS and SPS devices

Requests for Patient-Actuated Serial Stretch (PASS) or Static Progressive Stretch (SPS) devices for treatment of joint contractures are denial triggers per this policy; these devices are considered unproven and not medically necessary when used alone or combined with standard PT due to insufficient evidence.

PASS devices (patient-controlled mechanical stretching) — not medically necessary.
SPS splint devices — not medically necessary.

Denial Risk

Insufficient evidence for PASS devices

Clinical evidence is insufficient to support coverage for PASS devices. Coverage may be denied when PASS devices are requested because published literature lacks well-designed trials demonstrating safety, efficacy, and long-term outcomes.

If requesting coverage for a PASS device, provide robust clinical justification and any supportive trial data; absence of such evidence may result in denial.

Definitions

Mechanical stretch devices / Dynamic splinting systems — definition and key characteristics

DefinitionAdjustable spring-loaded devices (dynamic splinting systems) designed to provide low-load prolonged-duration stretch (LLPS) to maintain or restore joint range of motion; prefabricated and custom units available for elbow, wrist, fingers, knee, ankle, and toes.

Primary purposeUsed for prevention and treatment of joint contractures following immobilization from surgery, disease, or trauma by providing frequent, consistent joint mobilization as an adjunct to physical therapy.

Form factorsPrefabricated units for extension and flexion and custom dynamic splints when prefabricated units are ineffective due to limb size/shape or load/material needs.

Operation settingIntended for use in hospital or home settings; can be used while individuals are asleep or at rest to deliver prolonged passive stretching.

Alternate nameAlso referred to as dynamic splinting systems or mechanical stretch devices.

Static progressive stretch (SPS) — definition and distinguishing features

DefinitionDevices that hold the joint in a set position and allow manual modification of joint angle (inelastic traction) to apply static progressive stretch.

MechanismStatic positioning with manual adjustment of angle; does not exert dynamic stress on tissue and does not allow active or passive motion during application.

Use caseUsed as a splinting technique among multiple PT modalities for restoring joint ROM, often combined with other treatments.

Distinguishing featureUnlike LLPS, SPS devices do not deliver spring-loaded or prolonged dynamic load — they maintain set position with incremental angle changes.

Patient-actuated serial stretch (PASS) — definition and device mechanism

DefinitionDevices that provide an adjustable low- to high-level load to the joint using pneumatic or hydraulic systems that the individual can adjust.

Device mechanismLoad delivered via pneumatic (e.g., Extensionaters) or hydraulic (e.g., Flexionaters) components allowing patient-actuated serial stretching per a customized treatment plan.

CustomizationProtocols include individualized education and a customized treatment plan; different PASS devices are available depending on the joint being treated (knee/ankle, knee, shoulder).

LLPS — definition of low-load prolonged-duration stretch devices

DefinitionLow-load prolonged-duration stretch (LLPS) devices provide prolonged passive stretching, often delivered while the individual is asleep or at rest, to maintain or restore joint ROM.

MechanismDelivered by adjustable spring-loaded (dynamic) splinting systems that apply a low continuous load for extended periods.

Typical indicationsUsed for treatment of existing joint contractures of the upper and lower extremities as an adjunct to therapy following immobilization, injury, or surgery.

Mechanical stretching devices (examples and FDA classification)

ExamplesDynasplint, Ultraflex, Pro-glide Knee/Elbow/Wrist (DeRoyale Advance Dynamic ROM).

FDA classificationCategorized under product code ION as Class I medical devices (510(k) exempt); manufacturers are exempt from premarket notification procedures.

Regulatory noteFDA classification provided for informational purposes only; FDA approval/clearing alone is not a basis for coverage decisions.

Medical Necessity

LLPS necessity

Medical necessity summary for LLPS device types

LLPS necessity: Member has an existing joint contracture of an upper or lower extremity and the LLPS device is prescribed as an adjunct to physical therapy to maintain or restore joint range of motion.

Coverage is supported for persistent post-injury or post-surgical stiffness based on available randomized and observational studies; limited evidence for chronic systemic conditions.

Device use context: Device use is intended to provide prolonged passive stretching (often at rest or during sleep) to supplement therapist-directed interventions, replacing some in-person mobilization sessions where appropriate.

Dynamic splinting systems are adjustable, spring-loaded LLPS devices for elbow, wrist, fingers, knee, ankle, toes; custom units allowed when prefabricated units are ineffective.

Documentation requirement: Relevant medical records must document the existing joint contracture and justification for LLPS device use as an adjunct to therapy; benefit determination is subject to the member-specific plan.

Providers should submit records demonstrating contracture and prior/ concurrent therapy; verify member benefit plan for coverage specifics.

Scenarios from evidence

Clinical scenarios described in the literature where devices were applied and outcomes measured:

Postoperative stiffness after TKA: Multimodal physical therapy programs that included static progressive splinting showed feasibility and in a small cohort avoided manipulation under anesthesia in about 70% of patients, though sample sizes were small and follow-up short.

Rauzi et al. (2022) retrospective cohort: 10 patients, 70% avoided manipulation; limited by design and sample size.

Elbow flexion contractures: For posttraumatic elbow stiffness, reviews found both static progressive splinting and dynamic splinting produced improvements in ROM in small studies; choice often depends on surgeon and patient preference with recommendations to continue until no further improvement (up to 12 months).

Veltman et al. (2015): SPS evaluated in 160 patients, dynamic splinting in 72; studies small and heterogeneous.

Knee arthrofibrosis and CPM/load-control devices: Studies of continuous passive motion (CPM), load-control, and displacement-control stretching devices in post-knee surgery patients reported improvements in ROM at short-term follow-up, but heterogeneity, measurement concerns, and inconsistent results limit definitive conclusions.

Equipment	Rental / Purchase Rule
Dynamic splinting systems (low-load prolonged-duration stretch devices; prefabricated and custom units for elbow, wrist, fingers, knee, ankle, toes)
Purchase — Custom dynamic splinting systems may be purchased when prefabricated units are ineffective due to limb size/shape or required load/material needs; policy states 'purchase' for dynamic splinting systems.

Device type	FDA classification / Rental or purchase notes
Mechanical stretching devices (examples: Dynasplint, Ultraflex, Pro-glide)
FDA classification: Class I devices, product code ION; 510(k) exempt. No rental or purchase rules specified in the FDA informational excerpt of the policy.

Documentation Requirements

Documentation Required

Submit medical records demonstrating joint contracture and adjunct-to-therapy use

Submit relevant medical records that demonstrate the member has an existing joint contracture and document how the device will be used as an adjunct to therapy (e.g., ROM measurements, prior therapy details, functional limitations); medical records may be required to assess coverage but do not guarantee payment.

Provide objective ROM measurements and clinical notes showing persistent contracture.
Include documentation of prior/concurrent physical therapy and justification for device as adjunctive treatment.

Documentation Required

Confirm member-specific benefit plan and mandates before coverage decision

Before ordering or approving equipment, verify the member-specific benefit plan document and any applicable federal or state mandates; the member plan governs coverage decisions and may differ from this clinical policy.

Check the member’s benefit plan for prior authorization, coverage limitations, and applicable mandates.
If there is a conflict, the member-specific benefit plan document controls.

OpenPayer

Mechanical Stretching Devices

Coverage Criteria

Coding

Provider Actions & Billing

Definitions

Medical Necessity

Rental and Purchase Rules

Replacement

Documentation Requirements

Not Covered

Background