The Starfish Procedure for Functional Recovery after Traumatic Partial Hand Amputation: A Case Report and Review of the Literature

Abstract

Background:

Partial hand amputations present significant reconstructive challenges because traditional reconstructive techniques and prosthetic devices often provide limited restoration of functional pinch and grip. The Starfish procedure is a novel reconstructive technique designed to optimize residual limb function and facilitate advanced prosthetic integration following complex partial hand amputation.

Methods:

A 30-year-old man sustained a traumatic partial hand amputation involving digits 2–5. Following initial wound stabilization and staged revision amputation, reconstruction was performed using regenerative peripheral nerve interfaces, full-thickness skin grafting, and the Starfish procedure. The intrinsic hand muscles were repositioned subcutaneously while preserving their neurovascular supply to create independent soft-tissue units suitable for myoelectric prosthetic control.

Results:

The patient achieved successful wound healing without postoperative complications. At 1-year follow-up, he demonstrated functional recovery, including intuitive and independent digit control with a myoelectric prosthesis, return to light-duty work, and the ability to perform activities of daily living. Restoration of tripod pinch and improved functional hand use appeared to exceed outcomes typically achieved with conventional reconstructive or prosthetic approaches.

Conclusions:

The Starfish procedure represents a promising reconstructive option for select patients with complex partial hand amputations. By combining innovative surgical reconstruction, targeted prosthetic integration, and multidisciplinary rehabilitation, this technique may improve functional outcomes and expand the reconstructive armamentarium available for severe hand injuries.

Takeaways

Question: What reconstructive options exist for patients with partial hand amputation when traditional methods and prosthetics fail to restore tripod pinch and functional grip?

Findings: The starfish procedure, applied in a young man with traumatic partial hand amputation, successfully restored tripod pinch and improved functional outcomes beyond what is typically achieved with conventional reconstructive or prosthetic approaches.

Meaning: This novel technique offers a reproducible method for maximizing functional recovery after partial hand amputation and may expand the reconstructive armamentarium for complex hand injuries.

INTRODUCTION

Partial hand amputations are among the most common traumatic injuries of the upper extremity, accounting for nearly 90% of amputations distal to the wrist.^1,2 These injuries often lead to life-altering consequences, significantly impairing a patient’s ability to perform activities of daily living and limiting their return to work.^3,4 Although replantation often yields improved outcomes in cases involving the thumb, attempts to replant multiple nonthumb digits typically result in suboptimal functional recovery, with minimal gains in grip strength, key pinch, and fine motor abilities.^5,6 Consequently, the management of partial hand amputations remains a complex challenge requiring individualized, multidisciplinary strategies.

Traditional reconstructive approaches include replantation, toe-to-hand transfer, and salvage operations.⁷ However, these methods often necessitate advanced microsurgical expertise, which is not universally available, and outcomes remain inconsistent.^8,9 Toe-to-hand transfers, for example, provide only partial recovery of hand strength, with grip strength reaching merely 26% and pinch strength, only 41%–70% of the contralateral uninjured hand.^6,8,10 Similarly, other salvage techniques may not restore sufficient functionality to meet the high demands of daily activities or occupational tasks.^9,11,12

Prosthetic options offer another avenue for rehabilitation. Among these, myoelectric prostheses have shown promise in enhancing function and usability, offering increased prehensile capabilities compared to passive or body-powered alternatives.^13,14 However, effective use of myoelectric prostheses in partial hand amputees has been limited by challenges such as insufficient muscle targets for signal detection, nonintuitive control mechanisms, and cross-talk between the small intrinsic muscles of the hand.^15,16

Recognizing these limitations, the starfish procedure was developed as a novel solution to improve the functional outcomes of myoelectric prostheses.¹⁷ By transferring intrinsic hand muscles to more superficial, subcutaneous locations while preserving their neurovascular pedicles, this technique generates distinct and reliable electromyographic (EMG) signals for each digit. These signals allow for intuitive, independent control of myoelectric prosthetic fingers, addressing many of the barriers faced by traditional prosthetic designs. The procedure does not require microsurgery or highly specialized training, making it accessible to a broader range of surgeons.

This report presents a case of a patient with a complex partial hand amputation managed through a combination of staged reconstruction, innovative surgical techniques, and advanced prosthetic integration, highlighting the role of the starfish procedure in achieving remarkable functional recovery.

CASE PRESENTATION

A 30-year-old man with no significant medical history sustained a mangled left-hand injury from a traumatic grinder accident. The injury resulted in amputations of the second through fifth digit at the level of the proximal phalanges, accompanied by extensive contamination and soft-tissue damage. On initial presentation, the patient underwent irrigation and debridement, followed by the application of negative-pressure wound therapy (NPWT) to stabilize the injury and prepare for subsequent interventions.

Radiographic imaging revealed amputations at the proximal phalanges with soft-tissue densities suggestive of foreign material (Fig. 1). Given the severity of the injury and shear mechanism, replantation was deemed unfeasible, and a staged surgical approach was undertaken to optimize the residual limb for future prosthetic integration. Four days after the initial intervention, repeat irrigation and debridement were performed to further prepare the wound bed. Two formal debridements were completed until the wound demonstrated healthy capillary bleeding without devitalized tissue. At the definitive operation, there was no clinical evidence of infection, and the wound bed had been maintained with a silver bilayer and silver-impregnated sponge under the wound vacuum-assisted closure. Although cultures were not clinically indicated, the field was deemed clean for reconstruction, and prophylactic broad-spectrum antibiotics were given due to the elevated infection risk associated with the prior Integra graft and its biofilm potential.

Fig. 1.

Preoperative anteroposterior radiographs of the left hand following a high-energy grinder injury demonstrate traumatic amputations of the second through fifth digits at the proximal phalanges with comminution, soft-tissue loss, and retained radiodense foreign material. The thumb remains intact, providing a stable column for functional reconstruction.

One week later, the patient underwent definitive revision amputation of the second through fifth metacarpals. To maximize functional recovery and optimize prosthetic control, the procedure combined the starfish and regenerative peripheral nerve interface (RPNI) techniques. The starfish component involved pedicled superficialization of viable intrinsic and extrinsic muscle bellies, repositioning them into a subdermal plane to enhance surface EMG signal detection and minimize cross-talk. Adjunctive RPNI constructs were then created by implanting selected transected nerve ends into free, denervated muscle grafts to prevent neuroma formation and expand the number of independent myoelectric signal sources (Table 1). Together, these steps established a stable, biologically active platform for future myoelectric prosthetic control.

Table 1.

Summary of Nerves Incorporated into RPNI Constructs, Including Transection Level, Indication, Graft Source and Dimensions, Inset Location, and Fixation

Nerve	Level	Indication	Muscle Graft Source	Approximate Graft Size	Inset Location	Fixation
Superficial radial sensory nerve	Distal forearm	Neuroma prevention and signal generation	EDC muscle slip	1 × 2 cm	Dorsal ray pocket	8-0 nylon
Dorsal ulnar sensory nerve	Wrist	Neuroma prevention	Free FCU muscle slip	1 × 1.5 cm	Ulnar ray pocket	8-0 nylon
Common digital nerve to ring finger	Distal palm	Additional signal source	FDS muscle slip	1 × 2 cm	Volar ray pocket	8-0 nylon

Mixed and motor-dominant nerves expanded myoelectric signal sources for prosthetic control, whereas sensory nerves were primarily included for neuroma prevention; all were implanted into free denervated muscle grafts and secured with epineurial sutures to facilitate reinnervation and stable EMG signals.

EDC, extensor digitorum communis; FCU, flexor carpi ulnaris; FDS, flexor digitorum superficialis.

To address the remaining soft-tissue defect, a dermal regeneration template (Integra graft) was applied, and NPWT was continued. Home health services provided vacuum-assisted closure changes every 3 days to maintain wound stability and hygiene. Early reconstruction allowed timely soft-tissue stabilization and repositioning of viable muscle bellies, whereas the tissues remained supple, well-perfused, and free of clinical infection.

Approximately 1 month later, the patient underwent full-thickness skin grafting (FTSG) to cover the residual wound (Fig. 2). A 9 cm × 3 cm graft harvested from the left groin was secured using fibrin glue and sutures, with NPWT applied to promote graft incorporation. Follow-up evaluations confirmed excellent graft integration with no signs of infection. By 3 months postinjury, the wound had fully healed, and the patient was cleared for prosthetic fitting (Fig. 3). During this time, the patient was educated on various prosthetic options and ultimately selected the myoelectric i-Limb Quantum prosthesis (Fig. 4).

Fig. 2.

Mangled left hand with complete amputation of the second through fifth digits at the distal and middle phalanges, leaving small proximal phalangeal remnants. After staged debridement and revision amputation, the wound was reconstructed with a full-thickness skin graft showing initial graft take and uniform perfusion.

Fig. 3.

Postoperative functional outcome following the starfish procedure: (A) dorsal view demonstrating well-healed soft tissues and preserved thumb mobility after partial hand reconstruction; (B) palmar view highlighting stable coverage and tripod pinch capability; and (C) integration of a myoelectric prosthesis allowing restoration of grip strength and fine motor function.

Fig. 4.

Myoelectric i-Limb Quantum prosthesis fitted following the starfish procedure. Images demonstrate the external appearance and functional digital articulation of the device, enabling independent control of reconstructed digits based on intuitive myoelectric signaling.

Rehabilitation focused on enhancing functional outcomes through occupational therapy 3 times weekly, consisting of both in-person sessions with advanced hand therapy specialists and virtual follow-ups. Therapy emphasized range of motion, strength, desensitization, and digital control. By 6 months, the patient demonstrated significant functional improvement, with the ability to engage in activities such as folding clothes, golfing, and fishing. However, minor strength deficits persisted in the reconstructed ring finger. The patient was also fitted with a backup static prosthesis for emergencies and instructed on prosthetic maintenance, including battery management.

The patient’s adherence to therapy contributed to steady progress in functional metrics. Two months after prosthetic fitting, his Disabilities of the Arm, Shoulder, and Hand score improved from 41 to 34 at 6 months. Range of motion increased to 125 degrees of flexion, with only minor deficits in extension. The patient resumed light-duty work with restrictions, including no lifting of more than 10 pounds, avoidance of water immersion, and precautions around high-voltage environments. An initial 10-lb lifting restriction was used for 6–8 weeks to protect the soft-tissue envelope and fixation; this was subsequently advanced to 20–30 lb in coordination with the prosthetics and device specifications.

At 1 year postoperatively, the patient demonstrates excellent recovery following left-hand revision amputation, RPNI, and FTSG; he reports no pain, numbness, or tingling, has been successfully fitted with a myoelectric prosthesis, and is actively engaging in functional rehabilitation without complications. (See Video 1 [online], which displays the independent myoelectric digital activation following the Starfish Procedure. Demonstration of isolated activation and extension-flexion of individual prosthetic digits, illustrating discrete electromyographic signal generation with minimal cross-talk after intrinsic muscle superficialization.) (See Video 2 [online], which displays the functional grasp and release with a myoelectric partial hand prosthesis. Coordinated multidigit flexion and extension during cylindrical/power grasp, demonstrating effective functional strength and intuitive prosthetic control.) (See Video 3 [online], which displays fine motor task performance. Demonstration of precision pinch involving selective finger flexion, highlighting restoration of fine motor control using the myoelectric partial hand prosthesis.) (See Video 4 [online], which displays the dynamic grasp sequencing and real-time prosthetic control. Continuous, volitional transitions between grasp patterns during simulated functional tasks, demonstrating sustained signal reliability and dynamic control of the prosthetic hand.)

Video 1. Independent myoelectric digital activation following the Starfish Procedure. Demonstration of isolated activation and extension-flexion of individual prosthetic digits, illustrating discrete electromyographic signal generation with minimal cross-talk after intrinsic muscle superficialization.

Download video file ^{(8MB, mp4)}

Video 2. Functional grasp and release with a myoelectric partial hand prosthesis. Coordinated multi-digit flexion and extension during cylindrical/power grasp and release of an object, demonstrating effective functional strength and intuitive prosthetic control.

Download video file ^{(17.2MB, mp4)}

Video 3. Tripod pinch and fine motor task performance. Demonstration of precision pinch involving thumb opposition and selective finger flexion, highlighting restoration of fine motor control using the myoelectric partial hand prosthesis.

Download video file ^{(11.5MB, mp4)}

Video 4. Dynamic grasp sequencing and real-time prosthetic control. Continuous, volitional transitions between grasp patterns during simulated functional tasks, demonstrating sustained signal reliability and dynamic control of the prosthetic hand.

Download video file ^{(1.4MB, mp4)}

Operative Technique

Through a dorsal approach, the residual hand was exposed, all nonviable tissue was excised, and the second through fifth metacarpals were circumferentially skeletonized on their periosteal envelopes. Approximately 3 cm of the distal metacarpals were resected to create uniform osseous platforms, taking care to preserve the dorsal interosseous and lumbrical neurovascular pedicles. The volar plates and flexor tendon sheaths of digits 2–5 were mobilized and rotated dorsally to augment soft-tissue bulk over the shortened metacarpal shafts.

A 0.035-inch K-wire was then used as a handheld drill to create paired dorsal cortical perforations along each metacarpal stump. These dual perforations established transosseous bone bridges that served as docking portals for soft-tissue fixation. For each ray, a strand of 3-0 FiberWire was passed through the interosseous canal of the corresponding dorsal interosseous muscle, delivered out through the proximal drill hole, re-introduced through the distal drill hole, and tied securely over the dorsal cortex. This transosseous looping pinioned the advanced muscle pedicle flush against the metacarpal stump, creating a stable myotatic anchor point. The dorsal interossei were then superficialized into a thin subdermal plane and oriented to maintain four discrete pedicled myotatic rays, each spaced to optimize surface EMG separation.

To limit muscular coalescence and preserve signal independence, the extensor digitorum communis tendon was isolated and interposed as a biologic septum between adjacent rays (Fig. 5). Transected digital nerves at risk for neuroma formation were then treated with RPNI constructs: each nerve was trimmed to healthy fascicles and implanted into a free denervated muscle graft (1 × 2 cm) harvested from expendable slips of extensor digitorum communis, flexor carpi ulnaris, or flexor digitorum superficialis using 8-0 nylon epineurial sutures. These RPNIs were inset in separate soft-tissue pockets adjacent to the superficialized rays to expand the number of independent myoelectric control sites.

Fig. 5.

Schematic of the Starfish Procedure following revision amputation of the third through fifth metacarpals demonstrating identification of the dorsal interosseous muscles (1), preservation on their native neurovascular pedicles (2), and distal advancement after metacarpal shortening (3). Volar plates and flexor tendon sheaths are rotated dorsally for soft-tissue bulk (4), paired dorsal cortical perforations are created for docking (5), and braided sutures secure each muscle belly through the interosseous canal to the metacarpal stump (6) with the extensor digitorum communis interposed as a biologic septum to reduce signal cross-talk (7).

The residual soft-tissue defect was resurfaced with a tailored dermal regeneration template and secured with NPWT to maintain a thin, conforming envelope suitable for prosthetic sensor integration. The configuration of pedicled myotatic rays and RPNIs was intentionally designed to facilitate postoperative EMG mapping, with expected findings including isolated motor unit action potentials for each ray or RPNI, minimal cross-talk, consistent voluntary recruitment, and maturation toward full interference patterns by 3-6 months. This construct establishes a stable, biologically active platform capable of generating multiple independent, high-fidelity myoelectric signals for advanced prosthetic control.

DISCUSSION

The starfish procedure is currently the only reported technique that allows for individual digital control of a myoelectric partial hand prosthesis.¹⁷ Its growing popularity is likely due to the highly intuitive and user-friendly control it provides, making it a preferred option for patients and clinicians alike. This principle of salvaging innervated muscles during any level amputation is critical; hence, the authors coin this the starfish principle.¹⁷

In a previous report by Grier et al, all patients successfully generated detectable myoelectric signals for each transferred muscle and utilized their myoelectric prostheses daily. Similarly, our patient demonstrated comparable outcomes.¹⁷ The intuitive nature of prosthesis control allows most patients to quickly master its use with minimal instruction. Occupational therapy remains valuable for strengthening, conditioning, and optimizing prosthetic utilization.^7,17 Native digital flexion and grasp are naturally initiated with metacarpophalangeal (MP) flexion, enabling the transferred intrinsic muscles to contract instinctively when patients think about closing their hand or fingers.^7,17 Although most patients achieve immediate and accurate prosthetic control, some benefit from learning to focus on performing MP flexion with interphalangeal (IP) extension to close their prosthesis.^7,17 Visualization exercises, such as imagining typing or playing the piano, activities that emphasize MP flexion over IP flexion, have proven particularly helpful in improving control.^7,17 Denduluri et al reported that patients who underwent the Starfish Procedure at their center used their myoelectric prostheses an average of 5.5 hours/d, 5–6 days/wk, for both household activities and work.⁷ Our patient has achieved a similar level of use, including engagement in outdoor manual labor. A minor limitation noted was the prosthesis battery life; however, with the availability of 2 batteries, the patient has been able to maintain continuous use throughout the day by switching batteries as needed.

The starfish procedure has specific indications and contraindications. Patients with amputations at or distal to the proximal IP joint generally retain enough digital length to maintain functional grasp and hand utility, often obviating the need for surgical reconstruction.^7,17 In such cases, these patients may benefit from simpler digital prostheses. However, when amputations occur between the MP and proximal IP joints, the functional capacity of the digit is significantly impaired, rendering it unable to contribute meaningfully to grasp.¹⁷ For prosthetic fitting, a minimal length of soft tissue-covered digit must remain to accommodate a ring for stabilization.¹⁷ This principle guides decisions on whether to salvage a digit for prosthetic use or proceed with a more proximal amputation and the starfish procedure.¹⁷

Candidates for the starfish procedure include patients with nonreplantable partial hand amputations at or distal to the midmetacarpal level who retain viable intrinsic hand musculature.¹⁷ Common causes leading to such interventions include trauma, deep soft-tissue infections, ischemia (eg, vasopressor-induced or vascular injury), chronic ischemia with gangrene, and limb-sparing oncologic resections.¹⁷ Contraindications include acute replantable digits, insufficient intrinsic musculature to generate the required myoelectric signals, ongoing infections in the residual limb, cognitive impairments that hinder prosthetic control, and neurological deficits such as ipsilateral brachial plexus or ulnar nerve palsies that leave the intrinsic muscles nonfunctional.¹⁷ A relative contraindication includes the absence of the first metacarpal, as key pinch would be jeopardized. The procedure can also be performed on a delayed basis.¹⁷ In such cases, amputations at or distal to the midmetacarpal level typically preserve intrinsic musculature with sufficient bulk for prosthetic control.¹⁷ If the functional viability of the interossei is uncertain due to residual metacarpal length or soft-tissue damage, formal EMG testing is conducted to assess their condition before proceeding with surgery.¹⁷ For delayed procedures, insurance authorization for a myoelectric partial hand prosthesis is typically secured in advance, as functional improvement relies on the integration of the prosthesis.¹⁷

Grier et al merit discussion on partial hand amputations with primary preference of primary closure if possible, and split-thickness skin graft as the second alternative to use the thinnest possible coverage. In our case, we opted for full-thickness skin graft for better aesthetic outcomes, less contraction during healing, and increased durability. The preference for thinner coverage, in split thickness skin graft, is aimed at facilitating prosthetic fitting and ensuring minimal interference with myoelectric signal detection. Thicker coverage, like FTSG or traditional flaps, might create challenges for prosthetic integration due to bulk, which can increase the distance between the underlying muscles and the myoelectric sensors. However, myoelectric sensors were not compromised, and this modification was considered a successful adaptation to the patient’s needs.

In our case, we utilized RPNIs as an alternative to targeted muscle reinnervation (TMR) for optimizing myoelectric prosthetic control. Although TMR redirects transected nerves to motor points, RPNI involves implanting residual nerves into free muscle grafts, offering a biologically stable environment to prevent neuroma formation and generate discrete EMG signals. RPNI is particularly advantageous in cases with limited or absent motor targets, allowing for flexible application without the extensive surgical requirements of TMR. Our outcomes were comparable to those reported with TMR in the starfish procedure, with reliable EMG signal generation, intuitive prosthetic control, and consistent daily use. The RPNI approach also reduced cross-talk, ensuring clear signal transmission for prosthetic functionality. Both techniques demonstrated similar success in facilitating rapid prosthesis adoption and improving functional outcomes.

In previous reports, complications associated with the starfish procedure have been rare. In a study by Grier et al, the most frequently observed issue among our patients has been wound dehiscence, typically resulting from insufficient soft-tissue coverage to securely close the distal edge. To mitigate this, authors prioritized preserving excess skin and subcutaneous tissue whenever feasible and have successfully utilized “spare parts” techniques, such as fillet flaps, to enhance closure. Another potential complication is damage to the neurovascular pedicle of the transferred interosseous muscles. Although the authors have not encountered this issue to date, it remains a theoretical risk. Surgeons performing the Starfish procedure must meticulously identify and preserve the neurovascular bundles during proximal dissection and separation of the interossei to avoid compromising muscle viability. Finally, when soft-tissue coverage is necessary, creating a thin, well-contoured envelope is essential. This approach not only facilitates optimal prosthetic fitting but also ensures that the transferred muscles remain close enough to the myoelectric sensors to allow effective signal detection. These precautions are critical for maximizing the functional outcomes of the procedure.

CONCLUSIONS

This case demonstrates the critical role of a multidisciplinary approach in managing devastating hand injuries. Advanced surgical techniques, including RPNI and staged soft-tissue reconstruction, combined with state-of-the-art prosthetic technology and structured rehabilitation, facilitated the patient’s return to a functional and independent lifestyle. Ongoing long-term monitoring will be essential to address potential prosthetic adjustments and ensure sustained recovery as the patient reintegrates into daily life and work activities.

DISCLOSURES

Mr. Hernandez discloses consulting fees from Axogen and Checkpoint Surgical. The other authors have no financial interest to declare in relation to the content of this article.

PATIENT CONSENT

Written informed consent was obtained from the patient for the publication of this case report and accompanying images.

ACKNOWLEDGMENT

Kolos K. Nagy completed illustrations for Figure 5.

ETHICAL APPROVAL

This case report was conducted in accordance with institutional guidelines. Written informed consent for treatment and publication of clinical details and images was obtained from the patient.