Composite dorsal wrist soft tissue defects are a major challenge in the clinical treatment of hand surgery, and their etiology includes high-energy trauma (such as machine twist injury and traffic accident injury), wounds after tumor resection, and severe infection (1). Such injuries often simultaneously involve the skin, subcutaneous tissue, extensor tendon, and wrist joint capsule, leading to complex anatomical structure damage and dysfunction (2). Traditional repair methods, such as free skin grafting or local random flaps, are difficult to meet the requirements of functional reconstruction, and postoperative complications such as tendon adhesion, joint stiffness, and flap necrosis often occur, which seriously affect the hand function and quality of life of patients (3, 4).

In the repair strategy of dorsal wrist defect, an ideal treatment scheme should meet the following three key objectives simultaneously: provide reliable soft tissue coverage to protect deep structures; reconstruct the extensor tendon system to restore the range of motion of the wrist; and perverse donor site function to repair defects in this area because of the advantages of using the posterior interosseous artery as a constant blood supply, its anatomical location adjacent to the dorsal wrist, hidden donor area, and carrying sensory nerve. Nevertheless, a simple flap graft can only solve the problem of soft tissue coverage. For patients with extensor tendon defects, two-stage tendon grafting or tendon transposition is still required, which not only prolongs the treatment cycle but also may lead to poor functional recovery due to scar adhesion (5, 6).

In recent years, with the development of microsurgical technology and rehabilitation medicine, the strategy of one-stage combined reconstruction has been received increasing attention (7). Scholars worldwide have attempted to perform autologous tendon grafts simultaneously to achieve simultaneous repair of soft tissue and function through a single operation (8). For instance, a report applied free dorsal interosseous flap (DIOF) combined with a palmaris longus tendon graft to repair a case of dorsal wrist defects and demonstrated excellent early functional recovery (9). The removal of free skin flaps only requires sacrificing a portion of the superficial fascia of the forearm, resulting in minimal impact on the motor function of the donor area. However, for pedicled skin flaps, the integrity of the vascular pedicle needs to be maintained, which may lead to excessive skin tension or sensory disorders in the donor area. In addition, free flaps can be independently designed in terms of shape and size, and are suitable for irregular defects (such as complex defects involving tendon or bone exposure). The free flaps can carry sensory nerves and be anastomosed with the recipient nerve, thereby promoting the recovery of sensation. However, most existing reports focus on the description of surgical techniques, and there is still a lack of systematic evaluation of the biomechanical adaptability of tendon grafts, long-term follow-up of flap sensory recovery, and impact of standardized rehabilitation programs.

Furthermore, the standardization of wrist function evaluation systems also deserves attention (10). Currently, commonly applied clinical evaluation indicators include objective parameters such as total active motion (TAM, back extension + palm flexion), grip strength recovery rate, and subjective function scales such as Disabilities of the Arm, Shoulder and Hand (DASH) scores (11). Nevertheless, different studies have different definitions of “excellent functional recovery”. For example, some scholars consider TAM ≥ 75% of the normal value as the standard (12), while others require a grip strength recovery rate of more than 80% (13). This heterogeneity makes it difficult to directly compare research results directly and hinders the formation of a clinical consensus. Traditional assessment lacks a systematic evaluation of tissue healing quality, hemodynamic changes, and patients’ subjective experience. The existing literature has the following limitations in evaluating the curative effect: the tendon healing process lacks objective quantitative indicators; conventional clinical examination is difficult to accurately evaluate microstructural changes in the transplanted tendon, while histological examination is invasive. Blood flow monitoring after flap surgery mostly remains in qualitative observation, lacking quantitative analysis data (14). Furthermore, the application of patient-reported outcomes (PROs) in surgical evaluation has not received sufficient attention (15).

This study aimed to elucidate the clinical effect of free DIOF combined with tendon graft on function recovery in one-stage reconstruction of composite dorsal wrist soft tissue defects.

This study systematically analyzed the clinical data of 28 patients who underwent a single procedure of DIOF combined with autologous tendon transplantation to repair complex dorsal wrist defects, and achieved remarkable results in flap survival rate, functional recovery, and sensory reconstruction. Compared to previous studies (21), our research not only confirmed the reliability of this technique but also achieved a technological innovation and theoretical breakthrough in multiple aspects.

In terms of flap survival, the success rate in this study (96.4%) was 5%–10% higher than that of the traditional method. This achievement is attributed to three key technical improvements: high-frequency ultrasound accurately located the puncture point of the posterior interosseous artery before the operation, which makes flap design more individualized; during the vascular anastomosis process, a double venous return channel was established, effectively reducing the incidence of venous crisis; for cases with infectious defects, innovatively combining antibiotic bone cement with the flap coverage achieved the dual goals of infection control and vascular reconstruction. Notably, these 3 cases of diabetic ulcers were successfully repaired through this comprehensive treatment plan, which provides a new approach for treatment of chronic wounds.

Function recovery is a core observation indicator in this study. This study demonstrated that single-stage tendon graft was significantly superior to the traditional two-stage surgery in multiple aspects. In terms of motor function, the TAM reached (112.5 ± 11.8)° after the operation, and the range of palmar flexion motion was (67.2 ± 8.4)°, which was close to the normal level. This was mainly due to the use of the 6-strand Tsuge method to strengthen tendon suture strength during the operation and gradual rehabilitation training under the protection of a brace in the early postoperative period (22). In terms of muscle strength recovery, the grip strength recovery rate (83.7%) markedly improved the quality of life of patients. Through a multi-dimensional evaluation of the Mayo scoring system, the excellent and good rates showed a significant positive correlation with tendon sliding distance and grip strength recovery, which provided an objective basis for the prediction of postoperative function.

Sensory reconstruction is a crucial innovation in this study. Through precise neurorrhaphy technique, 89.3% of cases reached a sensory grade above S3⁺, and 64.3% of them had two-point discrimination less than 10 mm, which was far more than previously reported (23–25). In particular, we noticed that the tactile recovery time in the anastomosis group was 3 weeks earlier than that in the non-anastomosis group, and the final sensory level was generally improved by 1–2 levels. In six cases of infection, the modified method of preserving continuity of the nerve adventitia still achieved satisfactory sensory recovery, which provides an important reference for nerve repair in high-risk wounds.

The application of high-frequency ultrasound improved tendon healing evaluation from simple “survival or not” to “quality evaluation”. The excellent healing rate of 92.9% confirmed that the transplanted tendon had good biological integration, which was closely related to the technical points of preserving tissue around the tendon during the operation. It is worth noting that both cases of poor healing were infected, suggesting that such patients may requires a longer braking time. Flap blood flow was quantitatively evaluated using laser Doppler. This rule provides an objective basis for clinical observations (26). One case of abnormal perfusion detected by real-time monitoring was treated promptly to avoid flap necrosis. Traditionally, TAM recovery represents good function, whereas stability tests have demonstrated that about 10% of cases have potential instability (27). Biomechanical analysis revealed a significant correlation with the quality of ligament repair. This suggests that more attention should be paid to the reconstruction of the ligament structure in future surgeries. The satisfaction score of 9.2 points verified the value of surgery from the perspective of patients. It is particularly noteworthy that although the appearance score was relatively low (8.7 points), the functional recovery and daily activity scores were more than 9 points, reflecting that patients pay more attention to function than beauty.

In comparison with similar studies at home and abroad (28, 29), the innovation of this research is majorly reflected in three aspects: in terms of surgical strategy, traditional staged treatment is optimized as “debridement reconstruction rehabilitation” integrated scheme; in evaluation system, a multi-dimensional evaluation model including motor function, muscle strength recovery, and sensory reconstruction was established for the first time; on rehabilitation program, a staged training protocol based on biomechanical properties was developed. These innovations depict the remarkable advantages of health economics.

This study also has some limitations. The small sample size may affect statistical efficacy, especially in the bone defect subgroup with only four cases, which makes it difficultly to conduct an in-depth subgroup analysis. The long-term reconstruction of the implanted tendon still needs to be observed for a longer period. Moreover, the lack of a randomized controlled design makes us more cautious in terms of causal inference. These limitations also point to directions for future research: developing a preoperative planning system based on deep learning, exploring new biomaterial alternatives, and conducting multicenter randomized controlled trials.

The DIOF combined with tendon graft is a reliable treatment for composite dorsal wrist defects. Its advantages in anatomical reconstruction, functional recovery, and sensory reconstruction make it particularly suitable for repairing complex defects caused by trauma and infection. With the continuous optimization of technology and the accumulation of evidence-based data, this surgical approach is expected to become one of the standard treatments for composite dorsal wrist defects.