Bone transport combined with internal fixation in post-traumatic distal humerus defects and nonunions: retrospective analysis of 16 patients

Abstract

Background

This analysis aimed to assess the functional outcomes of patients with post-traumatic distal humerus defects and nonunions treated by bone transportation combined with internal fixation, containing two surgical techniques designed to enhance docking site union and functional recovery in critical distal humerus defects.

Methods

This retrospective study included 16 patients with post-traumatic distal humerus defects who underwent bone transportation combined with internal fixation between June 2017 and December 2023. Clinical records and consecutive X-ray images were reviewed to assess bone regeneration and alignment. The ASAMI criteria were applied to assess the bone and functional recovery, whereas the functional outcomes of the elbow joint were evaluated applying the Disabilities of the Arm, Shoulder, and Hand (DASH) score. Postoperative complications were classified using the Paley classification. Radial nerve function was systematically monitored preoperatively and at follow-up visits through comprehensive motor and sensory examination, with particular emphasis on delayed radial nerve palsy. Overall patient recovery, including range of motion (ROM) and functional improvement, was correlated with the DASH scores and postoperative complications. Statistical significance was defined as P < 0.05.

Results

The study included 16 patients ( mean age of 36.1 ± 8 years) with a mean humeral defect size of 5.6 ± 1.1 cm. The mean follow-up time was 22.1 ± 1.9 months, the average external fixation time (EFT) was 9.1 ± 1.4 months and the external fixation index (EFI) was 1.65 ± 0.11 months/cm. All humeral defects were successfully reconstructed. According to the ASAMI criteria, the treatment outcome was excellent in 6 cases, good in 8, and fair in 2. Elbow function significantly improved (p<0.01) post-operatively according to the DASH score. Mild extensional dysfunction was reported in 2 cases, and no radial nerve injuries or recurrent infections were observed. Pin tract infections were observed in 9 (56.26%) patients but were effectively managed with standardized dressing changes, without compromising the overall prognosis. The remaining patients achieved satisfactory clinical and functional recovery.

Conclusion

Bone transport combined with internal plate fixation effectively addresses post-traumatic distal humerus defects and nonunions by shortening external fixation time and lowering the incidence of docking site nonunion. This approach also eliminates the need for iliac bone grafting, thereby minimizing secondary trauma and enabling satisfactory joint function recovery.

Background

Distal critical humerus defects, typically resulting from post-traumatic nonunion, osteomyelitis-related bone loss, or high-energy open fractures, pose a substantial clinical challenge, particularly in the lower third of the shaft where structural integrity and joint function are both at risk [1]. These critical sized defects, typically defined as bone loss exceeding 50% of the circumference or more than twice the diameter of the humerus, often necessitate complex surgical intervention [2]. Traditional methods for addressing such extensive bone defects include autogenous bone grafting and vascularized bone grafting, acute-shortening and re-lengthening techniques [3], Masquelet technique [2, 4], and bone transport approaches like the Ilizarov technique [5]. Although these procedures have proven effectiveness in reconstructing bone defects and optimizing limb alignment, they involve significant drawbacks, including prolonged external fixation time, increased patient discomfort, and a heightened risk of complications like delayed union or nonunion at the docking site [6].

Managing distal humeral shaft defects remains difficult because of the unique anatomical structure and high functional demands of the humerus. The treatment strategies that combine bone transport with internal fixation have received attention as a possible approaches to these challenges [7]. This combined technique aims to shorten external fixation duration, lower the incidence of delayed union or nonunion at the docking site, enhance bone consolidation, and improve functional recovery of the limb. However, although studies have shown favorable outcomes, there is still limited comprehensive evaluation of long-term results, complications, and functional restoration in patients with distal humeral shaft defects treated using these methods [8].

Hence, this study aimed to evaluate the clinical outcomes and functional recovery associated with bone transport combined with internal fixation for post-traumatic distal humeral shaft defects and nonunions.

Methods

This study was approved by the hospital’s ethics committee, and informed consent was obtained from all participants. We retrospectively analyzed the clinical records and serial X-ray images of patients with segmental humeral shaft defects—defined in this study as cortical bone loss secondary to post-traumatic non-union, infection-related debridement, or acute open fractures—who received the treatment protocol between June 2017 and December 2023. Inclusion criterion: Post-traumatic distal humeral defects, defined as defects initially caused by trauma (including those complicated by osteomyelitis or nonunion), treated with bone transport and internal fixation. Exclusion criteria: Patients under 16 years of age; those with humeral defects secondary to tumor resection or congenital limb discrepancies; preoperative radial nerve injuries; severe soft-tissue defects; incomplete medical records; or poor compliance. The patient selection process is illustrated in Fig. 1, showing detailed exclusion reasons and final cohort size.

Fig. 1.

Flowchart of Patient Selection and Exclusion

The etiology of bone defects was categorized as follows: (1) Open fractures, based on intraoperative records and emergency documentation, with Gustilo-Anderson classification used when available; (2) Nonunion, defined as radiological and clinical absence of bone healing ≥ 6 months after the initial trauma; and (3) Post-traumatic osteomyelitis, diagnosed based on clinical symptoms, imaging, and microbiological evidence following trauma or surgery. Demographic data, details of the initial injury, previous treatments, antimicrobial use, and culture results of secretions were documented. Physical examination records included the assessment of shoulder and elbow range of motion (ROM) and the condition of the surrounding soft tissues. Inflammatory markers such as C-reactive protein (CRP), white blood cell (WBC) count, procalcitonin, and erythrocyte sedimentation rate (ESR) were recorded. The patients who suffered trauma-related infection received appropriate intravenous antibiotics for 2 weeks preoperatively, according to the sensitivity profile of the identified bacteria. Clinical records and consecutive X-ray images were reviewed to evaluate bone regeneration and alignment. The ASAMI criteria were applied to assess the bone and functional recovery, while functional outcomes of the elbow joint were evaluated using the Disabilities of the Arm, Shoulder, and Hand (DASH) score. Postoperative complications were evaluated using the Paley classification. Radial nerve function was systematically evaluated preoperatively and during follow-up visits through detailed examination for motor and sensory deficits, with specific attention to delayed radial nerve palsy. Patients’ overall recovery, including range of motion (ROM) and functional improvement, was analyzed in correlation with DASH scores and postoperative complications. Statistical significance was set at P < 0.05.

Surgical technique

All patients underwent thorough preoperative evaluation, including clinical examination and laboratory testing to assess inflammatory markers as previously mentioned, and the surgery was initiated only when these markers were normal or nearly normalized. Preoperative imaging, including X-rays and CTs, was used to evaluate the extent of the bone defect and the condition of the surrounding soft tissue. Patients with evidence of active infection were evaluated in consultation with the infectious disease team, and sensitive antibiotics were administered based on culture results. Radial nerve function was systematically examined preoperatively to ensure normal motor and sensory function.

Bone transport was performed using a monorail external fixator (Orthofix) in all cases. The fixator was aligned parallel to the longitudinal axis of the humerus to ensure correct alignment and stability. Proximal and distal fixation was achieved using three 4.5-mm Schanz screws in each segment, while 1–2 additional Schanz screws were placed in the transport segment. A minimally invasive osteotomy was performed at the proximal site using a Gigli saw to preserve blood supply and facilitate bone regeneration. Radial nerve protection was emphasized throughout the procedure, with meticulous dissection to avoid embedding or injury during resection and transport. Bone defect size (DS, cm) was carefully measured intra-operatively after the radical resection of necrotic, sclerotic, or infected (if there was so) bone tissue, and one of the surgical techniques listed below was selected based on the data.

Surgical technique 1

For defects < 5.0 cm (7 cases), acute shortening and internal fixation were performed at the defect site. After the docking site was compressed and securely fixed with a locking or anatomical plate, proximal osteotomy at the upper third of the humeral shaft was performed for bone transport. In patients with post-traumatic infection (PTI), the surgical area was thoroughly irrigated with hydrogen peroxide and povidone-iodine to minimize the risk of infection spread. A new sterile field was established, and all surgical instruments were replaced before proceeding with the proximal humeral osteotomy. Bone transportation commenced with a 12–14 days latency postoperatively at a rate of 1 mm/day (0.25 mm, 4 times daily) until the original humeral length was restored. (Fig. 2)

Fig. 2.

Schematic diagram of the protocol of acute-shortening and bone transportation combined with internal fixation(Surgical technique1). A Patient’s humorous with the distal humeral defect; B A unilateral frame(Orthofix) combined with an internal fixation plate is installed after acute-shortening of the defect site and proximal humeral osteotomy is carried out; C New callus generated after gradual bone transport, the longitude of the humerus is restored; D The external frame is removed after the bone lengthening period finished

Surgical technique 2

For humeral distal defects > 5.0 cm (9 cases), conventional bone transportation was performed in the first-stage surgery. After radical resection of pathological bone, the radial nerve epithelium was sutured to the lateral border of the biceps muscle using an 8 − 0 suture to prevent nerve embedding in the bone defect. A minimally invasive osteotomy was performed at the proximal humerus shaft, and bone transport was initiated 12–14 days postoperatively at the same distraction rate (0.25 mm, 4 times daily). Transport continued until the docking site was contacted, followed by locking or anatomical plate fixation on the docking site in a second-stage surgery. (Figure 3)

Fig. 3.

Schematic diagram of the protocol of humeral bone transportation followed by internal fixation at the docking site (Surgical technique 2). A Patient’s humorous with critical distal humeral defect; B A unilateral frame(Orthofix) is installed, and the proximal humeral osteotomy is carried out; C New callus generated after gradual bone transport, then the internal fixation plate is installed after the docking site connected; D, E After the bone lengthening period finished, the external frame is removed

Postoperative management

Postoperatively, bone regeneration in the distraction phase was monitored radiographically every 2–4 weeks. Consolidation was confirmed based on the radiographic presence of three-quarters of cortical bone formation. During the distraction phase, patients followed a standardized pin tract care regimen, including daily antiseptic cleansing and sterile dressing changes. Signs of infection, such as redness or swelling, were managed promptly to prevent complications.

Controlled range-of-motion (ROM) exercises for the shoulder and elbow began 7–10 days after the surgery. Functional activities were adjusted based on clinical and radiographic evaluations to ensure segmental stability.

Statistical analysis

DASH score data were analyzed using SPSS version 23.0 (Chicago, IL, USA). Continuous variables were presented as means and standard deviations. The independent samples t-test or Mann-Whitney U test was used to compare differences between the two groups of data pre- and pro-operative DASH scores, depending on the data distribution. Statistical significance was set at P < 0.05.

Results

This study included 16 patients with a mean age of 36.1 ± 8 years, comprising 12 males (75%) and 4 females (25%). Seven (43.75%) patients accepted Surgical technique 1, while the remaining nine (56.25%) accepted Surgical technique 2. The mean postoperative follow-up period was 21.1 ± 1.9 months. The mechanisms of initial humeral defects included direct trauma and post-traumatic nonunion with bone loss or osteomyelitis.

The mean bone transport length was 5.6 ± 1.1 cm. The mean external fixation time (EFT) was 9.1 ± 1.4 months, with a mean external fixation index (EFI) of 39.04 ± 3.32 days/cm. The distraction rate (DR) was 0.95 ± 0.02 mm/day. Bone union was achieved in 16 cases (100%), all docking sites were managed without additional intervention such as bone grafting or debridement. Compression and stable internal fixation alone were sufficient to achieve union in all cases. Pre-operational mean DASH score was 29.6 ± 5.4, and at the final follow-up, the mean DASH score was 28.75 ± 14.38, indicating statistically significant functional recovery of the upper extremity.

Two patients developed elbow joint extensional stiffness, which was addressed with a professional rehabilitation procedure. Nine cases of pin tract infection were reported, which were effectively managed by standard pin tract care and oral or systematic use of antibiotics, without compromising the overall treatment prognosis. None re-fracture, implant failure, and iatrogenic or delayed radial nerve palsy were reported. Axillary nerve integrity was assessed through clinical examination. No patients exhibited deltoid muscle atrophy or lateral shoulder hypoesthesia suggestive of axillary nerve injury.

At the final follow-up, the ASAMI score system (Table 3) was applied to evaluate bone and functional outcomes, there were 6 (37.5%) cases rated as excellent and 8 (50%) cases as good. The baseline and clinical dates are shown in Table 1. The DASH score was used to evaluate the functional outcomes of the affected elbow joint pre- and post-operatively, which improved with a significant statistical difference, p = 0.002 (p<0.05). (Table 2). The mean elbow flexion reached 128.6° ± 10.4°, and the mean extension deficit was 14.3° ± 5.7°, resulting in a flexion-extension arc of approximately 114.3° ± 9.8°. Forearm rotation was well preserved, with mean pronation and supination values of 77.1° ± 6.9° and 81.5° ± 7.2°, respectively.

Table 3.

Bone and functional results based on ASAMI scoring system and ROM

	Bone and Functional Results	Patients
Excellent	Union, no infection, deformity < 7°, limb-length discrepancy < 2.5 cm	6(37.5%)
Good	Union + any two of the following: absence of infection, deformity < 7°, limb-length discrepancy of < 2.5 cm	8(50%)
Fair	Union + only one of the following: absence of infection, deformity < 7°, limb-length discrepancy of < 2.5 cm	2(12.5%)
Poor	Non-union/re-fracture/union + infection + deformity > 7° + limb-length discrepancy > 2.5 cm	0(0%)

Table 1.

Baseline and clinical data

Number	Gender/Age(M/F)/years	Etiology of bone defect	DS (cm)	Latency(day)	Transportation time (d)	EFT (month)	EFI(month/cm)	DR(mm/day)	Follow up time(month)	Complication	Outcomes
1	F/32	Nonunion	4.5	12	47	7.5	1.67	0.96	20	-	Union
2	M/29	PTO	6.2	12	65	10.5	1.69	0.95	23	PTI	Union
3	M/26	Nonunion	4.5	13	48	8.5	1.89	0.94	21	PTI	Union
4	F/37	Nonunion	4.2	14	45	7.6	1.81	0.93	20	-	Union
5	M/45	Open fracture (IIIB)	6.8	12	72	11	1.62	0.94	23	PTI	Union
6	M/36	PTO	6.6	13	69	9.4	1.42	0.96	22	PTI	Union
7	M/37	Open fracture (IIIB)	4.5	13	49	7.8	1.73	0.92	24	-	Union
8	M/26	Nonunion	4.3	12	46	7.3	1.70	0.93	19	-	Union
9	F/29	PTO	6.9	12	72	10.4	1.51	0.96	22	JS, PTI	Union
10	M/30	Open fracture (IIIC)	4.2	13	46	7.4	1.76	0.91	20	-	Union
11	M/51	PTO	4.7	14	50	7.6	1.62	0.94	25	-	Union
12	M/42	Nonunion	6	12	61	9.4	1.57	0.98	24	PTI	Union
13	M/46	Nonunion	6.2	14	64	9.9	1.60	0.97	20	PTI	Union
14	F/45	PTO	6.3	12	66	10.2	1.62	0.95	23	PTI	Union
15	M/39	Nonunion	6.7	13	71	10.6	1.58	0.94	24	PTI	Union
16	M/27	PTO	6.8	12	70	11.2	1.65	0.97	24	JS	Union
Mean	36.1 ± 8		5.6 ± 1.1	12.7 ± 0.8	58.8 ± 10.9	9.1 ± 1.4	1.65 ± 0.11	0.95 ± 0.02	22.1 ± 1.9

PTO, post-traumatic osteomyelitis; DS, defect size; JS, joint stiffness; PTI, pin tract infection;

Table 2.

DASH score system

Pre-operative	Final follow-up
32	12
29	10
25	9
26	15
22	10
35	15
38	5
24	8
36	39
29	14
26	10
31	5
25	12
24	15
32	13
39	35
29.6 ± 5.4	14.2 ± 9.5
t = 7.40, p<0.001

Information on previous treatment, implant type, and surgical approach is summarized in Table 4. Among the 16 patients, 6 (37.5%) underwent prior debridement for post-traumatic osteomyelitis, 7 (43.8%) had failed internal fixation for nonunion, and 3 (18.7%) presented with acute bone loss following open fractures. Final fixation involved locking plates in 11 cases (68.8%) and anatomical medial-lateral plates in 5 cases (31.2%), using posterior (62.5%), lateral (25.0%), or anterolateral (12.5%) approaches.

Table 4.

Summary of previous treatment, implant type and surgical approach (n = 16)

Variable		Patients n (%)
Previous treatment
	Debridement only (PTO cases)	6 (37.5%)
	Prior internal fixation (Nonunion cases)	7 (43.8%)
	Acute bone loss (Open fracture cases)	3(18.7%)
Final internal fixation implant
	Locking plate	11 (68.8%)
	Anatomical medial-lateral plate	5 (31.2%)
Surgical approach (final fixation)
	Posterior	10 (62.5%)
	Lateral	4 (25.0%)
	Anterolateral	2 (12.5%)

Fig. 4.

Case 1: A 32-year-old female suffered from post-traumatic nonunion and re-fracture developed humeral defect was managed by the technique of bone transportation combined with internal fixation. a The patient suffered from a severe distal humeral fracture caused by high-energy trauma; b open reduction and internal fixation surgery was performed 4 days after the accident; c, d it developed to a nonunion and implant failure 4 months after the initial surgery; e removing of the original internal fixation devices and the thorough debridement resulted in a 4.5 cm humeral defect, the patient underwent Surgical Technique 1; f. X-ray images at 2 months after the surgery show restoration of limb longitude without axial deviation or poor mineralization; g X-ray image at 7 months after the surgery, before the removal of the external fixator; h X-ray image at one year after removing the external fixator; i last follow-up examinations shows excellent functional recovery of the elbow

Fig. 5.

Case 2: A 34-year-old male who underwent the protocol with the Surgical technique 2; a The patient suffered a severe open fracture in the distal humeral shaft due to high-energy trauma; b Underwent open reduction and external fixation, which developed into osteomyelitis; c after thorough debridement, the humeral defect was 6.6 cm and the Surgical technique two was applied; d X-ray image at 1month since the distraction; e X-ray image at 8month after the surgery shows contact at the docking site and good mineralization; f X-ray at one year after the external fixator was removed and the anatomical plates were implanted

Discussion

Humeral bone defects are relatively rare and complicated compared to lower extremity defects [9], often accompanied by nerve (particularly radial nerve) and soft tissue injuries, requiring individualized treatment strategies [10]. Conventional treatment methods include acute shortening and re-lengthening, vascularized fibula grafting, the Masquelet technique, and bone transport (monofocal or multifocal) [4, 11–13]. Bone transportation is a common and effective treatment for distal humeral shaft defects [14], allowing for bone defect repair while minimizing further damage to surrounding nerves and soft tissues. However, it still faces complications such as pin tract infection, docking site nonunion, and joint dysfunction due to prolonged external fixation [3]. To shorten the duration of external fixation and reduce complications, this study innovatively combines internal fixation at the docking site with bone transport and asses its clinical and functional effectiveness and advantages.

A surgical strategy of acute shortening at the bone defect site followed by internal fixation and limb lengthening (Surgical technique 1) was employed in seven patients in this study. In trauma-related bone defects, especially those involving prior infection or compromised soft tissue, internal fixation in the initial stage was avoided to minimize the risk of implant-related infection. External fixation offered sufficient mechanical stability and a safer biological environment during distraction, with internal fixation performed secondarily once local conditions improved. Although the overall EFI remained within the range commonly reported in the literature, the use of internal fixation at the docking site may have contributed to limiting the duration of external fixation and preventing docking site nonunion, complications frequently observed in traditional bone transport protocols without internal support [15]. In conventional methods, external fixation is typically required for up to five to six additional months to ensure adequate bone consolidation [16]. Literature has pointed out that sclerosis “fibrous cap” and resorption can happen at both side of defect size [17], which is hard to prevent, increases the incidence of nonunion and prolongs external fixation time, leading to poor healing. The shortening bone defect segment with the internal fixation technique used in this study avoids this issue, allowing the external fixator to be removed once the consolidation completed without concerns of docking site union. This strategy promotes early functional activities which is essential for recovery of shoulder and elbow functions [18]. All cases eventually achieved bone healing without nonunion at the docking site, further proving the efficacy of the surgical strategy.

Acute limb shortening for bone defects may lead to adequate or delayed circulations disorder, nerve palsy, muscle strength compromises or atrophy, thus is not recommended for excessive defects [3, 19]. To minimize the occurrence of these complications, we implemented a traditional osteotomy and transportation with internal fixation at the docking site (Surgical strategy 2) for the treatment of humeral defects>5.0 cm in this study. Notably, the 5.0 cm threshold has been supported by both published studies and our clinical experience as an acceptable upper limit for safe acute shortening in adult humeral shaft reconstruction. Studies [20, 21] suggested that ASR(acute shortening and re-lengthening)technique slightly improves EFI compared to the bone transportation but not statistically different, while the latter had higher incidence of complications. The advantage of our strategy combining bone transportation lies in its ability to avoid muscle weakness, while the downside is the requirement for two-stage surgery. However, the patients had good recovery of elbow joint function postoperatively, with no significant limitations in flexion and extension. Two cases developed elbow extension dysfunction, particularly among those who had prolonged external fixator use. We believe this is related to a combination of factors, including elongation stimulation, second-stage internal fixation, and prolonged external fixation time, which may have contributed to brachialis muscle adhesion and soft tissue contracture. Additionally, both cases had docking sites located at the distal third of the humerus, in close proximity to the olecranon. This anatomical relationship may have further limited elbow extension due to capsular contracture and periarticular adhesion around the joint.

During surgical procedures, protection of the radial nerve is essential [22], especially for patients without limb shortening. The radial nerve crosses the humeral mid-distal section, and previous literature [23] has reported cases where the radial nerve became entrapped and adhered to the elongation segment, resulting in delayed radial nerve palsy. In this study, no radial nerve injury or delayed palsy was observed in any case, due to careful exposure of the radial nerve in the mid-distal section during surgery, ensuring it was fixed under the muscle fascia, preventing contact with the elongation segment and subsequent entrapment. Furthermore, active functional exercises of the elbow joint during distraction were one of the key points to prevent the complication. In contrast to the lower limb bone transportation, long plates are not recommended for internal fixation (such as the MIPO technique) due to the elevated risk of radial nerve injury. This critical anatomical consideration differentiates upper extremity reconstruction from lower limb orthopedic interventions, necessitating distinct surgical approaches for humeral distraction osteogenesis. In the 16 cases of this study, special attention was given to protecting the radial nerve, ensuring it did not encounter the distraction area. Follow-up results showed no symptoms of radial nerve injury or delayed palsy.

For humeral bone defects less than 4 cm, literature studies suggest that ASR technique is more appropriate [24]. In our study, for defects less than 5 cm, we preferred the shortening and lengthening strategy and we recommended bone transportation protocol followed by internal fixation to the cases with defects >5 cm. Additionally, the selection of internal fixation devices for the humeral shaft is an important consideration in treatment strategies. Considering that long plates might damage the radial nerve, we suggest minimizing the number of surgeries to reduce secondary trauma and the risk of radial nerve injury. The bone transport technique without limb shortening avoids weakening of upper arm muscle strength and allow for better recovery of elbow joint function. While this method may increase the risk of delayed radial nerve palsy, such complications were not observed in our study. Compared with lower extremity bone transportation, patients undergoing humeral bone transportation applying our strategies generally showed better compliance, and because the upper limb is non-weight bearing and less prone to irritation, the risk of pin tract infection is relatively low. This further supports the safety and feasibility of upper limb bone lengthening treatment.

In bone transport treatment without a limb shortening procedure, the upper limb muscles can maintain good tension and function, supporting the recovery of elbow joint motion and strength. This helps avoid postoperative muscle strength decline, as the tension and coordination of the proximal humeral muscles are preserved. In contrast, shortening leads to local muscle contraction, limiting the range of motion and potentially weakening strength or causing dysfunction. Shortening may also result in abnormal changes in the tendons, affecting the normal function of the upper limb. For these reasons, we tend to recommend bone transportation treatment without a limb shortening to avoid postoperative muscle strength reduction and promote the recovery of upper limb muscles and elbow joint function.

The anatomical differences between the mid-shaft and distal segments of the humerus [25] contribute to challenges in docking site union. The mid-shaft exhibits a nearly circular cross-section, whereas the distal segment transitions to a flattened triangular shape. During the union, the mismatch in geometry at the docking site (Fig. 6.) results in incomplete alignment of the proximal and distal cross-sections, failing to achieve contact upon complete docking. This ineffective interface prolongs healing time but also elevates the risk of nonunion. The bone transport combined with internal fixation therapeutic approach adopted in this study represents a bold innovative and effective treatment strategy developed and implemented to reduce the risk of various complications including nonunion at the docking site, axial deviation, and impaired mineralization, among others.

Fig. 6.

Humeral cross-sectional geometry at mid-shaft and distal segments

Conclusion

Bone transport combined with internal fixation is an effective and reliable strategy in post-traumatic distal humeral defects and nonunion. This approach reduces complications such as delayed union, nonunion, and joint stiffness while promoting satisfactory bone regeneration and functional recovery. Two strategies were explored: acute shortening and internal fixation followed by bone transportation, and traditional bone transportation with internal fixation at the docking site. Both demonstrated favorable clinical and functional outcomes.

Author contributions

XK, AS, XM, and AY developed the research questions and scope of the study. XK and AS conducted preoperative and postoperative data screening and data charting. XK, AA and YH drafted the manuscript and prepared tables, and figures with XM’s contribution. XK, XM, and YX developed the literature search strategies in collaboration with the other authors. XK, YX, and AY contributed to the organization, analysis, and interpretation of the results. All authors read and approved the final manuscript.

Funding

This work was supported by the Central Guiding Local Science and Technology Development Special Fund Project [grant number ZYYD2022A03, 2022], and the Tianshan Talent Technology Innovation Leading Talent - High-Level Leading Talent Project [grant number 2022TSYCLJ0026, 2022].

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

This retrospective study was approved by the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University and carried out by the ethical standards set out in the Helsinki Declaration. Informed consent was received from all participants.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Clinical trial number

Not applicable.