A clinical study of percutaneous Kirschner wire fixation in pediatric supracondylar humeral fractures with medial column impaction: surgical technique and outcomes

Abstract

Background

This study aims to introduce a surgical technique using percutaneous Kirschner wire fixation for pediatric supracondylar humeral fractures with medial column impaction.

Methods

A retrospective analysis was conducted on 46 patients diagnosed with supracondylar humeral fractures with medial column impaction who underwent treatment at a children’s hospital, from January 2022 to January 2024. Among these patients, 20 received percutaneous K-wire fixation, while 26 underwent conservative treatment. Fracture healing time and complications were recorded. The carrying angle (CA) and Baumann angle (BA) of the affected elbow joint were assessed preoperatively, immediately after surgery, and at 3 months postoperatively. Elbow range of motion was measured and compared at the final follow-up. Additionally, elbow function was evaluated using Mayo Elbow Performance Score (MEPS).

Results

All 46 patients completed follow-up, with durations ranging from 4 to 10 months. Fracture healing times were similar between the two groups, averaging 27.60 ± 1.85 days in surgical group and 27.85 ± 2.33 days in conservative treatment group. Postoperative complication rates were 5% and 7.7%, respectively. No statistically significant difference in the preoperative BA (P > 0.05). However, significant differences were observed in terms of immediate postoperative BA, BA at 3-month follow-up, and CA at 3-month follow-up(P < 0.05). At the final follow-up, elbow joint range of motion was similar( P > 0.01). However, MEPS demonstrated significantly better functional outcomes in the surgical group ( P < 0.05).

Conclusion

Percutaneous Kirschner wire fixation is effective in treating this distinctive fracture subtype, providing superior radiographic alignment and comparable cosmetic outcomes.

Background

Supracondylar humeral fractures are among the most common pediatric fractures encountered in orthopedic practice [1, 2]. A particular subtype, initially described by De Boeck, involves medial column impaction and collapse, typically with intact lateral cortical continuity and mild anterior-posterior displacement or angulation [3]. Although conservative management, including closed reduction and cast immobilization, is usually adequate for pediatric supracondylar fractures without significant displacement [4], several studies advocate for early intervention with percutaneous Kirschner wire (K-wire) fixation in cases involving medial column impaction [5–7]. The occurrence of medial column impaction following the reduction of severely displaced supracondylar humeral fractures is frequently discussed in the literature. It is considered an undesirable reduction position, as it may alter the Baumann angle and lead to post-traumatic cubitus varus [8, 9]. While significant displacement and medial column collapse have been extensively studied and documented, mild medial impaction is often under-recognized. This subtle pattern of impaction often leads to complications such as cubitus varus or limb misalignment in the long term. Despite increased awareness of these issues, the clinical management of mild medial impaction fractures remains insufficiently defined in current literature. Consequently, the necessity of surgical intervention and the most effective fixation techniques remain unclear, warranting further investigation. The aim of this study is to evaluate the clinical effectiveness and reliability of percutaneous K-wire fixation compared to closed reduction and plaster immobilization, evaluating outcomes such as the carrying angle (CA), Baumann angle (BA), elbow joint range of motion, Mayo Elbow Performance Scores (MEPS), and complication rates in pediatric patients presenting with medial column impaction supracondylar fractures. The findings from this study are expected to provide clinicians with evidence-based guidelines for treatment selection, ultimately contributing to improved functional and cosmetic outcomes in children affected by this distinctive fracture subtype.

Methods

Inclusion criteria

(1) Confirmed diagnosis of supracondylar humeral fracture with medial column impaction: (1) Anteroposterior X-ray: Medial cortical compression with > 2 mm displacement. Lateral cortex intact or with slight displacement. Lateral X-ray: No displacement or mild angulation. (2) Physical examination: Varus deformity > 0°. (2)Age < 14 years; (3) No previous history of fracture in the affected limb; (4) Interval from injury to surgery within 1 week.

Exclusion criteria

(1) Open fractures; (2) Pathological fractures; (3) Concurrent fractures in other locations of the upper limb; (4) Concomitant ulnar nerve injury; (5) Congenital deformities of the upper limb; (6) Mental disorders precluding compliance with clinical assessment.

Study population

All eligible patients and their caregivers were informed in detail about the benefits and risks of both surgical and conservative treatments. Final treatment decisions were made based on parental preference after shared decision-making. Thus, group allocation was not randomized but reflects real-world clinical practices.

This retrospective study analyzed clinical data from 46 pediatric patients treated for supracondylar humeral fractures with medial column impaction at a children’s hospital between January 2022 and January 2024. Twenty patients underwent percutaneous Kirschner wire fixation (surgical group; 12 males and 8 females, mean age 8.35 ± 2.18 years, mean preoperative BA 79.35° ± 2.38°). Twenty-six patients received conservative treatment with closed reduction and cast immobilization (conservative group; 17 males and 9 females, mean age 8.23 ± 1.80 years, mean pre-treatment BA 78.59° ± 1.96°). No significant differences were observed between groups regarding these baseline characteristics. This study was approved by the Medical Ethics Committee of Anhui Province Children’s Hospital (EYLL-2023-024).

Treatment methods

Surgical group

All surgical procedures were performed under combined intravenous-inhalation general anesthesia with patients positioned supine. A C-arm fluoroscopy unit (Philips Medical Systems, Netherlands) was placed with the receiver inverted beneath the operating table. Initially, the patient’s unaffected elbow was positioned onto the receiver, and fluoroscopy was performed to measure and document the normal BA. This was performed with informed parental consent, using single-shot low-dose exposure. Subsequently, the receiver was moved horizontally to the affected shoulder area, and the injured limb was fully positioned onto the receiver, effectively serving as the surgical Table [10]. Following routine skin preparation and sterile draping, elbow joint deformities, including anterior-posterior displacement and angulation, were corrected first through elbow-flexion maneuvers. The affected limb was then externally rotated so the medial side of the elbow faced upward. The elbow joint was gradually extended to approximately 30°. The medial epicondyle was carefully palpated posteriorly and medially along the transverse elbow crease using the surgeon’s left thumb. In cases of significant swelling, additional thumb pressure was applied to displace soft tissues posteriorly, allowing clear identification of the medial epicondyle. Once the medial epicondyle was localized, it was gently displaced posteriorly and medially using thumb pressure, while simultaneously protecting the ulnar nerve and the ulnar groove throughout the procedure. A 2.0 mm Kirschner wire (K-wire), held in an electric drill by the surgeon’s right hand, was then inserted from the medial epicondyle at approximately a 45° angle relative to the longitudinal axis of the humerus. During wire insertion, close attention was paid to any involuntary movement of the patient’s ring or little finger, indicative of potential ulnar nerve irritation. If such movement occurred, the K-wire was repositioned. After the K-wire reached the opposite cortex, drilling was halted, and the wire was retracted slightly (approximately 0.5 cm). At this stage, using the medial epicondyle as a fulcrum, lateral pressure was applied using the surgeon’s thumb along with the partially inserted K-wire to maximally correct medial column compression. Once firm resistance was encountered, the K-wire was advanced completely through the opposite cortex to secure stable fixation. Fluoroscopy was repeated to confirm adequate correction of medial column impaction. Subsequently, the elbow was rotated anteriorly and flexed maximally, and two additional K-wires were inserted from the lateral epicondyle, placed parallel and divergent from each other. Post-fixation fluoroscopy was used again to record the corrected BA and CA of the affected elbow. After fixation was confirmed radiographically, the pin entry sites were disinfected, and the exposed ends of the K-wires were bent, trimmed, and left external to the skin. Sterile gauze strips and sterile dressings were applied around the pins, followed by placement of a full-length upper-limb cast splint with the elbow maintained in a neutral position.(Fig. 1).

Fig. 1.

(a, b) The medial epicondyle was palpated and the ulnar nerve was gently displaced posteriorly by the surgeon’s thumb. A K-wire was inserted into the medial epicondyle at approximately 45° relative to the humeral shaft axis until it reached the opposite cortex, then withdrawn slightly (approximately 0.5 cm). The medial epicondyle was subsequently displaced laterally using combined pressure from the thumb and Kirschner wire, and the wire was advanced securely into the opposite cortex once optimal reduction was achieved. (c, d) Intraoperative anteroposterior (AP) fluoroscopic views during wire insertion

Postoperatively, symptomatic treatments such as hemostasis and swelling control were administered. Patients’ conditions were closely monitored, particularly focusing on the cleanliness of the dressing, limb swelling, and sensory-motor function of the ring and little fingers. At discharge, caregivers received instructions regarding keeping dressings dry, monitoring cast odor, and assisting the child in performing gentle functional exercises such as fist-making movements. Patients returned for follow-up at 4 weeks postoperatively to radiographically evaluate fracture healing and determine the appropriate timing for cast removal and K-wire extraction. After immobilization was removed, patients were encouraged to engage in active elbow flexion-extension exercises. Another follow-up evaluation was scheduled 3 months postoperatively to comprehensively assess fracture union, elbow joint function, and cosmetic outcomes.(Fig. 2).

Fig. 2.

(a) Pediatric patient admitted with swelling and pain of the left elbow one day after injury. AP and lateral radiographs at admission revealed a supracondylar fracture of the left humerus with significant medial impaction but minimal lateral and anterior-posterior displacement. (b) Immediate postoperative AP and lateral radiographs after percutaneous K-wire fixation under general anesthesia with plaster immobilization demonstrated anatomical reduction and satisfactory restoration of BA and CA. (c) Radiographs at 3-month follow-up showing satisfactory fracture healing with maintained BA and CA correction. (d) At the final follow-up, the patient’s left elbow exhibited full functional recovery and cosmetic symmetry compared to the unaffected side

Conservative group

Closed reduction was performed by two surgeons applying counter-traction, followed by manual manipulation to correct medial column impaction through firm outward and downward pressure applied to the medial epicondyle. Subsequently, the affected limb was immobilized using a full-length upper limb plaster splint with the elbow in a neutral position. Patients underwent clinical follow-up at four weeks post-reduction, with cast removal determined by radiographic evidence of fracture healing. After cast removal, elbow joint functional rehabilitation exercises and subsequent follow-up assessments were performed in the same manner as described for the surgical group.((Fig. 3).

Fig. 3.

(a) Pediatric patient admitted with swelling and pain in the left elbow five hours post-injury. Initial AP and lateral radiographs revealed a supracondylar fracture of the left humerus with significant medial column impaction but minimal anterior-posterior displacement. (b) Radiographs obtained after 4 weeks of conservative treatment (closed reduction and plaster immobilization) showed satisfactory fracture healing with mild residual medial column impaction. (c) At the final follow-up, full-length anteroposterior radiographs of the left upper extremity showed a CA of -4.6° and a BA of 80.6°. Clinically evident cubitus varus deformity of the affected elbow was clearly visible upon visual comparison with the contralateral limb

Outcome measures

The BA and CA of the affected elbow joint were measured and compared between the two groups preoperatively, immediately postoperatively, and at 3 months postoperatively. Additionally, elbow joint range of motion at the final follow-up was assessed and compared between the groups. Fracture healing progress and the incidence of postoperative complications were recorded throughout the follow-up period. At the final follow-up, elbow function was evaluated using MEPS [11]. The percentages of patients achieving excellent and good outcomes were calculated for each group.

Statistical analysis

All statistical analyses were performed using SPSS statistical software (version 26.0, IBM Corp., Armonk, NY, USA). Measurement data conforming to normal distribution with homogeneity of variance were presented as mean ± standard deviation (x ± s) and analyzed using paired-sample t-tests. Data that did not follow a normal distribution or exhibited unequal variance were presented as median with interquartile range [M (Q1, Q3)] and analyzed using the Wilcoxon signed-rank test. Differences were considered statistically significant at a P-value < 0.05.

Results

All 46 patients completed postoperative follow-up, with an average duration of 5.42 ± 1.21 months (range: 4–10 months). Fracture healing times were 27.60 ± 1.85 days in the surgical group and 27.85 ± 2.33 days in the conservative treatment group. Postoperative complication rates were 5% in the surgical group and 7.7% in the conservative group. One patient in the surgical group developed superficial pin-site infection, while two patients in the conservative group developed pressure sores beneath the cast; all recovered fully following dressing changes. Preoperatively, the BA showed no significant difference between the surgical (79.35° ± 2.38°) and conservative groups (78.59° ± 1.96°, P > 0.05). However, immediately after treatment, the BA in the surgical group (71.56° ± 2.56°) was significantly smaller than in the conservative group (73.44° ± 1.76°, P < 0.05). Furthermore, at the 3-month follow-up, the surgical group maintained significantly better BA correction (72.80° ± 2.08°) compared to the conservative group (78.07° ± 2.58°, P < 0.05). At 3 months postoperatively, the CA was significantly better in the surgical group (11.88° ± 1.58°) compared to the conservative group (3.26° ± 4.21°, P < 0.05). At the final follow-up, elbow range of motion was similar between groups, with 157.19° ± 4.27° in the surgical group and 159.50° ± 5.88° in the conservative group (P > 0.05). However, MEPS at the final follow-up differed significantly between the groups, with all 20 cases graded as excellent in the surgical group, whereas in the conservative group, 21 cases were excellent and 5 cases good (P < 0.05).(Table 1).

Table 1.

Comparison of patients’ general information and outcome measures between two groups of pediatric Supracondylar humeral fractures with medial column impaction

Groups	n	Gender(female/male)	Age(years, x ± s)	Preoperative BA	Postoperative BA	BA at 3 months postoperatively	CA at 3 months postoperatively	Fracture healing time(d)	Postoperative elbow joint range of motion	MEPS at the last follow up (excellent/good)	Complication (without/with)
surgical group	20	12/8	8.35 ± 2.18	79.35 ± 2.38°	71.56°±2.56°	72.800°±2.08°	11.88°±1.58°	27.60 ± 1.85	158.87 ± 2.35°	20/0	19/1
conservative group	26	17/9	8.23 ± 1.80	78.59 ± 1.96	73.44°±1.76°	78.07°±2.58°	3.26°±4.21°	27.85 ± 2.33	157.92 ± 1.82°	21/5	24/2
c²/t		0.141	0.23	1.185	-3.269	-7.464	8.683	-0.388	1.547	0.609	0.134
P		0.708	0.840	0.242	0.002	0.000	0.000	0.700	0.129	0.435	0.714

Discussion

The subtype supracondylar humeral fracture is characterized by impaction and collapse of the medial column while maintaining the relative integrity of the lateral cortical periosteum. This fracture subtype resembles the pediatric “greenstick” fractures commonly seen in long bones [3]. During closed reduction, disruption of the lateral periosteum and cortex is often necessary. However, due to medial column impaction and the intrinsic “greenstick elasticity” of the lateral periosteum in pediatric patients, conservative treatment with plaster immobilization frequently leads to progressive medial column collapse, loss of the corrected BA, and eventual development of cubitus varus deformity [12]. Timothy B. modified the Gartland classification of pediatric supracondylar humeral fractures by specifically introducing a subtype involving medial column compression and impaction, characterized by loss of BA, and recommended active intervention with percutaneous Kirschner wire fixation to correct and stabilize these fractures [5]. Similarly, Mudit Shah further subdivided Gartland type I fractures into types IA and IB, defining type IA fractures as true nondisplaced supracondylar humeral fractures and type IB fractures as minimally displaced injuries involving medial column comminution or varus impaction. Shah emphasized that type IB fractures should undergo closed reduction and percutaneous pin fixation to prevent cubitus varus deformity [6].

In the present study, we modified the traditional percutaneous K-wire fixation technique by initially inserting a medial K-wire through precise localization of the medial epicondyle. By using this medial K-wire as a lever, we applied lateral pressure to reduce medial impaction fully, followed by securely anchoring the wire into the opposite cortex. This approach effectively prevented recurrent medial column collapse, maintained stable fracture reduction, promoted fracture healing, and facilitated the restoration of elbow function.

Advantages of percutaneous Kirschner wire fixation for pediatric Supracondylar humeral fractures with medial column impaction

Superior restoration of BA and CA with anatomically satisfactory alignment postoperatively

The BA is widely used to evaluate fracture reduction quality in the coronal plane for pediatric supracondylar humeral fractures, with the normal range reported between 64° and 81° [13]. Maintaining an appropriate BA is considered critical, as it significantly influences CA during subsequent childhood growth and serves as a primary factor in preventing cubitus varus deformity [14, 15]. Some studies suggest that medial displacement of the distal fragment constitutes an independent risk factor for the development of cubitus varus deformity after supracondylar fractures [7]. Moreover, Miura et al. reported that loss of BA following supracondylar fractures might increase the risk of subsequent lateral humeral condyle fractures [16]. Given that medial column compression or impaction inherently results in loss of the BA, most authors emphasize the importance of adequately restoring this angle during fracture reduction [17].

In this study, we applied a novel surgical approach wherein the medial epicondyle was manually displaced laterally using the surgeon’s thumb, while simultaneously leveraging the partially inserted K-wire until maximum correction of medial impaction was achieved. The K-wire was then securely anchored through the opposite cortex to maintain medial column stability and prevent recurrent impaction. Immediate postoperative and three-month follow-up evaluations revealed significant improvements in both BA and CA, demonstrating statistically significant differences compared with the conservative treatment group.

A simple, safe procedure with a low rate of complications

Closed reduction with percutaneous K-wire fixation has become widely accepted as the standard treatment for significantly displaced pediatric supracondylar humeral fractures. Regarding pin placement, crossed medial and lateral K-wires are advocated by most researchers to enhance fixation stability [18]. In our study, we similarly utilized one medial and two lateral K-wires placed in a crossed-pin configuration, effectively preventing postoperative fracture displacement. Previous biomechanical studies specifically highlighted the necessity of medial pin fixation in fractures involving medial column compression [17, 18]. Although medial pin placement carries a potential risk of ulnar nerve injury, several strategies have been proposed to mitigate this risk, including the use of small incisions and retractors for nerve protection [19, 20]. In our study, ulnar nerve protection was achieved by initially localizing the medial epicondyle and continuously placing the surgeon’s thumb directly over the ulnar nerve and groove during pin insertion. Continuous monitoring for involuntary movements of the patient’s ring and little fingers was also performed to prevent nerve injury. Consequently, the complication rate in our surgical group was low, with only one case of superficial pin-site infection and no cases of ulnar nerve injury, showing no statistically significant difference compared with the conservative treatment group.

At the final follow-up, elbow joint range of motion was similar between groups (surgical group: 157.19 ± 4.27° vs. conservative group:159.50 ± 5.88°, P > 0.01). However, the MEPS demonstrated significantly better functional outcomes in the surgical group (20 excellent) compared to the conservative group (21 excellent, 5 good; P < 0.05). The observed cubitus varus deformity and elbow instability in the conservative treatment group likely contributed to their lower MEPS.

Technical considerations and key points of percutaneous Kirschner wire fixation

1. Precise localization of the medial epicondyle is critical. It can be palpated using the surgeon’s thumb. In cases with significant medial swelling, the soft tissue can be displaced posteriorly by firm thumb pressure to expose the bony prominence. If necessary, fluoroscopic guidance with a C-arm can assist in accurate localization.

2. During insertion of the medial K-wire, the surgeon’s thumb should remain constantly positioned over the ulnar nerve and the ulnar groove for protection. Proper insertion angle is essential; ideally, the wire should be parallel to the sagittal plane of the humeral shaft and inclined at approximately 45° in the coronal plane.

3. Leveraging the medial epicondyle as a fulcrum, the medial epicondyle should be pushed laterally using the surgeon’s thumb together with the partially inserted K-wire held in the drill chuck. When maximal lateral displacement is achieved, the K-wire should be advanced further to engage and penetrate the opposite cortex, maintaining stable fixation.

4. All manipulations should be performed with the affected limb positioned directly over the C-arm receiver. If initial correction of medial impaction is incomplete, the K-wire can be slightly withdrawn from the opposite cortex, and greater lateral pressure applied again to achieve satisfactory alignment.

5. Close monitoring of involuntary movement of the patient’s ring and little fingers is essential during K-wire insertion to prevent ulnar nerve injury.

However, several limitations should be acknowledged in this study. These include a relatively small sample size, the non-randomized allocation based on parental choice, absence of long-term follow-up data, and lack of biomechanical testing. Future studies should incorporate larger sample sizes, randomized controlled trials, extended follow-up periods, and relevant biomechanical assessments to further confirm the clinical efficacy and safety of percutaneous K-wire fixation for pediatric supracondylar humeral fractures with medial column impaction.

Conclusion

Percutaneous K-wire fixation demonstrates good clinical efficacy and reliability in the treatment of pediatric supracondylar humeral fractures with medial column impaction. This surgical method effectively restores both the CA and BA of the affected elbow joint, yielding superior outcomes compared to conservative treatment by closed reduction and casting alone.

Abbreviations

CA

Carrying angle

BA

Baumann angle

MEPS

Mayo Elbow Performance Score

K-wire

Kirschner wire

Author contributions

The study was conceived and designed by LY and YL; Data acquisition was done by ZZ and SC; Statistical analysis was performed by ZZ and SC; The drafting of the manuscript and critical revision was written by LY，RG and YL, and the final version of manuscript was approved by RG and YL. All authors contributed to the article and approved the submitted version.

Funding

This research was supported by Anhui Medical University Scientifc Research Foundation Project (No. 2023xkj103).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

This study was approved by the Medical Ethics Committee of Anhui Province Children’s Hospital (EYLL-2023-024). This study was conducted in accordance with the declaration of Helsinki. Written informed consent was obtained from the legal guardians of all participants.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.