Introduction
Humeral lateral condylar fractures (HLCF) are children's second most prevalent kind of elbow fracture, accounting for 17%–20% of all fractures (1–5). Since the fracture is intra-articular, anatomical repositioning must be performed afterward. However, anatomical repositioning is performed mainly by surgical intervention (with pin fixation or cannulated screw fixation) for significantly displaced or rotated HLCF. Open reduction with pin fixation (ORPF), a conventional surgical technique, is highly effective (6–8). Pediatric HLCF has recently been treated using closed reduction percutaneous pinning (CRPP). CRPP has particular advantages regarding functional outcomes, complications, and unaesthetic scars (9, 10).
Nevertheless, some researchers maintain that ORPF offers more substantial advantages, including better repositioning and fewer complications (11). As a result, perspectives on the surgical technique for pediatric HLCF are mixed. To provide clinical decision-making guidance, this systematic review and meta-analysis compared the functional outcomes, complications (superficial infection, deep infection, avascular necrosis of the humeral capitulum (ANHC), poor fracture union, and unaesthetic scars), and lateral spur formation (LSF) between the two surgical approaches.
Methods
Search strategy
(“humeral fracture, distal” [MeSH term] OR “humeral lateral condylar fracture” OR “humerus lateral condylar fracture” OR “lateral condylar fracture of the elbow”) AND (child[MeSH term] OR children OR pediatric) were searched for in the electronic databases Pubmed, Embase, Cochrane Library, and Web of Science without regard to ethnicity or language from inception to February 10, 2023. Moreover, references to all contained literature were evaluated.
Selection criteria
Inclusion criteria: (1) All controlled studies of ORPF and CRPP for treating HLCF in children, including randomized controlled, nonrandomized case-control, retrospective case-control, and prospective cohort studies. (2) All patients with clinical manifestations and imaging diagnoses of HLCF were under 16 years old and had obvious surgical indications, regardless of race, country, or gender. (3) Outcomes included one or more of the following: functional outcomes, complications (superficial infection, deep infection, ANHC, poor fracture union, unaesthetic scar), and LSF.
Exclusion Criteria: (1) Case reports, case series, reviews, and correspondence. (2) The presence of other morbidities can have a significant effect on therapy and prognosis, multiple or open fractures. (3) HLCF is treated non-operatively or surgically without using a Kirschner wire. (4) The clinical outcomes were not reported in the studies.
Study selection
A single reviewer applied the selection criteria to all publications obtained by the search strategy. Two reviewers evaluated the inclusion of identified studies. A third researcher could be consulted if disagreements concerning the literature's suitability arise. The titles of publications and authors' identities were not hidden throughout the selection procedure.
Quality assessment
Using the Methodological Index for Trials (MINORS) with a total score of 12 as inclusion criteria, the methodology quality and bias risk of nonrandomized controlled studies were assessed by two researchers. The same two researchers utilized the Newcastle-Ottawa Scale (NOS) to assess prospective cohort and retrospective case-control studies, with a maximum score of 8, focusing on population selection, comparability, and outcome/exposure, and only studies with a score of 5 were included.
Data extraction
Two researchers independently extracted the obtained data, and in the case of a dispute, the data were resolved by consultation, if required, with the participation of third researchers. Extracts included background information such as the first author's name, publication year, nation, sample size, type of research, and follow-up.
The significant outcome of interest was the functional outcome, graded with a rating of excellent, good, moderate, or poor. We primarily assessed the excellent and good rates of joint function following two surgical procedures. Secondary outcomes included superficial infection, deep infection, ANHC, poor fracture union, unaesthetic scar, and LSF. The number of individuals who dropped to follow-up was also a study characteristic. A solitary reviewer collected data on data abstraction forms from the selected studies.
Statistical analysis
A meta-analysis was proposed if populations, interventions, and outcome assessments in trials were clinically homogenous. For statistical analysis, Review Manager 5.4 was employed. The odds ratio (OR) and 95% confidence interval (CI) were computed for a binary variable. Using the chi-square and I2 tests, heterogeneity between selected literature was assessed. The pooled ORs were calculated using the fixed effects model if the associated P value was more than 0.05 or the I2 was less than 50%, indicating decreased heterogeneity across studies; otherwise, the random-effects model was utilized. In cases of significant heterogeneity, sources of heterogeneity were investigated by either modifying the effect model used for the meta-analysis or removing each search individually.
Discussion
HLCF is an intra-articular fracture caused by indirect violence (20), and improper treatment can result in complications such as poor fracture union, cubitus varus or valgus deformity, ANHC, and elbow joint dysfunction due to fracture involvement of the epiphysis (21, 22). CRPP and ORPF are routinely used in patients with severe displacement requiring surgical therapy. However, there is no clinical conclusion as to which of these two treatments is more beneficial, and most research compares them in terms of functional outcomes and complications. Some clinicians argue for using CRPP, claiming that the major drawback of ORPF is the interruption of blood supply following trans-lateral elbow incision, which is deleterious to fracture union and even raises the risk of ANHC (23). However, it has also been suggested that an overemphasis on CRPP and neglect of ORPF might increase soft tissue damage, with higher rates of nerve and vascular injury in some situations of repeated closed repositioning, therefore compromising the postoperative outcome. Consequently, more investigation into the effectiveness and safety of these therapy approaches is required.
There are several fracture classification criteria for pediatric HLCF. Three of the seven included studies used the Song Criteria (12, 14, 18), with all patients having type III-V; three studies used the Jakob Criteria (13, 17, 19), with all patients having type II or higher; and three studies used the Milch Criteria (15, 16, 19), with all fractures having Milch type II. Four of the seven included publications assessed functional outcomes, with two studies employing Hardacre criteria (17, 18), one using Llynn criteria (12), and one without defining evaluation criteria (15). All functional outcomes were rated excellent, good, moderate, or poor. It has been shown that functional recovery of the elbow joint is faster following CRPP, particularly for fractures with displacement less than 4 mm (9, 10, 24), and an excellent and good rate of 98.8% of functional outcomes after CRPP has been reported (25). However, other studies argue that CRPP may impede the functional outcomes for rotated fractures; hence, ORPF is more usually recommended (26), and postoperative joint stiffness and loss of joint mobility may impede the functional outcomes. Nevertheless, functional outcomes and fracture severity were found to be correlated by Changzong Deng et al. (27).
The frequency of excellent and good functional outcomes in the CRPP group was 95.08% for all HLCF children included in this study, which was lower than the literature reported. This study discovered no substantial difference between CRPP and ORPF in functional outcomes, demonstrating that while ORPF may cause more significant soft tissue injury, it does not affect functional outcomes. Both surgical procedures can restore elbow function to an acceptable degree through functional exercise with a sufficiently long follow-up. Functional exercise is believed to improve blood flow in the affected limb, making it more susceptible to trauma repair and fracture union. Stretching and contraction of muscles can activate blood flow in the joint and surrounding tissues, promoting synovial fluid secretion and flow and maintaining normal nutrition of articular cartilage.
Most of the supply of blood for the epiphyseal plate comes from its lateral muscles and soft tissue attachment points such as ligaments, and ORPF will undoubtedly further disrupt fracture blood flow; consequently, it has been learned that ORPF increases the incidence of complications and Iames et al. reported that ORPF could lead to medically induced complications such as poor fracture union, ANHC, and ossifying myositis (28). Kini et al. discovered that the destruction of soft tissues at the fracture site caused complications such as malunion and elbow stiffness, which hindered the functional rehabilitation of the elbow joint during follow-up (29). However, this meta-analysis found no statistical difference between both groups in complications.
There was no statistical difference between the two surgical procedures in the superficial and deep infection prevalence. Despite requiring additional soft tissue damage and incision exposure, ORPF did not enhance the incidence of postoperative infection. Superficial infections, such as pin site and incisional infection, are usually fully recovered with oral antibiotics or Kirschner wire removal. In contrast, managing deep infections, such as septic arthritis and osteomyelitis, is more complicated and can leave a degree of sequelae if not appropriately handled.
Delayed union, nonunion, and malunion may occur following pediatric HLCF, and we refer to these complications as poor fracture union. Poor fracture union can occur for various reasons, including soft tissue damage caused by the fracture or surgery, where blood flow to the fracture block is compromised, and premature postoperative activity leading to fracture instability. Some researchers believe ORPF induces blood supply disruption and raises the risk of poor fracture union (23), hence proposing CRPP. In contrast, several studies suggest that CRPP is more prone to fracture union failure (10). Our study found no statistical difference in the occurrence of poor fracture union between the two interventions. The periosteum and distal fracture block should not be stripped excessively during ORPF. Muscle pulling off the fracture block should be avoided as much as possible (30), as well as the need for a solid external postoperative fixation.
ANHC is a more severe complication of HLCF that can seriously affect functional outcomes. However, its origins are unknown for the time being. ShabtaiLiorl et al. observed an incidence of around 1.4% (31). They identified its key risk factors as high-energy injury and empty repositioning, as well as its morphological and physiological causes as soft tissue stripping and blood supply loss. Skak SV et al. also reported a 0%–7% incidence of ANHC, which can induce consequences such as elbow valgus, which is more challenging to manage (32). Thus, avoidance of ANHC is emphasized. Although CRPP has been shown to decrease the incidence of ANHC (33, 34), In this investigation, we found no statistical difference in the occurrence of ANHC between the two surgical procedures. However, reducing soft tissue injury during surgery may decrease the risk of ANHC.
Due to the requirement of a surgical incision, the ORPF group produced significantly more unaesthetic scars than the CRPP group, which is a benefit of CRPP.
For HLCF, LSF occurs more commonly after surgery. Its incidence has been estimated in the literature to range from 45% to 77%, yet it has little to no effect on functional outcomes. Most of it will be patterned and resorbed later on, and the displacement of the fracture's distal periosteum and the development of new bone may have contributed to its occurrence (35). We do not categorize LSF as a complication since it is virtually universally asymptomatic. In this meta- analysis, we could not identify a substantial difference in LSF incidence rates between the two arms in the current study; thus, we do not believe that the surgical approach influences the development of LSF.
The research does have some flaws, however. (1) The available literature lacks high-quality randomized controlled trials, and the samples of certain studies are small; hence, more randomized controlled studies with larger samples are necessary to provide more credible conclusions. (2) Complications in this Meta-analysis only included infection, poor fracture union, ANHC, and unaesthetic scar. This meta-analysis did not cover more complications, so it was impossible to fully illustrate the benefits and drawbacks of CRPP vs. ORPF in avoiding complications. As a result, the conclusions could have been more reliable. (3) Because CRPP is a novel surgical technique, the varied technical competency of the surgeons may also impact the outcomes and, consequently, compromise the validity of the conclusions of the Meta-analysis.