Clinical Outcomes and Management Strategies for Capitellum and Trochlea Fractures: A Systematic Review

Introduction

Isolated capitellum and trochlear fractures, also referred to as coronal shear fractures of the distal humerus, although infrequent, carry substantial clinical importance. The critical role within the elbow joint was initially underscored by Morrey et al in 1985, who highlighted the intricate nature of these fractures and their potential for significant functional impairment.¹ In the ensuing years, several classifications have been proposed to help guide management. Two are frequently utilized in clinical practice and were established by Dubberley et al and Bryan and Morrey et al, with the latter being further modified by McKee et al to account for the presence of a trochlear fragment.^2,3 These classification systems have been instrumental in guiding treatment choices and prognostic considerations.

Recognizing the crucial role of articular congruence and early rehabilitation to improve outcomes, open reduction and internal fixation (ORIF) is widely considered the standard treatment modality.⁴ However, the literature is abundant with studies advocating for different techniques, implants, and approaches, creating a somewhat scattered landscape of data. Given the array of available techniques, the selection of the optimal approach remains controversial. Whether to opt for screw fixation, tension band wiring, or more contemporary methods involving plate fixation often depends on the surgeon’s preference, influenced by their training and the available literature.

Despite advancements in surgical techniques and the variety of approaches and fixation methods available, the outcomes following these fractures remain variable. This inconsistency in outcomes is likely attributable to the inherent complexity of the elbow joint, the frequent postoperative stiffness, and the challenges associated with restoring articular congruence. In this systematic review, we aim to report on the overall operative interventions, their associated outcomes and complications linked with isolated capitellum and trochlea fractures.

Methods

The search and selection process followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was prospectively registered with PROSPERO (International Prospective Register of Systematic Reviews) (ID: CRD42022327859).

Search Strategy

A systematic search of Medline, Embase, Web of Science and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases was performed using the following keywords: (Fractures) AND ((Capitellum) OR (capitellar) OR (Distal humerus) OR (Coronal Shear)). This strategy was undertaken to maximize the inclusion of all the potentially relevant articles with variation in terminology. Finally, reference lists of relevant articles were reviewed to identify additional articles that were potentially missed during the initial search.

Eligibility Criteria

Studies that met the following criteria were included: 1) reporting outcomes of operatively treated capitellum or capitellar-trochlear fractures; 2) reporting outcomes of at least 5 patients and 3) patient age >18 years.

Studies were excluded if they met any of the following criteria: 1) review articles; 2) full text not available; 3) cadaveric or biomechanical studies; 4) studies that do not report the outcomes of patients with capitellum and/or trochlea fractures separately, if they included concomitant elbow injuries such as dislocations, extra-articular distal radius fractures, radial head fractures, coronoid fractures and olecranon fractures; 5) concomitant ipsilateral upper limb fractures.

Study Screening

Titles and abstracts were independently screened for relevance by three authors using Covidence (Covidence systematic review software, Veritas Health Innovation, Melbourne, Australia. www.covidence.org). Potentially relevant articles underwent full-text screening, with any conflicts between the authors being resolved by discussion and consensus with the senior authors.

Quality Assessment

Study quality assessment was conducted using the methodological index for non-randomized studies (MINORS) tool.⁵ A score of 0, 1 or 2 is given for each of the 12 items on the MINORS checklist with a score of up to 16 for non-comparative studies and 24 for comparative studies. Methodological quality was categorized prior as follows: a score of 0–8 or 0–12 was considered poor quality, 9–12 or 13–18 was considered fair quality, and 13–16 or 19–24 was considered excellent quality, for non-comparative and comparative studies, respectively. For randomized controlled trials, the Cochrane risk of bias 2 (RoB-2) was used. Quality assessment was performed by two independent reviewers, with any conflicts between the authors being resolved by consensus with the senior authors.

Data Extraction

Three authors independently extracted relevant data from the included studies to a previously piloted Microsoft Excel spreadsheet (Microsoft, Redmond, Washington, USA). These data included general article information (title, author, date of publication, journal, originating country and contact information), sample data and methodological information (study design, sample size, level of evidence, inclusion/exclusion criteria), patient demographic and surgical procedure details (age, gender, surgical approach, method of operative interventions), and relevant outcome measures (follow-up period, patient reported outcome scores, range of motion, complications and revision surgery). Scoring systems utilized included Disabilities of the Arm, Shoulder and Hand (DASH), quick DASH (Q-DASH) and the Mayo Elbow Performance index (MEPI).

Data Analysis

Descriptive statistics including the mean, range and measures of variance (eg, standard deviations, 95% confidence intervals [CI]) were utilized where applicable. Data were synthesized into pooled demographics, treatment, and outcome measures. Due to the high heterogeneity of the interventions and included outcome measures, subgroup analysis was not possible. Measures of spread were calculated from each study if individual data were reported.

Results

After the removal of duplicates from the initial search, a total of 6596 references were retrieved for title and abstract screening (Figure 1). A total of 6357 were excluded after the initial title/abstract screening. Next, 239 studies underwent full-text review. A total of 41 studies were included in the final analysis.

Figure 1 PRISMA flowchart depicting the process of study inclusion.

Sample Data

The study designs and demographics of the pooled patients are detailed in Table 1. Apart from one randomized controlled trial comparing different surgical approaches, all studies were retrospective series and cohorts. A total of 700 patients were included with a female preponderance (57%). The mean age was 43.8 (± 11.4) with a mean follow-up of 31 (±20.2) months. The Dubberley and Bryan and Morrey classifications were the most commonly reported (Figures 2 and 3).

Table 1 Patient Demographics and Characteristics

Figure 2 Illustration of the Bryan and Morrey classification for capitellum fractures with the McKee modification. I: Large osseous capitellum piece, II: Shear fracture of the articular cartilage, III: Comminuted fracture of the capitellum, IV: McKee modification that includes a coronal shear of the capitellum and trochlea.

Figure 3 Illustration of the Dubberley classification for capitellar and trochlear fractures. Type I: fractures of the capitellum with/ without lateral trochlear ridge, type II: Fractures of the capitellum and trochlea as one piece, III: fractures of the capitellum and trochlea as separate fragments. In addition to (A) Without posterior wall comminution, (B) with posterior wall comminution.

Interventions

The surgical approach, types of implants used for fixation and screw configurations are displayed in Table 2. The most utilized approach was the lateral approach (L) (79%), followed by the antero-lateral (AL) (15%) and posterior approaches (5.5%). Variations of the lateral approach existed and were included in the table when they were reported in the studies. In a comparison of the AL and lateral approach, Yu et al reported comparable outcomes and shorter operative times in the AL approach.²⁷

Table 2 Summarizing Approaches, Implant Selection and Screw Trajectory

Headless compression screws were the preferred fixation method (68%). A combination of plates, screws and Kirschner wires (K-wires) was also common (19%). Plates alone were utilized in 7.5% of the patients, particularly when lateral and posterior wall comminution was present.^21,23,27, The most common screw trajectory was anterior to posterior (AP) in 79%, whereas posterior to anterior screws (PA) were used in 21%.

Patient Reported Outcome Measures (PROMS)

The patient reported outcome measures are depicted in Table 3. The mean aggregate Mayo Elbow Performance Index (MEPI) score was 89.9 (± 2.6) reported in 26 studies (n = 512). The mean aggregate DASH score was 16.9 (± 7.3) reported in 5 studies (n = 74). Of note, Ravishankar et al reported worse MEPI outcome scores with Bryan and Morrey (BM) IV (76.3 ± 16.1) compared to BM III (85.3 ± 10.1).²³

Table 3 A Summary of Functional Outcomes, Union Time, and Range of Motion for the Included Studies

Range of Motion (ROM)

The reported data on ROM in 37 studies is depicted in Table 3. The aggregate mean values for ROM in degrees included flexion 126.3° (±19.4°) extension 5.7° (±11.8°) pronation 75.2° (±12.2°) and supination 76.6° (±9.8°). The mean flexion-extension arc was 113.7° (±13.9°), whereas the mean pronation-supination arc was 165.3° (±9.4°).

Postoperative Protocol

The postoperative protocol varied between studies (Table 3). The majority of studies (n = 26) utilized above elbow slabs for immobilization. The immobilization periods ranged from a few days up to 4 weeks. There was a trend towards shorter immobilization periods in more recent studies. Other postoperative protocols included hinged braces, removable static brace and postoperative arm slings. Physiotherapy was often started after splint removal, with some exceptions to immediate range of motion exercises being started postoperatively.

Complications & Re-Interventions

The complications and re-interventions are summarized in Table 4. The total complication rate was 19.8% (n = 139). The total re-intervention rate was 8.3% with the majority of these consisting of symptomatic implants that required removal. Other complications included; non-union (1.5%), infection (1.2%), stiffness (6%) and implant removal (10.4%). Nerve palsies were reported in 2% of the patient population, more commonly reported in the anterolateral approach.^27,29,41 There was poor reporting of osteoarthritis (OA) as a complication and whether or not these were symptomatic. Eighteen studies reported on OA radiographically detected. There were no details on long-term follow-up and symptoms due to OA. There was also poor reporting of re-interventions for release procedures following elbow stiffness.

Table 4 Complications, Problems and Re-Interventions Across the Included Studies

Discussion

Capitellum and trochlear fractures present unique management challenges due to the complexity of the elbow joint and the intricacies involved in restoring articular congruence while avoiding the risk of stiffness due to delayed rehabilitation. The findings from our review indicate that the current management strategies of this fracture yield acceptable, yet variable mid-long-term outcomes and are accompanied by a relatively high complication rate of (19.8%).

The surgical approaches adopted for these fractures encompassed variations of the lateral, anterolateral, and posterior approaches. The lateral approaches were utilized in almost 80% of the cases and are perhaps most useful for Bryan and Morrey types I–III in which visualization of the capitellum is sufficient to achieve reduction and perpendicular screw trajectories. It is important to note, however, that while the lateral approach allows for the potential repair of lateral collateral ligament (LCL) injuries, it also carries a risk of iatrogenic LCL damage. A thorough examination of stability should be performed to avoid neglecting an LCL injury, resulting in postoperative instability. Additionally, the lateral approach can be beneficial for cases with posterolateral wall comminution, providing direct access for visualization, PA screws and dorsolateral plates.^23,28,36,39

Recently, the anterolateral approach has been gaining popularity in managing more medial trochlear fragments, specifically those of Bryan and Morrey type IV. This method offers direct visualization of both the capitellum and trochlea and facilitates a more perpendicular trajectory to the trochlea. It should be noted, though, that temporary nerve injuries were more prevalent in patients who underwent the anterolateral approach, attributable to the close proximity of the radial nerve during the procedure.^20,24,38,45 As such, identification of the radial nerve should be a priority and subsequently avoid rigorous retraction. While the anterolateral approach offers adequate medial and lateral fragment visualization, dual lateral and medial approaches have been utilized to address more medial fragments.^31,35 The use of arthroscopic-assisted fixation has recently been studied on cadavers with patient implementation in several case reports not included in this review. Although results seem promising, the application of the technique is still in its early stages.⁴⁶

Headless compression screws remain the most utilized method of fixation (68%). Their popularity can be attributed to their ability to provide stable fixation while maintaining a low profile that minimally disrupts the articular surface. Further, combinations of plates, Kirschner wires and screws were also commonly utilized, particularly for lateral wall comminution when compression is not feasible or will lead to an improper fracture reduction. Headless screws must be adequately countersunk and not protrude through the articular cartilage. It is possible that with some degree of avascular necrosis or fracture collapse, the screws back out, resulting in impingement requiring implant removal.

The choice of screw direction was predominantly anterior to posterior (AP), employed in 79% of the cases, despite the theoretical risk of violating the articular cartilage. Comparatively, posterior to anterior (PA) screws were less frequently utilized. The inconsistent reporting of postoperative osteoarthritis (OA) makes it challenging to draw definitive conclusions on the comparative implications of AP versus PA screws. Nevertheless, there is currently no evidence to suggest that AP screws may lead to higher rates of OA, provided screws are appropriately countersunk to avoid intra-articular impingement. The advantages of AP screws are related with the ability to enhance the amounts of threads in the fractured-free fragment and better biomechanical stability.⁴² The postoperative protocol often included some period of immobilization. Earlier studies appeared to use above elbow splints for longer periods of time.^3,7,11 More recent studies have displayed a trend towards shorter periods of immobilization with a maximum time frame of 2 weeks.^{28,29,35,40,42} In fractures amenable to rigid fixation, postoperative immobilization was not utilized, and earlier range of motion was allowed.^16,41,44

When analyzing outcome scores, it is crucial to note that they reflect mild-to-moderate functional limitations, with more complex patterns such as in BM IV resulting in even more functional deficits. A discrepancy arises when studies group various fracture types together, possibly skewing results. Such a practice is not uncommon and may lead to a gap between expected recovery and the patient’s actual experience. Many patients anticipate a complete return to their previous state, but instead, they often find themselves limited to just managing the basic activities of daily living. The variability in the range of motion across the studies is noteworthy, with a flexion-extension arc averaging 113 ± 13.9 degrees. This variability suggests that a significant proportion of patients do not achieve a functional arc of motion post-surgery. Elbow stiffness appears to be a common problem based on these values, yet many of the included studies did not classify these cases as complications, and it is hard to determine how many of these patients avoid the surgical management of elbow stiffness and coped with their ROM deficits.

A high complication rate was observed across studies, with a cumulative incidence of 20%. Implant removal emerged as a frequent issue, accounting for 10% of complications, predominantly for symptomatic implants that had either migrated or become prominent. However, rates of non-union, infection, nerve palsies, and complex regional pain syndrome were low. The reporting of osteoarthritis across studies was inconsistent, precluding any sound conclusions about symptomatology, as no comparative analysis was made. Similarly, the clinical impact of avascular necrosis and heterotopic ossification remained unclear due to inconsistent reporting and lack of comparative data.

Limitations

This review is inherently limited by the predominance of retrospective studies, which typically represent a lower level of evidence. Moreover, many of the included studies did not distinguish outcomes and complications based on fracture patterns and classifications. It is reasonable to think that the different patterns and fracture subtypes will be associated with varied outcomes and have distinct challenges. Another potential factor overlooked in most studies is the time from injury to surgery, particularly relevant for fractures initially missed due to the difficulty of detection in plain radiographs. The true rate of complications may also be underestimated. If we redefine stiffness as a complication, specifically as an inability to achieve functional range of motion, the actual complication rate in our review would markedly increase. This issue extends beyond statistical representations, as it bears significant implications for clinical practice, especially when establishing realistic post-surgical expectations.⁴⁷

Conclusion

The treatment of capitellum and trochlea fractures yields acceptable outcomes with a relatively high rate of complications and reoperations primarily for symptomatic implants and elbow contracture release surgery. There is noteworthy variability in the achieved range of motion, suggesting unpredictable outcomes. Deficits in functionality and range of motion are common after surgery, especially with more complex injury patterns.