1 Introduction

Olecranon fractures are a common injury in adults, accounting for approximately 10% of upper extremity fractures.¹ This injury is typically treated operatively with plate fixation or tension band wiring.^2,3 Plate fixation provides stable fixation, is associated with high union rates, and is associated with a low rate of elbow stiffness or weakness that affects quality of life.^4–6

Despite the excellent prognosis and functional outcomes associated with operative fixation of this injury, implant irritation and/or discomfort remain a common postoperative complication that often lead to elective implant removal.^7,8 Otherwise, patients typically have good functional outcome following operative treatment of olecranon fracture, with 96% of patients reporting good or excellent functional outcomes at 15–25 years of follow-up.⁹ Mini-fragment plate fixation of olecranon fractures, using 2.7 mm implants or smaller, offers the potential of less prominent implants in this location. Clinical studies have demonstrated that mini-fragment fixation of olecranon fractures is safe and efficacious.¹⁰ In biomechanical testing, mini-fragment plate fixation had similar construct stability to precontoured plates.¹¹

However, there remains no comparative studies to date on symptomatic implant rates after mini-fragment plate fixation of olecranon fractures. Thus, we compared rates of symptomatic implants and subsequent implant removal of surgeon contoured mini-fragment plates and precontoured olecranon specific plates. We hypothesized that mini-fragment plates would decrease implant removal compared to precontoured plates.

2 Methods

Institutional Review Board approval was obtained (approval # 54758). We conducted a retrospective review of patients undergoing plate fixation of isolated olecranon fractures (AO/OTA 2U1 B1) between 2004 and 2020.¹² AO/OTA fracture classification was determined via retrospective review of injury radiographs by two orthopaedic surgeons (L.H.G., M.R.D.). Exclusion criteria were pathological fracture, tension band wiring, olecranon osteotomy, follow-up of less than three months and complex olecranon injury patterns such as concomitant radial head or distal humerus fracture or fracture-dislocations. All cases were performed by orthopaedic surgeons at a single institution at a level-1 trauma center in the United States. 530 records were reviewed, of which 269 met inclusion criteria. 139 were lost to follow-up.

Patients were stratified into two cohorts based on fixation construct: (1) treatment with mini-fragment fixation (2.7 mm implants or less and manually contoured) (DePuy Synthes, West Chester, PA; Zimmer Biomet, Jacksonville, FL; Smith and Nephew, Memphis, TN) and (2) treatment with a precontoured olecranon-specific plate (DePuy Synthes, West Chester, PA; Zimmer Biomet, Jacksonville, FL; Acumed, Hillsboro, OR) (Figs. 1 and 2). Otherwise, surgical treatment proceeded according to attending surgeon preference. In the majority of cases, patient was positioned lateral decubitus, with posterior utility approach to the olecranon via the extensor carpi ulnaris/flexor carpi ulnaris deep interval. Proximally, the triceps is elevated via a longitudinal incision in its fibers to allow the plate to lay directly on the osseous surface, and at the end of the procedure is repaired over the plate. There were no differences in the postoperative rehabilitation protocol between the two groups. Postoperative rehabilitation involved non-weightbearing and unrestricted range of motion exercises 2–3 times per week for 6–8 weeks, followed by progressive strengthening exercises 2–3 times per week for 8 weeks.

Close

Fig. 1 Lateral elbow radiographs at the preoperative (A,D), intraoperative (B,E), and three month postoperative timepoints (C,F) of olecranon fracture stabilized with precontoured olecranon-specific plate (top) or mini-fragment plate (bottom).

Export to PPT

Close

Fig. 2 Long-term radiographic follow-up. AP and lateral elbow radiographs at the six month (A,B,E,F) and twelve month (C,D,G,H) postoperative timepoints of olecranon fractures stabilized with precontoured olecranon-specific plate (top) or mini-fragment plate (bottom).

Export to PPT

Recorded variables included patient demographics, body mass index, American Society of Anesthesiologists score, tobacco use, diabetes, fracture characteristics, type of fixation, and any postoperative complications or reoperations. The primary outcome of the study was symptomatic implant after surgery, defined as any subjective or objective irritation, pain, or soft tissue discomfort corroborated with direct palpation on physical exam after uncomplicated complete healing was confirmed on postoperative radiographs at final in-person or telemedicine follow-up. All patients had a minimum of three months of in-person follow-up. Thirty-one patients had telemedicine follow-up after the 3 month timepoint. Secondary outcomes were operative time, implant removal, postoperative complication, and reoperation. Patients who underwent elective implant removal for symptomatic implant were included under reoperation but not postoperative complication, as this was not a complication of olecranon fixation.

Student's t-test and Fisher's exact test were performed for comparison of continuous and categorical variables, respectively. Significance was defined as p < 0.05. Univariate logistic regression analysis was performed to identify factors (i.e., age, sex, BMI, tobacco use, diabetes, and plate type) associated with implant removal. All statistical analyses were performed using SAS Enterprise Guide (Cary, NC).

3 Results

In total, 130 patients met inclusion criteria, of which 98 were treated with precontoured plates and 32 with mini-fragment plates. Mean follow-up was 20.6 months (range, 3–170 months). The cohort was 55.4% (72/130) female, and the mean age at surgery was 54.4 ± 1.8 years. In our series, 13.8% (18/130) (BMI >30) were obese, 6.2% (8/130) were diabetic, and 21.5% (28/130) used tobacco. In this cohort, 8.5% (11/130) of fractures were open. Baseline demographics and comorbidities were comparable between the precontoured and mini-fragment cohorts (Table 1).

Operative time was significantly longer in the precontoured plating group compared to the mini-fragment plating group (124.5 ± 58.5 min vs. 92.8 ± 35.3 min; p < 0.01). Fractures stabilized with precontoured plates did not have significantly different rates of postoperative complication (22/98, 22.4% vs. 5/32, 15.6%; p = 0.41) or reoperation (37/98, 37.8% vs. 8/32, 25%; p = 0.22) compared to fractures stabilized with mini-fragment plates.

In the mini-fragment cohort, there were two cases of peri-implant fracture, one case of fixation failure and deep infection, one case of elbow contracture, and one case of post-traumatic arthritis.

In the precontoured cohort, there was one case of ulnar neuritis that did not undergo decompression, one case of urinary retention, one case of suture abscess, and one case of heterotopic ossification that did not undergo reoperation. Reoperations were as follows: one case of ulnar nerve entrapment that underwent decompression, one nonunion revision, one revision for peri-implant fracture and subsequent infection, one revision for hypertrophic scar, and one reoperation for post-traumatic contracture. Additionally, there were three cases of deep infection, one of which resulted in fixation failure. There were two additional cases of fixation failure. Four additional patients experienced heterotopic ossification that underwent revision, one of which had concomitant post-traumatic contracture. There were four cases of wound dehiscence. One wound dehiscence was associated with a seroma formation and arthrofibrosis, another with skin necrosis, and another with osteomyelitis, infected implants, septic arthritis, and elbow contracture with heterotopic ossification. All cases went on to eventual union.

The rate of symptomatic implants was significantly higher in the precontoured cohort (44/98, 44.9% vs. 7/32, 21.9%; p < 0.05). The rate of implant removal was 36.7% (36/98) in the precontoured group compared to 18.8% (6/32) in the mini-fragment group (p = 0.06) (Table 2).

In a simple logistic regression model, none of the variables assessed were associated with implant removal. In a multi-level logistic regression model, primary treating surgeon was not associated with implant removal. (p = 0.8668) In a multivariable logistic regression model, age and mini-fragment plating were not independently associated with implant removal (Table 3).

4 Discussion

In this retrospective study, we found that olecranon fracture patients treated with mini-fragment plates were less likely to report symptomatic implants compared to patients treated with patients treated with precontoured olecranon specific implants. We also found a trend towards less implant removal in the patients treated with mini-fragment implants. Complication rates were similar between groups, leading us to conclude that manually contoured mini-fragment plate fixation of olecranon fractures appears to be a safe alternative to precontoured olecranon plating.

Postoperative complication rates of plate fixation range from 0 to 38% in the literature.^7,13–17 A recent meta-analysis reported that plate fixation carried an overall complication rate of 22%.¹⁸ Consistent with these findings, the complication rates in our cohort were 22.4% (22/98) and 15.6% (5/32) for precontoured and mini-fragment plates, respectively. Implant removal rates after plate fixation vary between 9 and 56% in the literature.^6,7,18–22 In our study, we identified implant removal rates of 36.7% and 18.8% for precontoured and mini-fragment plates, respectively. Additionally, we found that age, sex, BMI, tobacco use, and diabetes were not predictors of implant removal in our cohort. In another recent retrospective review, however, both decreasing age and lower BMI were associated with symptomatic implants and implant removal.²³

Mini-fragment plate fixation is designed to minimize subcutaneous plate prominence without sacrificing stability, and thus decreasing the rate of symptomatic implants and potentially the need for implant removal. Mini-fragment fixation has also been found to be a viable alternative in clavicle, talar neck, and tibial plafond fractures.^24–27 In olecranon fractures, mini-fragment plate fixation is both safe and effective.^10,28 A recent biomechanical study revealed that 2.7 mm plating of olecranon fracture reduced implant prominence without compromising construct stability.¹¹ The current study builds upon this research by demonstrating that mini-fragment plates are less symptomatic and may decrease the rate of implant removal. Interestingly, a recent study of a novel low-profile double plate fixation technique for olecranon fractures demonstrated a good clinical outcome but did not reduce implant removal.²² This may suggest that low-profile constructs are not sufficient to reduce the risk of implant removal, which is consistent with the findings of a previous retrospective study that reported that implant prominence is not associated with symptomatic implants or implant removal.²³ Additionally, number and placement of screws impact symptoms of implant irritation,²⁹ a phenomenon which may also extend to mini-fragment plates. In our study, we saw a trend towards decreased implant removal rates in patients treated with mini-fragment plating (p = 0.06). We believe that implant removal rates may be lower with mini-fragment plating, but that this study was underpowered to detect a statistically significant difference.

This study is inherently limited by its retrospective nature. Plate selection was performed per attending surgeon preference. Furthermore, there was a limited follow-up period, though we felt it sufficient to assess for implant-related discomfort. It is important to note that symptomatic implants may present later as swelling diminishes. However, patients presented as needed after uncomplicated healing. Furthermore, we performed a phone call follow-up to assess implant-related discomfort at a standardized timepoint and minimize the impact of the follow-up period. We did not assess the effect of mini-fragment plating on functional outcomes or patient-reported outcome measures, and this information should be the focus of future research. Finally, the decision to retain or remove an implant is subject to many biases and our implant removal rates may not be generalizable. Nonetheless, this is the first study to rigorously compare the rates of symptomatic implants and implant removal after olecranon fracture stabilization with mini-fragment and precontoured olecranon plates, and we feel it contributes meaningfully to the available literature on this topic. Further prospective randomized trials on this topic will be needed to confirm the findings of this study.

5 Conclusion

Olecranon fracture stabilization with mini-fragment implants is safe and results in less symptomatic implants, without resulting in increased postoperative complications or unplanned reoperations compared to precontoured olecranon plates.

Funding

The authors did not receive support from any organization for the submitted work.

Ethical approval

This study was approved by our institution's IRB.

Informed consent

Requirement for informed consent was waived by our institution's IRB.

CRediT authorship contribution statement

Harsh Wadhwa: Conceptualization, Methodology, Formal analysis, Investigation, Writing – original draft, Writing – review & editing. Yousi A. Oquendo: Methodology, Formal analysis, Investigation, Writing – original draft, Writing – review & editing. L. Henry Goodnough: Conceptualization, Writing – review & editing. Malcolm R. DeBaun: Conceptualization, Writing – review & editing. Julius A. Bishop: Writing – review & editing. Michael J. Gardner: Writing – review & editing, Supervision.