Radiographic Humerus Union Measurement (RHUM) Demonstrates High Inter- and Intraobserver Reliability in Assessing Humeral Shaft Fracture Healing

Principles and Evaluation of Bony Unions

Nonunion is a common and costly problem. Unfortunately, there is no widely agreed upon and standardized definition for nonunion. The evaluation of bony union should start with a thorough history and physical examination. The clinician should consider patient-dependent as well as patient-independent characteristics that may influence the rate of healing and evaluate the patient for physical examination findings suggestive of bony union and infection. Radiographs and clinical examination can help confirm a diagnosis of union. When the diagnosis is in doubt, however, advanced imaging modalities as well as laboratory studies can help a surgeon determine when further intervention is necessary.

Intra-Observational and Inter-Observer Agreement of The Radiographic Humerus Union Measurement (RHUM) in Patients Treated with Dynamic Compression Plate for Humeral Shaft Nonunion

BACKGROUND

It is important for orthopedic surgeons to follow the union of the fracture after surgery. This becomes even more important after nonunion surgery. The radiological union scale is popular in the follow-up of unions. However, the intraobserver and interobserver agreement of this scale in humeral nonunion surgery is still not found in the literature.

OBJECTIVE

This study aimed to reveal the intra/interobserver agreement of the Radiographic Union scale (RHUM) for the humerus as well as the relationship between this agreement, plate placement characteristics, and the number of plates in cases where plates were used for surgical treatment of humeral diaphysis nonunion.

MATERIALS AND METHODS

Twenty patients who received surgical treatment for aseptic humeral nonunion at our hospital between 2010-2019 were studied retrospectively. According to RHUM, two observers scored the patients' anteroposterior and lateral radiographs in the postoperative 12th week. The data obtained were statistically analyzed.

RESULTS

The mean age was 52.05±15.88 years. While a single plate was used in 14 cases, a double plate was used in 6 cases. Interobserver agreement was fair-moderate. The interobserver agreement values of the single plate group were significantly higher than those of the double plate group (p<0.05). Interobserver agreement in cases with a lateral plate was significantly higher than in the group where the lateral + posterior plate was applied (p:0.01).

CONCLUSION

In humeral diaphyseal fracture nonunion cases, the number and location of the plate following surgery negatively impact the evaluation of RHUM scores. Given the importance of the union's follow-up and the decision to proceed with additional treatment in these cases, it may be necessary to develop a new method for determining and monitoring the union if a plate was used in the surgical treatment of humeral nonunion.

Collagen X Longitudinal Fracture Biomarker Suggests Staged Fixation in Tibial Plateau Fractures Delays Rate of Endochondral Repair

OBJECTIVES

To use a novel, validated bioassay to monitor serum concentrations of a breakdown product of collagen X in a prospective longitudinal study of patients sustaining isolated tibial plateau fractures. Collagen X is the hallmark extracellular matrix protein present during conversion of soft, cartilaginous callus to bone during endochondral repair. Previous preclinical and clinical studies demonstrated a distinct peak in collagen X biomarker (CXM) bioassay levels after long bone fractures.

SETTING

Level 1 academic trauma facility.

PATIENTS/PARTICIPANTS

Thirty-six patients; isolated tibial plateau fractures.

INTERVENTION

(3) Closed treatment, ex-fix (temporizing/definitive), and open reduction internal fixation.

MAIN OUTCOME MEASUREMENTS

Collagen X serum biomarker levels (CXM bioassay).

RESULTS

Twenty-two men and 14 women (average age: 46.3 y; 22.6-73.4, SD 13.3) enrolled (16 unicondylar and 20 bicondylar fractures). Twenty-five patients (72.2%) were treated operatively, including 12 (33.3%) provisionally or definitively treated by ex-fix. No difference was found in peak CXM values between sexes or age. Patients demonstrated peak expression near 1000 pg/mL (average: male-986.5 pg/mL, SD 369; female-953.2 pg/mL, SD 576). There was no difference in peak CXM by treatment protocol, external fixator use, or fracture severity (Schatzker). Patients treated with external fixation (P = 0.05) or staged open reduction internal fixation (P = 0.046) critically demonstrated delayed peaks.

CONCLUSIONS

Pilot analysis demonstrates a strong CXM peak after fractures commensurate with previous preclinical and clinical studies, which was delayed with staged fixation. This may represent the consequence of delayed construct loading. Further validation requires larger cohorts and long-term follow-up. Collagen X may provide an opportunity to support prospective interventional studies testing novel orthobiologics or fixation techniques.

LEVEL OF EVIDENCE

Level II, prospective clinical observational study.

Reliability of RUST and Modified RUST Scores for the Evaluation of Union in Humeral Shaft Fractures Treated with Different Techniques

BACKGROUND

The study aimed to evaluate the agreement between the radiographic union scale (RUST) and modified RUST (mRUST) in humeral shaft fractures treated with different techniques, and the effect of surgeons' experience and thresholds for determining bone union.

MATERIALS AND METHODS

A total of 20 orthopedic surgeons reviewed and scored radiographs of 30 patients with humeral shaft fractures treated by external fixation, intramedullary nailing, and plating using the RUST and mRUST on the 0 day, 6 weeks, 12 weeks and 24 weeks follow-up radiographs. Bone healing, interrater agreement between RUST and mRUST scores, and the threshold for radiographic union were evaluated.

RESULTS

The intraclass correlation coefficient (ICC) was slightly higher for the mRUST score than the RUST score (0.71 versus [vs.] 0.67). There was substantial agreement between the mRUST and RUST scores for external fixation (0.75 and 0.69, respectively) and intramedullary nailing (0.79 and 0.71); there was moderate agreement between them for plating (0.59 and 0.55). Surgeons with varying experience had a similar agreement for both scores and scores for each humeral cortex. The external fixation and intramedullary nailing group had higher RUST and mRUST scores than the plating group. The ICC for union was substantial (0.64; external fixation: 0.68, intramedullary nailing: 0.64, and plating: 0.61). More than 90% of the reviewers recorded scores of 10/12 for RUST and 13/16 for mRUST at the time of union.

CONCLUSIONS

RUST and mRUST scores can be used reliably for the evaluation of bony union in humeral fractures treated with an external fixator and intramedullary nailing. In cases of humeral plating, a more sensitive tool for evaluation of fracture union is needed.

Scoring of radiographic cortical healing with the radiographic humerus union measurement predicts union in humeral shaft fractures

PURPOSE

The purpose of this study is to determine if the radiographic humerus union measurement (RHUM) is predictive of union in humeral shaft fractures treated nonoperatively.

METHODS

All patients with long bone fracture nonunion presenting to a single surgeon were enrolled in a prospective registry. This registry was queried to identify patients with humeral shaft fractures treated nonoperatively and developed nonunion. The nonunion cohort was matched to a three to one gender- and age-matched control group that were treated nonoperatively for a humeral shaft fracture and achieved union. Two fellowship-trained orthopedic traumatologists blinded to eventual union scored radiographs obtained 12 weeks after injury using the RHUM. A binomial logistic regression determined the effect of the RHUM on the likelihood of developing union.

RESULTS

Nine patients with humeral shaft fractures treated nonoperatively with radiographs 12 weeks after injury that developed nonunion were identified. These patients were matched to 27 controls. Logistic regression demonstrated the RHUM was a significant predictor of healing 12 weeks after humeral shaft fracture treated nonoperatively (p = 0.014, odds ratio 9.434, 95% CI for OR 1.586-56.098). All patients with RHUM below 7 went on to nonunion. All patients with RHUM above 8 healed. Three of seven patients (43%) with RHUM of 7 or 8 healed.

CONCLUSION

The RHUM demonstrated an increased likelihood of achieving union 12 weeks after injury. Orthopedic surgeons can counsel patients that fractures with RHUM scores of 6 or below are in danger of developing nonunion and can target interventions appropriately.