This is the first report demonstrating the functional and radiological outcomes of the described ‘on-table’ reconstruction technique for treating Dubberley type 3 fractures. All fractures showed bony union with good functional outcome at the follow-up’s end, although one partial AVN occurred, constituting 10% of our cases.
The ‘on-table’ reconstruction technique for comminuted articular fractures was initially introduced in radial head fractures3, 8. A. Businger et al.3 reported 6 cases of Mason type 3 and type 4 radial head fractures using the ‘on-table’ reconstruction technique. 5 fractures were united, and 1 patient went on to radial head excision due to AVN of the radial head and pain of elbow. However, after the mean 9 years of follow-up, all showed good functional outcomes, the mean DASH score was 1.94 points, and the mean range of movement was 6°–141° at the elbow. The ‘on-table’ reconstruction technique we employed for comminuted articular fractures in the distal humerus also demonstrated satisfactory treatment outcomes similar to those reported in radial head fractures.
AVN after capitellum or trochlear fracture fixation was also reported in other studies. A recent meta-analysis by M. Heller et al.10 shows 12% of AVN in capitellar fractures. To be more specific with Dubberley type III fractures, Dubberley et al.6 reported 1 AVN in three patients with Dubberley type IIIA fractures and 2 AVNs in eight Type IIIB patients. Durakbasa et al.7 reported 4 AVNs out of 7 Dubberley type III patients. Compared to these studies, our result of an AVN rate of 10% is even better.
This relatively low rate of AVN could be stemmed in our limited approach. We use a lateral approach only, thus saving medial side soft tissue. Dubberley et al.6 and Durakbasa et al.7 also used a single posterior incision. Still, they dissected medially and laterally through this incision, which could interfere with circulation to the fracture site. Our single-sided approach is possible as we reduce outside the fracture site, not through the medial side.
We acknowledge that on-table reconstruction could harm the biological environment because fragments should be stripped off from the surrounding soft tissue. However, it is known that the blood supply to the capitellum and lateral trochlea comes mainly from the posterior condylar perforating vessels.20 This means separating the fragment from the anterior side may not harm the blood supply. This hypothesis is also supported by a meta-analysis published in 2023 by M. Heller et al.10 This study reported that when the screw is inserted at the capitellum from anterior to posterior, the mean AVN rate is 11%, which is lower than the mean AVN rate of 29% when the screw was inserted posterior to anterior.
On top of that, there is insufficient evidence that this AVN could lead to poor clinical outcomes. S. Mukohara et al.17 suggested that AVN may not be important, but whether the trochlear component can be reconstructed may be important. They reported that patients with three or more fragments of trochlea had worse clinical outcomes and ROM than those with fewer trochlear fragments. Our patient with AVN also showed fair results afterwards. From this point of view, we used our technique to reconstruct the trochlear component correctly.
Limitations
This study had several limitations. The value of our study may be limited by the small number of cases and the retrospective analyses of the data, which is susceptible to selection bias. Nevertheless, Dubberley type III, capitellum and trochlea fractures are rare, and the reported results are important for understanding and optimizing treatment options. Furthermore, there were no posterior comminution (type B) fractures. Our relatively good functional outcome and lower AVN could contribute to fewer extensive cases. A further study, including more severe cases, is needed to support our theory fully. Lastly, our results were limited to mid-term follow-up; further investigation with long-term follow-up is needed.