Introduction: String-of-Pearls (SOP) plate is considered advantageous for stabilizing comminuted
humeral fractures as it is easily contoured, has multi-dimensional screw placement
and high area moment of inertia. We hypothesize that SOP plate fixation of humeral
fractures results in good long-term outcomes.
Materials and Methods: Medical records of dogs undergoing SOP plate humeral fracture repair between 2015
and 2024 were reviewed and assessed for complications and long-term outcomes.
Results: Twenty-two dogs were included with predominantly closed (21) mid-diaphyseal (6) comminuted
(18) Y-T (6) fractures represented. Single (11) and double (11) plate fixation were
used. Minor complications occurred in 13.6%. Major complications occurred in 41% (9)
including implant failure in five dogs (screw [4] and olecranon osteotomy [1]) and
implant infection in 5/6 dogs requiring explantation. Anaesthesia times and plate:screw
ratios were similar in all dogs. All with infections received liposomal bupivacaine,
however, only 56% (9) without infection did. Long-term outcomes were assessed (mean:
155.7 weeks [12–341 weeks]). Half (11) showed no lameness, 9% (2) mild-moderate, and
36.4% (8) experienced severe mobility impairment due to major complications.
Discussion/Conclusion: We reject the hypothesis that humeral fracture repair with SOP plate leads to good
long-term outcomes. Over half experienced complications with a third of patients having
severe long-term mobility impairment. A high infection rate is suspected due to preexisting
soft tissue trauma and anaesthesia duration due to the complexity of the fractures.
All with infections received incisional liposomal bupivacaine, raising questions about
its use. Larger studies are needed to confirm these findings and compare them with
other implant systems.
Acknowledgment
None.
