Catastrophic failure of a titanium locking plate in a proximal humeral fracture: case report and literature review

Therapeutic effect of titanium locking plate combined with suture anchor repair in proximal humeral fractures

Objective

To explore the therapeutic effect of titanium locking plate combined with suture anchor (SA) repair in the treatment of proximal humeral fractures (PHF).

Methods

This retrospective study was conducted by analyzing the clinical data of 113 patients with PHF admitted to Wuhan Fourth Hospital from March 2021 to October 2023. Among them, 55 patients underwent open reduction and internal fixation (OR/IF) using titanium locking plate (OR/IF group), and 58 patients underwent surgery with titanium locking plate combined with SA (SA group). Perioperative condition, treatment success rate, shoulder joint function before and after the surgery, shoulder joint range of motion, and incidence of complications were compared between the groups.

Results

Surgery duration and the length of hospital stay of patients in the SA group were significantly shorter than those in the OR/IF group, and the intraoperative blood loss was significantly lower in the SA group than in the OR/IF group (P<0.05). In terms of treatment effect, the SA group was significantly higher than the OR/IF (P<0.05). After the surgery, muscle strength, pain levels, daily living activities, and shoulder joint range of motion scores of both groups improved, and the improvement was more significant in the SA group compared to the OR/IF group (P<0.05). After the surgery, the degrees of internal rotation, forward flexion, backward extension, and external rotation of the shoulder joints in both groups increased compared to pre- surgery levels, and were greater in the SA group compared to the OR/IF group (P<0.05). The incidence of complications in the SA group was lower than that in the OR/IF group (P<0.05).

Conclusions

In patients with PHF, the combination of titanium locking plate and SA has a more significant therapeutic effect than that of titanium locking plate alone, which is associated with improved shoulder joint function and range of motion, and reduced incidence of complications.

Biomechanical design optimization of proximal humerus locked plates: A review

BACKGROUND

Proximal humerus locked plates (PHLPs) are widely used for fracture surgery. Yet, non-union, malunion, infection, avascular necrosis, screw cut-out (i.e., perforation), fixation failure, and re-operation occur. Most biomechanical investigators compare a specific PHLP configuration to other implants like non-locked plates, nails, wires, and arthroplasties. However, it is unknown whether the PHLP configuration is biomechanically optimal according to some well-known biomechanical criteria. Therefore, this is the first review of the systematic optimization of plate and/or screw design variables for improved PHLP biomechanical performance.

METHODS

The PubMed website was searched for papers using the terms "proximal humerus" or "shoulder" plus "biomechanics/biomechanical" plus "locked/locking plates". PHLP papers were included if they were (a) optimization studies that systematically varied plate and screw variables to determine their influence on PHLP's biomechanical performance; (b) focused on plate and screw variables rather than augmentation techniques (i.e., extra implants, bone struts, or cement); (c) published after the year 2000 signaling the commercial availability of locked plate technology; and (d) written in English.

RESULTS

The 41 eligible papers involved experimental testing and/or finite element modeling. Plate variables investigated by these papers were geometry, material, and/or position, while screw variables studied were number, distribution, angle, size, and/or threads. Numerical outcomes given by these papers included stiffness, strength, fracture motion, bone and implant stress, and/or the number of loading cycles to failure. But, no paper fully optimized any plate or screw variable for a PHLP by simultaneously applying four well-established biomechanical criteria: (a) allow controlled fracture motion for early callus generation; (b) reduce bone and implant stress below the material's ultimate stress to prevent failure; (c) maintain sufficient bone-plate interface stress to reduce bone resorption (i.e., stress shielding); and (d) increase the number of loading cycles before failure for a clinically beneficial lifespan (i.e., fatigue life). Finally, this review made suggestions for future work, identified clinical implications, and assessed the quality of the papers reviewed.

CONCLUSIONS

Applying biomechanical optimization criteria can assist biomedical engineers in designing or evaluating PHLPs, so orthopaedic surgeons can have superior PHLP constructs for clinical use.