Mismatch of AO anatomically shaped distal humeral plate with humeral shaft forward flexion angulation in adult Chinese population

CT-based measurement and analysis of distal humerus morphology in healthy adults from Northern China

BACKGROUND

This study aims to investigate the morphological characteristics of the distal humerus in healthy adults from northern China using computed tomography and three-dimensional reconstruction techniques and compared whether there were diferences in morphology among populations from diferent geographical regions.

METHODS

The CT data of 80 patients were imported into Mimics software for three-dimensional reconstruction and measurement. The differences in distal humeral morphological parameters between different genders and sides were compared, and the correlation between the parameters was explored. The distal humeral morphological parameters between Western and Chinese populations based on current and previous pooled results were compared.

RESULTS

Thirty-one morphological parameters were measured and analyzed in this study. The average (and standard deviation) of capitellum depth, capitellum width, capitellum height, distal humerus width, epitrochlea width, and humeral metaphyseal width was 10.83 ± 1.18 mm, 17.60 ± 2.06 mm, 21.10 ± 2.03 mm, 44.38 ± 4.07 mm, 12.02 ± 1.90 mm and 58.95 ± 4.86 mm, these parameters were significantly higher (P < 0.001*) in males than females. The capitellum width (r = -0.300, P = 0.007*), anterior lateral trochlear depth (r =-0.227, P = 0.043*), medial crest coronal tangential angle (r = 0.307, P = 0.006*), olecranon fossa volume (r = -0.408, P < 0.001*), olecranon fossa surface area (r = -0.345, P = 0.002*) and coronoid fossa surface area (r = -0.279, P = 0.012*) were significantly correlated with the age of the subjects. In the comparison of people from different regions, the capitellum height, lateral trochlear high, trochlear groove high, trochlear depth and medial trochlear high of the Western population were 23.25 ± 2.56 m, 21.6 ± 2.20 mm, 17.8 ± 2.00 mm, 17.80 ± 2.00 mm, 29.9 ± 4.10 mm, are significantly higher than those in the Chinese population. while capitellum width (15.55 ± 2.68 mm) and capitellum depth (9.00 ± 1.00 mm) were slightly lower.

CONCLUSION

The findings provide a basis for the design of distal humeral orthopaedic implants, ensuring greater alignment with the anatomical structure of the distal humerus and improved surgical outcomes. Furthermore, the study provides a reference point for the diagnosis and classification of distal humeral diseases, as well as guidance for patient rehabilitation.

Risk factors for hardware-related complications after extra-articular distal humerus fracture fixation using an anatomical locking plate

PURPOSE

We aimed to identify the incidence and risk factors of hardware-related complications in patients treated with anatomical locking plate fixation for extra-articular distal humerus fractures.

METHODS

From 2013 to 2020, patients with extra-articular distal humerus fractures who underwent open reduction and internal fixation with an extra-articular distal humerus locking plate (EADHP) were retrospectively reviewed and categorized according to the presence/absence of hardware-related complications. Hardware-related complications were defined as the occurrence of skin prominence on the plate and discomfort in activities of daily living. Patient demographics, the lateral condylar angle, lateral body length, shaft-condylar angle of the humerus, and plate length were analyzed.

RESULTS

Of the 29 patients, 10 (34%) did not develop hardware-related complications (group A), whereas 19 (66%) did (group B). Patient demographics did not differ between the groups. However, the number of patients who underwent hardware removal was significantly greater in group B (16/19) than in group A (4/10; p = 0.032). Radiologic assessment revealed no significant difference in the lateral condylar or shaft-condylar angle. However, the lateral body length was greater in group A than in group B (44.5 ± 4.8 vs. 39.5 ± 3.7, p = 0.007). The plate length significantly differed between the groups. Twelve of 19 (63%) patients in group B received short-hole plates (six holes), while nine of ten (90%) patients in group A received long-hole plates (eight holes). In the multivariable analysis, the lateral body length of the distal humerus (p = 0.047, odds ratio = 0.734, 95% confidence interval: 0.542-0.996) and plate length (p = 0.036, odds ratio = 0.076, 95% confidence interval: 0.542-0.996) were associated with hardware-related complications.

CONCLUSIONS

Most patients developed hardware-related complications, particularly with short plates, mainly because of the narrow lateral body length of the distal humerus. Surgeons should be careful to secure EADHP in the appropriate position, especially when short plates are used in patients with narrow lateral body length.

Anatomic fit of precontoured extra-articular distal humeral locking plates: a cadaveric study

Background

Extra-articular distal humerus locking plates (EADHPs) are precontoured anatomical plates widely used to repair distal humeral extra-articular diaphyseal fractures. However, EADHPs frequently cause distal protrusion and resulting skin discomfort. The purpose of this study was to predict the occurrence of anatomic fit mismatch. We hypothesized that the smaller the humerus size, the greater the anatomic fit mismatch with EADHP.

Methods

Twenty humeri were analyzed in this study. Humeral length and distal humeral width were used as parameters of humeral size. Plate protrusion was measured between the EADHP distal tip and the distal humerus. We set the level of unacceptable EADHP anatomic fit mismatch as ≥10 mm plate protrusion.

Results

A significant negative linear correlation was also confirmed between humeral size and plate protrusion, with a coefficient of determination of 0.477 for humeral length and 0.814 for distal humeral width. The cutoff value of humeral length to avoid ≥10 mm plate protrusion was 293.6 mm (sensitivity, 88.9%; specificity, 81.8%) and for distal humeral width was 60.5 mm (sensitivity, 100%; specificity, 81.8%).

Conclusions

Anatomic fit mismatch in distal humeral fractures after EADHP fixation has a negative linear correlation with humeral length and distal humeral width. For patients with a distal humeral width <60.5 mm, ≥10 mm plate protrusion will occur when an EADHP is used, and an alternative implant or approach should be considered.

Automatic estimation of morphological characteristics of proximal tibia for precise plate treatment using model matching

Plate treatment is currently the standard treatment of proximal tibia fracture. Morphological characteristics can help orthopedic surgeons understand anatomic information of tibia and choose well-matched plate for reducing difficulties in plate treatment. However, manual measurement of morphological characteristics of patient's tibia is time-consuming and labor-intensive. Therefore, this study proposes an automatic method to accurately estimate the morphological characteristics of patient's tibia for assisting plate treatment. In the off-line stage, an average shape with typical characteristics was computed from 422 tibia models, and the morphological characteristics of the average shape were measured by the orthopedic surgeon. In the on-line stage, the point's correspondence between the average shape and every tibia model was created by the proposed morphable model matching method firstly. Then, the morphological characteristics of tibia for every patient were estimated automatically based on the point's correspondence and characteristics of average shape. The effectiveness of the method was validated by comparing the manual measured and automatic-estimated characteristics. In addition, the basic experiments of virtual and real plate implantation preliminarily confirmed that the automatic-estimated morphological characteristics were helpful for plate treatment. In all, we propose an automatic and accurate estimation method of morphological characteristics for a large-scale library of Chinese tibia models, which provides orthopedic surgeons with scientific and quantitative description of tibia.

Preliminary exploration of a quantitative assessment index for the matching performance of anatomical bone plates using computer

BACKGROUND

To explore a new quantitative index to assess the matching performance of anatomical bone plates using digital technology.

METHODS

CT data of normal tibias of 40 adults were collected. Two brands of medial distal tibia plates were digitized. Two trained orthopedists simulated the surgical operation in Rhino 5.1 software by placing the plate curve on the medial distal tibia surface. The volume of the interstice between the plate curve and the bone surface was measured. The inverse value of this average interstice distance was used as the matching performance index (MPI). A wall thickness analysis tool was used to mark various interstice distances with varied colors.

RESULTS

The Kangli medial distal tibia plate had a MPI of 0.55 ± 0.08 by operator A and 0.55 ± 0.06 by operator B. The general care medial distal tibia plate had a MPI of 0.32 ± 0.06 by operator A and 0.31 ± 0.05 by operator B. There were significant variations in the MPI between the two types of plates by both operators (p < 0.001). And significant variations were observed in the MPI of general care medial distal tibia plates among various operator groups (p = 0.028).

CONCLUSION

This quantitative index of matching performance is straightforward and intuitive. However, we still need a method to improve the experimental repeatability, especially when it comes to a plate with poor matching performance.

Functional outcome of extra-articular distal humerus fracture fixation using a single locking plate: A retrospective study

PURPOSE

The optimal method for fixation of extra-articular distal humerus factures poses a management dilemma. Although various plate configurations have been proposed, anatomic shaped extra-articular distal humerus locking plates have emerged as a viable solution for these complex injuries. We assessed clinico-radiologic outcome in our retrospective case series of extra-articular distal humerus fractures managed with these plates.

METHODS

Forty-five patients of extra-articular distal humerus fractures, who were operated at our level 1 trauma centre between January, 2012 and December, 2016, were identified. After exclusion, 36 patients were available for the final assessment. All patients were operated with the triceps-reflecting modified posterior approach. Regular clinico-radiologic follow-up was done evaluating elbow functionality, fracture union, secondary displacement, non-union, implant failure and any complications; Mayo Elbow Performance score (MEPS) was used for the final functional assessment.

RESULTS

Twenty-four (66.7%) male and 12 (33.3%) female patients constituted the study group, who had an average follow-up of 15 months. Preoperatively three patients and post-operatively one patient had radial nerve palsy; all had neurapraxia and recovered completely. Overall, 34 (94.4%) patients were adjudged to have complete radiological union within 3 months; 2 (5.5%) patients developed non-union. Mean flexion achieved was 122.9° ± 23°, and mean extension was -4.03° ± 6.5°; 1 patient with head injury developed flexion deformity of 45°. Average MEPS at the final follow-up was 90.8° ± 9.9°.

CONCLUSION

Stable reconstruction and early initiation of physiotherapy are utilitarian to envision optimal outcome; the use of precontoured extra-articular distal humerus locking plates has yielded satisfactory results with minimal complications in our hands.