The choice of osteosynthesis method for intra-articular fractures of the proximal epiphysis of the humerus.

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Introduction. Fractures of the proximal humerus, according to modern Russian literature, account for 5 to 15% of injuries to the bones of the human skeleton, and in 15% they are accompanied by dislocation of fragments [1], with age, the frequency of such fractures increases, and in patients older than 65 years, they are in third place in frequency after damage to critical zones of osteoporosis – proximal femur and distal epiphysis of the radius [2]. Despite many studies proving the ineffectiveness of non-surgical methods of treating fractures of the buttocks, work in this direction is carried out constantly. Modification of functional methods of treatment based on the method of V.V.Gorinevskaya and E.F.Dreving (1938-1945) is carried out, which is based on the exact primary reposition of fragments and early therapeutic gymnastics (from the first days of injury). According to the method of "gradual" self-reposition of fragments developed by D.P.Pokhvashchev et al. using three periods of physical therapy [3], mostly good and satisfactory results were achieved in more than 78% of cases. However, most studies of conservative methods do not note success in the treatment of intra-articular fractures of the butt. The dominant point of view at the moment is the opinion that conservative treatment of unstable, multifragmental fractures of the proximal humerus in most cases leads to unsatisfactory results [4].
The tactics of surgical treatment of fractures of the proximal humerus are represented by three main directions: bone osteosynthesis with plates with angular stability, intramedullary blocking osteosynthesis with various modifications of proximal shoulder nails (PHN), and shoulder joint replacement (hemi- and total). In parallel with the main methods, there are original author's fixators that have a limited prevalence. Transosseous osteosynthesis of POPC fractures is not widespread due to the technical complexity and the need for constant monitoring of the condition of the AVF.
Intramedullary osteosynthesis is possible for all types of fractures of the proximal humerus, as well as in cases of combined fractures of the neck and shoulder diaphysis, thanks to an improved screw locking system. This method of osteosynthesis is the method of choice in patients of older age groups, as it provides sufficient stability of fragments, surpassing the results of other methods of internal fixation. The indicators of restoration of function are higher in the group of patients who underwent intramedullary osteosynthesis [5].
Lockable fixation systems with angular stability have higher internal stability indicators, therefore they better retain the reposition at the stage of postoperative functional treatment [6]. Kogan P.G. and co-authors [7] in 2013 considered closed intramedullary osteosynthesis with proximal blocked rods to be one of the most promising methods of treatment of comminuted fractures of the proximal humerus. However, with the development of minimally invasive techniques, studies have appeared, where the negative sides of closed fracture reposition with blocking osteosynthesis are also mentioned.
The treatment tactics for 3- and 4-fragmentary fractures, taking into account the possible development of avascular necrosis of the humerus head in these patients, remains a controversial issue. Due to technical difficulties, the restoration of anatomical relations with a closed reposition, there are methods of "repositioning from a mini-access with soft-tissue stabilization of the tubercles" [8], or fixing the tubercles with metal structures separate from the main (lockable nail). The addition of stabilization of the fragments of the POPC by the "screw-in-screw" technique to some extent solves the problem of secondary displacement of fragments, however, it is inferior in reliability to bone osteosynthesis by the LCR plate.
Often, primary shoulder joint replacement is considered to be the tactic of choice for multifragmental fractures of the proximal humerus. The basic principles of unipolar endoprosthetics of the shoulder joint were first outlined by Neer C.S. in the 70s of the twentieth century. Today, endoprosthetics has gone far ahead, introducing a new generation of implants. Most recent reports show that primary arthroplasty is usually preferable to arthroplasty in the long term, since the primary operation is technically easier to perform [9]. However, U. Prakash et al. (2002) found no difference between primary and delayed endoprosthetics after more than 30 days after injury [10]. To date, in the domestic and foreign literature devoted to the study of methods of treatment of intra-articular fractures of the proximal humerus, the question of "osteosynthesis or prosthetics of the shoulder joint" is one of the most relevant.
Recently, there have been more and more reports of unsatisfactory results of shoulder joint replacement in fractures of the proximal humerus. D. Den Hartog in 2010 published the results of a meta-analysis of 33 studies that included data on the results of treatment of 1096 patients with three- and four-fragmental fractures of the proximal humerus. The patients who underwent endoprosthetics had the worst functional result compared to the non-operated patients, with a difference of 10.9 points on the 100-point Constant scale [11]. In a comparative study of the long-term consequences of treatment of patients with three- and four-fragmental fractures who underwent endoprosthetics, moderate and severe impairment of limb function was noted in up to 30% of cases [12].Despite the ambiguity of the results obtained for prosthetics of the shoulder joint in fractures, currently the prevailing opinion is that intra-articular fractures of the proximal humerus are an indication for primary joint replacement, since anatomical restoration and the creation of conditions for reparative regeneration by osteosynthesis methods are not possible [13]. In addition to technical difficulties, in the case of osteosynthesis of intra-articular fractures of the humerus head, the long-term result is always doubtful due to a violation of its vascularization at the time of injury and surgical aggression, which then lead to necrosis of the head and collapse, which occurs from 30% to 100% of cases after three- and four-fragmental fractures [14]. Thus, one of the main factors influencing the choice of the surgical aid method in the case of intra-articular fractures of the POPC is the degree of possible post-traumatic and iatrogenic ischemia of bone tissue with an outcome in ANGPC. To assess the likelihood of developing this complication and an objective choice of treatment method, it is necessary to take into account the probability of damage to the main sources of blood supply to the head of the humerus.
From additional studies of the vascular network of the POPC, it was found that the blood supply to the head of the humerus is carried out mainly through the arcuate artery, which branches off from the ascending branch of the anterior envelope of the shoulder artery. This artery sinks into the humerus in the inter-tubercle furrow, giving branches to both tubercles and the head. If the arcuate artery is damaged, the blood supply to the head cannot be compensated by other sources, which leads to avascular necrosis of the humerus head [15].
The fundamental importance of damage to the arched artery is confirmed by CH Brooks et al., who studied the anatomy of the arteries of the POPC and the effect of four-fragmental fractures on the blood supply to the head of the humerus using perfusion with barium sulfate of 16 cadaveric preparations. The main arterial supply to the head of the humerus was carried out through the ascending branch of the anterior brachial envelope artery and its intraosseous continuation, the arcuate artery. There were significant intraosseous anastomoses between the arched artery and: 1) the posterior brachial envelope artery through the vessels entering the posteromedial part of the proximal humerus; 2) metaphysical vessels; and 3) vessels of the large and small tubercles. In most cases, simulated four-fragmental fractures stopped perfusion of the humerus head. However, if the fragment of the head passed distally below the articular surface and medially, some perfusion of the head was preserved due to the posteromedial vessels. These vessels play an important role in the treatment of comminuted fractures of the proximal humerus [16].
Thus, clinical and experimental data indicate violations of vascularization with subsequent necrosis of the head in 30-100% of cases after comminuted intra-articular fractures consisting of 3 and 4 fragments, as a result of which the outcomes of osteosynthesis are not always satisfactory, since avascular necrosis develops against the background of age-related changes in the blood supply to the head of the humerus and circulatory disorders as a result of trauma, and then osteoarthritis of the shoulder joint [17]. Based on this, there is a need to stimulate reparative osteogenesis in intra-articular injuries to shorten the time to achieve fusion and prevent ischemic changes in the head of the humerus. The use of proprietary autotransplants seems to be the most promising for the stimulation of osteogenesis.
The use of a non-free musculoskeletal graft from the cranial process of the scapula on the feeding leg of the short head of the biceps muscle of the shoulder mainly appears in the correction of instability of the shoulder joint (Latarge operation). At the same time, the blood supply of the osteotomized fragment of the coracoid was proved by anatomical and morphological examination [18]: anatomical cadaveric and clinical studies demonstrated the presence of a previously unidentified direct arterial branch from the second (middle) part of the axillary artery feeding the anterior 2-3 cm of the cranial process of the scapula.
In the study of the extracortical arterial blood supply network of the coracoid, performed by Antoine and Olivier Hamel, postmortem arteriography of the upper limb was performed. Results: the vertical part of the cranial process was supplied with the supracapular artery, and the horizontal part with branches of the axillary artery [19]. In another study of the blood supply of the cranial process, conducted by Zhenhan Deng and co-authors, it was revealed that the cranial process is a structure with a rich blood supply (Fig. 1.)
It was found that the KO is supplied by the supra-scapular artery, the thoracic-acromial artery and a branch from the second part of the axillary artery. After the coracoid osteotomy procedure, no artery from m was found.biceps penetrating at the place of its attachment. In only one sample, a blood vessel obtained by computed tomography penetrated the bone graft from the lower side. Thus, there is a possibility that the vessels obtained from m.biceps, nourished the underside of the beak process [20].
Thus, the problem of choosing the optimal method of surgical aid aimed at stabilizing the fragments and simultaneously restoring blood supply to the separated epiphysis of the proximal humerus with the risk of angina remains open, which served as the basis for this scientific study.
The aim of our study is to improve the results of surgical treatment of intra-articular fractures of the proximal humerus on the basis of the development of a new osteosynthesis technique with the transposition of a blood-supplied bone fragment of the cranial process of the scapula into the fracture zone of the proximal shoulder with a high risk of ANGPC.Materials and methods. A retro- and prospective analysis of 67 observations of patients with intra-articular fractures of the proximal humerus, namely categories 11-C1 and 11-C2, who were treated inpatient in the department of emergency Traumatology of the State Medical Institution NSO GKB No. 1, was carried out.Novosibirsk, and subsequently observed on an outpatient basis. The criteria for inclusion in the study group were the following parameters: male or female patients, aged 20 to 80 years inclusive, with diagnosed fractures of type C to AO (C1-C2) or with the consequences of fractures of the proximal humerus, requiring surgical treatment. Out of the total number of patients, two groups were formed: a retrospective (35 patients), using traditional surgical methods in the treatment (bone osteosynthesis with a plate with angular stability or intramedullary blocked osteosynthesis with proximal shoulder pins), and a study group (32 patients), in the treatment of which the method of transplantation into the fracture zone of non-free musculoskeletal graft from the cranial process of the scapula. Both groups of patients were examined in the preoperative and postoperative periods using the following methods: clinical (anamnesis, complaints, local status); intraoperative monitoring data, X-ray (radiographs of the shoulder joint in 2 or 3 projections); MRI and MSCT of patients (assessment of the degree of osteosclerosis and concomitant dystrophic changes and/or injuries VMP tendons, the degree of development of secondary omarthrosis), histological (study of the severity of postoperative ischemic disorders of the bone tissue of the humerus head). The X-ray dynamics of changes in the fracture zone and the bone structure of the humerus head were studied in patients.
As part of the study, a morphological study of 8 preparations of a bone-muscle graft consisting of a part of the muscular abdomen of the biceps of the shoulder, a tendon of the short head of this muscle, and an apical fragment of the cranial process of the scapula up to 1 cm was carried out to study the presence of a vascular network in the area of the transition of the bone fragment of the cranial process of the scapula into the tendon and the muscular part of the short head of the biceps of the shoulder.
Results.
Sample distributions of continuous indicators of age, height, weight, time of examination after surgery, PS, ADL, ASES, retraction, flexion, ext. and nar. rotations were investigated for agreement with the law of normal distribution by the Shapiro-Wilk criterion, equality of variances in the compared groups was investigated by the Fisher criterion. Most of the distributions turned out to be abnormal and heteroscedastic, so the comparison was carried out by the nonparametric Mann-Whitney U-criterion. To estimate the magnitude of the difference in the groups, a pseudo median of value differences (PMED) and a standardized mean difference (SRS) were calculated. Continuous indicators were described as: median [first quartile: third quartile] (MED [Q1; Q3], mean ± standard deviation (MEAN ± CO), minimum and maximum values (MIN - MAX).
Binary indicators of consolidation and elevation were described as the number of events and frequencies with the construction of a 95% confidence interval according to the Wilson formula (n, % [95%CI]). To assess the difference between the groups, the risk difference (PP) and the odds ratio (OR) with 95% CI were calculated. For the degrees of categorical indicators of ANGP, the number of patients and frequency (degree - n (%)) were calculated. Binary and categorical indicators were compared by Fisher's exact two-way criterion. When comparing degrees in categorical indicators, the correction of the error of multiple comparison by the Benjamin-Hochberg criterion was carried out.
Statistical hypotheses were tested at a critical significance level of p = 0.05, i.e. the difference was considered statistically significant if p < 0.05.
All statistical calculations were carried out in the Rstudio program (version 2022.07.2+576, 2022-09-06, America) in the R language (version 4.1.3, Austria).
The distribution of degrees of ANGP in groups 1 and 2 was statistically significantly different (p = 0.020), namely, 0 degrees in 12 (48%) and 19 (86.4%) patients, respectively (p = 0.021), 4 degrees in 10 (40%) and 2 (9.1%) patients, respectively (p = 0.031). There were no differences in the 3rd degree of ANGP (p = 0.611) (Fig. No. 2).
The volume of active movements in groups 1 and 2 was within comparable limits, in group 2 on average by 5-10 units. (degrees) it was statistically significantly lower (p = 0.504-0.422) (Fig.3).
The ADL, PS scores and the total ASES score in groups 1 and 2 were within 45 [35; 50] and 45 [45; 50] units. accordingly, in group 2, on average, 5 units of measurement. it was statistically significantly higher (p = 0.024) (Fig.4).
Consolidation of the fracture in the control group was noted in 92% of cases, Consolidation (p-level 0.491), the remaining 8% had an outcome in the form of a false joint of the anatomical or surgical neck of the humerus within 6 months after surgery. In the study group, the development of a false joint was noted in 4.3%, in other cases, fractures consolidated.
Discussion.
Modern methods of stimulation of reparative processes, which are most accessible for implementation in a multidisciplinary hospital, are considered. The use of free spongy bone autografts from the iliac wing in the bulk of publications is considered exclusively for the replacement of defects in the proximal shoulder that occur due to the crushing of the osteoporotic bone at the time of injury. This variant of bone grafting is optimal in many parameters, including the absence of an immune response, the presence of living osteogenic stromal cells. The main disadvantages of autoplasty are well known to any practicing traumatologist: causing additional trauma to the donor site, lengthening the operation time, and the appearance of additional infection gates. Some sources indicate the possibility of using allokost and synthetic materials for the same purpose. Unfortunately, these materials cannot stimulate osteogenesis in any way in the area of bone ischemia, except in cases of saturation of the bone structure of the allograft with osteostimulating substrates. An example is a study on the study of osteostimulation of a graft from a preparation of the head, neck and part of the fibular diaphysis of a cadaver saturated with a collagen solution. According to the results of the work, the developed combined allogeneic fibular head graft, saturated with type I collagen, is non-toxic, has no immunogenicity, and at the same time has more pronounced osteoconductive properties compared to native bone allografts, which contributes to its colonization by cells [21]. The widespread use of autologous platelet-enriched plasma, autologous human platelet lysate and autologous human bone marrow aspirate has limited use due to the use of special expensive equipment. The most promising for the stimulation of osteogenesis is the use of non-free autografts that preserve the blood supply to the parafracture area from an additional source. In addition to the proposed technique, the method of non-free bone grafting for the treatment of false joints in the upper third of the humerus attracts attention from available sources [22]. The essence of the method is the formation of a musculoskeletal graft, including a fragment of the lower corner of the scapula, which is moved to the reconstruction zone in the upper third of the shoulder.
Based on the results of the study, the following conclusions are made:
Indications for osteosynthesis are intra-articular fractures of the buttocks with a displacement of fragments along the inter-tubercular furrow of more than 2 mm. The indication for bone osteosynthesis without using the method should be considered fractures without violating the integrity of the interbugoreal furrow.
The use of blocking osteosynthesis in intra-articular fractures of the butt is significantly hampered by the need to reposition the head and the tubercle zone. At the same time, in the case of blocking osteosynthesis, the rigidity of fixation of fragments decreases, which can contribute to their secondary displacement. Given the closed nature of the reposition of fragments, the probability of damage to the arcuate branch of the anterior envelope of the shoulder artery increases.
Indications for shoulder joint replacement in intra-articular fractures type C1 and C2 are: unconsolidated long-standing fractures and false joints accompanied by chronic pain syndrome; intra-articular injuries accompanied by fragmentation of the articular surface; intra-articular fractures of the proximal shoulder in patients with diabetes mellitus. In other cases, primary osteosynthesis of the humerus is preferred when deciding on treatment tactics.

About the authors

Yuri Afanasiev

City Clinical Hospital No. 1

Author for correspondence.
Email: aua315@icloud.com
ORCID iD: 0000-0003-1134-1524

trauma and orthopedic surgeon

Russian Federation, Russia, 6, Zalessky st, Novosibirsk, Russia, 630091

References

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