Abstract
Background
This retrospective clinical study aims to compare the functional and radiological outcomes after open reduction and internal fixation versus minimally invasive plate osteosynthesis of unstable proximal humerus fractures treated with both locking plate and intramedullary graft.
Methods
Forty-seven patients with proximal humerus fractures were treated with either open reduction and internal fixation (25 cases) or minimally invasive plate osteosynthesis (22 cases) and evaluated retrospectively with a minimum follow-up of 12 months. Thirty-one fresh-frozen fibulae and 16 lyophilized tibia allografts were used for augmentation. Change of both neck-shaft angle and humeral head height were evaluated radiologically. Functional outcomes were assessed using Disabilities of the Arm, Shoulder and Hand Score (DASH), Absolute Constant–Murley Score (CSabs), Relative Constant–Murley Score (CSrel), and Individual Relative Constant–Murley Score (CSindiv).
Results
Follow-up period and age for open reduction and internal fixation/minimally invasive plate osteosynthesis were 27.4 ± 16.2/29.6 ± 17.6 months and 60.5 ± 13.7/66.3 ± 11.7 years. CSabs, CSrel, and CSindiv were 57.3 ± 21.2/52.4 ± 18.9, 73 ± 24.1/73.9 ± 23.4, and 69.6 ± 24.8/64 ± 25.5 for open reduction and internal fixation/minimally invasive plate osteosynthesis, p ≥ 0.409. DASH was 14.8 ± 12.5/18.7 ± 14.5 for open reduction and internal fixation/minimally invasive plate osteosynthesis, p = 0.324. Decrease of neck-shaft angle and humeral head height was 7.8 ± 9.4/8.2 ± 15.6° and 0.6 ± 5.5/1.4 ± 2.6 mm for open reduction and internal fixation/minimally invasive plate osteosynthesis, p ≥ 0.380. Surgical time was 165.8 ± 77.6/84.7 ± 38.1 min for open reduction and internal fixation/minimally invasive plate osteosynthesis, p < 0.001.
Conclusions
Locked plating with intramedullary graft augmentation of unstable proximal humerus fractures demonstrates similar functional and radiological outcomes when comparing open reduction and internal fixation with minimally invasive plate osteosynthesis. However, minimally invasive plate osteosynthesis is related to significantly shorter surgical time versus open reduction and internal fixation.
Keywords: Proximal humerus, locking plate, augmentation, intramedullary graft, minimally invasive plate osteosynthesis, open reduction and internal fixation
Introduction
Proximal humerus fractures (PHFs) represent 53% of all shoulder girdle injuries. 1 In patients older than 65 years their incidence is ranked third, following distal radius and femoral neck fractures.2–4 Although only 20% of these fractures are unstable and require surgical treatment, 5 the expected increase in their incidence by year 2030 will result in a higher number of corresponding surgical procedures.3,6 Among the variety of existing fixation methods, locking plate (LP) fixation has become the gold standard for treatment of unstable PHFs. 7 However, locked plating is still associated with a high rate of complications and reoperations, mostly due to varus collapse, screw penetration in the glenohumeral joint, and avascular necrosis (AVN) of the humeral head.8,9 Most authors suggest that these complications are related to fracture type and morphology (3- and 4-part fractures according to Neer Classification, 5 additional medial comminution, 10 osteoporosis, 11 initial varus displacement,12,13, and indicators for ischemic changes 14 ), inability to obtain anatomical or nearly anatomical reduction15,16, and LP rigidity.9,11
Intramedullary grafts (IMGs) are able to recreate missing medial support by filling in osteoporotic defects and withstanding deforming rotator cuff forces and moments. 17 In a pilot study, Gardner et al. 17 enhanced the stability of LP constructs by adding intramedullary fibular allograft in 7 cases of unstable PHFs with medial calcar deficiency and/or osteoporosis, demonstrating no complications. Their promising results have leveraged the interest towards biomechanical18–22 and clinical studies23–36 focusing on treatment of unstable PHFs with simultaneous locked plating and intramedullary grafting. While most of these authors perform open reduction and internal fixation (ORIF), there is still a lack of reports on fixation of unstable PHFs using both LP and IMG with minimally invasive plate osteosynthesis (MIPO) technique. Furthermore, to our knowledge, there is no existing study comparing the two techniques—ORIF versus MIPO—in presence of allograft augmentation.
Therefore, the aim of this retrostpective clinical study was to compare the functional and radiological outcomes after ORIF versus MIPO of unstable PHFs treated with both LP and IMG.
Materials and methods
Ethics
This study was conducted in accordance with the principles of the Declaration of Helsinki as well as national legal and regulatory requirements. It was retrospectively registered and approval was granted by the local Ethics Committee of the authors' institution (No. EC–01/26.01.2023).
Patients
All surgical procedures were performed by 8 senior trauma surgeons. All patients were treated with simultaneous locked plating and intramedullary grafting at a level 1 trauma center from January 2015 until November 2020. The inclusion criteria considered (a) patients aged 18 years or older, (b) patients with nonpathological and unstable PHFs according to the Neer criteria 5 (displacement of more than 1 cm and/or angulation of more than 45°), (c) patients with PHFs having additional features of instability and complexity such as medial comminution, osteoporosis and/or initial varus displacement, (d) patients without history of a recent trauma to the contralateral shoulder, (e) time to surgery within 3 weeks. The exclusion criteria considered (a) patients under the age of 18 years, (b) patients with impaired shoulder function prior to the traumatic incident, (c) patients with pathological fractures, (d) open fractures, (e) fractures with a period longer than 3 weeks between injury and surgery.
Surgical technique
A standard beach chair position was used for all patients. In 25 of the cases, ORIF was performed through a deltopectoral approach. In the remaining 22 cases, MIPO technique was applied via either an anterolateral or a direct transdeltoid proximal window. A total of 31 fresh-frozen fibulae (17 for ORIF and 14 for MIPO) and 16 lyophilized tibiae (8 for ORIF and 8 for MIPO) were used as allografts, cut at a length of 6 to 8 cm and additionally shaped if their diameter could not fit in the medullary canal (Figure 1). Each graft was inserted through the lateral fracture line.
Figure 1.
Shaping of allograft's diameter.
Surgical technique for ORIF
A standard deltopectoral approach with a skin incision length of approximately 12–14 cm was used, starting at the tip of the coracoid process and running laterally toward the insertion of the deltoid muscle. Careful dissection was performed so that the periosteal blood supply was preserved as much as possible.
In cases with unstable fractures plus initial varus displacement and insufficient medial cortex, the allograft was positioned intramedullary and distally to the humeral head. Then it was medialized to the calcar region and elevated cranially, propping up the subchondral bone of the humeral head (Figures 2 and 3) so that the head was elevated from its varus position and aligned with the medial metaphyseal part of the bone. In these cases, the final graft position was vertical (Figure 4). In cases with unstable valgus-impacted PHFs, the graft was initially positioned in the medullary canal with its proximal part in contact with the subchondral bone of the humeral head and then pushed medially, acting as medial support and a repositioning tool for indirect reduction. In these cases, the graft was usually in vertical or sometimes in oblique position (Figure 5).
Figure 2.
Insertion of IMG and temporary fixation with K-wires. IMG: intramedullary graft; K-wires: Kirschner wires.
Figure 3.
Reposition of the humeral head relative to the allograft height and the medial cortex.
Figure 4.
3D-CT reconstruction of unstable PHF with initial varus displacement (a); intraoperative X-rays of the same fracture after LP fixation with IMG in vertical position (b). 3D: three-dimensional; CT: computed tomography; PHF: proximal humerus fracture; LP: locking plate; IMG: intramedullary graft.
Figure 5.
X-rays of a valgus-impacted PHF (a); intraoperative X-rays after MIPO showing an oblique IMG position (b). PHF: proximal humerus fracture; MIPO: minimally invasive plate osteosynthesis; IMG: intramedullary graft.
Surgical technique for MIPO
For the proximal window of the MIPO approach, a skin incision was made, starting from the anterolateral or lateral border of the acromion and extending 4–5 cm distally. For the distal window, an incision was made, starting 7 cm distal to the tip of the acromion after creation of a subdeltoid extraperiosteal tunnel by a blunt dissection. The axillary nerve was protected with the index finger during preparation of the submuscular tunnel and insertion of the plate.
Тhe principles of graft insertion are similar to those described for ORIF. The technique for indirect reduction of valgus-displaced PHFs is particularly useful when performing MIPO. Also, when MIPO technique is applied for varus-displaced PHFs and indirect reduction is mandatory, the IMG secures a strong cortical lever arm for the instrument used to elevate the head (e.g., blunt periosteal elevator).
At least 1 plate screw should pass through the graft, regardless of which one of the two techniques is applied.
Functional outcome assessment
Functional outcomes were assessed at the final follow-up using Disabilities of the Arm, Shoulder and Hand Score (DASH) and Absolute Constant–Murley Score (CSabs) with its derivatives—Relative Constant–Murley Score (CSrel) calculated by using reference values of the respective age and gender group described by Constant and Murley, and Individual Relative Constant–Murley Score (CSindiv), calculated as the percentage of the CSabs with regard to the contralateral shoulder of the patient. 37
Radiological evaluation
Preoperative radiographs of the shoulder in anteroposterior and Y-lateral views were obtained for all patients. For 24 of them, computed tomography (CT) was additionally performed.
Radiological evaluation considered the change of (a) neck-shaft angle (NSA) and (b) humeral head height (HHH), both registered between the intraoperative and final follow-up X-rays, and measured according to Agudelo et al. and Gardner et al., respectively.38,39 A decrease of more than 10° for NSA and/or more than 5 mm for HHH were considered as criteria for loss of fracture reduction.38,39 Evaluation of the local bone quality was performed by using the deltoid tuberosity index (DTI) described by Spross et al. 40 DTI ≥ 1.4 or < 1.4 was considered as corresponding to normal or low bone mineral density (BMD) of the proximal humerus, respectively. The most reliable Hertel's criteria to predict AVN of the humeral head 14 were used, namely (a) postero-medial metaphyseal extension of less than 8 mm, (b) disruption of the medal hinge —related to medial or lateral displacement of the shaft of more than 2 mm with respect to the humeral head—, and (c) anatomical neck fracture. Quality of fracture reduction was categorized as anatomical, acceptable, and malreduced, assessed according to the Schnetzke criteria. 15
Statistical analysis
Statistical analysis was conducted using Statistica 13.3.0 software package (StatSoft Inc, Tulsa, OK, USA). Descriptive analysis was performed to calculate frequency distributions, mean values, standard deviations (SDs), and 95% confidence intervals for each separate fixation technique. Independent-Samples t-test and Fischer's Exact Test were run to detect significant differences between the fixation techniques. Level of significance was set at 0.05 for all statistical tests.
Results
In total, 114 patients were surgically treated with simultaneous locked plating and intramedullary grafting (from January 2015 to November 2020). Sixteen patients passed away due to reasons unrelated to surgery. Three patients did not meet the inclusion criteria. Contact was established with 76 of the remaining 95 patients. Twenty-nine of them did not comply with the necessary visits in the hospital for a follow-up evaluation, mostly because of their advanced age and health concerns due to the coronavirus disease 2019 pandemic. As a result, 47 patients were retrospectively evaluated and appeared for final follow-up of a minimum of 12 months post-surgery. The majority of them were female (79%). Patients’ age was 60.5 ± 13.7 years (mean value ± SD, range 33–81 years) for ORIF and 66.3 ± 11.7 years (range 34–84 years) for MIPO. The follow-up period among all patients was 28 ± 17.2 months (range 12–79 months), with 27.4 ± 16.2 months (range 12–79 months) for ORIF and 29.6 ± 17.6 months (range 12–72 months) for MIPO. Patient, fracture, and surgical technique characteristics for ORIF and MIPO are detailed in Table 1.
Table 1.
Categories, parameters, surgical techniques, and p-values from statistical comparisons.
| Categories | Parameters | ORIF | MIPO | p-value |
|---|---|---|---|---|
| Patient characteristics | ||||
| Number of patients | 25 | 22 | – | |
| Follow-up duration (months) | 27.4 ± 16.2 | 29.6 ± 17.6 | 0.657 | |
| Age at surgery (years) | 60.5 ± 13.7 | 66.3 ± 11.7 | 0.128 | |
| Female patients | 18 (72%) | 19 (86%) | 0.297 | |
| Patients < 65 years | 13 (52%) | 9 (41%) | 0.561 | |
| Patients ≥ 65 years | 12 (48%) | 13 (59%) | 0.561 | |
| Mechanism of injury | ||||
| Falling from a standing height | 13 (52%) | 16 (73%) | 0.386 | |
| Falling from high altitude | 4 (16%) | 3 (14%) | 1.000 | |
| Road traffic accidents | 3 (12%) | 0 (0%) | 0.236 | |
| Other patients | 5 (20%) | 3 (14%) | 0.705 | |
| DTI | ||||
| DTI < 1.4 | 14 (56%) | 15 (68%) | 0.548 | |
| DTI ≥ 1.4 | 11 (44%) | 7 (32%) | 0.548 | |
| Fracture characteristics | Neer classification | |||
| 2-part fracture | 1 (4%) | 1 (5%) | 1.000 | |
| 3-part fracture | 6 (24%) | 8 (36%) | 0.327 | |
| 4-part fracture | 14 (56%) | 11 (50%) | 0.773 | |
| 2-part fracture with dislocation | 1 (4%) | 0 (0%) | 1.000 | |
| 3-part fracture with dislocation | 1 (4%) | 1 (5%) | 1.000 | |
| 4-part fracture with dislocation | 2 (8%) | 1 (5%) | 1.000 | |
| Calcar status | ||||
| Comminuted | 20 (80%) | 16 (73%) | 0.732 | |
| Noncomminuted | 5 (20%) | 6 (27%) | 0.732 | |
| Initial varus displacement | 14 (56%) | 13 (59%) | 1.000 | |
| Hertel's criteria | ||||
| Calcar segment < 8 mm | 18 (72%) | 11 (50%) | 0.144 | |
| Medial hinge disruption | 21 (84%) | 21 (95%) | 0.352 | |
| Anatomic neck fracture | 20 (80%) | 16 (73%) | 0.732 | |
| Surgical technique | Allograft | |||
| Fresh-frozen fibula | 17 (68%) | 14 (64%) | 0.768 | |
| Lyophilized tibia | 8 (32%) | 8 (36%) | 0.768 | |
| Quality of fracture reduction | ||||
| Anatomical | 12 (48%) | 3 (14%) | 0.014 | |
| Acceptable | 8 (32%) | 10 (45%) | 0.382 | |
| Malreduction | 5 (20%) | 9 (41%) | 0.200 | |
ORIF: open reduction and internal fixation; MIPO: minimally invasive plate osteosynthesis; DTI: deltoid tuberosity index.
Functional outcomes
The functional outcomes were satisfactory in terms of CSabs with 57.3 ± 21.2 points for ORIF and 52.4 ± 18.9 points for MIPO, good in terms of CSrel with 73.0 ± 24.1 points for ORIF and 73.9 ± 23.4 points for MIPO, and good in terms of CSindiv with 69.6 ± 24.8 points for ORIF and 64.0 ± 25.5 points for MIPO. There were no significant differences between ORIF and MIPO in terms of CSabs, CSrel, and CSindiv, p ≥ 0.409. DASH was 14.8 ± 12.5 points for ORIF and 18.7 ± 14.5 points for MIPO, with no significant difference between them, p = 0.324.
Radiological outcomes
With an intraoperative NSA of 136.4 ± 13.3° and an NSA of 128.6 ± 13.1° at the final follow-up , its decrease for ORIF was 7.8 ± 9.4°. For MIPO, with an intraoperative NSA of 126.7 ± 15.9° and an NSA of 118.5 ± 20.2° at the final follow-up, its decrease was 8.2 ± 15.6°. The decrease of HHH was 0.6 ± 5.5 mm for ORIF—with an intraoperative HHH of 13.5 ± 3.3 mm and an HHH of 12.9 ± 4.1 mm at the final-follow up. For MIPO, the decrease of HHH was 1.4 ± 2.6 mm—with an intraoperative HHH of 14.7 ± 4.9 mm and an HHH of 13.3 ± 5.8 mm at the final-follow up. No significant differences were detected between ORIF and MIPOb in terms of decrease of both NSA and HHH, p ≥ 0.380.
Significant difference between ORIF and MIPO was detected for the duration of the surgical procedure—84.7 ± 38.1 min for MIPO versus 165.8 ± 77.6 min for ORIF, p < 0.001.
The main clinical outcomes and complications for ORIF and MIPO are summarized in Table 2.
Table 2.
Categories, outcome measures, surgical techniques, and p-values from statistical comparisons.
| Categories | Outcome measures | ORIF | MIPO | p-value |
|---|---|---|---|---|
| Functional outcomes | CSabs | 57.3 ± 21.2 | 52.4 ± 18.9 | 0.409 |
| CSrel | 73.0 ± 24.1 | 73.9 ± 23.4 | 0.897 | |
| CSindiv | 69.6 ± 24.8 | 64.0 ± 25.5 | 0.428 | |
| DASH | 14.8 ± 12.5 | 18.7 ± 14.5 | 0.324 | |
| ROM | ||||
| Forward elevation (affected, °) | 124.1 ± 39.1 | 112.5 ± 42.8 | 0.336 | |
| Forward elevation (contralateral, °) | 163.7 ± 12.3 | 165.6 ± 15.1 | 0.637 | |
| Lateral elevation (affected, °) | 116.7 ± 40.7 | 109 ± 39 | 0.512 | |
| Lateral elevation (contralateral, °) | 161.9 ± 13.1 | 163.8 ± 14.7 | 0.641 | |
| External rotation (affected, °) | 59.4 ± 28.1 | 49.2 ± 28.5 | 0.223 | |
| External rotation (contralateral, °) | 85.7 ± 7.1 | 78.6 ± 20.2 | 0.106 | |
| Internal rotation (affected) | T12 (lateral thigh – T7) | T12 (lateral thigh – T7) | ||
| Internal rotation (contralateral) | T7 (lateral thigh – T7) | T7 (lateral thigh – T7) | ||
| Radiological outcomes | Intraoperative NSA (°) | 136.4 ± 13.3 | 126.7 ± 15.9 | 0.028 |
| Final follow-up NSA (°) | 128.6 ± 13.1 | 118.5 ± 20.2 | 0.047 | |
| Decrease of NSA (°) | 7.8 ± 9.4 | 8.2 ± 15.6 | 0.922 | |
| Intraoperative HHH (mm) | 13.5 ± 3.3 | 14.7 ± 4.9 | 0.906 | |
| Final follow-up HHH (mm) | 12.9 ± 4.1 | 13.3 ± 5.8 | 0.812 | |
| Decrease of HHH (mm) | 0.6 ± 5.5 | 1.4 ± 2.6 | 0.380 | |
| Complications | AVN of humeral head | 5 (20%) | 8 (32%) | 0.327 |
| Resorption of GT | 7 (28%) | 1 (4%) | 0.051 | |
| Secondary varus of < 110° | 1 (4%) | 5 (20%) | 0.084 | |
| Secondary screw penetration | 7 (28%) | 7 (28%) | 1.000 | |
| SAIt | 2 (8%) | 3 (12%) | 0.653 | |
| Arthritic changes of glenohumeral joint | 3 (12%) | 1 (4%) | 0.611 | |
| Nonunion | 0 (0%) | 0 (0%) | – | |
| Superficial or deep infection | 0 (0%) | 0 (0%) | – | |
| Reoperations | Hardware removal | 1 (4%) | 4 (16%) | 0.084 |
| Arthroplasty | 0 (0%) | 1 (4%) |
ORIF: open reduction and internal fixation; MIPO: minimally invasive plate osteosynthesis; CSabs: Absolute Constant–Murley Score; CSrel: Relative Constant–Murley Score; CSindiv: Individual Relative Constant–Murley Score; DASH: Disabilities of the Arm, Shoulder and Hand Score; ROM: range of motion; NSA: neck-shaft angle; HHH: humeral head height; AVN: avascular necrosis; GT: greater tuberosity; SAI: subacromial impingement.
Complications
There were 25 complications in 16 patients after ORIF and 25 complications in 11 patients treated with MIPO. AVN of the humeral head indicated 5 ORIF (20.0%) and 8 MIPO (32.0%) complications. Secondary varus displacement with an NSA decrease of more than 10° revealed 10 ORIF (40.0%) and 7 MIPO (28.0%) complications. One of these ORIF and 5 of the MIPO complications were related to a final NSA of less than 110°. Secondary screw penetration through the humeral head characterized 7 ORIF (28.0%) and 7 MIPO (28.0%) complications, and resulted from secondary varus displacement in 1 of these MIPO and 2 of the ORIF patients, with AVN of the humeral head in 6 of the MIPO and 5 of the ORIF cases. No primary screw penetrations were observed for either technique. Subacromial impingement (SAI) was diagnosed in 2 ORIF (8.0%) and 3 MIPO (12.0%) cases. In 4 of these 5 cases it developed because of displacement and proximalization of the greater tuberosity (GT), and in 1 of the cases with ORIF the reason was secondary varus displacement. For ORIF and MIPO, arthritic changes of the glenohumeral joint due to AVN of the humeral head occurred in 3 and 1 of these cases, respectively. In 7 cases after ORIF and 1 case after MIPO, resorption of the GT was diagnosed.
No nonunions, superficial and deep infections, or axillary nerve damage were observed for either technique. Secondary surgical procedures were performed in 6 patients. Five of the procedures necessitated hardware removal due to AVN and secondary screw penetration—in 1 ORIF and 4 MIPO patients. One MIPO patient underwent arthroplasty after developing AVN and secondary screw penetration. No significant differences were found between the two techniques in terms of complications and reoperation rate.
Discussion
The main finding of the present study is that MIPO using LP supplemented with IMG is associated with a significantly shorter operative time compared to ORIF. However, the functional and radiological outcomes, and complication rates were comparable for both surgical techniques.
ORIF via the conventional deltopectoral approach is the most commonly applied fixation technique for treatment of unstable PHFs.7,38,41 The advantages of ORIF include excellent visibility of the anterior aspect of the proximal humerus, ease in applying the LP, valuable options for extension of the exposure distally and proximally, and reduced risk of neurovascular injuries.7,41 On the other hand, the disadvantages of ORIF are related to the inevitable soft tissue stripping, significant risk of AVN—due to damage to the ascending branch of the anterior circumflex artery—, and the limited exposure of the lateral aspect of the proximal humerus.41,42 The MIPO technique with the deltoid splitting approach requires less soft tissue stripping and has a lower risk of injury to the anterior circumflex humeral artery, resulting in a lower rate of AVN.41–43 In addition, MIPO provides direct access to the lateral aspect of the proximal humerus, however, the procedure could be technically challenging, especially in the medial part of the proximal humerus, as the fragments need to be reduced indirectly. 41 Another disadvantage of this technique is the possible risk of axillary nerve damage.7,41,43 Regardless of the used technique, the LP fixation of unstable PHFs is still associated with a high complication rate. 44
The use of IMG for augmentation of the LP fixation was introduced by Gardner et al. in order to decrease the number of complications. 17 Biomechanical studies conclude that IMG increases stiffness and failure load of the bone-implant constructs, and limits fracture displacements,18–22 while simultaneously allowing interfragmentary micro-movements. 18 This additional rather elastic stabilization meets Lill's criteria for setting of an ideal device for fixation of PHFs. 45 Overall, the available clinical studies demonstrate good or even excellent functional results with a small percentage of complications when using IMG with LP for treatment of unstable PHFs.23–26
The available literature reports show that when using LP plus IMG, most authors apply ORIF for fixation for unstable PHFs23–29,31–36 and only one author applies MIPO with the deltoid splitting approach in this regard. 30 To the best of our knowledge, the current study is the first one comparing ORIF and MIPO techniques in presence of LP fixation with IMG. In a prospective randomized controlled trial, Sohn et al. 41 compared the two fixation techniques using LP without IMG for treatment of unstable PHFs and found no significant differences between them in terms of functional and radiological outcomes, however, the MIPO technique was related to significantly shorter operation time than ORIF. Another prospective randomized study by Bhayana et al. 43 , comparing these 2 surgical techniques, came to a similar conclusion. The results of the present study further support these findings that are relevant in case of IMG augmentation too. Although the functional and radiological outcomes do not appear to differ significantly, a shorter surgery duration may be beneficial for patients who have serious comorbidities and/or multiple fractures due to trauma. 41 One disadvantage of the MIPO technique is believed to be the potential damage of the axillary nerve that invariably lies over the plate holes occupied with calcar screws. 43 However, LP fixation with IMG through MIPO has the additional benefit of providing robust cortical support through IMG by eliminating the need of calcar screws. 46 The expectation that fracture reduction with MIPO is technically demanding may be supported by our results, showing that anatomical reduction is more prevalent in case of ORIF. However, the latter did not seem to affect the final functional outcomes of both techniques in the current study.
The functional outcomes of the current investigation are comparable with previously reported data on LP fixation with IMG in terms of DASH,23–26,29,33 CSindiv and CSrel.23–26,29,31,32,36 scores. In addition, the change of HHH for both techniques is within the reported range from 0.30 to 2.14 mm24,26–28,31,32 being below the critical level of 5 mm. In the literature, the critical change of NSA varies between 5° and 10°28,30,47,48, and some authors report values between 2.60° and 3.25°28,30–32,34,36 which are superior to our findings. However, although the change of NSA reflects the loss of reduction, this is not the most accurate criterion for varus deformation, as some patients with a change of more than 10° still have NSA within the physiological range of 120–150°. We support the conclusion of Shnetzke et al. 15 that NSA between 110° and 120° still represents an acceptable varus deformation, while values below 110° are not acceptable.
The rate of AVN in previous investigations on PHFs fixed with LP plus IMG varies from 0% to 10.6%,17,23–29,31,32 which is less than the rates reported in the current study. Besides, the current secondary screw penetration through the humeral head was much higher when compared with previous reports (0–4%).17,24,28,31 Another complication, identified in this study and not reported in previous work focusing on PHFs treated with LP plus IMG, was SAI and GT resorption. We were not able to extract the reason for the latter. One possible reason might have been the potential injury of the anterior circumflex vessels due to the deltopectoral approach used in 7 out of the 8 patients. 42 Another potential reason might have been the allograft itself, as Miyamura et al. 49 pointed out that fibular cortical strut may interfere with the revascularization, resulting in tuberosity resorption. In all 8 patients with GT resorption, a fresh-frozen fibular allograft was used. The complication was diagnosed on the final follow-up X-rays, and the shoulder function was seriously altered in only 2 of the patients.
Although the current study showed higher complication rate compared with previous reports, there were no significant differences between ORIF and MIPO in terms of functional and radiological outcomes, and complications rate.
The present study has some limitations. First, it was limited by its retrospective design, which could have introduced selection bias and potential for confounding. Second, the sample size was relatively small and futher work on a bigger cohort is therefore required to confirm these results. Third, the number of surgeons performing the procedure could have been a source of potential bias, influencing the validity of the study. However, all surgeons were from the same department, they all had more than 10 years of experience in the management of PHFs prior to the beginning of this study, and the surgical technique did not involve a long learning curve. Fourth, the follow-up duration was also relatively short. The minimum follow-up period was 12 months that may not have been sufficient to identify all negative clinical aspects after osteosynthesis of PHFs. However, the actual mean duration of the follow-up in this study was 28 months that is similar to that reported in the literature.
Conclusions
Locked plating with intramedullary graft augmentation of unstable proximal humerus fractures demonstrates similar functional and radiological outcomes, and similar complication rates when comparing open reduction and internal fixation with minimally invasive plate osteosynthesis. However, minimally invasive plate osteosynthesis is related to significantly shorter surgical time versus open reduction and internal fixation.
Acknowledgments
The authors are grateful to their patients for the cooperation during the diagnostic and treatment process, especially during the time of pandemic.
Authors’ contributions: All authors contributed to the conception of this study. In addition: Lyubomir Rusimov, Asen Baltov, Dian Enchev, and Mihail Rashkov contributed to the study design; Lyubomir Rusimov and Mariya Hadzhinikolova performed the data collection; Lyubomir Rusimov, Boyko Gueorguiev, Krasimira Prodanova, Mariya Hadzhinikolova, and Vladimir Rusimov analyzed the data; Krasimira Prodanova run the statistical analysis. Lyubomir Rusimov wrote the first manuscript draft; Boyko Gueorguiev, Vladimir Rusimov, and Mihail Rashkov revised the manuscript. All authors discussed the results and contributed to the final manuscript version. All authors read and approved the final manuscript version.
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical approval: The study was conducted in accordance with the principles of the Declaration of Helsinki as well as national legal and regulatory requirements. It was retrospectively registered and approval was granted by the local Ethics Committee of University Multiprofile Hospital for Active Treatment and Emergency Medicine “N. I. Pirogov”, Sofia, Bulgaria (No. EC–01/26.01.2023).
Funding: The authors received no financial support for the research, authorship, and/or publication of this article.
Informed consent: Informed consent has been obtained from all participants in the study, including their agreement for publication of the results.
ORCID iDs: Dian Enchev https://orcid.org/0009-0002-5699-7770
Boyko Gueorguiev https://orcid.org/0000-0001-9795-115X
Mariya Hadzhinikolova https://orcid.org/0000-0001-8317-2083
Lyubomir Rusimov https://orcid.org/0009-0000-6868-497X
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