Medial Support Screws Research Articles

Clinical and radiographic results of locking plate with medial support screw in Proximal Humerus fracture – the more, the better?

BackgroundThe calcar of the proximal humerus is a fundamental structure for medial humeral column support. This study aimed to assess the outcome of osteosynthesis across cases of unstable proximal humerus fractures (PHFs) with medial calcar comminution, following treatment with a PHILOS locking plate and medial support screw (MSS).MethodsBetween January 2010 and December 2018, we retrospectively analyzed the outcomes of 121 cases of osteosynthesis for PHFs with medial column disruption. For the medial support, at least one oblique screw was inserted within 5 mm of the subchondral bone in the inferomedial quadrant of the humeral head. All patients were categorized into two groups: 26 patients in the single MSS group, and 95 in the multiple MSS group. Follow-up after at least an year involved clinical and radiographic outcome evaluations, and correspondingly measuring the Constant-Murley score, University of California, Los Angeles (UCLA) shoulder scale, pain visual analogue scale (VAS), major complications, neck-shaft angle (NSA), humeral head height (HHH), and the eventual time to bone union. Risk factors for the major complications were assessed by multivariate logistic regression analyses.ResultsThe cohort’s mean age was 64.4 ± 15.4 years, and the mean follow-up duration was 19.5 ± 7.6 months. At the final follow-up, between the single MSS and multiple MSS groups, no significant differences in the Constant-Murley score (p = 0.367), UCLA score (p = 0.558), VAS (p = 0.571), time to bone union (p = 0.621), NSA loss (p = 0.424), and HHH loss (p = 0.364) were observed. The incidence of complications (p = 0.446) based on the number of MSS were not significantly different. The initial insufficient reduction after surgery (of NSA < 125°) was found to be a significant risk factor for post-surgical complications.ConclusionsTo treat unstable PHFs, the use of at least one MSS along with a locking plate system is sufficient to achieve satisfactory outcomes. Successful operative treatment using a locking plate for PHF treatment is inherent in anatomical fracture reduction, coupled with medial column support.

Risk of Axillary Nerve Injury With Medial Support Screws in Intramedullary Nails: An Anatomical Study.

In recent years, intramedullary nails with medial support screws for proximal humeral fractures have become available. Although these devices have a potential risk of iatrogenic axillary nerve injury, no studies have investigated the anatomical relationship between the medial support screws in the modern intramedullary nail and the axillary nerve. This study aimed to clarify the anatomical relationship between the medial support screws in the intramedullary nail and the axillary nerve. In total, 29 cadaveric shoulders (mean age: 82.6 years old (range: 61-105); 15 males and 14 females) were included in this study. Shoulders within whole-body cadavers were used in all cases. A single proximal humeral nail with medial support screws (ARISTO Proximal Humeral Nail; MDM, Tokyo, Japan) was used. The distance of each medial support screw from the axillary nerve and its branches was measured. In two (6.90%) of 29 shoulders, the axillary nerves came into contact with the medial support screws. In the remaining 27 of 29 shoulders (93.1%), the nerves were located proximal to the medial support screws. Medial support screws in proximal humeral fracture nails had the potential to injure the axillary nerve and its branches.

Finite element analyses of three minimally invasive fixation techniques for treating Sanders type II intra-articular calcaneal fractures

Background and objectiveCalcaneal Sanders type II or III fractures are highly disabling with significant burden. Surgical treatment modalities include open reduction and internal fixation (ORIF) techniques and a variety of minimally invasive surgical (MIS) approaches. ORIF techniques are associated with complications and traditional MIS techniques need extensive intraoperative fluoroscopic procedures. The present study aims to investigate the effects of three different minimally invasive internal fixation (MIIF) techniques used to treat Sanders type II intra-articular calcaneal fractures using finite element analyses.MethodsA 64-row spiral computed tomography scan was used to observe the calcaneus of a healthy adult. The scanning data were imported into Mimics in a DICOM format. Using a new model of a Sanders type II-B intra-articular calcaneal fracture, three minimally invasive techniques were simulated. Technique A involved fixation using an isolated minimally invasive locking plate; Technique B used a minimally invasive locking plate with one medial support screw; and Technique C simulated a screw fixation technique using four 4.0-mm screws. After simulating a 640-N load on the subtalar facet, the maximum displacement and von Mises stress of fragments and implants were recorded to evaluate the biomechanical stability of different fixation techniques using finite element analyses.ResultsAfter stress loading, the maximum displacements of the fragments and implants were located at the sustentaculum tali and the tip of sustentaculum tali screw, respectively, in the three techniques; however, among the three techniques, Technique B had better results for displacement of both. The maximum von Mises stress on the fragments was < 56 Mpa, and stress on the implants using the three techniques was less than the yield strength, with Technique C having the least stress.ConclusionAll three techniques were successful in providing a stable fixation for Sanders type II intra-articular calcaneal fractures, while the minimally invasive calcaneal locking plate with medial support screw fixation approach exhibited greater stability, leading to improved enhancement for the facet fragment; however, screw fixation dispersed the stress more effectively than the other two techniques.

Shoulder &amp; Elbow

The August 2023 Shoulder &amp; Elbow Roundup360 looks at: Motor control or strengthening exercises for rotator cuff-related shoulder pain? A multi-arm randomized controlled trial; Does the choice of antibiotic prophylaxis influence reoperation rate in primary shoulder arthroplasty?; Common shoulder injuries in sport: grading the evidence; The use of medial support screw was associated with axillary nerve injury after plate fixation of proximal humeral fracture using a minimally invasive deltoid-splitting approach; MRI predicts outcomes of conservative treatment in patients with lateral epicondylitis; Association between surgeon volume and patient outcomes after elective shoulder arthroplasty; Arthroscopic decompression of calcific tendinitis without cuff repair; Functional outcome after nonoperative management of minimally displaced greater tuberosity fractures and predictors of poorer patient experience.

The use of medial support screw was associated with axillary nerve injury after plate fixation of proximal humeral fracture using minimal invasive deltoid-splitting approach

BackgroundThe purpose of this study was to evaluate the incidence and risk factors for axillary nerve injury after plate fixation of humeral fractures using minimal invasive deltoid-splitting approach. We hypothesized that the use of medial support screw (MSS) would be associated with the outcome of axillary nerve injury. MethodsThis study retrospectively evaluated consecutive 32 patients who underwent surgical treatments for proximal or midshaft humeral fractures. Of them, we included 26 patients who were examined by electromyography/nerve conduction (EMG/NCV) study at 3–4 weeks postoperatively. We excluded 6 patients because two of them were not compliant to EMG/NCV and the remaining two died due to unrelated medical illness. Outcome assessments included pain, functional scores, range of motion, and radiographic results. ResultsThere were 8 male and 18 female patients with mean age of 67 ± 15 years. Mean duration of follow-up period was 31 ± 11 months. The mean time to EMG/NCS after surgery was 3.5 ± 0.6 weeks. EMG/NCS examinations revealed incomplete axillary nerve injury in 8 patients (31%) without complete nerve injury. Active forward elevation at 3 months postoperatively was significantly lower in patients with axillary nerve injury than in those without it (99° ± 12 and 123° ± 37, respectively, p = 0.047), although final clinical outcomes were not different. At surgery, MSS was used in 17 patients (65%), and 8 of them were associated with nerve injury. The use of MSS was only correlated with the outcome of axillary nerve injury, because the axillary nerve injury developed only in MSS group (p = 0.047). The MMT grade 4 in abduction strength was more common in patients with axillary nerve injury than in those without (p = 0.037). ConclusionsAxillary nerve injury was a concern after plate fixation of proximal humeral fracture using minimal invasive deltoid-splitting approach. The use of medial support screw to improve the stability could increase a risk of axillary nerve injury when used with this approach.

Treatment of Pauwels type III femoral neck fracture with medial femoral neck support screw: a biomechanical and clinical study

A femoral neck fracture is currently one of the most common types of fracture in clinical practice. The incidence continues to increase due to traffic accidents, trauma, and osteoporosis. This research includes a biomechanical study and a clinical retrospective study. In the biomechanical studies, three groups’ effects (Control Group: 3CCS, DHS group, and study Group: 3CCS + mFNSS group) were compared by vertical compression tests, torsion tests, and fatigue tests. All the data were collected and analyzed. We subsequently performed a retrospective analysis of 131 patients with femoral neck fractures. The operative time, intraoperative blood loss, quality of postoperative fracture reduction, and follow-up observation of fracture healing, screw retreatment rates and fixation failure rates, as well as femoral head necrosis rates and hip function in two groups with 3CCS and 3CCS + mFNSS were compared. By the biomechanical study, we found that 3CCS + Mfnss group were biomechanically superior to 3CCS group and superior to the DHS group in terms of resistance to torsion. However, it was less effective than the DHS group in compressive strength and fatigue resistance. In terms of clinical application, 3CCS + mFNSS group was found to have lower screw retreatment rates and femoral head necrosis rates, and to have better fracture healing rates than group with 3CCS, indicating that medial support screws can effectively resist the vertical shear forces of fracture ends and promote the stability and healing of fracture ends, as well as to reduce the incidence of postoperative complications.

Biomechanical study of Proximal humeral fracture fixation: Locking plate with medial support screw vs. locking plate with intramedullary fibular graft

BackgroundThe purpose of this study was to evaluate the biomechanical properties of two different fixation constructs in varus collapse proximal humerus fracture, locking plate with medial support screw and locking plate with intramedullary fibular graft. MethodsWe used 8 pairs of undamaged fresh-frozen humen cadaveric humeri and fibula from patients ranging in age from 62 to 81 years. We simulated a proximal humerus fracture with medial comminution using wedge shaped osteotomy. One group was fixed with locking plate with medial support screws, the other group with locking plate with intramedullary fibular graft. Biomechanical test was carried out using servohydraulic material testing system. We measured displacement of specimens under cyclic load test, maximum failure load, initial stiffness, and mode of failure under increasing load test. FindingsUnder cyclic loading, the displacement of the specimen was significantly less in the locking plate with fibular strut graft group than in the locking plate with medial support screws group. (p = 0.012) Under increasing load test, the Locking plate with fibular strut graft group showed higher values in both maximum failure load and initial stiffness than the Locking plate with medial support screws group, and this was statistically significant. (p = 0.012, p = 0.001). InterpretationIn biomechanical study, the locking plate with fibular strut graft showed significantly better results in all of the maximum failure load, initial stiffness, and gap depletion compared to the locking plate with medial support screws. Level of evidenceLevel IV.

Role of inferomedial supporting screws for secondary varus deformity in non-osteoporotic proximal humerus fracture: A biomechanical study.

The purpose of this study was to evaluate the effect of a medial support screw through a proximal humerus fracture. For this purpose, we verified whether the biomechanics are different according to the position of the screw while using the same number of screws. In addition, we tried to verify whether the insertion of additional inferomedial screws would make a difference in stability. Twenty-four proximal humerus bones were included in the study. A two-part fracture was created and fixed using a locking plate. Cyclic loading and load-to-failure test were applied to three groups: group A (proximal 6 screws + calcar screws), group B (proximal 6 screws), and group C (proximal 4 screws + calcar screws). Interfragmentary gaps were measured following cyclic loading and compared. The failure was defined when the bone breakage or medial gap closing was observed during ultimate failure load applied. The load-to-failure, maximum displacement, stiffness, and yield load were recorded and compared. The interfragmentary gap was differently reduced by 0.29 ± 0.14mm, 0.73 ± 0.25mm, and 0.53 ± 0.09mm following 1000 cyclic loading for groups A, B, and C, respectively. The load-to-failure was 945.22 ± 101.02N, 941.40 ± 148.90N, and 940.58 ± 91.78N in groups A, B, and C, respectively. The stiffness of group A (214.76 ± 34.0N/mm) was superior when compared to that of group C (171.12 ± 23.0N/mm; p = 0.025). The maximum displacement prior to failure, yield load, showed no significant difference between comparative groups. Our study did not show any additional biomechanical effects with the use of inferomedial supporting screws in non-osteoporotic proximal humerus fracture, besides making the fracture-plate construct stiff. The role of the inferomedial supporting screw was also unclear. However, the groups that used increased screw fixation and inferomedial screw insertion seemed to be more resistant to cyclic loading.

Effects of medial support screws on locking plating of proximal humerus fractures in elderly patients: a retrospective study.

This study aimed to explore the effects of medial support screws (MSS) on the locking proximal humeral plate in elderly patients who suffered from proximal humeral fractures. From December 2016 to December 2018, eighty-five elderly patients who suffered from proximal humeral fracture and received standard plate or locking plate with or without MSS were selected. The patients were allocated into 3 groups: Standard plate group (n=23), Locking plate without MSS group (n=34) and Locking plate with MSS group (n=28). Clinical data from all these 3 groups were collected and analyzed. These eighty-five elder patients (ranging 60-78 years) accomplished a follow-up with an average of 16.3 months. The outcome data showed that significant difference was found on the Constant score, humeral internal rotation angle and humeral height ratio (all the P<0.05) among 3 groups, and a highest Constant score and a lowest humeral internal rotation angle and humeral height ratio loss was revealed in Locking platelet with MSS group. Furthermore, the lowest incidence of post-operation complication events (7.1%, P=0.051) and an evident reduction of secondary surgery incidence (P=0.021) was also presented in Locking plate with MSS among these 3 groups. The medial support screws in the locking proximal humeral plate in treating proximal humeral fractures could reduce humerus restoration loss and humeral internal rotation angle.

\u201c90/90\u201d Plating of proximal humerus fracture\u2014a technical note

IntroductionWhile locking plates have markedly improved fixation of proximal humerus fractures, a cohort of fractures remains difficult to treat. This cohort has been identified as fractures with marked medial comminution and varus deformity. Loss of reduction and fixation failure are the most frequently reported complications for this cohort. We report the use of an orthogonal 1/3 tubular plate to augment the proximal humerus locking plate.MethodsThe subject underwent osteosynthesis for a four-part proximal humerus fracture with medial comminution. Fixation was performed within 24 h of injury. Standard deltopectoral approach exposed the fracture. Sutures were sited to control the tuberosities and cuff. Initial reduction was held with a K-wire and augmented with a three-hole 1/3 tubular plate. Proximal humerus locking plate was sited in standard fashion including locked medial support screws. Reduction was confirmed both clinically and with intra-operative radiography.ResultsThe technique provided satisfactory results. At 6 months, the fracture had fully united with no loss of reduction. At 1 year, the patient had excellent range of motion.ConclusionThe use of a 1/3 tubular plate to augment fixation of proximal humerus fractures with medial comminution may provide a simple, reproducible, and cost-effective method to decrease loss of reduction and subsequent malunion.

Biomechanical evaluation of hybrid double plate osteosynthesis using a locking plate and an inverted third tubular plate for the treatment of proximal humeral fractures.

BackgroundTreating proximal humerus fractures can be challenging because of large metaphyseal defects that conceal anatomical landmarks. In such cases, medial cortical support with, for example, calcar screws, is mandatory. Nevertheless, varus dislocations and implant failures in patients with impaired bone quality persist. Thus, the need for effective treatment of these patients exists. Hybrid double plate osteosynthesis was introduced as an alternative, yielding similar results as calcar screws. However, a biomechanical comparison of the stability of these two techniques is pending.MethodsCadaveric humeral specimens were treated with plate osteosynthesis and calcar screws (group 1, n = 9) or hybrid double plate osteosynthesis (group 2, n = 9) using a proximal humerus fracture model with a two-part fracture. Displacement, stiffness, failure mode, and ultimate load were examined biomechanically in a cyclic compressive-loading scenario.ResultsAlthough the hybrid double plate osteosynthesis (group 2) tended to confer higher stiffnesses than the medial support screws at higher cycles (group 1), this trend was below the level of significance. The displacement revealed non-significantly lower values for group 1 as compared with group 2 for cycles 50 and 2000, but at 5000 cycles, group 2 offered non-significantly lower displacement values than group 1. The ultimate load tended to be non-significantly higher in the hybrid double plate osteosynthesis group (group 2: 1342±369 N, group 1: 855±408 N). Both groups yielded similar failure rates, with the majority of failures in group 2 being gap closures (n = 8), whereas those in group 1 being plate dislocations (n = 4).ConclusionsThe use of an additive plate osteosynthesis in the region of the bicipital groove may be a potential alternative to the previously-established method of using calcar screws. The biomechanical data obtained in this study suggests that hybrid double plate osteosynthesis is as rigid and robust as calcar screws.

Influence of Medial Support Screws on the Maintenance of Fracture Reduction after Locked Plating of Proximal Humerus Fractures.

Background:Technical aspects of the correct placement of medial support locking screws in the locking plate for proximal humerus fractures remain incompletely understood. This study was to evaluate the clinical relationship between the number of medial support screws and the maintenance of fracture reduction after locked plating of proximal humerus fractures.Methods:We retrospectively evaluated 181 patients who had been surgically treated for proximal humeral fractures (PHFs) with a locking plate between September 2007 and June 2013. All cases were then subdivided into one of four groups as follows: 75 patients in the medial cortical support (MCS) group, 26 patients in the medial multiscrew support (MMSS) group, 29 patients in the medial single screw support (MSSS) group, and 51 patients in the no medial support (NMS) group. Clinical and radiographic evaluations included the Constant-Murley score (CM), visual analogue scale (VAS), complications, and revision surgeries. The neck-shaft angle (NSA) was measured in a true anteroposterior radiograph immediately postoperation and at final follow-up. One-way analysis of variance or Kruskal-Wallis test was used for statistical analysis of measurement data, and Chi-square test or Fisher's exact test was used for categorical data.Results:The mean postoperative NSAs were 133.46° ± 6.01°, 132.39° ± 7.77°, 135.17° ± 10.15°, and 132.41° ± 7.16° in the MCS, MMSS, MSSS, and NMS groups, respectively, and no significant differences were found (F = 1.02, P = 0.387). In the final follow-up, the NSAs were 132.79° ± 6.02°, 130.19° ± 9.25°, 131.28° ± 12.85°, and 127.35° ± 8.50° in the MCS, MMSS, MSSS, and NMS groups, respectively (F = 4.40, P = 0.008). There were marked differences in the NSA at the final follow-up between the MCS and NMS groups (P = 0.004). The median (interquartile range [IQR]) NSA losses were 0.0° (0.0–1.0)°, 1.3° (0.0–3.1)°, 1.5° (1.0–5.2)°, and 4.0° (1.2–7.1)° in the MCS, MMSS, MSSS, and NMS groups, respectively (H = 60.66, P < 0.001). There were marked differences in NSA loss between the MCS and the other three groups (MCS vs. MMSS, Z = 3.16, P = 0.002; MCS vs. MSSS, Z = 4.78, P < 0.001; and MCS vs. NMS, Z = 7.34, P < 0.001). There was also significantly less NSA loss observed in the MMSS group compared to the NMS group (Z = −3.16, P = 0.002). However, there were no significant differences between the MMSS and MSSS groups (Z = −1.65, P = 0.225) or the MSSS and NMS groups (Z = −1.21, P = 0.099). The average CM scores were 81.35 ± 9.79, 78.04 ± 8.97, 72.76 ± 10.98, and 67.33 ± 12.31 points in the MCS, MMSS, MSSS, and NMS groups, respectively (F = 18.68, P < 0.001). The rates of excellent and good CM scores were 86.67%, 80.77%, 65.52%, and 43.14% in the MCS, MMSS, MSSS, and NMS groups, respectively (χ2= 29.25, P < 0.001). The median (IQR) VAS scores were 1 (0–2), 1 (0–2), 2 (1–3), and 3 (1–5) points in the MCS, MMSS, MSSS, and NMS groups, respectively (H = 27.80, P < 0.001). Functional recovery was markedly better and VAS values were lower in the MCS and MMSS groups (for CM scores: MCS vs. MSSS, P < 0.001; MCS vs. NMS, P < 0.001; MMSS vs. MSSS, P = 0.031; and MMSS vs. NMS, P < 0.001 and for VAS values: MCS vs. MSSS, Z = 3.31, P = 0.001; MCS vs. NMS, Z = 4.64, P < 0.001; MMSS vs. MSSS, Z = −2.09, P = 0.037; and MMSS vs. NMS, Z = −3.16, P = 0.003).Conclusions:Medial support screws might help enhance mechanical stability and maintain fracture reduction when used to treat PHFs with medial metaphyseal comminution or malreduction.

Screw augmentation reduces motion at the bone-implant interface: a biomechanical study of locking plate fixation of proximal humeral fractures

Shear forces at the bone-implant interface lead to a loss of reduction after locking plate fixation of proximal humeral fractures. The aim of the study was to analyze the roles of medial support screws and screw augmentation in failure loads and motion at the bone-implant interface after locking plate fixation of proximal humeral fractures. Unstable 3-part fractures were simulated in 6 pairs of cadaveric humeri and were fixed with a DiPhos-H locking plate (Lima Corporate, Udine, Italy). An additional medial support screw was implanted in 1 humerus of every donor. The opposite humerus was stabilized with a medial support screw and additional bone cement augmentation of the 2 anteriorly directed head screws. Specimens were loaded in the varus bending position. Stiffness, failure loads, plate bending, and the motion at the bone-implant interface were evaluated using an optical motion capture system. The mean load to failure was 669 N (standard deviation [SD], 117 N) after fixation with medial support screws alone and 706 N (SD, 153 N) after additional head screw augmentation (P = .646). The initial stiffness was 453 N/mm (SD, 4.16 N/mm) and 461 N/mm (SD, 64.3 N/mm), respectively (P = .594). Plate bending did not differ between the 2 groups. However, motion at the bone-implant interface was significantly reduced after head screw augmentation (P < .05). The addition of bone cement to augment anteriorly directed head screws does not increase stiffness and failure loads but reduces motion at the bone-implant interface. Thus, the risk of secondary dislocation of the head fragment may be reduced.

The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

BackgroundThe purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs) in the locking proximal humeral plate for treating proximal humerus fractures.MethodsThirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed.ResultsConstructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (P<0.0001). When the proximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P≤0.0207). Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture.ConclusionsAnatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

The effects of different reconstructions of medial column support on clinical outcomes after locked plating of proximal humerus fractures

Objective To investigate the effects of different reconstructions of the medial support on the clinical outcomes of locked plating of proximal humeral fractures.Methods Between June 2005 and June 2011,130 patients underwent locked plating of proximal humerus fracture and completed follow-ups in our department.They were 46 men and 84 women,18 to 88 years of age (average,56.1 years).By the Neer classification,56 cases were two-part fractures,52 three-part fractures and 22 four-part fractures.They were categorized into 4 groups according to the 4 different reconstructions of medial support of the proximal humerus.In the CS (cortical support) group,60 patients had the reconstruction by anatomic reduction of the cortical bone; in the MS (multi-screw support) group,12 patients had the reconstruction by insertion of more than 2 medial support screws; in the SS (single-screw support) group,17 patients had the reconstruction by insertion of only one medial support screw; in the NS group,41 patients had no reconstruction of medial support of the proximal humerus.The postoperative Constant scores of the shoulder function,visual analog scale (VAS) pain scores,loss of the head-shaft angle,complications and reoperation rates were compared among the 4 groups.Results The follow-ups for the patients ranged from 12 to 42 months (mean,18.8 months).At the last follow-up,the CS,MS,SS and NS groups had a mean Constant score of 81.2 ± 12.7,75.5±9.7,69.4±12.1 and 67.5±11.6,respectively; a mean VAS score of 1.4±1.9,1.7±1.6,2.5 ± 2.2 and 3.2 ± 2.4,respectively; a mean loss of the head-shaft angle of 0.8° ± 1.0°,1.4° ± 2.3°,3.4° ± 6.8° and 4.4° ± 4.0°,respectively.With respect to the 3 indexes,there were no significant differences between the CS and MS groups (P ＞ 0.05),there were significant differences between the CS group and respectively the SS and NS groups (P ＜ 0.05),and there were also significant differences between the MS and NS groups (P ＜ 0.05).However,there were no significant differences between any 2 of the 4 groups regarding postoperative complications or the reoperation rate.Conclusions Anatomic reduction with the medial cortical contact is preferable in reconstruction of medial support in locked plating of proximal humerus fractures.However,medial support with multiple medial support screws may help enhance the mechanical stability of the bone-implant construct,especially in cases of medial comminution,bone defects or malreduction of the medial cortical bone. Key words: Shoulder joint; Humeral fractures; Fracture fixation, internal; Bone plates

The effect of medial support screw in locking plate fixation of proximal humeral fractures

Objective To evaluate the influence of medial support screw in locking plate fixation of proximal humeral fractures. Methods From June 2006 to November 2009, 68 cases of proximal humeral fractures were treated with locking plate fixation. The patients were divided into two groups, - MSS group and + MSS group. 39 patients were assigned to - MSS group and treated only with locking plates. 29 patients were assigned to + MSS group and treated with a medial support screw in addition to the locking plate. Statistical methods were applied to assess postoperative radiological parameters and shoulder function of both groups.Results The mean follow-up period was 7.4 months (range, 3 to 12 months). All fractures united at an average of 5.6 months. Fixation failure was observed in 1 case of the + MSS group and in 9 cases of the - MSS group,which were all found within 12 weeks postoperatively. The incidence of fixation failure was significantly different between the two groups( P = 0.036), so was the greater loss of neck-shaft angle observed in - MSS group ( P = 0.049). No difference was found between the two groups on the incidence of varus displacement of the humeral head(P=0.216). According to Constant Shoulder Score, the excellent and good rate was 79% and 62% in + MSS group and -MSS group, respectively. The difference in Constant Shoulder Score was statistically significant. Conclusion Locking plate fixation has been shown to lead to satisfactory outcomes for the treatment of proximal humeral fractures. An additional medial support screw, which can be inserted into the medial inferior region of the humeral head, is suggested to maintain reduction of the fracture and to improve stability of the fixation. Key words: Humeral fractures,proximal; Internal fixators; Treatment outcome; Locking plate

The clinical benefit of medial support screws in locking plating of proximal humerus fractures: a prospective randomized study

The purpose of this study was to evaluate the clinical benefit of medial support screws for locking plating of proximal humerus fractures. Seventy-two consecutive patients underwent prospective treatment for proximal humerus fractures with locking plates between October 2007 and September 2008. Sixty-eight patients accomplished a mean 30.8-month follow-up and were randomized into two groups: 39 patients were treated with only a locking plate and were classified in the -MSS (medial support screw) group, and 29 patients were included in the + MSS group, which were fixed with additional medial support screws. Clinical and radiological investigations were performed in both groups. The fractures united at an average of 13.6 weeks after final surgery. Comparably better shoulder function recovery was achieved in the +MSS group with regard to the Constant shoulder score (P = 0.01), with the respective excellent and good rates of 79% and 62%. Eleven patients developed various complications. A statistical difference (P = 0.036) was observed regarding the failure rate (23.1% in the -MSS group vs. 3.4% in the +MSS group). The early loss of fixation was related to higher age (P < 0.001) and less initial neck-shaft angle (NSA) (P = 0.011) of the patients. However, bone mineral density was not significantly associated with loss of fixation (P = 0.076). Although no difference was found in all types of the fractures between the +MSS and -MSS groups regarding immediate postoperative NSA, we observed a significantly lower final NSA in the -MSS group and greater secondary angle loss in the subgroup of Neer three-part (P = 0.033 and 0.015, respectively) and four-part fractures (P = 0.043 and 0.027). Anatomical reduction can substantially decrease the risk of postoperative failure in locking plating of proximal humerus fractures. Medial support for proximal humerus fractures seems to have no benefits in Neer two-part fractures. However, the additional medial support screws inserted into the medio-inferior region of the humeral head may help to enhance mechanical stability in complex fractures and allow for better maintenance of reduction.