Introduction. A new triggered electromyography test for detection of stimulus diffusion to intercostal muscles of the contralateral side during thoracic pedicle screw placement was evaluated. Experimental research was carried out in order to determine if, using this test, neural contact at different aspects of the spinal cord and nerve roots could be discriminated. Methods. Nine industrial pigs (60–75 kg) had 108 pedicle screws placed bilaterally in the thoracic spine (T8–T13). Neural structures were stimulated under direct vision at different anatomic locations from T9 to T12. Recording electrodes were placed over the right and left intercostal muscles. Increasing intensity of the stimulus was applied until muscle response was detected at the contralateral side (diffusion phenomenon). After this first experiment, the thoracic spine was instrumented. Screws were placed in the pedicle in two different positions, the anatomic intrapedicular location and with purposeful contact with the neural elements. Results. Response thresholds to direct stimulation of nerve root at different points were significantly lower than those obtained by stimulation of the dorsal aspect of the spinal cord (0.44±0.22 mA vs 1.38±0.71 mA). However, a 24-fold stimulation intensity (6.50±0.29 mA) was necessary to obtain diffusion of the EMG response to the opposite left side if the right nerve root was stimulated. Only a 2-fold increment (3.17±0.93 mA) was able to elicit diffusion of EMG responses to the contralateral side when stimulation was applied to the dorsal aspect of the spinal cord. Contralateral EMG responses after high increases of stimulation thresholds indicated nerve root contact. Diffusion phenomenon after low threshold increments reflected medullar contact. Electromyography recordings after triggered stimulation of the screws showed that only screws in contact with the spinal cord had significantly lower responses (2.72±1.48 mA). Conclusion. Stimulus-triggered EMG could only discriminate screws with violation of the medial pedicle wall if they were contact with neural tissues. Recording EMG-potentials at the contralateral paraspinal muscles (stimulus diffusion phenomenon) proved to be a reliable method to discriminate which of the neural structures was at risk

Aims. Proximal femur fractures treatment can involve anterograde nailing with a single or double cephalic screw. An undesirable failure for this fixation is screw cut-out. In a single-screw nail, a tip-apex distance (TAD) greater than 25 mm has been associated with an increased risk of cut-out. The aim of the study was to examine the role of TAD as a risk factor in a cephalic double-screw nail. Methods. A retrospective study was conducted on 112 patients treated for intertrochanteric femur fracture with a double proximal screw nail (Endovis BA2; EBA2) from January to September 2021. The analyzed variables were age, sex, BMI, comorbidities, fracture type, side, time of surgery, quality of reduction, pre-existing therapy with bisphosphonate for osteoporosis, screw placement in two different views, and TAD. The last follow-up was at 12 months. Logistic regression was used to study the potential factors of screw cut-out, and receiver operating characteristic curve to identify the threshold value. Results. A total of 98 of the 112 patients met the inclusion criteria. Overall, 65 patients were female (66.3%), the mean age was 83.23 years (SD 7.07), and the mean follow-up was 378 days (SD 36). Cut-out was observed in five patients (5.10%). The variables identified by univariate analysis with p < 0.05 were included in the multivariate logistic regression model were screw placement and TAD. The TAD was significant with an odds ratio (OR) 5.03 (p = 0.012) as the screw placement with an OR 4.35 (p = 0.043) in the anteroposterior view, and OR 10.61 (p = 0.037) in the lateral view. The TAD threshold value identified was 29.50 mm. Conclusion. Our study confirmed the risk factors for cut-out in the double-screw nail are comparable to those in the single screw. We found a TAD value of 29.50 mm to be associated with a risk of cut-out in double-screw nails, when good fracture reduction is granted. This value is higher than the one reported with single-screw nails. Therefore, we suggest the role of TAD should be reconsidered in well-reduced fractures treated with double-screw intramedullary nail. Cite this article: Bone Jt Open 2024;5(6):457–463

Aims. Several previously identified patient-, injury-, and treatment-related factors are associated with the development of nonunion in distal femur fractures. However, the predictive value of these factors is not well defined. We aimed to assess the predictive ability of previously identified risk factors in the development of nonunion leading to secondary surgery in distal femur fractures. Methods. We conducted a retrospective cohort study of adult patients with traumatic distal femur fracture treated with lateral locking plate between 2009 and 2018. The patients who underwent secondary surgery due to fracture healing problem or plate failure were considered having nonunion. Background knowledge of risk factors of distal femur fracture nonunion based on previous literature was used to form an initial set of variables. A logistic regression model was used with previously identified patient- and injury-related variables (age, sex, BMI, diabetes, smoking, periprosthetic fracture, open fracture, trauma energy, fracture zone length, fracture comminution, medial side comminution) in the first analysis and with treatment-related variables (different surgeon-controlled factors, e.g. plate length, screw placement, and proximal fixation) in the second analysis to predict the nonunion leading to secondary surgery in distal femur fractures. Results. We were able to include 299 fractures in 291 patients. Altogether, 31/299 fractures (10%) developed nonunion. In the first analysis, pseudo-R. 2. was 0.27 and area under the receiver operating characteristic curve (AUC) was 0.81. BMI was the most important variable in the prediction. In the second analysis, pseudo-R. 2. was 0.06 and AUC was 0.67. Plate length was the most important variable in the prediction. Conclusion. The model including patient- and injury-related factors had moderate fit and predictive ability in the prediction of distal femur fracture nonunion leading to secondary surgery. BMI was the most important variable in prediction of nonunion. Surgeon-controlled factors had a minor role in prediction of nonunion. Cite this article: Bone Jt Open 2023;4(8):584–593

Introduction. Biomechanical studies have shown that a long, centrally placed screw is favourable in scaphoid fracture fixation. A volar percutaneous transtrapezial approach was developed to facilitate central screw placement. The purpose of this study was to evaluate radiographic changes at the ST-joint at long term follow up in patients where this approach was used. Method. Results were graded with use of the visual analogue scale (VAS) and modified Mayo wrist score. Radiographs of both hands, comprising an anteroposterior, lateral and 45 degrees pronated oblique view were obtained. Degenerative changes at the ST-joint were staged according to the modified Eaton & Glickel classification. Results. 34 patients with an average age of 34 years were followed at a mean of 6.1 years (4–9). Union was obtained in all at an average time of 6.4 weeks (6–10). There were no significant differences in VAS score and ROM, between the operated and nonoperated side (p>0.05). The mean Mayo wrist score was 93 (80–100). Three patients showed stage 2 osteoarthritis of the ST-joint. In 2 patients, stage 2 osteoarthritis was found in both the injured and uninjured side. One patient had asymptomatic stage 2 osteoarthritic changes at the injured side. Discussion. The advantages of the volar percutaneous transtrapezial approach include central screw placement, without the need for manipulation of the wrist. From the present study it can be concluded that the volar percutaneous transtrapezial approach to fix scaphoid fractures does not lead to significant radiographic degenerative changes in the ST joint at a follow-up of more than 6 years

Controversy surrounds the management of displaced three- and four-part fractures of the proximal humerus. The percutaneous Resch technique of stabilisation involves minimal soft-tissue dissection and a reduced risk of stiffness and avascular necrosis. However, it requires a second operation to remove Kirschner wires and the humeral block. We describe a modification of this technique that dispenses with the need for this second operation and relies on a sequential pattern of screw placement. We report the outcome of 32 three- or four-part fractures of the proximal humerus treated in this way at a mean follow-up of 3.8 years (2 to 8)). There were 14 men and 18 women with a mean age of 56 years (28 to 83). At final follow-up the mean Oxford shoulder scores were 38 (31 to 44) and 39 (31 to 42), and the mean Constant scores were 79 (65 to 92) and 72 (70 to 80) for three- and four-part fractures, respectively. We further analysed the results in patients aged < 60 years with high-energy fractures and those aged ≥ 60 years with osteoporotic fractures. There were no cases of nonunion or avascular necrosis. The results were good and comparable to those previously reported for the Resch technique and other means of fixation for proximal humeral fractures. We would recommend this modification of the technique for the treatment of displaced three-part and four-part fractures in patients both younger and older than 60 years of age

A new anterior intrapelvic approach for the surgical management of displaced acetabular fractures involving predominantly the anterior column and the quadrilateral plate is described. In order to establish five ‘windows’ for instrumentation, the extraperitoneal space is entered along the lateral border of the rectus abdominis muscle. This is the so-called ‘Pararectus’ approach. The feasibility of safe dissection and optimal instrumentation of the pelvis was assessed in five cadavers (ten hemipelves) before implementation in a series of 20 patients with a mean age of 59 years (17 to 90), of whom 17 were male. The clinical evaluation was undertaken between December 2009 and December 2010. The quality of reduction was assessed with post-operative CT scans and the occurrence of intra-operative complications was noted. In cadavers, sufficient extraperitoneal access and safe instrumentation of the pelvis were accomplished. In the patients, there was a statistically significant improvement in the reduction of the fracture (pre- versus post-operative: mean step-off 3.3 mm (. sd. 2.6) vs 0.1 mm (. sd. 0.3), p < 0.001; and mean gap 11.5 mm (. sd. 6.5) vs 0.8 mm (. sd. 1.3), p < 0.001). Lesions to the peritoneum were noted in two patients and minor vascular damage was noted in a further two patients. Multi-directional screw placement and various plate configurations were feasible in cadavers without significant retraction of soft tissues. In the treatment of acetabular fractures predominantly involving the anterior column and the quadrilateral plate, the Pararectus approach allowed anatomical restoration with minimal morbidity related to the surgical access

Aims

Proper preoperative planning benefits fracture reduction, fixation, and stability in tibial plateau fracture surgery. We developed and clinically implemented a novel workflow for 3D surgical planning including patient-specific drilling guides in tibial plateau fracture surgery.

Background. Locking internal fixation through a relatively small surgical dissection presents an innovative technique for managing distal tibial extra-articular fractures. The aim of this study is to evaluate the biomechanical properties of one locking internal fixation plate used to treat these injuries. Method. An AO/OTA43-A3 fracture was created in synthetic composite tibiae. Locking internal fixation was achieved with an anatomically pre-contoured medial distal tibial locking plate. Comparisons were made between different screw configurations in holes proximal to the fracture and monocortical versus bicortical fixation. Axial stiffness was measured using a universal materials testing machine. Finite element analysis (FEA) was used to model the elastic deformation of the constructs. Outcome measures were axial stiffness under physiological loading conditions and compression load to failure. Results. A trend towards reduced mean axial stiffness from the bicortical to the monocortical fixation constructs was observed. The physical model demonstrated no difference in measured mean axial stiffness between constructs with all screw holes filled and constructs with 2 screws in the holes closest and furthest from the fracture site. There was a 19% reduction in mean measured axial stiffness between constructs with all holes filled and in constructs with 2 screws in adjacent holes furthest from the fracture site (p<0.05). FEA predicted increased plate deflection and reduced construct axial stiffness with increasing distance of screw placement from the osteotomy site. Conclusion. Axial stiffness of distal tibial extra-articular metaphyseal fractures stabilized by locking internal fixation is dependent upon the configuration of the screw in the plate

Background. Controversy persists regarding preference between Herbert and Acutrak screw for internal fixation of scaphoid non-union. Acutrak screw has been shown to have better biomechanical compression properties than Herbert screw in the laboratory setting. The aim of this study was to assess the clinical, radiological and functional outcome of patients treated with the two different screw systems. Methods. A retrospective review of the results of patients with scaphoid non-union treated by a single surgeon. Group 1 comprised of 61 patients treated with Herbert screw between July1996 and June2000 and Group 2 comprised of 71 patients treated with Acutrak screw between July 2000 and December 2005. Union rates were assessed radiologically and clinically. Functional outcome was measured by using modified Mayo wrist score. Results. Both groups of patients were comparable in terms of age (25.3:27.3yrs, Herbert: Acutrak) and their occupations in relation to wrist loading. The mean time interval between injury and surgery was 12.2months for Herbert group (range: 3–144months) and 17months (range: 4–180months) in Acutrak group. Time to union was similar for both groups. Union rate was 93% (66) in Acutrak compared to 77% (47) in Herbert screw. Union rate was related to fracture site (Herbert p=0.01; Acutrak p=0.0001) and higher when the screw had been placed axially (Herbert; p=0.006, Acutrak; p=0.004) in the scaphoid. Ninety seven percent of screws had been placed axially in Acutrak compared to 84% in the Herbert. Functional outcome was satisfactory in 85% of Acutrak group compared to 67% in Herbert. Wrist fusion was performed in 4 patients in Herbert group due to progressive wrist pain and in 1 patient in Acutrak group due to similar reason. Conclusion. Acutrak screw provides more accurate method of screw placement and a higher union rate when compared to Herbert screw

Aims

We compared the accuracy, operating time and radiation exposure of the introduction of iliosacral screws using O-arm/Stealth Navigation and standard fluoroscopy.

Aims

Fractures of the distal femur can be challenging to manage and are on the increase in the elderly osteoporotic population. Management with casting or bracing can unacceptably limit a patient’s ability to bear weight, but historically, operative fixation has been associated with a high rate of re-operation. In this study, we describe the outcomes of fixation using modern implants within a strategy of early return to function.

Aims

The aims of this study were to determine the cumulative ten-year survivorship of hips treated for acetabular fractures using surgical hip dislocation and to identify factors predictive of an unfavourable outcome.

The aim of this study was to determine the comorbid risk factors for failure in young patients who undergo fixation of a displaced fracture of the femoral neck. We identified from a prospective database all such patients ≤ 60 years of age treated with reduction and internal fixation. The main outcome measures were union, failure of fixation, nonunion and the development of avascular necrosis.

There were 122 patients in the study. Union occurred in 83 patients (68%) at a mean follow-up of 58 months (18 to 155). Complications occurred in 39 patients (32%) at a mean of 11 months (0.5 to 39). The rate of nonunion was 7.4% (n = 9) and of avascular necrosis was 11.5% (n = 14). Failures were more common in patients over 40 years of age (p = 0.03). Univariate analysis identified that delay in time to fixation (> 24 hours), alcohol excess and pre-existing renal, liver or respiratory disease were all predictive of failure (all p < 0.05). Of these, alcohol excess, renal disease and respiratory disease were most predictive of failure on multivariate analysis.

Younger patients with fractures of the femoral neck should be carefully evaluated for comorbidities that increase the risk of failure after reduction and fixation. In patients with a history of alcohol abuse, renal or respiratory disease, arthroplasty should be considered as an alternative treatment.

Coronal plane fractures of the posterior femoral condyle, also known as Hoffa fractures, are rare. Lateral fractures are three times more common than medial fractures, although the reason for this is not clear. The exact mechanism of injury is likely to be a vertical shear force on the posterior femoral condyle with varying degrees of knee flexion. These fractures are commonly associated with high-energy trauma and are a diagnostic and surgical challenge. Hoffa fractures are often associated with inter- or supracondylar distal femoral fractures and CT scans are useful in delineating the coronal shear component, which can easily be missed. There are few recommendations in the literature regarding the surgical approach and methods of fixation that may be used for this injury. Non-operative treatment has been associated with poor outcomes. The goals of treatment are anatomical reduction of the articular surface with rigid, stable fixation to allow early mobilisation in order to restore function. A surgical approach that allows access to the posterior aspect of the femoral condyle is described and the use of postero-anterior lag screws with or without an additional buttress plate for fixation of these difficult fractures.

Cite this article: Bone Joint J 2013;95-B:1165–71.

We created virtual three-dimensional reconstruction models from computed tomography scans obtained from patients with acetabular fractures. Virtual cylindrical implants were placed intraosseously in the anterior column, the posterior column and across the dome of the acetabulum. The maximum diameter which was entirely contained within the bone was determined for each position of the screw. In the same model, the cross-sectional diameters of the columns were measured and compared to the maximum diameter of the corresponding virtual implant.

We found that the mean maximum diameter of virtual implant accommodated by the anterior columns was 6.4 mm and that the smallest diameter of the columns was larger than the maximum diameter of the equivalent virtual implant.

This study suggests that the size of the screw used for percutaneous fixation of acetabular fractures should not be based solely on the measurement of cross-sectional diameter and that virtual three-dimensional reconstructions might be useful in pre-operative planning.

We identified 11 women with a mean age of 74 years (65 to 81) who sustained comminuted distal radial and ulnar fractures and were treated by volar plating and slight shortening of the radius combined with a primary Sauvé-Kapandji procedure.

At a mean of 46 months (16 to 58), union of distal radial fractures and arthrodesis of the distal radioulnar joint was seen in all patients. The mean shortening of the radius was 12 mm (5 to 18) compared to the contralateral side. Flexion and extension of the wrist was a mean of 54° and 50°, respectively, and the mean pronation and supination of the forearm was 82° and 86°, respectively. The final mean disabilities of the arm, shoulder and hand score was 26 points. According to the Green and O’Brien rating system, eight patients had an excellent, two a good and one a fair result.

The good clinical and radiological results, and the minor complications without the need for further operations related to late ulnar-sided wrist pain, justify this procedure in the elderly patient.

We investigated the stability of seven Schatzker type II fractures of the lateral tibial plateau treated by subchondral screws and a buttress plate followed by immediate partial weight-bearing. In order to assess the stability of the fracture, weight-bearing inducible displacements of the fracture fragments and their migration over a one-year period were measured by differentially loaded radiostereometric analysis and standard radiostereometric analysis, respectively. The mean inducible craniocaudal fracture fragment displacements measured −0.30 mm (−0.73 to 0.02) at two weeks and 0.00 mm (−0.12 to 0.15) at 52 weeks. All inducible displacements were elastic in nature under all loads at each examination during follow-up. At one year, the mean craniocaudal migration of the fracture fragments was −0.34 mm (−1.64 to 1.51).

Using radiostereometric methods, this case series has shown that in the Schatzker type II fractures investigated, internal fixation with subchondral screws and a buttress plate provided adequate stability to allow immediate post-operative partial weight-bearing, without harmful consequences.

Percutaneous stabilisation of tibial fractures by locking plates has become an accepted form of osteosynthesis. A potential disadvantage of this technique is the risk of damage to the neurovascular bundles in the anterior and peroneal compartments. Our aim in this anatomical study was to examine the relationship of the deep peroneal nerve to a percutaneously-inserted Less Invasive Stabilisation System tibial plate in the lower limbs of 18 cadavers. Screws were inserted through stab incisions. The neurovascular bundle was dissected to reveal its relationship to the plate and screws.

In all cases, the deep peroneal nerve was in direct contact with the plate between the 11th and the 13th holes. In ten specimens the nerve crossed superficial to the plate, in six it was interposed between the plate and the bone and in the remaining two specimens it coursed at the edge of the plate.

Percutaneous insertion of plates with more than ten holes is not recommended because of the risk of injury to the neurovascular structures. When longer plates are required we suggest distal exposure so that the neurovascular bundle may be displayed and protected.

The purpose of this study was to compare the clinical and radiological outcome of patients with intact, broken and removed syndesmosis screws after Weber B or C ankle fracture with an associated injury to the syndesmosis. We hypothesised that there would be no difference. Of a possible 142 patients who fulfilled our inclusion criteria, 52 returned for clinical and radiological assessment at least one year after surgery. Of these, 27 had intact syndesmosis screws, ten had broken screws, and 15 had undergone elective removal of the screw. The mean American Orthopaedic Foot and Ankle Society ankle/hindfoot score was 83.07 (sd 13.59) in the intact screw group, 92.40 (sd 12.69) in the broken screw group, and 85.80 (sd 11.33) in the removed screw group (p = 0.0466).

There was no difference in clinical outcome of patients with intact or removed syndesmotic screws. Paradoxically, patients with a broken syndesmosis screw had the best clinical outcome. Our data do not support the removal of intact or broken syndesmosis screws, and we caution against attributing post-operative ankle pain to breakage of the syndesmosis screw.

We describe our early operative experience with a new pelvic reduction frame and the standard of reduction of fractures of the pelvic ring which we achieved in the first 35 consecutive patients, with 34 acute fractures and one nonunion. The pre-operative and immediate post-operative radiographs were measured, using two methods, to find the maximum radiological displacement of the fracture and the quality of the reduction according to the criteria of Tornetta and Matta.

There were 19 vertical shear fractures and 16 compression injuries. The mean age of the patients was 33.5 years (10 to 59) and mean delay to surgery was 4.6 days (0 to 16) in the 34 acute injuries. The mean operative time in isolated procedures was 103.4 minutes (sd 6.5). All but one patient had iliosacral screws implanted, 18 had screws in the anterior column, six had plates at the symphysis pubis and 12 had anterior external fixators. The mean maximum horizontal or vertical displacement was improved from 30.8 mm (sd 2.7) to a mean of 7.1 mm (sd 0.7). The reduction was assessed as excellent in ten patients, good in 18, and fair in the remainder. There was no significant influence on the quality of the reduction caused by obesity (p = 0.34), the type of fracture (p = 0.41) or delay to surgery (p = 0.83).

The frame was shown to be effective, allowing the surgeon to obtain a satisfactory reduction and fixation of acute displaced disruptions of the pelvic ring.