Nael Hawi

Intraoperative measurement of femoral antetorsion using the anterior cortical angle method: a novel use for smartphones.

Malrotation after femoral nailing is a common problem, yet estimation of the correct rotation during nailing remains a technical challenge. In the current study, a novel technique was developed for determining femoral antetorsion, the anterior cortical angle (ACA) method. The ACA is the angle between a line along the anterior aspect of the femoral neck and the posterior condylar line of the distal femur. The principal advantage of this method is that it facilitates intra‐operative assessment of femoral antetorsion by utilizing the positional technology integrated in smartphones. This measurement is directly comparable to measurements made using computed tomography (CT) scans. The objective of the current study was to investigate the possibility and to validate the feasibility and accuracy of the new method and compare the results obtained with the traditional methods of antetorsion estimation via CT and surgical navigation technology.

Factors influencing neck anteversion during femoral nailing: A retrospective analysis of 220 torsion-difference CTs

BACKGROUND Rotational malalignment is a well-known complication following intramedullary nailing of femoral shaft fractures. The hypothesis of this study is that various modifiable factors, such as position on the surgical table or nailing technique, influence the incidence of torsional abnormalities. METHODS For this retrospective study, we analysed the data of 220 consecutive patients with femoral shaft fractures and postoperative torsion-difference computed tomographies (CTs), performed from 2001 to 2009 in our institution. Mean age of the patients was 33±15 years. Average delay to surgery was 8±11 days. The average postoperative neck anteversion difference between both sides was 11±8°. A p value <0.05 was considered to be statistically significant. RESULTS The average postoperative neck anteversion difference between both sides was not significantly affected from the position of the patient on the surgical table (supine or lateral, p=0.698), the delay till surgery (p=0.989), the nailing technique (antegrade or retrograde, p=0.793; reamed or unreamed, p=0.930), the type of the implant (p=0.885) and the experience of the surgeon (p=0.055). Furthermore, the learning curve regarding this complication was long and not predictable. CONCLUSIONS We could not identify any risk factors that are associated with an increased incidence of torsional deformities, and thus our hypothesis could not be confirmed. The inability to identify such risk factors renders the prevention of this complication particularly problematic. The invention of new techniques for better intra-operative control of the torsion is probably the only solution to further reduce the incidence of postoperative malrotational deformities.

Range of motion assessment of the shoulder and elbow joints using a motion sensing input device: a pilot study.

BACKGROUND Motion sensing input devices could provide a practical and low-cost alternative method for repeated range of motion measurements. This study aimed to assess the reliability, accuracy and time requirements of a motion sensing input device (Microsoft Kinect) for ROM measurements comparing it with goniometer based measurements and subjective estimation. MATERIAL AND METHODS Full ROM was measured in 14 shoulder and elbow joints using the different methods. The order was randomly selected and each movement was measured twice. The results were recorded in degrees and the time measured in seconds. RESULTS In general, there was a poor to moderate agreement between the Kinect system compared to the goniometer. There was a good agreement between the goniometer-based and the subjective technique. The Kinect-based technique showed excellent test-retest reliability. CONCLUSION The Kinect system showed good test-retest reliability, but lower accuracy compared to goniometer-based measurements. Improvements in patient positioning and measurement protocol standardization must be made before its implementation in clinical practice.

The Anatomic Basis for the Arthroscopic Latarjet Procedure A Cadaveric Study

Background: The Latarjet technique is a reliable treatment option for recurrent anterior shoulder instability. However, the complication rate has been reported to be as high as 30%, with 1.6% of patients suffering a nerve injury. The all-arthroscopic Latarjet procedure has been gaining popularity, even as it has introduced its own challenges. Given that the surgeon is not able to palpate the nerves, their localization and protection can be difficult. Additionally, the use of different instruments can lead to distinct nerve injury mechanisms. Purpose: To describe the anatomic trajectory of the musculocutaneous, axillary, and suprascapular nerves in relation to the arthroscopic Latarjet approach. Using this information, guidance is provided for reducing nerve injuries during instrumentation and screw insertion. Study Design: Descriptive laboratory study. Methods: A total of 50 cadaveric shoulders from 25 whole-body specimens were examined. The specimens were placed in the beach-chair position, and the deltopectoral and dorsal approaches were used to expose the relevant structures. A subscapularis muscle split was performed between the inferior and middle thirds of the tendon. Digital caliper measurements were taken between various points of the trajectories of the nerves and surrounding anatomic landmarks. The location of the nerves relative to the split was recorded. Results: The musculocutaneous nerve lay within the split in 66% of the shoulders (n = 33); it was medial to the split in 28% (n = 14); it was found lateral to split in 2% (n = 1); and it was not identified in 4% of shoulders (n = 2). The mean length of the axillary nerve was 4.0 cm (95% CI, 3.7-4.2) from the exit of the plexus to the quadrangular space. The axillary nerve was found to be within the split in 50% of the shoulders (n = 25) and medial to the split in the remaining 50% (n = 25). The suprascapular nerve at the level of the supraspinatous fossa passed 3.3 cm (95% CI, 3.1-3.5) medial to the superior rim of the posterior glenoid. The nerve curves around the root of the spine at the spinoglenoid notch level, approximating the glenoid rim to a distance of 2.1 cm (95% CI, 2.0-2.2). Finally, the nerve runs medially again before branching out into smaller fibers to innervate the infraspinatus muscle at a distance of 2.9 cm (95% CI, 2.7-3.1) from the inferior glenoid rim. Based on these findings, there is an approximately 2 cm–wide safe zone from the edge of the glenoid rim for the insertion of graft-fixing screws. Conclusion: When performing a subscapularis split in the arthroscopic Latarjet procedure, the risk of injuries to the musculocutaneous and axillary nerves could be reduced by aiming the switching stick inserted through the posterior portal toward the lateral edge of the intended location of the split. Injuries to the suprascapular nerve could be prevented by aiming the graft-fixing screws laterally toward the edge of the glenoid rim. Clinical Relevance: This study clarifies the location of the nerves relevant to the arthroscopic Latarjet technique and provides anatomic information that could help the surgeon reduce the risk of injuries to the musculocutaneous, axillary, and suprascapular nerves.

Septic single-stage knee arthrodesis after failed total knee arthroplasty using a cemented coupled nail

Knee arthrodesis is a potential salvage procedure for limb preservation after failure of total knee arthroplasty (TKA) due to infection. In this study, we evaluated the outcome of single-stage knee arthrodesis using an intramedullary cemented coupled nail without bone-on-bone fusion after failed and infected TKA with extensor mechanism deficiency. Between 2002 and 2012, 27 patients (ten female, 17 male; mean age 68.8 years; 52 to 87) were treated with septic single-stage exchange. Mean follow-up duration was 67.1months (24 to 143, n = 27) (minimum follow-up 24 months) and for patients with a minimum follow-up of five years 104.9 (65 to 143,; n = 13). A subjective patient evaluation (Short Form (SF)-36) was obtained, in addition to the Visual Analogue Scale (VAS). The mean VAS score was 1.44 (SD 1.48). At final follow-up, four patients had recurrent infections after arthrodesis (14.8%). Of these, three patients were treated with a one-stage arthrodesis nail exchange; one of the three patients had an aseptic loosening with a third single-stage exchange, and one patient underwent knee amputation for uncontrolled sepsis at 108 months. All patients, including the amputee, indicated that they would choose arthrodesis again. Data indicate that a single-stage knee arthrodesis offers an acceptable salvage procedure after failed and infected TKA.

Radiological outcome and intraoperative evaluation of a computer-navigation system for femoral nailing: A retrospective cohort study

AIM Intraoperative determinations of femoral antetorsion and leg length during fixation of femoral shaft fractures present a challenge. In femoral shaft fracture fixations, a computer-navigation system has shown promise in determining antetorsion and leg length discrepancies. This retrospective cohort study aimed to determine whether the use of computer navigation during femoral nailing procedures reduced postoperative femoral malrotation and leg length discrepancy, as well as the number of revision cases. We also sought to determine whether radiation exposure time was reduced when computer navigation was used. MATERIALS AND METHODS Of 246 patients treated for femoral shaft fractures between 2004 and 2012, we selected those that received postoperative computed tomography for rotation and leg length control. We included 24 patients who received navigation-assisted treatments and 48 who received unassisted treatments, matched for age, sex, and fracture type. All patients were treated by femoral nailing. RESULTS The groups showed significant differences in the mean (standard deviation (SD) delay before surgery (navigation-assisted vs. unassisted groups: 8.5 ± 3.2 vs. 5.2 ± 5.8 days; P<0.05) and surgery times (163.7 ± 43.94 vs. 98.3 ± 28.13 min; P<0.001). The groups were significantly different in the mean (SD) radiation exposure time (4.43 ± 1.35 vs. 3.73 ± 1.5 min; P=0.042), and were not significantly different in the postoperative femoral antetorsion difference (8.83 ± 5.52° vs. 12.4 ± 9.2°; P=0.056), or in the postoperative length discrepancy (0.92 ± 0.75 vs. 0.95 ± 0.94 cm; P=0.453). Four (16.7%) navigation-assisted and 15 (31.25%) unassisted surgeries got revision for torsion and/or length corrections. CONCLUSION Our results showed that, compared to unassisted femoral surgery, the computer-navigation system did not improve postoperative results or reduce radiation exposure. In the future, improvements in handling and application could facilitate the workflow and may provide better postoperative results. Currently, computer navigation may provide advantages for complicated or sophisticated cases, such as complex three-dimensional deformity corrections. LEVEL OF EVIDENCE Level III.

Effect of medial opening wedge high tibial osteotomy on intraarticular knee and ankle contact pressures

High tibial osteotomy (HTO) is a commonly used surgical technique for treating moderate osteoarthritis (OA) of the medial compartment of the knee by shifting the center of force towards the lateral compartment. Previous studies have documented the effects of HTO on the biomechanics of the knee. However, the effects of the procedure on the contact pressures within the ankle joint have not been as well described. Seven cadavers underwent an HTO procedure with sequential 5° valgus realignment of the leg up to 15° of correction. An axial force of up to 550 N was applied and the intraarticular pressure was recorded. Minor valgus realignment of the proximal tibia does not significantly alter the biomechanics of the ankle. However, moderate‐to‐large changes in proximal tibial alignment result in significantly decreased tibiotalar contact surface area and in changes in intraarticular ankle pressures. These findings are clinically relevant, as they provide a biomechanical rationale for the diagnosis and treatment of ankle symptoms in the setting of lower limb malalignment or after alignment correction procedures.

3D navigated implantation of the glenoid component in reversed shoulder arthroplasty. Feasibility and results in an anatomic study.

Reversed shoulder arthroplasty is an alternative to total shoulder arthroplasty for various indications. The long‐term results depend on stable bone fixation, and correct positioning of the glenoid component. The potential contribution of image guidance for reversed shoulder arthroplasty procedures was tested in vitro.

Progress towards intra-operative measurement of femoral antetorsion

Rotational malalignment following intramedullary nailing is a well-recognised problem. The threshold for clinically relevant malrotation has been established to be in the region of 15° whereas the incidence of significant malrotation following femoral nailing ranges from 22 to 43 percent. Many studies have been performed to address this issue with the major challenge acknowledged to be intraoperative control of femoral anteversion. In the current study, the investigators developed and analysed a novel method to estimate the femoral antetorsion based on computed tomography (CT) data. They hypothesized that this method would be intra-operatively feasible and repeatable without further radiation. CT scans (n=166) of femoral neck fractures performed between 2005 and 2010 were evaluated. Twenty patients had a femoral neck fracture and thus were excluded. Every femoral neck was measured according the method described by Jend et al. and the current authors. In contrast to the Jend method, the current authors described femoral antetorsion as the angle between the ventral cortex of the femoral neck and the posterior condylar line. To determine this angle, the axial cuts from computed tomography data were studied. In order to maximise measurement consistencty among cases, the axial cut which displayed the intertrochanteric crest was selected. Mean femoral antetorsion is 12.15°±10.04° according to Jend et al. In comparison, a mean angle of 12.61°±11.16° was demonstrated in the current study. The absolute difference in measuring the femoral neck angle when these different methods are compared was 4.44°. Statistically, there is no significant difference between the mean results for femoral antetorsion. The advantage of the method proposed in the current study, is the opportunity to enter the ventral femoral cortex during the surgical procedure without disturbing the process of femoral nailing. Thus, the surgeon can avail of continuous control of femoral rotation intra-operatively.

Intraoperative imaging of the shoulder: A comparison of two- and three-dimensional imaging techniques

BACKGROUND Isocentric three-dimensional C-arms allow for more effective intraoperative fracture reduction control compared to two-dimensional imaging techniques. However, this design is not appropriate for shoulder scanning. OBJECTIVE To assess the feasibility of using a newer generation variable isocentric flat detector 3D C-arm for intraoperative glenohumeral and acromioclavicular joint assessment and to compare the accuracy of its intraoperative 3D imaging technology to a standard two-dimensional (2D) flat detector fluoroscope. METHODS Five whole-body human cadavers were used (ten shoulders). Native shoulder scans were obtained. A glenohumeral arthrotomy was performed and several injuries and procedures were simulated. Five independent orthopaedic surgeons reviewed each scan and filled out a questionnaire assessing the quality of the images using a visual analog scale (VAS) and a points scoring system. RESULTS The examiners rated the 3D images as very-good-to-excellent according to the established parameters: image quality; visualization of the corticalis and the spongiosa; delineation of the joint surface; presence of artifacts; and clinical assessment capability. This high quality of the images led to a higher interobserver reliability for 3D images compared to 2D images. CONCLUSIONS Variable isocentric 3D C-arm technology is feasible for intraoperative assessment of shoulder procedures. Assessment of 3D images in shoulder procedures showed better interexaminer reliability in this experiment compared to 2D images. With the aid of intraoperative 3D shoulder imaging, intraoperative 3D C-arm navigation could help improve accuracy in the clinical setting.