Segond’s fracture: a biomechanical cadaveric study using navigation

Background

Segond’s fracture is a well-recognised radiological sign of an anterior cruciate ligament (ACL) tear. While previous studies evaluated the role of the anterolateral ligament (ALL) and complex injuries on rotational stability of the knee, there are no studies on the biomechanical effect of Segond’s fracture in an ACL deficient knee. The aim of this study was to evaluate the effect of a Segond’s fracture on knee rotation stability as evaluated by a navigation system in an ACL deficient knee.

Materials and methods

Three different conditions were tested on seven knee specimens: intact knee, ACL deficient knee and ACL deficient knee with Segond’s fracture. Static and dynamic measurements of anterior tibial translation (ATT) and axial tibial rotation (ATR) were recorded by the navigation system (2.2 OrthoPilot ACL navigation system B. Braun Aesculap, Tuttlingen, Germany).

Results

Static measurements at 30° showed that the mean ATT at 30° of knee flexion was 5.1 ± 2.7 mm in the ACL intact condition, 14.3 ± 3.1 mm after ACL cut (P = 0.005), and 15.2 ± 3.6 mm after Segond’s fracture (P = 0.08). The mean ATR at 30° of knee flexion was 20.7° ± 4.8° in the ACL intact condition, 26.9° ± 4.1° in the ACL deficient knee (P > 0.05) and 30.9° ± 3.8° after Segond’s fracture (P = 0.005). Dynamic measurements during the pivot-shift showed that the mean ATT was 7.2 ± 2.7 mm in the intact knee, 9.1 ± 3.3 mm in the ACL deficient knee(P = 0.04) and 9.7 ± 4.3 mm in the ACL deficient knee with Segond’s fracture (P = 0.07). The mean ATR was 9.6° ± 1.8° in the intact knee, 12.3° ± 2.3° in the ACL deficient knee (P > 0.05) and 19.1° ± 3.1° in the ACL deficient knee with Segond’s lesion (P = 0.016).

Conclusion

An isolated lesion of the ACL only affects ATT during static and dynamic measurements, while the addition of Segond’s fracture has a significant effect on ATR in both static and dynamic execution of the pivot-shift test, as evaluated with the aid of navigation.

     

Short uncemented stems allow greater femoral flexibility and may reduce peri-prosthetic fracture risk: a dry bone and cadaveric study

BackgroundShort femoral stems for uncemented total hip arthroplasty have been introduced as a safe alternative to traditional longer stem designs. However, there has been little biomechanical examination of the effects of stem length on complications of surgery. This study aims to examine the effect of femoral stem length on torsional resistance to peri-prosthetic fracture.ResultsSynthetic femora implanted with short stems fractured at a significantly higher torque (27.1 vs. 24.2 Nm, p = 0.03) and angle (30.3° vs. 22.3°, p = 0.002) than those implanted with long stems. Fracture patterns of the two groups were different, but showed remarkable consistency within each group. These characteristic fracture patterns were closely replicated in the pair of cadaveric femora.ConclusionsThis new short-stemmed press-fit femoral component allows more femoral flexibility and confers a higher resistance to peri-prosthetic fracture from torsional forces than long stems.     

Simultaneous bilateral shoulder and bilateral central acetabular fracture dislocation: What to do?

Musculoskeletal injuries following seizures have a high morbidity and mortality. These injuries are often missed and the diagnosis is delayed due to a lack of clinical suspicion and appropriate investigations. We report a case of 72 years old male with simultaneous bilateral central acetabular fracture dislocation and bilateral posterior shoulder fracture dislocation secondary to an epileptic seizure. Present study highlights the significance of clinical suspicion and clinico-radiological evaluation for diagnosis of a rare injury following episode of seizures. Simultaneous fracture dislocation of all four limbs treated with a holistic approach can lead to a good functional recovery. Surgical management with open reduction and internal fixation is preferred and replacement arthroplasty should be reserved for cases with implant failure and elderly patients.     

Severity of vertebral fracture and risk of hip fracture: a nested case�Ccontrol study

Summary  

Severe vertebral fractures strongly predicted subsequent hip fracture in this population-based study. Such high-risk patients should be provided with clinical evaluation and care for osteoporosis.     

Rheumatoid arthritis and incident fracture in women: a case–control study

Background

To examine fracture incidence in women with rheumatoid arthritis (RA) for an entire geographical region of south-eastern Australia.

Methods

Women aged 35 years and older, resident in the Barwon Statistical Division (BSD) and clinically diagnosed with RA 1994–2001 were eligible for inclusion as cases (n?=?1,008). The control population (n?=?172,422) comprised the entire female BSD population aged 35 years and older, excluding those individuals identified as cases. Incident fractures were extracted from the prospective Geelong Osteoporosis Study Fracture Grid. We calculated rate ratios (RR) and 95% confidence intervals (CI) to compare the age-adjusted rate of fracture between the RA and non-RA populations, and used a chi-square test to compare proportions of fractures between women with and without RA, and a two-sided Mann–Whitney U-test to examine age-differences.

Results

Among 1,008 women with RA, 19 (1.9%) sustained a fracture, compared to 1,981 fractures sustained by the 172,422 women without RA (1.2%). Fracture rates showed a trend for being greater among women diagnosed with RA (age-adjusted RR 1.43, 95%CI 0.98-2.09, p?=?0.08). Women with RA sustained vertebral fractures at twice the expected frequency, whereas hip fractures were underrepresented in the RA population (p?<?0.001). RA status was not associated with the likelihood of sustaining a fracture at sites adjacent to joints most commonly affected by RA (p?=?0.22).

Conclusion

Given that women with RA have a greater risk of fracture compared to women without RA, these patients may be a suitable target population for anti-resorptive agents; however, larger studies are warranted.     

Location and classification of popliteus tendon’s origin: cadaveric study

Background  

In posterolateral insufficiency, many investigators have proposed a lateral tunnel for PT reconstruction. Although they were usually located at the anterior and proximal to the lateral femoral epicondyle, there are still controversies regarding the exact location of PT tunnel. The aim of the present study was to describe our novel findings of femoral attachment of popliteus tendon (PT) and lateral collateral ligament (LCL) and to present an adequate femoral tunnel site, based on the cadaver dissection.     

Freehand technique for C2 pedicle and pars screw placement: is it safe?

Background Context

During placement of C2 pedicle and pars screws, intraoperative fluoroscopy is used so that neurovascular complications can be avoided, and screws can be placed in the proper position. However, this method is time consuming and increases radiation exposure. Furthermore, it does not guarantee a completely safe and accurate screw placement.

Transpedicular screw fixation for type II Hangman’s fracture: a motion preserving procedure

Opinions have varied regarding the optimal treatment of an unstable Hangman’s fracture. C2 pedicle screw instrumentation is a biomechanically strong fixation which although done through a simple posterior approach, is a technically demanding procedure. This prospective, non-randomized multicentre study included 15 consecutive patients with displaced type II traumatic spondylolisthesis of the axis. There were nine males and six females with a mean age of 37 years at surgery. The cause of injury was a road traffic accident in 11 patients and a fall from height in 4 patients. All patients had a single stage reduction and direct transpedicular screw fixation through the C2 pedicles. During follow-up, clinical evaluation and plain X-rays were performed at each visit; at 6-month follow-up, additional dynamic lateral flexion/extension views and a CT scan were performed. The average follow-up period was 32 months (range 25–56 months). At final follow-up, all patients were asymptomatic and regained a good functional outcome with no limitation of range of motion; all the patients showed solid union with no implant failure. There were no neurological complications. At 6-month follow-up, CT evaluation showed fusion in all patients and an adequate position of 28 screws. Two pedicle screws (6.6%) showed minimal (defined as <2 mm) intrusion; one into the spinal canal and the other into the vertebral foreamen. Transpedicular screw fixation through the C2 pedicles is a safe and effective method in treating type II traumatic spondylolisthesis of the axis resulting in good clinical and radiological outcomes. Adequate reduction was achieved and motion segments were preserved with its use.     

Hakuba’s triangle: a cadaveric study detailing its anatomy and neurovascular contents with vascular and skull base implications

Neurosurgical Review - Hakuba’s triangle is a superior cavernous sinus triangle that allows for wide and relatively safe exposure of vascular and neoplastic lesions. This study provides...     

Percutaneous pedicle screw placement under single dimensional fluoroscopy with a designed pedicle finder—a technical note and case series

Background Context

Minimally invasive spine surgery has become increasingly popular in clinical practice, and it offers patients the potential benefits of reduced blood loss, wound pain, and infection risk, and it also diminishes the loss of working time and length of hospital stay. However, surgeons require more intraoperative fluoroscopy and ionizing radiation exposure during minimally invasive spine surgery for localization, especially for guidance in instrumentation placement. In addition, computer navigation is not accessible in some facility-limited institutions.

How are adjacent spinal levels affected by vertebral fracture and by vertebroplasty? A biomechanical study on cadaveric spines

Background Context

Spinal injuries and surgery may have important effects on neighboring spinal levels, but previous investigations of adjacent-level biomechanics have produced conflicting results. We use “stress profilometry” and noncontact strain measurements to investigate thoroughly this long-standing problem.

Kendrick's extrication device and unstable pelvic fractures: Should a trochanteric belt be added? A cadaveric study

IntroductionPre-hospital pelvic stabilisation is advised to prevent exsanguination in patients with unstable pelvic fractures (UPFs). Kendrick's extrication device (KED) is commonly used to extricate patients from cars or crevasses. However the KED has not been tested for potential adverse effects in patients with pelvic fractures. The aim of this study was to examine the effect of the KED on pubic symphysis diastasis (SyD) with and without the use of a trochanteric belt (TB) during the extraction process following a MVC.Materials and methodsLeft-sided “open-book” UPFs were created in 18 human cadavers that were placed in seven different positions simulating pre-extraction and extraction positions using the KED with and without a TB in two different positions (through and over the thigh straps). The SyD was measured using anteroposterior radiographs. The effects of the KED with and without TB, on the SyD, were evaluated.ResultsThe KED alone resulted in a non-significant increase of the SyD compared to baseline, whereas the addition of a TB to the KED resulted in a significant reduction of the SyD (p < 0.001). The TB through the straps provided a significantly better reduction than the TB over the straps in the extracted position (p < 0.05).ConclusionOur study demonstrated that a TB in combination with the KED on UPFs is an effective way to achieve early reduction. The addition of the TB in combination with the KED could be considered for Pre-Hospital Trauma Life Support (PHTLS) training protocols.     

Is the fracture morphology in the sagittal plane important in determining the ideal placement of the lag screw in intertrochanteric femoral fractures?: Ideal lag screw placement in intertrochanteric fractures in the sagittal plane

ObjectiveThe aim of this study was to determine the ideal placement of the lag screw taking into account the fracture morphology in the sagittal plane.Materials and methodsThree different morphology of fractures were created on the sagittal plane in femur models obtained in 3D CT scanning: posteriorly angled (Type A), transverse (Type B) and anteriorly angled (Type C). The lag screw was applied in each of the three fracture morphology as neutral, anteverted and retroverted in the sagittal plane. The nine models created were transferred to the Ansys Workbench program and analyzes were performed.ResultsIn Type A fracture, the stress value at the lag screw apex increase as the lag screw placement changes from the anteverted position to the retroverted position. It decreases in the Type B and Type C fractures. As the lag screw placement is changed towards the anteverted position, the stress at the lag screw-nail junction decreases in the Type A fracture and increases in the Type C fracture . There is no significant change in the Type B fracture. As the lag screw placement is changed towards the anteverted position, the stress in the calcar region increases in Type A fractures and decreases in Type C fractures. There is no significant change in type B fractures.ConclusionWhile the ideal lag screw placement in a type A fracture in the sagittal plane is the retroverted placement, the anteverted placement is ideal placement in type C fractures. Fracture morphology in the sagittal plane should be taken into account in the lag screw placement.