Risk Stratification for Avascular Necrosis of the Femoral Head After Internal Fixation of Femoral Neck Fractures by Post-Operative Bone SPECT/CT

Purpose

Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN.

Methods

We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months.

Results

Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2–10 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively.

Conclusions

According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients.

     

Revisiting the indirect signs of a temporal bone fracture: air,air, everywhere

Background and purpose

The standard head CT protocol makes detection of a temporal bone fracture difficult. The purposes of our study are to revisit the finding of air in various locations around the temporal bone as an indirect sign of fracture and determine if findings could predict fracture pattern.

Materials and methods

We searched the radiology reports for the keyword “temporal bone fracture.” We recorded the presence of air in multiple locations around the temporal bone and pneumocephalus, opacification of the mastoid air cells or the middle ear cavity, and dominant fracture pattern. Statistical analyses were performed using statistical software.

Results

A total of 135 patients (mean age 40 ± 20.1 years, 101 male, 34 female, range 1–91) had 152 fractures. At least one indirect finding was present in 143 (94.1%) fractures. Air was present adjacent to the styloid process in 94 (61.8%), in the temporomandibular joint in 80 (52.6%), adjacent to the mastoid process in 57 (37.5%), and along the adjacent dural venous sinus in 33 (21.7%) fractures. Mastoid opacification was present in 139 (91.4%) fractures. Opacification of the middle ear cavity was present in 121 (79.6%) fractures. A complex fracture significantly and positively correlated with pneumocephalus.

Conclusion

In the setting of trauma, air around the temporal bone and opacification of the mastoid air cells or middle ear cavity should prompt consideration of a temporal bone fracture even if the fracture line is not visible. The presence of pneumocephalus predicts a higher chance of complex fracture pattern.

     

Computed tomography for occult fractures of the proximal femur,pelvis, and sacrum in clinical practice: single institution,dual-site experience

Purpose

The purpose of this study was to evaluate the diagnostic performance of CT for assessment of occult fractures of the proximal femur, pelvis, and sacrum.

Materials and methods

A retrospective review was performed on patients who received a CT of the hip or pelvis for suspected occult fracture after negative or equivocal radiographs performed within 24 h. The official radiology report was utilized for the determination of CT findings and calculation of sensitivity and specificity. Surgical reports, MRI reports, and clinical follow-up were used as the standard of reference. Sensitivity and specificity were calculated with 95% confidence intervals.

Results

Seventy-four patients received CT of the hip or pelvis for clinical concern for occult fracture after negative or equivocal radiographs. By the reference standard, a total of 40 fractures were present in 25/74 (33.8%) patients, including 35 conservatively treated fractures of the greater trochanter, pelvis, and sacrum, and 5 operatively treated proximal femoral fractures. A total of 14/74 (18.9%) of patients had an MRI within 1 day of CT. MRI identified an operatively treated femoral neck fracture not seen on CT and an operatively treated intertrochanteric fracture, which CT described as a greater trochanteric fracture. There were two false negative conservatively treated pelvic fractures not seen on CT but diagnosed on MRI. On a per-patient basis, CT had an overall sensitivity of 88% (22/25; 95% confidence intervals 69–97%), specificity of 98% (48/49; 95% confidence intervals 89–100%), and negative predictive value of 94%. For the five operative proximal femoral fractures, the sensitivity of CT was 60% (3/5; 95% confidence intervals 15–95%), specificity was 99% (68/69; 95% confidence intervals 92–100%), and negative predictive value was 97%.

Conclusions

In the clinical setting of suspected occult fracture, the sensitivity of clinical CT reports for detection of any type of fracture of the proximal femur, pelvis, or sacrum was 88%. For the small number of operatively treated proximal femoral fractures seen in the study, sensitivity of CT was 60% (3/5) and negative predictive value was 97%, although the relatively few patients needing fixation precludes statistical analysis.

     

CT characteristics of traumatic sacral fractures in association with pelvic ring injuries: correlation using the Young-Burgess classification system

Purpose

The purpose of the study is to determine the incidence of sacral fracture patterns on CT imaging of pelvic trauma patients with correlation with mechanism of injury and pelvic ring injury pattern using the Young-Burgess classification system.

Materials and methods

This is a retrospective review of all pelvic CTs with pelvic fractures performed at our level 1 trauma center during a 4-year period from July 2010 to June 2014.

Results

Sacral fractures were very common in pelvic trauma patients, being present in 60% of patients presenting to our institution with pelvic fractures. Longitudinal fractures were almost always associated with additional pelvic ring injuries. Denis zone 1 fractures had the highest association with lateral compression pelvic ring injuries. Denis zone 2 and 3 fractures were seen with increased frequency in AP compression and vertical shear injuries. A third of transverse sacral fractures occurred in isolation, with isolated transverse sacral fractures typically occurring in the low (S3–S5) sacrum. Almost half of combined transverse and longitudinal sacral fractures occurred without an additional pelvic fracture present. Sacral avulsions almost always occurred as part of a pelvic ring fracture pattern, most commonly in AP compression injuries. Coccyx fractures frequently occurred in isolation, but were commonly seen in vertical shear injuries when associated with a pelvic ring injury pattern.

Conclusion

Avulsion fractures and longitudinal fractures of the sacrum are almost always associated with anterior pelvic ring injury. Conversely, transverse fractures of the lower sacrum and combined longitudinal and transverse sacral fractures are prone to occur in isolation.

     

The posterior horn of the lateral meniscus is a reliable novel landmark for femoral tunnel placement in ACL reconstruction

Purpose

Femoral tunnel placement is essential for good outcome in anterior cruciate ligament (ACL) reconstruction. In the past, several attempts have been made to optimize femoral tunnel placement. It was observed that the posterior horn of the lateral meniscus was always located directly below to the desired femoral ACL tunnel position, when the knee was brought to deep flexion (>?120°). The goal of the present study was to verify the hypothesis that the posterior horn of the lateral meniscus can be used as a landmark for femoral tunnel placement.

Methods

Out of a consecutive series of ACL reconstructions done by a single surgeon, 55 lateral radiographs were evaluated according to the quadrant method by Bernard and Hertel. Additionally, on anterior-posterior radiographs the femoral tunnel angle was determined.

Results

In the present case series the posterior horn of the lateral meniscus could be identified and used as a landmark for femoral tunnel placement in all cases. The mean tunnel depth was 24?±?5.1% and the mean tunnel height was 31.3?±?5.7%. The mean femoral tunnel angle was 41?±?4.9° using the anatomical axis as a reference. Compared to previous cadaver studies the data of the present study were within their anatomical range of the native ACL insertion site.

Conclusion

The suggested technique using the posterior horn of the lateral meniscus as a landmark for femoral tunnel placement showed reproducible results and matches the native ACL insertion site compared to previous cadaveric studies. In particular, non-experienced ACL surgeons will benefit from this apparent landmark and the corresponding easy-to-use ACL reconstruction method.

Level of evidence

IV.

     

The anterolateral complex in anterior cruciate ligament deficient knees demonstrate sonographic abnormalities on high-resolution sonography

Purpose

The presence of anterolateral ligament of the knee is still controversial, and some physicians prefer to call this structure anterolateral complex (ALC) to infer plural nature of structures involved. The purpose of this study was to describe the scanning techniques and to classify various sonographic appearances of the tibial-side ALC of the knee in subjects with anterior cruciate ligament (ACL) injury. It was hypothesized that sonographic abnormity of the ALC would be associated with ACL injury history.

Methods

Patients with a history of unilateral ACL injury were prospectively recruited, and the ALC was sonographically evaluated. During the evaluation, the lateral femoral epicondyle was visualized in anatomic transverse view first. At this location, the ALC was typically most conspicuous between the short head of the biceps femoris muscle and the posterior and deep aspect of the iliotibial band superficial to the origin of the lateral collateral ligament. The ALC was followed distally to the broad insertion centralizing to the area posterior to Gerdy’s tubercle. The appearance of the distal insertion of the ALC was classified based both on echogenicity and on the presence of a Segond fracture as follows: Grade 0: isoechoic to the rest of the ALC, Grade 1: hypoechoic, Grade 2: anechoic, and Grade 3: Segond fracture. The uninjured side was similarly scanned for comparison.

Results

A total of 28 patients (13 men; mean age 22.1?±?8.1 years old with range: 12–44; mean body mass index 25.0 with range: 18.9–39.2) were included in this study. The average time from injury to sonograhpic evaluation was 4 months (range: 2 days to 1 year). Of 28 ACL-deficient knees, 19 were (68%) graded as Grade 0 in the distal insertion of the ALC, 7 (25%) as Grade 1, 1 (3.5%) as Grade 2, and 1 (3.5%) as Grade 3. Contralateral knees showed 25 knees (89%) with Grade 0 and 3 knees (11%) with Grade 1.

Conclusion

ACL injury history was associated with a higher incidence of sonographic abnormalities within the distal insertion of the anterolateral complex.

Level of evidence

III.

     

Fractures of the posterolateral maxillary sinus: a masticator space blowout injury?

Background and purpose

Segmental, depressed fractures of the posterolateral maxillary sinus may occur as a result of trauma to the masticator space, previously described in association with mandibular fractures. The authors hypothesize that the fracture is due to a transient increase in pressure in the masticator space (blow out) and therefore should be seen in association with other regional fractures.

Materials and methods

Injuries of the masticator space were retrospectively identified by searching the imaging database from January 2014 to November 2014 for keywords that would identify regional trauma. The images were reviewed for segmental depressed fractures in the posterolateral aspect of the maxillary sinus accompanied by herniation of a variable amount of masticator space fat and/or muscle into the adjacent sinus. Three neuroradiologists reviewed the images and agreed by consensus on the presence or absence of a masticator space blowout fracture.

Results

Forty-three zygomaticomaxillary complex (ZMC) fractures, 89 mandibular fractures, and 49 isolated zygomatic arch fractures were identified. While all of the ZMC fractures had a maxillary component, 3 of 43 (7.0 %) additional fractures met our fracture definition. Five of 89 (5.6 %) of the mandibular fractures and 6 of 49 (12.2 %) zygomatic arch fractures had an associated posterolateral maxillary fracture.

Conclusions

Segmental depressed fracture of the posterolateral maxillary sinus is relatively common, occurring in conjunction with other regional injuries. The authors hypothesize that it is due to a transient increase in pressure in the masticator space and is a separate entity from other fractures of the region that may occur concurrently.

     

Computed tomography compared to magnetic resonance imaging in occult or suspect hip fractures. A retrospective study in 44 patients

Background

Computed tomography (CT) for evaluation of occult and suspect hip fractures has been proposed as a good second-line investigation. The diagnostic precision compared to magnetic resonance imaging (MRI) is unclear.

Purpose

To compare the diagnostic performance of CT and MRI in a retrospective study on patients with suspect and occult hip fractures.

Material and methods

Forty-four elderly consecutive patients with low-energy trauma to the hip were identified where negative or suspect CT was followed by MRI. Primary reporting and review by two observers as well as the diagnostic performance of the two modalities were compared. Surgical treatment and clinical course were used as outcomes.

Results

Compared to the primary reports, the CT reviewers found fewer normal and no suspect cases. MRI changed the primary diagnoses in 27 cases, and in 14 and 15 cases, respectively, at review. There was no disagreement on MRI diagnoses.

Conclusion

In our patient population, MRI was deemed a more reliable modality for hip fracture diagnosis in comparison to CT. For clinical decision making, MRI seems to have a higher accuracy than CT. A negative CT finding cannot completely rule out a hip fracture in patients where clinical findings of hip fracture persevere.

Key Points

? Experience is highly influential in diagnosing occult or suspect hip fractures at CT ? Inconclusive hip CT shows high inter-rater reliability at experienced review ? There was low diagnostic accuracy via CT compared to MRI for all interpreters ? Hip fractures can readily be diagnosed at MRI regardless of radiological experience

     

Distracting injury defined: does an isolated hip fracture constitute a distracting injury for clearance of the cervical spine?

Objectives

As the population within the USA ages, the number of hip fractures seen yearly in the emergency department is expected to rise. According to the NEXUS criteria, many of these patients receive computerized tomographic scan (CT) evaluation of the cervical spine because a hip fracture may constitute a distracting injury. The objective of this study is to determine if an isolated hip fracture constitutes a distracting injury which requires imaging of the cervical spine.

Methods

Data were prospectively collected on 158 trauma patients with isolated hip fractures between April 1, 2015 and March 9, 2016. Patient demographics were analyzed and compared to the National Emergency X-Radiography Utilization Study (NEXUS).

Results

Patients with isolated hip fractures were predominantly elderly, on average 78.6 +/? 15.9 years old, and 94.3% of these injuries occurred after a fall from standing. Only one patient also had a cervical spine fracture which was not clinically significant. When compared to the established rate of cervical spine injury of 2.4%, the absolute risk reduction (ARR) was 0.35% (95% CI, ? 1.06 to 1.75%) and the number needed to treat (NNT) was 290.

Conclusion

In the case of an elderly patient with an isolated hip fracture and no cervical midline tenderness, cervical spine imaging may be reserved for those who have other NEXUS criteria for further workup.

     

Color postprocessing of conventional CT images: preliminary results in assessment of nondisplaced proximal femoral fractures

Purpose

The purpose of this study was to demonstrate the diagnostic performance and effect on reader confidence of a custom computed tomography (CT) color postprocessing algorithm for assessment of nondisplaced proximal femoral fractures.

Materials and methods

Four radiologists, including two PGY-3 radiology residents and two emergency radiologists, independently interpreted 30 CT examinations of the hip and/or pelvis performed for trauma, consisting of a total of 15 cases positive for nondisplaced hip fracture and 15 age and sex-matched controls. Images were reviewed first with conventional CT images and after at least 8 weeks, all images were reviewed again with the addition of coronal color postprocessed images. Sensitivity and specificity were compared with McNemar’s test, and diagnostic confidence was compared with paired t tests.

Results

There was no significant difference in diagnostic performance between conventional and postprocessed images, although there was nominally increased sensitivity and decreased specificity with the postprocessed images: for all readers, the sensitivity and specificity for conventional images was 88.3 and 95.0%, compared to 93.3% (p?=?0.25) and 88.3% (p?=?0.14) for postprocessed images. Three of four readers (including both attending radiologists) reported an increase in confidence with postprocessed images for cases negative for fracture (10-point confidence scale of 7.25 for conventional images, compared to 8.2 for postprocessed images for all readers, p?=?0.0053). There was no difference in diagnostic confidence for cases positive for fracture.

Conclusions

A custom color CT postprocessing algorithm did not demonstrate a significant difference in diagnostic performance for assessment of nondisplaced proximal femoral fractures within the limitations of a relatively small sample size; however, postprocessing increases confidence of experienced readers in cases negative for fracture.

     

The added value of cross-sectional imaging in the detection of additional radiographically occult fractures in the setting of a Chopart fracture

Purpose

Radiography has a low sensitivity for the detection of fractures related to the talonavicular and calcaneocuboid articulations, also known as Chopart fractures. The purpose of this study is to determine the sensitivity of radiographs for detecting additional foot and ankle fractures related to Chopart fracture using CT or MRI as the reference standard.

Method

We performed an IRB-approved, retrospective review of radiology reports between 2010 and 2014. Inclusion criteria were (1) diagnosis of a Chopart fracture and (2) at least one radiograph and subsequent cross-sectional imaging (CT or MR). CT or MRI was considered the diagnostic reference standard. Results were stratified by the energy of trauma and by type of radiograph performed (weight-bearing (WB) versus non-WB).

Results

One hundred eight patients met the inclusion criteria. The calcaneocuboid articulation was the most commonly involved type of Chopart fracture, seen in 75% of cases (81/108). Chopart fractures were detected on the initial radiographs in 67.6% of cases (73/108). Additional fractures of the ankle and midfoot were diagnosed in 34.2% of cases (37/108), with 56.7% (21/37) of these cases having at least one additional fracture seen on CT or MRI that was not seen on the initial radiographs, with fractures of the midfoot most often missed. In 56.7% (17/30) patients whose radiographs detected Chopart fractures, at least one additional fracture was missed; 30% of them demonstrated intra-articular extension and 56.7% were considered displaced. High-energy trauma was related to higher incidence of additional fractures. There was no significant difference in the sensitivity of radiographs to detect additional fractures between high versus low-energy trauma (p?=?0.3) and WB versus non-WB radiographs (p?=?0.5). Most patients were treated nonoperatively (56.5%, 61/108), with surgical intervention more frequent in patients with a high energy of trauma (51.7% versus 33.3%, p?=?0.05).

Conclusion

In the setting of a Chopart fracture, CT or MRI can add significant value in the detection of additional ankle or midfoot fractures, irrespective of the energy of trauma. Since additional fractures can have important management implications, CT or MRI should be considered as part of the standard workup for all midfoot fractures.

     

Percutaneous osteosynthesis in the pelvis in cancer patients

Purpose

Screw fixation (osteosynthesis) can be performed percutaneously by interventional radiologists. We report our experience in cancer patients.

Material/methods

We retrospectively reviewed all cases of percutaneous osteosynthesis (PO) of the pelvic ring and proximal femur performed in our hospital. PO were performed for fracture palliation or for osteolytic metastases consolidation. Screws were inserted under CT- or cone-beam CT- guidance and general anaesthesia. Patients were followed-up with pelvic-CT and medical consultation at 1 month, then every 3 months. For fractures, the goal was pain palliation and for osteolytic metastases, pathologic fracture prevention.

Results

Between February 2010 and August 2014, 64 cancer patients were treated with PO. Twenty-one patients had PO alone for 33 painful fractures (13 bone-insufficiency, 20 pathologic fractures). The pain was significantly improved at 1 month (VAS score?=?20/100 vs. 80/100). In addition, 43 cancer patients were preventively consolidated using PO plus cementoplasty for 45 impending pathologic fractures (10 iliac crests, 35 proximal femurs). For the iliac crests, no fracture occurred (median-FU?=?75 days). For the proximal femurs, 2 pathological fractures occurred (fracture rate?=?5.7 %, median-FU?=?205 days).

Conclusion

PO is a new tool in the therapeutic arsenal of interventional radiologists for bone pain management.

Key Points

? Screw fixation (osteosynthesis) can be performed percutaneously by interventional radiologists. ? CT- or CBCT-guidance results in high technical success rates for screw placement. ? This minimally invasive technique avoids extensive surgical exposure in bone cancer patients. ? Osteosynthesis provides pain relief for bone-insufficiency fractures and for pathologic fractures. ? Osteosynthesis plus cementoplasty provide prophylactic consolidation of impending pathological fractures.

     

Comparison of percutaneous long bone cementoplasty with or without embedding a cement-filled catheter for painful long bone metastases with impending fracture

Objective

To compare the efficacy of percutaneous long bone cementoplasty (PLBC) with and without embedding a cement-filled catheter in the medullary canal (ECFC) for painful long bone metastases with impending fracture.

Methods

A retrospective study was conducted in 36 consecutive patients undergoing PLBC and ECFC combination (n = 17, group A) or PLBC alone (n = 19, group B). All patients had a high risk of impending fracture in the long bone based on Mirels’ scoring system. Clinical effects were evaluated using both a pre- and a postoperative visual analogue scale (VAS) and Karnofsky performance scale (KPS).

Results

Overall pain relief rate with excellent (VAS 0–2) and good (VAS 2.5–4.5) results during follow-up was significantly higher in group A than in group B (88.2 % vs. 57.9 %, P<0.05). The average VAS and KPS changes in group A were significantly higher than those in group B at 1, 3 and 6 months postoperatively (P<0.05). Also, the rate of fractures of the treated long bone in group A was significantly lower than that in group B (P<0.05).

Conclusions

Combined PLBC and ECFC is a safe and effective procedure for long bone metastases with impending fracture.

Key Points

? Metastases in long bones may cause pain and subsequent pathological fractures. ? Cementoplasty resulted in significant pain relief in patients with long bone metastases. ? Combination of PLBC and ECFC may reduce the incidence of fractures.

     

Calcium phosphate-hybridized tendon grafts reduce femoral bone tunnel enlargement in anatomic single-bundle ACL reconstruction

Purpose

This study aimed to clarify the effect of calcium phosphate (CaP)-hybridized tendon grafting versus unhybridized tendon grafting on the morphological changes to the bone tunnels at the aperture 1 year after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction.

Methods

Seventy-three patients were randomized to undergo the CaP (n = 37) or the conventional method (n = 36). All patients underwent computed tomography (CT) evaluation 1 week and 1 year post-operatively. The femoral and tibial tunnels at the aperture were evaluated on reconstructed 3D CT images. Changes in the cross-sectional area (CSA) and diameters of the femur and the tibia, and the translation rate of the tunnel walls and the morphological changes of both tunnels were assessed.

Results

There was a significant reduction in the increase in the CSA and the anterior–posterior and proximal–distal tunnel diameters on the femoral side in the CaP group as compared with the conventional group. On the femoral side, the translation rate of the posterior wall was significantly larger in the CaP group than in the conventional group, whereas the translation rate of the distal wall was significantly smaller in the CaP group than in the conventional group.

Conclusions

As compared with the conventional method, the CaP-hybridized tendon graft reduced bone tunnel enlargement on the femoral side 1 year after anatomic single-bundle ACL reconstruction due to an anterior shift of the posterior wall and reduced distal shift in the femoral bone tunnel. Clinically, the CaP-hybridized tendon grafts can prevent femoral bone tunnel enlargement in anatomic single-bundle ACL reconstruction.

Level of evidence

I.

     

Long-Term Results from the MAJESTIC Trial of the Eluvia Paclitaxel-Eluting Stent for Femoropopliteal Treatment: 3-Year Follow-up

Purpose

To report the 3-year results of the MAJESTIC first-in-human study of the Eluvia Drug-Eluting Vascular Stent System for treating femoropopliteal artery lesions.

Methods

The prospective, single-arm, multicenter clinical trial enrolled 57 patients with symptomatic lower limb ischemia (Rutherford category 2, 3, or 4) and lesions in the superficial femoral artery or proximal popliteal artery. Mean lesion length was 70.8 ± 28.1 mm, and 46% of lesions were occluded. Efficacy measures at 2 years included primary patency, defined as duplex ultrasound peak systolic velocity ratio of ≤2.5 and the absence of target lesion revascularization (TLR) or bypass. Safety monitoring through 3 years included adverse events and TLR.

Results

Primary patency was estimated as 83.5% (Kaplan–Meier analysis) at 24 months, and 90.6% (48/53) of patients maintained an improvement in Rutherford class. At 36 months, the Kaplan–Meier estimate of freedom from TLR was 85.3%. No stent fractures were identified, and no major target limb amputations occurred.

Conclusion

MAJESTIC results demonstrated long-term treatment durability among patients whose femoropopliteal arteries were treated with the paclitaxel-eluting Eluvia stent.

Level of Evidence

Level 2b, cohort study

     

Improved stability with intramedullary stem after anterior femoral notching in total knee arthroplasty

Purpose

It has been hypothesized that femoral notching in total knee arthroplasties weakens the cortex of the femur, which can predispose to femoral fractures in the postoperative period. Some authors suggest that patients who sustain inadvertent notching should have additional protection in the postoperative period, and consideration should be given to the use of prophylactic femoral stems. In this case, a question can be raised: Is the use of femoral stem in an anterior femoral notching an effective way to reduce the fracture risk? We hypothesized that for a larger notch, the use of a femoral stem does not decrease considerably the stress-riser at the notch edge, and the use of stem is not enough to reduce the risk of fracture.

Methods

In the present in vitro study, twelve synthetic femurs were selected and used for the experiments under two load scenarios. Femoral components with and without femoral stems were implanted in femurs with different notch sizes to predict experimentally the strain levels at the notch edge with the use of fiber Bragg gratings and at notch region with strain gauges.

Results

Despite the global strain reduction in stemmed condition, at the notch edge, the strain behavior was dissimilar for the different notch depths. For notch depths lower than 5 mm, the use of stem reduces the strain level at the notch edge to values below the intact femur condition, while for depths greater or equal to 5 mm, the strain levels at the notch edge were higher than the intact femur condition with values ranging from +10 to +189%.

Conclusions

The present study suggests the use of a prophylactic stem for notch depths greater than 5 mm. For notch depths below 5 mm, the fracture risk due to strain increase at the notch edge seems to be low in the stemless condition.

     

Optimum stem length for mitigation of periprosthetic fracture risk following primary total knee arthroplasty: a finite element study

Purpose

Due to age-related changes to the material properties and thinning of the cortical bone structure, older patients with osteoporosis may be at greater risk of femoral fracture following total knee arthroplasty. This study investigates whether there is a potential role for stemmed prostheses in such scenarios to help mitigate peri-implant fracture risk, and if so what should the optimum stem length be to balance surgical bone loss with reduced fracture risk.

Methods

Finite element models of the distal femur implanted with four different implant types: a posterior stabilising implant, a total stabilising implant with short stem (12 mm × 50 mm), a TS implant with medium stem (12 mm × 75 mm), and a TS implant with long stem (12 mm × 100 mm), were developed and analysed in this study. Osteoporotic properties were applied to the implanted femurs and the periprosthetic stresses and strains of each were recorded.

Results

All stem lengths examined were found to lead to a reduction in periprosthetic stress in comparison with a primary stemless implant, with short-, medium-, and long-stemmed implants leading to an 11, 26, and 29% reduction in stress, respectively.

Conclusion

The results of this study show that periprosthetic stress and therefore fracture risk in old osteoporotic patients may be reduced through the use of stemmed femoral components. Of the three stems investigated, a medium-length stem is found to represent the best balance between bone preservation at the time of surgery and reduction in periprosthetic stress following implantation.

     

Fluoroscopic control allows for precise tunnel positioning in MPFL reconstruction

Purpose

In MPFL reconstruction, anatomical graft positioning is required to restore physiological joint biomechanics and patellofemoral stability. Considerable rates of non-anatomical femoral tunnel placement exist. The purpose of this study was to analyse whether intraoperative fluoroscopic control is applicable to reduce variability of femoral tunnel positioning.

Methods

Femoral tunnel positions of 116 consecutive MPFL reconstructions applying intraoperative fluoroscopic images were analysed. Tunnel positions were determined by two independent observers according to Schöttle’s radiographic measurement method. Mean positions, standard deviations and ranges were calculated to determine the variability of the tunnel positions. Interclass correlation coefficient (ICC) was calculated.

Results

The mean anterior/posterior distances from the anatomical insertion of the MPFL to the centre of the femoral tunnel were 2.34 mm (range 0.0–5.9 mm) and 1.7 mm (range 0.1–7.3 mm, SD 1.3) for proximal/distal deviations; 95.7 % (111/116) of femoral tunnel positions were found to be within the anatomical insertion area defined by Schöttle. Interobserver tunnel position measurements were highly reliable (ICC: depth 0.979; height 0.979).

Conclusion

The study demonstrates that intraoperative fluoroscopic control is a feasible and effective method that enables to create reproducible and precise anatomical femoral tunnel positions in MPFL reconstruction. Accordingly, the routine use of intraoperative fluoroscopy can be recommended. Furthermore, the results indicate Schöttle’s method as a reliable method for intraoperative control and postoperative analysis of femoral tunnel positioning.

Level of evidence

IV.

     

Unclassified MR arthrography pattern evaluation in patients with episodes of recurrent antero-inferior shoulder dislocation

Purpose

To evaluate prospectively the incidence of unclassifiable MR arthrography patterns of glenoid anterior–inferior labrum lesions, in patients with at least two episodes of recurrent antero-inferior shoulder dislocation.

Materials and methods

The MR shoulder Arthrography images of 36 patients, with at least two episodes of recurrent antero-inferior dislocation, were prospectively evaluated, during a period between November 2015 and Mai 2016. All patients were contacted after 6 months of the MR arthrography to evaluate their course of treatment. The MR arthrography images were analyzed by two radiologists, respectively with 5 and 15 years of experience in musculoskeletal radiology.

Results

36 cases of unclassifiable MR arthrography pattern of the anterior–inferior glenoid labrum were evaluated: in 13 out 36 cases (36.1%), the glenoid labrum has been described as “oedematous and swollen”; in 19 out 36 cases (52.8%), it has been described as “smooth” (not hypoplastic); in 4 out 36 cases (11.1%), it has been described as degenerated.

Conclusion

The unclassifiable MR arthrography patterns of fibrocartilage glenoid lesions after episodes of recurrent antero-inferior dislocation are commons. The unclassifiable MR arthrography patterns require a careful consideration, in order to improve the diagnostic and therapeutic multidisciplinary approach.

     

Surgical versus conservative management of acute patellar dislocation in children and adolescents: a systematic review

Purpose

The goal of this study was to perform a comparative review to determine whether there is a significant difference in the rate of repeat dislocation and clinical outcome between surgical and conservative management of acute patellar dislocation in children and adolescents.

Methods

A systematic review of the MEDLINE database was performed. English-language clinical outcome studies with a primary outcome/treatment specific to acute patella dislocation in a paediatric population were included. Eleven studies met inclusion criteria; Chi-square analysis, independent t tests and weighted mean pooled cohort statistics were performed where appropriate.

Results

A total of 470 conservatively managed and 157 operatively treated knees were included. Conservatively managed patients were on average 17.0 years and had a mean follow-up of 3.9 years; surgically managed patients were on average 16.1 years and had a mean follow-up of 4.7 years. Conservatively managed knees had a 31 % rate of recurrent dislocation rate compared to 22 % in surgical knees (p = 0.04). Trochlear dysplasia and skeletal immaturity confer greater risk for recurrent instability. Surgical treatment may provide clinically important quality of life and sporting benefit.

Conclusions

Surgical treatment of first time patella dislocation in children and adolescents is associated with a lower risk of recurrent dislocation and higher health-related quality of life and sporting function. There is a paucity of evidence on MPFL reconstruction for first time traumatic patella dislocation in this population.

Level of evidence

IV.