Standards for external fixation application: national survey under the auspices of the German Trauma Society

INTRODUCTION

External fixation is widely accepted as a provisional or sometimes definitive treatment for long-bone fractures. Indications include but are not limited to damage control surgery in poly-traumatized patients as well as provisional bridging to definite treatment with soft tissue at risk. As little is known about surgeon's habits in applying this treatment strategy, we performed a national survey.

METHODS

We utilized the member database of the German Trauma Society (DGU). The questionnaire encompassed 15 questions that addresses topics including participants' position, experience, workplace, and questions regarding specifics of external fixation application in different anatomical regions. Furthermore, we compared differences between trauma centre levels and surgeon-related factors.

RESULTS

The participants predominantly worked in level 1 trauma centres (42.7%) and were employed as attendings (54.7%). There was widespread consensus for planning and intra-operative radiographical control of external fixation. Surgeons appointed at a level I trauma centre preferred significantly more often supra-acetabular pin placement in external fixation of the pelvis rather than the utilization of iliac pins (75.8%, p = 0.0001). Moreover, they were more likely to favor a mini-open approach to insert humeral pins (42.4%, p = 0.003). Overall, blunt dissection and mini-open approaches seemed equally popular (38.2 and 34.1%). Department chairmen indicated more often than their colleagues to follow written pin-care protocols for minimization of infection (16.7%, p = 0.003).

CONCLUSION

Despite the fact that external fixation usage is widespread and well established among trauma surgeons in Germany, there are substantial differences in the method of application.

Medial acetabular wall breach in total hip arthroplasty - is full-weight-bearing possible?

BACKGROUND

A breach of the medial acetabular wall is a phenomenon seen frequently due to over-reaming during total hip arthroplasty (THA). The consequences of this issue are not fully understood particularly in cementless THA. A retrospective study was performed to answer whether: immediate postoperative full-weight-bearing in the presence of a medial acetabular wall breach after THA results in more short-term revisions of the acetabular component, and increases the risk for migration of the acetabular component?

HYPOTHESIS

Immediate full-weight-bearing in the presence of a medial breach is not associated with an increased likelihood for acetabular-related revision surgery or migration of the cup.

PATIENTS AND METHODS

In this retrospective cohort study, consecutive patients (n=95; mean age 68±13 years; 67 female) who underwent THA with an uncemented acetabular component were identified and a retrospective chart review was performed (follow-up 23±17 months, range 6 to 79 months). The presence of a postoperative radiographic medial acetabular breach was documented and the need for revision surgery and the rate of acetabular component migration were assessed during follow-up.

RESULTS

Some extent of radiographic medial acetabular wall breach was seen in 26/95 patients (27%). With regard to the primary outcome, 2/95 patients (2%) required revision surgery during follow-up. All revision surgeries occurred in the group without a medial breach (p=0.280) for causes related to the femoral or the head components. Persistent pain was present in 1/26 patients (3.8%) in the medial breach group and 8/69 patients in the control group (11.6%; p=0.436). In the radiographic follow-up (n=81), there was no significant difference between the control group and the medial breach group with regard to cup migration (Δ ilio-ischial overlap [distance between the ilio-ischial line and a parallel line tangential to the acetabular cup on AP views]: -0.5±0.9mm [range, -2.9 to 0.8] vs. -0.3±1.7mm [range, -1.9 to 2.2], Δ overlap tangent [defined as the distance between the two crossings of ilio-ischial line and the acetabular component on AP views]: -2.2±6.1mm [range, -21.4 to 0.0] vs. 0.4±6.9mm [range, -6.2 to 17.6]). Similarly, according to variation in the ilio-ischial overlap distance between postoperative and follow-up on pelvic AP views, 0/56 hips (0%) had cup migration ≥ 5mm in the control group versus 1/25 (4%) in the medial breach cohort (p=0.3).

DISCUSSION

In this retrospective observation of patients with immediate postoperative full-weight-bearing after THA, a radiographic breach of the medial acetabular wall was not associated with an increased risk for short-term revision surgery or radiographic migration at follow-up. According to the findings of this study and in the light of previous biomechanical studies, there is no clear evidence for postoperative partial weight-bearing in case of a medial breach as far as the surgeon feels that the acetabular component is stable.

LEVEL OF EVIDENCE

IV, Retrospective cohort study.

Assessment of polytraumatized patients according to the Berlin Definition: Does the addition of physiological data really improve interobserver reliability?

BACKGROUND

Several new definitions for categorizing the severely injured as the Berlin Definition have been developed. Here, severely injured patients are selected by additive physiological parameters and by the general Abbreviated Injury Scale (AIS)-based assessment. However, all definitions should conform to an AIS severity coding applied by an expert. We examined the dependence of individual coding on defining injury severity in general and in identifying polytrauma according to several definitions. A precise definition of polytrauma is important for quality management.

METHODS

We investigated the interobserver reliability (IR) between several polytrauma definitions for identifying polytrauma using several cut-off levels (ISS ≥16, ≥18, ≥20, ≥25 points, and the Berlin Definition). One hundred and eighty-seven patients were included for analyzing IR of the polytrauma definitions. IR for polytrauma definitions was assessed by Cohen's kappa.

RESULTS

IR for identifying polytrauma according to the relevant definitions showed moderate agreement (<0.60) in the ISS cutoff categories (ISS ≥16, ≥18, and ≥20 points), while ISS ≥25 points just reached substantial agreement (0.62) and the Berlin Definition demonstrated a correlation of 0.77 which is nearly perfect agreement (>0.80).

CONCLUSION

Compared with the ISS-based definitions of polytrauma, the Berlin Definition proved less dependent on the individual rater. This underlines the need to redefine the selection of severely injured patients. Using the Berlin Definition for identifying polytrauma could improve the comparability of patient data across studies, in trauma center benchmarking, and in quality assurance.

Imaging of Sacral Stress and Insufficiency Fractures

Fractures of the os sacrum without relevant trauma history are defined as stress or insufficiency fractures and often affect the anterior pelvis. Sacral insufficiency fractures are associated with osteoporosis and occur under physiological load. In contrast, sacral stress fractures are caused by mechanical overloading. Diagnostic confirmation is delayed in many of these patients. Thus, MRI and/or CT should be performed early. Fracture stability should be evaluated by CT. MRI is the better approach to rule out fractures and is highly sensitive. It is indicated in young patients and in patients with non-specific lumbosacral pain. Nuclear imaging techniques are viable alternatives in patients with a contraindication for MRI.

Recommendations for Diagnosis and Treatment of Fractures of the Ring of Axis

In a consensus process with four sessions in 2017, the working group “upper cervical spine” of the German Society for Orthopaedics and Trauma Surgery (DGOU) formulated “Therapeutic Recommendations for the Diagnosis and Treatment of Upper Cervical Fractures”, taking their own experience and the current literature into consideration. The following article describes the recommendations for axis ring fractures (traumatic spondylolysis C2). About 19 to 49% of all cervical spine injuries include the axis vertebra. Traumatic spondylolysis of C2 may include potential discoligamentous instability C2/3. The primary aim of the diagnostic process is to detect the injury and to determine potential disco-ligamentous instability C2/3. For classification purposes, the Josten classification or the modified Effendi classification may be used. The Canadian C-spine rule is recommended for clinical screening for C-spine injuries. CT is the preferred imaging modality and an MRI is needed to determine the integrity of the discoligamentous complex C2/3. Conservative treatment is appropriate in case of stable fractures with intact C2/3 motion segment (Josten type 2 and 2). Patients should be closely monitored, in order to detect secondary dislocation as early as possible. Surgical treatment is recommended in cases of primary severe fracture dislocation or discoligamentous instability C2/3 (Josten 3 and 4) and/or secondary fracture dislocation. Anterior cervical decompression and fusion (ACDF) C2/3 is the treatment of choice. However, in case of facet joint luxation C2/3 with looked facet (Josten 4), a primary posterior approach may be necessary.

[Quantification of treatment success for geriatric sacral fractures]

BACKGROUND

Geriatric sacral fractures represent an independent fracture entity of increasing incidence and growing socioeconomic relevance. The goals of treatment are very different to those in younger patients with high-energy pelvic fractures. Hence, new outcome measurement instruments are required in order to assess the success of treatment.

OBJECTIVE

Literature review summarizing existing concepts and providing an overview of outcome measurement instruments for geriatric sacral fractures.

METHODS

Narrative review article based on an analysis of the German and English-speaking literature from the last 10 years.

RESULTS

Geriatric sacral fractures result in impaired mobility, increased physical and social loss of dependency and increased morbidity and mortality rates. There is a lack of standardized specific assessment procedures for functional outcome measurement after geriatric sacral fractures. Until these are developed and validated, a parallel acquisition of mortality, the timed up and go test, the Oswestry disability index (ODI) and a generic healthcare questionnaire score (SF-36, EQ-5D) seem to be most suitable.

CONCLUSION

At present our knowledge about the natural course of geriatric sacral fractures is limited by the lack of well-validated instruments to measure functional and radiographic outcomes. This has to be considered when evaluating the success of new treatment options for these patients. Future studies should validate existing scores for this population and develop new specific outcome instruments.

CT-based evaluation of volumetric bone density in fragility fractures of the pelvis-a matched case-control analysis

This matched case-control study compared the computed tomography (CT)-based regional bone density of patients with fragility fractures of the sacrum to a control without fracture. Patients with a sacral fracture demonstrated a significantly lower regional bone density of the sacrum, the sacral bone density not being correlated with the BMD by DXA of the spine.

INTRODUCTION

The aim of this study is to compare the computed tomography-based regional bone density measured by Hounsfield units (HUs) in patients with and without fragility fractures of the sacrum.

METHODS

Patients aged ≥ 50 years with a fragility fracture of the sacrum were compared to patients of similar age and gender who had a fall from standing height without fracture (n = 46). A matched case-control analysis was conducted by retrospective chart review and assessment of areal bone mineral density by lumbar DXA and by volumetric regional HU measurements in uncalibrated CT scans of the sacrum.

RESULTS

Patients with a sacral fracture (age 74 ± 11 years) showed a lower bone density in the body of S1 (HU 85 ± 22) when compared to the matched control group without fracture (age 73 ± 10 years, HU 125 ± 37, p < 0.001). The CT-based bone density of S1 did not correlate with the DXA values of the lumbar spine (r = 0.223, p = 0.136), and lumbar spine T-scores did not differ between the groups (- 2.0 ± 1.3 vs. - 1.9 ± 1.2, p = 0.786). All measurements are based on uncalibrated scans, and absolute HU values are restricted to scans made on Siemens SOMATOM Force or SOMATOM Edge scanners.

CONCLUSIONS

Patients with fragility fractures of the sacrum demonstrated a lower regional volumetric bone density of the sacrum when compared to a cohort without a fracture. Local sacral volumetric bone density as measured by CT seems to be independent from the areal BMD as measured by DXA of the lumbar spine.

LEVEL OF EVIDENCE

level III.

[Abdominal injuries in polytraumatized adults : Systematic review]

Abdominal injuries are potentially life-threatening and occur in 20-25% of all polytraumatized patients. Blunt trauma is the main mechanism. The liver and spleen are most commonly injured and much less often the intestines. The clinical evaluation proves equivocal in many cases; therefore, the gold standard is computed tomography (CT), which has been increasingly used even in hemodynamically weakly stable or sometimes even unstable patients because it promptly provides precise diagnostic findings, which present the basis for successful therapy. Hemodynamically unstable patients always need an exploratory laparotomy (EL). An EL should also be carried out with a positive focused assessment with sonography for trauma (FAST) or CT for severe parenchymal lesions, hollow organ lesions, intraperitoneal bladder lesions, peritonitis and organ evisceration, impalement injuries and lesions of the abdominal fascia. Hemodynamically stable patients without signs of peritonitis and a lack of such findings can often be treated conservatively irrespective of the extent of an injury. Angiography (and if needed embolization) can additionally be diagnostically and therapeutically utilized.

Normative values for CT-based texture analysis of vertebral bodies in dual X-ray absorptiometry-confirmed, normally mineralized subjects

OBJECTIVES

To develop age-, gender-, and regional-specific normative values for texture analysis (TA) of spinal computed tomography (CT) in subjects with normal bone mineral density (BMD), as defined by dual X-ray absorptiometry (DXA), and to determine age-, gender-, and regional-specific differences.

MATERIALS AND METHODS

In this retrospective, IRB-approved study, TA was performed on sagittal CT bone images of the thoracic and lumbar spine using dedicated software (MaZda) in 141 individuals with normal DXA BMD findings. Numbers of female and male subjects were balanced in each of six age decades. Three hundred and five TA features were analyzed in thoracic and lumbar vertebrae using free-hand regions-of-interest. Intraclass correlation (ICC) coefficients were calculated for determining intra- and inter-observer agreement of each feature. Further dimension reduction was performed with correlation analyses.

RESULTS

The TA features with an ICC < 0.81 indicating compromised intra- and inter-observer agreement and with Pearson correlation scores r > 0.8 with other features were excluded from further analysis for dimension reduction. From the remaining 31 texture features, a significant correlation with age was found for the features mean (r = -0.489, p < 0.001), variance (r = -0.681, p < 0.001), kurtosis (r = 0.273, p < 0.001), and WavEnLL_s4 (r = 0.273, p < 0.001). Significant differences were found between genders for various higher-level texture features (p < 0.001). Regional differences among the thoracic spine, thoracic-lumbar junction, and lumbar spine were found for most TA features (p < 0.021).

CONCLUSION

This study established normative values of TA features on CT images of the spine and showed age-, gender-, and regional-specific differences in individuals with normal BMD as defined by DXA.

Anterior subcutaneous internal fixation of the pelvis - what rod-to-bone distance is anatomically optimal?

INTRODUCTION

Anterior fixation of the pelvis using subcutaneous supra-acetabular pedicle screw internal fixation (INFIX) has proven to be a useful tool by avoiding the downsides of external fixation in patients where open fixation is not suited. The purpose of this study was to find a rod-to-bone distance for the INFIX that allows for minimal hazard to the inguinal neuro-vascular structures and, at the same time, as little as possible interference with the soft tissues of the proximal thigh when the patient is sitting.

METHODS

An INFIX was applied to 10 soft-embalmed cadaver pelvises with three different rod-to-bone distances. With each configuration, the relations of the rod to the neuro-vascular and the muscular surroundings were measured in supine and sitting position.

RESULTS

Except for the femoral artery, vein and nerve, all investigated anatomical structures of the groin were under compression with a rod-to-bone distance of 1cm. With a rod-to-bone distance of 2cm most of the anatomical structures were safe in supine position, although less than with 3cm. With hip flexion some structures got under compression, especially the lateral femoral cutaneous nerve (LFCN, 80%) and the anterior cutaneous branches of the femoral nerve (ACBFN, 35%). With a rod-to-bone distance of 3cm almost all anatomical structures were safe in supine position, while with hip flexion most superficial structures of the proximal thigh got under compression, especially the LFCN (75%) and the ACBFN (60%).

CONCLUSIONS

Aiming for a rod-to-bone distance of 2cm is the safest way with regard to compression of the femoral neuro-vascular bundle and at the same time leads to the least compression of more superficial structures like the LFCN, the ACBFN, or the sartorius and the rectus femoris muscles in sitting position.

Current concepts in locking plate fixation of proximal humerus fractures

Despite numerous available treatment strategies, the management of complex proximal humeral fractures remains demanding. Impaired bone quality and considerable comorbidities pose special challenges in the growing aging population. Complications after operative treatment are frequent, in particular loss of reduction with varus malalignment and subsequent screw cutout. Locking plate fixation has become a standard in stabilizing these fractures, but surgical revision rates of up to 25% stagnate at high levels. Therefore, it seems of utmost importance to select the right treatment for the right patient. This article provides an overview of available classification systems, indications for operative treatment, important pathoanatomic principles, and latest surgical strategies in locking plate fixation. The importance of correct reduction of the medial cortices, the use of calcar screws, augmentation with bone cement, double-plate fixation, and auxiliary intramedullary bone graft stabilization are discussed in detail.

A Cost-Effectiveness Analysis of Reverse Total Shoulder Arthroplasty versus Hemiarthroplasty for the Management of Complex Proximal Humeral Fractures in the Elderly

BACKGROUND

There is ongoing debate regarding the optimal surgical treatment of complex proximal humeral fractures in elderly patients.

OBJECTIVES

To evaluate the cost-effectiveness of reverse total shoulder arthroplasty (RTSA) compared with hemiarthroplasty (HA) in the management of complex proximal humeral fractures, using a cost-utility analysis.

METHODS

On the basis of data from published literature, a cost-utility analysis was conducted using decision tree and Markov modeling. A single-payer perspective, with a willingness-to-pay (WTP) threshold of Can$50,000 (Canadian dollars), and a lifetime time horizon were used. The incremental cost-effectiveness ratio (ICER) was used as the study's primary outcome measure.

RESULTS

In comparison with HA, the incremental cost per quality-adjusted life-year gained for RTSA was Can$13,679. One-way sensitivity analysis revealed the model to be sensitive to the RTSA implant cost and the RTSA procedural cost. The ICER of Can$13,679 is well below the WTP threshold of Can$50,000, and probabilistic sensitivity analysis demonstrated that 92.6% of model simulations favored RTSA.

CONCLUSIONS

Our economic analysis found that RTSA for the treatment of complex proximal humeral fractures in the elderly is the preferred economic strategy when compared with HA. The ICER of RTSA is well below standard WTP thresholds, and its estimate of cost-effectiveness is similar to other highly successful orthopedic strategies such as total hip arthroplasty for the treatment of hip arthritis.

Bacterial reduction and shift with NPWT after surgical debridements: a retrospective cohort study

BACKGROUND

Surgical debridement, negative-pressure wound therapy (NPWT) and antibiotics are used for the treatment of open wounds. However, it remains unclear whether this treatment regimen is successful in the reduction and shift of the bacterial load.

METHODS

After debridement in the operating room, NPWT, and antibiotic treatment, primary and secondary consecutive microbiological samples of 115 patients with 120 open wounds with bacterial or yeast growth in ≥1 swab or tissue microbiological sample(s) were compared for bacterial growth, Gram staining and oxygen use at a level one trauma center in 2011.

RESULTS

Secondary samples had significantly less bacterial growth (32 vs. 89%, p < .001, OR 17), Gram-positive bacteria (56 vs. 78%, p = .013), facultative anaerobic bacteria (64 vs. 85%, p = .011) and Staphylococcus aureus (10 vs. 46%, p = .002). They also tended to include relatively more Coagulase-negative Staphylococci (CoNS) (44 vs. 18%) and Pseudomonas species (spp.) (31 vs. 7%). Most (98%) wounds were successfully closed within 11 days, while wound revision was needed in 4%.

CONCLUSIONS

The treatment regimen of combined use of repetitive debridement, irrigation and NPWT in an operating room with antibiotics significantly reduced the bacterial load and led to a shift away from Gram-positive bacteria, facultative anaerobic bacteria, and S. aureus, as well as questionably toward CoNS and Pseudomonas spp. in this patient cohort. High rates of wound closure were achieved in a relatively short time with low revision rates. Whether each modality played a role for these findings remains unknown.

Outcome after protected full weightbearing treatment in an orthopedic device in diabetic neuropathic arthropathy (Charcot arthropathy): a comparison of unilaterally and bilaterally affected patients

Background

Charcot neuropathic arthropathy (CN) is a chronic, progressive, destructive, non-infectious process that most frequently affects the bone architecture of the foot in patients with sensory neuropathy. We evaluated the outcome of protected weightbearing treatment of CN in unilaterally and bilaterally affected patients and secondarily compared outcomes in protected versus unprotected weightbearing treatment.

Methods

Patient records and radiographs from 2002 to 2012 were retrospectively analyzed. Patients with Type 1 or Type 2 diabetes with peripheral neuropathy were included. Exclusion criteria included immunosuppressive or osteoactive medication and the presence of bone tumors. Ninety patients (101 ft), mean age 60.7 ± 10.6 years at first diagnosis of CN, were identified. Protected weightbearing treatment was achieved by total contact cast or custom-made orthosis. Ulcer, infection, CN recurrence, and amputation rates were recorded. Mean follow-up was 48 (range 1–208) months.

Results

Per the Eichenholtz classification, 9 ft were prodromal, 61 in stage 1 (development), 21 in stage 2 (coalescence) and 10 in stage 3 (reconstruction). Duration of protected weightbearing was 20 ± 21 weeks and 22 ± 29 weeks in patients with unilateral and bilateral CN, respectively. In bilaterally affected patients, new ulcers developed in 9/22 (41%) feet. In unilaterally affected patients, new ulcers developed in 5/66 (8%) protected weightbearing feet and 4/13 (31%) unprotected, full weightbearing feet (p = 0.036). The ulceration rate was significantly higher in bilaterally versus unilaterally affected patients with a protected weightbearing regimen (p = 0.004). Soft tissue infection occurred in 1/13 (8%) unprotected weightbearing feet and 1/66 (2%) protected weightbearing feet in unilaterally affected patients, and in 1/22 (4%) protected weightbearing feet of bilaterally affected patients. Recurrence and amputation rates were similar across treatment modalities.

Conclusions

Bilateral CN results in significantly more ulcers than unilateral CN and leads to slightly higher soft tissue infections. Protected weightbearing in an orthopedic device can reduce the risk for complications in acute CN of the foot and ankle.

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

BACKGROUND

Sacroiliac screw fixation in elderly patients with pelvic fractures is prone to failure owing to impaired bone quality. Cement augmentation has been proposed as a possible solution, because in other anatomic areas this has been shown to reduce screw loosening. However, to our knowledge, this has not been evaluated for sacroiliac screws.

QUESTIONS/PURPOSES

We investigated the potential biomechanical benefit of cement augmentation of sacroiliac screw fixation in a cadaver model of osteoporotic bone, specifically with respect to screw loosening, construct survival, and fracture-site motion.

METHODS

Standardized complete sacral ala fractures with intact posterior ligaments in combination with ipsilateral upper and lower pubic rami fractures were created in osteoporotic cadaver pelves and stabilized by three fixation techniques: sacroiliac (n = 5) with sacroiliac screws in S1 and S2, cemented (n = 5) with addition of cement augmentation, and transsacral (n = 5) with a single transsacral screw in S1. A cyclic loading protocol was applied with torque (1.5 Nm) and increasing axial force (250-750 N). Screw loosening, construct survival, and sacral fracture-site motion were measured by optoelectric motion tracking. A sample-size calculation revealed five samples per group to be required to achieve a power of 0.80 to detect 50% reduction in screw loosening.

RESULTS

Screw motion in relation to the sacrum during loading with 250 N/1.5 Nm was not different among the three groups (sacroiliac: 1.2 mm, range, 0.6-1.9; cemented: 0.7 mm, range, 0.5-1.3; transsacral: 1.1 mm, range, 0.6-2.3) (p = 0.940). Screw subsidence was less in the cemented group (3.0 mm, range, 1.2-3.7) compared with the sacroiliac (5.7 mm, range, 4.7-10.4) or transsacral group (5.6 mm, range, 3.8-10.5) (p = 0.031). There was no difference with the numbers available in the median number of cycles needed until failure; this was 2921 cycles (range, 2586-5450) in the cemented group, 2570 cycles (range, 2500-5107) for the sacroiliac specimens, and 2578 cycles (range, 2540-2623) in the transsacral group (p = 0.153). The cemented group absorbed more energy before failure (8.2 × 10⁵ N*cycles; range, 6.6 × 10⁵-22.6 × 10⁵) compared with the transsacral group (6.5 × 10⁵ N*cycles; range, 6.4 × 10⁵-6.7 × 10⁵) (p = 0.016). There was no difference with the numbers available in terms of fracture site motion (sacroiliac: 2.9 mm, range, 0.7-5.4; cemented: 1.2 mm, range, 0.6-1.9; transsacral: 2.1 mm, range, 1.2-4.8). Probability values for all between-group comparisons were greater than 0.05.

CONCLUSIONS

The addition of cement to standard sacroiliac screw fixation seemed to change the mode and dynamics of failure in this cadaveric mechanical model. Although no advantages to cement were observed in terms of screw motion or cycles to failure among the different constructs, a cemented, two-screw sacroiliac screw construct resulted in less screw subsidence and greater energy absorbed to failure than an uncemented single transsacral screw.

CLINICAL RELEVANCE

In osteoporotic bone, the addition of cement to sacroiliac screw fixation might improve screw anchorage. However, larger mechanical studies using these findings as pilot data should be performed before applying these preliminary findings clinically.

The Radiographic Union Score for Hip (RUSH) Identifies Radiographic Nonunion of Femoral Neck Fractures

BACKGROUND

The Radiographic Union Score for Hip (RUSH) is a previously validated outcome instrument designed to improve intra- and interobserver reliability when describing the radiographic healing of femoral neck fractures. The ability to identify fractures that have not healed is important for defining nonunion in clinical trials and predicting patients who will likely require additional surgery to promote fracture healing. We sought to investigate the utility of the RUSH score to define femoral neck fracture nonunion.

QUESTIONS/PURPOSES

(1) What RUSH score threshold yields at least 98% specificity to diagnose nonunion at 6 months postinjury? (2) Using the threshold identified, are patients below this threshold at greater risk of reoperation for nonunion and for other indications?

METHODS

A representative sample of 250 out of a cohort of 725 patients with adequate 6-month hip radiographs was analyzed from a multinational elderly hip fracture trial (FAITH). All patients had a femoral neck fracture and were treated with either multiple cancellous screws or a sliding hip screw. Two reviewers independently determined the RUSH score based on the 6-month postinjury radiographs and interrater reliability was assessed with the interclass correlation coefficient (ICC). There was substantial reliability between the reviewers assigning the RUSH scores (ICC, 0.81; 95% confidence interval [CI], 0.76-0.85). The RUSH score is a checklist-based system that quantifies four measures of healing: cortical bridging, cortical fracture disappearance, trabecular consolidation, and trabecular fracture disappearance.. Fracture healing was determined by two independent methods: (1) concurrently by the treating surgeon using both clinical and radiographic assessments as per routine clinical care; and (2) retrospectively by a Central Adjudication Committee using complete obliteration of the fracture line on radiographs alone. Receiver operating characteristic tables were used to define a RUSH threshold score that was > 98% specific for fracture nonunion.

RESULTS

A threshold score of < 18 was associated with a 100% specificity (95% CI, 97%-100%) and a positive predictive value of 100% (95% CI, 73%-100%) for radiographic nonunion. In contrast, using the fracture healing assessments of the treating surgeons failed to identify a useful discriminatory nonunion threshold and the highest positive predictive value was 43%. With respect to complications, patients with RUSH scores below 18 had greater risk of undergoing reoperation for nonunion (reoperation when < 18: six of 13 [46%]; reoperation when ≥ 18: 11 of 237 [54%]; relative risk [RR], 9.9 [95% CI, 4.4-22.7]; p < 0.001) and for all indications (reoperation when < 18: eight of 13 [62%]; reoperation when ≥ 18: 54 of 237 [38%]; RR, 2.7 [95% CI, 1.7-4.4]; p = 0.004).

CONCLUSIONS

The 6-month RUSH score is a reliable method for assessing radiographic healing. Our results highlight the discordance between radiographic determinations and clinician assessments of fracture healing and stress the need for clinical data to be incorporated in research studies evaluating fracture healing.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Bone mechanical properties and changes with osteoporosis

This review will define the role of collagen and within-bone heterogeneity and elaborate the importance of trabecular and cortical architecture with regard to their effect on the mechanical strength of bone. For each of these factors, the changes seen with osteoporosis and ageing will be described and how they can compromise strength and eventually lead to bone fragility.

Assessment of functional outcomes of surgically managed acetabular fractures

We performed a systematic review of the literature pertaining to the functional outcomes of the surgical management of acetabular fractures. A total of 69 articles met our inclusion criteria, revealing that eight generic outcome instruments were used, along with five specific instruments. The majority of studies reported outcomes using a version of the d’Aubigne and Postel score, which has not been validated for use in acetabular fracture. Few validated outcome measures were reported. No psychometric testing of outcome instruments was performed. The current assessment of outcomes in surgery for acetabular fractures lacks scientific rigour, and does not give reliable outcome data for either scientific comparison or patient counselling.

Take home message: The use of non-validated functional outcome measures is a major limitation of the current literature pertaining to surgical management of acetabular fractures; future studies should use validated outcome measures to ensure the legitimacy of the reported results.

Cite this article: Bone Joint J 2016;98-B:690–5.

Inclination-dependent changes of the critical shoulder angle significantly influence superior glenohumeral joint stability

BACKGROUND

The critical shoulder angle combines the acromion index and glenoid inclination and has potential to discriminate between shoulders at risk for rotator cuff tear or osteoarthritis and those that are asymptomatic. However, its biomechanics, and particularly the role of the glenoid inclination, are not yet fully understood.

METHODS

A shoulder simulator was used to analyze the independent influence of glenoid inclination during abduction from 0 to 60°. Spindle motors transferred tension forces by a cable-pulley on human cadaveric humeri. A six-degree-of-freedom force transducer was mounted directly behind the polyethylene glenoid to measure shear and compressive joint reaction force and calculate the instability ratio (ratio of shear and compressive joint reaction force) with the different force ratios of the deltoid and supraspinatus muscles (2:1 and 1:1). A stepwise change in the inclination by 5° increments allowed simulation of a critical shoulder angle range of 20° to 45°.

FINDINGS

Tilting the glenoid to cranial (increasing the critical shoulder angle) increases the shear joint reaction force and therefore the instability ratio. A balanced force ratio (1:1) between the deltoid and the supraspinatus allowed larger critical shoulder angles before cranial subluxation occurred than did the deltoid-dominant ratio (2:1).

INTERPRETATION

Glenoid inclination-dependent changes of the critical shoulder angle have a significant impact on superior glenohumeral joint stability. The increased compensatory activity of the rotator cuff to keep the humeral head centered may lead to mechanical overload and could explain the clinically observed association between large angles and degenerative rotator cuff tears.

[Pelvic Ring Fractures in the Elderly]

Pelvic ring fractures in elderly patients are usually associated with a low-energy trauma, which may hide the fact that these fractures are often a combination of anterior and posterior pelvic ring injuries with a potential significant instability with subsequent pain and immobility. Pelvic fractures in the geriatric population are associated with a high morbidity and mortality. The goals of any treatment are the restoration of mobility and independency as well as the prevention of future fractures. In order to accomplish these goals, an interdisciplinary approach is indispensable. This review is aimed to provide insight into the characteristics of geriatric pelvic ring injuries and into their diagnosis and therapy with the associated outcome.

Correlation of pelvic incidence with radiographical parameters for acetabular retroversion: a retrospective radiological study

Background

Pelvic incidence (PI) has been linked to several degenerative processes within the spinopelvic system. Acetabular retroversion is a recognised risk factor for osteoarthritis of the hip. We therefore hypothesised that these two factors might be part of a specific anatomical variant associated with degenerative changes. This study was performed to clarify this issue.

Methods

The pelvic incidence was measured on 589 computertomographical data sets acquired between 2008 and 2010. For 220 patients a 2D rendering in an antero-posterior view of the CT data set was performed to evaluate the parameters of acetabular retroversion. Those included the prominence of the ischial spine sign (PRISS), the cross-over sign (COS) and the posterior wall sign (PWS). Between 477 and 478 hips were evaluated depending on the parameter of retroversion.

Results

The mean pelvic incidence was significantly lower in hips positive for the PRISS and the PWS. However, there were no significant differences between hips positive or negative for the COS.

Discussion

As hypothesised, the lower PI values in PWS and PRISS positive hips suggest a link between PI and retroversion of the acetabulum. Whether this is of any clinical relevance remains, however, unknown.

Conclusion

Acetabular retroversion is linked to PI. In hips where the prominence of the ischial spine sign and/or the posterior wall sign was present, the mean pelvic incidence value was lower.

Incidence, Magnitude, and Predictors of Shortening in Young Femoral Neck Fractures

OBJECTIVES

To describe the incidence and magnitude of femoral neck fracture shortening in patients age younger than 60 years. Secondarily, to examine predictors of fracture shortening.

DESIGN

Retrospective chart review.

SETTING

Level I trauma centre.

PATIENTS/PARTICIPANTS

Sixty-five patients with a median age of 51 years (interquartile range: 42-56 years) were included. Seventy-one percent were male, 75% were displaced fractures, and 78% were treated with cancellous screws.

INTERVENTION

Internal fixation with multiple cancellous screws or sliding hip screw (SHS) + derotation screw.

MAIN OUTCOME MEASUREMENTS

Radiographic femoral neck shortening at a minimum of 6 weeks after fixation.

RESULTS

Fifty-four percent of patients had ≥5 mm of femoral neck shortening (22% had between ≥5 and <10 mm and 32% ≥10 mm). Initially, displaced fractures shortened more than undisplaced fractures (mean: 8.1 vs. 2.2 mm, P < 0.001), and fractures treated with SHS + derotation screw shortened more than fractures with cancellous screws alone (10.7 vs. 5.5 mm, P = 0.03). Even when adjusting for initial fracture displacement, fractures treated with SHS + derotation screw shortened an average of 2.2 mm more than fractures treated with screws alone (P = 0.03).

CONCLUSIONS

The incidence of clinically significant shortening in our young femoral neck fracture population was higher than anticipated, and 32% of patients experienced severe shortening of >1 cm. Our findings highlight the need for further research to determine the impact of severe shortening on functional outcome and to determine if implant selection affects fracture shortening.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The "Down the PC" view - A new tool to assess screw positioning in the posterior column of the acetabulum

INTRODUCTION

Minimal-invasive placement of screws into the posterior column of the acetabulum (PC) is challenging. Due to the saddle-shaped curvature of the medial cortical border of the PC, the standard fluoroscopic views of the pelvis cannot provide the desired safety during screw insertion. The aim of this study was to define a view tangentially to the medial cortex of the PC and to evaluate its accuracy and inter-observer reproducibility.

METHODS

Radio-dense markers on the medial cortex of the PC along the axis of a PC screw were brought in line and landmarks of the new "Down the PC" view were determined. Kirschner wires were placed into the PC of a pelvis composite model and five pelvic cadaver specimens in a total of 34 different correct and incorrect positions. Based on either only the "Down the PC" view, only the standard views, or a combination of both, three fellowship-trained orthopaedic surgeons had to decide if the inserted wires were in bone in the posterior column or had exited cortex, and if they penetrated the acetabulum. Sensitivity, specificity, and the intra-class correlation coefficient were calculated.

RESULTS

A view using three radiographic landmarks (pelvic brim, medial cortical wall of the body of the ischium, ischial spine) was found. Sensitivity and specificity to detect perforation out of the bone were 1.00 and 0.97 for the "Down the PC" view, 0.46 and 0.97 if only the standard views were used, and 1.00 and 0.95 for a combination of both. Sensitivity and specificity to detect intra-articular wire placement were 1.00 and 0.96 for the "Down the PC" view, 0.72 and 0.95 if only the standard views were used, and 0.94 and 0.99 for a combination of both. Inter-observer agreement using only the "Down the PC" view was excellent with an ICC of 0.92 for perforation and ICC of 0.82 for intra-articular wire placement.

CONCLUSIONS

The "Down the PC" view is a useful addendum in the orthopaedic trauma surgeon's tool box. Using simple landmarks, it is easily to reproduce and thereby shows excellent accuracy and inter-observer agreement in order to detect medial perforation or intra-articular implant position.

[Sacroiliac joint pain - diagnostic algorithm and therapeutic approaches]

The sacroiliac joints are causative for 13-30% of cases with low back pain and are still disregarded in the differential diagnosis. This is mainly due to its complex anatomy and the variety of pain patterns originating from the SI joints. The broad etiology of low back pain often misleads the physician into inadequate treatments. This article reviews the clinical presentation of patients suffering from a sacroiliac arthropathy and points out therapeutic strategies. It also provides a helpful diagnostic tool in daily routine. Eventually, any patient needs to experience a significant pain reduction resulting from an intrarticular injection before the diagnosis of non-inflammatory SI arthropathy is confirmed. In most cases, nonoperative treatment measures are sufficient. Operative strategies are available in selected cases with unsuccessful conservative therapy.

Comparing the predictive value of the pelvic ring injury classification systems by Tile and by Young and Burgess

INTRODUCTION

Radiology-based classifications of pelvic ring injuries and their relevance for the prognosis of morbidity and mortality are disputed in the literature. The purpose of this study was to evaluate potential differences between the pelvic ring injury classification systems by Tile and by Young and Burgess with regard to their predictive value on mortality, transfusion/infusion requirement and concomitant injuries.

PATIENTS AND METHODS

Two-hundred-and-eighty-five consecutive patients with pelvic ring fractures were analyzed for mortality within 30 days after admission, number of blood units and total volume of fluid infused during the first 24h after trauma, the Abbreviated Injury Severity (AIS) scores for head, chest, spine, abdomen and extremities as a function of the Tile and the Young-Burgess classifications.

RESULTS

There was no significant relationship between occurrence of death and fracture pattern but a significant relationship between fracture pattern and need for blood units/total fluid volume for Tile (p<.001/p<.001) and Young-Burgess (p<.001/p<.001). In both classifications, open book fractures were associated with more fluid requirement and more severe injuries of the abdomen, spine and extremities (p<.05). When divided into the larger subgroups "partially stable" and "unstable", unstable fractures were associated with a higher mortality rate in the Young-Burgess system (p=.036). In both classifications, patients with unstable fractures required significantly more blood transfusions (p<.001) and total fluid infusion (p<.001) and higher AIS scores.

CONCLUSIONS

In this first direct comparison of both classifications, we found no clinical relevant differences with regard to their predictive value on mortality, transfusion/infusion requirement and concomitant injuries.

Mechanical testing of a device for subcutaneous internal anterior pelvic ring fixation versus external pelvic ring fixation

Background

Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with pin tract infections, the patient’s limited mobility and a restricted surgical accessibility to the lower abdomen. In this study, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated.

Methods

A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders using a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz with sinusoidal lateral compression/distraction (+/−50 N) and torque (+/− 0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles.

Results

There was no significant difference in translational stiffness between the SIAF and the standard external fixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the SIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005) cycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen.

Conclusions

In comparison with the standard external fixation system, the tested device for subcutaneous internal anterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness.

Anterior subcutaneous internal fixation for treatment of unstable pelvic fractures

BACKGROUND

Fractures of the pelvic ring including disruption of the posterior elements in high-energy trauma have both high morbidity and mortality rates. For some injury pattern part of the initial resuscitation includes either external fixation or plate fixation to close the pelvic ring and decrease blood loss. In certain situations--especially when associated with abdominal trauma and the need to perform laparotomies--both techniques may put the patient at risk of either pintract or deep plate infections. We describe an operative approach to percutaneously close and stabilize the pelvic ring using spinal implants as an internal fixator and report the results in a small series of patients treated with this technique during the resuscitation phase.

FINDINGS

Four patients were treated by subcutaneous placement of an internal fixator. Screw fixation was carried out by minimally invasive placement of two supra-acetabular iliac screws. Afterwards, a subcutaneous transfixation rod was inserted and attached to the screws after reduction of the pelvic ring. All patients were allowed to fully weight-bear. No losses of reduction or deep infections occurred. Fracture healing was uneventful in all cases.

CONCLUSION

Minimally invasive fixation is an alternative technique to stabilize the pelvic ring. The clinical results illustrate that this technique is able to achieve good results in terms of maintenance of reduction the pelvic ring. Also, abdominal surgeries no longer put the patient at risk of infected pins or plates.

Perforation and bacterial contamination of microscope covers in lumbar spinal decompressive surgery

OBJECTIVE

To determine the integrity of microscope covers and bacterial contamination at the end of lumbar spinal decompressive surgery.

MATERIALS AND METHODS

A prospective study of 25 consecutive lumbar spinal decompressions with the use of a surgical microscope was performed. For detection of perforations, the microscope covers were filled with water at the end of surgery and the presence of water leakage in 3 zones (objective, ocular and control panel) was examined. For detection of bacterial contamination, swabs were taken from the covers at the same locations before and after surgery.

RESULTS

Among the 25 covers, 1 (4%) perforation was observed and no association between perforation and bacterial contamination was seen; 3 (4%) of 75 smears from the 25 covers showed post-operative bacterial contamination, i.e. 2 in the ocular zone and 1 in the optical zone, without a cover perforation.

CONCLUSIONS

The incidence of microscope cover perforation was very low and was not shown to be associated with bacterial contamination. External sources of bacterial contamination seem to outweigh the problem of contamination due to failure of cover integrity.

Histological remodelling of demineralised bone matrix allograft in posterolateral fusion of the spine--an ex vivo study

Background

Demineralised bone matrix (DBM) has shown to be effective in enhancing posterior fusion of the spine. Several animal studies and clinical investigations in humans showed its successful remodelling. The use of allogenic matrix may decrease the need of autologous bone graft and therefore helps prevent corresponding donor site morbidity. Since DBM products are very expensive, the question arises, whether it is completely remodelled into new bone, and therefore truly is comparable to autologous cancellous bone graft. To our knowledge there is no report of a consecutive series of patients where ex vivo histological analysis after postero-lateral fusion of the spine was performed.

Methods

Osseous biopsies of nine consecutive patients who underwent postero-lateral fusion of the spine for trauma were obtained at the time of elective removal of the hardware. Histological samples were then analyzed on ground and thin sections stained with toluidine blue and von Kossa stainings.

Results

Time span between index operation and removal of the metal ranged between 6 and 18 month. Histological analysis showed good incorporation and overall remodelling of DBM into new bone in all patients. No foreign body reaction was visible and new bone formation progressed time dependently with DBM in situ. Four out of nine patients showed more than 50% new bone formation after one year.

Conclusion

DBM shows good overall remodelling properties in histological analysis and therefore seems to be an effective adjunct in postero-lateral fusion of the spine. Furthermore, DBM substitution increases over time.

Therapy of acute and delayed spinal infections after spinal surgery treated with negative pressure wound therapy in adult patients

We present the results of the treatment of infected primary or delayed spine wounds after spinal surgery using negative pressure wound therapy. In our institution (University Hospital Zurich, Switzerland) nine patients (three women and six men; mean age 68.6, range 43-87 years) were treated in the period between January to December 2011 for non-healing spinal wounds. The treatment consisted of repeated debridements, irrigation and temporary closure with negative pressure wound therapy system. Three patients were admitted with a spinal epidural abscess; two with osteoporotic lumbar fracture; two with pathologic vertebra fracture and spinal cord compression, and two with vertebra fracture after trauma. All nine patients have been treated with antibiotic therapy. In one case the hardware has been removed, in three patients laminectomy was performed without instrumentation, in five patients there was no need to remove the hardware. The average hospital stay was 16.6 days (range 11-30). The average follow-up was 3.8, range 0.5-14 months. The average number of negative pressure wound therapy procedures was three, with the range 1-11. Our retrospective study focuses on the clinical problems faced by the spinal surgeon, clinical outcomes after spinal surgery followed by wound infection, and negative pressure wound therapy. Moreover, we would like to emphasize the importance for the patients and their relatives to be fully informed about the increased complications of surgery and about the limitations of treatment of these wounds with negative pressure wound therapy.

Distraction test of the posterior superior iliac spine (PSIS) in the diagnosis of sacroiliac joint arthropathy

Background

The sacroiliac joint (SIJ) is a frequently underestimated cause of lower back (LBP). A simple clinical test of sufficient validity would be desirable. The aim of this study was to evaluate the diagnostic value of a new PSIS distraction test for the clinical detection of SIJ arthropathy and to compare it to several commonly used clinical tests.

Methods

Consecutive patients, where a SIJ pathology had been confirmed by an SIJ infiltration were enrolled (case group, 61 SIJs in 46 patients). Before infiltration, patients were tested for pain with PSIS distraction by a punctual force on the PSIS in medial-to-lateral direction (PSIS distraction test), pain with pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber (or Patrick’s) test. In addition, these clinical tests were applied to both SIJs of a population of individuals without history of LBP (control group, 64 SIJs in 32 patients).

Results

Within the investigated cohort, the PSIS distraction test showed a sensitivity of 100% and a specificity of 89% for SIJ pathology. The accuracy of the test was 94%, the positive predictive value (PPV) was 90% and the negative predictive value (NPV) was 100%. Pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber test were associated with a good specificity (> 90%) but a poor sensitivity (< 35%).

Conclusions

Within our population of patients with confirmed SIJ arthropathy the PSIS distraction test was found to be of high sensitivity, specificity and accuracy. In contrast, common clinical tests showed a poor sensitivity. The PSIS distraction test seems to be an easy-to-perform and clinically valuable test for SIJ arthropathy.

SPECT/CT for imaging of the spine and pelvis in clinical routine: a physician's perspective of the adoption of SPECT/CT in a clinical setting with a focus on trauma surgery

Injuries of the axial skeleton are an important field of work within orthopaedic surgery and traumatology. Most lesions following trauma may be diagnosed by means of conventional plain radiography, computed tomography or magnetic resonance imaging. However, for some aspects SPECT/ CT can be helpful even in a trauma setting. In particular, the combination of highly sensitive but nonspecific scintigraphy with nonsensitive but highly specific computed tomography makes it particularly useful in anatomically complex regions such as the pelvis and spine. From a trauma surgeon's point of view, the four main indications for nuclear medicine imaging are the detection of (occult) fractures, and the imaging of inflammatory bone and joint diseases, chronic diseases and postoperative complications such as instability of instrumentation or implants. The aim of the present review was to give an overview of the adoption of SPECT/CT in a clinical setting.

Vertebral body stenting versus kyphoplasty for the treatment of osteoporotic vertebral compression fractures: a randomized trial

BACKGROUND

In the treatment of vertebral compression fractures, vertebral body stenting with an expandable scaffold inserted before application of the bone cement was developed to impede secondary loss of vertebral height encountered in patients treated with balloon kyphoplasty. The purpose of this study was to clarify whether there are relevant differences between balloon kyphoplasty and vertebral body stenting with regard to perioperative and postoperative findings.

METHODS

In a two-armed randomized controlled trial, patients with a total of 100 fresh osteoporotic vertebral compression fractures were treated with either balloon kyphoplasty or vertebral body stenting. The primary outcome was the post-interventional change in the kyphotic angle on radiographs. The secondary outcomes were the maximum pressure of the balloon tamp during inflation, radiation exposure time, perioperative complications, and cement leakage.

RESULTS

The mean reduction (and standard deviation) of kyphosis (the kyphotic correction angle) was 4.5° ± 3.6° after balloon kyphoplasty and 4.7° ± 4.2° after vertebral body stenting (p = 0.972). The mean pressures were 24 ± 5 bar (348 ± 72 pounds per square inch [psi]) during vertebral body stenting and 16 ± 6 bar (233 ± 81 psi) during balloon kyphoplasty (p = 0.014). There were no significant differences in radiation exposure time.None of the patients underwent revision surgery, and postoperative neurologic sequelae were not observed. Cement leakage occurred at twenty-five of the 100 vertebral levels without significant differences between the two intervention arms (p = 0.230). Intraoperative material-related complications were observed at one of the fifty vertebral levels in the balloon kyphoplasty group and at nine of the fifty levels in the vertebral body stenting group.

CONCLUSIONS

No beneficial effect of vertebral body stenting over balloon kyphoplasty was found among patients with painful osteoporotic vertebral fractures with regard to kyphotic correction, cement leakage, radiation exposure time, or neurologic sequelae. Vertebral body stenting was associated with significantly higher pressures during balloon inflation and more material-related complications.

Recurrence of acute Charcot neuropathic osteoarthropathy after conservative treatment

BACKGROUND

Charcot neuropathic osteoarthropathy (CN) is a chronic, progressive-destructive process affecting the feet of patients with sensory neuropathy. Data on CN recurrence are underrepresented in the literature. The aim of the present study was to evaluate the rate of CN recurrence after its treatment and to find predisposing factors.

METHODS

Fifty-two patients (age 59 ± 11 years, 16 female) with acute CN with 57 affected feet were enrolled. Comorbidities, localization, and stage of disease at first diagnosis as well as ulcerations, need for surgery, noncompliance, and subsequent treatment (orthopedic footwear or orthotic treatment) during the course of therapy were recorded. During follow-up, the incidence of recurrence of CN was observed. Mean follow-up was 47 ± 40 months.

RESULTS

Diabetes was the most common reason for sensory neuropathy (79%). Recurrence of CN was seen in 13 feet (23%) with an interval of 27 ± 31 months (range, 3-102 months) after the end of initial immobilization. Patients with recurrence were immobilized for a shorter period of time and had a more advanced stage of CN at time of first diagnosis. Predictors of recurrence were noncompliance (odds ratio 19.7; confidence interval, 4.1-94.4; P < .001) and obesity (odds ratio 6.4; confidence interval, 1.6-25.9; P = .06).

CONCLUSIONS

Recurrence of osteoarthropathic activity is a possible complication after conservative treatment of CN. Obesity and noncompliance are strong predictors for the recurrence of CN.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Detection of posterior pelvic injuries in fractures of the pubic rami

BACKGROUND

Fractures of the pubic rami are associated with prolonged pain, bed rest and increased morbidity and mortality. Often no further diagnostic work-up is undertaken and the pubic rami fractures are classified as stable injuries. However, fractured pubic rami seem to be only part of the picture and are often associated with posterior pelvic ring injury. This retrospective study was designed to evaluate the posterior ring for undetected injury in patients diagnosed with pubic rami fractures.

METHODS

All patients (n=233) with diagnosed fractures of the pubic rami were retrospectively retrieved. All patients with a CT scan available at time of admission (n=177) were included in the study.

RESULTS

In 28.8% of the cases a fracture of the acetabulum was found additionally to the pubic rami. In cases without obvious other injury of the ap radiograph, an injury of the posterior pelvic ring was found on CT scans in 96.8% of the patients. Most lesions represented transforaminal sacral fractures, avulsion fractures of ligaments or compression fractures of the lateral mass. All patients with dorsal injuries could initially be treated conservatively, nevertheless 30% of them needed operative treatment in the course.

CONCLUSION

Nearly all cases with fractures of the pubic rami do have a lesion elsewhere within the pelvic ring. In patients with prolonged pain and immobility following 'pubic rami fractures' one should be aware that they probably represent an undiagnosed pelvic ring injury and further diagnostic work-up - sometimes even surgery - is warranted.

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels

OBJECTIVES

To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels.

METHODS

Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level.

RESULTS

Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, κ = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein.

CONCLUSIONS

Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended.

KEY POINTS

• Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

Influence of trabecular microstructure and cortical index on the complexity of proximal humeral fractures

OBJECTIVES

Poor bone quality increases the susceptibility to fractures of the proximal humerus. It is unclear whether local trabecular and cortical measures influence the severity of fracture patterns. The goal of this study was to assess parameters of trabecular and cortical bone properties and to compare these parameters with the severity of fractures and biomechanical testing.

METHODS

Twenty patients with displaced proximal humeral fractures planned for osteosynthesis were included. Fractures were classified as either 2-part fractures or complex fractures. Bone after core drilling was harvested during surgery from the humeral head in each patient. Twenty bone cores obtained from nonpaired cadaver humeral heads served as nonfractured controls. Micro-CT (μCT) was performed and bone volume/total volume (BV/TV), connectivity density (CD), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and bone mineral density (BMD) were assessed. The cortical index (CI) was determined from AP plain films. Biomechanical testing was done after μCT scanning by axially loading until failure, and ultimate strength and E modulus were recorded.

RESULTS

BV/TV, BMD and CD showed moderate to strong correlations with biomechanical testing (r = 0.45-0.76, all p < 0.05). No significant differences were detected between the 2-part and complex fracture groups and controls regarding μCT and biomechanical parameters. CI was not significantly different between the 2-part and complex fracture groups.

CONCLUSIONS

In our study population local trabecular bone structure and cortical index could not predict the severity of proximal humeral fractures in the elderly. Complex fractures do not necessarily imply lower bone quality compared to simple fractures.

Gastrocnemius muscle herniation as a rare differential diagnosis of ankle sprain: case report and review of the literature

Background

Muscle herniation of the leg is a rare clinical entity. Yet, knowing this condition is necessary to avoid misdiagnosis and delayed treatment. In the extremities, muscle herniation most commonly occurs as a result of an acquired fascial defect, often due to trauma. Different treatment options for symptomatic extremity muscle herniation in the extremities, including conservative treatment, fasciotomy and mesh repair have been described.

Case presentation

We present the case of a patient who presented with prolonged symptoms after an ankle sprain. The clinical picture showed a fascial insufficiency with muscle bulging under tension. Ultrasound and MRI imaging confirmed the diagnosis of muscle hernia of the medial gastrocnemius on the right leg. Conservative treatment did not lead to success. Therefore, the fascial defect was treated surgically by repairing the muscle herniation using a synthetic vicryl propylene patch.

Conclusions

Muscle hernias should be taken into consideration as a rare differential diagnosis whenever patients present with persisting pain or soft tissue swelling after ankle sprain. Diagnosis is mainly based on clinical aspect and physical examination, but can be confirmed by radiologic imaging techniques, including (dynamic) ultrasound and MRI. If conservative treatment fails, we recommend the closure with mesh patches for large fascial defects.

Correlation of psychomotor findings and the ability to partially weight bear

Background

Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test.

Methods

50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction.

Results

The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously.

Conclusions

The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits.

Traumatic atlantoaxial rotatory subluxation in an adolescent: a case report

Introduction

Atlantoaxial rotatory subluxation is rarely caused by trauma in adults. Usually, the treatment of choice is traction using Halo/Gardner-Wells fixation devices for up to six weeks.

Case presentation

We present the case of a 19-year-old Caucasian woman with traumatic atlantoaxial subluxation. Early reduction three hours after trauma and immobilization using only a soft collar were performed and yielded very good clinical results.

Conclusion

In the adult population, atlantoaxial subluxation is a rare condition but is severe if untreated. Early treatment implies a non-surgical approach and a good outcome. Conservative treatment is the recommended first step for this condition.

Posterior screw fixation in rotationally unstable pelvic ring injuries

OBJECTIVE

Although the stability of the pelvic ring primarily depends on the integrity of the posterior sacroiliac arch, lateral compression fractures with rotational instability are commonly treated by anterior fixation alone. The objective of the present study was to assess the outcome of patients with these fractures treated by posterior iliosacral screw fixation alone.

METHODS

Patients with rotationally unstable lateral compression fractures of the pelvic ring (Young and Burgess LC I and LC II or AO/Tile B2) treated by percutaneous iliosacral fixation alone were included. Postoperative complications, need for secondary surgery, malunion, secondary fracture displacement and the time to full-weight bearing were documented.

RESULTS

Twenty-five patients (13 female, 26 male; age: 56±20 years) were treated by percutaneous screw fixation (14 bilaterally, 11 unilaterally). Mean follow-up was 6±4 months, mean time to full weight bearing 9±3 weeks. Revision surgery was necessary in two patients (8%) due to nerve irritation; an additional anterior stabilisation was needed in two other patients (8%) due to secondary dislocation. Wound infection or motor weakness were not encountered, non-union of the posterior arch did not occur. Non-union of the pubic rami, however, occurred in two patients. The presence of malunion of the pubic rami did not affect the time to full weight bearing.

CONCLUSIONS

Percutanous iliosacral screw fixation alone is a sufficient technique for the stabilisation of rotationally unstable pelvic fractures with low rates of complications or non-unions. It allows for a minimally invasive treatment thus being a useful option in patients who do not qualify for open anterior fixation.

The calcar screw in angular stable plate fixation of proximal humeral fractures--a case study

BACKGROUND

With new minimally-invasive approaches for angular stable plate fixation of proximal humeral fractures, the need for the placement of oblique inferomedial screws ('calcar screw') has increasingly been discussed. The purpose of this study was to investigate the influence of calcar screws on secondary loss of reduction and on the occurrence of complications.

METHODS

Patients with a proximal humeral fracture who underwent angular stable plate fixation between 01/2007 and 07/2009 were included. On AP views of the shoulder, the difference in height between humeral head and the proximal end of the plate were determined postoperatively and at follow-up. Additionally, the occurrence of complications was documented. Patients with calcar screws were assigned to group C+, patients without to group C-.

RESULTS

Follow-up was possible in 60 patients (C+ 6.7 ± 5.6 M/C- 5.0 ± 2.8 M). Humeral head necrosis occurred in 6 (C+, 15.4%) and 3 (C-, 14.3%) cases. Cut-out of the proximal screws was observed in 3 (C+, 7.7%) and 1 (C-, 4.8%) cases. In each group, 1 patient showed delayed union. Implant failure or lesions of the axillary nerve were not observed. In 44 patients, true AP and Neer views were available to measure the head-plate distance. There was a significant loss of reduction in group C- (2.56 ± 2.65 mm) compared to C+ (0.77 ± 1.44 mm; p = 0.01).

CONCLUSIONS

The placement of calcar screws in the angular stable plate fixation of proximal humeral fractures is associated with less secondary loss of reduction by providing inferomedial support. An increased risk for complications could not be shown.

Matrix-associated implantation of predifferentiated mesenchymal stem cells versus articular chondrocytes: in vivo results of cartilage repair after 1 year

BACKGROUND

The use of predifferentiated mesenchymal stem cells (MSC) leads to better histological results compared with undifferentiated MSC in sheep. This raises the need for a longer term follow-up study and comparison with a clinically established method.

HYPOTHESIS

We hypothesized that chondrogenic in vitro predifferentiation of autologous MSC embedded in a collagen I hydrogel leads to better structural repair of a chronic osteochondral defect in an ovine stifle joint after 1 year. We further hypothesized that resulting histological results would be comparable with those of chondrocyte-seeded matrix-associated autologous chondrocyte transplantation (MACT).

STUDY DESIGN

Controlled laboratory study.

METHODS

Predifferentiation period of ovine MSC within collagen gel in vitro was defined by assessment of several cellular and molecular biological parameters. For the animal study, 2 osteochondral lesions (7-mm diameter) were created at the medial femoral condyles of the hind legs in 9 sheep. Implantation of MSC gels was performed 6 weeks after defect creation. Thirty-six defects were divided into 4 treatment groups: (1) chondrogenically predifferentiated MSC gels (pre-MSC gels), (2) undifferentiated MSC gels (un-MSC gels), (3) MACT gels, and (4) untreated controls (UC). Histological, immunohistochemical, and radiological evaluations followed after 12 months.

RESULTS

After 12 months in vivo, pre-MSC gels showed significantly better histological outcome compared with un-MSC gels and UC. Compared with MACT gels, the overall scores were higher for O'Driscoll and International Cartilage Repair Society (ICRS). The repair tissue of the pre-MSC group showed immunohistochemical detection of interzonal collagen type II staining. Radiological evaluation supported superior bonding of pre-MSC gels to perilesional native cartilage. Compared with previous work by our group, no degradation of the repair tissue between 6 and 12 months in vivo, particularly in pre-MSC gels, was observed.

CONCLUSION

Repair of chronic osteochondral defects with collagen hydrogels composed of chondrogenically predifferentiated MSC shows no signs of degradation after 1 year in vivo. In addition, pre-MSC gels lead to partially superior histological results compared with articular chondrocytes.

CLINICAL RELEVANCE

The results suggest an encouraging method for future treatment of focal osteochondral defects without donor site morbidity by harvesting articular chondrocytes.