Mechanical outcomes of the TFNA, InterTAN and IMHS intramedullary nailing systems for the fixation of proximal femur fractures

INTRODUCTION

Hip fractures have become a major public health priority due to their increasing incidence. Intramedullary (IM) nailing has gained popularity as a surgical technique for managing these fractures. However, comparative studies with extramedullary devices indicate potentially increased mechanical complications associated with IM nailing. Specifically, there have been recent reports of early implant fracture associated with the TFNA system. This study compares the rate of mechanical complications between 3 implants. Secondarily, we analysed the factors associated with implant fracture and all other mechanical complications.

METHODS

This retrospective study included 803 IM nails performed between 2008-2021 for the fixation of proximal femur fractures at a level 1 trauma centre. We recorded patient demographics, AO fracture classification, implant specification and intra-operative parameters such as tip-apex distance, Cleveland index, reduction quality, presence of medial calcar integrity, neck-shaft angle. The outcomes analysed included implant fracture, lag screw cut-out, >10 mm backing out, autodynamisation, periprosthetic fracture, non-union at 6 months and time to revision surgery.

RESULTS

The overall implant fracture rate was 3.1 % (25/803), with no statistically significant difference between the three devices (p = 0.51). The TFNA group included 183 patients with a median follow-up of 1.6 years. The TFNA fracture rate was 2.2 % (4/183) which occurred at 207 +/- 16.66 days post-operatively. The rate of all mechanical complications was 4.9 % in the TFNA group, 12.9 % in the InterTAN group and 17 % in the IMHS group. Non-union (p < 0.001) and increasing lag screw length (p < 0.02) were identified as risk factors for implant fracture and other mechanical complications. The reverse oblique fracture pattern (AO 31 A3.1) was associated with mechanical complications only (p < 0.01). The cumulative survival rates without revision for the TFNA, InterTAN, IMHS groups were 97.8 %, 95.5 % and 87.9 % respectively at 2.5 years.

DISCUSSION

The rates of implant fracture were comparable between the three nailing systems. The TFNA provides effective fixation for proximal femur fractures using a traditional screw without cement augmentation. The TFNA was associated with an overall reduction in mechanical complications compared to the InterTAN and IMHS. Previously reported mechanical complications associated with IM Nails may relate to older device designs.

Pilot study of micromotion nailing for mechanical stimulation of tibial fracture healing

Aims

The study objective was to prospectively assess clinical outcomes for a pilot cohort of tibial shaft fractures treated with a new tibial nailing system that produces controlled axial interfragmentary micromotion. The hypothesis was that axial micromotion enhances fracture healing compared to static interlocking.

Methods

Patients were treated in a single level I trauma centre over a 2.5-year period. Group allocation was not randomized; both the micromotion nail and standard-of-care static locking nails (control group) were commercially available and selected at the discretion of the treating surgeons. Injury risk levels were quantified using the Nonunion Risk Determination (NURD) score. Radiological healing was assessed until 24 weeks or clinical union. Low-dose CT scans were acquired at 12 weeks and virtual mechanical testing was performed to objectively assess structural bone healing.

Results

A total of 37 micromotion patients and 46 control patients were evaluated. There were no significant differences between groups in terms of age, sex, the proportion of open fractures, or NURD score. There were no nonunions (0%) in the micromotion group versus five (11%) in the control group. The proportion of fractures united was significantly higher in the micromotion group compared to control at 12 weeks (54% vs 30% united; p = 0.043), 18 weeks (81% vs 59%; p = 0.034), and 24 weeks (97% vs 74%; p = 0.005). Structural bone healing scores as assessed by CT scans tended to be higher with micromotion compared to control and this difference reached significance in patients who had biological comorbidities such as smoking.

Conclusion

In this pilot study, micromotion fixation was associated with improved healing compared to standard tibial nailing. Further prospective clinical studies will be needed to assess the strength and generalizability of any potential benefits of micromotion fixation.

Cite this article: Bone Jt Open 2021;2(10):825–833.

The decline of hip fracture incidence rates over a 10-year period: A single centre experience

AIMS

Accurate epidemiological hip fracture data is essential for healthcare planning and targeted prevention strategies. Limited reports of hip fracture incidence rates in the Republic of Ireland (ROI) exist. The aim is to calculate the current age- and gender-specific incidence of hip fractures in a level 1 Trauma Centre in the ROI, and the difference in these rates over a 10 year period.

MATERIALS AND METHODS

This was a retrospective, population-based, observational study. The local Hospital In-Patient Enquiry (HIPE) database was used to generate data for analysis; capturing all patients admitted for hip fracture in three time periods over 10 years. Patients < 55 years old, pathological fractures, and periprosthetic fractures were excluded. Age- and gender-specific incidence rate was calculated using HIPE and national census data.

RESULTS

Absolute number of hip fractures rose by 8.5% between 2008/09 (n = 800) and 2018/19 (n = 868) time periods. Cervical hip fractures dominated in all 3 time periods. The average age of patients remained at 80 years but length of stay for patients was reduced by 16% 5 years later and by 21% 10 years later from the initial study point. Both the entire and susceptible (> 55 years) population numbers increased by 13% and 30%, respectively, yet overall hip fracture incidence rate declined 10 years on. Hip fracture incidence rate in the entire population fell by 3.23 per 100,000 population, and by 65.11 per 100,000 population in the susceptible population. The majority of both male and female age groups exhibited declining annual incidence rates over the 10 year study period.

CONCLUSION

Results are consistent with the global experience of declining overall incidence rate of hip fractures, despite rising susceptible population numbers. This report adds to the sparse hip fracture incidence data available in the ROI which can be applied in future healthcare planning strategies.

Trabecular Metal Augments for Severe Acetabular Defects in Revision Hip Arthroplasty: A Long-Term Follow-Up

BACKGROUND

Paprosky type IIIa and IIIb acetabular defects remain technically challenging during revision hip arthroplasty. Numerous surgical options exist to counter extensive acetabular bone loss with high postoperative complication and revision rates reported. Our aim was to report comprehensive long-term outcomes of our experience with Trabecular Metal (TM) augments for these difficult cases.

METHODS

38 patients underwent revision total hip arthroplasty at our institution from 2009 to 2014 where a TM augment was used for acetabular deficiency. Prospective radiographic and Patient-Reported Outcome Measures were recorded and analyzed to a mean of 7.3 years (range: 5.4 to 10.8).

RESULTS

No patient was excluded or lost to follow-up. Complications included 3 intraoperative fractures, 1 early infection requiring washout with implant retention, 1 early revision due to allograft resorption, and 6 patients who required late repeat revision surgery: 3 for late infection, 2 for aseptic loosening with augment fracture or dislocation, and 1 for recurrent dislocation. The estimated mean implant survivorship was 8.99 years. 93.5% of augments remaining were well osseointegrated while 97% of the acetabular shells were osseointegrated. Hip center of rotation was restored by a mean of 14 mm inferiorly without significant medialization. Short Form-12 (SF-12) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were significantly reduced postoperatively to a level comparable to the average individual.

CONCLUSION

This long-term study details our experience of TM augments for the most severe acetabular defects. For such cases, no excellent surgical solution exists; in comparison to alternative methods, we advocate that this technique is reasonably safe and effective.

Nontraumatic Tibial Polyethylene Insert Cone Fracture in Rotating-Platform Total Knee Arthroplasty

We report a case of a fracture through the polyethylene (PE) insert cone in a rotating-platform (RP) primary total knee arthroplasty (TKA) implant. This is the first reported case of cone fracture with this particular implant. This case highlights a 65-year-old female presenting with a 4-month history of knee pain and symptoms of instability 10 years after primary RP TKA. At the time of revision surgery, the PE insert cone was found to be fractured 10 mm from the inferior surface of the PE liner. Analysis suggests that the cone fracture occurred by fatigue failure which caused loosening of the tibial tray. Clinicians should be aware that this is a potential cause of failure with an RP TKA in the setting of symptoms including instability and pain.

Patellar stabilization surgeries in cases of recurrent patellar instability: a retrospective clinical and radiological audit

BACKGROUND

Patellar instability is a disabling condition that limits the functional ability and physical aspirations of patients. There are multiple anatomical structures which stabilize the patella and surgical treatment is tailored to repair the underlying aetiology.

AIMS

To evaluate the clinical and radiological outcome of patellar stabilization procedures in patients with recurrent patellar instability.

METHODS

We analysed 34 patients (36 knees) (mean age, 26.6) with recurrent patellar instability who underwent patellar stabilization surgery from June 2009 to September 2014. Type of procedure was dependent on the concomitant aetiological factors; tibial tuberosity osteotomy (61.76%), medial patellofemoral ligament reconstruction (67.64%), lateral release (5.88%) and trochleoplasty (2.94%). Mean follow-up was 3 years (range 9 months-6 years).

RESULTS

At follow-up, 77% of patients were satisfied with the overall outcome of the procedure. The mean IKDC was 66.7, Lysholm 74.9. Mean patellar height decreased significantly (P < .05) to anatomical values. Pre-operatively, the mean tibial tuberosity-trochlear groove distance was 14.66 mm (55.6% at borderline/abnormal level) and 81% showed evidence of trochlear dysplasia. Complications were found in 3 patients (8.33%), 2 of which had further episodes of instability.

CONCLUSIONS

Patellar stabilization surgery is an effective method of treating patellar instability, resulting in stability of the knee in 94.4%. Despite this, patient dissatisfaction rates are quite high suggesting that this patient group, whilst mostly stable, remains significantly symptomatic from their knee. These positive results which are reflected in the recent literature represent a strong case for consideration of primary surgical stabilization in cases of patellar instability.

Polyethylene spinout in the Attune® Cruciate-Retaining Rotating-Platform (CR RP) total knee arthroplasty performed with a cruciate-sacrificing and measured-resection technique

INTRODUCTION

Polyethylene (PE) spinout is a known but uncommon complication when using a mobile-bearing (MB) total knee arthroplasty (TKA) design. Sacrificing the posterior cruciate ligament (PCL) is within the manufacturer's recommendations for the Attune® Cruciate-Retaining Rotating-Platform (CR RP) knee design.

AIM

To discuss the potential aetiology and prevention of spinout in the Attune® CR RP knee.

METHODS

We used a retrospective radiological review from two centres reporting a higher rate of spinout in the Attune® CR RP knee using a cruciate-sacrificing and measured-resection technique when compared to a gap-balancing technique. Three hundred and thirty-two patients were evaluated over a 3-year period.

RESULTS

There were 8 out of 279 (2.86%) cases of spinout in our first cohort of patients using a measured-resection technique. There were 0 out of 53 cases of spinout in our second cohort of patients where a gap-balancing technique was used. One spinout was reduced closed, the other seven were initially revised to a thicker RP insert of the same design. Of these seven, three underwent a further revision TKA and one patient required a knee fusion/arthrodesis.

CONCLUSIONS

This study reports a higher incidence of PE spinout in the Attune® CR RP TKA when a measured-resection technique in combination with PCL resection is performed. We recommend a gap-balancing technique with conservative soft-tissue release if the surgeon is planning to sacrifice the PCL in the Attune® CR RP.

Follow-up study on transphyseal ACL reconstruction in Irish adolescents with no cases of leg length discrepancy or angular deformity

BACKGROUND

The rate of ACL injury in adolescents has been rising in recent years. Surgical options include transphyseal and physeal-sparing ACL reconstruction.

AIMS

In this study, we performed a transphyseal ACL reconstruction and followed up patients to assess functional outcomes and to assess for growth disturbance.

METHOD

There were 22 patients seen at follow-up between the age of 12 and 16. Skeletal age assessment was performed using an MRI atlas with an average skeletal age of 14.7 (range 12-16). The mean follow-up time was 36 months (range 14-63 months). Clinical examination was performed to assess for leg length discrepancy, and leg length radiographs were used to assess for angular deformity. Patients' post-surgery functionality was assessed with the IKDC score and the Tegner Lysholm score.

RESULTS

The mean IKDC and Lysholm scores at follow-up were found to be 91 and 94, respectively. The median Tegner score prior to injury was 8.5 and postoperatively was 7.5. There were no cases of leg length discrepancy found on clinical examination, and there were no cases of significant angular deformity. Four patients ruptured again and went on to have repeat ACL reconstruction.

CONCLUSIONS

Midterm results at an average follow-up of 3 years after the surgery showed good functional outcomes using the transphyseal ACL reconstruction technique with good return to activity. There were no cases of leg length discrepancy or angular deformity. Transphyseal ACL reconstruction is a viable method of treatment for adolescent ACL tears.

Virtual Mechanical Testing Based on Low-Dose Computed Tomography Scans for Tibial Fracture: A Pilot Study of Prediction of Time to Union and Comparison with Subjective Outcomes Scoring

BACKGROUND

Quantitative outcomes assessment remains a persistent challenge in orthopaedic trauma. Although patient-reported outcome measures (PROMs) and radiographic assessments such as Radiographic Union Scale for Tibial Fractures (RUST) scores are frequently used, very little evidence has been presented to support their validity for measuring structural bone formation or biomechanical integrity.

METHODS

In this pilot study, a sequential cohort of patients with a tibial shaft fracture were prospectively recruited for observation following standard reamed intramedullary nailing in a level-I trauma center. Follow-up at 6, 12, 18, and 24 weeks included radiographs and completion of PROMs (EuroQol 5-Dimension [EQ-5D] and pain scores). Low-dose computed tomography (CT) scans were also performed at 12 weeks. Scans were reconstructed in 3 dimensions (3D) and subjected to virtual mechanical testing via the finite element method to assess torsional rigidity in the fractured limb relative to that in the intact bone.

RESULTS

Patients reported progressive longitudinal improvement in mobility, self-care, activity, and health over time, but the PROMs were not correlated with structural bone healing. RUST scoring showed moderate intrarater agreement (intraclass coefficient [ICC] = 0.727), but the scores at 12 weeks were not correlated with the time to union (R = 0.104, p = 0.193) and were only moderately correlated with callus structural integrity (R = 0.347, p = 0.010). In contrast, patient-specific virtual torsional rigidity (VTR) was significantly correlated with the time to union (R = 0.383, p = 0.005) and clearly differentiated 1 case of delayed union (VTR = 10%, union at 36 weeks) from the cases in the normally healing cohort (VTR > 60%; median union time, 19 weeks) on the basis of CT data alone.

CONCLUSIONS

PROMs provide insight into the natural history of the patient experience after tibial fracture but have limited utility as a measure of structural bone healing. RUST scoring, although reproducible, may not reliably predict time to union. In contrast, virtual mechanical testing with low-dose CT scans provides a quantitative and objective structural callus assessment that reliably predicts time to union and may enable early diagnosis of compromised healing.

LEVEL OF EVIDENCE

Therapeutic Level IV. Please see Instructions for Authors for a complete description of levels of evidence.

Arthroplasty and global research output: A bibliometric analysis

Introduction

Peer-reviewed research helps to advance many aspects of medical and surgical practice. This paper determines the main contributors tos joint arthroplasty research in terms of quantity and quality.

Methods

A search of the Web of Science™ platform was conducted to identify arthroplasty articles published between 2001 and 2016. The number of articles and citations per article were analysed to assess the quantity and quality of research from individual countries. Results were standardised according to the country's populations and Gross Domestic Product (GDP).

Results

In total, 43,470 arthroplasty articles were published worldwide from January 2001 through December 2016. There was a 4.5-fold increase in global output during this time period. Twenty-two countries contributed at least 1% to the total number of publications. The United States of America published the most articles (35.40%), followed by England (10.31%) and Germany (10.03%). The USA had the highest absolute number of citations (50,777). Denmark had the highest average citation per item (8.76). When number of articles was normalized to population, Switzerland ranked the highest. When adjusted by GDP, Scotland ranked highest. When standardised according to GDP per capita, the People's Republic of China rated highest. The Journal of Arthroplasty produced the highest number of publications related to arthroplasty with 10.9% of total volume.

Conclusion

There has been a substantial increase in worldwide publications relating to arthroplasty. The USA has produced the largest volume whilst Denmark has produced the highest quality publications. When output was normalized according to population and GDP, Switzerland and Scotland ranked highest.

Acetabular Revision Using Trabecular Metal Augments for Paprosky Type 3 Defects

BACKGROUND

Trabecular Metal (TM) augments are one option when reconstructing bone loss during acetabular side revision surgery.

METHODS

We studied 38 consecutive patients with Paprosky type 3 defects that were revised using a TM shell and one or more augments over a 6-year period. There were 29 Paprosky type 3A defects and 9 Paprosky type 3B defects. The mean age of the patients at the time of surgery was 68.2 years (range 48-84). The mean length of follow-up was 36 months (range 18-74).

RESULTS

The mean preoperative short form 12 health survey improved from 27.7 before operation to 30.1 at the time of final follow-up (P = .001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score improved from 53 preoperatively to a mean of 78.8 at final follow-up (P < .0001). There was evidence of radiographic loosening in 7 of the cup-augment constructs. One patient developed a deep infection requiring re-revision. Two patients required revision for aseptic loosening.

CONCLUSION

The use of TM in complex acetabular reconstruction is associated with good outcome in the short to medium term.

Role of the fibula in the stability of diaphyseal tibial fractures fixed by intramedullary nailing

BACKGROUND

For tibial fractures, the decision to fix a concomitant fibular fracture is undertaken on a case-by-case basis. To aid in this clinical decision-making process, we investigated whether loss of integrity of the fibula significantly destabilises midshaft tibial fractures, whether fixation of the fibula restores stability to the tibia, and whether removal of the fibula and interosseous membrane for expediency in biomechanical testing significantly influences tibial interfragmentary mechanics.

METHODS

Tibia/fibula pairs were harvested from six cadaveric donors with the interosseous membrane intact. A tibial osteotomy fracture was fixed by reamed intramedullary (IM) nailing. Axial, torsion, bending, and shear tests were completed for four models of fibular involvement: intact fibula, osteotomy fracture, fibular plating, and resected fibula and interosseous membrane.

FINDINGS

Overall construct stiffness decreased slightly with fibular osteotomy compared to intact bone, but this change was not statistically significant. Under low loads, the influence of the fibula on construct stability was only statistically significant in torsion (large effect size). Fibular plating stiffened the construct slightly, but this change was not statistically significant compared to the fibular osteotomy case. Complete resection of the fibula and interosseous membrane significantly decreased construct torsional stiffness only (large effect size).

INTERPRETATION

These results suggest that fixation of the fibula may not contribute significantly to the stability of diaphyseal tibial fractures and should not be undertaken unless otherwise clinically indicated. For testing purposes, load-sharing through the interosseous membrane contributes significantly to overall construct mechanics, especially in torsion, and we recommend preservation of these structures when possible.

Automated measurement of fracture callus in radiographs using portable software

The development of software applications that assist the radiographic evaluation of fracture healing could advance clinical diagnosis and expedite the identification of effective treatment strategies. A radiographic feature regularly used as an outcome measure for basic and clinical fracture healing research is new bone growth, or fracture callus. In this study, we developed OrthoRead, a portable software application that uses image-processing algorithms to detect and measure fracture callus in plain radiographs. OrthoRead utilizes an optimal boundary tracking algorithm to semi-automatically segment the cortical surface, and a novel iterative thresholding selection algorithm to then automatically segment the fracture callus. The software was validated in three steps. First, algorithm accuracy and sensitivity were analyzed using surrogate models with known callus size. Second, the callus area of distal femur fractures measured using OrthoRead was compared to callus area manually outlined by orthopaedic surgeons. Third, the callus area of ovine tibial fractures was measured using OrthoRead and compared to callus volume measured from micro-CT. The software had less than a 5% error in measuring surrogate callus, and was insensitive to changes in image resolution, image rotation, and the size of the analyzed region of interest. Strong positive correlations existed between OrthoRead and clinicians (R(2)  = 0.98), and between 2D callus area and 3D callus volume (R(2)  = 0.70). The average run time for OrthoRead was 3 s when using a 2.7 GHz processor. By being accurate, fast, and robust, OrthoRead can support prospective and retrospective clinical studies investigating implant efficacy, and can assist research on fracture healing mechanobiology. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1224-1233, 2016.

Radiographic findings after pubic symphysiotomy: mean time to follow-up of 41.6 years

BACKGROUND

Pubic symphysiotomy is a rarely performed procedure in which the pubic symphysis is divided to facilitate vaginal delivery in cases of obstructed labor. Recently, many obstetricians have shown renewed interest in this procedure. The purpose of this paper is to report the long-term radiographic findings for patients who had undergone pubic symphysiotomy compared with the radiographic appearance of a group of age-matched and parity-matched controls.

METHODS

This was a retrospective case-control study. Twenty-five women who had previously undergone pubic symphysiotomy for childbirth were compared with twenty-five age-matched and parity-matched controls. The radiographic parameters recorded included pubic symphysis width, pubic symphysis translation, grade of sacroiliac joint osteoarthritis, and presence of parasymphyseal degeneration.

RESULTS

The mean time to follow-up after symphysiotomy was 41.6 years (range, twenty-two to fifty-five years). The symphysiotomy group had a significantly higher proportion of patients (80%) with high-grade sacroiliac joint osteoarthritis (Grade 3 or 4 according to the Kellgren and Lawrence osteoarthritis scoring system) than the control group (16%) (p < 0.001). Within the symphysiotomy group, patients with high-grade sacroiliac joint osteoarthritis tended to be older, have a longer time to follow-up, and have a larger pubic symphysis width. The control group had a higher prevalence of parasymphyseal degeneration than did the symphysiotomy group (p = 0.011).

CONCLUSIONS

Late-onset sacroiliac joint osteoarthritis secondary to pelvic instability was a major finding in this study and, to our knowledge, has not been discussed previously in the literature regarding pubic symphysiotomy.

Inflammatory pseudotumor causing deep vein thrombosis after metal-on-metal hip resurfacing arthroplasty

Metal-on-metal hip resurfacings have recently been associated with a variety of complications resulting from adverse reaction to metal debris. We report a case of extensive soft tissue necrosis associated with a huge pelvic mass causing extensive deep vein thrombosis of the lower limb secondary to mechanical compression of the iliac vein. This is a rare and unusual cause of deep vein thrombosis after metal-on-metal hip resurfacing arthroplasty.

Comparison of serum Dkk1 (Dickkopf-1) and bone mineral density in patients on bisphosphonate treatment vs no treatment

Complex pathways affect bone metabolism at the cellular level, and a balance between osteoblast and osteoclast activity is critical to bone remodeling. One of the major pathways affecting bone metabolism is Wnt/β-catenin signaling, and its disturbances lead to a wide range of bone abnormalities. An important antagonist of this pathway is Dickkopf-1 (Dkk1). Higher Dkk1 levels have been associated with increased bone loss due to inhibition of Wnt pathway. Currently, bisphosphonates are the most commonly used agents to treat primary osteoporotic patients. This study demonstrates the effect of bisphosphonates on Dkk1 levels and its correlation with bone mineral density (BMD). Eighty patients with low BMD were recruited and divided into 2 groups of 40 each (bisphosphonate treatment group and control group). The mean Dkk1 level in the treatment group was significantly reduced to 2358.18 vs 3749.80 pg/mL in the control group (p<0.001). Pearson correlation coefficient showed negative correlation between Dkk1 and BMD at lumbar spine (r=-0.55) and femoral neck in the control group; however, no such correlation was found in the treatment group (r=-0.05). Hence, bisphosphonate therapy leads to reduction in Dkk1 levels, but it does not correlate with BMD in such patients.

Preoperative estimation of tibial nail length--because size does matter

INTRODUCTION

Selecting the correct tibial nail length is essential for satisfactory outcomes. Nails that are inserted and are found to be of inappropriate length should be removed. Accurate preoperative nail estimation has the potential to reduce intra-operative errors, operative time and radiation exposure.

METHODS

We compared the most commonly used radiological, anthropometric and intra-operative techniques to determine ideal nail lengths for 16 paired cadaveric tibiae. Five different anthropometric measurements were taken from each intact cadaver including: knee joint line to ankle joint line distance (JJD), medial knee joint line to medial malleolus distance (MMD), tibial tuberosity to medial malleolus distance (TMD), olecranon to 5th metacarpal head distance (OMD) and body height (BHR). Each tibia also underwent antero-posterior (AP) and lateral scanograms. Computerised tomography was used to determine the ideal nail length for each tibia. Each anthropometric and radiological measurement was recorded by two orthopaedic surgeons independently. An expert tibial nail was then inserted after nail length estimation was performed using a guidewire technique and an intra-operative radiographic ruler.

RESULTS

The AP scanogram was found to be 100% accurate in selecting ideal nail length. The lateral scanogram was also found to be reasonably accurate but in 19% (3/16) of cases it led to a nail being too long. The intra-operative radiographic ruler was found to give a good indication of the ideal nail size, as did the guidewire technique, with only 6% (1/16) of cases producing an incorrect nail size. In general, the anatomical measurements gave a poor indication of ideal nail size compared with the other techniques. The following accuracies were noted: JJD 56%, MMD 50%, TMD 38%, BHR 13% and OMD 56%.

CONCLUSIONS

We found that radiological methods such as using an AP radiograph with known magnification and intra-operative radiographic ruler were able to predict nail length very accurately and we suggest that these measurements should be performed routinely. The guidewire technique was also effective but we recommend that it not be used in isolation as errors can occur. We found that anatomical measurements are not accurate for predicting tibial nail length.

A novel intramedullary nail for micromotion stimulation of tibial fractures

BACKGROUND

Animal studies and clinical trials have suggested that early application of controlled axial micromotion can accelerate healing of long bone fractures compared to rigid fixation. However, experimental investigations of micromotion constructs have been limited to external fixators, which have a higher incidence of complications than intramedullary nails. The purpose of this study was to assess whether a novel intramedullary nail design can generate stimulatory micromotion under minimal weight-bearing loads typical of the early healing period.

METHODS

Eight cadaver tibiae were reamed, osteotomised, and implanted with commercially-available IM nails fitted with a custom insert that allowed 1mm of axial micromotion after proximal/distal interlocking. Specimens were mounted in a materials testing machine and subjected to cyclic axial loading while interfragmentary motion was measured using an extensometer. Implants were also tested in standard statically-locked mode.

FINDINGS

The average force required to cause distraction of the fracture gap in micromotion mode was 37.0 (SD 21.7) N. The mean construct stiffness was 1046.8 (SD 193.6) N/mm in static locking mode and 512.4 (SD 99.6) N/mm in micromotion mode (significantly different, P<0.001).

INTERPRETATION

These results support the development of a micromotion-enabled IM nail because the forces required to cause interfragmentary movements are very low, less than the weight of the hanging shank and foot. In contrast to rigid-fixation nails, which require significant weight-bearing to induce interfragmentary motion, the micromotion-enabled nail may allow movement in non-weight-bearing patients during the early healing period when the benefits of mechanical stimulation are most critical.

Cost analysis of a falls-prevention program in an orthopaedic setting

BACKGROUND

Falls by orthopaedic patients may lead to negative outcomes such as injury, prolonged hospitalization, delayed rehabilitation, and increased costs.

QUESTIONS/PURPOSES

We examined the impact of a multidisciplinary Falls-prevention Program (FPP) on the incidence of inpatient falls and fall-related injuries in an orthopaedic hospital during a 6-year period.

METHODS

Patient data and fall incident report data were reviewed to identify risk factors associated with falls and fall-related injuries. A cost analysis was performed to calculate costs incurred as a result of falls.

RESULTS

A total of 415 falls occurred during a 5-year period preintervention. The fall rate preintervention was significantly higher than the fall rate postintervention (3.49 versus 2.68 per 1000 bed days). Eighty-five falls occurred in the 12 months preintervention. A total of 15.29% (13 of 85) of falls resulted in minor injuries, and 9.42% (eight of 85) resulted in major injuries. The total cost incurred during this period as a result of falls was $117,754.12. Of this, 95.5% resulted from patients who sustained a hip fracture (n = 4). The total cost of implementing the FPP was $15,694.46. In the 12 months postintervention, 52 falls occurred. Twenty-five percent (13 of 52) of falls resulted in minor injuries, and 5.76% (two of 52) resulted in major injuries (no hip fractures). The total costs accrued during this period as a result of falls was $811.70.

CONCLUSIONS

After implementation of a FPP, there were significant decreases in fall incidence, fall-related morbidity, and consequent costs.

LEVEL OF EVIDENCE

Level III, economic and decision analyses. See the Guidelines for Authors for a complete description of levels of evidence.

Septic arthritis of the ankle due to Salmonella enteritidis

Salmonella septic arthritis in healthy, immunocompetent patients is extremely rare. We present the case of a 70-year-old man who presented with a one-day history of painful swelling of his ankle from which was aspirated pus which subsequently grew Salmonella enteritidis. There was no history of trauma or symptoms consistent with Salmonella enterocolitis. Our patient recovered fully after two weeks on intravenous ceftriaxone and six weeks on oral ciprofloxacin. Salmonella is a notifiable disease in the European Union and the United States of America, and is associated with outbreaks as a result of food contamination. The nature of Salmonella arthritis and its appropriate management are outlined.

Infection or metal hypersensitivity? The diagnostic challenge of failure in metal-on-metal bearings

The use of second generation metal-on-metal hip articulations has gained favour in the past few years. A hypersensitivity reaction to the metal-on-metal bearing, although rare, is a reported complication and is a novel mode of failure of these implants. Differentiating failure secondary to infection from failure secondary to metal hypersensitivity represents a significant diagnostic challenge. A retrospective review of all cases of hip arthroplasty using metal-on-metal bearings over a 5-year period at a tertiary referral centre identified 3 cases of failure secondary to metal hypersensitivity. Clinical presentation, serological markers, radiological imaging and histological analysis of all cases identified were evaluated. Histological analysis of periprosthetic tissue in all 3 cases identified characteristic features such as perivascular lymphocytic aggregates and chronic inflammation consistent with aseptic lymphocytic vasculitis-associated lesions (ALVAL). This study highlights that failure secondary to metal hypersensitivity must be considered in patients presenting with the reappearance of persistent pain, marked joint effusion, and the development of early osteolysis in the absence of infection.

Popliteal angle as an indicator for successful closed reduction of developmental dysplasia of the hip

PURPOSE

To evaluate the use of the popliteal angle as an indicator for successful closed reduction of developmental dysplasia of the hip (DDH) in children with delayed presentation.

METHODS

29 patients aged 6 to 18 months underwent successful closed reduction for unilateral DDH under general anaesthesia. Using a graduated goniometer, the popliteal angle was measured with the hip abducted within the safe zone (to avoid redislocation and injury to the femoral capital epiphysis) before and after reduction and after 6 weeks of spica casting.

RESULTS

The mean popliteal angles before and after reduction and after 6 weeks of spica casting were 5.1, 37.5, and 17.9 degrees, respectively (p<0.0001, paired t test). Because of discomfort, the spica casts were altered in 3 patients (2 at week 1 and one at week 3).

CONCLUSION

Reduction of the hip in DDH results in an increased popliteal angle of >20 degree. This may be used to indicate the diagnosis and safe closed reduction.

Recurrent spontaneous hip dislocation in a patient with neurofibromatosis type 1: a case report

INTRODUCTION

Neurofibromatosis type-1 is a common genetic disorder which often affects the skeleton. Skeletal manifestations of neurofibromatosis type-1 include scoliosis, congenital pseudarthrosis of the tibia and intraosseous cystic lesions. Dislocation of the hip associated with neurofibromatosis type-1 is a rare occurrence and is underreported in the literature.

CASE PRESENTATION

We report a case of hip dislocation resulting from an intra-articular neurofibroma in an 18-year-old Caucasian woman following minor trauma. This was originally suggested by the abnormalities on early radiographs of her pelvis and later confirmed with computed tomography and magnetic resonance imaging. Treatment was successful with skeletal traction for six weeks with no further hip dislocations at a 12-year follow-up.

CONCLUSION

This case illustrates the radiological features of this rare complication of neurofibromatosis type-1 using the modalities of plain radiograph, magnetic resonance imaging and computed tomography reconstruction. The radiological images give a clear insight into the mechanism by which neurofibromatosis type-1 leads to hip dislocation. It also demonstrates one treatment option with excellent results on long-term follow-up.

A review of the use of common antiplatelet agents in orthopaedic practice

Antiplatelet agents are widely prescribed for the primary and secondary prevention of cardiovascular events. A common clinical problem facing orthopaedic and trauma surgeons is how to manage patients receiving these agents who require surgery, either electively or following trauma. The dilemma is to balance the risk of increased blood loss if the antiplatelet agents are continued peri-operatively against the risk of coronary artery/stent thrombosis and/or other vascular event if the drugs are stopped. The traditional approach of stopping these medications up to two weeks before surgery appears to pose significant danger to patients and may require review. This paper covers the important aspects regarding the two most commonly prescribed antiplatelet agents, aspirin and clopidogrel.

Comparison of acetabular reamings during hip resurfacing versus uncemented total hip arthroplasty

PURPOSE

To compare the quantity of bone removed from the acetabulum during resurfacing hip arthroplasty versus uncemented total hip arthroplasty (THA).

METHODS

62 consecutive patients with osteoarthritis of the hip were prospectively studied. 24 men and 7 women aged 40 to 86 (mean, 59) years underwent Birmingham hip resurfacing. 13 men and 18 women aged 34 to 88 (mean, 61) years underwent uncemented THA using the trident acetabular cup. Obese elderly women at risk of femoral neck fracture and patients with large subchondral pseudocysts or a history of avascular necrosis of the femoral head were assigned to uncemented THA. Acetabular reamings were collected; marginal osteophytes were not included. The reamings were dehydrated, defatted, and weighed.

RESULTS

The mean weight of acetabular reamings was not significantly different between patients undergoing hip resurfacing and uncemented THA (p=0.57).

CONCLUSION

In hip resurfacing, the use of an appropriately small femoral component avoids oversizing the acetabular component and removal of excessive bone stock.

Evaluation of Hylamer-zirconia hip arthroplasty in patients less than 50 years of age

The purpose of this prospective study was to determine the clinical outcomes of patients who had total hip arthroplasties with a zirconia (Zr) - Hylamer pairing. Fifty-eight consecutive cemented total hip arthroplasties with a Hylamer cup and 22.25 mm Zr head were examined for component wear and failure. The SF-36 and Mayo hip score were used to evaluate patient outcome. Regression and Kaplan Meier survival analyses were used to determine outcome. The mean Mayo postoperative score was 94 points. The median post-operative SF-36 score was 84 points. The mean rate of wear was 0.097 +/- 0.02 mm/year, with no evidence of loosening or significant osteolysis at a minimum follow-up of 5 years. Kaplan-Meier survival analysis was 98% at 3-year follow-up and 94% at 5-year follow-up. This study has confounded previous reports relating to Zirconia-Hylamer counter-surface components.

Anti-platelet agents and surgical delay in elderly patients with hip fractures

PURPOSE

To assess the risk of surgical delay in elderly hip fracture patients on anti-platelet agents.

METHODS

Records of 180 patients aged over 65 years with either an intertrochanteric or femoral neck fracture were reviewed. The clopidogrel group included 10 patients on clopidogrel alone and 11 others on clopidogrel and aspirin, whereas the control group included 69 on aspirin alone and the remaining 90 not on any anti-coagulants. The 2 groups were compared with regard to time to surgery, preoperative American Society of Anesthesiologists (ASA) score, pre- and post-operative haemoglobin levels, in-patient complication rates, duration of hospital stay, and 30-day mortality.

RESULTS

In the clopidogrel and control groups respectively, the mean times to surgery were 7.2 and 2.1 days (p=0.03, t-test), the mean preoperative ASA scores were 3.35 and 2.8 (p=0.29, t-test), the mean preoperative haemoglobin levels were 119 and 115 g/l (p=0.5, t-test), the mean postoperative haemoglobin levels were 98 and 96 g/l (p=0.68, t-test), the mean durations of hospital stay were 7.4 and 3.1 days (p=0.02, t-test). The 30-day mortalities were 6/21 (29%) and 6/159 (4%) [p=0.0003, Fisher's exact test].

CONCLUSION

Surgical delay in elderly patients on anti-platelet agents with hip fracture was associated with higher mortality. Despite the risk of increased blood loss, we suggest early surgery be carried out by an experienced surgeon to expedite the operating time. Pooled platelets should be given intravenously one to 2 hours preoperatively.

Dual energy X-ray absorptiometry analysis of peri-prosthetic stress shielding in the Birmingham resurfacing hip replacement

INTRODUCTION

Numerous reports in the literature refer to the femoral neck fracture rate in hip resurfacing. The aim of this study was to determine the bone mineral density and evidence of stress shielding around the femoral component of the Birmingham resurfacing prosthesis.

MATERIAL AND METHODS

Twenty-eight patients with primary unilateral osteoarthritis had a Birmingham resurfacing prosthesis. DEXA analysis of the proximal femur and femoral neck was performed and compared with the opposite unaffected side.

RESULTS

Total periprosthetic bone mineral density was 0.49% greater than the control, but this did not achieve statistical significance. Although the BMD of the femoral neck was slightly increased on the prosthetic side (1.002 g/cm2) as opposed to the control side, this difference did not reach statistical significance.

CONCLUSION

The Birmingham resurfacing prosthesis does not appear to reduce femoral neck bone mineral density in comparison to the normal femoral neck bone density. We conclude that femoral neck fractures are unlikely to be due to stress shielding related to the prosthesis.

Odontoid lateral mass asymmetry: do we over-investigate?

OBJECTIVES

This study aimed to evaluate the necessity for further radiological investigation in patients with suspected traumatic rotatory subluxation of the atlanto-axial complex on plain radiography following acute cervical trauma and outline guidelines for assessment of patients with atlanto-axial asymmetry on plain radiography.

METHODS

A retrospective review of all patients who had undergone atlanto-axial CT scanning as a result of radiographic C1-C2 asymmetry following cervical spine trauma. The plain x ray and CT images were reviewed retrospectively and correlated with the clinical presentation and outcome.

RESULTS AND CONCLUSION

Records of 29 patients (16 men, 13 women; age range 21-44 years) were reviewed. All patients were found to have atlanto-odontoid asymmetry on the initial plain x ray. CT images of none of the patients revealed rotatory subluxation. Ten patients (32%) were found to have congenital odontoid lateral mass asymmetry. All patients were treated conservatively without any further intervention. On review, in 19 patients the orientation of the x ray beam in combination with head rotation was found to be at fault. Approximately 1050 trauma cervical spine x rays were taken in the department where this study was conducted over the period 1999-2001. This study identified 10 patients out of a total of 29 as having congenital odontoid lateral mass asymmetry. This represents approximately 1% of the patients attending the emergency department. Thus congenital odontoid lateral mass asymmetry should be considered in the differential diagnosis following acute cervical trauma.

Hylamer wear rates and shelf life: a clinical correlation

We evaluated the performance of 84 Hylamer polyethylene components and zirconia modular femoral heads which were implanted in a single institution over a 5 year period. Patients were followed up for a mean of 6.2 years. The mean rate of penetration was 0.58 mm/year (0.05-1.0). Lot/batch numbers were available in the clinical case notes of 54 patients. Using the lot/batch numbers, we were able to determine the Hylamer cups' shelf lifes. We found that liners with a shelf life greater than 10 months had a significantly greater linear wear (0.38 mm/year) than those implanted in less than 10 months (0.05 mm/year).

The need for multidisciplinary management of patients with upper thoracic spine fractures caused by high-velocity impact: a review of 32 surgically stabilised cases

PURPOSE

To analyse the characteristics of patients who underwent surgery for fractures of the upper thoracic spine (T1-T6) in our institution. The thoracic spine is supported by the rib cage and associated ligaments; therefore, displacement and fracture of the upper thoracic spine in healthy young adults require a great force. The relatively narrow spinal canal around the spinal cord in this area could result in severe neurological deficit should fractures occur.

METHODS

The treatment course of 32 patients (26 men and 6 women) who underwent surgery for fractures of the upper thoracic spine between February 1995 and March 2001 was retrospectively reviewed. Parameters of injuries and treatment methods were evaluated.

RESULTS

Of the 32 patients, 29 were injured in traffic accidents (15 motorcycle and 14 vehicle), 2 in falls, and one by a heavy door falling on his back. 29 patients had spinal fractures at more than one level. 23 patients had complete, 7 had incomplete, and 2 had no neurological deficit. 30 patients required multiple modalities of radiological imaging (in addition to plain radiography) for diagnosis. 20 patients sustained other injuries apart from spinal fractures, 15 of them had associated chest injuries.

CONCLUSION

High-velocity fractures of the upper thoracic spine are injuries with devastating consequences, and can result in severe neurological deficit and concomitant injuries. These patients are best treated by a multidisciplinary approach.

Percutaneous cementoplasty of acetabular bony metastasis

The development of malignant lesions in the acetabulum can lead to painful and disabling bone destruction. Lytic metastases of the acetabulum are frequent, causing pathologic fractures, pain and disability. The literature is sparse in relation to the exact indications and technique for this procedure. Percutaneous injection of methylmethacrylate or ethanol may provide marked pain relief or bone strengthening in patients, with malignant acetabular destruction, who are unable to tolerate surgery. Injection of methylmethacrylate is usually indicated when the weight-bearing part of the acetabulum is involved. The goals of treatment are pain relief and mechanical strengthening of the acetabulum. Radiography and computed tomography must be performed prior to therapeutic percutaneous injection to assess the location and extent of the lytic process, the presence of cortical destruction or fracture, and the presence of soft-tissue involvement. We report a case of a 39-year-old woman with a secondary acetabular lesion, which was treated successfully with percutaneous acetabular cementoplasty. We describe a novel technique used to inject cement into the lesion, allowing for greater cement volume and pressurisation within the lesion.

Anthropometrical analysis of cervical spine injuries

To date the principal focus of the mechanism of cervical spine fracture has been directed towards head/neck circumference and vertebral geometric dimensions. However the role of other measurements, including chest circumference and neck length, in a standard cervical fracture population has not yet been studied in detail. Cervical fractures often involve flexion/extension type mechanisms of injury, with the head and cervical spine flexing/extending, using the thorax as an end point of contact. Thus, the thorax may play an important role in neck injuries.

STUDY DESIGN

We prospectively studied all patients with cervical spine fractures who were admitted to the National Spinal Injuries Unit from 1 July 2000 to 1 March 2001. Anthropometrical measurement of head circumference, neck circumference, chest circumference, and neck length were analysed. Ages ranged from 18 to 55 years, and all patients with concomitant cervical pathology were excluded from the study. Mechanism of injury involved flexion/extension type injuries in all cases; those with direct axial loading were excluded. A control group of 40 patients (age 18-50 years) involved in high velocity trauma with associated long bone fractures, in whom cervical injury was suspected, but who were without any cervical fracture, or associated pathology, were similarly measured.

RESULTS

Our analysis revealed a statistically significant increase in chest size in the male control group versus the male fracture group (97.89 cm versus 94.19 cm, P < 0.05, Student's t-test). There was a correspondingly significant increase in chest circumference between the female controls versus the female fracture group (92.33 cm versus 88.88 cm, P < 0.05, Student's t-test). Our results revealed no statistical difference in head circumference, neck circumference, or neck length between each of the groupings. These results indicate a proportionately larger chest may be a protective factor in cervical spine fractures.

Outcome after single technique ankle arthrodesis in patients with rheumatoid arthritis

The established treatment for severe rheumatoid arthritis in the ankle is arthrodesis. Numerous reports in the literature describe outcomes in patients with degenerative and posttraumatic arthrosis and rheumatoid disease. This has led to results that are difficult to interpret. In addition, in the few studies that have evaluated patients with rheumatoid disease many techniques of arthrodesis are reported, further confounding assessment of one fusion method. One technique of 20 ankle fusions in patients with rheumatoid disease was evaluated. A modified Wagner arthrodesis was used through a transfibular approach using parallel compression screws. The scoring systems of Mazur et al, Moran et al, and the Short-Form-36 were used to evaluate the outcome. The mean time to followup was 3 years 10 months. Eighteen of 20 fusions obtained a solid talocrural union (90%). No correlation was found between the scores of Mazur et al and Moran et al. Correlation was achieved between the scores for the Short Form-36 and Moran et al. The modified Wagner ankle arthrodesis is a simple, reliable, reproducible technique with a 90% union rate. The value of the technique has been confirmed in patients with rheumatoid arthritis by evaluating the outcome using a scoring system that is validated and relevant to this population.

Recognition of progressive atlanto-occipital dislocation (by a changing neurologic status and clinical deformity)

We present a case of progressive atlanto-occipital dislocation, recognized by a new onset of positive neurologic findings. We discuss the anatomic relationship of the lower four cranial nerves to the foramen magnum and the atlanto-occipital joint. The importance of careful assessment of the cranial nerves prior to choosing a treatment algorithm is emphasized.

Bizarre parosteal osteochondromatous proliferation (Nora's lesion) of the sesamoid: a case report

We report the a case of Nora's lesion (Bizarre Parosteal Osteochondromatous Proliferation) of the sesamoid. A 32-year-old woman presented with a painless, enlarging mass of two years duration on the plantar aspect of the first metatarsophalangeal joint of the left foot. Radiographs, Computerized Tomographs and Magnetic Resonance images, initially suggested a parosteal osteosarcoma arising from the tibial sesamoid. The mass was excised, and a histological diagnosis of Bizarre Parosteal Osteochondromatous Proliferation of bone (Nora's lesion) was made. The aggressive growth of this lesion may suggest a neoplasm clinically. Histological features, however, are those of a reactive lesion.