Inter- and intra-observer reliability of the new AO/OTA classification of proximal femur fractures.

INTRODUCTION: Hip fractures are a global health burden, with an incidence that is projected to increase from 66,000/year currently in the United Kingdom to 100,000/year by 2033. The classification of intertrochanteric fractures is key to the treatment algorithms advising on their surgical management. The AO/OTA classification is the most commonly used system, initially published in 1990 and subsequently shown to have poor inter- and intra-observer reliability, it was revised in 2018 with the main aim of re-classifying and further defining the 31-A2 group. METHODS: 150 plain film anteroposterior and lateral plain film radiographs of intertrochanteric fractures from three hospitals were classified using the 2018 AO/OTA classification of intertrochanteric fractures by six Orthopaedic Surgeons (2 Consultants, 4 Trainees), all were blinded to the definitive surgical treatment for patients. Radiographs were re-classified after a minimum of 3-months, Cohen's Kappa for inter-observer reliability was calculated from first round classifications and intra-observer reliability from first and second classifications. RESULTS: Mean Kappa for inter-observer reliability for AO group classification (e.g. 31-A1) was 0.479 (0.220 - 0.771, for sub-group classification (e.g. 31-A1.1) reliability reduced to 0.376 (0.276 - 0.613). Intra-observer reliability was comparable for both group and sub-group classifications, 0.661 and 0.587 respectively. CONCLUSIONS: The revised 2018 AO/OTA classification aimed to simply the classification of intertrochanteric fractures, however it remains unreliable with only a "moderate" inter-observer reliability at group level with this falling to "fair" when sub-group classifications are made. Identification of stable and unstable injuries using the new AO/OTA system remains fraught with difficulties and appears difficult to apply with consistent accuracy.

Revision arthroplasty for periprosthetic femoral fracture using an uncemented modular tapered conical stem.

Periprosthetic femoral fracture (PFF) is a potentially devastating complication after total hip arthroplasty, with historically high rates of complication and failure because of the technical challenges of surgery, as well as the prevalence of advanced age and comorbidity in the patients at risk. This study describes the short-term outcome after revision arthroplasty using a modular, titanium, tapered, conical stem for PFF in a series of 38 fractures in 37 patients. The mean age of the cohort was 77 years (47 to 96). A total of 27 patients had an American Society of Anesthesiologists grade of at least 3. At a mean follow-up of 35 months (4 to 66) the mean Oxford Hip Score (OHS) was 35 (15 to 48) and comorbidity was significantly associated with a poorer OHS. All fractures united and no stem needed to be revised. Three hips in three patients required further surgery for infection, recurrent PFF and recurrent dislocation and three other patients required closed manipulation for a single dislocation. One stem subsided more than 5 mm but then stabilised and required no further intervention. In this series, a modular, tapered, conical stem provided a versatile reconstruction solution with a low rate of complications.

The relationship between operative and radiographic acetabular component orientation: which factors influence resultant cup orientation?

There is great variability in acetabular component orientation following hip replacement. The aims of this study were to compare the component orientation at impaction with the orientation measured on post-operative radiographs and identify factors that influence the difference between the two. A total of 67 hip replacements (52 total hip replacements and 15 hip resurfacings) were prospectively studied. Intra-operatively, the orientation of the acetabular component after impaction relative to the operating table was measured using a validated stereo-photogrammetry protocol. Post-operatively, the radiographic orientation was measured; the mean inclination/anteversion was 43° (sd 6°)/ 19° (sd 7°). A simulated radiographic orientation was calculated based on how the orientation would have appeared had an on-table radiograph been taken intra-operatively. The mean difference between radiographic and intra-operative inclination/anteversion was 5° (sd 5°)/ -8° (sd 8°). The mean difference between simulated radiographic and intra-operative inclination/anteversion, which quantifies the effect of the different way acetabular orientation is measured, was 3°/-6° (sd 2°). The mean difference between radiographic and simulated radiographic orientation inclination/anteversion, which is a manifestation of the change in pelvic position between component impaction and radiograph, was 1°/-2° (sd 7°). This study demonstrated that in order to achieve a specific radiographic orientation target, surgeons should implant the acetabular component 5° less inclined and 8° more anteverted than their target. Great variability (2 sd about ± 15°) in the post-operative radiographic cup orientation was seen. The two equally contributing causes for this are variability in the orientation at which the cup is implanted, and the change in pelvic position between impaction and post-operative radiograph.

Pelvic position and movement during hip replacement.

The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient's pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ± 32), obliquity -4° (2sd ± 12), rotation -8° (2sd ± 14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (sd 6). Factors influencing pelvic movement included surgeon, approach (posterior > lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ± 16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required.

Patient recall of surgical information after day case knee arthroscopy.

PURPOSE: Day case knee arthroscopy is frequently performed on dedicated lists designed to optimise the throughput of patients. This could affect patient recall of clinical information with clinical, ethical and medicolegal consequences. The purpose of this study was to assess patient recall after knee arthroscopy and identify potential contributory factors. METHODS: Seventy-two patients undergoing day case knee arthroscopy were provided with information about their surgery post-operatively and tested for recall of the information prior to discharge. All patients underwent cognitive assessment when information was delivered and again when tested. Patient recall was correlated with demographic and anaesthetic factors and a multivariate regression model was used to identify risk factors for reduced recall. RESULTS: Recall overall was poor. Significant independent risk factors for reduced recall were reduced cognitive state at the time of information delivery and a shorter time between surgery and information delivery. Duration of anaesthesia, use of sedatives and use of opiate analgesia were not significantly correlated with recall. CONCLUSIONS: Information recall after day case knee athroscopy may be suboptimal. Allowing more time between surgery and information delivery may improve recall. However, this may be difficult during the course of a busy list and surgeons should consider using additional techniques to improve patient recall after surgery to reduce the risk of patient anxiety or non-compliance. LEVEL OF EVIDENCE: IV.

The limits of precision in conventionally instrumented computer-navigated total knee arthroplasty.

PURPOSE: Computer-navigated total knee arthroplasty (TKA) improves the accuracy of component implantation. However, the final implant alignment may not match planned alignment. The hypothesis of this study is that although computer navigation improves alignment, imprecision may not be completely eliminated. The aim of the study was to establish the incidence and sources of imprecision during TKA using computer navigation to measure deviations from planned alignment. METHODS: Computer navigation was used to quantify changes in planned alignment at four steps during 136 TKA's: application of cutting blocks, addition of definitive pin fixation, bone cuts and after prosthesis application. Mean changes in alignment deviation at each step in each plane were measured and the number of significant outliers (>3° from the planned resection plane) were assessed in each plane. RESULTS: Overall changes in planned alignment were small and non-cumulative between steps but the incidence of outliers (cuts measured as >3° from planned alignment at each step) increased through the steps, with 21.3 % (n = 29) of final implants outlying in the tibial sagittal plane, which was the least precise plane. The highest number of outliers occurred after bone resection and the addition of pins to cutting blocks was also identified as a source of imprecision. CONCLUSION: Despite improved accuracy of bone resection with computer-navigated TKA, the precision of bone cuts may be affected at several steps of the procedure. Cutting block application, bone resection and prosthesis application may all affect accuracy. Bone cuts should be made with meticulous care, whether navigated or not, and navigated cuts should be checked and corrected, particularly in the tibial sagittal plane. LEVEL OF EVIDENCE: IV.

Segmental fracture of the scaphoid: report of a rare fracture pattern.

INTRODUCTION: To the best of our knowledge, there are no reports in the orthopaedic and trauma literature of true segmental fracture of the scaphoid bone. We present such a case with a brief discussion of the morphology and mechanisms of injury of scaphoid fractures and the problems they present, particularly in diagnosis. CASE HISTORY: A 43-year-old male with polytrauma sustained in a motorcycle road traffic accident was treated at our hospital. His injuries included a fracture initially thought to involve the waist of the scaphoid. Because he had bilateral upper limb injuries, we elected to treat the fracture surgically to facilitate rehabilitation. At the time of surgery, the fracture was noted to be truly segmental, an unsuspected and rare finding. The fracture was internally fixed, with a satisfactory result. DISCUSSION: Scaphoid fracture patterns are generally consistent and predictable, occurring most commonly through the waist of the bone. Mechanism for injury is thought to be hyperextension of the wrist. Comminution, with or without a butterfly fragment, is occasionally seen, as are simultaneous tuberosity fractures. We suggest that the mechanism in this case may have been multiple or secondary trauma, or an effect of loaded rotation. We highlight the need for careful imaging of the scaphoid bone prior to choosing treatment.