Computer Hexapod-assisted Orthopaedic Surgery for the Correction of Multiplanar Deformities throughout the Lower Limb.

Introduction: Computerised hexapod-assisted orthopaedic surgery (CHAOS) is a method by which complex multiplanar, multilevel deformity can be corrected with a high degree of accuracy utilising minimally invasive techniques within a single operative event. This study's aim was to report the reliability, accuracy and magnitude of correction achieved, alongside patient-reported outcomes and risk factors for complications when using the CHAOS technique throughout the lower limb. Materials and methods: Retrospective review of medical records and radiographs for consecutive patients who underwent CHAOS for lower limb deformity correction at a tertiary centre between 2012 and 2020. Results: There were 70 cases in 56 patients, with the site of surgery being the femur in 48 cases, proximal tibia in 17 and distal tibia in 5 cases. Multiplanar correction was performed in 43 cases, and multilevel osteotomy was undertaken in 23 cases. Fixation was undertaken with intramedullary nailing (IMN) in 49 cases and locked plates in 21.The maximum corrections were 40° rotation, 20° coronal angulation, 51° sagittal angulation and 62-mm mechanical axis deviation (MAD). Deformity correction was mechanically satisfactory in all patients bar one who was undercorrected requiring revision. The mean patient global impression of change (PGIC) score was 6.2 out of 7.Overall complication rate was 12/70 (17%). Complications from femoral surgery included two nonunions, one case of undercorrection, one case of stiffness, one muscle hernia and one pulmonary embolism. Complications from tibial surgery were one compartment syndrome, one pseudoaneurysm of the anterior tibial artery requiring stenting, one transient neurapraxia of the common peroneal nerve, one locking plate fatigue failure, one seroma and one superficial wound infection. Conclusion: Computerised hexapod-assisted orthopaedic surgery can be used for accurate correction of complex multilevel and multiplanar deformities of both the femur and tibia. The risk profile appears to differ between femoral and tibial surgeries, and also to that of traditional circular frame correction. Patients remain highly satisfied with both the functional and symptomatic outcomes. How to cite this article: French JMR, Filer J, Hogan K, et al. Computer Hexapod-assisted Orthopaedic Surgery for the Correction of Multiplanar Deformities throughout the Lower Limb. Strategies Trauma Limb Reconstr 2024;19(1):9-14.

The effect of COVID-19 lockdown restrictions on oswestry disability index scores: a comparative cross-sectional study.

PURPOSE: Lockdown measures to combat the COVID-19 pandemic restricted social interactions and travel. This retrospective, observational study was conducted to evaluate the effect of lockdown restrictions on Oswestry Disability Index (ODI) scores in patients with spinal conditions. METHODS: Prospectively collected data from the British Spine Registry were retrospectively analysed in two groups. The study group included patients' baseline pre-operative ODI scores collected during the first national lockdown in the UK between March and May 2020. The reference group included ODI scores recorded during the same period in 2019, before the pandemic. Scores were compared between groups using the Mann-Whitney U test. We also calculated modified scores that omitted responses to questions related to travel and social life. These were compared using Wilcoxon matched-pairs signed-rank test and Bland-Altman analyses. RESULTS: The median ODI scores for the reference and lockdown groups were 49 and 45, respectively, with no significant differences in the mean ranks (p = 0.068). Comparisons of original and modified ODI scores showed different outcomes for each study group. No significant differences were observed in the lockdown group (p = 0.06). However, for the pre-COVID-19 reference group, there was a significant difference (p < 0.01). Bland-Altman analyses showed reasonable agreement between the methods for calculating ODI in both groups. CONCLUSION: We found no clinically important differences in ODI scores between the two groups. The findings suggest that the ODI is reliable during lockdown situations and can be used with confidence in the future research using both retrospective and prospective data. LEVEL OF EVIDENCE: Level 3.

The Influence of Critical Shoulder Angle in Secondary Rotator Cuff Failure After Shoulder Replacement: An Age- and Sex-Matched Case-Control Study.

Introduction Decreased or increased critical shoulder angles (CSA) are associated with osteoarthritis or rotator cuff failure respectively. Secondary cuff failure after shoulder arthroplasty is disabling and often requires additional surgery. The aim of this study was to investigate if the initial CSA correlated with cuff failure in the context of shoulder arthroplasty. Methods Patients from a tertiary referral centre were reviewed from 2011-2017. Those who underwent revision from hemiarthroplasty (HA) or anatomic total shoulder arthroplasty (TSA) to a reverse shoulder arthroplasty (RSA) following rotator cuff failure were compared to an age and sex-matched control group. The CSA was calculated from initial pre-operative radiographs. Results In this study, 16 patients with symptomatic cuff failure after anatomic TSA or HA requiring revision to RSA were compared to a control group of 16 age- and sex-matched patients showing no signs of symptomatic cuff failure. The median CSA in the study group was significantly greater than that of the control group (31.5o, IQR = 29.8 - 36.1o vs. 29.5o, IQR = 27.6 - 30.4o; p= 0.026). Conclusion The difference in CSA between those who required revision for secondary cuff failure than those who didn't suggest that pre-operative measurement of CSA may help guide surgical planning in shoulder arthroplasty.

Haemorrhagic Pseudotumour Following Metal-on-Metal Hip Replacement.

We present a unique report of a spontaneous haemorrhage into a pseudotumour five years following revision surgery for failed metal-on-metal hip arthroplasty. The patient sustained no trauma, was not taking anticoagulants and had no bleeding disorder. Rapid progression in the size of the pseudotumour caused significant symptoms and functional impairment. Surgical excision was recommended by a national specialist centre, but with conservative management, significant regression of the pseudotumour was noted, with complete resolution of symptoms. This case is the first report of haemorrhage into a pseudotumour, which is an important differential and can be managed non-operatively.

Assessing distal radius malrotation following fracture using computed tomography.

HYPOTHESIS: When the distal fracture fragment in distal radius fractures displaces, it commonly rotates as well as shortens and angulates. AIM: The aim of this study was to assess the frequency and magnitude of malrotation of the distal fracture fragment using computed tomography (CT). METHODS: A retrospective radiological assessment of 85 CT scans of the distal radius, 35 following fracture and 50 normal radii, was carried out. We developed and applied a simple method for measuring rotation of the distal radius relative to the diaphysis using routine CT scans of the wrist. A Mann-Whitney analysis was used to identify differences in radial rotation between fractures and controls. Intra- and inter-observer reliability were analyzed using intra-class correlation coefficients (ICCs) and Bland-Altman plots. RESULTS: The articular surface of the distal radius is normally rotated in the long axis of the forearm relative to the diaphysis, either into pronation or into supination. The median radial rotation angle of controls was 1° pronation (range -15° to 4°) compared to 3° pronation (range -24° to 31°) in the fracture group. The absolute rotation angle was significantly greater in the fracture group (median 10°, range 0-31° vs. 3°, range 0-15°; p < 0.001) and outside the "normal range" of controls in 26 cases indicating that 75% had rotated appreciably following injury. Intra- and inter-observer reliability of measurements were good with ICCs of 0.99 and 0.98, respectively. CONCLUSIONS: Malrotation of the distal radius appears common following distal radius fracture. Malrotation of the distal fracture fragment has been shown to affect distal radio-ulnar joint function. Despite this, rotational deformity is rarely addressed in clinical practice as it is difficult to appreciate on simple radiographs. The simplified method described here is easy to use in routine clinical practice and also appears reliable. Measuring radial rotation may be an important consideration when planning both primary treatment and corrective osteotomy for patients with distal radial malunion.

Improving the accuracy of digital templating: achieving success through stakeholder management.

The use of a marker ball in digital templating for hip arthroplasty is a well-established method of preoperative planning and is used to overcome the inherent magnification in plain film radiographs. Our hospital policy is to place a marker ball in all anteroposterior pelvic films taken in the emergency department (ED) which have been requested for suspected neck of femur fractures. We carried out a baseline measurement followed by three Plan-Do-Study-Act cycles for all pelvic films taken in ED during July 2016, November 2016, February 2017 and November 2017. Interventions between the baseline measurement and cycle 1 were to educate the lead radiographer and publish the results in the radiology newsletter, and between cycles 1 and 2 was to run a teaching session for radiographers, display posters in the X-ray department and place an electronic prompt on the X-ray machine to alert them of the need to place a marker ball in the X-ray field. Cycle 3 looked to see if improvements were sustained. 16/81 (20%) radiographs complied with the policy in our baseline measurement; 25/51 (46%, p=0.002) in cycle 1; 40/54 (74%, p=0.0056) in cycle 2; and 48/63 (76%) in cycle 3. Our quality improvement project led to large improvements in clinical practice through straightforward, small, but appropriately targeted interventions. Stakeholder management is key to successfully implementing change. The next step is to switch from the VoyantMark to the KingMark marker ball, as it has greater accuracy of templating and is also easier to place within the field of an X-ray.