Adeel Aqil

Developmental dysplasia of the hip in the newborn: A systematic review.

Developmental dysplasia of the hip (DDH) denotes a wide spectrum of conditions ranging from subtle acetabular dysplasia to irreducible hip dislocations. Clinical diagnostic tests complement ultrasound imaging in allowing diagnosis, classification and monitoring of this condition. Classification systems relate to the alpha and beta angles in addition to the dynamic coverage index (DCI). Screening programmes for DDH show considerable geographic variation; certain risk factors have been identified which necessitate ultrasound assessment of the newborn. The treatment of DDH has undergone significant evolution, but the current gold standard is still the Pavlik harness. Duration of Pavlik harness treatment has been reported to range from 3 to 9.3 mo. The beta angle, DCI and the superior/lateral femoral head displacement can be assessed via ultrasound to estimate the likelihood of success. Success rates of between 7% and 99% have been reported when using the harness to treat DDH. Avascular necrosis remains the most devastating complication of harness usage with a reported rate of between 0% and 28%. Alternative non-surgical treatment methods used for DDH include devices proposed by LeDamany, Frejka, Lorenz and Ortolani. The Rosen splint and Wagner stocking have also been used for DDH treatment. Surgical treatment for DDH comprises open reduction alongside a combination of femoral or pelvic osteotomies. Femoral osteotomies are carried out in cases of excessive anteversion or valgus deformity of the femoral neck. The two principal pelvic osteotomies most commonly performed are the Salter osteotomy and Pemberton acetabuloplasty. Serious surgical complications include epiphyseal damage, sciatic nerve damage and femoral neck fracture.

Panton-Valentine leukocidin osteomyelitis in children: a growing threat

Panton-Valentine leukocidin-producing Staphylococcus aureus osteomyelitis is associated with multiple complications including multiple abscesses, deep vein thrombosis and fulminant sepsis. This article reviews the literature concerning this emerging threat which is currently under-recognized.

Use of robotic technology in cam femoroacetabular impingement corrective surgery

Cam type femoroacetabular impingement (FAI) is an anatomical disorder that can lead to osteoarthritis (OA) of the hip joint. With existing surgical options there is invariably a tendency for under‐resection or over‐resection of the cam lesion, both having dire consequences. This study assessed the application of robotic technology in the surgical management of cam FAI.

Abnormal ground reaction forces lead to a general decline in gait speed in knee osteoarthritis patients

AIM To analyse ground reaction forces at higher speeds using another method to be more sensitive in assessing significant gait abnormalities. METHODS A total of 44 subjects, consisting of 24 knee osteoarthritis (OA) patients and 20 healthy controls were analysed. The knee OA patients were recruited from an orthopaedic clinic that were awaiting knee replacement. All subjects had their gait patterns during stance phase at top walking speed assessed on a validated treadmill instrumented with tandem force plates. Temporal measurements and ground reaction forces (GRFs) along with a novel impulse technique were collected for both limbs and a symmetry ratio was applied to all variables to assess inter-limb asymmetry. All continuous variables for each group were compared using a student t-test and χ2 analysis for categorical variables with significance set at α = 0.05. Receiver operator characteristics curves were utilised to determine best discriminating ability. RESULTS The knee OA patients were older (66 ± 7 years vs 53 ± 9 years, P = 0.01) and heavier (body mass index: 31 ± 6 vs 23 ± 7, P < 0.001) but had a similar gender ratio when compared to the control group. Knee OA patients were predictably slower at top walking speed (1.37 ± 0.23 m/s vs 2.00 ± 0.20 m/s, P < 0.0001) with shorter mean step length (79 ± 12 cm vs 99 ± 8 cm, P < 0.0001) and broader gait width (14 ± 5 cm vs 11 ± 3 cm, P = 0.015) than controls without any known lower-limb joint disease. At a matched mean speed (1.37 ± 0.23 vs 1.34 ± 0.07), ground reaction results revealed that push-off forces and impulse were significantly (P < 0.0001) worse (18% and 12% respectively) for the knee OA patients when compared to the controls. Receiver operating characteristic curves analysis demonstrated total impulse to be the best discriminator of asymmetry, with an area under the curve of 0.902, with a cut-off of -3% and a specificity of 95% and sensitivity of 88%. CONCLUSION Abnormal GRFs in knee osteoarthritis are clearly evident at higher speeds. Analysing GRFs with another method may explain the general decline in knee OA patient’s gait.

Validation of the ‘FeMorph’ software in planning cam osteochondroplasty by incorporating labral morphology

Impingement resulting from a cam deformity may cause pain, limit the hip joint range of motion (RoM) and lead to osteoarthritis. We have previously developed FeMorph software to quantify and plan corrective surgery and predict hip RoM post surgery. This study aimed to validate the software and evaluate the influence of the acetabular labrum on hip RoM. Computed tomography data from 92 femur-pelvis pairs were analysed in conjunction with the inter/intra-observer reliability. Four cadaveric hips were dissected, and the three-dimensional (3D) shape and size of the acetabular labrum for these hips was obtained using laser scan. The influence of the acetabular labrum in the RoM and subsequent planning for corrective surgery were then evaluated in cadavers for models with and without a labrum, and used as a first step towards validation of FeMorph RoM prediction. FeMorph was successfully used to model cam deformities and plan corrective surgery. Three-dimensional alpha angles were reduced to below 50° after virtual surgery without an excessive reduction in femoral neck cross-sectional area, which could increase fracture risk. A mean increase of 8° ± 2° in permitted internal rotation was observed during impingement testing following removal of the labrum. FeMorph provides a reliable and useful method to model and plan cam deformity correction. This study indicates that the presence of the labrum is responsible for a substantial decrease in permitted internal rotation at the hip joint. This has implications for surgical planning models which often only account for bony impingement.

Does cam osteochondroplasty compromise proximal femur strength

Little is known about the effect on load bearing ability of cam-type femurs following osteochondroplasty. The aim of this study was to compare the change in deformation undergone by cam-type femoral acetabular impingement femur models after resection of different volumes. Dry-bone replicas (N = 10) of two cam-type femurs (cam A and B) underwent resections of increasing volume (Surgery I, II and III) representing conservative, adequate and radical resections. Deformation under cyclic loading of 700 N for five cycles after each surgery was compared. The 360° alpha angle and the change in head to neck ratio at four equidistant points along the femoral neck were used as measures of surgical efficacy and volume resected. Intact cam A and B replicas had a maximum alpha angle of 88° and 90°, respectively, which were reduced to 55° and 54° post Surgery I. Cam A replicas showed a significant reduction (p < 0.01) in mean axial displacement after Surgery I (up to 10% reduction in neck volume) and an increase after Surgery III (~20%–40% reduction in neck volume) compared to unresected controls (p < 0.01). Surgery II (~10%–15% reduction in neck volume) produced no significant change in mean displacement (p > 0.05). Cam B models exhibited lower mean displacement after Surgery I, II and III (p < 0.01) compared to unresected controls. Conservative surgery appears to improve the axial load bearing ability of dry-bone models. Radical resections may significantly decrease the fracture-resistant properties of bone following osteochondroplasty which should be noted when planning such a procedure.

Birmingham Mid-Head Resection Periprosthetic Fracture

Total hip arthroplasty in the young leads to difficult choices in implant selection. Until recently bone conserving options were not available for younger patients with deficient femoral head bone stock. The novel Birmingham Mid-Head Resection (BMHR) device offers the option of bone conserving arthroplasty in spite of deficient femoral head bone stock. Femoral neck fracture is a known complication of standard resurfacing arthroplasty and is the most common reason for revision. It is unknown whether this remains to be the case for the BMHR neck preserving implants. We report a case of a 57-year-old male, who sustained a periprosthetic fracture following surgery with a BMHR arthroplasty. This paper illustrates the first reported case of a BMHR periprosthetic fracture. The fracture pattern is spiral in nature and reaches to the subtrochanteric area. This fracture pattern is different from published cadaveric studies, and clinicians using this implant should be aware of this as revision is likely to require a distally fitting, rather than a metaphyseal fitting stem. We have illustrated the surgical technique to manage this rare complication.

Patient-specific guides improve hip arthroplasty surgical accuracy

Abstract The role of patient-specific (PS) technology in total hip arthroplasty remains relatively unexplored. We asked whether PS guides: (1) Reduced average surgical errors? (2) Reduced outlier error frequencies? (3) Could predict the size of implants used? A single surgeon implanted femurs using either standard or PS guides and was blinded to the pre-operative plans. There were significant differences in median leg length errors between standard (3.3 mm) and PS groups (1.4 mm), U = 110, z = –2.3, p = 0.02. In contrast to the PS group, the standard group had significantly more outlier errors and frequently undersized implants. PS guides improve hip arthroplasty surgical accuracy.Abbreviations: PS: patient specific; THA: total hip arthroplasty; LLD: leg length discrepancies; HRA: hip resurfacing arthroplasty

Letter to the Editor regarding ‘How symmetric are metal-on-metal hip resurfacing patients during gait? Insights for the rehabilitation’

http://dx.doi.org/10.1016/j.jbiomech.2017.07.037 0021-9290/ 2017 Elsevier Ltd. All rights reserved. We read with great interest the article written by Resende and colleagues (Resende et al., 2017) entitled, ‘How symmetric are metal-on-metal hip resurfacing patients during gait? Insights for the rehabilitation’ Hip resurfacing arthroplasty (HRA) is a contentious subject given the high profile withdrawal of the DePuy Orthopaedic ASR metal-on-metal (MoM) implant (DePuy-ASR) due to high failure rates (de Steiger et al., 2011; Prosser et al., 2010). In their welldesigned kinematic study (Resende et al., 2017), the authors assessed whether a unilateral DePuy ASR HRA can result in symmetric gait. We applaud such a study, which aims to take assessment beyond functional scores, which have many well-documented limitations (Fitzpatrick et al., 1998). Despite analysing a withdrawn implant, the study demonstrates that all 12 ASR HRA patients having reported no pain. This is particularly reassuring as the mean time from surgery to gait assessment was 45 months, which puts this group of patients at the highest risk as most revisions occur in the early mid-term (Curtin et al., 2017; Laaksonen et al., 2017). Sadly, though, there was no mention of serum metal ions. It is well reported that raised serum metal ions are correlated to adverse local tissue reactions (ALTRs) (Laaksonen et al., 2017; Reito et al., 2013), which would negatively alter hip biomechanics. The prevalence of ALTRs in asymptomatic patients is also high (Chang et al., 2012; WynnJones et al., 2011). Moreover, the research looked at lower limb kinematic function and there is no evidence that these patients had any further imaging (ultrasound or MARS MRI) to ensure that there was not any surrounding soft tissue destruction. These omissions, which are now standard recommendations (MHRA, 2017), make it difficult to conclude as to whether these were well functioning or failing hips. Furthermore the authors present what appears to be a retrospective study as no preoperative data was presented. It is important to have baseline data in order to appreciate the effect of the intervention, which could be significantly worse or better. A single snapshot study, particularly with small numbers, could easily draw incorrect conclusions. Given this, the title of this paper would be better changed to ‘How symmetric are ASR hip resurfacing patients during gait’. Instead, the current title of the study would be better addressed by prospectively evaluating a HRA implant with a proven track record to answer the important question of whether HRA results in symmetric gait, and to give insight for rehabilitation. Conflict of interest