Tibial tuberosity-trochlear groove distance: does it measure up?

Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability. Cite this article: Bone Jt Open 2022;3(3):268-274.

The influence of patellofemoral stabilisation surgery on joint congruity: an MRI surface mapping study.

BACKGROUND: In the unstable patellofemoral joint (PFJ), the patella will articulate in an abnormal manner, producing an uneven distribution of forces. It is hypothesised that incongruency of the PFJ, even without clinical instability, may lead to degenerative changes. The aim of this study was to record the change in joint contact area of the PFJ after stabilisation surgery using an established and validated MRI mapping technique. METHODS: A prospective MRI imaging study of patients with a history of PFJ instability was performed. The patellofemoral joints were imaged with the use of an MRI scan during active movement from 0° through to 40° of flexion. The congruency through measurement of the contact surface area was mapped in 5-mm intervals on axial slices. Post-stabilisation surgery contact area was compared to the pre-surgery contact area. RESULTS: In all, 26 patients were studied. The cohort included 12 male and 14 female patients with a mean age of 26 (15-43). The greatest mean differences in congruency between pre- and post-stabilised PFJs were observed at 0-10 degrees of flexion (0.54 cm2 versus 1.18 cm2, p = 0.04) and between 11° and 20° flexion (1.80 cm2 versus 3.45 cm2; p = 0.01). CONCLUSION: PFJ stabilisation procedures increase joint congruency. If a single axial series is to be obtained on MRI scan to compare the pre- and post-surgery joint congruity, the authors recommend 11° to 20° of tibiofemoral flexion as this was shown to have the greatest difference in contact surface area between pre- and post-operative congruency.

Does Partial Knee Replacement Allow Return to High-Demand Activities?

Purpose  The purpose of this study was to assess postoperative partial knee replacement (PKR) functional improvement using the postoperative Oxford Knee Score for Activity and Participation Questionnaire (OKS-APQ). PKR includes medial, lateral, and patellofemoral knee arthroplasty. Methods A search of a National Health Service hospital database was made to identify eligible candidates for a survey of Patient-Reported Outcome Measure (PROM). Database records were collected for patients who had medial, lateral, and patellofemoral knee arthroplasty. The first author, an orthopaedic surgery resident, retrospectively reviewed the data and selected 318 patient records for inclusion in a questionnaire survey. The inclusion criteria were: patients who had PKR within three years from the time of the study and patients who don't have medical problems that may affect their mobility; for example, balance problems. The survey used the postoperative Oxford Knee Score for Activity and Participation Questionnaire (OKS-APQ), Tegner Activity Score (TAS), and four questions were added to the present study, namely, three free-text questions and one visual analogue score (VAS). The survey was sent by post seeking the patients' responses. Results  Two-hundred five responded to the survey out of 318; a 64% response rate. The ceiling and floor effects were determined from patients' answers. Survey questions included: What is the most demanding activity you routinely do every month on your new knee? The patients' answers were divided into four groups. First, 29% were limited to low functional demand activities, for example, light walking for less than a mile. Second, 43% were involved in domestic work and sports activities, for example, golf, skittles, bowling, squatting, swimming, and gardening. Third, 21% had progressed to higher demand activities, for instance, dancing, racquet sports, cycling, and yoga. Fourth, 7% were performing higher demand activities involving impacts, for example, skiing, heavy gym workout, and marathon running. Conclusion The postoperative questionnaire demonstrated activities ranging from high-impact activities, for example, skiing, and from higher demand activities, for example, dancing to low function activities, for example, light walking.

Benefits of powered standing wheelchair devices for adolescents with Duchenne muscular dystrophy in the first year of use.

AIM: Poorer physical and mental health often accompany loss of walking in Duchenne muscular dystrophy. This study assessed the impacts of powered wheelchair standing device (PWSD) use on muscle and joint pain, joint angles when standing and mental health in adolescents with Duchenne muscular dystrophy. METHODS: Fourteen adolescents and parents participated in a stepped wedge design study over 12 months. During a baseline and intervention period, adolescents described pain and mental health, and parents reported their child's mental health. Video data were collected to measure hip, knee and ankle joint angles in the preferred standing position. RESULTS: Compared with baseline and adjusting for covariates, standing wheelchair use was associated with no change in muscle or joint pain or videoed joint angles in standing. Child-reported Strengths and Difficulties total scores decreased (coefficient -3.1, 95% confidence interval -4.6, -1.5); and parent-reported Personal Adjustment and Role Skills Scale total scores increased (coefficient 7.9, 95% confidence interval 3.3-12.5). CONCLUSIONS: PWSD use was associated with maintenance of musculoskeletal status and advantages to mental health. Long-term observations are necessary to improve understanding of how to support wellbeing in adolescents with Duchenne muscular dystrophy.

Screening for Carpal Tunnel Syndrome in Patients With Mucopolysaccharidosis.

Mucopolysaccharidoses (MPSs) are a group of rare lysosomal storage diseases with multisystem manifestations, including carpal tunnel syndrome (CTS). This study comprised a systematic review of literature and hospital guidelines addressing the method and frequency of screening for carpal tunnel syndrome in mucopolysaccharidosis patients and a review of carpal tunnel syndrome in patients seen in the multidisciplinary mucopolysaccharidosis clinic of a pediatric hospital, in order to develop screening recommendations. The literature reported the importance of routine carpal tunnel syndrome screening from early childhood in patients with mucopolysaccharidosis I, II, IV, and VI. Screening methods included physical examination, nerve conduction studies, electromyography, and ultrasonography. Ten of 20 mucopolysaccharidosis patients in our series underwent carpal tunnel syndrome surgery. Given the high incidence of carpal tunnel syndrome at a young age in mucopolysaccharidosis, the authors recommend performing physical examination and obtaining patient and caregiver history for carpal tunnel syndrome every 6 months from the time of mucopolysaccharidosis diagnosis, supplemented by annual nerve conduction studies in cases with poor history or equivocal examination.

Plate and screw fixation of arthroscopically assisted tibial tuberosity osteotomy: technique and results.

INTRODUCTION: We describe a fixation technique for tibial tuberosity osteotomies (TTO) utilising a plate and screw construct which adheres to established principles of bone healing. We record and discuss the complication profile and benefits of this technique. METHOD: The technique is outlined, and thirty consecutive case of TTO fixed with this combination of plate and screws were analysed during a study period from January 2018 to October 2018. All patients were followed up clinically to 3 months post-operation for the purpose of identifying early complications of surgery. Radiographic series were reviewed at 2, 6 and 12 weeks post-operation for evidence of fracture, loss of position, hardware failure and union. RESULTS: All cases went on to clinical and radiographic union by 12 weeks. We identified one case of hardware failure, one case of superficial infection and one case of stiffness requiring manipulation. CONCLUSION: We have found this technique of plate and screw construct to be effective in arthroscopically assisted TTO fixation leading to consistent union without loss of position with a low complication profile.

VIS-IT: Visualizing the Injured Tibia-A Cadaveric Study of Limb Positioning for Posterolateral Tibial Plateau Fracture Visualization.

Posterolateral tibial plateau (PLTP) fractures are often associated with anterior cruciate ligament (ACL) incompetence, such as tibial eminence fractures. Both occur from a pivot shift like mechanism. Malreductions of the tibial plateau most frequently occur in the posterolateral quadrant. Acquiring adequate intraoperative visualization of the PLTP poses a challenge. We hypothesized that visualization of PLTP could be improved by positioning the knee at 110 degrees of flexion with the addition of a varus anterolateral rotatory vector. This position and maneuver take advantage of both the nonisometric nature of the lateral soft tissues and, when present, ACL incompetence. In this cadaveric study, we digitally quantified the percentage of the lateral tibial plateau visualized under different conditions after performing an anterolateral surgical approach with submeniscal arthrotomy. Four conditions were assessed for articular visualization: (1) 30 degrees of knee flexion, (2) 110 degrees of knee flexion, (3) 110-degrees of knee flexion plus varus anterolateral rotatory vector, (4) 110-degrees of knee flexion plus varus anterolateral rotatory vector with ACL sacrifice (ACL incompetence model). In the ACL competent models, maximal lateral tibial plateau exposure was obtained with the knee positioned at 110 degrees of flexion with a varus anterolateral rotatory vector (58.2%, range: 52.9-63.4%). Articular visualization was further improved with the ACL incompetent model (82.4%, range: 77.1-87.7%), modeling a tibial eminence fracture.

Tarsal tunnel syndrome in the mucopolysaccharidoses: A case series and literature review.

BACKGROUND: The mucopolysaccharidoses (MPS) are a group of inherited, progressive, multi-system lysosomal storage disorders. Musculoskeletal manifestations include nerve entrapment syndromes, most commonly carpal tunnel syndrome. Tarsal tunnel syndrome (TTS) has also been reported. The purpose of this study was to investigate the clinical course of MPS patients with suspected TTS and to conduct a literature review of TTS in MPS. METHODS: A review of the Medline and EMBASE databases was conducted in accordance with published guidelines from the Joanna Briggs Institute of Evidence Based Medicine with search strategy developed by a librarian trained in systematic reviews. A medical record review was undertaken for all patients managed in the multi-disciplinary MPS clinic in a tertiary referral paediatric centre, identifying patients with a suspected or established diagnosis of TTS. Data regarding the demographics, investigations, presentation, management, and clinical course were collected. RESULTS: The literature review failed to identify any published papers regarding TTS in MPS, with conference proceedings only identified. Within a cohort of 19 MPS patients, four patients with a suspected diagnosis of TTS were identified (MPS I: two patients, MPS VI: two patients). Three patients underwent surgical tarsal tunnel decompression, two with good result. One patient had overlapping symptoms with spinal stenosis and improvement in suspected tarsal tunnel symptoms following spinal decompression and fusion.

Tibial Tuberosity Transfer in Combination With Medial Patellofemoral Ligament Reconstruction: Surgical Technique.

The stability of the patellofemoral joint relies on the tenuous interplay of soft tissue and bony factors. Anatomic risk factors for instability include a shallow trochlea, an abnormally lateral tibial tubercle position, patella alta, hypermobility, or a secondary injury to the medial patellofemoral ligament (MPFL). There is an increasing interest in restoring normal anatomy to achieve stability, and at times more than 1 abnormality exists. This article describes the technique for combining a tibial tuberosity transfer and an MPFL reconstruction. The key features include planning of skin incisions to enable both operations to be undertaken, planning of the screw placement before osteotomy is performed and assessment of the joint through a superolateral portal to assess the need for MPFL reconstruction after tuberosity transfer.

Neurophysiological profile of peripheral neuropathy associated with childhood mitochondrial disease.

INTRODUCTION: Peripheral nerve involvement is common in mitochondrial disease but often unrecognised due to the prominent central nervous system features. Identification of the underlying neuropathy may assist syndrome classification, targeted genetic testing and rehabilitative interventions. METHODS: Clinical data and the results of nerve conduction studies were obtained retrospectively from the records of four tertiary children's hospital metabolic disease, neuromuscular or neurophysiology services. Nerve conductions studies were also performed prospectively on children attending a tertiary metabolic disease service. Results were classified and analysed according to the underlying genetic cause. RESULTS: Nerve conduction studies from 27 children with mitochondrial disease were included in the study (mitochondrial DNA (mtDNA) - 7, POLG - 7, SURF1 - 10, PDHc deficiency - 3). Four children with mtDNA mutations had a normal study while three had mild abnormalities in the form of an axonal sensorimotor neuropathy when not acutely unwell. One child with MELAS had a severe acute axonal motor neuropathy during an acute stroke-like episode that resolved over 12months. Five children with POLG mutations and disease onset beyond infancy had a sensory ataxic neuropathy with an onset in the second decade of life, while the two infants with POLG mutations had a demyelinating neuropathy. Seven of the 10 children with SURF1 mutations had a demyelinating neuropathy. All three children with PDHc deficiency had an axonal sensorimotor neuropathy. Unlike CMT, the neuropathy associated with mitochondrial disease was not length-dependent. CONCLUSIONS: This is the largest study to date of peripheral neuropathy in genetically- classified childhood mitochondrial disease. Characterising the underlying neuropathy may assist with the diagnosis of the mitochondrial syndrome and should be an integral part of the assessment of children with suspected mitochondrial disease.

Adolescent knee pain and patellar dislocations are associated with patellofemoral osteoarthritis in adulthood: A case control study.

BACKGROUND: There is a lack of information about the association between patellofemoral osteoarthritis (PFOA) and both adolescent anterior knee pain (AKP) and previous patellar dislocations. METHODS: This case-control study involved 222 participants from our knee arthroplasty database answering a questionnaire. One hundred and eleven patients suffering from PFOA were 1:1 matched by gender with a unicompartmental tibiofemoral arthritis control group. Multivariate correlation and binary logistic regression analysis were performed, with odds ratios (ORs) and 95% confidence intervals (CIs) calculated. RESULTS: An individual is 7.5 times more likely to develop PFOA if they have suffered from adolescent AKP (OR 7.5, 95% CIs 1.51 to 36.94). Additionally, experiencing a patellar dislocation increases the likelihood of development of PFOA, with an adjusted odds ratio of 3.2 (95% CIs 1.25 to 8.18). A 44-year difference in median age of first dislocation was also observed between the groups. CONCLUSION: This should bring into question the traditional belief that adolescent anterior knee pain is a benign pathology. Patellar dislocation is also a significant risk factor. These patients merit investigation, we encourage clinical acknowledgement of the potential consequences when encountering patients suffering from anterior knee pain or patellar dislocation.

Patellar instability and quadriceps avoidance affect walking knee moments.

PURPOSE: To classify patients with patellofemoral (PF) instability on the basis of their mechanical gait characteristics, and to relate gait deficits to patellofemoral congruence. METHODS: Thirteen patients awaiting patellar stabilisation surgery were recruited for gait analysis and magnetic resonance imaging, MRI assessment of PF congruence. Patients were grouped into two subgroups (P1, P2) based on knee joint moment during stance, and their total support moments (TSMs) during stance were compared against eight healthy Control subjects. PF congruence was compared between groups from MRI data captured at 0, 20 and 40° of passive knee flexion and during dynamic extension. RESULTS: Five patients were classified into group P1 because they demonstrated a knee extensor moment during early stance, and eight patients into group P2 because they did not. The TSM of the more affected limb in group P1 was not significantly different from Control values in early stance but the difference was significant (P<.05) in late stance. In group P2, both the less and more affected limbs were significantly different from Control TSM values in early stance, but only the more affected limb in late stance. Patellofemoral contact areas as measured by MRI were greatest for the Control patients, and least for patient group P2 especially during the active extension trials. CONCLUSIONS: Patients with patellofemoral pain and instability walked with a slightly flexed knee, avoiding extension. The MRI measurements of joint contact agreed with the patient groupings according to gait mechanics. Cartilage contact across the PF joint can be an objective measure of instability.

A population-based post mortem study of sudden unexpected death in epilepsy.

The aim of this study was to review population autopsy data on epilepsy-related deaths (ERD) in Queensland, Australia, to establish the incidence of autopsy-confirmed sudden unexpected death in epilepsy (SUDEP), explore factors associated with SUDEP, and determine if complete autopsy examinations of SUDEP were performed. All autopsy reports for a 5year period in Queensland were electronically searched for the terms 'epilepsy' or 'seizure'. The identified reports were reviewed, and data were extracted for all ERD. In the study period, 175 ERD were identified from autopsy records (123 SUDEP, 34 accident-related, 3 due to status epilepticus). From data available on the prevalence of epilepsy in Queensland (National Health Survey), the incidence of autopsy-confirmed SUDEP was 0.7 per 1000 person years (95% confidence interval 0.5-1.2 per 1000 person years). The factors associated with SUDEP were male sex (for those >18 years) and subtherapeutic anticonvulsant medication levels (found in 55%). Where recorded, the majority of deaths happened in the person's usual residence (90%), were overnight (70%) and unwitnessed (87%), with the person found prone (74%), in or adjacent to their bed (49%) and with signs of proximate seizure (60%). A complete autopsy was undertaken for only 59% of cases, the majority in urban locations. This study provides support for an unwitnessed overnight seizure being a key factor in autopsy-confirmed SUDEP in Queensland.

SCN2A encephalopathy: A major cause of epilepsy of infancy with migrating focal seizures.

OBJECTIVE: De novo SCN2A mutations have recently been associated with severe infantile-onset epilepsies. Herein, we define the phenotypic spectrum of SCN2A encephalopathy. METHODS: Twelve patients with an SCN2A epileptic encephalopathy underwent electroclinical phenotyping. RESULTS: Patients were aged 0.7 to 22 years; 3 were deceased. Seizures commenced on day 1-4 in 8, week 2-6 in 2, and after 1 year in 2. Characteristic features included clusters of brief focal seizures with multiple hourly (9 patients), multiple daily (2), or multiple weekly (1) seizures, peaking at maximal frequency within 3 months of onset. Multifocal interictal epileptiform discharges were seen in all. Three of 12 patients had infantile spasms. The epileptic syndrome at presentation was epilepsy of infancy with migrating focal seizures (EIMFS) in 7 and Ohtahara syndrome in 2. Nine patients had improved seizure control with sodium channel blockers including supratherapeutic or high therapeutic phenytoin levels in 5. Eight had severe to profound developmental impairment. Other features included movement disorders (10), axial hypotonia (11) with intermittent or persistent appendicular spasticity, early handedness, and severe gastrointestinal symptoms. Mutations arose de novo in 11 patients; paternal DNA was unavailable in one. CONCLUSIONS: Review of our 12 and 34 other reported cases of SCN2A encephalopathy suggests 3 phenotypes: neonatal-infantile-onset groups with severe and intermediate outcomes, and a childhood-onset group. Here, we show that SCN2A is the second most common cause of EIMFS and, importantly, does not always have a poor developmental outcome. Sodium channel blockers, particularly phenytoin, may improve seizure control.

Phenotypic variation of TTC19-deficient mitochondrial complex III deficiency: a case report and literature review.

Isolated mitochondrial respiratory chain complex III deficiency has been described in a heterogeneous group of clinical presentations in children and adults. It has been associated with mutations in MT-CYB, the only mitochondrial DNA encoded subunit, as well as in nine nuclear genes described thus far: BCS1L, TTC19, UQCRB, UQCRQ, UQCRC2, CYC1, UQCC2, LYRM7, and UQCC3. BCS1L, TTC19, UQCC2, LYRM7, and UQCC3 are complex III assembly factors. We report on an 8-year-old girl born to consanguineous Iraqi parents presenting with slowly progressive encephalomyopathy, severe failure to thrive, significant delays in verbal and communicative skills and bilateral retinal cherry red spots on fundoscopy. SNP array identified multiple regions of homozygosity involving 7.5% of the genome. Mutations in the TTC19 gene are known to cause complex III deficiency and TTC19 was located within the regions of homozygosity. Sequencing of TTC19 revealed a homozygous nonsense mutation at exon 6 (c.937C > T; p.Q313X). We reviewed the phenotypes and genotypes of all 11 patients with TTC19 mutations leading to complex III deficiency (including our case). The consistent features noted are progressive neurodegeneration with Leigh-like brain MRI abnormalities. Significant variability was observed however with the age of symptom onset and rate of disease progression. The bilateral retinal cherry red spots and failure to thrive observed in our patient are unique features, which have not been described, in previously reported patients with TTC19 mutations. Interestingly, all reported TTC19 mutations are nonsense mutations. The severity of clinical manifestations however does not specifically correlate with the residual complex III enzyme activities.

Proximity of Axillary Nerve During Cortical Button Repair of Pectoralis Major Tendon Rupture.

BACKGROUND: Rupture of the pectoralis major (PM) tendon is a rare but severe injury. Several techniques have been described for PM fixation, including a transosseus technique, placing cortical buttons at the superior, middle and inferior PM tendon insertion points. The present cadaveric study investigates the proximity of the posterior branch of the axillary nerve to the drill positions for transosseus PM tendon repair. METHODS: Twelve cadaveric shoulders were used. The axillary nerve was marked during a preparatory dissection. Drills were passed through the humerus at the superior, middle and inferior insertions of the PM tendon and the drill bits were left in situ. The distance between these and each axillary nerve was measured using computed tomography. RESULTS: The superior drill position was in closest proximity to the axillary nerve (three-dimensional distance range 0-18.01 mm, mean 10.74 mm, 95% confidence interval 7.24 mm to 14.24 mm). The middle PM insertion point was also very close to the nerve. CONCLUSIONS: Caution should be used when performing bicortical drilling of the humerus, especially when drilling at the superior border of the PM insertion. We describe 'safe' and 'danger' zones for the positioning of cortical buttons through the humerus reflecting the risk posed to the axillary nerve.

A simple, safe and reliable surgical landmark for medial epicondylectomy.

BACKGROUND: Various surgical strategies have been described for the treatment of cubital tunnel syndrome, including medial epicondylectomy. This aims to decompress the ulnar nerve and allow a 'mini anterior transposition'. The major concern over medial epicondylectomy is the potential for postoperative iatrogenic valgus instability. METHODS: We utilized a surgical landmark for medial epicondylectomy based on the medial aspect of the ulnar nerve with the elbow in 90° of flexion in 12 cadaveric upper limbs. The size of the resultant fragment was measured and, subsequently, the medial collateral ligament was dissected and the elbow stressed to assess its integrity. RESULTS: This technique resulted in the excision of a fragment of mean width 8 mm (range 6 mm to 11 mm) and allowed the ulnar nerve to smoothly translate anteriorly in flexion. The anterior band of the ulnar collateral ligament was macroscopically preserved in all cases and there was no valgus instability. CONCLUSIONS: The medial border of the ulnar nerve is a simple, safe and reliable surgical landmark for medial epicondylectomy. This technique offers advantages over other described methods of assessing the location at which to perform a medial epicondylectomy.

High resolution chromosomal microarray in undiagnosed neurological disorders.

AIM: Despite advances in medical investigation, many children with neurological conditions remain without a diagnosis, although a genetic aetiology is often suspected. Chromosomal microarray (CMA) screens for copy number variants (CNVs) and long continuous stretches of homozygosity (LCSH) and may further enhance diagnostic yield. Although recent studies have identified pathogenic CNVs in intellectual disability, autism and epilepsy, the utility of CMA testing in a broader cohort of children with neurologic disorders has not been reported. METHODS: Two hundred fifteen patients with neurological conditions of unknown aetiology were seen over a 6-month period and were prospectively tested by CMA using high-resolution single nucleotide polymorphism (SNP) microarrays (Illumina HumanCytoSNP-12 v2.1 or Affymetrix 2.7M). RESULTS: Thirty of 215 (14%) patients tested had an abnormal CMA. Twenty-nine had CNVs (13%) and one (0.5%) a clinically significant stretch of homozygosity. Twenty (9.3%) had a CMA finding considered to be pathogenic or involved in susceptibility to the condition of interest, and 10 (4.7%) had findings of unknown significance. Their phenotypes included infantile spasms and other epilepsies, neuromuscular conditions, ataxia, movement disorders, microcephaly and malformations of cortical development. At least one third of patients did not meet national funding criteria for CMA at the time of presentation. CONCLUSIONS: CMA detected clinically significant abnormalities in a broad range of neurologic phenotypes of unknown aetiology. This test should be considered a first-tier investigation of children with neurologic disorders in whom the initial clinical assessment does not indicate a likely aetiology, especially those with severe epilepsies and neurologically abnormal neonates.