Aims. To determine the normal values and usefulness of the C1/4 space available for spinal cord (SAC) ratio and C1 inclination angle, which are new radiological parameters for assessing atlantoaxial instability in children with Down syndrome. Patients and Methods. We recruited 272 children with Down syndrome (including 14 who underwent surgical treatment), and 141 children in the control group. All were aged between two and 11 years. The C1/4 SAC ratio, C1 inclination angle, atlas-dens interval (ADI), and SAC were measured in those with Down syndrome, and the C1/4 SAC ratio and C1 inclination angle were measured in the control group. Results. The mean C1/4 SAC ratio in those requiring surgery with Down syndrome, those with Down syndrome not requiring surgery and controls were 0.63 (standard deviation (. sd. ) 0.1), 1.15 (. sd . 0.13) and 1.29 (. sd. 0.14), respectively, and the mean C1 inclination angles were -3.1° (. sd.  10.7°), 15.8° (. sd. 7.3) and 17.2° (. sd. 7.3), in these three groups, respectively. The mean ADI and SAC in those with Down syndrome requiring surgery and those with Down syndrome not requiring surgery were 9.8 mm (. sd. 2.8) and 4.3 mm (. sd. 1.0), and 11.1 mm (. sd. 2.6) and 18.5 mm (. sd. 2.4), respectively. Conclusion. The normal values of the C1/4 SAC ratio and the C1 inclination angle were found to be about 1.2° and 15º, respectively. Cite this article: Bone Joint J 2016;98-B:1704–10

Significant hip osteoarthritis has been reported in 8–28% of patients with Down Syndrome. The prolonged life expectancy of these patients has allowed many of them to become disabled by their hip arthritis with the need for hip replacement. We have been able to perform a multi-center study evaluating total hip replacement in patients with Down Syndrome. Twenty patients (25 hips) with Down Syndrome underwent primary THA at a mean age of 35 years old with a mean 105-month follow-up. Cementless acetabular fixation with screws were used in all cases and all but one femoral component was cementless. Constrained liners were used in 8 cases to enhance stability. Five hips required revision surgery: two femoral components (one for periprosthetic fracture and one for aseptic loosening), two acetabular components (one for recurrent dislocation and one for wear with metallosis), and one hip required a two-stage revision for infection. Other than the hip revised for loosening, no other hip had radiographic evidence of loosening. The mean Harris Hip score improved from 42 points pre-operatively to 83 points at final follow-up. THA is a reliable surgical intervention in patients with Down Syndrome and symptomatic coxarthrosis. These patients and their families have been tremendously satisfied with this procedure. Strategies to prevent dislocation post THA are appropriate and need continued evaluation

Significant hip osteoarthritis has been reported in 8–28% of patients with Down Syndrome. The prolonged life expectancy of these patients has allowed many of them to become disabled by their hip arthritis with the need for hip replacement. We have been able to perform a multi-center study evaluating total hip replacement in patients with Down Syndrome. Twenty patients (25 hips) with Down Syndrome underwent primary THA at a mean age of 35 years old with a mean 105 month follow-up. Cementless acetabular fixation with screws were used in all cases and all but one femoral component was cementless. Constrained liners were used in 8 cases to enhance stability. Five hips required revision surgery: two femoral components (one for periprosthetic fracture and one for aseptic loosening), two acetabular components (one for recurrent dislocation and one for wear with metallosis), and one hip required a two-stage revision for infection. Other than the hip revised for loosening, no other hip had radiographic evidence of loosening. The mean Harris Hip score improved from 42 points preoperatively to 83 points at final follow-up. THA is a reliable surgical intervention in patients with Down Syndrome and symptomatic coxarthrosis. These patients and their families have been tremendously satisfied with this procedure

Down syndrome (DS), is a genetic disorder caused by a third copy of the 21st chromosome (Trisomy 21), featuring typical facial characteristics, growth delays and varying degrees of intellectual disability. Some degree of immune deficiency is variably present. Multiple orthopaedic conditions are associated, including stunted growth (90%), ligamentous laxity (90%), low muscle tone (80%), hand and foot deformities (60%), hip instability (30%), and spinal abnormalities including atlanto-axial instability (20%) and scoliosis. Hip disease severity varies and follows a variable time course. Rarely a child presents with DDH, but during the first 2 years the hips are characteristically stable but hypermobile with well-formed acetabulae. Spontaneous subluxation or dislocation after 2 presents with painless clicking, limping or giving way. Acute dislocation is associated with moderate pain, increased limp and reduced activity following minor trauma. Hips are reducible under anesthesia, but recurrence is common. Eventually concentric reduction becomes rarer and radiographic dysplasia develops. Pathology includes: a thin, weak fibrous capsule, moderate to severe femoral neck anteversion and a posterior superior acetabular rim deficiency. A number of femoral and acetabular osteotomies have been reported to treat the dysplasia, with acetabular redirection appearing to be most successful. However, surgery can be associated with a relatively high infection rate (20%). Additionally, symptomatic femoral head avascular necrosis can occur as a result of slipped capital femoral epiphysis. Untreated dysplasia patients can walk with a limp and little pain into the early twenties even with fixed dislocation. Pain and decreasing hip function is commonly seen as the patient enters adult life. Occasionally the hip instability begins after skeletal maturity. Total hip arthroplasty (THA) is the standard treatment when sufficient symptoms have developed. The clinical outcomes of 42 THAs in patients with Down syndrome were all successfully treated with standard components. The use of constrained liners to treat intra-operative instability occurred in eight hips and survival rates were noted between 81% and 100% at a mean follow-up of 105 months (6 – 292 months). A more recent study of 241 patients with Down syndrome and a matched 723-patient cohort from the Nationwide Inpatient Sample compared the incidence of peri-operative medical and surgical complications in those who underwent THA. Compared to matched controls, Down syndrome patients had an increased risk of complications: peri-operative (OR, 4.33; P<.001), medical (UTI & Pneumonia OR, 4.59; P<.001) and surgical (bleeding OR, 3.51; P<.001), Mean LOS was 26% longer (P<.001). While these patients can be challenging to treat, excellent surgical technique and selective use of acetabular constraint can reliably provide patients with excellent pain-relief and improved function. Pre-operative education of all clinical decision makers should also reinforce the increased risk of medical and surgical complications (wound hemorrhage), and lengths of stay compared to the general population

The best algorithm, measurements, and criteria for screening children with Down syndrome for upper cervical instability are controversial. Many authors have recommended obtaining flexion and extension views. We noted that patients who require surgical stabilization due to myelopathy or cord compression typically have grossly abnormal radiographic measurements on the neutral upright lateral cervical spine radiograph (NUL). This study was designed to determine whether a full series of cervical spine images including flexion/extension lateral radiographs (FEL) was important to avoid missing upper cervical instability. This is a retrospective evaluation of cervical spine images obtained between 2006 and 2012 for the purposes of “screening” children with Down syndrome for evidence of instability. The atlanto-dental interval, space available for cord, and basion axial interval were measured on all films. The Weisel-Rothman measurement was made in the FEL series. Clinical outcome of those with abnormal measurements were reviewed. Sensitivity, specificity, positive and negative predictive values of NUL and FEL x-rays for identifying clinically significant cervical spine instability were calculated. Two-hundred and forty cervical spine series in 213 patients with Down syndrome between the ages of four months and 25 years were reviewed. One hundred and seventy-two children had a NUL view, and 88 of these patients also had FEL views. Only one of 88 patients was found to have an abnormal ADI (≥6mm), SAC (≤14mm), or BAI (>12mm) on an FEL series that did not have an abnormal measurement on the NUL. This patient had no evidence of cord compression or myelopathy. Obtaining a single NUL x-ray is an efficient method for radiographic screening of cervical spine instability. Further evaluation may be required if abnormal measurements are identified on the NUL x-ray. We also propose new “normal” values for the common radiographic measurements used in assessing risk of cervical spine instability in patients with Down syndrome

The life expectancy of patients with Down syndrome has increased significantly in recent years. Hip abnormalities occur in children with this syndrome but little is known about their natural history in later life. In 65 adults with Down syndrome we found hip abnormalities in 28%, and this was statistically correlated with walking ability. A subgroup of 18 patients was followed by serial examination; this showed that hip instability occurred in adulthood and became worse with time. In some patients, hip instability started after skeletal maturity

There is an increased incidence of dislocation, dysplasia, slipped epiphysis, Perthes’ disease, and avascular necrosis leading to degenerative arthritis which occurs in up to 28% of Down's syndrome patients. As the life expectancy for patients with Down's syndrome has increased, so has the presence of hip disease. Hip replacement has been shown to have good results in this population. Special considerations include a high risk of postoperative dislocation and leg length inequality which often require large head THR or dual mobility type reconstruction to reduce these risks. Numerous spine deformities including scoliosis and C1-2 subluxation need to be taken into account-anesthesia consult

We treated eight dysplastic acetabula in six skeletally mature patients with Down’s syndrome by a modified Bernese periacetabular osteotomy. The mean age at the time of surgery was 16.5 years (12.8 to 28.5). Mean length of follow-up was five years (2 to 10.4). Pre-operatively the mean (Tönnis) acetabular angle was 28°, the centre-edge angle was −9°, and the extrusion index was 60%; post-operatively they were 3°, 37°, and 17%, respectively. Two patients with post-operative (Tönnis) acetabular angles > 10° developed subluxation post-operatively and required secondary varus derotation femoral osteotomies. Another patient developed a late labral tear which was treated arthroscopically. All eight hips remain clinically stable, and are either asymptomatic or symptomatically improved. These results suggest that the modified Bernese periacetabular osteotomy can be used successfully in the treatment of acetabular dysplasia in patients with Down’s syndrome

Hip osteoarthritis is prevalent in 8%–28% of patients with Down's Syndrome. Presence of disabling hip pain is increased along with prolonged life expectancy, suggesting total hip arthroplasty (THA). Seven consecutive patients (9 hips) with Down's syndrome had primary THA. Coxarthrosis was secondary to developmental hip dysplasia in 6 patients and slipped capital epiphysis in 1 patient. In 5 patients (7 hips) a previous hip surgery was performed. Average clinical and radiological follow up was 9.9 ± 6.4 years (range 2–22.5, median 9.3). Average age of patients at THA was 34.8 ± 7.5 years (range 25–47, median 35.4). In 2 patients (3 hips) a trochanteric slide was used for the surgical approach, while a lateral transgluteal approach was used in the remaining patients. One way ANOVA test was used to compare Harris Hip Scores (HHS) at post-operative follow-up. HHS improved significantly (p=0.008) improved from 4.1 ± 15.1 (range 18.5–65, median 45) to 84.3 ± 7.7 (range 70–93, median 85.8 at 4 year follow up. HHS (average 70.9 ± 6.2, range 66.5–80, median 68) remained essentially unchanged (p=0.43) at 8 year follow-up. Two patients required revision arthroplasty for stem loosening at 6 and 16 years post THA, respectively. The first patient is 7 years post revision and ambulates without aids. The second patient is 6.1 years post revision and ambulates with a walker. Six of the THAs required a constrained liner. No dislocations or deep infections were encountered. THA is reliable surgical intervention in patients with Down's Syndrome and symptomatic coxarthrosis

Down’s syndrome is associated with a number of musculoskeletal abnormalities, some of which predispose patients to early symptomatic arthritis of the hip. The purpose of the present study was to review the general and hip-specific factors potentially compromising total hip replacement (THR) in patients with Down’s syndrome, as well as to summarise both the surgical techniques that may anticipate the potential adverse impact of these factors and the clinical results reported to date. A search of the literature was performed, and the findings further informed by the authors’ clinical experience, as well as that of the hip replacement in Down Syndrome study group. The general factors identified include a high incidence of ligamentous laxity, as well as associated muscle hypotonia and gait abnormalities. Hip-specific factors include: a high incidence of hip dysplasia, as well as a number of other acetabular, femoral and combined femoroacetabular anatomical variations. Four studies encompassing 42 hips, which reported the clinical outcomes of THR in patients with Down’s syndrome, were identified. All patients were successfully treated with standard acetabular and femoral components. The use of supplementary acetabular screw fixation to enhance component stability was frequently reported. The use of constrained liners to treat intra-operative instability occurred in eight hips. Survival rates of between 81% and 100% at a mean follow-up of 105 months (6 to 292) are encouraging. Overall, while THR in patients with Down’s syndrome does present some unique challenges, the overall clinical results are good, providing these patients with reliable pain relief and good function. Cite this article: Bone Joint J 2013;95-B, Supple A:41–5

Hip disease occurs in between 8% and 28% of patients with Down’s syndrome, many of whom develop disabling pain. We have carried out total hip replacement in six adult patients (9 hips) with severe arthritis of the hip. The mean follow-up was 7.75 years (2 to 14). At the latest review, all had relief of pain and full hip function. Increasing longevity and a high incidence of hip disease in these patients suggest a greater role for total hip arthroplasty in the future

The purpose of this study was to describe the clinical course of patients with Down's syndrome (DS) and congentital talipes equinovarus (CTEV) treated with the Ponseti regimen. The members of the United Kingdom Ponseti Users Group were contacted to provide details of patients with DS and CTEV, whom they had treated using the Ponseti regimen. Nine patients (13 feet: 7 right, 6 left) were identified, and the case notes were reviewed. Six patients were male, 3 female. In all but one case, the DS was diagnosed postnatally. Co-morbidites included atrioventricular septal defect, hearing deficiencies and plagiocephaly. The initial mean Pirani score was 4.5 (range 3.0 to 6.0). Casting was commenced at a mean of 25 days (range 12–84 days). The mean number of casts required was 7 (range 3 to 12), taking a mean of 6.5 weeks (range 3–12) to achieve correction. 6 of the 13 feet (46%) required a tendoachilles tenotomy, and 2 of 13 (15%) required re-casting. No patients have required a tibialis anterior transfer, soft tissue releases or bony procedures, at a mean follow up of 44 months (9–65 months). The results of the Ponseti regimen have not been described in patients with DS. From this small series, we can conclude that all patients responded to the regime. A tendoachilles tenotomy was required in just under half, and further casting was required in only 15% of the treated feet. No patient has required further surgery. The tenotomy rate is lower than in most series, but otherwise, the results are comparable to those for idiopathic CTEV for which the Ponseti regimen has become the gold standard. Parents of children with DS can be reassured that in the short term their feet will respond well to Ponseti treatment

Dysplasia of the hip, hypotonia, osteopenia, ligamentous laxity, and mental retardation increase the complexity of performing and managing patients with Down syndrome who require total hip replacement (THR). We identified 14 patients (six males, eight females, 21 hips) with Down syndrome and degenerative disease of the hip who underwent THR, with a minimum follow-up of two years from 1969 to 2009. In seven patients, bilateral THRs were performed while the rest had unilateral THRs. The mean clinical follow-up was 5.8 years (standard deviation (. sd. ) 4.7; 2 to 17). The mean Harris hip score was 37.9 points (. sd. 7.8) pre-operatively and increased to 89.2 (. sd. 12.3) at final follow-up (p = 1x10. -9. ). No patient suffered a post-operative dislocation. In three patients, four hips had revision THR for aseptic loosening at a mean follow-up of 7.7 years (. sd. 6.3; 3 to 17). This rate of revision THR was higher than expected. Our patients with Down syndrome benefitted clinically from THR at mid-term follow-up. Cite this article: Bone Joint J 2014;96-B:1455–8

Introduction and Aims: The aim of this paper is to review C1-C2 facet screw use in paediatric patients and to demonstrate that the technique plays an important role in patients with underlying anatomic abnormalities, which are common in children with cervical instability. Method: A chart review was conducted of all patients managed with C1-C2 facet screws from January 1, 1996 until July 30, 2003 present in the case database. All radiographs were obtained and reviewed. Post-operative and follow-up films were assessed for acceptable screw position and evidence of fusion. Results: C1-C2 facet screws were utilised in nine patients at British Columbia’s Children’s Hospital. The youngest patient treated was five years of age with a mean age for the group of 12. The group consisted of three Down syndrome patients and six with Os Odontoidium, two of which failed previous C1-C2 fusion. Two patients presented with an acute spinal cord injury. Pre-operative CT or MR imaging was used in all patients. Screw placement was unacceptable in one case. Post-operative Halo immobilisation was used in seven patients. Post-operative complications included one wound infection and four halo pin infections requiring treatment. No patients have required surgery at a mean follow-up of four years. C1-C2 facet screws are an important adjunct in a paediatric spine practice. This technique has a great advantage in Down syndrome patients who have a high rate of pseudoarthosis because of: ligamentous laxity, non-compliance with immobilisation and a high incidence of congenital deformities such as os odontoidium and incomplete posterior arch of C1. Conclusion: C1-C2 facet screws can be safely used in young children. The screws allow for fixation in the absence of an intact posterior arch. The technique has a great advantage in Down syndrome patients who have a high rate of pseudoarthosis due to congenital deformities, ligamentous laxity and non-compliance with immobilisation

The February 2015 Hip & Pelvis Roundup. 360 . looks at: Hip arthroplasty in Down syndrome; Bulk femoral autograft successful in acetabular reconstruction; Arthroplasty follow-up: is the internet the solution?; Total hip arthroplasty following acetabular fracture; Salvage arthroplasty following failed hip internal fixation; Bone banking sensible financially and clinically; Allogenic blood transfusion in arthroplasty

Background: Congenital dislocation of the patella can cause significant functional disability and is often associated with limb deformity in childhood. Two types or clinical manifestations of this condition have been previously described, namely the fixed lateral dislocation and the habitual or obligatory dislocation of the patella. Few surgical procedures have been suggested for the treatment of the complex condition. Objective: We reviewed our surgical approach in ten knees (seven children) with both types of patellar dislocation, and evaluated the clinical and functional outcomes. Methods: All our patients underwent an extensive sub-periosteal mobilization of the extensor mechanism from the lateral side of the thigh combined anteriorly with plication of the medial patellar retinaculum. This procedure was supplemented by medialization of half of patellar tendon in the skeletally immature patients, and by tibial tuberosity transfer that was performed in one skeletally mature patient. Results: In six children, patellar dislocation was a part of a diagnosed syndrome, namely Down (3 patients), Larsen (1 patient), Rubinstein-Taybi (1 patient) and fibular hemimelia (1 patient). Six knees had fixed type and four (all Down syndrome) had obligatory type of patellar dislocation. Average age at surgery was 9.5 years (range 3.5–14) and the mean follow-up period was 19 months (range 7–33). There was no recurrence during the follow-up period. Two children with Down syndrome, who had flexion contraction and were non-ambulatory, began to walk three months and five months after the surgery. A significant resolution of the valgus deformities was obtained in the operated knees. Two complications were recorded, an undisplaced supracondylar fracture following removal of plastic cast and transitory peroneal nerve palsy. Conclusions: Abnormal anatomical muscular and bony changes, soft tissue structural changes and limb alignment contribute to patellar dislocation and to subsequent clinical deterioration and deformity progression. Our surgical intervention aimed to realign the extensor mechanism and was effective in treating both types of congenital dislocation of the patella. Based on our experience, the long-standing habitual dislocation is accompanied by changes in the extensor mechanism of the knee that are similar to those occurring in the fixed patellar dislocation and therefore should be addressed surgically in a similar manner

We believe that soft tissue release and articulated hip distraction distinguishes itself in the short term as a good salvage procedure for late onset severe Perthes disease of the hip. Our series is made of 10 patients with late onset Perthes disease. All 10 patients were above 9 years of age at diagnosis (average = 11 years). There were 7 boys and 3 girls in the series. All patients had significant limp and pain with positive Trendelenburg sign. All patients used crutches or wheelchairs and had symptoms for a period of 0.5 to 3 years before the operation; all hips had limited ROM. Two patients had previous soft tissue release. There were 2 children with Down syndrome and 1 child had Gleophysic Dysplasia. On preoperative radiographs, 8 patients had a saddle shape subluxating femoral head with hinge abduction and 2 subluxations only. Nine hips were graded Catterall IV and Herring C and 1 hip Catterall III Herring B. There were at least 3 and mostly 4 Catterall prognostic risk signs for these hips. All patients had a broken Shenton line, increased medial joint distance and low Epiphyseal index before surgery. After adductor and ileopsoas release an orthofix hinged apparatus for distraction is applied to the hip. The distraction continues until overcorrecting of Shenton line achieved. The external fixator is left in place for 4–5 months while in the apparatus flexion and extension of the hip is possible and encouraged. The follow-up ranged from 0.5 to 3 years. At last follow-up all patients were walking freely with improved hip ROM. All patients resumed daily ambulatory status and 2 were involved in regular sports. Latest radiographs showed that the saddle shape disappeared in 7 of 8 hips, in all patients hip subluxation decreased as measured by medial joint distance and Shenton line was corrected to between 0.6 mm. The Epiphysis index and joint congruency improved in most cases. The level of satisfaction from the operation was very high for all patients and their parents. Drawing of final conclusion will be possible only after assessing the long-term results

The advent of modular porous metal augments has ushered in a new form of treatment for acetabular bone loss. The function of an augment can be seen as reducing the size of a defect or reconstituting the anterosuperior/posteroinferior columns and/or allowing supplementary fixation. Depending on the function of the augment, the surgeon can decide on the sequence of introduction of the hemispherical shell, before or after the augment. Augments should always, however, be used with cement to form a unit with the acetabular component. Given their versatility, augments also allow the use of a hemispherical shell in a position that restores the centre of rotation and biomechanics of the hip. Progressive shedding or the appearance of metal debris is a particular finding with augments and, with other radiological signs of failure, should be recognized on serial radiographs. Mid- to long-term outcomes in studies reporting the use of augments with hemispherical shells in revision total hip arthroplasty have shown rates of survival of > 90%. However, a higher risk of failure has been reported when augments have been used for patients with chronic pelvic discontinuity.

Cite this article: Bone Joint J 2024;106-B(4):312–318.

Aims

The aims of this study were to characterize the incidence and risk factors associated with stress fractures following periacetabular osteotomy, and to determine their effect on osteotomy union.

In primary total hip replacements there are numerous options available for providing hip stability in difficult situations (i.e. Down's syndrome, Parkinson's disease). We have considered constrained liners in some of these cases. However, in the revision situation in general and in revision for recurrent dislocation situation specifically it is important to have all options available including tripolar constrained liners in order to optimise the potential for hip stability as well as function of the arthroplasty. Even with the newer options available dislocation rates of higher than 10–15% have been reported following revision surgery at institutions where high volumes of revision surgery are performed. Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups revision cases will always have more potential for dislocation. In these situations in the lower demand patient, constraint has provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate- term follow-up. Hence in these situations tripolar constrained liners remains the option we utilise. We are also confident in using this device in cases with instability or laxity where there is a secure well- positioned acetabular shell. We cement a dual mobility constrained liner in these situations using the technique described below. Present indication for tripolar constrained liners: low demand patient, large outer diameter cups, instability with well-fixed shells that are adequately positioned, abductor muscle deficiency or soft tissue laxity, multiple operations for instability. Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle. Results. Constrained Dual Mobility Liner. For Dislocation: 56 Hips, 10 yr average f/u, 7% failure of device, 5% femoral loosening, 4% acetabular loosening. For Difficult Revisions:101 hips, 10 yr average f/u, 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips, 3.6 yr average f/u (2–10 years), 2 of 31 failures