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

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

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

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

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

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

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). However, in the revision situation in general and in revision for recurrent dislocation specifically, it is important to have all options available including dual mobility 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 5% have been reported in the first two years 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 and where, a complex acetabular reconstruction that requires time for ingrowth before optimal implant bone stability to occur isn't present, dual mobility with 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 dual mobility with constraint 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 dual mobility 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 year average follow-up, 7% failure of device, 5% femoral loosening, 4% acetabular loosening. For Difficult Revisions: 101 hips, 10 year average follow-up, 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips, 3.6 year average follow-up (2–10 years), 2 of 31 failures

Aims

The aim of this study was to inform the epidemiology and treatment of slipped capital femoral epiphysis (SCFE).

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. However, in the revision situation, in general, and in revision for recurrent dislocation situations specifically, it is important to have all options available including dual mobility 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 5% have been reported in the first two years following revision surgery at institutions where high volumes of revision surgery are performed [Della Valle, Sporer, Paprosky unpublished data]. 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 and where, a complex acetabular reconstruction that requires time for ingrowth before optimal implant bone stability to occur isn't present, dual mobility with 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 dual mobility with constraint 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 dual mobility constrained liners: low demand patient, abductor muscle deficiency or soft tissue laxity, large outer diameter cups, multiple operations for instability, and instability with well-fixed shells that are adequately positioned. 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

Aims

The COVID-19 pandemic drastically affected elective orthopaedic services globally as routine orthopaedic activity was largely halted to combat this global threat. Our institution (University College London Hospital, UK) previously showed that during the first peak, a large proportion of patients were hesitant to be listed for their elective lower limb procedure. The aim of this study is to assess if there is a patient perception change towards having elective surgery now that we have passed the peak of the second wave of the pandemic.

Aims

Prior studies have identified that malseating of a modular dual mobility liner can occur, with previous reported incidences between 5.8% and 16.4%. The aim of this study was to determine the incidence of malseating in dual mobility implants at our institution, assess for risk factors for liner malseating, and investigate whether liner malseating has any impact on clinical outcomes after surgery.

Introduction. Through the paediatric LCP Hip plating system, the highly successful technique of the locking compression plate used in adult surgery, has been incorporated in a system dedicated to paediatrics. The purpose of this study was to review the outcome of the paediatric LCP Hip plate use in children, both with and without neuromuscular disease, for fixation of proximal femoral osteotomy for a variety of indications. Materials and methods. We retrospectively reviewed the notes and radiographs of all those children who have had Paediatric LCP Hip Plate for the fixation of proximal femoral osteotomy and proximal femur fractures in our institution, between October 2007 and July 2010, for their clinical progress, mobilization status, radiological healing and any complications. Results. Forty-three Paediatric LCP hip plates were used in forty patients for the fixation of proximal femoral osteotomies (n=40) and proximal femur fractures (n=3). The osteotomies were performed for a variety of indications including Perthes disease, DDH, Cerebral Palsy, Down's syndrome, coxa vara, Leg length discrepancy and previous failed treatment of SUFE. Twenty-five children were allowed touch to full weight bearing post operatively. Two were kept non-weight bearing for 6 weeks. The remaining 13 children were treated in hip spica due to simultaneous pelvic osteotomy or multilevel surgery for cerebral palsy. All osteotomies and fractures radiologically healed within 6 months (majority [n=40] within 3 months). There was no statistically significant difference (p = 0.45) in the neck shaft angle between the immediately postoperative and final x-rays after completion of bone healing. There were no implant related complications. Conclusion. The Paediatric LCP Hip Plate provides a stable and reliable fixation of the proximal femoral osteotomy performed for a variety of paediatric hip conditions in children with and without neuromuscular disease

Through the paediatric LCP Hip plating system (Synthes GmBH Eimattstrasse 3 CH- 4436 Oberdorff), the highly successful technique of the locking compression plate used in adult surgery, has been incorporated in a system dedicated to pediatrics. We are presenting the outcome of the paediatric LCP hip plating system used for a variety of indications in our institution. We retrospectively reviewed the notes and radiographs of all those children who have had Paediatric LCP Plate for the fixation of proximal femoral osteotomy and proximal femur fractures in our institution, between October 2007 and July 2010, for their clinical progress, mobilization status, radiological healing and any complications. Forty-three Paediatric LCP hip plates were used in forty patients (24 males and 13 females) for the fixation of proximal femoral osteotomies (n=40) and proximal femur fractures (n=3). The osteotomies were performed for a variety of indications including Perthes disease, developmental dysplasia of hip, Cerebral Palsy, Down's syndrome, coxa vara, Leg length discrepancy and previous failed treatment of Slipped Upper Femoral Epiphysis. Twenty-five children were allowed touch to full weight bearing post operatively. Two were kept non-weight bearing for 6 weeks. The remaining 13 children were treated in hip spica due to simultaneous pelvic osteotomy or multilevel surgery for cerebral palsy. All osteotomies and fractures radiologically healed within 6 months (majority [n=40] within 3 months). There was no statistically significant difference (p= 0.45) in the neck shaft angle between the immediately postoperative and final x-rays after completion of bone healing. Among the children treated without hip spica, 1 child suffered a periprosthetic fracture. Of the children treated in hip spica, 2 had pressure sores, 3 had osteoporotic distal femur fractures and 2 had posterior subluxations requiring further intervention. There were no implant related complications. The Paediatric LCP Hip Plate provides a stable and reliable fixation of the proximal femoral osteotomy performed for a variety of paediatric orthopaedic conditions

Patients with Neuromuscular disorders who have an arthritic hip joint present unique challenges. Due to inadequate bone stock, bony deformity and muscle imbalance there is a potentially increased risk of dislocation. These patients who have undergone conventional total hip replacement in the past, have been immobilised post-operatively in a hip spica to prevent post-op dislocation. Large heads are inherently more stable and adequately treat these patients, without the need for post-operative immobilisation. We present our experience with large head replacement in this group of patients. Eight patients, five with cerebral palsy, two with Down’s Syndrome and one with Cornelia de large Syndrome, who underwent total hip replacement with a large head prosthesis were reviewed. Their average age was 44.5 years and patients were followed up for maximum 51 months. Patients were assessed with respect to pre- and post-op pain, mobility and function. Hip scores have not been found to be useful in assessing these patients. Two Birmingham Surface replacements were used and six large heads on conventional stems, with large uncemented cups. In all patients there was improvement in pain and function. Four patients had improvement in their ambulatory status. In none did this worsen. Despite no post-operative immobilisation, there was only on dislocation. This was due to error in cup positioning, an error in the early learning curve. Despite the small numbers and short follow up, we feel that large head replacement is a viable alternative to conventional hip replacement in these difficult cases