Is the Harris hip score system useful to study the outcome of total hip replacement?

Although the Harris hip score frequently is used to assess the outcome of total hip replacement, only a few minor validity tests have been presented. The aim of this study was to perform a validity test of the Harris hip score and to test its reliability. Two cohorts were studied. First, 58 patients who had undergone total hip replacement 2 to 10 years earlier were evaluated by an orthopaedic surgeon and an experienced physiotherapist using the Harris hip score. The patients also answered the Western Ontario and McMaster University Osteoarthritis Index and the Medical Outcomes Study 36-Item Short-Form Health Survey. Second, 1,056 patients answered the Western Ontario and McMaster University Osteoarthritis Index and the Medical Outcomes Study 36-Item Short-Form Health Survey questionnaires. The results were compared with those of a subcohort of 344 patients who were evaluated using the Harris hip score. The following items were tested: content validity, convergent and divergent construct validity, criterion validity, test and retest reliability, internal consistency reliability, and interobserver reliability. The Medical Outcomes Study 36-Item Short-Form Health Survey, Western Ontario and McMaster University Osteoarthritis Index, and the Harris hip score showed high validity and reliability. The Harris hip score can be used by a physician or a physiotherapist to study the clinical outcome of hip replacement.     

Does hip strength analysis explain the lower incidence of hip fracture in the People's Republic of China?

To explore whether there are ethnic differences in calculated hip strength that might explain the low incidence of hip fracture in China, we used Lunar DPX 'beta' version of hip strength analysis (HAS) and hip axis length (HAL) programs to compare hip geometry, calculated strength and densitometric values from Chinese subjects in Shenyang to those of Caucasian subjects in Oslo and Leuven participating in the European Prospective Osteoporosis Study (EPOS). Subjects were 210 Chinese and 403 Caucasian men and women aged 53-77 years. Parameters investigated included bone mineral density (BMD), bone mineral content (BMC), bone area (BA), cross-sectional moment of inertia (CSMI) and section modulus (both indicating strength and rigidity of the femoral neck), HAL, neck length (NL), neck diameter, tensile stress (Tstress) and compressive stress (Cstress) (indicating the stress in the femoral neck at its weakest cross section arising from walking or a standard fall, respectively), safety factor (SF, indicating the resistance to fracture for forces generated during walking) and fall index (FI, indicating the resistance to fracture from force generated during a fall in the greater trochanter). The Chinese men and women were significantly shorter and lighter than their Caucasian counterparts (P<0.01) and had significantly lower BMD, BMC and BA of the femoral neck (P<0.01). After adjusting for BA, weight and height, there was no significant ethnic difference in either gender in BMC. CSMI and section modulus were significantly lower, and HAL, NL and neck diameter were significantly shorter in the Chinese men and women (P<0.01). These differences all remained after adjusting for weight and height. There were no significant differences in Tstress, Cstress, SF and FI between ethnic groups in either gender. Most of the parameters of calculated hip strength in the Chinese subjects were similar to or poorer than those in the Caucasian subjects. There was no evidence to indicate that Shenyang Chinese have superior BMD or BMC or better calculated hip strength. The short HAL and NL of the population, however, could be an independent factor contributing to the low incidence of hip fracture.     

Does unilateral total hip arthroplasty improve pain and function in the non-operative hip joint?

European Journal of Orthopaedic Surgery & Traumatology - Some reports suggested that the status of the opposite-side hip affects clinical outcomes of unilateral total hip arthroplasty (THA) for...     

Does previous hip arthroscopy negatively influence the short term clinical result of total hip replacement?

Introduction  

The risk that hip preserving surgery may negatively influence the performance and outcome of subsequent total hip replacement (THR) remains a concern. The aim of this study was to identify any negative impact of previous hip arthroscopy on THR.     

New ��L value�� parameter simplifies and enhances hip ultrasound interpretation in the detection of developmental dysplasia of the hip

Purpose  

The purpose of this study was to simplify and enhance the ultrasound (US) analysis of the infant’s hip by introducing a novel parameter named “L value” into the widely used Graf method.     

Ipsilateral fractures of the pelvis and the femur – floating hip?

A consecutive series of 40 patients, who sustained 42 ipsilateral pelvic and femoral fractures, is reported. There were eight (26.6%) traumatic neurological deficits and three open femoral fractures. Two multiply injured patients died in the postraumatic period because of the severity of their injuries. No associated vascular injuries could be identified. All but two fractures of the femur, 8 of the 15 fractures of the pelvic ring and 17 of the 30 fractures of the acetabulum were treated by internal fixation. In 26 patients internal fixation was performed on both fracture components (in 17 patients this was done under the same period of anaesthesia). Postoperatively, a deep venous thrombosis in three patients, one deep wound infection and five (18.5%) iatrogenic neurological deficits had to be notified. In this series we could not identify any specific associated injuries and complications as known for the floating knee or the floating elbow. The term floating hip is inprecise and misleading, and its use is not recommended. The treatment of this fracture-combination follows the guidelines established for the individual lesions.     

Does hip implant positioning affect the peak external adduction moments of the healthy knees of subjects with total hip replacements?

After unilateral total hip replacement (THR) for hip osteoarthritis (OA), knee OA incidence or progression is common. The contralateral knee is at particular risk, and some have speculated that abnormal THR‐hip biomechanics contributes to this asymmetry. We investigated the relationships between operated‐hip joint geometry or gait variables and the peak external knee adduction moments—an indicator of knee OA risk—in 21 subjects with unilateral THRs. We found that the peak adduction moment was 14% higher on the contralateral versus the ipsilateral knee (p = 0.131). The best predictors of ipsilateral knee adduction moments were superior‐inferior joint center position and operated‐hip peak adduction moment (adj R² = 0.291, p = 0.017). The sole predictor of the contralateral knee adduction moment was the medial‐lateral hip center position (adj R² = 0.266, p = 0.010). A postoperative medial shift of the hip center was significantly correlated with a lower postoperative contralateral/ipsilateral knee adduction moment ratio (R = 0.462, p = 0.035). Based on these relationships, we concluded that implant positioning could influence the biomechanical risk of knee OA progression after THR. Although implant positioning decisions are necessarily driven by other factors, it may be appropriate to assess individual THR candidate's knee OA risk and adjust perioperative management accordingly. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1187–1194, 2013     

The management of intracapsular hip fractures in the 'young elderly' internal fixation or total hip replacement?

There is a lack of consensus about how to treat intracapsular hip fractures in the 'young elderly' (50-75 years). Evidence for older more mobile patients seems to point towards Internal Fixation (IF) for undisplaced fractures and Total Hip Replacement (THR) for displaced fractures. Radiographs of 263 patients from the Norfolk and Norwich University Hospital, who have suffered an intracapsular hip fracture between 2000-2009 were reviewed. The complication and mortality rates were noted. A Hip function questionnaire (Oxford hip score (OHS)) and Numeric pain score (NPS) were sent out to patients, then methods of treatment (IF and THR) were compared. In displaced fractures THR compared favourably to IF, OHS (16.0 vs. 20.0 p 0.029), NPS (2.0 vs. 4.0 p 0.007), complications (Odds Ratio (OR) 2.90; p 0.006) and death rate (OR 3.61; p 0.007). Although not statistically significant when stratified for age, the youngest age group (50-60) still achieved better function with a THR (13.0 vs. 18.0 ; p 0.129). There was little difference in the results for undisplaced fractures. This retrospective cross-sectional study showed IF is associated with a much higher complication rate than THR for patients who sustained a displaced hip fracture. THR also showed a better functional outcome and reduced pain. IF should be used in undisplaced fractures as there was no difference in functional outcome or complication rate. A large randomised controlled trial is needed to confirm these results.     

Hemiarthroplasty of the hip for fracture-what is the appropriate sized femoral head?

INTRODUCTION: Caliper measurement of the excised femoral head is a standard technique for determination of prosthetic head size during hemiarthroplasty for displaced femoral neck fractures. OBJECTIVES: To evaluate the accuracy of the caliper method of hemiarthroplasty head sizing by comparing it to the native joint congruency (JC) at the weight bearing surface. MATERIALS AND METHODS: The diameters of femoral heads in 10 cadaver hip joints were measured by using a caliper at the head equator. Cast moulds were prepared from both the acetabulum and the femoral head in each joint. Every mould's exact spherical diameter at the weight bearing region was measured by a computerised coordinate measuring machine (MNC B231 MITUTOYO). All specimens were coded to ensure that future examination was carried out in a blind manner. Native JC mismatch was determined by subtracting the diameter of the femoral cement mould from that of the acetabular one. Similarly, JC mismatch was calculated for the caliper measurements. RESULTS: The average native JC mismatch (0.36+/-0.29mm, range 0.03-0.82mm, median 0.29mm) was found significantly smaller (p=0.03) than following caliper measurements (0.72+/-0.37mm, range 0.37-1.46mm, median 0.6mm). Routine caliper measured downward size rounding enhanced (p=0.004) this mismatch (0.98+/-0.44mm, range 0.37-1.96mm, median 1.01mm), while upward rounding (0.48+/-0.46mm, range -0.06 to 1.15mm, median 0.41mm) helped mitigate this tendency. CONCLUSIONS: Caliper measurements tend to undersize the actual sphere diameter of the femoral head at the weight bearing region. Upward rounded prosthesis should be selected in order to compensate for this propensity.     

Developmental dysplasia of the hip: impact of sonographic newborn hip screening on the outcome of early treated decentered hip joints—a single center retrospective comparative cohort study based on Graf’s method of hip ultrasonography

Purpose/Background/Introduction  

The aim of this study was to retrospectively evaluate the impact of neonatal sonographic hip screening using Graf’s method for the management and outcome of orthopaedic treatment of decentered hip joints with developmental dysplasia of the hip (DDH), using three decades (1978–2007) of clinical information compiled in a medical database.     

Is the psoas a hip flexor in the active straight leg raise?

Psoas function is a topic of considerable relevance in sports and clinical science. However, the literature on psoas function is not sufficiently consistent. Questions are, amongst others, if during hip flexion the psoas always has the same function as the iliacus, and if the psoas affects the hip more than the lumbar spine. In the present study, 17 healthy women, 20–40 years, performed the active straight leg raise (ASLR), with the right or the left leg (“Side”), and without or with weight added above the ankle (“Condition”). Electromyographic (EMG) activity of psoas and iliacus were recorded with fine-wire electrodes, and of rectus femoris and adductor longus with surface electrodes, all on the right side. Movements of the leg were recorded with active markers and a camera system. During ASLR, the iliacus, rectus femoris, adductor longus and psoas were active ipsilaterally, but psoas was also active contralaterally. All muscles started to contract before movement onset, the iliacus, rectus femoris, and adductor longus largely at the same time, before the psoas. There was no significant difference between the amplitude or time of onset of ipsilateral and contralateral psoas EMG activity, nor was there a significant interaction between Side and Condition for the psoas. Although ipsilateral psoas activity is consistent with the psoas being a hip flexor, contralateral activity is not. The most simplest explanation of the pattern found is that the psoas is bilaterally recruited to stabilize the lumbar spine, probably in the frontal plane.     

Specific inferior dislocation of the hip： one case report

Hip joint dislocations are generally classified as anterior, posterior, and central dislocations. In 1970s, the anterior dislocation was divided into pubic type and obturator type.1 It is generally recognized that for anterior dislocation of the hip joint, the femoral head is located at anteriorinferior part of the acetabulum, characterized clinically as abduction, extorsion, slight flexion deformity, and longer limb than the opposite side. When posterior dislocation is present, the femoral head is located at posteriorsuperior part of the acetabulum and manifested clinically as flexion, adduction, intorsion, and shortening deformity.     

Infected total hip arthroplasty – the value of intraoperative histology

Intraoperative histology showed a sensitivity of 100% and a specificity of 98%. These results were better than those observed for the other tests evaluated. Our data provide evidence that intraoperative histology is useful tool in the diagnosis of infected total hip arthroplasty.     

Are there advances in the treatment of extracapsular hip fractures in the elderly?

While the rate of failure following hip fracture surgery for extracapsular hip fractures in the elderly is low, an incidence of implant cutout from the femoral head remains regardless of whether fixation is by sliding hip screw or intramedullary nail. In general, a well-executed osteosynthesis is the best assurance of a good outcome with few complications, and typically a less than ideal placement of the implant in the femoral head is the reason for cut-out and failure of the operation. It is clear that there is no difference in the incidence of complications or functional outcome between a sliding hip screw and an intramedullary nail for pertrochanteric fractures (AO/OTA 31-A1 and A2), while the implant of choice in the elderly for the true intertrochanteric fracture (AO/OTA 31-A3; reverse intertrochanteric) is a nail. However, what is less clear is whether there are newer ideas and/or implant designs that represent true advances in the treatment of extracapsular fractures in the elderly. The following review focuses on just this issue.     

Fractures of the hip: does the type of fall really affect the site of fracture?

The purpose of this study was to test accepted theories relating the characteristics of a fall to the anatomical site of hip fracture in the elderly. Twisting injuries are said to result in intracapsular fractures and falls directly onto the side are said to result in extracapsular fractures. 618 consecutive patients with a hip fracture were studied prospectively by being questioned with regard to the nature of their fall. After exclusions, 552 patients were left in the study. Of these, 324 patients sustained intracapsular fractures and 228 extracapsular fractures. More intracapsular fractures were associated with a fall onto the affected side than extracapsular fractures and rotation at the hip during the fall had a significant association with extracapsular fractures. In this study 84 per cent of all fractures occurred by falling directly onto the affected side. The clinical significance of this finding is that protective padding on the hip might be beneficial.     

Lack of evidence—the anti-stepwise introduction of metal-on-metal hip replacements

Background and purpose — Orthopedics and especially joint replacement surgery have had more than their fair share of unsuccessful innovations that have violated widely endorsed principles for the introduction of new surgical innovations. We aimed to investigate (1) the trends in the use of the Birmingham Hip Resurfacing (BHR), the ASR hip resurfacing (ASR HRA) and the ASR XL total hip replacement (ASR XL THR) system with very different market approval processes and (2) whether their use was corroborated by clinical trials published in the peer-reviewed literature.

Methods — The literature was searched for any clinical studies that reported outcomes of the BHR, ASR HRA and ASR XL THRs. Data from 7 national hip arthroplasty registers were collected and the number of annually implanted devices was matched to those reported in the literature.

Results — The cumulative number of implanted and published BHRs grew proportionally with a small lag. The growth of implanted BHRs started to decline at the same time as the ASR HR was introduced. With regard to ASR HRAs, the cumulative proportion of implanted hips and those included in the published studies grew disproportionately after the introduction of the ASR in 2003. For ASR XL THRs, the disproportionality is even higher.

Interpretation — The adoption of ASR hip replacements did not follow the proposed stepwise introduction of orthopedic implants. The adoption and use of any new implant should follow a strict guideline and algorithm even if the theoretical basis or the results of preclinical studies are excellent.     

Preoperative planning of total hip replacement using the TraumaCad™ system

Introduction  

Templating is now the standard approach for preoperative planning of total joint replacement and fracture fixation. The aim of this study was to assess the accuracy of new software, TraumaCad™, for preoperative planning for total hip replacement.