We investigated the extent to which improved balance relative to pain relief correlates with the success of total knee replacement (TKR). A total of 81 patients were recruited to the study: 16 men (19.8%) and 65 women (80.2%). Of these, 62 patients (10 men, 52 women) with a mean age of 73 (57 to 83) underwent static and dynamic assessment of balance pre-operatively and one year post-operatively. The parameters of balance were quantified using commercially available and validated equipment. Motor function and self-reported outcome were also assessed.

There was a significant improvement in dynamic balance (p < 0.001) one year after TKR, and better balance correlated with improved mobility, functional balance and increased health-related quality of life. As it seems that balance, and not only pain relief, influences the success of TKR, balance skills should be better addressed during the post-operative rehabilitation of patients who undergo TKR.

Many orthopedic departments provide their patients with implant-specific identification cards. These cards should assist patients in various security checks and while undergoing revision surgery, especially if performed far from the primary hospital. This retrospective study was performed to evaluate patients’ use of these cards.

In our department, each arthroplasty patient receives an implant-specific identification card. A phone survey was conducted among two groups of consecutive patients who underwent a lower limb arthroplasty – first group consisted of 108 patients operated a year earlier and second – 120 patients operated 3 years earlier. In the first group, 97 patients (90%) replied and in the second group – 83 patients (69%). The patients were asked the following: whether they received the card, where they keep it, what do they know about its purposes, and have they used the card for security or medical reasons.

17 patients (18%) in one-year group and 18 patients (22%) in three-years group didn’t remember the card. The rest of the patients knew the location of the card, but most of them (80% in one-year group and 72%in three-years group) knew only about the security usage of the card and not about the medical one. Many patients complained that they were not given adequate explanations about the card.

Implant-specific identification cards have significant value for arthroplasty patients. However, patients use them mostly for security checks. The medical usage of this card should be explained when they receive it, so the patients can assist their surgeons while performing a revision surgery.

Introduction: The postoperative rehabilitation after a primary knee arthroplasty may be infiuenced by a variety of factors. Nevertheless, only a few studies evaluated the effect of various factors on patients’ short-term outcome. This prospective study was conducted to evaluate the effect of different factors on patients’ function six weeks after the surgery.

Patients and methods. We prospectively recruited 107 patients with osteoarthritis who underwent an uncomplicated total knee arthroplasty, using the same prosthesis and operative technique. Following variables were collected before and after the surgery: age, BMI, visual analogue pain score at rest and during activity, preoperative range of knee motion, involvement of other joints, comorbidities (Katz index), self assessed health status, admission and discharge hemoglobin levels, amount of blood transfusions and intensity of postoperative physiotherapy.

In order to quantify patients’ level of functioning, we used a timed up and go test (TUG) and the Oxford knee score that were collected before and after the surgery. To eliminate the infiuence of postoperative weakness on rehabilitation, hand grip measurements were performed as well. A multivariate regression analysis was performed to examine the infiuence of different peri-operative variables on the outcome measures. Adjusted R2 was measured to estimate the explanatory power of infiuence of these variables.

Results: There was no significant difference between preoperative and postoperative hand grip force measurements, indicating that the general strength of the patients did not deteriorate. A postoperative TUG was worse with higher preoperative TUG and higher rest pain score (adjusted R2=0.53). The amount of improvement in TUG was better only with lower rest pain score (adjusted R2=0.06). A postoperative Oxford hip score was better only with lower rest pain score (adjusted R2=0.30). The amount of improvement in the Oxford score was not infiuenced by any of the variables (adjusted R2=0.01). Only significant infiuences (p< 0.05) are mentioned.

Discussion: Most of preoperative and postoperative measured variables, including age, BMI, comorbidities, hemoglobin concentration and amount of physiotherapy had no significant effect on patient’s functional status after uncomplicated knee arthroplasty. Only the pain at rest had infiuence on the functional result. These results suggest that patient personality has a most significant effect on knee arthroplasty results, either through pain perception or otherwise.

Introduction: Publication rate from orthopedic conferences is reported to be as high as 58% (AAHKS). However, national orthopedic meeting, is a stage where many local papers are presented that do not necessary have an interest to the broad orthopedic forums and thus are not published. We conducted this study to examine the publication rate of papers presented in the National Orthopaedic Association meetings after 5 and 10 years.

Materials and Methods: We reviewed abstract books of National Orthopaedic Association meetings in the year 2003 and years 1998–1999. All invited and plenary lectures were excluded. Pubmed search was performed using authors’ names to find similar publications. The similarity was then rechecked by another author. The specific orthopedic subspeciality was noted; in some cases the same presentation could be classified in two different subspecialities.

Results: 160 works were presented in the years 1998–1999 and 36 of them were published (22.5%). In 2003 27 out of 105 presented works were published (25.7%). In different subspecialities, the publication rate was 48% for pediatric orthopedics, 45% for foot and ankle, 33% for hand, 29% for shoulder and elbow, 27% for basic research, 22% for spine, 21% for trauma, 19% for oncology, 18% for hip and knee and 10% for sports medicine. 14 published papers (22%) were from international institutions. Six papers were published before the presentation at the meeting (two at each year).

Conclusion: The publication rate of papers presented at the National Orthopedic Association meetings is around 24% and most are published at the first five years. However, many of these published papers are not from international institutions. More effort should be put both in better selection of presentations and in supporting young researchers for bringing their work to publication.

Introduction: Distal radius fracture in postmenopausal women is often the first clinical symptom of osteoporosis. Both patients and family physicians are generally unaware of this. It is estimated that only 15–25% of postmenopausal women with a distal radius fracture are further referred to perform a bone density examination. The purpose of the current study was to examine whether a simple intervention by the hospital staff would increase the percentage of patients that undergo diagnostic workup after suffering a fracture in the distal radius.

Patients and Methods: This prospective study included 99 women aged 48–70 seen in the emergency room for a distal radius fracture. All patients were contacted 6–8 weeks after the ER visit and asked as to whether they had received an explanation from the hospital or from the family physician about the significance of the fracture for osteoporosis, and whether they had been referred to a bone density examination. 49 patients served as a control group. The intervention group (50 patients) were then given a detailed explanation regarding the implications of the fracture for osteoporosis, and in addition, received a letter with an explanatory leaflet and an appeal to the family physician with recommendations and an article on osteoporosis.

An additional telephone survey was conducted 6–8 weeks after the first conversation to assess the influence of the intervention.

Results: 15 patients in the intervention group and 14 patients in the control group were lost to follow up or were already treated for osteoporosis before the fracture. At the second phone call 24 patients (72.7%) from the intervention group had contacted their family physician after the intervention, compared to 8 patients (22.9%) in the control group (p=0.0003). 14 patients (42.4%) from this group underwent a bone density examination, compared to 5 patients (14.3%) in the control group (p=0.0003).

Conclusion: It is of great importance that patients understand the connection between the current problem for which they are receiving treatment in the emergency setting and the possibility that there is an underlying cause. In addition the connection between the hospital and the community is very important in increasing the number of patients diagnosed and treated.

Introduction. Back pain is one of the most common health problems in the industrialized world. Although using insoles appears to be common clinical practice, there is no hard data to support its effectiveness in prevention of low back pain. As a part of a Cochrane review, we conducted a literature search to determine the effectiveness of shoe insoles in the prevention and treatment of non-specific back pain compared to placebo, no intervention, or other interventions.

Materials and methods. We identified relevant clinical trials by searching The Cochrane Back Group Specialized Registry, The Cochrane Central Register, MED-LINE, EMBASE and CINAHL. All retrieved abstracts were blinded and were assessed by two independent investigators who decided on their inclusion. All these were again assessed by two different independent investigators, using the eleven items reflecting internal validity recommended by the Cochrane Back Review Group. A trial was considered to be of high quality if six or more out of eleven criteria were met.

Results. Our search found a total of 324 references. 8 papers, meeting the predetermined inclusion criteria, were retrieved of which six were found suitable for final evaluation. The clinical trials described in the papers included more than 2400 patients who used insoles for 3–5 months. Two articles with 199 patients demonstrated improvement in low back pain, while three larger studies found no difference between using insoles or no using insoles.

Discussion. There is no evidence for recommending the use of insoles for prevention of back pain. Additional high quality trials must be done to determine if they are effective in the treatment of low-back pain.

Introduction. Ankle and midfoot injuries are one of the most common orthopaedic complaints, both in the general medicine and the orthopedic practice. The percentage of fractures among these is small, however many of them will undergo an xray. Ottawa ankle rules are clinical guidelines developed for the use of radiography in these cases. This aim of this prospective study was to examine these rules’ implementation in the Israeli emergency medicine department and our ability both to predict a fracture and to reduce the amount of unnecessary xrays.

Materials and methods. 92 consecutive patients with ankle injuries attending our emergency medicine department were divided in two groups. Study group included 32 patients who arrived during the morning shift and were examined by an internal medicine specialist according to the Ottawa ankle rules. Patients discharged without an xray were followed in the clinic or by telephone communication. Control group included 60 patients who were examined during the evening and night shifts by orthopedic residents unaware of the study.

The mean age in the study group was 24 years and in the control group – 26 years. There was good acceptance of the study in patients of the study group. Only 2 of them insisted on the xrays and were excluded from the study. Rest 30 patients were followed as described.

Results. 9 patients (30%) in the study group underwent an xray as opposed to 55 patients (92%) in the control group (p< 0.001). There was one fracture diagnosed in each group. In the study group, no fractures were found later in patients discharged without an xray. The mean time spent in the emergency department was 58 minutes in the study group and 98 minutes in the control group (p< 0.002).

Discussion. The Ottawa ankle rules were developed as a simple “yes/no” decision tool as to whether to xray the ankle. In our emergency department, these rules were proved both accurate and safe. They can be effectively used by professionals not trained in trauma. It can save radiation and patient waiting time without jeopardizing the treatment.

Osteoporosis is a very common disease in the elderly, generally undertreated. Hip fracture is often the first clinical painful symptom of osteoporosis. It would seem that hip fracture should be a good opportunity to convince the patient of the importance of osteoporosis treatment. We conducted this study to check whether a simple intervention improved the compliance of osteoporosis treatment.

100 consecutive elderly patients with osteoporotic hip fracture received, during postoperative hospital stay, a 5–10 minutes long explanation about osteoporosis, its sequelae, treatment options and their effectiveness in further fracture prevention. Patients received an explanatory brochure and a letter to family physician that included a recent article on fracture rate reduction with osteoporosis treatment. Compliance was examined by telephone survey 3 and 6 months postoperatively.

100 consecutive patients with similar demographic characteristics who were treated for hip fracture prior to intervention served as a historical control. All patients received a recommendation for osteoporosis treatment in the discharge letter.

At follow up, 40% of patients in the study group were receiving biphosphonates, as opposed to 20% in the control group (p< 0.01). 77% of control patients received no treatment for osteoporosis compared to 37% of patients after intervention (p< 0.01).

Giving the patient a short explanation about osteoporosis combined with a letter to family physician, resulted in a significant improvement in their compliance The orthopaedic surgeon, who treats the patient at the first painful symptom of osteoporosis, has an excellent opportunity to improve patient’s understanding of the disease and her or his compliance to treatment.

Introduction: The common belief is that navigation-assisted TKR improves the surgical accuracy and reduces outliers, albeit increasing the operating time. We conducted a detailed study of the published studies with four main criteria:

Reduction of outliers in the placement of implants.

Methods: We performed a computerized search of the PubMed repository and a manual search of the proceedings of the International Society for Computer Assisted Orthopaedic Surgery (CAOS, 2001–05) to include all studies that presented clinical data of the results of this procedure. A total of 139 clinical studies were found, a total of 7,158 patients who underwent navigation-assisted TKR.

Results: Of the 139 studies, 39 studies presented data showing a reduction of outliers of the post-operative mechanical axis in the 180±3° range. 2,130 out of 2,401 (89%) patients operated with navigation were within this range. 27 out of the 39 studies compared the postoperative alignment of the navigated technique to that of the non-navigated technique. In the non-navigated technique, only 1,325 out of 1,880 (71%) patients were in that range, close to the published 74–75% for conventional TKR studies.

Regarding the operating time with navigation, 32 studies report an average increase of 21 min. (range 6– 48 min.), or about 20% than conventional TKR.

One of the perceived benefits of using extramedullary jigs in navigation-assisted TKR is thought to be reduction of blood loss. However, of the 15 studies that address this issue, 10 (67%) found no significant difference compared to the conventional technique. Regarding post-operative functional and/or pain scoring, 12 (80%) out of 15 studies found no statistically significant differences between navigated and non-navigated techniques.

Conclusions: The published clinical data so far shows that navigated-assisted TKR provides good alignment of the implants and a reduction of outliers from one in four to at most one in ten at the expense of 15–20 min. (about 20%) increase in operating time. No significant advantage was found for blood loss or functional/pain scoring. From a public health viewpoint, the increased cost of the navigated procedure may very well be compensated by the reduction of future revisions.

Introduction: Currently patients who had undergone lower limb arthroplasty are discharged a few days after surgery, at which stage they still need anticoagulation treatment. The transition from hospital to the community is a sensitive period and is susceptible to mistakes and misunderstandings. Patients may underestimate the importance of the continuing treatment and their inconvenience to self-administrate subcutaneous treatment might decrease their compliance. The purpose of this prospective cohort study was to investigate the continuity of the treatment with subcutaneous low molecular weight heparin at the transition period from the hospital to the community.

Materials and Methods: 209 consecutive consenting patients who had undergone lower limb arthroplasty were recruited. Ten were excluded from the study since they were subscribed oral anticoagulation; 4 patients developed pulmonary embolism and were not included, and 8 patients were lost to follow up. 187 patients were followed weekly by phone and were asked about their adherence to the daily treatment, about clinical signs suggesting a thromboembolic event and whether they sought medical assistance. Three months later there was another clinical follow up.

Results: Of the 187 patients, 174 (93%; 95% CI 88.9% < p < 96.4%) were compliant. The percentage of doctor visits by TKR patients was statistically significantly higher, (p=0.007) than by THR patients. There was no significant difference in the compliance of patients who live with their families and patients who live alone. Patients with 0–6 years of education tend to search medical advice statistically significantly more (p=0.004) than patients with more than 7 years of education.

Discussion: The rate of compliance to anticoagulation treatment with subcutaneous low molecular weight heparin was encouraging. It demonstrates that the patients understand the necessity and importance of the treatment.

Introduction: Ankle and midfoot injuries are one of the most common orthopaedic complaints, both in the general medicine and the orthopedic practice. The percentage of fractures among these is small, however many of them will undergo an x-ray. Ottawa ankle rules are clinical guidelines developed for the use of radiography in these cases. This aim of this prospective study was to examine these rules’ implementation in the Israeli emergency medicine department and our ability both to predict a fracture and to reduce the amount of unnecessary x-rays.

Materials and Methods: Ninty-two consecutive patients with ankle injuries attending our emergency medicine department were divided in two groups. Study group included 32 patients who arrived during the morning shift and were examined by an internal medicine specialist according to the Ottawa ankle rules. Patients discharged without an x-ray were followed in the clinic or by telephone communication. Control group included 60 patients who were examined during the evening and night shifts by orthopedic residents unaware of the study.

The mean age in the study group was 24 years and in the control group – 26 years. There was good acceptance of the study in patients of the study group. Only 2 of them insisted on the xrays and were excluded from the study. Rest 30 patients were followed as described.

Results: Nine patients (30%) in the study group underwent an x-ray as opposed to 55 patients (92%) in the control group (p< 0.001). There was one fracture diagnosed in each group. In the study group, no fractures were found later in patients discharged without an x-ray. The mean time spent in the emergency department was 58 minutes in the study group and 98 minutes in the control group (p< 0.002).

Discussion: The Ottawa ankle rules were developed as a simple “yes/no” decision tool as to whether to x-ray the ankle. In our emergency department, these rules were proved both accurate and safe. They can be effectively used by professionals not trained in trauma. It can save radiation and patient waiting time without jeopardizing the treatment.

Introduction: Osteolysis is a significant problem associated with hip replacement. In the early stages of osteolysis, when the implant is still stable, formal revision is technically demanding and may result in signififant bone loss. A recently described technique for acetabular component revision addresses osteolysis, retaining the acetabular cup and cementing a new polyethylene liner.

Materials and Methods: Between January 2000 and December 2003, 29 liner cementation revisions in 27 patients were performed. The mean age was 61 years (range 37–77), the mean time elapsed after the original surgery was 6.7 years (3–14). 23 of the hips (79%) were ABG (Howmedica). Only 20 (69%) of the patients were clinically symptomatic. At surgery the polyethylene was removed and osteolytic cysts were debrided. Then, the metal acetabular component was tested for stability. Obviously, only stable metal implants were not revised. The cysts were filled with bone graft or bone substitute and a new polyethylene liner was cemented in with methylmetacrilate augmented gentamicin. The patients were evaluated by modified Harris Hip Score (HHS) and by SF-12 score. The mean follow up was 25 months (10–45).

Results: The average HHS was 86/4 and its pain component was 38.8. The average physical component of SF-12 was 45.9 (19.5–57.2) and the average metal component was 54.6 (29–66.9). The post-operative HHS and the SF-12 scores were high (good or excellent) in all patients reflecting good clinical outcome. In patients who were asymptomatic prior to surgery, both the HHS and the pain score were significantly higher compared to the symptomatic patients (p< 0.01). One patient with extensive bone loss needed revision surgery due to early postoperative fracture of the acetabulum, and another patient had recurrent dislocations that required revision.

Summary: We conclude that revision of the polyethylene liner and cementation of a new one is a safe and useful technique in patients with stable acetabular shell. This is especially true for asymptomatic patients with osteolysis.

Introduction. Osteolysis is a periprosthetic bone loss associated with both cemented and noncemented arthroplasties. It is believed to be caused by cellular reaction to wear particles, especially from polyethylene, and is considered to be a major source of morbidity following total hip replacement. Roentgenographycally it appears as a diffuse cortical thinning or focal cystic lesion, but major bone loss may precede this finding. In advanced osteolysis, implant stability is impaired, and component revision is mandatory. Thus early detection of osteolysis is crucial to allow minor procedure of curettage and insert revision.

Three dimensional imaging tool for early detection and follow up of the osteolytic cysts is needed. The conventional CT incorporates streak artifacts around metallic implants that make the interpretation of the images extremely unreliable. We report our preliminary experience with new 16-slice CT techniques that improve the diagnosis of osteolysis.

Materials and methods. Twenty one patients with suspected osteolysis underwent CT examination of the involved region with a new 16-slice GE Lightspeed scanner. 16 patients had a hip arthroplasty and 5 patients a knee arthroplasty. Different slice thickness was examined. Standard, soft and boneplus filters were tested for the axial images and reconstructions. MPR with 0.625mm, 1.25 and 2.5mm slice thickness, 3D-MIP and VR reconstruction methods were performed for each patient and the best technique for minimizing streak artifacts and evaluation of periprosthetic bone was determined by two radiologists and an orthopedic surgeon.

Results. The axial images in various slice thickness showed massive streak artifacts but the thinner slices of 0.625mm showed better demonstration of fine bony details around the prosthesis. Standard filter was superior compared to the soft and boneplus filters for bony changes. MPR and MIP reconstructions reduced markedly the impact of the metal artifacts but MPR using 1.25mm slice thickness was superior to MIP for appreciation of the texture of the periprosthetic bone.

Conclusions. In our study, a proper technique of 16-slice computerized tomography allows early detection and follow up of osteolytic lesions, that may significantly help in the decision making process, and may enable avoiding major surgery.

Introduction and Aims: The incidence and technical complexity of revision total hip arthroplasty (THA) has and will continue to increase dramatically. We report the results of revision THA using a non-cemented, dual threaded, cone shaped, (DTCS) modular femoral component.

Method: Between June of 1999 and July of 2003, 41 revision THAs using a DTCS modular femoral component. Fifty-four percent of the patients were male and 46% were female with an average weight of 84kg (std dev: 30kg, range 57–60 kg), an average height of 170cm (sdt dev: 9cm, range: 155–182 cm) and an average body mass index (BMI) of 26 (std dev: 4, range: 18–31). The average patient age was 71 years (std dev: 12 years, range: 39–85 years).

Results: The average patient follow-up was 16 months (range 6–49 months). The average Harris hip score (HHS) at the most recent time to follow-up was 76. Broken into the HHS component parts, the average pain score was 40 of a possible 44, average motion was nine of a possible nine, and average function was 28 of a possible 47. Radiographic evaluation revealed wellfixed and positioned components with evidence of bone densing in areas in intimate contact with the DTCS component. Radiographic evidence of minor stress shielding was observed in the greater trochanter (Gruen Zone 1) and the proximal calcar/neck cut region (Gruen Zone 7). Post-operative complications included recurrent infection in four (10%), subsequently resolved with IV antibiotics; dislocation in three (7%), successfully treated by closed reduction and protective bracing; aseptic loosening in one (2%), with femoral component revision to a larger size; intra-operative periprosthetic fracture in one (2%), treated with ORIF (bone, plate and screws); and a non-union of a pre-revision fracture with subsequent component loosening in one (2%). Regardless of the degree of femoral deficiency, there was no incidence of component disassociation or component fracture.

Conclusion: Revision THA is a demanding undertaking and involves multivariate technical challenges that may include mechanical and material considerations such as prosthetic loosening, prosthetic and periprosthetic fracture. We show that the use of a DTCS modular femoral component affords the surgeon results equal to those reported for revision THA and allows intra-operative versatility independent of bone quality.

Background: A totally new double-threaded cone-shaped modular femoral stem has been designed, using rotational rather than percussive hammer insertion of the prosthesis. The vertical height, the neck length, the neck anteversion angle and the medial offset can all be adjusted after preparation of the femoral canal has been completed.

Methods: The new stem design and the technique of insertion are described. A consecutive series of the first 110 hip joints in 103 patients were followed clinically and radiographically for an average of 28 months.

Results: The Harris hip score average rose from 43.6 points preoperatively to 91 points postoperatively. The pain score average changed from 7.9 points to 42 points, respectively. Thirteen hips (11.8%) had mid-thigh pain, most of them mild. One hip (0.9%) showed clinical and radiographic signs of early loosening and was revised.

Conclusions: The short-term clinical and radiographic outcomes were encouraging. The double-threaded cone-shaped stem locking mechanism was shown to be able to withstand the torsional and vertical forces applied to a hip-replacement prosthesis.

Introduction: The double threaded Cone Modular Hip Replacement System has been used in 114 patients as a primary prosthesis in over three years. No patient has been lost to follow up and all patients have been assessed postoperatively for the Harris Hip Score, Pain Score, Dexa analysis as well as plain X-rays.

Method: 114 patients requiring primary hip replacement were entered into a prospective clinical trial over a three year period. The Harris Hip Score, Pain Score and Dexa analysis (Luna 2000 program) and X-rays were assessed at six weeks, three months, six months, twelve months, two years and three years and results were compared with the preoperative figures. Length of hospital stay, discharge details (home or rehabilitation unit) and physiotherapy assessment of time to independent stair climbing was prospectively assessed.

Results: The Dexa analysis indicates a loss of bone at two years at Gruen’s zones one and seven of 25% and at zones two and six of approximately 20% with no increase or loss of bone in zones three, four and five.

The Harris Hip Scores and Pain Scores show a significant improvement comparing preoperative with postoperative results in this series.

One patient required revision of the femoral neck component for recurrent dislocation and three patients have significant rotational thigh pain due to varus implantation of the stem (the pilot has since been shortened and the diameter reduced by 1mm).

Conclusion: The double threaded cone shaped modular hip prosthesis stem allows immediate full weight bearing postoperatively. No prosthesis has loosened or subsided and the locking mechanism has been shown to gain immediate and long term fixation as a primary prosthesis stem.

Clinical assessment, X-rays and Dexa analysis indicate satisfactory results with good incorporation of the prosthesis by the bone.

Background: A total new double-threaded cone-shaped modular femoral stem has been designed, using rotational rather than percussive hammer insertion of the prosthesis. The vertical height, the neck length, the neck anteversion angle and the medial offset can all be adjusted after preparation of the femoral canal has been completed.

Methods: A consecutive series of the first 110 hip joints in 103 patients were followed clinically and radiographically for an average of 28 months.

Results: The mean Harris hip score rose from 43.6 points preoperatively to 91 points postoperatively. The mean pain score changed from 7.9 points to 42 points, respectively.

13 hips (11.8%) had mid-thigh pain, most of them mild. One hip (0.9%) showed clinical and radiographic signs of early loosening and was revised.

Conclusion: The short-term clinical and radiographic outcomes are encouraging. The double-threaded cone-shaped stem locking mechanism has been shown to be able to withstand the torsional and vertical forces applied to hip replacement prosthesis.

Background: Dual-energy X-ray absorptiometry has been validated as an accurate method for assessing periprosthetic bone loss around the femoral stem after uncemented total hip arthroplasty. A prospective longitudinal study was conducted to evaluate bone mineral density (BMD) changes around a series of double-threaded cone-shaped modular femoral stems.

Materials: 64 hips with implanted double-threaded cone-shaped femoral stem were scanned in the anteroposterior femoral plane using a Lunar DPXL densitometer with special software. The initial MBD scan was performed 2–4 weeks after the surgery and thereafter yearly for up to three years.

Results: Significant changes occurred during the first year after surgery. In the proximal femur the mean BMD decreased to 73%±17% (p< 0.001) in the calcar area and to 91%±13% (p< 0.001) in the greater trochanter region. In the middle part of the stem the mean BMD decreased to 86%±17% (p< 0.001) on the medial side and to 84%±12% (p< 0.001) on the lateral side. No significant changes occurred around the distal part of the stem. During the second and third postoperative years, small progressive changes in BMD were noticed in all Gruen zones, in keeping with age-related bone loss.

Conclusion: Significant decreases in BMD around the femoral stem prosthesis in the proximal parts of the femur were recorded during the first postoperative year. These changes may be explained by the metaphyseal-diaphyseal gripping prosthesis design. No significant distal changes were found.

Introduction: Dual-energy x-ray absorptiometry (DEXA) measurement is a valuable and accurate method of assessing periprosthetic bone loss around femoral stems.

Method: The cohort was 21 patients who underwent total hip arthroplasties with double-threaded, cone-shaped, modular, femoral stems and who already had a prosthetic contralateral hip. The contralateral hip arthroplasties were Autophur fully porous coated, Exeter cemented and Charnley cemented stems. DEXA measurements were performed in the anteroposterior femoral plane using a Lunar DPXL densitometer and analysed using the Lunar Orthopaedic Software Package, Version 1.7, designed for periprosthetic measurements. The initial measurement was performed between two and four weeks after the surgery as a baseline and then repeated after three, six, 12 and 24 months. The DEXA scan results were analysed comparing the bone density of the double-threaded cone-shaped modular femoral stem side with the contralateral side in a longitudinal study.

Results: The contralateral hip bone quality remained fairly constant in keeping with the maturity of the hip arthroplasties. The insertion of the double-threaded cone-shaped modular femoral stem caused the expected initial bone loss in Gruen zones one and seven due to proximal stress-shielding. Only minor bone loss occurred distally, reflecting good fixation and load transfer of the prosthesis.

Background: Dual-energy x-ray absorptiometry has been validated as an accurate method for assessing periprosthetic bone loss around the femoral stem after uncemented total hip arthroplasty. A prospective longitudinal study was conducted to evaluate bone mineral density (BMD) changes around a series of double-threaded cone-shaped modular femoral stems.

Methods: Sixty-two hips with implanted double-threaded cone-shaped femoral stems were scanned in the antero-posterior femoral plane using a Lunar DPXL densitometer with special software. The initial BMD scan was performed between two and four weeks after the surgery and thereafter yearly for up to three years.

Results: Significant changes occurred during the first year after surgery. In the proximal femur the mean BMD decreased to 73%, by17% in the calcar area and to 91%, by13% in the greater trochanter region. In the middle part of the stem the mean BMD decreased to 86%, by 17% on the medial side and to 84%, 12% on the lateral side. No significant changes occurred around the distal part of the stem. During the second and third postoperative years, small progressive changes in BMD were noticed in all Gruen zones, in keeping with age-related bone loss.

Conclusions: Significant decreases in BMD around the prosthetic femoral stem in the proximal parts of the femur were recorded during the first postoperative year. These changes may be explained by the metaphyseal-diaphyseal gripping prosthesis design. No significant distal changes were found.