Henrik Palm

Prevalence of malformations of the hip joint and their relationship to sex, groin pain, and risk of osteoarthritis: a population-based survey.

BACKGROUND Although the clinical consequences of femoroacetabular impingement have been well described, little is known about the prevalence of the anatomical malformations associated with this condition in the general population, the natural history of the condition, and the risk estimates for the development of osteoarthritis. METHODS The study material was derived from a cross-sectional population-based radiographic and questionnaire database of 4151 individuals from the Copenhagen Osteoarthritis Substudy cohort between 1991 and 1994. The subjects were primarily white, and all were from the county of Østerbro, Copenhagen, Denmark. The inclusion criteria for this study were met by 1332 men and 2288 women. On the basis of radiographic criteria, the hips were categorized as being without malformations or as having an abnormality consisting of a deep acetabular socket, a pistol grip deformity, or a combination of a deep acetabular socket and a pistol grip deformity. Hip osteoarthritis was defined radiographically as a minimum joint-space width of <or=2 mm. RESULTS The male and female prevalences of hip joint malformations in the 3620 study subjects were 4.3% and 3.6%, respectively, for acetabular dysplasia; 15.2% and 19.4% for a deep acetabular socket; 19.6% and 5.2% for a pistol grip deformity; and 2.9% and 0.9% for a combination of a deep acetabular socket and pistol grip deformity. The male and female prevalences of a normal acetabular roof were 80.5% and 77.0%. We found no significantly increased prevalence of groin pain in subjects whose radiographs showed these hip joint malformations (all p > 0.13). A deep acetabular socket was a significant risk factor for the development of osteoarthritis (risk ratio, 2.4), as was a pistol grip deformity (risk ratio, 2.2). Acetabular dysplasia and the subjects sex were not found to be significant risk factors for the development of hip osteoarthritis (p = 0.053 and p = 0.063, respectively). The prevalence of hip osteoarthritis was 9.5% in men and 11.2% in women. The prevalence of concomitant malformations was 71.0% in men with hip osteoarthritis and 36.6% in women with hip osteoarthritis. CONCLUSIONS In our study population, a deep acetabular socket and a pistol grip deformity were common radiographic findings and were associated with an increased risk of hip osteoarthritis. The high prevalence of osteoarthritis in association with malformations of the hip joint suggests that an increased focus on early identification of malformations should be considered.

A new radiological index for assessing asphericity of the femoral head in cam impingement

Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip. The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (alpha) angle and the triangular index, a new measure of asphericity of the femoral head. In addition, the alpha-angle and the triangular index were assessed on the AP and lateral hip radiographs of 82 men and 82 women randomly selected from patients scheduled for total hip replacement (THR). The influence of varying femoral rotation on the alpha angle and the triangular index was also determined in femoral specimens under experimental conditions. From the 2803 radiographs the mean AP alpha-angle was 55 degrees (30 degrees to 100 degrees ) in men and 45 degrees (34 degrees to 108 degrees ) in women. Approximately 6% of men and 2% of women had cam malformation. The alpha-angle and triangular index were highly inter-related. Of those patients scheduled for THR, 36 men (44%) and 28 women (35%) had cam malformation identifiable on the AP radiographs. The triangular index proved to be more reliable in detecting cam malformation when the hip was held in varying degrees of rotation. The combination of the alpha-angle and the triangular index will allow examination of historical radiographs for epidemiological purposes in following the natural history of the cam deformity.

Integrity of the Lateral Femoral Wall in Intertrochanteric Hip Fractures: An Important Predictor of a Reoperation

BACKGROUND Reoperations after intertrochanteric fractures are often necessitated by fracture displacement following mobilization of the patient. The biomechanical complexity of the fracture, the position of the implant, and the patients characteristics are known to influence postoperative outcome. We investigated the importance of an intact lateral femoral wall as a factor in postoperative fracture displacement after fixation with a sliding compression hip screw. METHODS Two hundred and fourteen consecutive patients with an intertrochanteric fracture were treated with a 135 degrees sliding compression hip screw with a four-hole side-plate between 2002 and 2004. The fractures were classified on preoperative radiographs according to the AO/OTA classification system. The status of the greater and lesser trochanters, the integrity of the lateral femoral wall, and the position of the implant were assessed postoperatively. Reoperations due to technical failure were recorded for six months postoperatively. RESULTS Only 3% (five) of 168 patients with an intact lateral femoral wall postoperatively underwent a reoperation within six months, whereas 22% (ten) of forty-six patients with a fractured lateral femoral wall were operated on again (p < 0.001). Multivariate logistic regression analyses combining demographic and biomechanical parameters showed a compromised lateral femoral wall to be a significant predictor of a reoperation (p = 0.010). Seventy-four percent (thirty-four) of the forty-six fractures of the lateral femoral wall occurred during the operative procedure itself. A fracture of the lateral femoral wall occurred in only 3% (three) of the 103 patients with an AO/OTA type-31-A1.1, A1.2, A1.3, or A2.1 intertrochanteric fracture compared with 31% (thirty-one) of the ninety-nine with an AO/OTA type 31-A2.2 or A2.3 fracture (p < 0.001). CONCLUSIONS A postoperative fracture of the lateral femoral wall was found to be the main predictor for a reoperation after an intertrochanteric fracture. Consequently, we concluded that patients with preoperative or intraoperative fracture of the lateral femoral wall are not treated adequately with a sliding compression hip-screw device, and intertrochanteric fractures should therefore be classified according to the integrity of the lateral femoral wall, especially in randomized trials comparing fracture implants.

The effects of liberal versus restrictive transfusion thresholds on ambulation after hip fracture surgery

BACKGROUND: Perioperative anemia leads to increased morbidity and mortality and potentially inhibits rehabilitation after hip fracture surgery. As such, the optimum transfusion threshold after hip fracture surgery is unknown.

Time to Surgery Is Associated with Thirty-day and Ninety-day Mortality After Proximal Femoral Fracture: A Retrospective Observational Study on Prospectively Collected Data from the Danish Fracture Database Collaborators

BACKGROUND We hypothesized that undergoing surgery as soon as possible reduces early mortality in patients with a proximal femoral fracture. Our aim was to evaluate the association between surgical delay and early mortality in these patients. METHODS We performed a retrospective analysis of prospectively collected data from the Danish Fracture Database and the Civil Registration System on patients who were fifty years of age or older and had undergone surgery for a proximal femoral fracture. Femoral head fracture (classified as OTA/AO 31C per the OTA/AO classification system), high-energy trauma, pathological fractures, multiple fractures, and surgeries performed with implants not commonly used were excluded. End points were adjusted odds ratios for thirty-day and ninety-day mortality. RESULTS For the 3517 surgeries included in this study, the median patient age was 82.0 years (range, fifty-one to 107 years), 2458 patients (70%) were female, and 1720 surgeries (49%) were performed because of a trochanteric fracture. Within twelve hours, 722 of the surgeries (21%) had been performed; within twenty-four hours, 2482 surgeries (71%); within thirty-six hours, 3024 surgeries (86%); within forty-eight hours, 3242 surgeries (92%); and within seventy-two hours, 3353 surgeries (95%). Unsupervised surgeons with an education level below that of an attending surgeon performed the surgery in 1807 (51%) of all cases. The thirty-day mortality was 380 (10.8%) and the ninety-day mortality was 612 (17.4%). The risk of thirty-day mortality increased with a surgical delay of more than twelve hours (odds ratio, 1.45; p = 0.02), more than twenty-four hours (odds ratio, 1.34; p = 0.02), and more than forty-eight hours (odds ratio, 1.56; p = 0.02); the risk of ninety-day mortality increased with a surgical delay of more than twenty-four hours (odds ratio, 1.23; p = 0.04). An education level of the surgeon below that of an attending surgeon increased the risk of thirty-day mortality (odds ratio, 1.28; p = 0.035) and ninety-day mortality (odds ratio, 1.26; p = 0.016). Increasing American Society of Anesthesiologists score and male sex significantly increased both thirty-day and ninety-day mortality. CONCLUSIONS In this study, a surgical delay of more than twelve hours significantly increased the adjusted risk of thirty-day mortality and a surgical delay of more than twenty-four hours significantly increased the adjusted risk of ninety-day mortality. The adjusted risk of both thirty-day and ninety-day mortality increased significantly when the education level of the surgeon was below that of an attending surgeon. The study findings challenge orthopaedic departments to facilitate fast surgical treatment supported by attending orthopaedic surgeons.

A new measurement for posterior tilt predicts reoperation in undisplaced femoral neck fractures: 113 consecutive patients treated by internal fixation and followed for 1 year.

Background and purpose Preoperative posterior tilt in undisplaced (Garden I–II) femoral neck fractures is thought to influence rates of reoperation. However, an exact method for its measurement has not yet been presented. We designed a new measurement for posterior tilt on preoperative lateral radiographs and investigated its association with later reoperation. Patients and methods A consecutive series of 113 patients, ≥ 60 years of age with undisplaced (Garden I–II) femoral neck fractures treated with two parallel implants, was assessed regarding patient characteristics, radiographs, and rate of reoperation within the first year. In a subgroup of 50 randomly selected patients, reliability tests for measurement of posterior tilt were performed. Results Intra-and interclass coefficients for the new measurement were ≥ 0.94. 23% (26/113) of patients were reoperated and increased posterior tilt was an accurate predictor of failure (p = 0.002). 14/25 of posteriorly tilted fractures ≥ 20° were reoperated, as compared to 12/88 of fractures with less tilt (p < 0.001). In multiple logistic regression analysis including sex, age, ASA score, cognitive function, new mobility score, time from admission to operation, surgeons expertise, postoperative reduction, and implant positioning, a preoperative posterior tilt of ≥ 20° was the only significant predictor of reoperation (p < 0.001). Interpretation The new measurement for posterior tilt appears to be reliable and able to predict reoperation in patients with undisplaced (Garden I–II) femoral neck fractures.

A new algorithm for hip fracture surgery. Reoperation rate reduced from 18 % to 12 % in 2,000 consecutive patients followed for 1 year.

Background and purpose Treatment of hip fracture patients is controversial. We implemented a new operative and supervision algorithm (the Hvidovre algorithm) for surgical treatment of all hip fractures, primarily based on own previously published results. Methods 2,000 consecutive patients over 50 years of age who were admitted and operated on because of a hip fracture were prospectively included. 1,000 of these patients were included after implementation of the algorithm. Demographic parameters, hospital treatment, and reoperations within the first postoperative year were assessed from patient records. Results 931 of 1,000 operative procedures were performed according to the algorithm, as compared to only 726 of 1,000 prior to its introduction (p < 0.001). After implementation of the algorithm, junior registrars still performed half of the operations, but unsupervised procedures declined from 192 of 1,000 to 105 of 1,000 (p < 0.001). The rate of reoperations declined from 18% to 12% (p < 0.001 in a multiple Cox regression analysis), with a decline of 24% to 18% for intracapsular fractures and a decline of 13% to 7% for extracapsular fractures. The proportion of bed-days caused by reoperations was reduced from 24% of total hospitalization before the algorithm was introduced to 18% after it was introduced. Interpretation It is possible to implement an algorithm for treatment of all hip fracture patients in a large teaching hospital. In our case, the Hvidovre algorithm both raised the rate of supervision and reduced the rate of reoperations. The reduced reoperation rate saved many hospital bed-days.

Intramedullary nailing appears to be superior in pertrochanteric hip fractures with a detached greater trochanter: 311 consecutive patients followed for 1 year.

Background and purpose In recent years, intramedullary nails (INs) for the treatment of pertrochanteric hip fractures have gained prominence relative to conventional, sliding hip screws (SHSs). There is little empirical background for this development, however. A previous series of ours suggested that the use of SHS was not adequate in situations with fragile or fractured lateral femoral walls, where it often led to lack of healing in a maximally telescoped position. We hypothesized that INs would be the superior implant in these specific circumstances. Methods We retrospectively examined 311 consecutive patients treated in our department between 2002 and 2008, with either an IN (n = 158) or an SHS (n = 153) mounted on a 4-hole side-plate, for an AO/OTA type 31A1–2 pertrochanteric fracture with a detached greater trochanter. The status of the lesser trochanter was assessed preoperatively and the integrity of the lateral femoral wall, fracture reduction, and position of the implants were assessed postoperatively. Reoperations due to technical failure were recorded for one year postoperatively. Results Multivariate logistic regression analysis showed that the groups were similar regarding demographic and biomechanical parameters. The lateral femoral wall was more frequently fractured during SHS implantation (42 patients) than in the IN group (9 patients) (p < 0.001). 6 (4%) of the 158 patients operated with IN had to be reoperated, as compared to 22 (14%) in the SHS group of 153 patients (p = 0.001). Interpretation IN had a lower reoperation rate than SHS in these pertrochanteric hip fractures with a detached greater trochanter. IN left more lateral femoral walls intact.

Circumferential wires as a supplement to intramedullary nailing in unstable trochanteric hip fractures: 4 reoperations in 60 patients followed for 1 year.

Background and purpose Fixation of unstable trochanteric fractures is challenging. Application of a circumferential wire may facilitate bone contact and avoid postoperative fracture displacement. However, the use of circumferential wires remains controversial due to possible disturbance of the blood supply to the underlying bone. We evaluated the results of applied circumferential wires, concentrating mainly on complications and reoperations. Patients and methods 60 patients with unstable trochanteric fractures and use of circumferential wires (1 or more) and an intramedullary nail were included from 2 centers. We retrospectively assessed complications and reoperation rates within the first postoperative year. Results In 37 of the 60 patients, 2 or more circumferential wires were used. Anatomic reduction was achieved in 24 of the patients and a total cortical displacement of ≤ 10 mm was achieved in 26 other patients. 6 of the 43 patients with radiographic audit after 12 weeks sustained a subsequent fracture displacement of more than 5 mm. 4 patients underwent reoperation: 1 due to deep infection, 1 due to technical failure during osteosynthesis, 1 had a screw cut out, and 1 sustained a new fracture following a new fall. Interpretation Application of circumferential wires as a supplement to intramedullary nails in unstable trochanteric fractures is an option as it provides good primary reduction which, in most patients, is maintained over time—with no apparent increase in reoperation rate. Based on our results and on other reports, the use of circumferential wires does not appear to be harmful as sometimes claimed.

Precision of radiostereometric analysis (RSA) of acetabular cup stability and polyethylene wear improved by adding tantalum beads to the liner

Background and purpose — In traditional radiostereometric analysis (RSA), 1 segment defines both the acetabular shell and the polyethylene liner. However, inserting beads into the polyethylene liner permits employment of the shell and liner as 2 separate segments, enabling distinct analysis of the precision of 3 measurement methods in determining femoral head penetration and shell migration. Patients and methods — The UmRSA program was used to analyze the double examinations of 51 hips to determine if there was a difference in using the shell-only segment, the liner-only segment, or the shell + liner segment to measure wear and acetabular cup stability. The standard deviation multiplied by the critical value (from a t distribution) established the precision of each method. Results — Due to the imprecision of the automated edge detection, the shell-only method was least desirable. The shell + liner and liner-only methods had a precision of 0.115 mm and 0.086 mm, respectively, when measuring head penetration. For shell migration, the shell + liner had a precision of 0.108 mm, which was better than the precision of the shell-only method. In both the penetration and migration analyses, the shell + liner condition number was statistically significantly lower and the bead count was significantly higher than for the other methods. Interpretation — Insertion of beads in the polyethylene improves the precision of femoral head penetration and shell migration measurements. A greater dispersion and number of beads when combining the liner with the shell generated more reliable results in both analyses, by engaging a larger portion of the radiograph.