The clinical outcome of total knee arthroplasty is compromised by a previously implanted medial unicondylar knee arthroplasty

OBJECTIVE

To investigate the clinical outcome of patients that underwent conversion of a medial unicondylar knee arthroplasty (UKA) to a total knee arthroplasty (TKA) and to compare that outcome to patients that underwent primary TKA. It was hypothesized that those groups would significantly differ in terms of knee score outcome and implant survival.

METHODS

A retrospective-comparative study was conducted utilizing data from the Federal state's arthroplasty registry. Included were patients from our department that undergone a conversion of a medial UKA to a TKA (UKA-TKA group). The Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) from preoperative and 1-year postoperative was used. Moreover, the implant survival was analyzed.

RESULTS

In the UKA-TKA group, there were 51 cases (age 67 ± 10, 74% women), and in the TKA group, there were 2247 cases (age 69 ± 9, 66% women). The one-year postoperative WOMAC total score was 33 in the UKA-TKA group und 21 in the TKA group (p < 0.001). Similarly, the WOMAC pain, WOMAC stiffness, and WOMAC function scores were significantly worse in the UKA-TKA. After 5 years, the survival rates were 82% and 95% (p = 0.001). The 10-years prosthesis survival was 74% and 91% in the UKA-TKA and TKA groups, respectively (p < 0.001).

CONCLUSIONS

Based on our findings it is concluded that patients who received a TKA after UKA have inferior results than those that directly receive a TKA. This is true for both patient-reported knee outcome and prosthesis survival. Converting UKA to TKA should not be seen as an easy operation, but should rather be done by surgeons with considerable experience in both primary and revision knee arthroplasty.

Brake response time returns to the pre-surgical level 6 weeks after unicompartmental knee arthroplasty

PURPOSE

The objective of the study was to clarify whether driving abstinence should be recommended when patients are discharged from hospital after unicompartmental knee arthroplasty (UKA). We tested the hypotheses that there are differences in the peri-operative course of brake response time in patients undergoing right-sided (1) or left-sided (2) UKA. Additionally, we tested whether brake response time is significantly influenced by pain (3), driving experience (4) or age (5).

METHODS

In 43 patients undergoing UKA, brake response time was measured with a custom-made driving simulator pre-operatively and 1 and 6 weeks after UKA. Patients' visual analogue scales for knee pain and their self-reported driving experience were also assessed.

RESULTS

In patients with right-sided UKA, brake response time changed from 786 (261) ms pre-operatively to 900 (430) ms 1 week post-operatively (p = 0.029). At 6 weeks post-operatively, brake response time had returned to 712 (139) ms, which was deemed to be an insignificant change from the pre-operative reference benchmark. When surgery was performed on the contralateral left side, no effect was found onto the right side's brake response time. Knee pain and driving experience were significantly correlated with brake response time. No such correlations were found between brake response time and age.

CONCLUSIONS

On the basis of the current findings, it is concluded that brake response time returns to pre-operative levels 6 weeks after UKA surgery. Therefore, it is proposed that driving be abstained from for that period.

[The direct anterior approach to the hip revision]

OBJECTIVE

The objective of this paper is to describe a minimally invasive approach to revision total hip arthroplasty.

INDICATIONS

Indications for revision hip arthroplasty are septic or aseptic loosening of one or both components of a hip arthroplasty. In revisions the direct anterior approach (DAA) allows for a small incision if only the cup has to be revised or in cases of stem revision; the femoral preparation can be performed strictly endofemorally from the proximal direction. The gluteal muscles can be preserved whether the approach is limited to the original interval between the musculus tensor fasciae latae and the rectus, or has to be extended.

CONTRAINDICATIONS

If preservation of the gluteal muscles is desired, the DAA and its extension are the method of choice. For endofemoral revision other than detachment of the musculus tensor fasciae latae, hyperextension and adduction of the operated leg are important. If these cannot be achieved, an alternative operative strategy or a different approach should be considered. As this approach allows for extensions proximally and distally along the femur, it competes with lateral approaches to the hip joint and femur, and does not have additional specific contraindications. The availability of specific curved, angulated, or offset instruments is mandatory.

SURGICAL TECHNIQUE

The starting point of the incision is found two fingerbreadths lateral and two finger breadths distal to the anterior superior iliac spine. The fascia of the musculus tensor fasciae latae is incised sharply at its midpoint. The interval is prepared strictly subfacially and medially to the musculus tensor fasciae latae to expose the hip joint.

POSTOPERATIVE MANAGEMENT

For this approach we don't have any specific recommendations. Postoperative management depends mostly on the extension of the approach and the type of reconstruction performed. If the approach can be limited to the minimally invasive direct anterior portal, reduced muscle damage should result in faster rehabilitation.

RESULTS

The retrospective analysis was performed on the data obtained from 48 revision operations with the minimally invasive direct anterior approach to total hip arthroplasty. The median cut-suture time was 108 min (42-282 min); patients spent a median time of 10 days (4-33 days) in the hospital from the day of the operation. The most common revision operations were cup replacement with an augmentation ring (13 out of 48), stem revision (11 out of 48), cup replacement (9 out of 48), H-TEP complete (3 out of 48), removing of ossifications (2 out of 48), cap revision (2 out of 48) and H-TEP removal with insertion of a spacer (2 out of 48). Complications attributed to the procedure were reported in 9 of the 48 cases: 1 wound-healing disorder, 1 late infection, 1 hematoma, 1 deep vein thrombosis, 1 perforation (by the spacer) and 1 ossification. Two patients were diagnosed with trochanteric pain syndrome. In one case an implant loosening was diagnosed 12 months after the revision.

Cost-effectiveness of universal ultrasound screening compared with clinical examination alone in the diagnosis and treatment of neonatal hip dysplasia in Austria

Between 1978 and 1997 all newborns in the Austrian province of Tyrol were reviewed regarding hip dysplasia and related surgery. This involved a mean of 8257 births per year (7766 to 8858). Two observation periods were determined: 1978 to 1982 (clinical examination alone) and 1993 to 1997 (clinical examination and universal ultrasound screening). A retrospective analysis compared the number and cost of interventions due to hip dysplasia in three patient age groups: A, 0 to < 1.5 years; B, ≥ 1.5 to < 15 years; and C, ≥ 15 to < 35 years.

In group A, there was a decrease in hip reductions from a mean of 25.2 (sd 2.8) to 7.0 (sd 1.4) cases per year. In group B, operative procedures decreased from a mean of 17.8 (sd 3.5) to 2.6 (sd 1.3) per year. There was a 75.9% decrease in the total number of interventions for groups A and B.

An increase of €57 000 in the overall cost per year for the second period (1993 to 1997) was seen, mainly due to the screening programme. However, there was a marked reduction in costs of all surgical and non-surgical treatments for dysplastic hips from €410 000 (1978 to 1982) to €117 000 (1993 to 1997). We believe the small proportional increase in costs of the universal ultrasound screening programme is justifiable as it was associated with a reduction in the number of non-surgical and surgical interventions. We therefore recommend universal hip ultrasound screening for neonates.

Migration of hip revision stems into the knee joint: alternative treatment modalities: technical note

We report two unusual cases of stem penetration of long shaft femoral prosthesis into the knee joint after revision total hip arthroplasty. In both patients, the protruded tip of the stem interfered with the tibial plateau and averted the knee joint from full range of motion. To avoid further extensive surgery, the tips of the femoral stem were excised using a high speed-cutter. Both patients had immediate improvement in range of motion postoperatively, fast and uncomplicated rehabilitation, immediate pain relief, and good radiological results. If this rare complication occurs, we recommend for a primary intervention to cut the tip of the stem because replacement of the prosthesis would be a long lasting and very exhaustive surgery for affected patients.

Correlation between objective gait parameters and subjective score measurements before and after total knee arthroplasty

The absence of uniformity, the use of different terminologies, and the diversity of methods used to translate numerical data into clinical outcomes have been described as potential problems when dealing with clinical knee scores for total knee arthroplasty (TKA). Gait analysis is believed to provide more objective parameters. The aim of the present study was to obtain information about the correlation between the outcome in terms of locomotion and the clinical knee score after TKA. Thirty consecutive patients awaiting TKA were involved in the study. One day prior to surgery and 3 months postoperatively, data pertaining to the Hospital for Special Surgery Score (HSS) and the Knee Society Score (KSS) (subgroups 'pain', 'knee', 'function' and 'total sum') were analyzed for correlations with kinematic and temporospatial parameters of gait analysis. At a significance-level of p</=0.001 moderate correlations (0.4<r<0.6) were found preoperatively, particularly between 'max knee flexion swing' and the function-subscores of HSS and KSS and the 'KSS total'. High correlations (0.6<r<0.8) were ascertained for 'stride length' and 'gait velocity' with 'KSS function'. High correlations were also determined between 'stride length' and 'KSS total' and between 'gait velocity' and 'HSS function'. The only correlation found postoperatively was between 'max pelvic obliquity stance' and 'KSS knee' (r=0.770, p<0.001). We conclude that the 'function' subscores of KSS and HSS are highly suitable to assess the functional capacity of patients scheduled for TKA. However, because no adequate correlations between knee scores and gait parameter were found postoperatively, we cannot recommend the abandonment of gait analysis when monitoring the functional benefit of TKA.

Frontal plane leg alignment and muscular activity during maximum eccentric contractions in individuals with and without patellofemoral pain syndrome

PURPOSE

The role of frontal plane tibiofemoral alignment in subjects with patellofemoral pain syndrome (PFPS) is controversial and rarely discussed in the literature. As well, little research has been done on the effects of the hamstrings muscles on PFPS. The aim of the current study was to determine whether, in individuals with PFPS, frontal plane tibiofemoral alignment or muscular activity of the index knee's crossing muscles is altered during maximum eccentric leg press exercise.

METHODS

This cross-sectional study involved 19 patients with PFPS and 19 control subjects who were matched according to gender, age, and physical activity. During eccentric leg press action, frontal plane tibiofemoral alignment was assessed with a motion analysis system based on skin markers. Simultaneously, surface-electromyography was used to assess the activity levels of the relevant knee crossing muscles. To assess the activity under functional conditions, a leg press with a footplate having variable stability was used for barefoot testing.

RESULTS

The PFPS subjects did not have significantly different frontal plane leg alignment compared to controls. On electromyography (EMG), PFPS patients had significantly lower levels of hamstring activity during eccentric leg exercise. The differences between the two groups (%; absolute differences normalized EMG) ranged from 20% (semitendinosus; stable footplate; p=0.017) to 21% (biceps femoris; unstable footplate; p=0.019) and 32% (semitendinosus; unstable footplate; p=0.002).

CONCLUSIONS

PFPS is not linked to altered frontal plane leg alignment during eccentric leg pressing. However, PFPS is associated with eccentric under-activation of the hamstrings, which may be a compensatory strategy that maintains patellofemoral joint pressure within bearable levels.

Complications and patient satisfaction after periacetabular pelvic osteotomy

Periacetabular osteotomy (PAO) is a well established method to treat hip dysplasia in the adult. There is, however, a lack of information on the subjective outcome of patients with complications after PAO. The purpose of this study was therefore to assess the influence of complications on the patients' post-operative wellbeing and function: 60 PAOs on 50 patients were investigated retrospectively after a mean follow-up of 7.4 years. The patients' self-reported assessment of health and function was evaluated by the Medical Outcomes Short Form-36 (SF-36) and the Western Ontario and McMaster Universities (WOMAC) questionnaires at last follow-up. Forty healthy persons served as a control group. Of the 60 interventions 13 had no complications. Minor complications occurred in 25 (41%) and in 22 (37%) at least one major complication occurred. SF-36 summary measure was 76.4 for PAO patients and 90.3 for the control group. Mean WOMAC score was 25.1. Patients with major complications had a similar subjective outcome as patients with minor or without complications, but persistent dysaesthesia due to lateral femoral cutaneous nerve dysfunction led to a worse subjective function. Lesions of the lateral femoral cutaneous nerve have much greater influence on patients' self-assessed functional outcome after PAO than previously reported and greater attention has to be given to this supposedly minor complication.

Strategies for prevention and management of musculoskeletal conditions. Low back pain (non-specific)

Low back pain (LBP) is defined as pain localised between the 12th rib and the inferior gluteal folds, with or without leg pain. Most cases are non-specific, but in about 10% of cases a specific cause is identified. Red flags are typical signs or symptoms that are frequently associated with specific LBP. Yellow flags are prognostic factors associated with a more unfavourable and often chronic disabling course of the disease. LBP has a lifetime prevalence of 60-85%. At any one time, about 15% of adults have LBP. LBP poses an economic burden to society, mainly in terms of the large number of work days lost (indirect costs) and less so by direct treatment costs. A substantial proportion of individuals with chronic LBP has been found to have chronic widespread pain. LBP is often associated with other pain manifestations such as headache, abdominal pain and pain in different locations of the extremities. Widespread pain is associated with a worse prognosis compared to localised LBP. Treatment targets are reduction of pain and better activity/participation, including prevention of disability as well as maintainance of work capacity. The evidence from selected and appraised guidelines, systematic reviews and major clinical studies was classified into four levels, level Ia being the best level with evidence from meta-analysis of randomised controlled trials. Key recommendations (level Ia): fitness programmes and advice to stay active can reduce pain, improve function and can prevent LBP becoming chronic. Simple analgesics, NSAIDs and muscle relaxants can reduce pain and can improve and maintain function. Maintaining physical activity, avoiding rest and manual therapy can reduce pain and maintain and restore function in acute LBP. Behavioural treatment can prevent LBP becoming chronic. Aerobic fitness and endurance training, behavioural treatment and multi-disciplinary treatment programmes can reduce pain and can improve/maintain function in chronic LBP.

Uncompromised quality of the cement mantle in Exeter femoral components implanted through a minimally-invasive direct anterior approach

A complete cement mantle is important for the longevity of a total hip replacement. In the minimally-invasive direct anterior approach used at the Innsbruck University hospital, the femoral component has to be inserted into the femoral canal by an angulated movement. In a cadaver study, the quality and the extent of the cement mantle surrounding 13 Exeter femoral components implanted straight through a standard anterolateral transgluteal approach were compared with those of 13 similar femoral components implanted in an angulated fashion through a direct anterior approach. A third-generation cementing technique was used. The inner and outer contours of the cement mantles was traced from CT scans and the thickness and cross-sectional area determined.

In no case was the cement mantle incomplete. The total mean thickness of the cement mantle was 3.62 mm (95% confidence interval 3.59 to 3.65). The mean thickness in the group using the minimally-invasive approach was 0.16 mm less than that in the anterolateral group. The distribution of the thickness was similar in the two groups. The mean thickness was less on the anteromedial and anterolateral aspect than on the posterior aspect of the femur.

There is no evidence that the angulated introduction of Exeter femoral components in the direct anterior approach in cadavers compromises the quality, extent or thickness of the cement mantle.

Cementless hemiarthroplasty in femoral neck fractures: evaluation of clinical results and measurement of migration by EBRA-FCA

Aim of the present study was to evaluate migration rates of cementless primary hemiarthroplasty in acute femoral neck fractures. In a longitudinal, prospective study 46 patients were treated by cementless hemiarthroplasty. Clinical follow up was correlated with the EBRA-FCA method. In 30% of all patients stem migration amounted to more than 2 mm; further, these patients were seen to have a high level of activity. A high degree of migration in more than 30% of all patients requires critical scepticism toward further use of the investigated cementless stem as hemiarthroplasty. According to literature, migration of more than 2 mm suggests a high probability of early aseptic loosening. In patients with a low degree of activity good results could be observed; nevertheless, in patients with a high level of activity the combination of the investigated cementless stem with a solid fracture head cannot be recommended.

Reducing the risk of dislocation after total hip arthroplasty: the effect of orientation of the acetabular component

Malposition of the acetabular component is a risk factor for post-operative dislocation after total hip replacement (THR). We have investigated the influence of the orientation of the acetabular component on the probability of dislocation. Radiological anteversion and abduction of the component of 127 hips which dislocated post-operatively were measured by Einzel-Bild-Röentgen-Analysis and compared with those in a control group of 342 patients. In the control group, the mean value of anteversion was 15 degrees and of abduction 44 degrees. Patients with anterior dislocation after primary THR showed significant differences in the mean angle of anteversion (17 degrees), and abduction (48 degrees) as did patients with posterior dislocation (anteversion 11 degrees, abduction 42 degrees). After revision patients with posterior dislocation showed significant differences in anteversion (12 degrees) and abduction (40 degrees). Our results demonstrate the importance of accurate positioning of the acetabular component in order to reduce the frequency of subsequent dislocations. Radiological anteversion of 15 degrees and abduction of 45 degrees are the lowest at-risk values for dislocation.

EBRA-FCA for measurement of migration of the femoral component in surface arthroplasty of the hip

Studies on the migration of an implant may be the only way of monitoring the early performance of metal-on-metal prostheses. The Ein Bild Roentgen Analyse--femoral component analysis (EBRA-FCA) method was adapted to measure migration of the femoral component in a metal-on-metal surface arthroplasty of the hip using standard antero-posterior radiographs. In order to determine the accuracy and precision of this method a prosthesis was implanted into cadaver bones. Eleven series of radiographs were used to perform a zero-migration study. After adjustment of the femoral component to simulate migration of 3 mm the radiographs were repeated. All were measured independently by three different observers. The accuracy of the method was found to be +/- 1.6 mm for the x-direction and +/- 2 mm for the y-direction (95% percentile). The method was validated using 28 hips with a minimum follow-up of 3.5 years after arthroplasty. Seventeen were sound, but 11 had failed because of loosening of the femoral component. The normal (control) group had a different pattern of migration compared with that of the loose group. At 29.2 months, the control group showed a mean migration of 1.62 mm and 1.05 mm compared with 4.39 mm and 4.05 mm in the failed group, for the centre of the head and the tip of the stem, respectively (p = 0.001). In the failed group, the mean time to migration greater than 2 mm was earlier than the onset of clinical symptoms or radiological evidence of failure, 19.1 versus 32.2 months (p = 0.001) and 24.8 months (p = 0.012), respectively. EBRA-FCA is a reliable and valid tool for measuring migration of the femoral component after surface arthroplasty and can be used to predict early failure of the implant. It may be of value in determining the long-term performance of surface arthroplasty.

Radiographic evaluation of the Duraloc cup after 4 years

We implanted 71 metal-backed, porous-coated, hemispheric, press-fit Duraloc-100 cups in 68 consecutive patients. In 61 patients, the femoral stem was a cementless Spotorno and in ten a cemented Lubinus SP II. A 28-mm Biolox ceramic head was used with both stems. After an average follow-up of 4 (3.7-5.9) years, we examined 67 hips. Radiolucencies were described in three zones according to DeLee and Charnley, and migration was measured on serial radiographs using the computer-assisted EBRA method. Total migration of more than 1 mm within the first 2 years occurred in 22/62 cups. Nine cups showed more than 1.5 mm total migration within the first 2 years and more than 2 mm within the whole period. The presence of post-operative radiolucencies correlated significantly with a total migration value of more than 2 mm within the first 2 years (p=0.02). Post-operative radiolucencies in zone 1 correlated with a total migration value of more than 2 mm within the first 2 years (p=0.027) and more than 2.5 mm within the whole period (p=0.051). These correlation values might reflect the quality of operative technique, particularly reaming, and implant selection.

Comparison of conventional versus minimally invasive extraperitoneal approach for anterior lumbar interbody fusion

The purpose of the study was to compare conventional versus minimally invasive extraperitoneal approach for anterior lumbar interbody fusion (ALIF). Fifty-six consecutive patients with spondylolisthesis, lumbar instability, or failed back syndrome were treated with ALIF between 1991 and 2001. The patients were retrospectively evaluated and divided in two groups: Group 1, consisting 33 patients, was treated with ALIF using the conventional retroperitoneal approach, and Group 2, consisting of 23 patients, was operated with the minimally invasive muscle-splitting approach for ALIF. The groups were comparable as regards age, indication of fusion, and diagnosis. All patients in both groups had fusion with autologous iliac crest grafts and posterior instrumentation with posterolateral fusion in the same sitting. Clinical evaluation was done by two questionnaires: the North American Spine Society (NASS) Lumbar Spine Outcome Assessment Instrument and the Nottingham Health Profile (NHP). Fusion rate was evaluated radiologically. Mean clinical follow-up was 5.5 years. There was no statistical difference in the occurrence of complications with both approaches nor with the fusion rates of 92% in group 1 and 84% in group 2 respectively. The minimally invasive extraperitoneal approach for ALIF was associated with significantly less intraoperative blood loss, operation time, and length of the skin incision. In addition, this approach showed significant improvement in postoperative back pain in comparison to the conventional approach for ALIF.

[Videotape preparation of patients before hip replacement surgery improves mobility after three months]

Long-term follow-up investigations of the effect of psychological preparation on postoperative physical outcome measures have very rarely been done. In this study a three-month follow-up of a previous investigation of videotape preparation before hip replacement surgery is reported. 100 patients who previously participated in a randomized controlled study received physical examination and x-ray of the hip joint three months after the operation. The mobility of the replaced hip joint was recorded as well as ossifications of the joint. Prepared patients showed a significantly higher improvement of internal rotation, rotational range of motion, and abduction, compared to the controls. The effect sizes ranged between 21% and 32% and, thus, were of clinical relevance. Prepared patients showed less ossifications (15%) that controls (22%), this difference was not significant. For the first time it could be demonstrated that psychological preparation before surgery can not only improve short-term and psychosocial outcome parameters, but also long-term physical measures. The reason for this effect remains to be investigated.

Migration of metal-on-metal versus ceramic-on-polyethylene hip prostheses

In a prospective randomized study, 32 metal-on-metal prostheses and 29 ceramic-on-polyethylene prostheses of similar design were implanted in 59 patients. Radiolucency, cup migration, wear, and function were examined after a minimum of 2 years followup (followup rate, 87%). The purpose of the current study was to evaluate whether higher frictional torque of metal-on-metal will lead to a higher rate of early metal-on-metal cup loosening. A computer-assisted method was used for wear and migration measurements of the acetabular component. Metal-on-metal prostheses migrated in a craniocaudad direction significantly less than ceramic-on-polyethylene prostheses. The mean total migration for both types of prostheses exceeded 1.5 mm at 2 years. Clinically, no difference between the two prostheses regarding activity, pain, or range of motion was found at 2 years. As migration of metal-on-metal prostheses was not higher in comparison with ceramic-on-polyethylene prostheses, the expected higher frictional torque of metal-on-metal prostheses did not increase migration during short-term followup. The different debris produced by both bearings did not influence the short-term results of this study, but might cause different long-term results.

Heat distribution and heat transport in bone during radiofrequency catheter ablation

BACKGROUND

To assess the feasibility of percutaneous radiofrequency ablation in large bone tumours, the heat distribution in cortical bone and marrow around inserted electrodes was measured.

METHODS

Fresh bovine cadaver tibial bones were locally heated through drill holes for a maximum of half an hour using water-cooled single radiofrequency electrodes (Radionics Instruments Inc) by pulsed energy. Temperatures were measured in the marrow canal as well as in cortical bone by thermocouples at various distances from the inserted probes.

RESULTS

Perpendicular to the probe, hyperthermia of more than 50 degrees C could be created in bone marrow in a sphere of approximately 3 cm, and of approximately 1 cm in cortical bone.

CONCLUSION

As irreversible cellular damage can be expected when increasing the temperature to 50 degrees C for a duration of 6 min, this method may be effective for the minimal invasive ablation of neoplasms within human bone in cigar-shaped regions of approximately 3-cm diameter.

[Surgical treatment of idiopathic scoliosis and juvenile kyphosis]

Indication for operative treatment of idiopathic scoliosis and juvenile kyphosis is mainly cosmetic. There is also a higher incidence of pain in scoliosis patients, and reduced pulmonary function in severe deformity, especially in severe deformities present at the age of 5 years (early onset). Scoliotic curves of less than 30 degrees will not progress in adults, whereas curves of 50-75 degrees will further progress a mean of 25 degrees during 40 years. Progression in adults with juvenile kyphosis is not well documented. Operative treatment aims to stop progression, to control spinal growth, or to perform correction and fusion by spinal instrumentation and bone grafts. These goals can be achieved either by an anterior, a posterior, or a combined approach. Correction principles are compression, distraction, derotation and translation. The forces applied by correction are transferred by fixation devices (pedicle screws, anterior screws, hooks, sublaminar wires) to the spine. The higher correction forces are, the higher is the correction achieved, but also the risk of fracture and torn out implants. Mobilisation reduces rigidity and allows to achieve a better correction with equal forces. The best mobilisation techniques are disc excision, facet joint removal, and techniques to mobilise the thorax.

Excessive heat generation during cutting of cement in the Robodoc hip-revision procedure

The ROBODOC system is a promising new method for removing cement with high-speed milling. Heat is generated during the milling process. This study was designed to measure temperatures in the cutting area, and to assess the risk of heat injury and the effectiveness of irrigation. We measured temperatures at the bone-cement cutting area in three experimental settings, two involving the proximal area comprising a cement mantle, and one the distal cement plug beneath the prosthesis. Without cooling facilities, a mean temperature of 94 degrees C was measured in proximal areas. However, this could effectively be reduced below 70 degrees C with irrigation. In the area of the distal cement plug, we measured a mean temperature of 172 degrees C without irrigation. In this area, the integrated irrigation system with an additional high-flow irrigation system could not guarantee cooling to an acceptable temperature of below 70 degrees C since the irrigation stream was impeded by the cutter in the narrow cavity. We need an integrated irrigation device that guarantees continuous cooling at the cutting interface in front of the cutter.

Multiple previous surgeries, infection, and preoperative radiation: a cause for arterial rupture in closed reduction?

We report a patient who underwent revision hip arthroplasty with preoperative radiation after a septic loosening of the primary hip prosthesis. Subsequently the patient presented with a dislocation of the hip. During the closed reduction with general anesthesia, a rupture of the arteria profunda femoris occurred. The patient was treated by angiographic obliteration of the arteria profunda femoris followed by an open reduction and augmentation of the acetabular component.

Knee pain caused by a fiducial marker in the medial femoral condyle: a clinical and anatomic study of 20 cases

After 2-pin-based ROBODOC hip arthroplasty procedures, 10 of 18 patients reported persistent severe pain at the site of pin implantation in the medial femoral condyle. In a cadaver study, we found that the infrapatellar branch of the saphenous nerve, the saphenous nerve and the anterior cutaneous branches of the femoral nerve had been injured by the pins. At least one of these nerves was injured in 11 of the 20 specimens examined. Our findings indicate that the knee-pain may be partly caused by injuries to these nerves.

Radiologic abnormalities and low back pain in elite skiers

Lumbar radiographs of 120 adolescent elite skiers were evaluated for radiologic abnormalities by two independent observers. All athletes had no symptoms before the study. Radiographs were taken before enrollment of the students in elite level training. To determine the clinical significance of these abnormalities, all athletes were observed prospectively during the subsequent 2-year period for development of low back pain under high performance training. Anterior end plate lesions, Schmorl's nodes, posterior end plate lesions, spondylolysis, scoliosis, and spina bifida occulta were found. The depth of anterior end plate lesions showed a two-peak distribution, with peaks at 11% and 22% and a valley at 18% vertebral body height. The overall low back pain incidence was 12.5%. Students with severe anterior lesions (greater than 18% vertebral body height, n = 25) had significantly more low back pain (incidence, 32%) than did students without severe anterior lesions (incidence, 7.4%). Accordingly, students with severe anterior lesions had a significantly higher risk of having low back pain develop. Moderate end plate lesions and other abnormalities were not related to an increased incidence of low back pain. Adolescent students of elite sports with severe lumbar anterior end plate lesions have an increased risk of having low back pain develop under high performance training.

Evaluation of accuracy and precision of bone markers for the measurement of migration of hip prostheses. A comparison of conventional measurements

Our aim was to determine whether tantalum m arkers improved the accuracy and/or precision of methods for the measurement of migration in total hip replacement based on conventional measurements without mathematical correction of the data, and with Ein Bild Roentgen Analyse - Femoral Component Analysis (EBRA-FCA) which allows a computerised correction. Three observers independently analysed 13 series of roentgen-stereophotogrammetric-analysis (RSA)-compatible radiographs (88). Data were obtained from conventional measurements, EBRA-FCA and the RSA method and all the results were compared with the RSA data. Radiological evaluation was also used to quantify in how many radiographs the intraosseous position of the bone markers had been simulated. The results showed that tantalum markers improve reliability whereas they do not affect accuracy for conventional measurements and for EBRA-FCA. Because of the danger of third-body wear their implantation should be avoided unless they are an integral part of the method.

Evaluation of accuracy and precision of bone markers for the measurement of migration of hip prostheses

Our aim was to determine whether tantalum markers improved the accuracy and/or precision of methods for the measurement of migration in total hip replacement based on conventional measurements without mathematical correction of the data, and with Ein Bild Roentgen Analyse – Femoral Component Analysis (EBRA-FCA) which allows a computerised correction. Three observers independently analysed 13 series of roentgen-stereophotogrammetric-analysis (RSA)-compatible radiographs (88). Data were obtained from conventional measurements, EBRA-FCA and the RSA method and all the results were compared with the RSA data. Radiological evaluation was also used to quantify in how many radiographs the intraosseous position of the bone markers had been simulated. The results showed that tantalum markers improve reliability whereas they do not affect accuracy for conventional measurements and for EBRA-FCA. Because of the danger of third-body wear their implantation should be avoided unless they are an integral part of the method.

Comparison of migration in modular sockets with ceramic and polyethylene inlays

This study compared migration in 73 cementless total hip arthroplasties (THAs) with either alumina ceramic (n = 23) or polyethylene (n = 50) inlays; prosthesis sockets and stems were identical except for the inlays. After 7 years of follow-up, 5 sockets (4 with ceramic and 1 with polyethylene inlays) had been revised an average of 63.3 months (range: 49-81 months) after implantation, and survival analysis showed a significantly higher revision rate for sockets with ceramic inlays (89 +/- 6%) versus polyethylene inlays (98.2 +/- 1.7%) (P = .032). Migration analysis of the first three postoperative years revealed significantly higher vertical migration in sockets with ceramic inlays (P = .047), in patients aged <60 years (P = .02), and in osteoporotic type C bone (A versus C, P = .0071 and B versus C, P = .0004).

Pelvic tilt in neuromuscular disorders

The pelvic tilt is part of a complex deformity in which both the spine and the hip are involved. By viewing the different planes and analyzing the deforming forces, four different types of pelvic tilt in combination with spinal and hip deformities can be identified. In spina bifida patients congenital deformities of the spine may add to the progression of scoliosis. Analyzing our own patients we found that certain types of pelvic tilt can be related to certain neuromuscular diseases. Moreover our results show that the pelvic tilt can be effectively corrected by spinal surgery, whereas no effect of hip surgery could be demonstrated.

Motion in lumbar functional spine units during side bending and axial rotation moments depending on the degree of degeneration

STUDY DESIGN

Human lumbar spine specimens were tested in axial rotation and side bending. Motion was related to the grade of degeneration.

OBJECTIVES

To determine the degree to which degeneration with fissure formation in the disc affects axial rotation of the lumbar functional spine unit.

SUMMARY OF BACKGROUND DATA

There is controversy in the literature regarding the influence of severe degeneration and fissures of the disc on the range of axial rotation.

METHODS

Thirty-six lumbar spine specimens were tested in axial rotation and side bending, by applying pure moments in an unconstrained setting. The motion in 6 df was recorded by dial gauges. The grade of degeneration was established by the grading schemes of Nachemson, Thompson, Adams, and Mimura.

RESULTS

A significant increase of axial rotation and lateral translation under torque was found. This increase mainly took place between Grade 3 according to the schemes of Nachemson, Thompson, and Adams (no fissure formation) and the higher grades of degeneration (defined by fissure formation). Reduced disc height was always associated with fissures.

CONCLUSIONS

A reduced lumbar disc height in radiographs seems to be associated with fissure formation in the disc. In this case, the range axial rotation after torque is increased in comparison with cases with less degeneration.

Foot deformities in adolescents and young adults with spina bifida

Spina bifida is generally accompanied by a high incidence of foot deformities. The goal of management is to achieve a plantigrade foot. Deformities are related to the level of the lesion. With thoracic lesions, the most frequent deformity is an equinus lesion (55%), a club foot with mid-lumbar lesion (87%) and a calcaneal foot with sacral lesions (34%). No deformity was present in 56% of feet in sacral lesion children. Club foot surgery before the age of 2 years entails a high rate of recurrence (78%), necessitating redo surgery. A calcaneo-valgus deformity developed in 45% of ambulating patients with sacral lesions requiring operative stabilization of the foot. Patients with sacral lesions were almost the only ones who remained ambulators. Ambulation was not seen to be related to foot deformities in adolescents and young adults.

Videotape preparation of patients before hip replacement surgery reduces stress

OBJECTIVE

Elective surgery represents a considerable source of stress for the patient. Many attempts have been made to prepare patients before surgery with the aim of reducing stress and improving outcome. This study used a novel approach to fulfill this aim by showing a videotape of a patient undergoing total hip replacement surgery, covering the time period from hospital admission to discharge, that strictly keeps to the patient's perspective.

METHODS

Before elective total hip replacement surgery, 100 patients were randomly assigned to a control group or a preparation group; the latter group was shown the videotape on the evening before surgery. Anxiety and pain were evaluated daily for 5 days, beginning with the preoperative day, by means of the State-Trait Anxiety Inventory and a visual analog scale. Intraoperative heart rate and blood pressure, as well as postoperative intake of analgesics and sedatives, were recorded. Urinary levels of cortisol, epinephrine, and norepinephrine were determined in 12-hour samples collected at night for 5 nights, beginning with the preoperative night.

RESULTS

Compared with the control group, the preparation group showed significantly less anxiety on the morning before surgery and the mornings of the first 2 postoperative days, and significantly fewer of them had an intraoperative systolic blood pressure increase of more than 15%. The pain ratings did not differ significantly between the two groups, but the prepared patients needed less analgesic medication after surgery. Prepared patients had significantly lower cortisol excretion during the preoperative night and the first 2 postoperative nights. Excretion of catecholamines did not differ significantly between groups.

CONCLUSIONS

We conclude that use of the videotape decreased anxiety and stress, measured in terms of urinary cortisol excretion and intraoperative systolic blood pressure increase, in patients undergoing hip replacement surgery and prepared them to cope better with postoperative pain.

Measurement of vertebral rotation: a comparison of two methods based on CT scans

This study compared Ho's and Aaro's method to measure vertebral axial rotation in order to find the more accurate one. Two hundred fifty-nine CT scans were taken from 11 cadaver vertebrae. The scans were performed with vertebrae in neutral position and angulated up to 20 degrees in the sagittal and frontal plane to simulate kyphosis/lordosis and side bending. Axial rotation was measured according to both methods. The mean difference between true and measured values was 3.7 +/- 6.7 (95% confidence limit) (Ho's method) and 2.3 +/- 3.7 (Aaro's method), respectively. Correlation with true axial rotation was r2 = 0.66 (Ho's method) and r2 = 0.77 (Aaro's method). We recommend using Aaro's method as the more accurate measure of axial rotation in scoliotic vertebrae.

Accuracy of EBRA-FCA in the measurement of migration of femoral components of total hip replacement. Einzel-Bild-Röntgen-Analyse-femoral component analysis

Several methods of measuring the migration of the femoral component after total hip replacement have been described, but they use different reference lines, and have differing accuracies, some unproven. Statistical comparison of different studies is rarely possible. We report a study of the EBRA-FCA method (femoral component analysis using Einzel-Bild-Röntgen-Analyse) to determine its accuracy using three independent assessments, including a direct comparison with the results of roentgen stereophotogrammetric analysis (RSA). The accuracy of EBRA-FCA was better than +/- 1.5 mm (95% percentile) with a Cronbach's coefficient alpha for interobserver reliability of 0.84; a very good result. The method had a specificity of 100% and a sensitivity of 78% compared with RSA for the detection of migration of over 1 mm. This is accurate enough to assess the stability of a prosthesis within a relatively limited period. The best reference line for downward migration is between the greater trochanter and the shoulder of the stem, as confirmed by two experimental analyses and a computer-assisted design.

Autogenic versus allogenic bone grafts in anterior lumbar interbody fusion

Between 1987 and 1993, 94 consecutive patients with painful spondylolisthesis underwent combined anterior and posterior fusion. The average age at operation was 40 years (range, 16-65 years). Posterior fusion was performed in all patients using pedicle screw systems, and anterior fusion was accomplished with autogenic or allogenic bone grafts. Patients retrospectively were assigned to two groups. In Group 1, anterior fusion was performed with autogenic bone grafts harvested from the iliac crest (n = 65; 146 segments) and in Group 2 allogenic bone grafts were taken from femoral heads (n = 39; 86 segments). The incidence of pseudarthrosis was evaluated on lateral tomograms 24 months after surgery. The mean clinical followup time was 4 years (range, 3-8 years). Pseudarthrosis was found in seven fused levels (3%) managed with autogenic bone grafts (Group 1) and in seven patients (8%) managed with allogenic bone grafts (Group 2). This incidence of pseudarthrosis was not significantly different between the two groups. Considering the possible complications associated with harvesting iliac crest bone, the use of allogenic bone appears justified.

The prediction of failure of the stem in THR by measurement of early migration using EBRA-FCA. Einzel-Bild-Roentgen-Analyse-femoral component analysis

We report the ten-year results for three designs of stem in 240 total hip replacements, for which subsidence had been measured on plain radiographs at regular intervals. Accurate migration patterns could be determined by the method of Einzel-Bild-Roentgen-Analyse-femoral component analysis (EBRA-FCA) for 158 hips (66%). Of these, 108 stems (68%) remained stable throughout, and five (3%) started to migrate after a median of 54 months. Initial migration of at least 1 mm was seen in 45 stems (29%) during the first two years, but these then became stable. We revised 17 stems for aseptic loosening, and 12 for other reasons. Revision for aseptic loosening could be predicted by EBRA-FCA with a sensitivity of 69%, a specificity of 80%, and an accuracy of 79% by the use of a threshold of subsidence of 1.5 mm during the first two years. Similar observations over a five-year period allowed the long-term outcome to be predicted with an accuracy of 91%. We discuss the importance of four different patterns of subsidence and confirm that the early measurement of migration by a reasonably accurate method can help to predict long-term outcome. Such methods should be used to evaluate new and modified designs of prosthesis.

Migration of the Duraloc cup at two years

We carried out 71 primary total hip arthroplasties using porous-coated, hemispherical press-fit Duraloc ‘100 Series’ cups in 68 consecutive patients; 61 were combined with the cementless Spotorno stem and ten with the cemented Lubinus SP II stem. Under-reaming of 2 mm achieved a press-fit. Of the 71 hips, 69 (97.1%) were followed up after a mean of 2.4 years. Migration analysis was performed by the Ein Bild Röntgen Analyse method, with an accuracy of 1 mm.

The mean total migration after 24 months was 1.13 mm. Using the definition of loosening as a total migration of 1 mm, it follows that 30 out of 63 cups (48%) were loose at 24 months.

Migration of the Duraloc cup at two years

We carried out 71 primary total hip arthroplasties using porous-coated, hemispherical press-fit Duraloc '100 Series' cups in 68 consecutive patients; 61 were combined with the cementless Spotorno stem and ten with the cemented Lubinus SP II stem. Under-reaming of 2 mm achieved a press-fit. Of the 71 hips, 69 (97.1%) were followed up after a mean of 2.4 years. Migration analysis was performed by the Ein Bild Rontgen Analyse method, with an accuracy of 1 mm. The mean total migration after 24 months was 1.13 mm. Using the definition of loosening as a total migration of 1 mm, it follows that 30 out of 63 cups (48%) were loose at 24 months.

Different cup migration in rheumatoid arthritis and arthrosis: a radiographic analysis of 127 uncemented acetabular cups

We compared retrospectively the radiographic migration profiles of 82 acetabular components in 61 patients having rheumatoid arthritis with those of 45 hips having arthrosis who underwent a standardized technique of cementless arthroplasty with the Zweymüller prosthesis (Alloclassic). We used a modification of Dickob's technique of digital migration analysis that corrects for magnification errors and horizontal pelvic tilt. The rheumatoid patients were stratified as having oligoarticular, polyarticular, or mutilating arthritis. The overall rate of acetabular loosening in rheumatoid hips after mean 88 (26-117) months was 4%. Loosening was seen only in cases with mutilating arthritis and acetabular protrusion, where the direction of cup migration was also clearly different from that detected in the other types of rheumatoid arthritis and in arthrosis. The different patterns of cup migration in cementless hip replacement for rheumatoid arthritis, depending on disease severity, is of importance when comparing outcome of total hip arthroplasty in rheumatoid patients.

The impact of stressful life events on exacerbation of chronic low-back pain

The impact of stressful life events on the development and onset of chronicity of low-back pain is not yet fully understood. Sixty-four consecutive patients with chronic low-back pain treated at the orthopedic out-patient unit of the Innsbruck University Hospital were investigated with regard to stressful life events. Patients were classified into two groups: one group consisting of patients whose pain had an organic etiology (n= 16), and another group consisting of those with pain of uncertain origin (idiopathic group, n=48). A method combining a semistructured interview with a self-assessment of the severity of stress caused by life events was employed for assessing the impact of such events on chronic low-back pain. In comparison to the patient group having organic causes of pain, the idiopathic group showed significantly more patients having at least one highly stressful event preceding the last substantial aggravation of pain (p=0.028). The latter group experienced significantly more exhaustion (p=0.016) and significantly more difficulties in active coping (p=0.011) when confronted with stressful life events. Stressful life events that arouse feelings of helplessness may contribute to the development of chronic idiopathic low-back pain. Our results emphasize the importance of investigating the subjective meaning and appraisal of stressful life events, taking into consideration both individual predisposition and psychosocial resources available to the patient. Finally, it is also important that the attending physician be aware of any life event that is particularly stressful for the patient so that psychosocial help be made available at the appropriate time.

Comparison of spinal mobility after Harrington and CD instrumentation

Of 229 patients, 15 pairs of patients with right thoracic idiopathic scoliosis (King III) and 15 pairs with combined thoracic and lumbar scoliosis (King II) were identified. Each pair consisted of one patient with Harrington and the other with Cotrel-Dubousset instrumentation. Pairs were comparable with regard to thoracic curve magnitude, and level of end and stable vertebrae. Minimum follow-up was 4 years postoperatively. Spinal mobility of patients in the coronal and sagittal plane, and axial rotation was measured with inclinometers. The differences between operatively treated groups are not significant. The more caudal instrumentation ends, the more reduced is spinal mobility in the coronal plane. Motion in operated patients is significantly reduced in comparison to a healthy reference group.

[Biomechanics of lumbar instability]

Several authors have tried to define segmental lumbar instability. Their definitions: increased antero-posterior translation, pathologic coupled motion, increased neutral zone, pathologic instantaneous center of rotation describe some mechanic findings occurring in the aging spine. However, there is no evidence that they help to differentiate the pathologic entity of segmental lumbar instability from the normal aging process. Dynamic explanation models are promising but at the moment they cannot be used clinically for diagnosis of instability as well. The most important structure to maintain lumbar stability is the intervertebral disc. In the third and fourth decade, more than 50 percent of specimen show peripheral tears of the anulus. It was shown in animal experiments that these tears develop to radial tears, which are accompanied by nuclear volume loss and decreased height. The facets degenerate one or two decades later. Corresponding with the loss of discal function, they increasingly contribute to spinal stability. In conclusion, the concept of lumbar segmental instability is not very helpful in clinical practise. It is recommended to base the decision of lumbar fusion on a painful degenerated disc, and additional findings promising a good result.

[Lumbar fusion in adults--dorsal or combined ventral/dorsal approach?]

A retrospective study was conducted to compare the results of posterior with combined anterior/posterior lumbar fusion in adults. Seventy-six consecutive posterior cases fused with pedicle screws and 46 combined cases were included and followed for at least 2 years. Subjective assessment was based on the Visual Analogue Scales, Waddel Disability and Impairment Score and the GBB for objective quantification of complaints. Furthermore, a thorough clinical examination was done and X-rays including flexion/ extension radiographs, were taken. Questions were asked about the occupational status as well. Pain decreased significantly more in the combined cases than in the posterior fusion cases. In one case a lesion of the common iliac vein occurred during a retroperitoneal approach. Only about half the patients working preoperatively returned to work again. In conclusion, the benefit of better pain relief after combined fusion must be regarded in relation to a higher complication rate due to a second approach.

[Minimally invasive approach and surgical procedures in the lumbar spine]

The history of minimally invasive lumbar spine surgery began in 1963 with the introduction of chemonucleolysis. Like this technique, the later development of mechanical nucleotomy and lasernucleotomy aimed primarily at reduction of the disc pressure. Miniature optical systems offered the opportunity for more specific decompression by discoscopy or, more recently, by transforaminal epiduroscopy. Initially, nucleotomy was the only feasible minimally invasive procedure. In recent years, however, minimally invasive spinal fusion became possible due to the development of new devices (Cages) and advanced transperitoneal (laparoscopic) and retroperitoneal approaches.