An examination chair to measure internal rotation of the hip in routine settings: a validation study

OBJECTIVE: To determine the performance of a newly developed examination chair as compared with the clinical standard of assessing internal rotation (IR) of the flexed hip with a goniometer. METHODS: The examination chair allowed measurement of IR in a sitting position simultaneously in both hips, with hips and knees flexed 90 degrees, lower legs hanging unsupported and a standardized load of 5 kg applied to both ankles using a bilateral pulley system. Clinical assessment of IR was performed in supine position with hips and knees flexed 90 degrees using a goniometer. Within the framework of a population-based inception cohort study, we calculated inter-observer agreement in two samples of 84 and 64 consecutive, unselected young asymptomatic males using intra-class correlation coefficients (ICC) and determined the correlation between IR assessed with examination chair and clinical assessment. RESULTS: Inter-observer agreement was excellent for the examination chair (ICC right hip, 0.92, 95% confidence interval [CI] 0.89-0.95; ICC left hip, 0.90, 95% CI 0.86-0.94), and considerably higher than that seen with clinical assessment (ICC right hip, 0.65, 95% CI 0.49-0.77; ICC left hip, 0.69, 95% CI 0.54-0.80, P for difference in ICC between examination chair and clinical assessment

Bilateral total knee arthroplasty in a patient with hemophilia A, high inhibitor titre and aneurysma spurium of the popliteal artery. A case report

The authors report on bilateral simultaneous knee arthroplasty in a 40-year-old male patient with haemophilia A, high inhibitor titre and an aneurysma spurium of the right popliteal artery. Both knees showed a fixed flexion deformity of 20 degrees. To build up haemostasis, treatment with activated prothrombin complex concentrate (APCC) and recombinant activated factor seven (rFVIIa) was initiated preoperatively. A tourniquet was used on both sides during the operation and factor VIII (FVIII) was administered to further correct coagulopathy. On the eleventh postoperative day the patient complained of increasing pain and pressure in the right knee. An ultrasound suggested aneurysm, which was confirmed by substraction angiography. Under the protection of rFVIIa the aneurysm could be coiled and further rehabilitation was uneventful. At one year post-op the patient presented a range of motion of 90/5/0 degrees for both knees and had returned to full time office work. This case indicates that haemophiliacs with high antibody titre and destruction of both knees can be operated on in one session in order to diminish the operative risk of two consecutive surgical procedures, thus allowing an effective rehabilitation programme. Because of the significant frequency of popliteal aneurysms, preoperative angiography is recommended.

Laser-assisted lipolysis for knee remodelling: A prospective study in 30 patients

Unsightly fat knees are a frustrating aesthetic deformity exacerbated by genetic predisposition and resistance to diet. This article reports our experience with laser-assisted lipolysis (LAL) in knee remodelling.

Is restricted femoral navigation sufficient for accuracy of total knee arthroplasty?

A total knee arthroplasty performed with navigation results in more accurate component positioning with fewer outliers. It is not known whether image-based or image-free-systems are preferable and if navigation for only one component leads to equal accuracy in leg alignment than navigation of both components. We evaluated the results of total knee arthroplasties performed with femoral navigation. We studied 90 knees in 88 patients who had conventional total knee arthroplasties, image-based total knee arthroplasties, or total knee arthroplasties with image-free navigation. We compared patients' perioperative times, component alignment accuracy, and short-term outcomes. The total surgical time was longer in the image-based total knee arthroplasty group (109 +/- 7 minutes) compared with the image-free (101 +/- 17 minutes) and conventional total knee arthroplasty groups (87 +/- 20 minutes). The mechanical axis of the leg was within 3 degrees of neutral alignment, although the conventional total knee arthroplasty group showed more (10.6 degrees ) variance than the navigated groups (5.8 degrees and 6.4 degrees , respectively). We found a positive correlation between femoral component malalignment and the total mechanical axis in the conventional group. Our results suggest image-based navigation is not necessary, and image-free femoral navigation may be sufficient for accurate component alignment.

Effect of multislice acquisition on T1 and T2 measurements of articular cartilage at 3T

PURPOSE: The aim of this study was to investigate the effect of magnetization transfer on multislice T(1) and T(2) measurements of articular cartilage. MATERIALS AND METHODS: A set of phantoms with different concentrations of collagen and contrast agent (Gd-DTPA(2-)) were used for the in vitro study. A total of 20 healthy knees were used for the in vivo study. T(1) and T(2) measurements were performed using fast-spin-echo inversion-recovery (FSE-IR) sequence and multi-spin-echo (MSE) sequence, respectively, in both in vitro and in vivo studies. We investigated the difference in T(1) and T(2) values between that measured by single-slice acquisition and that measured by multislice acquisition. RESULTS: Regarding T(1) measurement, a large drop of T(1) in all slices and also a large interslice variation in T(1) were observed when multislice acquisition was used. Regarding T(2) measurement, a substantial drop of T(2) in all slices was observed; however, there was no apparent interslice variation when multislice acquisition was used. CONCLUSION: This study demonstrated that the adaptation of multislice acquisition technique for T(1) measurement using FSE-IR methodology is difficult and its use for clinical evaluation is problematic. In contrast, multislice acquisition for T(2) measurement using MSE was clinically applicable if inaccuracies caused by multislice acquisition were taken into account. J. Magn. Reson. Imaging 2007;26:109-117. (c) 2007 Wiley-Liss, Inc.

Efficacy and safety of intraarticular hylan or hyaluronic acids for osteoarthritis of the knee: a randomized controlled trial

OBJECTIVE: To compare the efficacy and safety of intraarticular hylan and 2 hyaluronic acids (HAs) in osteoarthritis (OA) of the knee. METHODS: This was a multicenter, patient-blind, randomized controlled trial in 660 patients with symptomatic knee OA. Patients were randomly assigned to receive 1 cycle of 3 intraarticular injections per knee of 1 of 3 preparations: a high molecular weight cross-linked hylan, a non-cross-linked medium molecular weight HA of avian origin, or a non-cross-linked low molecular weight HA of bacterial origin. The primary outcome measure was the change in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score at 6 months. Secondary outcome measures included local adverse events (effusions or flares) in injected knees. During months 7-12, patients were offered a second cycle of viscosupplementation. RESULTS: Pain relief was similar in all 3 groups. The difference in changes between baseline and 6 months between hylan and the combined HAs was 0.1 on the WOMAC pain score (95% confidence interval [95% CI] -0.2, 0.3). No relevant differences were observed in any of the secondary efficacy outcomes, and stratified analyses provided no evidence for differences in effects across different patient groups. There was a trend toward more local adverse events in the hylan group than in the HA groups during the first cycle (difference 2.2% [95% CI -2.4, 6.7]), and this trend became more pronounced during the second cycle (difference 6.4% [95% CI 0.6, 12.2]). CONCLUSION: We found no evidence for a difference in efficacy between hylan and HAs. In view of its higher costs and potential for more local adverse events, we see no rationale for the continued use of hylan in patients with knee OA.

Prevalence of bone attrition on knee radiographs and MRI in a community-based cohort

OBJECTIVES: Bone attrition probably constitutes remodeling of the bone, resulting in flattening or depression of the articular surfaces. Defining bone attrition is challenging because it is an accentuation of the normal curvature of the tibial plateaus. We aimed to define bone attrition on magnetic resonance imaging (MRI) of the knee using information from both radiographs and MRIs, and to assess whether bone attrition is common prior to end stage disease osteoarthritis (OA) in the tibio-femoral joint. METHODS: All knees of participants in the community-based sample of the Framingham OA Study were evaluated for bone attrition in radiographs and MRIs. Radiographs were scored based on templates designed to outline the normal contours of the tibio-femoral joint. MRIs were analyzed using the semi-quantitative Whole-Organ Magnetic Resonance Imaging Scoring (WORMS) method. The prevalence of bone attrition was calculated using two different thresholds for MRI scores. RESULTS: Inter-observer agreement for identification of bone attrition was substantial for the radiographs (kappa=0.71, 95% CI 0.67-0.81) and moderate for MRI (kappa=0.56, 95% CI 0.40-0.72). Of 964 knees, 5.7% of the radiographs showed bone attrition. Of these, 91% of MRIs were also read as showing bone attrition. We selected a conservative threshold for bone attrition on MRI scoring (> or = 2 on a 0-3 scale) based on agreement with attrition on the radiograph or when bone attrition on MRI co-occurred with cartilage loss on OA. Using this threshold for bone attrition on MRI, bone attrition was common in knees with OA. For example, in knees with mild OA but no joint space narrowing, 13 of 88 MRIs (14.8%) showed bone attrition. CONCLUSIONS: Using MRI we found that many knees with mild OA without joint narrowing on radiographs had bone attrition, even using conservative definitions. The validity of our definition of bone attrition should be evaluated in further studies. Bone attrition may occur in milder OA and at earlier stages of disease than previously thought.

Ability of dGEMRIC and T2 mapping to evaluate cartilage repair after microfracture: a goat study

OBJECTIVE: To investigate the ability of delayed gadolinium-enhanced magnetic resonance (MR) imaging of cartilage (dGEMRIC) and T2 mapping to evaluate the quality of repair tissue after microfracture. DESIGN: Twelve knees from 12 goats were studied. An osteochondral defect (diameter, 6mm; depth, 3mm) with microfracture was created in the weight-bearing aspect of both the medial and lateral femoral condyles. Goats were euthanized at 24 weeks (n=6) and 48 weeks (n=6) postsurgery. Pre-contrast R1 (R1pre) and post-contrast R1 (R1post) measurements for dGEMRIC and a pre-contrast T2 measurement for T2 mapping were performed with a 3T MR imaging system. MR imaging findings were compared with histological and biochemical assessments. RESULTS: In native cartilage, significant correlations were observed between the R1post and the glycosaminoglycan (GAG) concentration, as well as DeltaR1 (difference between the R1pre and R1post) and the GAG concentration (P<0.05). In repair tissue, a significant correlation was observed between DeltaR1 and the GAG concentration (P<0.05), but not between the R1post and the GAG concentration. In both repair tissue and native cartilage, no correlation was observed between T2 and the water concentration or between T2 and the hydroxyproline (HP) concentration. A zonal variation of T2 and a clear dependence of T2 on the angles relative to B0 were observed in native cartilage, but not in repair tissue. CONCLUSION: dGEMRIC with DeltaR1 measurement might be useful for the evaluation of the GAG concentration in repair tissue after microfracture. T2 mapping might be useful for the differentiation of repair tissue after microfracture from native cartilage; however, its potential to assess the specific biochemical markers in native cartilage as well as repair tissue may be limited.

Mini-arthrotomy for lateral discoid menisci in children

BACKGROUND: Long-term results after partial, extended, or complete resection of lateral discoid meniscus in children revealed knee arthritis. The purpose of this study was to evaluate whether the operative approach, arthrotomy or arthroscopy, has an impact on the outcome and the development of arthritis. METHODS: A retrospective comparison of 2 well matching groups totaling 40 children with symptomatic lateral discoid meniscus (48 knees, mean age 8.9 years, 13 male and 27 female patients). Meniscus resection was performed via mini-arthrotomy in group 1 (n=17 patients, 20 knees) and arthroscopically in group 2 (n=23 patients, 28 knees). RESULTS: In the follow-up (mean 57 months in group 1, 62 months in group 2), functional results indicated a trend to better results in the International Knee Documentation Committee score (P=0.12) and in the Lysholm score for group 1 (P=0.13) but not in the Ikeuchi score (P=0.48). The comparison of the radiographic arthritis grading in the follow-up showed no significant arthritis in either group (P=0.22). The overall complication rate was similar in both groups (2/20, 10% in group 1; 3/28, 12% in group 2). CONCLUSIONS: Most likely because of the appropriate visualization of the children's joint and the easier instrumentation, the mini-arthrotomy led to slightly superior results compared with those after arthroscopic resection regarding functional outcome and 5 years after surgery. We can recommend the mini-arthrotomy for the resection of lateral discoid meniscus particularly in young children with narrow joint spaces and for surgeons that are not familiar with arthroscopies of small joints. LEVEL OF EVIDENCE: III (therapeutic study, case series with control group).

Mid-term results of transphyseal anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND Optimal therapy for anterior cruciate ligament (ACL) rupture in the paediatric population still provokes controversy. Although conservative and operative treatments are both applied, operative therapy is slightly favored. Among available surgical techniques are physeal-sparing reconstruction and transphyseal graft fixation. The aim of this study was to present our mid-term results after transphyseal ACL reconstruction. METHODS Fifteen young patients (mean age=12.8±2.6, range=6.2-15.8years, Tanner stage=2-4) with open physis and traumatic anterior cruciate rupture who had undergone transphyseal ACL reconstruction with unilateral quadriceps tendon graft were prospectively analyzed. All children were submitted to radiological evaluation to determine the presence of clearly open growth plates in both the distal femur and proximal tibia. Postoperatively, all patients were treated according to a standardized rehabilitation protocol and evaluated by radiographic analysis and the Lysholm-Gillquist and IKDC 2000 scores. Their health-related quality of life was measured using the SF-12 PCS (physical component summary) and MCS (mental component summary) questionnaires. RESULTS Mean postoperative follow-up was 4.1years. Mean Lysholm-Gillquist score was 94.0. Thirteen of the 15 knees were considered nearly normal on the IKDC 2000 score. The mean SF-12 questionnaire score was 54.0±4.8 for SF-12 PCS and 59.1±3.7 for SF-12 MCS. No reruptures were observed. Radiological analysis detected one knee with valgus deformity. All patients had a normal gait pattern without restrictions. CONCLUSION Transphyseal reconstruction of the anterior cruciate ligament shows satisfactory mid-term results in the immature patient.

Vibrations, Posture, and the Stabilization of Gaze: An Experimental Study on Impedance Control

Vibrations, Posture, and the Stabilization of Gaze: An Experimental Study on Impedance Control R. KREDEL, A. GRIMM & E.-J. HOSSNER University of Bern, Switzerland Introduction Franklin and Wolpert (2011) identify impedance control, i.e., the competence to resist changes in position, velocity or acceleration caused by environmental disturbances, as one of five computational mechanisms which allow for skilled and fluent sen-sorimotor behavior. Accordingly, impedance control is of particular interest in situa-tions in which the motor task exhibits unpredictable components as it is the case in downhill biking or downhill skiing. In an experimental study, the question is asked whether impedance control, beyond its benefits for motor control, also helps to stabi-lize gaze what, in turn, may be essential for maintaining other control mechanisms (e.g., the internal modeling of future states) in an optimal range. Method In a 3x2x4 within-subject ANOVA design, 72 participants conducted three tests on visual acuity and contrast (Landolt / Grating and Vernier) in two different postures (standing vs. squat) on a platform vibrating at four different frequencies (ZEPTOR; 0 Hz, 4 Hz, 8 Hz, 12 Hz; no random noise; constant amplitude) in a counterbalanced or-der with 1-minute breaks in-between. In addition, perceived exertion (Borg) was rated by participants after each condition. Results For Landolt and Grating, significant main effects for posture and frequency are re-vealed, representing lower acuity/contrast thresholds for standing and for higher fre-quencies in general, as well as a significant interaction (p < .05), standing for in-creasing posture differences with increasing frequencies. Overall, performance could be maintained at the 0 Hz/standing level up to a frequency of 8 Hz, if bending of the knees was allowed. The fact that this result is not only due to exertion is proved by the Borg ratings showing significant main effects only, i.e., higher exertion scores for standing and for higher frequencies, but no significant interaction (p > .40). The same pattern, although not significant, is revealed for the Vernier test. Discussion Apparently, postures improving impedance control not only turn out to help to resist disturbances but also assist in stabilizing gaze in spite of these perturbations. Con-sequently, studying the interaction of these control mechanisms in complex unpre-dictable environments seems to be a fruitful field of research for the future. References Franklin, D. W., & Wolpert, D. M. (2011). Computational mechanisms of sensorimotor control. Neuron, 72, 425-442.

A novel technique, dynamic intraligamentary stabilization creates optimal conditions for primary ACL healing: A preliminary biomechanical study

BACKGROUND Anterior cruciate ligament (ACL) rupture is a common lesion. Current treatment emphasizes arthroscopic ACL reconstruction via a graft, although this approach is associated with potential drawbacks. A new method of dynamic intraligamentary stabilization (DIS) was subjected to biomechanical analysis to determine whether it provides the necessary knee stability for optimal ACL healing. METHODS Six human knees from cadavers were harvested. The patellar tendon, joint capsule and all muscular attachments to the tibia and femur were removed, leaving the collateral and the cruciate ligaments intact. The knees were stabilized and the ACL kinematics analyzed. Anterior-posterior (AP) stability measurements evaluated the knees in the following conditions: (i) intact ACL, (ii) ACL rupture, (iii) ACL rupture with primary stabilization, (iv) primary stabilization after 50 motion cycles, (v) ACL rupture with DIS, and (vi) DIS after 50 motion cycles. RESULTS After primary suture stabilization, average AP laxity was 3.2mm, which increased to an average of 11.26mm after 50 movement cycles. With primary ACL stabilization using DIS, however, average laxity values were consistently lower than those of the intact ligament, increasing from an initial AP laxity of 3.00mm to just 3.2mm after 50 movement cycles. CONCLUSIONS Dynamic intraligamentary stabilization established and maintained close contact between the two ends of the ruptured ACL, thus ensuring optimal conditions for potential healing after primary reconstruction. The present ex vivo findings show that the DIS technique is able to restore AP stability of the knee.

Association of radiographic osteoarthritis, pain on passive movement and knee range of motion: A cross-sectional study

BACKGROUND Knee pain is associated with radiographic knee osteoarthritis, but the relationships between physical examination, pain and radiographic features are unclear. OBJECTIVE To examine whether deficits in knee extension or flexion were associated with radiographic severity and pain during clinical examination in persons with knee pain or radiographic features of osteoarthritis. DESIGN Cross-sectional data of the Somerset and Avon Survey of Health (SASH) cohort study. METHODS Participants with knee pain or radiographic features of osteoarthritis were included. We assessed the range of passive knee flexion and extension, pain on movement and Kellgren and Lawrence (K/L) grades. Odds ratios were calculated for the association between range of motion and pain as well as radiographic severity. RESULTS/FINDINGS Of 1117 participants with a clinical assessment, 805 participants and 1530 knees had complete data and were used for this analysis. Pain and radiographic changes were associated with limited range of motion. In knees with pain on passive movement, extension and flexion were reduced per one grade of K/L by -1.4° (95% CI -2.2 to -0.5) and -1.6° (95% CI -2.8 to -0.4), while in knees without pain the reduction was -0.3° (95% CI -0.6 to -0.1) (extension) and -1.1° (-1.8 to -0.3) (flexion). The interaction of pain with K/L was significant (p = 0.021) for extension but not for flexion (p = 0.333). CONCLUSIONS Pain during passive movement, which may be an indicator of reversible soft-tissue changes, e.g., reversible through physical therapy, is independently associated with reduced flexion and extension of the knee.

ACL reconstruction with physiological graft tension by intraoperative adjustment of the anteroposterior translation to the uninjured contralateral knee.

PURPOSE Fixation of anterior cruciate ligament (ACL) substitutes with non-physiological anteroposterior translation (APT) worsens outcome. The aim was to present a technique for physiological APT adjustment of the transplant in ACL reconstruction and its outcome at midterm. METHODS In a consecutive series of 28 patients (age 32 ± 11 years, 24 male), chronic ACL deficiency was treated by bone-patella-tendon-bone reconstruction. Transplant APT was adjusted to that of the contralateral uninjured ACL, measured 3, 6, and 12 months postoperatively using the Rolimeter. At a median follow-up of 5.3 years (3-8 years), 82% of the patients were re-evaluated with APT measurement and using IKDC-, Tegner-, Lysholm-Scores, conventional radiographs and MRI. RESULTS No differences in APT (mean ± SD) between uninjured and reconstructed knees were observed after adjustment (6 ± 1 versus 6 ± 1 mm, n.s.). Three months postoperatively, a statistically significant increase in APT (7 ± 1 mm) and a further increase at midterm (9 ± 2 mm) were observed. Patients scored "normal" or "nearly normal", respectively, in 79% (IKDC) and 4 (3-9) points (Tegner; median, range) or 89 ± 9 points (Lysholm; mean ± SD). Radiological evaluation showed no, minimal or moderate joint degeneration in 5, 20 and 75% of patients, respectively. MRI confirmed intact ACL transplants in all patients. CONCLUSION ACL reconstruction using the presented technique was considered successful, as patients did not suffer from subjective instability, radiographic analysis did not provide evidence for graft rupture at midterm. However, APT increase and occurrence of degenerative changes in reconstructed knees at the midterm might not be prevented even by restoration of a physiological APT in ACL reconstruction. The Rolimeter can be used for quick and easy intraoperative indirect control of the applied tension to the ACL transplant by measuring the APT to obtain physiological tensioning resulting in a satisfying outcome at midterm. LEVEL OF EVIDENCE IV.