Per Wretenberg

The foot: still the most important reason for walking incapacity in rheumatoid arthritis: Distribution of symptomatic joints in 1,000 RA patients

Background and purpose Our knowledge of frequency of foot involvement in rheumatoid arthritis (RA) is still often based on a study from Finland in 1956. Great changes in the treatment of RA may have led to a different situation. We investigated the distribution of joint involvement in RA patients today, with special attention given to the feet and subjective walking ability. Methods 1,000 RA patients answered a questionnaire concerning joints affected, joint surgery, foot problems, and subjectively experienced reasons for walking incapacity. Results In 45% of the patients, the forefoot was involved at the start of the disease. In 17%, the hindfoot/ankle was involved at the start. Only hand symptoms were commoner. 80% of patients reported current foot problems, 86% in the forefoot and 52% in the hindfoot/ankle. Difficulty in walking due to the feet was reported by 71%. For 41% of patients, the foot was the most important part of the lower extremity causing reduced walking capacity, and for 32% it was the only part. Interpretation After the hand, the foot was the most frequently symptomatic joint complex at the start of the disease, but also during active medical treatment. The foot caused walking disability in three-quarters of the cases and—4 times as often as the knee or the hip—it was the only joint to subjectively impair gait.

Biomechanics of the knee: methodological considerations in the in vivo kinematic analysis of the tibiofemoral and patellofemoral joint

The purpose of this review article is twofold: to report on the use of intracortical pins to measure three-dimensional tibiofemoral and patellofemoral joint kinematics and highlight methodological concerns associated with this procedure. Tibiofemoral and patellofemoral kinematics has been extensively investigated using reflective markers attached to the surrounding soft tissue of the calf and thigh. However, surface markers may not adequately represent true anatomical locations and skin movement artefacts present the most critical source of measurement error. Consequently, knowledge about skeletal tibiofemoral kinematics is limited, in particular abduction-adduction and internal-external rotations. Considerable questions remain regarding what constitutes normal motion of the knee. A way to avoid the problem of surface markers is use invasive markers to directly measure skeletal motion. To date, many co-ordinate systems have been used to describe three-dimensional skeletal kinematics of the lower limb in vivo. They include helical axes, finite helical axes, instantaneous helical axes, and the joint co-ordinate system based on local anatomic landmarks. Although each method accurately describes the relative motion in 6 d. of f., the differences in how the motion is partitioned may account for the differences across investigations. Additionally, the problem of defining the anatomical co-ordinate system makes comparisons across subjects and studies difficult since subtle differences may be caused by small deviations in the anatomical reference alignment. Cross talk is also a primarily a concern. For joints that articulate principally about one axis, the primary flexion/extension that is registered will be cross-talked into ab/adduction and internal/external rotations.

Orthopaedic surgery of the lower limbs in 49,802 rheumatoid arthritis patients : results from the Swedish National Inpatient Registry during 1987 to 2001

Objectives: To analyse changes in the rates of hospital admission and use of orthopaedic surgery to the lower limbs in Swedish patients with rheumatoid arthritis between 1987 and 2001. Methods: Data for all rheumatoid patients admitted to hospital between 1987 and 2001 were abstracted from the Swedish National Hospital Discharge Register (SNHDR). The data in the register are collected prospectively, recording all inpatient admissions throughout Sweden. The SNHDR uses the codes for diagnoses at discharge and surgical procedures according to the Swedish version of the International Classification of Diseases (ICD). Results: In all, 49 802 individual patients with rheumatoid arthritis were identified, accounting for 159 888 inpatient visits. Hospital admissions for rheumatoid arthritis decreased by 42% (p<0.001) during the period 1987 to 2001. Twelve per cent of all admissions were for a rheumatoid arthritis related surgical procedure to the lower limbs; those admissions decreased markedly (by 16%) between 1987 and 1996, and by 12% between 1997 and 2001, as did the overall number of rheumatoid arthritis related surgical procedures to the lower limbs during both time periods. Between 1997 and 2001, 47% of all rheumatoid arthritis related surgical procedures were total joint arthroplasties. There was an overall trend towards reduced length of hospital stay after orthopaedic surgery to the lower limbs during the study period. Conclusions: Rates of hospital admission and rheumatoid arthritis related surgical procedures to the lower limbs in Swedish patients with rheumatoid arthritis decreased between 1987 and 2001. This may reflect trends in disease severity, management, and health outcomes of this disease in Sweden.

Pain control after total knee arthroplasty: a randomized trial comparing local infiltration anesthesia and continuous femoral block

Background and purpose Pain after total knee arthroplasty (TKA) is usually severe, and epidural analgesia or femoral nerve block has been considered to be an effective pain treatment. Recently, local infiltration analgesia (LIA) has become increasingly popular but the outcome of this method regarding the analgesic effect has not been fully evaluated. We compared local infiltration analgesia and femoral block with regard to analgesia and morphine demand during the first 24 h after TKA. Methods 40 patients undergoing TKA under spinal anesthesia were randomized to receive femoral nerve block (group F) or peri- and intraarticular infiltration analgesia (group LIA) with a mixture containing ropivacaine, ketorolac, and epinephrine. All patients had access to intravenous patient-controlled analgesia (PCA) with morphine postoperatively. Pain intensity at rest and upon movement was assessed on a numeric rating scale (0–10) on an hourly basis over 24 h if the patients were awake. Results The average pain at rest was marginally lower with LIA (1.6) than with femoral block (2.2). Total morphine consumption per kg was similar between the 2 groups. Ancillary analysis revealed that 1 of 20 patients in the LIA group reported a pain intensity of > 7 upon movement, as compared to 7 out of 19 in the femoral block group (p = 0.04). Interpretation Both LIA and femoral block provide good analgesia after TKA. LIA may be considered to be superior to femoral block since it is cheaper and easier to perform.

Acute hemiarthroplasty after proximal humerus fracture in old patients. A retrospective evaluation of 18 patients followed for 2-7 years

We evaluated the outcome of acute shoulder hemiarthroplasty in 18 patients following displaced three- and four-part fractures of the proximal humerus. The mean age of the patients was 82 (70-92) years and the average follow-up time was 3.5 (2-7) years. No revision due to loosening was performed. All patients were evaluated concerning activities of daily living, degree of pain (VAS-scale, 0-100 mm) and range of motion. The patients had a low functional level, but were able to sleep on the operated side and keep up their hobby. 11 patients were painfree and the worst pain recorded was 28 mm. Range of motion for all movements, except extension, was statistically significant lower than for the non-operated side. We conclude that in elderly patients acute hemiarthroplasty following three- or four-part fractures of the proximal humerus results in good pain relief, but a more limited range of motion than that reported for younger patients.

Operative versus nonoperative treatment of displaced intra-articular calcaneal fractures: a prospective, randomized, controlled multicenter trial.

BACKGROUND We conducted a prospective, randomized, controlled multicenter trial to compare operative with nonoperative treatment of displaced intra-articular calcaneal fractures. METHODS Eighty-two patients who presented to five trauma centers from 1994 to 1998 with an intra-articular calcaneal fracture with ≥2 mm of displacement (as verified by computed tomography) were randomized to operative or nonoperative treatment. Independent observers followed the two groups radiographically and clinically at one year and eight to twelve years. The primary outcome measures were a visual analog scale (VAS) for pain and function and the self-administrated Short Form (SF)-36 general health outcome questionnaire. The secondary outcome measures were residual pain evaluated with a VAS, the American Orthopaedic Foot & Ankle Society (AOFAS) scale, and the Olerud-Molander (OM) scale. RESULTS Forty-two patients in the operative treatment group and forty in the nonoperative group were included. The two groups were comparable with respect to age, sex, and fracture types. Seventy-six patients were available for follow-up at one year and fifty-eight at eight to twelve years. The primary and secondary outcome measures did not differ significantly between the two treatment groups at one year of follow-up. At eight to twelve years of follow-up, there was a trend toward better scores on the patient-reported primary VAS score for pain and function (p = 0.07) and the physical component of the SF-36 (p = 0.06) in the operative group. The prevalence of radiographically evident posttraumatic subtalar arthritis was lower in the operative group (risk reduction, 41%). CONCLUSIONS Operative treatment was not superior in managing displaced intra-articular calcaneal fractures at one year of follow-up but appeared to have some benefits at eight to twelve years. Operative treatment was associated with a higher risk of complications but a reduced prevalence of posttraumatic arthritis evident on follow-up radiographs. LEVEL OF EVIDENCE Therapeutic level II. See instructions for authors for a complete description of levels of evidence.

Decrease of RA-related orthopaedic surgery of the upper limbs between 1998 and 2004: data from 54 579 Swedish RA inpatients

OBJECTIVES To describe the overall use and temporal trends in orthopaedic upper limb surgery associated with RA on a nation wide basis in Sweden between 1998 and 2004. METHODS Data for all inpatient visits during 1998-2004 for patients older than 18 yrs with RA-related diagnoses were extracted from the Swedish National Hospital Discharge Registry (SNHDR). The SNHDR prospectively collects data on all hospital admissions in Sweden according to the International Classification of Diseases (ICD). Data were analysed with respect to orthopaedic surgery of the hand, elbow and shoulder. RESULTS During the study period, 54,579 individual RA patients were admitted to a Swedish hospital and 9% of these underwent RA-related surgery of the upper limbs. The RA patient cohort underwent a total of 8251 RA-related upper limb surgical procedures. The hand (77%) was most frequently operated on, followed by the shoulder (13%) and the elbow (10%). There was a statistically significant decrease of 31% for all admissions associated with RA-related upper limb surgery during 1998-2004 (P = 0.001). Some 10% of all RA-related upper limb surgery was due to total joint arthroplasties (TJAs), mostly for the elbow (59%). During 1998-2004, all TJAs, elbow-TJAs and shoulder-TJAs had a stable occurrence. In contrast, the overall numbers of hand-TJAs significantly increased (P = 0.009). CONCLUSIONS Rates of RA-related upper limb surgery decreased and TJAs had a stable occurrence in Sweden during 1998-2004. The findings of this study may reflect trends in disease management and health outcomes of RA patients in Sweden.

Passive knee muscle moment arms measured in vivo with MRI

OBJECTIVE: To determine moment arm lengths from seven knee muscles and the patellar tendon. The knee muscles were the biceps femoris, semitendinosus, semimembranosus, gracilis, sartorius, and the lateral and medial gastrocnemius muscles. DESIGN: The moment arms were calculated based on MRI measurements. BACKGROUND: Moment arm lengths of different muscles with respect to the joint centre of rotation (CR) or the centre of the contact point between joint surfaces are necessary basic data for biomechanical models predicting joint load. METHODS: Ten male and seven female subjects participated. Using a 1.5 Tesla magnetic resonance imaging system, 3-dimensional coordinates of relevant points were recorded from a 3-D volume reconstruction of the right knee at knee flexion angles of 0, 30 and 60 degrees. Muscular moment arms were calculated in both the sagittal and frontal planes. The recordings were all made during passive mode, which means that no muscular contraction was performed. RESULTS: All muscles except the lateral gastrocnemius showed statistically significant differences (P<0.05) of moment arm lengths between gender in the frontal plane. All muscles except biceps femoris and sartorius showed significant differences (P<0.05) of moment arm lengths between gender in the sagittal plane. Most muscles also showed a linear or quadratic trend of changing moment arms with varying knee angle. CONCLUSIONS: Our results indicate that for most biomechanical analyses involving knee muscles, gender- and angle-specific moment arms should be used.

Tibiofemoral contact points relative to flexion angle measured with MRI.

OBJECTIVE To determine whether knee flexion influenced bony contact movements during flexion. DESIGN Accurate three-dimensional (3D) measurements of tibiofemoral bony contact points in vivo was performed using magnetic resonance imaging technology at 0 degrees, 30 degrees and 60 degrees of flexion. BACKGROUND Magnetic resonance imaging is an accurate non-invasive tool for visualizing muscles, tendons, and bone, and provides precise 3D co-ordinates. METHODS Magnetic resonance imaging recordings were made from the right knee of 16 subjects with no history of knee dysfunction at 0 degrees, 30 degrees and 60 degrees of flexion. Joint contact movements were reported as changes of the contact points position on the medial and lateral tibial condyle with respect to a fixed reference point for each flexion angle. RESULTS The dominant motion of the centroid of the contact area was posterior with a concomitant inferior and lateral displacement when flexing from 0-30 degrees. Increased flexion to 60 degrees the contact points moved slightly anterior, superior and continued laterally. Comparing movements between the medial and lateral compartments, larger displacement magnitudes were observed laterally. Additionally, tibial rotations of 3-5 degrees were noted relative to the femur. CONCLUSION Based on magnetic resonance imaging co-ordinates and the rotated anatomical reference frame, the geometric equations to derive the contact point between the tibiofemoral articulating surfaces is a viable means to investigate tibiofemoral bony contact movement. RELEVANCE Contact areas and pressure distributions have been reported using cadaveric specimens but interpretation of the results is limited. Other investigations have been restricted to sagittal plane movement. Using kinematic magnetic resonance imaging, accurate non-invasive 3D recordings of the normal knee at increments of flexion are possible. The normative baseline date can be compared against that of the pathological knee, such as cruciate ligament injury or the status of post-operative meniscectomy in order to examine skeletal joint motion and stability.

Assessment of functional knee bracing: an in vivo three-dimensional kinematic analysis of the anterior cruciate deficient knee.

OBJECTIVE To describe three-dimensional tibial and femoral movements in vivo and examine the effect of a brace on knee kinematics during moderate to intense activity. DESIGN Skeletal kinematics of anterior cruciate ligament deficient knees was measured with and without braces during moderate to intense activity. BACKGROUND Invasive markers implanted into the tibia and femur are the most accurate means to directly measure skeletal motion and may provide a more sensitive measure of the differences between brace conditions. METHODS Steinmann traction pins were implanted into the femur and tibia of four subjects having a partial or complete anterior cruciate ligament rupture. Non-braced and braced conditions were randomly assigned and subjects jumped for maximal horizontal distance to sufficiently stress the anterior cruciate ligament. RESULTS Intra-subject peak vertical force and posterior shear force were generally consistent between conditions. Intra-subject kinematics was repeatable but linear displacements between brace conditions were small. Differences in angular and linear skeletal motion were observed across subjects. Bracing the anterior cruciate ligament deficient knee resulted in only minor kinematic changes in tibiofemoral joint motion. CONCLUSION In this study, no consistent reductions in anterior tibial translations were observed as a function of the knee brace tested. Relevance. Investigations have reported that knee braces fail when high loads are encountered or when load is applied in an unpredictable manner. Questions remain regarding tibiofemoral joint motion, in particular linear displacements. The pin technique is a means for direct skeletal measurement and may provide a more sensitive measure of the differences between brace conditions.