Healthy middle-aged Asian and Caucasian populations present with large intra- and inter-individual variations of lower limb torsion.

PURPOSE: There is a lack of standardization in the measurement of lower limb torsional alignment. Normal values published in the literature are inconsistent. A 3D-CT-scan-based method was used in a healthy population to define the femoral neck version (FNV) and the tibial torsion (TT) and their relationship with demographic parameters. The study objectives were (1) to define normal values of lower limb torsional alignment, (2) to estimate inter- and intra-individual variations of torsional deformity of healthy individuals' lower limbs. The hypothesis was that FNV and TT values would be influenced by patient characteristics such as gender, age, and ethnicity, and would have low side-to-side asymmetry. METHODS: Torsional landmarks of the lower limbs from 191 healthy subjects were automatically calculated with a 3D CT-scan-based program. The FNV was defined by the angle between the femoral neck axis and the femoral posterior condylar line. The TT angle was considered between the tibial plateau axis and the axis of the ankle. For the former, two alternatives were considered: the line connecting the more medial and lateral point of the medial and lateral plateau, respectively (method 1; TT1), or the line connecting the two more posterior points of the medial et lateral plateau (method 2; TT2). The ankle axis was defined as the line connecting the medial and lateral malleoli. These reference lines were automatically calculated. Age, gender, ethnic group, and BMI were recorded for every subject. A p value < 0.05 was considered as statistically significant. RESULTS: Overall, the mean FNV was 15.3 ± 9.5° and the mean TT was 31.6 ± 6.3°. Female hips were more anteverted than male hips. Caucasians had less anteverted hips than Asians, but more externally rotated tibias. Age and BMI were not correlated with any anatomical parameter. A substantial side-to-side asymmetry was found for FNV [absolute difference (AD) = 6.3°; percentage of asymmetry (%As) = 47%], TT1 (AD = 3°; %As = 12%), and TT2 (AD = 4.9°; %As = 9%) (p = 0.008). CONCLUSION: The findings showed that lower limb torsional parameters were highly variable from patient to patient and from one leg to the other for the same patient. The understanding of normal values concerning femoral version and external tibial torsion in the present healthy population will help surgeons to define pathological values of FNV and TT, as well as corrections to perform in case of torsional deformities. LEVEL OF EVIDENCE: Level III.

Unicompartmental knee replacement after high tibial osteotomy: Invalidating a contraindication.

The outcome of high tibial osteotomy (HTO) deteriorates with time, and additional procedures may be required. The aim of this study was to compare the clinical and radiological outcomes between unicompartmental knee replacement (UKR) and total knee replacement (TKR) after HTO as well as after primary UKR. A total of 63 patients (63 knees) were studied retrospectively and divided into three groups: UKR after HTO (group A; n = 22), TKR after HTO (group B; n = 18) and primary UKR (group C; n = 22). The Oxford knee score (OKS), Knee Society score (KSS), hip-knee-ankle angles, mechanical axis and patellar height were evaluated pre- and post-operatively. At a mean of 64 months (19 to 180) post-operatively the mean OKS was 43.8 (33 to 49), 43.3 (30 to 48) and 42.5 (29 to 48) for groups A, B and C, respectively (p = 0.73). The mean KSS knee score was 88.8 (54 to 100), 88.11 (51 to 100) and 85.3 (45 to 100) for groups A, B and C, respectively (p = 0.65), and the mean KSS function score was 85.0 (50 to 100) in group A, 85.8 (20 to 100) in group B and 79.3 (50 to 100) in group C (p = 0.48). Radiologically the results were comparable for all groups except for patellar height, with a higher incidence of patella infra following a previous HTO (p = 0.02).

Stress radiographs of the patellofemoral joint.

Patellar instability is usually diagnosed on the basis of the clinical presentation without radiographic confirmation. In the present report, we describe a new radiographic method to demonstrate patellar instability. Axial radiographs were made of the patellofemoral joint of ninety individuals (180 knees) and were then repeated while a medial or lateral force was applied to the patella. The applied force was kept constant with use of a specially designed instrument. The ninety individuals were divided into four groups on the basis of the clinical findings: normal, lateral instability, medial instability, and multidirectional instability. Stress radiographs differentiated the four groups and confirmed the clinical diagnosis in all patients who had unilateral symptoms. A four-millimeter increase in medial or lateral excursion of the patella excursion of the asymptomatic knee was significant (p < 0.0001). Stress radiographs offer a simple method for the measurement of force-displacement relationships in the patellofemoral joint and for the demonstration of patellofemoral instability.

Synovial thickening detected by MR imaging in osteoarthritis of the knee confirmed by biopsy as synovitis.

Previous studies have established the value of magnetic resonance imaging (MRI) in detecting articular changes characteristic of osteoarthritis (OA) of the knee. We have observed some MRI features in OA of the knee presumably indicating synovial thickening. To determine whether these MR features represent chronic synovial inflammation, we studied the knees of nine patients at the mild end of the spectrum of OA of relatively short duration (89%: < or = 4 yr), who were selected because MRI showed anatomical abnormalities compatible with synovial thickening. The painful knee was examined using conventional and weight-bearing radiographs, MRI, and arthroscopy. MR images suggestive of synovial thickening typically appeared in or near the intercondylar region of the knee, in the infrapatellar fat pad, or in the posterior joint margin. The site of an arthroscopic biopsy of the synovial membrane was guided by MRI to the area thought to represent synovial thickening for each patient knee. Pathological examination of these synovial membrane biopsies showed a mild chronic synovitis, and thus a correspondence with the synovial thickening detected by MRI. Our results suggest that MRI can be used to evaluate the extent of synovitis, observed as synovial thickening, in patients with early OA of the knee.

Factors affecting articular cartilage thickness in osteoarthritis and aging.

OBJECTIVE: To test the hypothesis that both aging and osteoarthritis (OA) contribute to the variance of human articular cartilage thickness of the knee and whether these contributions occur predominantly at weight bearing cartilage sites. METHODS: Thin, sagittal magnetic resonance images (MRI) of both knees were examined in 52 patients with idiopathic OA of the knee of short duration (87%: < or = 4 years) and 40 reference subjects of comparable age and sex distribution. Articular cartilage thickness was measured at the weight bearing and nonweight bearing femoral condylar, tibial plateau, and posterior patellar sites. Multiple regression analyses were performed to examine the influence of OA, age, sex, obesity (body mass index), and bone size on cartilage thickness. RESULTS: Age accounted for a significant linear decrease (p < 0.001) in both lateral and medial weight bearing femoral cartilage thickness of both knees, but failed to account for any significant variance in thickness at other cartilage sites. OA accounted for a significant decrease (p < 0.02) in the thickness of the femoral articular cartilage in the medial and lateral right knee compartments and in the lateral left knee compartment, but not in the medial left knee compartment. Significant cartilage thinning could be detected by MRI in patients with OA, even when the joint space was normal radiographically. CONCLUSION: The asymmetric decrease in the left knee may reflect the effect of mechanical factors. Our data show that articular cartilage thickness decreases at the femoral weight bearing sites both with age and as a consequence of OA and that these contributions can be distinguished from one another.

MR features of osteoarthritis of the knee.

A group of patients with idiopathic osteoarthritis (OA) of the knee was surveyed using weight-bearing radiographs and MR imaging to compare the relative value of these methods in disease evaluation. Fifty-two patients with a clinical and radiological diagnosis of OA of the knee of relatively short duration (87%: < or = 4 yr) were compared to a reference group of 40 age- and sex-comparable subjects with no knee symptoms. All patients had a complete history, physical examination, standard anterior-posterior and lateral weight-bearing radiographs, T1-weighted, and FLASH MR images in both knees. The prevalence of MRI abnormalities was significantly greater in patients with OA of the knee in all radiographic grades (Kellgren and Lawrence) compared to the reference subjects. Significant differences were encountered for synovial thickening (OA, 73%; reference, 0%), synovial fluid (60%; 7%), meniscal degeneration (52%; 7%), osteophytes (67%; 12%), and subchondral bone involvement (65%; 7%), even in the patients at the mild end of the osteoarthritic spectrum, indicating the exquisite sensitivity of MRI compared with weight-bearing radiographs.

The quantitative measurement of normal passive medial and lateral patellar motion limits.

To quantify normal motion, medial and lateral passive patellar motion limits were measured in 67 high school athletes randomly selected from a group of 1340 athletes undergoing preseason physical examinations. Patellar displacement was measured at knee flexion angles of 0 degree and 35 degrees, using both a Patella Pusher (a hand-held force gauge) and a manual technique, and the results were compared. Demographic data and physical examination of the deceleration mechanism (Q angle, vastus medialis obliquus dysplasia, patella alta and baja, and valgus and varus alignment) were correlated with patellar motion limits. With the knee in extension, passive displacement of the patella averaged 9.6 mm medially and 5.4 mm laterally. In flexion, medial displacement averaged 9.4 mm and lateral displacement averaged 10.0 mm. No positive correlations were found between demographic data or deceleration mechanism examination parameters and patellar motion limits, suggesting that motion produced by the displacement force was limited by ligamentous restraints only. The clinical assessment of the passive limits of patellar motion should include examination at knee flexion angles of 0 degree and 35 degrees. The manually produced displacement was found to be more reproducible than displacement by the Patella Pusher (P < 0.05).

Medial dislocation of the patella.

Medial dislocation of the patella is a previously unreported entity. This disorder can be disabling to the patient and may require a hospital visit for reduction. Three cases are presented in this article in which computed tomography demonstrated the dislocation. All three patients had undergone a lateral retinacular release to the involved knee for treatment of chronic knee pain or recurrent lateral patellar subluxation.

Preoperative planning for the treatment of nonunions and the correction of malunions of the long bones.

A detailed analysis of the steps of preoperative planning as employed in our clinic has been presented. We have found these techniques to be of great value in anticipating the requirements that must be fulfilled to correct malalignments and obtain healing when the malalignments occur alone or are associated with nonunion. Besides helping one to decide where a malalignment is best corrected to anatomically match the normal extremity, tracings aid in allowing the surgeon to appreciate the kinetics of the operative procedure, as well as to define the best methods of stabilizing the resulting correction.

Magnetic resonance imaging of meniscal degeneration in asymptomatic knees.

Histopathological studies have suggested that spontaneous degeneration of knee menisci predisposes to symptomatic tears. We used magnetic resonance (MR) imaging to study noninvasively 20 patients with documented meniscal tears in one knee but asymptomatic contralateral knees, 18 normal controls, and 15 patients with symptomatic nonmeniscal knee disorders. A scoring system for MR signal changes was developed, and differences between the three groups were tested for significance by a multivariate analysis of covariance. MR signal changes in the menisci begin at around 30 years of age, progress with age, occur in both men and women, and occur in subjects who are inactive as well as those who undergo habitual knee stress exercises. Most subjects with documented meniscal tears in one knee have MR signals in the asymptomatic contralateral knee that reflect a more advanced degree of meniscal degeneration than in age-comparable normal controls or patients with nonmeniscal knee disorders. After adjustment for potential confounding variables, weight, and sex, the mean scores in the asymptomatic knee of patients with meniscal disease are significantly higher than those of normal controls (p = 0.021) and nonmeniscal disease patients (p = 0.019). These results document the occurrence of age-dependent degeneration within knee menisci, and support the hypothesis that a segment of the population has pre-existing meniscal degeneration predisposing them to traumatic or spontaneous meniscal tears.

Rupture of the distal insertion of the biceps brachii tendon.

Rupture of the distal insertion of the biceps brachii tendon is a rare injury. There has been no unanimity in the literature concerning the best method of repair. Between March 1981 and July 1984, 14 ruptures (12 acute and two late) were repaired using a modification of the Boyd-Anderson technique. Cybex testing of the elbow flexion by applying an eccentric load demonstrated that strength and endurance in the repaired dominant arm were roughly equal to the noninjured, nondominant arm, but that strength and endurance of the repaired nondominant arm were only 64% and 50%, respectively, of the noninjured dominant arm. Surgical repair is a safe procedure that yields consistently good results.

Ambulation in severe arthrogryposis.

Functional ambulation occurred in 22 of 36 severely affected arthrogrypotic patients. Functional ambulation in these patients required hip motion to within 30 degrees of full extension and knee motion to within 20 degrees of full extension. Ambulation also required hip extensor strength of good (grade 4), quadriceps strength of fair (grade 3), or crutchable upper extremities and orthotic substitutes. Foot and spine deformities also interfered with ambulatory ability.