The effect of femoral component position on the kinematics of total knee arthroplasty

In a laboratory study using seven fresh-frozen anatomic specimen knees, the effect of total knee arthroplasty on the three-dimensional kinematics of the patella, femur, and tibia were measured. Experiments were performed in the intact knee, after division of the anterior cruciate ligament (ACL), after total knee arthroplasty, and after 10 degrees internal rotation, 10 degrees external rotation, 5-mm medial shift, and 5-mm lateral shift of the femoral component on the femur. The presence of a high lateral ridge on the anterior surface of the femoral component effectively prevented patellar subluxation or dislocation, but displaced and tilted the patella medially. Internal rotation or medial displacement of the femoral component exaggerated this medial patellar displacement and shift. External rotation of the femoral component corrected it, except at flexion angles greater than 100 degrees, where the femur was shifted medially on the tibia and externally rotated 15 degrees. This combination produced a net 10-mm medial displacement of the patella relative to the tibia at 120 degrees knee flexion. Lateral placement of the femoral component compensated for the effect of the high lateral ridge and allowed more normal patellar tracking while allowing tibiofemoral motions similar to those seen after sectioning of the ACL. The kinematics of the patellofemoral and tibiofemoral joints were not reproduced with a total knee prosthesis that sacrifices the ACL. When using a prosthesis with a high lateral ridge, lateral placement of a femoral component prevented patellar dislocation and allowed patellar tracking patterns similar to those seen in the intact knee without further altering tibiofemoral motions.     

Reproducibility of knee laxity assessment results using the dynamic cruciate tester

The purpose of the study was to examine reproducibility of knee laxity measurements obtained using the Dynamic Cruciate Tester (DCT) from day-to-day, set-to-set, and trial-to-trial. In Part I, peak anterior tibial translation (ATT) was assessed for 1 anterior cruciate ligament (ACL) deficient and 16 control subjects during two sets of three active trials (maximal isometric quadriceps contractions) and three passive trials (240 N load) conducted over four consecutive days. In Part II, peak ATT was recorded for 12 chronic ACL deficient subjects during one set of five active and five passive trials within one day. Results were analysed using mixed repeated measures ANOVA designs with intraclass reliability coefficients (ICC) calculated from the ANOVA results. There were no significant differences in the mean peak ATT results among the four tests days or between the two test sets conducted within a day, with ICC ranging from R1 = 0.939 to 0.980. It was concluded peak ATT measurements obtained using the DCT were reproducible from day-to-day and set-to-set. A significant main effect of trial was found on both active (F(2,32) = 13.93; p < 0.001) and passive (F(2,32) = 57.21; p < 0.001) peak ATT results. It was therefore recommended a full pretrial should be conducted before knee laxity assessment using the DCT to ensure reproducible results.     

Anterior knee laxity and loss of extension after anterior cruciate ligament injury

This study was performed to examine the relationship between knee extension loss and the length of time after injury. We also wanted to compare anterior laxity in anterior cruciate ligament-injured knees in the early and late stages of injury. Loss of knee extension was measured in 81 patients with anterior cruciate ligament injury using lateral radiography with the injured leg relaxed and elevated. Extension loss was defined as the difference in maximal extension angle between the injured and uninjured knees. Average loss of extension was 3.6 degrees in the 17 knees in which the anterior cruciate ligament had been torn 3 weeks or less before examination (the acute injury group) and 0.6 degree in the 64 knees in which the anterior cruciate ligament had been torn more than 3 weeks before examination (the chronic injury group). The extension loss in the acutely injured knees was significantly greater compared with that in the uninjured knees and in the chronically injured knees. Arthrometric measurements using the KT-1000 arthrometer were reliable to diagnose an acute tear. There was no correlation between the degree of extension loss and arthrometric anterior knee laxity measurements. In 12 patients, the initial extension deficit in the early stage of injury significantly resolved with time, and manual maximum arthrometric measurements of anterior knee laxity improved spontaneously with time.     

Analysis of proprioception in the posterior cruciate ligament-deficient knee

Preseptal cellulitis has a typically benign course when treated with antibiotics, the clinical course depending on age of the patient, aetiology and the causative organism. In this study, 14 cases of preseptal cellulitis are documented with the age ranging from 2 to 55 years. The organisms isolated were Staphylococcus aureus (7 cases), Streptococcus pyogenes (2 cases) and Pseudomonas aeruginosa (1 case). In the remaining four patients no organism could be identified. All except four patients were cured within 6 weeks. Complications seen included lagophthalmos, lid abscess, cicatricial ectropion and lid necrosis in one patient each. The prognosis for preseptal cellulitis is good with appropriate antibiotics and surgical therapy.     

Role of the posterior cruciate ligament in total knee arthroplasty

Accumulating evidence indicates that protein kinase C (PKC)-dependent, Ca2+-independent smooth muscle contraction plays the central role in the occurrence of chronic vasospasm following aneurysmal subarachnoid hemorrhage. As far as we know, the nitric oxide/ cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) system comprises the most efficacious inhibitory mechanism against the PKC-dependent contractile mechanism, and the myogenic tonus of normal cerebral arteries is thought to be maintained on the balance between these systems. Recent studies indicate that in spastic cerebral arteries, the rise in the intracellular diacylglycerol level causes PKC activation presumably owing to the overexpression of endothelin (ET)-1 as well as the generation of free radicals, whereas the cGMP level is inversely reduced owing to the inactivation of soluble guanylate cyclase through some as yet unknown mechanism. The resultant loss of balance between the two systems is considered to culminate in the occurrence of chronic vasospasm lasting for nearly 2 weeks. Based on the above concept, recent papers concerning the effects of reactive oxygen species on the arterial smooth muscle, alterations of various membrane ion channels, particularly of adenosine triphospate (ATP)-activated potassium channels in spastic arteries, the preventive effects of ET antagonists on vasospasm, and the causative role of ET-1 were reviewed in the present article. The roles of the above spasmogenic factors or mechanisms may be more clearly understood on the basis of the antagonistic interrelation between the PKC and the PKG systems, which exert diverse influences on the force-generating system as well as on its multifarious regulatory mechanisms in smooth muscle cells.     

The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion

OBJECTIVE: To assess the outcome of 31 patients treated in a day and semi-residential psychotherapy setting. METHOD: Patients had moderate to severe personality difficulties and were referred when current therapy was insufficient or because of the severity of their problems. Eighty-one percent had a Cluster C and 19% a Cluster B (Borderline) Personality Disorder diagnosis (DSM-III-R). Therapy was psychodynamically and feministin-formed and included a sociopolitical dimension. Rating scales used were the Symptom Checklist 90, Goal Attainment Scale, Global Assessment Scale and measures of health resource usage, which were completed pre-treatment, post-treatment and at 4-, 12- and 24-month follow-up. RESULTS: Mean duration of therapy was 4 months (68 therapy days). All clinical rating scales demonstrated marked improvements following treatment (p < 0.0001) which were sustained at 2-year follow-up. There were also improvements of health resource usage. CONCLUSIONS: The results document the clinical efficacy of psychotherapy in this setting, provide support for the philosophy of practice, and suggest that psychotherapy outcome can be evaluated at reasonable financial cost in many settings.     

Isolated sectioning of the medial and posteromedial capsular ligaments in the posterior cruciate ligament-deficient knee. Influence on posterior tibial translation

OBJECTIVES: This study examined whether heightened cardiovascular reactivity and low socioeconomic status had synergistic effects on the progression of carotid atherosclerosis in a population of eastern Finnish men. METHODS: Data from the Kuopio Ischemic Heart Disease Risk Factor Study were used to measure 4-year progression of intima-media thickness in 882 men according to cardiovascular reactivity and socioeconomic status. Associations were examined in relation to risk factors and were stratified by baseline levels of atherosclerosis and prevalent ischemic heart disease. RESULTS: The effect of reactivity on atherosclerotic progression depended on socioeconomic status. Men who had heightened cardiovascular responsiveness to stress and were born into poor families, received little education, or had low incomes had the greatest atherosclerotic progression. CONCLUSIONS: An understanding of associations between individual risk factors and disease should be based on etiologic hypotheses that are conceived at the population level and involve fundamental social and economic causes of disease. This study demonstrates how examining the interaction of an individual biological predisposition will low socioeconomic status over the life course is etiologically informative for understanding the progression of atherosclerotic vascular disease.     

Effect of partial release of the posterior cruciate ligament in total knee arthroplasty

Appropriate tension of the posterior cruciate ligament, which often is tight in deep flexion, is difficult to achieve after posterior cruciate ligament retaining total knee arthroplasty. Kinematics and maximum flexion after partial release of the posterior cruciate ligament were evaluated in this study. A partial release improved the maximum flexion angle and maintained anteroposterior stability without causing undesirable changes in kinematics, whereas full resection of the posterior cruciate ligament caused unfavorable anteroposterior instability. Partial posterior cruciate ligament release eliminated excessive rollback movement caused by a tight posterior cruciate ligament and also shifted the point of articular surface contact anteriorly. These results indicate that partial release of the posterior cruciate ligament may improve knee function in patients with a tight posterior cruciate ligament after total knee arthroplasty.     

Anterior cruciate ligament reconstruction. The effect of tibial tunnel placement on range of motion

In 111 patients who had anterior cruciate ligament reconstructions, postoperative radiographic measurements of anterior to posterior and medial to lateral location of the tibial tunnels were correlated with the final range of motion achieved. In the 25 patients with extension deficits of 10 degrees or more, placement of the tibial tunnel was more anterior (average, anterior 23% of the tibia) than in the remaining 86 patients with extension deficits of < 10 degrees (average, anterior 29% of tibia). This difference was statistically significant with P < 0.001. Logistic regression analysis revealed that the more anterior the placement of the tibial tunnel, the greater the loss of both flexion (P = 0.01) and extension (P = 0.002). In the 21 patients with full extension but flexion < 130 degrees, placement of the tibial tunnel tended to be more medial (average, medial 40% of the tibia) than in the 65 patients without flexion deficit (average, medial 45% of the tibia). We conclude that placement of the tibial tunnel in the "eccentric," anteromedial position may contribute to the development of flexion and extension deficits after anterior cruciate ligament reconstruction.     

The effect of exercise and rehabilitation on anterior-posterior knee displacements after anterior cruciate ligament autograft reconstruction

We studied the effect of rehabilitation strength training and return to activities on anterior-posterior knee displacements after patellar tendon autogenous anterior cruciate ligament reconstruction. A total of 938 measurements were sequentially collected for 142 patients with the KT-2000 arthrometer. Rehabilitation included immediate knee motion and early weightbearing, light sports at 6 months, and competitive sports at 8 months or later. At a minimum of 2 years after surgery, 121 patients (85%) had normal displacements (less than 3 mm of increase at 134 N), 14 (10%) had 3 to 5.5 mm of increase (partial function), and 7 (5%) had more than 5.5 mm of increase (failed). There was no association found between the initial onset of the abnormal displacements in the 21 knees and either the amount of time after surgery or the rehabilitation program. Six of the seven grafts that failed did so in the 1st postoperative year. Serial displacement measurements allow early detection of graft stretching and subsequent modification of rehabilitation or delay in return to strenuous activities. These measurements showed that the rehabilitation program used in this study was not itself injurious and resulted in an acceptable failure rate of 5%.     

Bone tunnel enlargement after anterior cruciate ligament reconstruction with semitendinosus tendon using Endobutton fixation on the femoral side

We evaluated 29 knees with a minimum follow-up of 2 years after anterior cruciate ligament (ACL) reconstruction using doubled autogenous semitendinosus tendons. On the femoral side, a 5-mm Mersilene tape (Ethicon, Norderstedt, Germany) with an Endobutton (Acufex Microsurgical, Mansfield, MA) was used. The tendon was fixed on the tibial side with two staples. Regarding the IKDC score, 66% of the patients were graded as normal or nearly normal. The anterior laxity side-to-side difference (KT 1000, man-max-drawer) was under 3 mm in 55% and under 5 mm in 90%. Radiographs taken in the lateral and anteroposterior projections of the knee showed sclerotic bone tunnel margins. The diameter of the bone tunnels were measured, corrected for magnification, then compared with the original reamed diameter to determine any change in size. Enlargement of at least 2 mm was identified in 72% of the femoral tunnels and 38% of the tibial tunnels. No correlation was found concerning the enlargement of the tunnel and the IKDC score or the residual joint laxity. We conclude that using an Endobutton-Mersilene construct in ACL reconstruction leads to femoral and tibial bone tunnel enlargement at follow-up of 2 years.     

Changes in knee kinematics after application of an articulated external fixator in normal and posterior cruciate ligament-deficient knees

Stimulation of DNA and protein synthesis in brown preadipocytes by 1 microM neokyotorphin in serum-containing media was comparable with the effect of 1 microM norepinephrine. In serum-free medium a decrease and a shift of the maximal effect to lower concentration of neokyotorphin were observed. Kyotorphin had no effect on cell proliferation in either medium; however, 0.01-1 microM kyotorphin inhibited the cell proliferation stimulated by 1 microM norepinephrine. Norepinephrine and both peptides stimulated comparable Ca2+ rise in freshly isolated brown preadipocytes. The effects of neokyotorphin and norepinephrine were additive, whereas 0.03-0.3 microM kyotorphin blocked the action of 3 microM norepinephrine. The peptides did not affect the cAMP level in non-stimulated or norepinephrine-stimulated cultured cells. The effects of the peptides on the brown fat cell cultures indicate that peripheral tissue cells contain receptors for these neuropeptides.     

Reconstruction of anterior cruciate ligament using the doubled tendon graft technique: an experimental study in rabbits

BACKGROUND: Mepartricin, a semisynthetic polyene derivative with a favorable effect on urethro-prostatic function, was clinically evaluated, adopting the diagnostic and research criteria recommended by the First International Consultation on BPH. METHODS: A multicenter, randomized, double-blind, parallel-group study compared mepartricin 40 mg/daily to placebo in the treatment of 196 patients with newly diagnosed BPH and mild-to-moderate symptomatology. International Prostate Symptom Score (I-PSS), quality of life (QoL) index and maximum urinary flow-rate (Qmax) were determined every 4 weeks for 6 months; postvoiding volume, prostate volume, and prostate-specific antigen (PSA) were assessed after 3 and 6 months of therapy. RESULTS: Mepartricin was shown to determine a statistically significant improvement over placebo in I-PSS and QoL index from month 2 onwards, and a significant linear increase in Qmax over the study period. At month 6, the improvement in the mepartricin and placebo groups in I-PSS, QoL index, and Qmax was 6.3 (standard error (SE) 0.51) and 4.2 (SE 0.60) points (P = 0.003), 0.99 (SE 0.14) and 0.62 (SE 0.12) points (P = 0.036), and 2.7 (SE 0.46) and 1.2 (SE 0.46) ml/sec (P = 0.051), respectively. No significant differences were noted in postvoiding residual volume, prostate volume, or PSA. Mepartricin tolerability was good, showing no adverse events on sexual function. CONCLUSIONS: Mepartricin proved to be an effective treatment of benign prostatic hyperplasia, determining an improvement in symptoms, quality of life, and peak urinary flow.     

A prospective study of the outcome of anterior laxity of the knee after anterior cruciate ligament reconstruction with procedures using two different patellar tendon grafting methods

Oligonucleotides coding for linear epitopes of the fimbrial colonization factor antigen I (CFA/I) of enterotoxigenic Escherichia coli (ETEC) were cloned and expressed in a deleted form of the Salmonella muenchen flagellin fliC (H1-d) gene. Four synthetic oligonucleotide pairs coding for regions corresponding to amino acids 1 to 15 (region I), amino acids 11 to 25 (region II), amino acids 32 to 45 (region III) and amino acids 88 to 102 (region IV) were synthesized and cloned in the Salmonella flagellin-coding gene. All four hybrid flagellins were exported to the bacterial surface where they produced flagella, but only three constructs were fully motile. Sera recovered from mice immunized with intraperitoneal injections of purified flagella containing region II (FlaII) or region IV (FlaIV) showed high titres against dissociated solid-phase-bound CFA/I subunits. Hybrid flagellins containing region I (FlaI) or region III (FlaIII) elicited a weak immune response as measured in enzyme-linked immunosorbent assay (ELISA) with dissociated CFA/I subunits. None of the sera prepared with purified hybrid flagella were able to agglutinate or inhibit haemagglutination promoted by CFA/I-positive strains. Moreover, inhibition ELISA tests indicated that antisera directed against region I, II, III or IV cloned in flagellin were not able to recognize surface-exposed regions on the intact CFA/I fimbriae.     

The effects of knee reconstruction on combined anterior cruciate ligament and anterolateral capsular deficiencies

We tested the effect of intraarticular reconstructions of the anterior cruciate ligament alone and in combination with extraarticular reconstructions in 10 cadaveric knees. These knees had anterior cruciate ligament deficiency alone or in combination with anterolateral capsuloligamentous deficiencies. In the knees with combined injury, intraarticular reconstruction returned anterior stability to levels not significantly different from levels found for the knees deficient in the anterior cruciate ligament alone and treated with this procedure. After intraarticular reconstruction, rotational stability of the knee with combined injuries failed to return to the levels seen in the knee with isolated anterior cruciate ligament deficiencies that underwent the same treatment. When a tenodesis with either 0 N or 22 N of tension was added to the intraarticular reconstruction in the knee with combined injuries, we found that excessive internal rotation significantly decreased at all angles of flexion, except at full extension with 0 N of tension. In addition, the extraarticular reconstruction with 22 N of tension in the tenodesis overconstrained the knee in internal rotation between 30 degrees and 90 degrees of knee flexion. The tenodesis with 0 N of tension overconstrained the knee at only 60 degrees and 90 degrees of flexion. These results suggest extraarticular reconstruction as an adjunct to the intraarticular operation for the knee with anterior cruciate ligament and anterolateral structural injuries. The results also suggest that the surgeon can affect anterior and rotational laxity by adjusting the tension in the tenodesis.     

A biomechanical study of replacement of the posterior cruciate ligament with a graft. Part II: Forces in the graft compared with forces in the intact ligament

To evaluate the allelic frequency and genetic diversity of alpha-thalassemia defects in Sicily, both epidemiological and patient-oriented studies were carried out. For the epidemiological study, phenotypic data were collected on more than 1000 Sicilian individuals. Among them, 427 were explored at the molecular level for nine alpha-thalassemic variants known to be common in the Mediterranean region. Our data reveal an allele frequency of 4.1% for alpha(+)-thalassemia matching that of beta-thalassemia in this region. The presence of alpha0-thalassemia (--MEDI and --CAL) was observed only in the group of referred patients. Newly acquired nucleotide sequence data on the deletional breakpoint of --CAL allowed us to design a simple PCR-based procedure for exploring this allele. The data also provide additional information concerning the genetic mechanisms involved in such large deletions.     

Meniscal position on routine MR imaging of the knee

OBJECTIVE: To determine the prevalence of meniscal protrusion (i.e. location of the outer edge of a meniscus beyond the tibial articular surface), and to determine its relationship with internal derangement, joint effusion, and degenerative arthropathy. DESIGN AND PATIENTS: Sagittal and coronal MR images of 111 abnormal and 46 normal knees were evaluated for the presence of meniscal protrusion. We set 25% as the minimum amount of displacement considered abnormal because this was the smallest amount of displacement we could confidently discern. Presence of meniscal tear, anterior cruciate ligament (ACL) injury, joint effusion, or osteophytosis was also recorded. RESULTS AND CONCLUSION: Normal examinations demonstrated protrusion of the medial meniscus in 6.5% of sagittal images and 15% of coronal images, and of the lateral meniscus in 2% and 13%, respectively. Fisher's exact test demonstrated a statistically significant difference between the normal and abnormal groups for the medial meniscus on both sagittal (P < 0.0001) and coronal (P = 0.01) images, but not for the lateral meniscus in either plane (P > 0.2). A protruding medial meniscus was associated with effusion and osteophytosis (P < 0.05) but not with meniscal or ACL tear (P > 0.1). Posterior protrusion of the lateral meniscus was only associated with ACL injury (P < 0.0001); protruding anterior horns and bodies of lateral menisci were not associated with any of the four abnormalities. It is concluded that the medial meniscus may occasionally protrude more than 25% of its width, but protrusion is more often due to effusion and osteophytes. Protrusion of the posterior horn of the lateral meniscus is associated with ACL insufficiency, while protrusion of the body and anterior horn of the lateral meniscus is a normal variant.     

Effect of medial displacement of the tibial tubercle on patellar position after rotational malposition of the femoral component in total knee arthroplasty

A large Q angle induced by technical error such as an internally rotated femoral component causes patellar failure after total knee arthroplasty. The effect of medial displacement of the tibial tubercle to decrease the Q angle for patellar tracking was studied by evaluating the patellar position relative to the patellar groove on the femoral component in cadaver specimens. A 5 degrees internally rotated femoral component caused the patella to shift medially about 5 mm, and also caused the tibia to rotate internally about 3 degrees at full extension. With a 5 degrees externally rotated femoral component, normal patellar tracking occurred. The distance of medial displacement was determined so that the patellar tendon was parallel to the longitudinal axis of the tibia at full extension. This allowed the quadriceps tendon, the patella, and the patellar tendon to form a straight line. The average distance of medial transposition of the tibial tubercle was 9.32 mm. Medialization of the tibial tubercle caused the patella to shift about 2 mm medially from the patellar groove. The transfer also caused an external rotation of the tibia (2 degrees-5 degrees). Medial transfer of the tibial tubercle changes patellar kinematics and corrects the tendency toward lateral patellar dislocation caused by internally rotating the femoral component; however, it also creates minor patellar and tibial kinematic changes that may have a clinical effect.