Development of new cartilage lesions after ACL reconstruction is associated with abnormal knee rotation.

PURPOSE: The purpose of this study is to examine the association between the development of articular cartilage pathology and knee rotation after single-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: Seventeen patients that underwent single-bundle ACL reconstruction and did not have any cartilage lesions at the time of surgery based on the Outerbridge classification or meniscal injury that required meniscectomy > 20% were examined by MRI and in the biomechanics laboratory at a 6-year minimum follow-up. Cartilage lesions that occurred after reconstruction were graded on MRI according to a modified Noyes scale. For cartilage evaluation, the lateral and medial femoral condyles were divided into 9 segments each (lateral, central, and medial third and each third was divided into anterior, central, and posterior segment). Tibial rotation during a pivoting task was measured with optoelectronic motion analysis system and side-to-side differences of tibial rotation between the reconstructed and contralateral intact knees were calculated. The association between the total modified Noyes scale score (outcome variable) and side-to-side differences of tibial rotation after controlling for meniscectomy and meniscal repair was investigated with hierarchical regression models. RESULTS: Side-to-side difference of tibial rotation was associated with total modified Noyes scale score (p = 0.015, ß = 0.667, adjusted R2 = 42.1%). All patients developed new cartilage lesions in MRI located mainly at the central region of the lateral femoral condyle and less frequently in the central and anterior regions of the medial femoral condyle. CONCLUSION: Abnormally increased tibial rotation that persists after ACL-R is significantly associated with the development of new articular cartilage lesions at mean 8.4 years after reconstruction which were located mainly at the central region of the LFC and secondarily in the central and anterior regions of the MFC (more superficial lesions). These findings suggest that there is emerging evidence that abnormal rotational kinematics is a potential risk factor for the pathogenesis and onset of posttraumatic articular cartilage degeneration after ACLR. LEVEL OF EVIDENCE: IV.

Kinematic and Kinetic Waveform Changes of the Knee Joint Following a Mobile Bearing Total Knee Arthroplasty-Gait Analysis and Single Step Ascent.

The objective of this study is to analyze the kinetic and kinematic changes of the osteoarthritic knee after a mobile bearing total knee arthroplasty. Kinematic and kinetic gait analysis of level walking was performed in 15 patients (eight female and seven male) with knee ostoarthritis. All patients were free of any neurological diseases that could affect their normal gait. Mean age was 68.6 ± 5.2 years, mean height 159.8 ± 6.9 cm, and mean weight was 78.5 ± 10.1 kg. Full body gait analysis was performed using the BioKin three-dimensional (3D) motion analysis system preoperatively and 9 months after total knee arthroplasty. A single-step ascending kinetic analysis and a plantar pressure distribution analysis were also performed in all patients. An increased average cadence (mean 99.39 step/min preoperatively and 104.64 step/min postoperatively; p = 0.152), step length (0.44 m preoperatively and 0.52 m postoperatively; p < 0.001), stride length (0.89 m preoperatively and 1.0 m postoperatively; p < 0.007), and walking velocity (0.73 m/sec preoperatively and 0.90 m/sec postoperatively; p = 0.005) were noted postoperatively and postoperatively. A decrease in the stance duration percentage and the knee adduction moment was also reported postoperatively. All patients showed a significant improvement of knee kinetics and kinematics after a mobile bearing total knee arthroplasty. Statistically significant differences were found in the step length, stride length, and walk velocity postoperatively. The knee adduction moment was also significantly reduced. Further research is warranted to determine the clinical relevance of these findings. This study is a prospective comparative one and reflects level II evidence.

Differences of bone mineral mass, volumetric bone mineral density, geometrical and structural parameters and derived strength of the tibia between premenopausal and postmenopausal women of different age groups: a peripheral Quantitative Computed Tomography (pQCT) study.

Menopause constitutes a significant cause of bone loss, and it is currently debated whether bone mass is preserved or begins to decline substantially before that time in women. We used pQCT of the tibia to estimate differences of bone mineral mass, bone geometry and derived strength between premenopausal and postmenopausal Caucasian women of different age-groups per decade of age (20-79y). For each individual, we assessed total, trabecular and cortical bone mineral content (BMC, mg) and volumetric bone mineral density (BMD, mg/cm3); total and cortical cross-sectional areas (CSA, mm2); periosteal circumference (PERI_C, mm); endosteal circumference (ENDO_C, mm); mean cortical thickness (CRT_THK, mm); and Stress-Strain Index (SSI) . Comparisons were made both between premenopausal (N=84) and postmenopausal (N=231) women as distinct groups, and among women of the different age-groups. Our results indicated that premenopausal women had significantly higher trabecular and cortical BMC and vBMD, with higher cortical CSA, CRT_THK and SSI than postmenopausal women. Moreover, significant differences of trabecular but not cortical BMC, vBMD or SSI were found between women of the younger (<48y) age-groups. PERI_C, ENDO_C displayed lower values in the 20-29y group and higher values in the 70-79y group, denoting significant differences of bone geometry with aging.

Anterior-Posterior Instability of the Knee Following ACL Reconstruction with Bone-Patellar Tendon-Bone Ligament in Comparison with Four-Strand Hamstrings Autograft.

Purpose. To evaluate anterior-posterior knee laxity using two different autografts. Material-Methods. 40 patients, (34 males and 6 women), 17-54 years old (mean: 31), were included in the present study. Group A (4SHS = 20) underwent reconstruction using four-strand hamstrings, and group B (BPBT = 20) underwent reconstruction using bone-patellar tendon-bone autograft. Using the KT-1000 arthrometer, knee instability was calculated in both knees of all patients preoperatively and 3, 6, and 12 months after surgery at the ACL-operated knee. The contralateral healthy knee was used as an internal control group. Results. Anterior-posterior instability using the KT1000 Arthrometer was found to be increased after ACL insufficiency. The recorded laxity improved after arthroscopic ACL reconstruction in both groups. However, statistically significant greater values were detected in the bone-patellar tendon-bone group, which revealed reduction of anteroposterior stability values to an extent, where no statistical significance with the normal values even after 3 months after surgery was observed. Conclusions. Anterior-Posterior instability of the knee improved significantly after arthroscopic ACL reconstruction. The bone-patellar tendon-bone graft provided an obvious greater stability.

Influence of acute anterior cruciate ligament deficiency in gait variability.

The objective of this study was to compare the gait variability of patients with isolated anterior cruciate ligament (ACL) deficiency (experimental group) with that of healthy individuals (control group). The hypothesis was that the gait variability of the experimental group would be higher than the control group. The experimental group consisted of 20 men with an ACL tear and the control group consisted of 20 healthy men without any neurological and/or musculoskeletal pathology or injury. The gait acceleration signal was analysed using the Gait Evaluation Differential Entropy Method (GEDEM). The GEDEM index of the experimental group in the medio-lateral axis was significantly higher than that of the control subjects. A receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of the method and to determine a cut-off entropy value. The GEDEM cut-off value had a 95.6% probability of separating isolated ACL patients from healthy subjects.

[MRI evaluation of meniscal movement and deformation in vivo under load bearing condition]. / Kernspintomographische Untersuchung der Meniskusbeweglichkeit und -deformation in vivo unter Gewichtsbelastung.

AIM: The aim of this experimental study was a quantitative evaluation of meniscal movement and deformation in vivo under load bearing conditions. METHODS: Sagittal T1-weighted MRI pictures of 15 healty knees were evaluated. The subjects were placed in an open MRI, that enabled measurements under load bearing and in different flexion grades. Series of pictures of the medial and lateral meniscus without load, with half and full body weight load and in full extension and 30 degrees flexion were taken. Two examiners measured twice the height of the posterior horn, and the inner and outer distance between the anterior and posterior horns of the menisci. RESULTS: The height of the posterior horns of the medial and lateral menisci decreased with increasing load. The inner and outer distance increased with load, the inner distance more than the outer, resulting in a compression of the periphery. Increase of flexion from 0 degrees to 30 degrees significantly influenced only the outer distance of both menisci. CONCLUSION: This method can be used in future to functionally evaluate the postoperative result after meniscus saving or replacing therapies. The compression of meniscal periphery from the inside to the outside under load in full extension allows early postoperative mobilisation after meniscal sutures.

[Internal rotational strength of the thigh after ACL reconstruction. Prospective comparison of harvesting of the semitendinosus and gracilis tendons and the patella tendon]. / Innenrotationskraft des Unterschenkels nach Kreuzbandrekonstruktion. Prospektiver Vergleich zwischen Entnahme der Semitendinosus- und Grazilissehnen und der Patellasehne.

AIM: The aim of the present study was the prospective, randomized evaluation of the internal rotation strength in patients, undergoing ACL reconstruction using either semitendinosus and gracilis tendon autografts (ST/G) or the central third of the patella tendon (BPT). METHOD: 40 patients (20 male, 20 female, average age 32 years [16 - 49]) underwent reconstruction of the ACL. In 20 patients ST/G was used, in 20 matched patients the central third of the patella tendon (BPT) was used. Rehabilitation was identical for both groups. The isometric strength of internal tibial rotation in neutral position was measured preoperatively, 3, 6 and 12 months postoperatively. RESULTS: After 3 months no difference to the preoperative data was found. After six months the internal tibial torque was significantly higher (p < 0.05) than preoperatively. No additional increase was found after 12 months. There was no statistically significant difference between both groups at any time. CONCLUSION: The internal tibial torque, which is predominantly a function of the pes anserinus, recovers shortly after operation and is, due to postoperative rehabilitation, significantly elevated after 6 months. The randomized comparison with the harvesting of the central third of the patellar tendon showed no significant difference.

Computed tomography-guided endoscopic removal of an osteoid osteoma from the femur.

The case of a 19-year-old male patient who complained of dull pain in his right knee for more than 18 months and was finally diagnosed with intracortical osteoid osteoma in the femoral diaphysis is presented. A new operative method was used to locate and remove the tumor. Under spinal anesthesia with the patient in the prone position, a lateral and a posterior approach were marked with special bone cutting tubes under computed tomographic control. The usual arthroscopic instruments (punch, retrograde suction stamp) were used to remove the nidus under arthroscopic visualization, thereby avoiding the disadvantages of open excisions, such as large incisions, bone loss, long hospitalization, and risk of infection. The advantages and disadvantages are thoroughly discussed and compared with conventional surgical procedures.