SummaryThis article describes the use of the Hall Effect strain transducer (HEST) in a new arthroscopic technique to study the normal anterior cruciate ligament (ACL) in-vivo. Study participants were patient volunteers with normal ACLs undergoing diagnostic arthroscopic or meniscal surgery under local anaesthesia. The HEST was implanted into the Anterior Medial Band (AMB) of the ACL. Anterior shear loading of the tibia in relation to the fixed femur at 30° of knee flexion (Lachman test), produced significantly greater strain values in comparison to anterior shear loading at 90° (Anterior Drawer test). During isometric quadriceps contraction a significant increase in AMB strain was measured with the knee flexed to 30°, while no significant change was measured at 90°. For quadriceps contraction there were significantly higher values of AMB strain measured at 30° of knee flexion in comparison to that observed at 90°. For active range of motion (AROM) the AMB was strained between 10° and 48°, and unstrained between 48° and 110°. During passive range of motion (PROM) the AMB remained unstrained until the joint was brought into extension. There were significant differences in strain values found between AROM and PROM at the flexion angles 10°, 20°, 30° and 40°, while between 50° and 110° there were no significant differences. These results confirm previous studies that the Lachman test is a superior technique in comparison to the classic anterior drawer test for evaluating the AMB. They suggest that isometric quadriceps activity at 90° of knee flexion can be prescribed for rehabilitation immediately after ACL reconstruction. These data indicate that AROM (between the limits of 50° and 110°) and PROM may also be performed with minimal risk of strain to a reconstructive replacement. The PROM data may also serve as an important standard for the reconstruction of the ACL.RésuméCet article décrit l'utilisation du transducteur de tension par effet Hall (TTEH) dans une nouvelle technique arthroscopique pour étudier le ligament croisé antérieur (LCA) normal in vivo. Les participants à l'étude étaient des patients volontaires avec LCA normal, soumis à une arthroscopie à visée diagnostique ou à une intervention sur un ménisque, sous anesthésie locale. Le TTEH fut implanté dans la bande médiane antérieure (BMA) du LCA. La translation antérieure du tibia, le fémur étant fixé et le genou fléchi à 30° (test de Lachman), donne des chiffres de tension sensiblement plus élevés par rapport à ceux obtenus en flexion à 90° (épreuve de tiroir antérieur). Lors de la contraction isométrique du quadriceps, une augmentation significative de la tension de la BMA a été notée, le genou fléchi à 30°, alors qu'aucune modification n'était mesurable à 90°. Lors des contractions du quadriceps, les chiffres de tension de la BMA, le genou fléchi à 30° étaient notablement supérieurs à ceux enregistrés à 90°. Dans le secteur de mobilité active, la BMA était sous tension entre 10° et 48° et ne l'était pas de 48° à 110°. Durant la mobilisation passive la BMA restait détendue jusqu'à ce que l'articulation soit mise en extension complète. On a trouvé des différences significatives entre les tensions mesurées lors des mobilisations actives et passives aux angles de flexion de 10°, 20°, 30° et 40°, alors qu'il n'y en avait pas de 50° à 110°. Ces résultats confirment les études antérieures selon lesquelles le test de Lachman est une technique d'examen plus sensible que la classique recherche du tiroir antérieur pour évaluer la BMA. Ces résultats laissent à penser que l'activité isométrique du quadriceps, le genou fléchi à 90°, peut être prescrite pour la réeducation, immédiatement après reconstruction du LCA. Ces données indiquent également que la mobilisation active (entre 50° et 110°) et la mobilisation passive peuvent être effectuées avec des risques mineurs après reconstruction. Les données concernant la mobilité passive peuvent aussi fournir des repères valables pour la reconstruction du LLA.

The measurement of anterior cruciate ligament stain in vivo

Maximum standardised uptake value of quantitative bone SPECT/CT in patients with medial compartment osteoarthritis of the knee

Despite the great amount of research that has been focused on the anterior cruciate ligament in recent years, relatively little is known about the exact mechanisms that cause these injuries. By defining the factors that contribute to these injury mechanisms in soccer players, the authors hope to facilitate appropriate training methods and work at preventing these serious injuries.

Mechanisms of injury of the anterior cruciate ligament in soccer players

Purpose
Bone single photon emission computed tomography (SPECT)/CT is considered as beneficial in unhappy patients with pain, stiffness or swelling after total knee arthroplasty (TKA). The purpose of this study was to identify typical patterns of bone tracer uptake (BTU), distribution and intensity values in patients after TKA. The above findings were correlated with the type and fixation of TKA, the time from TKA and intraoperative findings at revision surgery.

/pdf/clinical-value-of-spect-ct-in-the-painful-total-knee-3xlstfjcl3.pdf

Clinical value of SPECT/CT in the painful total knee arthroplasty (TKA): a prospective study in a consecutive series of 100 TKA.

Osteochondral lesions of the talus are often located posteromedially requiring open surgery to facilitate solid and complete osteochondral reconstruction. The aim of the study was to identify the optimal anatomical site for medial malleolar osteotomy based on the criteria of minimal cartilage damage (Study I) and to report on the morbidity in patients receiving osteotomy performed at the previously identified site (Study II). For Study I, cartilage coverage of the tibiofibular ankle joint facet was measured in 40 cadaveric ankles (20 cadaver specimens). In Study II, we assessed clinical (VAS pain score, AOFAS score, range of motion) and radiological outcome measures (SPECT-CT) in 17 patients (mean age, 36.8 ± 10.8 years) undergoing medial malleolar osteotomy. The medial edge in the transition zone of the tibial plafond to the medial malleolus showed less than 75 % of cartilage coverage in 62.5 % of cadavers (Study I). Surgery resulted in lower pain levels (2.4 ± 2.6 compared with 6.3 ± 1.8 points; p < 0.001) and greater AOFAS scores (82.9 ± 14.1 compared with 43.5 ± 10.8 to points; p < 0.001) compared with baseline (Study II). No signs of intra-operative damage or mal- or non-union were found. Long-term morbidity was found in one patient. Implant removal was necessary in 12 of 17 patients (71 %). Anatomically, there is an optimal location for the medial malleolar osteotomy at the medial ankle edge involving minimal cartilage damage. Clinical results using this location showed no short- or mid-term morbidity and little long-term morbidity. However, many patients required re-intervention for implant removal. IV.

Medial malleolar osteotomy for the treatment of talar osteochondral lesions: anatomical and morbidity considerations

The purpose was to prospectively evaluate the outcome, in particular the SPECT/CT bone tracer uptake (BTU) after high tibial osteotomy (HTO) due to symptomatic varus malalignment. It was the hypothesis that the BTU after HTO decreases in the medial compartment, clinical outcome and the degree of correction correlates with BTU and asymptomatic patients after HTO reveals a significantly decreased BTU in the medial subchondral areas. Twenty-two consecutive patients with 23 knees undergoing medial opening-wedge HTO for medial compartment overloading were assessed pre- and postoperatively (12 and/or 24 months) using Tc-99m-HDP-SPECT/CT including our 4D-SPECT/CT protocol. BTU was quantified and localized to specific biomechanically relevant joint areas. Maximum absolute and relative values (mean ± standard deviation, median and range) for each area were recorded. Pre- and postoperative mechanical alignment was measured. At 24 months after HTO, the WOMAC score was used. A significant decrease of BTU in the medial subchondral zones after HTO was found (preoperatively to 12 and 24 months postoperatively, p < 0.01). BTU normalized in all asymptomatic patients within 24 months. This decrease was partly seen in the lateral compartments, but significantly higher in the medial compartments (p < 0.0001). A significant increase of the BTU was noted in zones directly adjacent to the plate or within the osteotomy zone (p < 0.01). Decreased BTU was observed in osteotomy zones at 24 months postoperatively following higher uptake values at 12 months postoperatively. The average valgus correction of the tibiofemoral angle was 5.9° ± 2.8°. Less stiffness correlated significantly with a higher decrease in BTU (p < 0.05). Higher postoperative BTU significantly correlated with more pain (p < 0.05). No statistical significant associations between BTU and alignment correction were found. In patients with medial compartment, overloading due to varus malalignment HTO led to a significant decrease in BTU in the medial joint compartments. SPECT/CT BTU patterns and intensity in these patients pre- to 12 and 24 months postoperatively were seen. These correlated significantly with pain and stiffness. Hence, SPECT/CT could be used for assessment of adequate correction and healing after HTO. SPECT/CT could be further used to identify the optimal individualized correction for each patient and clinical scenario. Diagnostic prospective study, Level II.

/pdf/effect-of-high-tibial-osteotomy-on-joint-loading-in-1ihc1qggh8.pdf

Effect of high tibial osteotomy on joint loading in symptomatic patients with varus aligned knees: a study using SPECT/CT

Chondral lesions with osseous involvement represented by grades 3 and 4 showed higher SPECT/CT bone tracer uptake than those without osseous involvement (grades 1 and 2).

Do Chondral Lesions of the Knee Correlate with Bone Tracer Uptake by Using SPECT/CT?

Single photon emission computerized tomography and conventional computerized tomography (SPECT/CT) tracer uptake has been shown to reflect the loading history of the tibiofemoral knee joint and correlate with the mechanical and anatomical alignment. It was our primary purpose to develop a novel standardized SPECT/CT algorithm for patients undergoing high tibial osteotomy, evaluate the inter- and intra-observer reliability (OR), and assess the clinical applicability for follow-up of patients before and after high tibial osteotomy. The localization scheme defines 9 femoral, 8 patellar, and 13 tibial zones to accurately map the examined tracer uptake volume in each anatomical area of interest. Maximum values for each area (mean ± standard deviation, median, and range) of the localization scheme were recorded as well as normalized values for the intensity of SPECT/CT tracer uptake calculated. The inter- and intra-OR was assessed for SPECT/CT localization and tracer activity. Pre- and postoperative mechanical alignment was assessed in SPECT/CT using a custom-made specialized software. The median inter- and intra-observer differences of the measured mechanical alignment were calculated along with the inter- and intra-OR. The localization scheme showed near-perfect inter- and intra-OR (intra-class correlation coefficient (ICC) > 0.9) for the measurement of tracer activity and localization in all anatomical regions. For measurements of mechanical alignment, there was a strong agreement between the two observers (an inter-OR of ICC = 0.99 and an intra-OR of ICC = 0.98). The presented SPECT/CT algorithm is highly reliable and clinically feasible. Combined with mechanical alignment analysis, it provides the surgeon with helpful information about realignment effects of high tibial osteotomies (HTOs) and might help identify the optimal personalized degree of correction in HTO surgery.

/pdf/assessment-of-the-loading-history-of-patients-after-high-22ev9komnu.pdf

Assessment of the loading history of patients after high tibial osteotomy using SPECT/CT - a new diagnostic tool and algorithm

To assess the relationship of subchondral bone tracer uptake (BTU) on SPECT/CT and meniscal pathologies on MRI in patients with painful knees. Twenty-five patients who had MRI and SPECT/CT within 3 months without knee surgery or grade ≥3 cartilage lesions were prospectively included. Maximum values of each subchondral femorotibial area were quantified and a ratio was calculated in relation to a femoral shaft reference region, which represented the BTU background activity. Meniscal lesions were graded (intact/degeneration/tear) and meniscal extrusion (no/yes) was assessed using MRI by two musculoskeletal radiologists blinded to the SPECT/CT findings. One-tailed Spearman correlations served for statistics (p < 0.05). Knees with meniscal degeneration or tear showed a significantly higher BTU in the medial femorotibial compartment (p = 0.045) when compared to intact menisci. Meniscal degeneration was associated with an increased BTU in the lateral femorotibial compartment; however, this was not statistically significant (p = 0.143). Patients with an extruded meniscus showed significantly higher BTU compared to a non-extruded meniscus (p < 0.020). Medial femorotibial BTU in SPECT/CT was associated with meniscal pathologies. Highest BTU was found in patients with meniscal tears. SPECT/CT appears to be a useful imaging modality to identify patients with overloading or early osteoarthritis. •
 Meniscal degeneration and tears correlate significantly with increased BTU using SPECT/CT.
 •
 Medial meniscus extrusion is associated with an increased BTU in SPECT/CT.
 •
 SPECT/CT allows detection of overloading and early osteoarthritis.

Meniscal pathologies on MRI correlate with increased bone tracer uptake in SPECT/CT.

More than 200,000 new ACL injuries occur in the United States each year, from either direct or indirect forces on the knee, making it overall one of the most common knee injuries worldwide [1, 2]. More than three quarters of ACL injuries have been reported to occur in noncontact situations (no direct contact to the knee when knee is injured), mostly while performing sports. In team sports 50–80 % of ACL injuries occur in noncontact situations [3–6]. Noncontact injury means that there is no contact of the knee with any object in the moment of injury [1, 3, 7]. Typically, an ACL injury occurs when the foot strikes the ground with the knee close to full extension while landing manoeuvres, sudden deceleration or lateral cutting manoeuvres [8]. The likely loading conditions for a noncontact injury are an anterior tibial shear force, knee abduction and tibial internal rotation moments. In a cadaver study Levine et al. did not find a relationship between ACL disruption pattern (partial versus complete ACL tear, femoral insertion versus mid-substance versus tibial insertion) and different loading situations in simulated landings from a jump [9] (Fig. 7.1).

Milos Dordevic

Papers

Effect of high tibial osteotomy on joint loading in symptomatic patients with varus aligned knees: a study using SPECT/CT

Do Chondral Lesions of the Knee Correlate with Bone Tracer Uptake by Using SPECT/CT?

Assessment of the loading history of patients after high tibial osteotomy using SPECT/CT - a new diagnostic tool and algorithm

Meniscal pathologies on MRI correlate with increased bone tracer uptake in SPECT/CT.

Injury Mechanisms of ACL Tear