Nobuaki Miyaji

The diagnostic reliability of the quantitative pivot-shift evaluation using an electromagnetic measurement system for anterior cruciate ligament deficiency was superior to those of the accelerometer and iPad image analysis

PurposeSeveral non-invasive devices have been developed to obtain quantitative assessment of the pivot-shift test in clinical setting using similar but diverse measurement parameters. However, the clinical usability of those measurements has yet to be closely investigated and compared. The purpose of this study was to compare the diagnostic accuracy of three non-invasive measurement devices for the pivot-shift test.MethodsThirty patients with unilateral anterior cruciate ligament (ACL) injury were enrolled. The pivot-shift test was performed under general anaesthesia. Three devices, an accelerometer system (KiRA), an image analysis iPad application (iPad), and electromagnetic measurement system (EMS), were used simultaneously to provide two parameters, namely tibial acceleration monitored using KiRA and EMS, and tibial translation recorded using iPad and EMS. Side-to-side differences in each parameter and correlation between the measurements were tested, and a receiver-operating characteristic (ROC) curve analysis was conducted to compare their measurement accuracy.ResultsSignificant side-to-side differences were successfully detected using any of the measurements (all p < 0.01). KiRA demonstrated moderate correlation with the EMS for tibial acceleration (r = 0.54; p < 0.01), while poor correlation was observed between iPad and the EMS for the translation (r = 0.28; p < 0.01). The ROC curve analysis demonstrated better accuracy for the detection of ACL insufficiency in the EMS than KiRA and iPad for tibial acceleration and translation, respectively.ConclusionsAlthough all three measurements were similarly capable of detecting ACL deficiency, the EMS has the advantage of comprehensive evaluation of the pivot-shift test by evaluating both tibial acceleration and translation with higher accuracy than those of KiRA and iPad. It could be suggested that any of those measurement tools might improve the clinical diagnosis of ACL insufficiency.Level of evidenceDiagnostic study of consecutive patients with a universally applied gold standard, Level Ib.

Intraperitoneal injection of the SIRT1 activator SRT1720 attenuates the progression of experimental osteoarthritis in mice

Objectives This study aimed to examine the effects of SRT1720, a potent SIRT1 activator, on osteoarthritis (OA) progression using an experimental OA model. Methods Osteoarthritis was surgically induced by destabilization of the medial meniscus in eight-week-old C57BL/6 male mice. SRT1720 was administered intraperitoneally twice a week after surgery. Osteoarthritis progression was evaluated histologically using the Osteoarthritis Research Society International (OARSI) score at four, eight, 12 and 16 weeks. The expression of SIRT1, matrix metalloproteinase 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), cleaved caspase-3, PARP p85, and acetylated nuclear factor (NF)-κB p65 in cartilage was examined by immunohistochemistry. Synovitis was also evaluated histologically. Primary mouse epiphyseal chondrocytes were treated with SRT1720 in the presence or absence of interleukin 1 beta (IL-1β), and gene expression changes were examined by real-time polymerase chain reaction (PCR). Results The OARSI score was significantly lower in mice treated with SRT1720 than in control mice at eight and 12 weeks associated with the decreased size of osteophytes at four and eight weeks. The delayed OA progression in the mice treated with SRT1720 was also associated with increased SIRT1-positive chondrocytes and decreased MMP-13-, ADAMTS-5-, cleaved caspase-3-, PARP p85-, and acetylated NF-κB p65-positive chondrocytes and decreased synovitis at four and eight weeks. SRT1720 treatment partially rescued the decreases in collagen type II alpha 1 (COL2A1) and aggrecan caused by IL-1β, while also reducing the induction of MMP-13 by IL-1β in vitro. Conclusion The intraperitoneal injection of SRT1720 attenuated experimental OA progression in mice, indicating that SRT1720 could be a new therapeutic approach for OA. Cite this article: K. Nishida, T. Matsushita, K. Takayama, T. Tanaka, N. Miyaji, K. Ibaraki, D. Araki, N. Kanzaki, T. Matsumoto, R. Kuroda. Intraperitoneal injection of the SIRT1 activator SRT1720 attenuates the progression of experimental osteoarthritis in mice. Bone Joint Res 2018;7:252–262. DOI: 10.1302/2046-3758.73.BJR-2017-0227.R1.

Analysis of Graft Length Change Patterns in Medial Patellofemoral Ligament Reconstruction via a Fluoroscopic Guidance Method

Background: A fluoroscopic guidance method for medial patellofemoral ligament (MPFL) reconstruction has been widely used to determine the anatomic femoral attachment site. Purpose: To examine the graft length change patterns in MPFL reconstruction with a fluoroscopic guidance method. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Forty-four knees of 42 patients who underwent MPFL reconstruction for the treatment of recurrent patellar dislocation were examined prospectively. During surgery, suture anchors were inserted into the proximal one-third and center of the patella. A guide pin for the femoral tunnel was inserted into the position reported by Schöttle et al based on the true lateral view of the knee under fluoroscopic control. Changes in graft length patterns of the proximal and center anchors were examined through 0° to 120° of knee flexion. Favorable changes in length patterns were defined as meeting 2 of 3 criteria: (1) not long during flexion (≤3 mm between 30° and 120° of flexion) and either (2) nearly isometric during flexion between 0° and 90° or (3) slightly long during maximum extension (≤3 mm). Other patterns were considered unfavorable. If the change in length pattern was unfavorable, then the pin for the femoral tunnel was moved to different positions until it was favorable. Knees were separated into the favorable group and the unfavorable group. Differences between the groups regarding radiographic parameters were assessed. Student t test or chi-square test was used for statistical analysis. Results: Of the 44 knees, 31 (70.5%) showed favorable patterns. However, 13 knees (29.5%) showed unfavorable patterns; therefore, the position of the pin was changed. The mean ± SD distance from the original position to the final position was 5.3 ± 1.1 mm distal for 7 patients and 5.2 ± 0.4 mm posterodistal for 6 patients. Technical errors, including a nontrue lateral view and the tip of the wire not being in the determined area, were found for 4 of 13 knees in the unfavorable group. There was no statistical difference in radiographic parameters between the groups. Conclusion: The graft length change pattern could be nonphysiologic at the position determined through the fluoroscopic guidance method; thus, caution may be necessary. The change in length pattern should be checked before graft fixation. If the length change pattern is unfavorable, then it is advisable to move it approximately 5 to 7 mm distally or posterodistally from the first position.

Anterolateral Capsule Injury Did Not Aggravate Rotational Laxity of the Anterior Cruciate Ligament Injured Knees Measured by Quantitative Pivot-shift Evaluation

Objectives: The anterolateral capsule (ALC) injury concomitant with the anterior cruciate ligament (ACL) injured knees has been recently focused with potential effect on the knee rotational laxity. Although some basic in-vitro studies explored the effect of the additional ALC injury, most of such studies utilized their original rotational stress test rather than the clinically-used pivot-shift test. The knee rotational instability should be examined by the clinical pivot-shift test. Some quantitative measurement devices for the pivot-shift test have been clinically available lately. The purpose of this study were to evaluate the pivot-shift test using a quantitative measurement in clinical cases and to compare them between ACL injured knees with and without the ALC injury determined by magnetic resonance imaging (MRI). Methods: Eighty-five unilateral ACL injury patients (40 male and 45 female, age 25.3±11.7 y.o.) who were scheduled to have primary ACL reconstruction were included. Just prior to the ACL reconstruction, the pivot-shift test was performed under anesthesia while making the quantitative evaluation using electromagnetic measurement system (Fig.1). The tibial acceleration (m/sec2) during the pivot-shift was calculated, and the four levels of clinical grading was also determined according to the IKDC (none, glide, clunk, and gross). The concomitant ALC injury in the ACL injured knees was diagnosed on the MRI and divided into two groups ALC injured group (ALC+) and ALC intact group (ALC-). The differences of clinical grading and quantitative measurements were tested between ALC+ and ALC- groups. P-value of <0.05 was considered as statistically significant. Results: Forty-two patients had concomitant ALC injury. 21 knees of ALC+ group were graded as glide in clinical grading, 18 knees as clunk, and 3 knees as gross in ALC+ group, meanwhile 22 knees were assessed as glide, 17 knees as clunk, and 3 knees as gross in ALC- group. There was no difference in clinical grading between ALC+ and ALC- groups (p=0.97). The tibial acceleration measurement during the pivot-shift test demonstrated no significant difference between ALC+ group (1.4±1.2 m/sec2) and ALC- group (1.6±1.3 m/sec2) (p=0.21). Conclusion: This study demonstrated that the ALC injury accompanied with the ACL injury did not have significant effect on the rotational laxity based on either clinical grading or quantitative evaluation. There was a limitation of this study that statistical power was not so strong around 0.6, but, interestingly, the rotational laxity measurements was slightly larger in the ALC intact group. The ALC injury has been advocated as a major factor to aggravate the knee rotational laxity. In this study, however, the impact of the ALC injury on the rotational laxity was not confirmed. Therefore, we should pay more attention to other common and identifiable injures such as meniscus and cartilage tear.

Concomitant Lateral Meniscus Injury Aggravates Rotational Laxity of the Anterior Cruciate Ligament Injured Knees

Objectives: Residual rotational laxity in the anterior cruciate ligament (ACL) reconstructed knees is a remaining problem after the ACL reconstruction. Improper detection and treatment of the secondary restraint for the knee rotational laxity after the ACL were considered as the major reason for the problem. Although anterolateral ligamentous structure of the knee has increasingly been focused on, meniscus injury is frequently accompanied with the ACL injury and assumed to have significant impact on the rotational laxity based on previous studies. The purpose of this study was to determine the effect of the meniscus tear on the rotational laxity in the ACL-deficient knees. Methods: Fifty-seven unilateral ACL-injured patients (26 males and 31 females, 24 ± 10 y.o.) were tested. The protocol of this study was approved by the IRB in Kobe University, and the informed consent was obtained from all the patients. The pivot-shift test was performed under general anesthesia during their ACL reconstruction. (Fig.1) Clinical grading according to the IKDC (none, glide, clunk, and gross) was determined, whereas the quantitative assessment of the pivot-shift was conducted using electromagnetic measurement system to provide the tibial acceleration (m/sec2). Meniscus injuries were finally confirmed under arthroscopy during the ACL reconstruction. The difference of clinical grading and tibial acceleration between the ACL-injured knees with and without additional meniscus tear was assessed, followed by subgroup analysis for each medial and lateral meniscus tear separately. Statistical significance was set at p-value of 0.05. Results: Concomitant meniscus tear was confirmed in 32 knees. Clinical grading was different between the ACL-injured knees with and without meniscus tear (p<0.05), while the quantitative evaluation did not find a statistical significance (meniscus-injured knees 1.6 ± 1.1 m/sec2 vs meniscus-intact knees 1.3 ± 0.8 m/sec2, p=0.09). Subgroup analysis demonstrated increased tibial acceleration in the ACL-deficient knees with lateral meniscus tear (1.8 ± 1.1 m/sec2, n=19) compared to the meniscus-intact knees (p<0.05), whereas the rotational laxity did not rise in the medial meniscus torn knees (1.4 ± 1.0 m/sec2, n=20, p=0.33). Conclusion: Although the meniscus injury is the most common in addition to the ACL injury, the impact of the meniscus injury on the knee rotational laxity has not been fully examined. This study demonstrated the significant impact of the meniscus injury, especially lateral meniscus injury, on the rotational laxity in the ACL-deficient knees, which was successfully detected by using the quantitative measurement device. A careful inspection of the lateral meniscus tear should be required in the ACL-deficient knees with a substantial pivot-shift and, if there is any, it should be repaired as much as possible to avoid additional rotational laxity.