Tibial Tunnel Positioning Technique Using Bony/Anatomical Landmarks in Anatomical Anterior Cruciate Ligament Reconstruction

Because various biomechanical studies and clinical results have shown the effectiveness of an anatomical approach for anterior cruciate ligament (ACL) reconstruction, this approach has become gradually commonplace to improve postoperative performance. Standard tunnel positioning methods with accuracy, reproducibility, and adaptability to varied concepts are essential for the success of anatomical ACL reconstruction. However, there were no standard tibial tunnel positioning methods to satisfy these conditions. This technical note reports our tibial tunnel positioning technique using bony and/or anatomical landmarks for anatomical ACL reconstruction.

Remnant-Preserving Tibial Tunnel Positioning Using Anatomic Landmarks in Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To assess (1) if 6 anatomic landmarks (ALs) could be arthroscopically confirmed with remnant preservation and (2) if creating tibial tunnels using these landmarks reduces individual variation and improves reproducibility in double-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

We retrospectively reviewed data of patients who chronologically underwent double-bundle ACL reconstruction by either referencing the footprint after remnant dissection (non-AL group) or subsequently with the ALs (AL group). Using operative videos, 3 independent observers judged whether they could confirm 6 ALs (medial intercondylar ridge, medial and lateral intercondylar tubercles, anterior horn of lateral meniscus, Parsons' knob, and L-shaped ridge) in 20 patients randomly selected from the AL group. We then compared tunnel positions between the 2 groups, measured from the anterior and medial borders of the proximal tibia and expressed as percentage of the total depth and width of the proximal tibia using 3-dimensional computed tomography.

RESULTS

One hundred four patients (non-AL group, n = 54; AL group, n = 50) were included. All 6 ALs were arthroscopically confirmed in most cases (89.7% to 100%). The mean percentages of the anteroposterior (AP) depth for anteromedial (AM) tunnel, mediolateral (ML) width for AM tunnel, AP depth for posterolateral (PL) tunnel, and ML width for PL tunnel, respectively, were 27.8% ± 6.6%, 46.7% ± 2.8%, 41.4% ± 7.3%, and 46.1% ± 2.6% for the non-AL group and 30.7% ± 4.5%, 45.7% ± 2.2%, 45.2% ± 4.5%, and 46.9% ± 2.1% for the AL group, revealing significantly less variation in the AL group compared with the non-AL group, excluding the ML width of the PL tunnel (P = .007, .046, .002, .209, respectively).

CONCLUSIONS

Six landmarks could be reliably confirmed in cases with remnant preservation, and creating tibial tunnels using these landmarks were reproducible and resulted in less individual variation.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

What Components Comprise the Measurement of the Tibial Tuberosity-Trochlear Groove Distance in a Patellar Dislocation Population?

BACKGROUND

The tibial tuberosity-trochlear groove distance is used as an indicator for medial tibial tubercle transfer; however, to our knowledge, no studies have verified whether this distance is strongly affected by tubercle lateralization at the proximal part of the tibia. We hypothesized that the tibial tuberosity-trochlear groove distance is mainly affected by tibial tubercle lateralization at the proximal part of the tibia.

METHODS

Forty-four patients with a history of patellar dislocation and forty-four age and sex-matched controls were analyzed with use of computed tomography. The tibial tuberosity-trochlear groove distance, tibial tubercle lateralization, trochlear groove medialization, and knee rotation were measured and were compared between the patellar dislocation group and the control group. The association between the tibial tuberosity-trochlear groove distance and three other parameters was calculated with use of the Pearson correlation coefficient and partial correlation analysis.

RESULTS

There were significant differences in the tibial tuberosity-trochlear groove distance (p < 0.001) and knee rotation (p < 0.001), but there was no difference in the tibial tubercle lateralization (p = 0.13) and trochlear groove medialization (p = 0.08) between the patellar dislocation group and the control group. The tibial tuberosity-trochlear groove distance had no linear correlation with tubercle lateralization (r = 0.21) or groove medialization (r = -0.15); however, knee rotation had a good positive correlation in the patellar dislocation group (r = 0.62). After adjusting for the remaining parameters, knee rotation strongly correlated with the tibial tuberosity-trochlear groove distance (r = 0.69, p < 0.001), whereas tubercle lateralization showed moderate significant correlations in the patellar dislocation group (r = 0.42; p = 0.005).

CONCLUSIONS

Because the tibial tuberosity-trochlear groove distance is affected more by knee rotation than by tubercle malposition, its use as an indicator for tibial tubercle transfer may not be appropriate.

CLINICAL RELEVANCE

Surgical decisions of tibial tubercle transfer should be made after the careful analysis of several underlying factors of patellar dislocation.

Intrameniscal Gouty Tophi in the Knee: A Case Report

CASE

We report a case of recurrent acute arthritis and restricted range of motion in the knee joint, with magnetic resonance imaging subsequently detecting a nodular lesion within the lateral meniscus. Knee arthroscopy and histology revealed that the lesion was intrameniscal gouty tophi. After arthroscopic synovectomy and excision of the tophi, the symptoms resolved and the patient remained symptom-free at two years of follow-up.

CONCLUSION

Surgeons should be aware of the presence of such pathology and consider arthroscopic surgery if the mechanical symptoms persist.

Early Postoperative Intratunnel Migration of an EndoButton After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: A Case Report

CASE

We report a rare case of early postoperative migration of an EndoButton following anatomic double-bundle anterior cruciate ligament reconstruction with use of the EndoButton for femoral fixation. Although secure fixation of the EndoButton was confirmed during the operation, one-week postoperative radiographs revealed an intratunnel displacement of the posterolateral EndoButton. We performed a reoperation and refixed the EndoButton to the surface of the femoral cortex; we also hooked and tied both ends of the sutures to make a knot in order to prevent remigration.

CONCLUSION

Orthopaedic surgeons should be aware that EndoButton displacement and migration could arise at an early postoperative stage.

Bony Landmarks of the Anterior Cruciate Ligament Tibial Footprint: A Detailed Analysis Comparing 3-Dimensional Computed Tomography Images to Visual and Histological Evaluations

BACKGROUND

Although the importance of tibial tunnel position for achieving stability after anterior cruciate ligament (ACL) reconstruction was recently recognized, there are fewer detailed reports of the anatomy of the tibial topographic footprint compared with the femoral side.

HYPOTHESIS

The ACL tibial footprint has a relationship to bony prominences and surrounding bony landmarks.

STUDY DESIGN

Descriptive laboratory study.

METHODS

This study consisted of 2 anatomic procedures for the identification of bony prominences that correspond to the ACL tibial footprint and 3 surrounding landmarks: the anterior ridge, lateral groove, and intertubercular fossa. In the first procedure, after computed tomography (CT) was performed on 12 paired, embalmed cadaveric knees, 12 knees were visually observed, while their contralateral knees were histologically observed. Comparisons were made between macroscopic and microscopic findings and 3-dimensional (3D) CT images of these bony landmarks. In the second procedure, the shape of the bony prominence and incidence of their bony landmarks were evaluated from the preoperative CT data of 60 knee joints.

RESULTS

In the first procedure, we were able to confirm a bony prominence and all 3 surrounding landmarks by CT in all cases. Visual evaluation confirmed a small bony eminence at the anterior boundary of the ACL. The lateral groove was not confirmed macroscopically. The ACL was not attached to the lateral intercondylar tubercle, ACL tibial ridge, and intertubercular space at the posterior boundary. Histological evaluation confirmed that the anterior ridge and lateral groove were positioned at the anterior and lateral boundaries, respectively. There was no ligament tissue on the intercondylar space corresponding to the intercondylar fossa. In the second investigation, the bony prominence showed 2 morphological patterns: an oval type (58.3%) and a triangular type (41.6%). The 3 bony landmarks, including the anterior ridge, lateral groove, and intertubercular fossa, existed in 96.6%, 100.0%, and 96.6% of the cases, respectively.

CONCLUSION

There is a bony prominence corresponding to the ACL footprint and bony landmarks on the anterior, posterior, and lateral boundaries.

CLINICAL RELEVANCE

The study results may help create an accurate and reproducible tunnel, which is essential for successful ACL reconstruction surgery.

Phase II trial of cetuximab plus irinotecan for FOLFOX and FOLFIRI-refractory patients with EGFR-positive advanced and/or metastatic colorectal cancer: Evaluation of the efficacy and safety based on KRAS mutation status (T- CORE0801)

573

Background: Activating mutation of the KRAS gene is a predictive biomarker for loss of efficacy to anti-EGFR antibody therapy. However, this was mainly established by the evidences of Caucasian studies. Then, this prospective study investigated the role of KRAS mutations on efficacy and safety to cetuximab plus irinotecan in Japanese patients with metastatic colorectal cancer (mCRC).

Methods: We conducted a prospective study to analyze objective response to cetuximab plus irinotecan in molecularly defined KRAS wild-type (WT) or mutant subgroups of chemotherapy-refractory mCRC. KRAS mutations were detected by direct sequence on DNA from formalin-fixed, paraffin-embedded tissue of patients treated in 11 centers in Japan. Additional EGFR related genes such as BRAF, PIK3CA etc. and antibody-dependent cellular cytotoxicity related polymorphism in FCγRIIa and RIIIa genes were also examined.

Results: Forty-three patients were enrolled. KRAS mutations were found in 31.7% of 41 eligible patients. Response rate (RR) to cetuximab plus irinotecan, the primary endpoint of the study, was 17.9% and 0% for the patients with tumor harboring WT and mutant KRAS, respectively. No significant differences in toxicity were observed between the KRAS WT and mutant groups. Detail statistical analyses are ongoing.

Conclusions: We confirmed that KRAS status is a useful predictive maker for the efficacy to cetuximab plus irinotecan therapy in Japanese mCRC patients, even though the response rate in the KRAS WT group was lower than expected.

[Table: see text]

A randomized pilot study comparing safety and efficacy of irinotecan plus S-1 (IRIS) plus bevacizumab (BV) and modified (m) FOLFIRI plus BV in patients (pts) with metastatic colorectal cancer (mCRC): First report of T-CORE0702

496

Background: Sequential combination with irinotecan (CPT-11) and S-1 (IRIS) is active and safe regimen against mCRC (ASCO2008, abstract #4107, T. Yoshioka et al. Br J Cancer 101: 1972-77, 2009). The aim of this prospective randomized pilot study was to compare safety (CTCAE v3.0, primary endpoint) and efficacy (RR and PFS, secondary endpoint) of IRIS with mFOLFIRI when these were used with BV.

Methods: Sixty pts with mCRC were randomized to compare 30 pts for IRIS+BV (CPT-11 150 mg/m2 infusion on day 1, S-1 80 mg/m2 orally on day 3-16, q3w) with 30 pts for mFOLFIRI+BV (CPT-11 150mg/m2). 57 pts (IRIS arm 29, mFOLFIRI arm 28) were evaluable. Most of them were treated as first-line therapy.

Results: Background of pts was well balanced among two arms. Although G3/4 hematological AEs profiles were similar between two arms, G2-4 neutropenia was significantly lower in IRIS arm than mFOLFIRI arm (56.6%, vs. 88.9%, p=0.01, χ2test). Among G3/4 nonhematological AEs, gastrointestinal toxicities were lower in IRIS arm than mFOLFIRI arm (anorexia: 3.5% vs. 17.9%, nausea: 0% vs. 7.1%, diarrhea: 6.9% vs. 14.3%, stomatitis: 0% vs. 3.6%). By χ2 test, nausea, vomiting and hair loss were significantly lower in IRIS arm than mFOLFIRI arm (p<0.05). GI-perforation, a BV-related severe AE, occurred in 2 pts only from mFOLFIRI arm and one of them was died as TRD. RRs (institutional evaluation) were 58.6% in IRIS (CR 2, PR 15, SD 11, and PD 1) and 55.1% in mFOLFIRI arm (CR 0, PR 16, SD 10, PD 2, and not evaluable 1). Our independent review committee will clarified definite RR and median PFS near future.

Conclusions: Our IRIS+BV regimen is well tolerated, effective and appears to be a promising choice for pts with mCRC.

[Table: see text]

Phase I/II study of sequential therapy with irinotecan and S-1 for metastatic colorectal cancer

Background:

Both irinotecan (CPT-11) and S-1 are active against colorectal cancer; however, as S-1 is a prodrug of 5-fluorouracil (5-FU), 5-FU and its metabolites might inhibit the antitumour effect of CPT-11. Therefore, we designed a sequential combination, in which CPT-11 infusion was given on day 1 and S-1 was given orally at 80 mg m⁻² per day on days 3–16 every 3 weeks.

Methods:

Twelve patients entered the phase I study, and the recommended doses were determined as a CPT-11 dose of 150 mg m⁻² and an S-1 dose of 80 mg m⁻².

Results:

In all, 36 patients entered the phase II study, of whom 4 and 16 had complete and partial responses. The overall response rate was 55.6% (95% confidence interval, 38.1–72.1%), and median progression-free survival was 7.7 months (95% confidence interval, 4.8–12.6 months). Grade 3 neutropenia was the most common haematological toxicity and occurred in 6.5% of 215 treatment courses. Grade 3 non-haematological toxicities included anorexia (1.4%) and diarrhoea (0.9%). There was no grade 4 toxicity of any kind.

Conclusion:

Our results suggest that this regimen is convenient, safe and promising, compared with conventional regimens for patients with metastatic colorectal cancer.

CONSEL: for assessing the confidence of phylogenetic tree selection

CONSEL is a program to assess the confidence of the tree selection by giving the p-values for the trees. The main thrust of the program is to calculate the p-value of the Approximately Unbiased (AU) test using the multi-scale bootstrap technique. This p-value is less biased than the other conventional p-values such as the Bootstrap Probability (BP), the Kishino-Hasegawa (KH) test, the Shimodaira-Hasegawa (SH) test, and the Weighted Shimodaira-Hasegawa (WSH) test. CONSEL calculates all these p-values from the output of the phylogeny program packages such as Molphy, PAML, and PAUP*. Furthermore, CONSEL is applicable to a wide class of problems where the BPs are available.

AVAILABILITY

The programs are written in C language. The source code for Unix and the executable binary for DOS are found at http://www.ism.ac.jp/~shimo/

CONTACT

shimo@ism.ac.jp

Evaluating hypotheses on the origin and evolution of the New Zealand alpine cicadas (Maoricicada) using multiple-comparison tests of tree topology

The statistical testing of alternative phylogenetic trees is central to evaluating competing evolutionary hypotheses. Fleming proposed that the New Zealand cicada species Maoricicada iolanthe is the sister species to the major radiation of both low-altitude and montane Maoricicada species. However, using 1,520 bp of mitochondrial DNA sequence data from the cytochrome oxidase subunit I, tRNA aspartic acid, and the ATPase subunit 6 and 8 genes, we inferred that both M. iolanthe and another low-altitude species, Maoricicada campbelli, are nested within the montane Maoricicada radiation. Therefore, we examined the stability of the inferred phylogenetic placement of these two species using the newly developed Shimodaira-Hasegawa test (SH test) implemented in a maximum-likelihood framework. The SH test has two advantages over the more commonly used Kishino-Hasegawa (KH) and Templeton tests. First, the SH test simultaneously compares multiple topologies and corrects the corresponding P: values to accommodate the multiplicity of testing. Second, the SH test is correct when applied to a posteriori hypotheses, unlike the KH test, because it readjusts the expectation of the null hypothesis (that two trees are not different) accordingly. The comparison of P: values estimated under the assumptions of both the KH test and the SH test clearly demonstrate that the KH test has the potential to be misleading when the issue of comparing of a posteriori hypotheses is ignored and when multiple comparisons are not taken into account. The SH test, in combination with a variety of character-weighting schemes applied to our data, reveals a surprising amount of ambiguity in the phylogenetic placement of M. iolanthe and M. campbelli.

Consistency of SINE insertion topology and flanking sequence tree: quantifying relationships among cetartiodactyls

Short interspersed nuclear elements (SINEs) have been used to generate unambiguous phylogenetic topologies relating eukaryotic taxa. The irreversible nature of SINE retroposition is supported by a large body of comparative genome data and is a fundamental assumption inherent in the value of this qualitative method of inference. Here, we assess the key assumption of unidirectional SINE insertion by comparing the SINE insertion-derived topology and the phylogenetic tree based on seven independent loci of five taxa in the order Cetartiodactyla (Cetacea + Artiodactyla). The data sets and analyses were largely independent, but the loci were, by definition, linked, and thus their consistency supported an irreversible pattern of SINE retroposition. Moreover, our analyses of the flanking sequences provided estimates of divergence times among cetartiodactyl lineages unavailable from SINE insertion analysis alone. Unexpected rate heterogeneity among sites of SINE-flanking sequences and other noncoding DNA sequences were observed. Sequence simulations suggest that this rate heterogeneity may be an artifact resulting from the inaccuracies of the substitution model used.