Search

Introduction: Little is known about peripheral rim instability (PRI) of adult discoid lateral meniscus (DLM). We compared PRI of the intact DLM (iDLM) to those of intact normal lateral meniscus (LM) in adult patients and also investigated whether there was any association between PRI and DLM tears.Materials and Methods: We investigated PRI in 17 DLMs and 60 normal LMs without tears during arthroscopic surgery for medial compartmental pathologies between June 2012 and October 2015. We also investigate PRI of torn DLM (tDLM) excluding peripheral tear to compare the PRI between intact and torn DLM. Stability parameters were measured using a probing hook and arthroscopic ruler at the anterior, middle, and posterior parts of the peripheral rim of the menisci: translating the anterior horn (AH) and mid-body (MB) and lifting the posterior horn (PH).Results: AH and PH instabilities were greater in the iDLM group than in the iLM group (2.2 ± 1.4 vs. 0.9 ± 1.4 mm, p = 0.006 and 3.4 ± 1.7 vs. 1.7 ± 1.2 mm, p = 0.004, respectively). However, there was no significant difference in MB instability between two groups. In addition, no significant difference was observed in all the parameters between the iDLM and tDLM groups.Conclusion: Both iDLM and tDLM had greater PRI of the AH and PH than the iLM in adult patients. Thus, the DLM is prone to tear and careful inspection is needed not to overlook PRI of a DLM even if the peripheral attachment is intact.Level Of Evidence: Level 3, comparative study of anatomical instability of living subjects. [ABSTRACT FROM AUTHOR]

Purpose: Pigmented villonodular synovitis (PVNS)/tenosynovial giant cell tumor (TGCT) is a benign, proliferative lesion of the synovium, the bursa, and the tendon sheath. Little is known about the anatomical distribution pattern of diffuse extra-articular PVNS/TGCT around the knee joint. In this retrospective study, anatomical distribution of PVNS/TGCT using magnetic resonance imaging (MRI) and arthroscopy was analyzed.Methods: This study was designed as a retrospective, observational cross-sectional study based on MRI and arthroscopy. Twenty-four PVNS/TGCT patients (24 knees) who underwent arthroscopic or posterior open surgery between 2009 and 2016 were enrolled. Of these, eight intra-articular and 16 diffuse extra-articular PVNS/TGCT of the knee were classified. The anatomical locations of the PVNS/TGCT masses were determined with a newly devised mapping scheme. Analysis was performed on the prevalence of each compartment and agreement rates between each compartment.Results: The point prevalence of intra-articular posterior compartment was higher in diffuse extra-articular PVNS/TGCT group compared with intra-articular PVNS/TGCT group. The point prevalence of diffuse PVNS/TGCT was most prevalent in the extra-articular posterolateral compartment (12 out of 16 diffuse extra-articular PVNS/TGCT patients, 75%) and second most common in the below to joint capsule compartment (11 out of 16, 68.8%). The agreement rate was the highest between intra-articular posterolateral and extra-articular posterolateral compartments (75%).Conclusion: Extra-articular invasion of diffuse PVNS/TGCT occurred in specific patterns in the knee joint. Extra-articular lesions were always accompanied by lesions in intra-articular compartments. In particular, lesions in the intra-articular posterior compartments were observed in all of the diffuse extra-articular PVNS/TGCT patients. The point prevalence of diffuse extra-articular PVNS/TGCT for each compartment was the highest [12 out of 16 (75%)] in extra-articular posterolateral compartment. In contrast, invasion to the extra-articular posteromedial side was less frequent [5 out of 16 (31.3%)] than to the extra-articular posterolateral side. Knowing where the lesions frequently occur may provide important information for deciding the timing, method, and extent of surgery.Level Of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: Previous work has shown the importance of restoring the normal structure of the native meniscus with meniscal allograft transplantation. Purpose/Hypothesis: The purpose of this study was to compare the anatomic positions of the anterior horn and posterior horn between the preoperative medial meniscus and the postoperative meniscal allograft after medial meniscal allograft transplantation with the bone-plug technique. The hypothesis was that the bone-plug technique could restore the preoperative structure of the native medial meniscus. Study Design: Case series; Level of evidence, 4. Methods: Between December 1999 and December 2013, a total of 59 patients (49 male, 10 female) underwent medial meniscal allograft transplantation by use of the bone-plug technique. The anatomic positions of both horns in the native medial meniscus and in the meniscal allograft were measured via MRI. The percentage reference method was used to measure the locations of both horns. Results: On coronal MRI, the mean absolute distance of the posterior horn from the lateral border of the tibial plateau changed from 45.2 ± 3.3 to 48.1 ± 4.2 mm (P < .05), and the percentage distance of the posterior horn changed from 59.6% to 63.0% (P < .05). On sagittal MRI, the mean absolute distance of the posterior horn from the anterior reference point changed from 40.3 ± 3.0 to 42.0 ± 3.5 mm (P < .05), and the mean percentage distance of the posterior horn changed from 76.5% to 79.4% (P <.05). On coronal MRI, the mean absolute distance of the anterior horn from the lateral border of the tibial plateau changed from 41.3 ± 4.2 to 48.5 ± 5.6 mm (P < .05), and the mean percentage distance of the anterior horn changed from 54.5% to 63.8% (P < .05). On sagittal MRI, the mean absolute distance of the anterior horn from the anterior reference point changed from 5.5 ± 1.0 to 9.9 ± 2.9 mm (P < .05), and the mean percentage distance of the anterior horn changed from 10.6% to 19.0% (P < .05). Conclusion: Despite attempts to place the meniscal allograft in the same position as the native meniscus, the anatomic locations of both horns were shifted posteromedially compared with those of the native medial meniscus. There were significant differences, attributed to several limitations in the bone-plug technique, between the preoperative and postoperative values of both horns. However, the posterior horn showed a location change of <5 mm, on average, in both the coronal and sagittal planes, whereas the anterior horn showed a location change of ≥5 mm in the coronal plane but <5 mm in the sagittal plane. [ABSTRACT FROM AUTHOR]