The use of contralateral knee magnetic resonance imaging to predict meniscal size during meniscal allograft transplantation.

PURPOSE: The purpose of this study was to determine the size of each meniscus and compare it with the contralateral limb using conventional knee magnetic resonance imaging (MRI) taken from previously uninjured, healthy, young volunteers. METHODS: The knee joints of 60 healthy volunteers (aged 21 to 43 years, 30 men and 30 women) were enrolled in this study. Standard 3.0-T MRI in a controlled setting was used. By use of the mid-coronal images, the height and width of each medial and lateral meniscus were measured. By use of the mid-sagittal images, the height and width of the anterior and posterior horns of each meniscus was measured. The whole length spanning from the most anterior margin to the most posterior margin of each meniscus was also measured. Mean, standard deviation, and 95% confidence interval values were determined for each measurement. RESULTS: There were 3 incomplete discoid lateral menisci (10%) in men and 2 incomplete discoid menisci (6.7%) in women. The study group with non-discoid knees comprised 27 men and 28 women. The power of this study ranged from 0.57 to 0.66. All values showed good reliability (intraclass correlation coefficient range, 0.887 to 0.974). There were no significant differences between right and left menisci (all P > .05). There were significant differences between genders. All parameters showed significant differences (P < .05) except the medial meniscus width (P = .221). CONCLUSIONS: In this small subset of patients, there were no differences between right and left meniscal measurements according to MRI. Therefore, when one is performing meniscal allograft transplantation, contralateral knee MRI may be useful to determine the required size. Identifying both the overall width and length of each meniscus is important when preparing an allograft. CLINICAL RELEVANCE: Contralateral knee MRI may be used for more accurate meniscal size measurement in patients undergoing meniscal allograft transplantation.

Bilateral condyle fracture of tibial insert in mobile bearing total knee arthroplasty.

We report a case of polyethylene insert breakage in a 45-year-old man after 3.5 years of cruciate retaining type mobile bearing total knee arthroplasty (TKA). Interstingly, both condyles of the polyethylene insert have fractured. The visual assessment done by stereoscopic microscope in the investigation report suggested that the fracture propagation was a result of cyclic loading and that the fracture was from the articular surface as a result of tibio-femoral and anteroposterior shear loading. The initial flexion-extension gap mismatch and/or specific Asian habits like kneeling or deep knee bending could have been the possible factors for over-stress for the insert causing this complication. After replacement of the broken insert and modification for daily activity preventing deep knee flexion, the patient obtained complete relief of previous symptoms. It remains unclear whether insert breakage was secondary to polyethylene insufficient design or to the polyethylene material fracture propagation.

In vivo gap analysis in various knee flexion angles during navigation-assisted total knee arthroplasty.

Achieving rectangular flexion and extension gaps is important during gap balancing technique in total knee arthroplasty (TKA). However, assessment of gaps throughout the range of knee motion is obscure. One hundred knees operated by TKA using a navigation-assisted gap balancing technique were evaluated. Intraoperatively, after achieving rectangular flexion and extension gaps, mediolateral gaps in each flexion angle (0°, 45°, 90°, 120°) were recorded. Patients were divided into 4 groups; Group I: no gap difference (n = 64), Group II: lax in midflexion (n = 20), Group III: lax in deep flexion (n = 8) and Group IV: lax in both midflexion and deep flexion (n = 8). This study demonstrated that significant proportion (36%) of TKA cases had laxity in midflexion (45°) even when rectangular extension (0°)-flexion (90°) gap was achieved.

Second-look arthroscopic assessment of arthroscopic single-bundle posterior cruciate ligament reconstruction: comparison of mixed graft versus achilles tendon allograft.

BACKGROUND: Although controversy continues over the choice of graft tissue, including autografts, allografts, and synthetic ligaments, for posterior cruciate ligament (PCL) reconstruction, the use of a mixed graft consisting of a hamstring (semitendinosus and gracilis) autograft plus tibialis anterior allograft tendon has not been studied in detail. HYPOTHESIS: Outcomes of PCL reconstructions performed with a mixed graft would be superior to those using solely an Achilles tendon allograft in terms of functional knee scores, posterior stability, and the graft appearance. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Fifty-eight patients who underwent isolated single-bundle PCL reconstruction using an arthroscopic trans-septal portal with remnant preservation technique were evaluated. They were divided into group A (mixed tendon; n = 30) and group B (Achilles tendon; n = 28). Knee function was evaluated using the Lysholm knee score, Tegner activity score, and the International Knee Documentation Committee (IKDC) grading scale. Anteroposterior stability was measured using the Telos stress view. Twenty patients (66.7%) from group A and 21 patients (75.0%) from group B underwent hardware removal and a second-look arthroscopic examination. RESULTS: The Lysholm knee scores in groups A and B increased from a respective average of 43 and 50 preoperatively to 90 and 88 at follow-up. The IKDC grade and Tegner activity scores were also significantly improved in both groups. Stability was improved in both groups, with an average posterior laxity of 3.0 mm (group A) and 3.3 mm (group B) at follow-up (P > .05). However, there were 4 intraoperative complications in group B: 2 bone fractures and 2 graft pullouts during precyclic tensioning. Second-look arthroscopy revealed a partial tear in 8 cases (40%) from group A and 15 cases (71.4%) from group B (P = .03). All of the partial tears were located in the femoral aperture area. Complete synovial coverage was demonstrated in 10 patients (50%) from group A and 5 patients (23.8%) from group B (P = .04). However, clinical outcomes and stability were not affected by the arthroscopic graft appearance. CONCLUSION: Satisfactory results were obtained for groups A and B in patients who underwent reconstruction for isolated PCL injury. However, 4 intraoperative complications (14.3%) were encountered with use of the Achilles tendon allograft (group B), with a relative higher rate of partial tear and less synovialization in the femoral aperture area.

Tourniquet associated chemical burn.

Chemical burn under pneumatic tourniquet is an iatrogenic preventable injury and is rarely reported in the literature. The two important mechanisms are maceration (friction) and wetness underneath the tourniquent. In this report, our experience with two illustrative patients who presented with iatrogenic tourniquet associated burn is described.

The management of the popliteus hiatus during lateral meniscal transplantation.

Popliteofascicular injury had been proposed as a possible cause of unstable lateral meniscus. Meniscal repair at popliteal hiatus area during lateral meniscal allograft transplantation (MAT) had not been described in literature previously. In this report, a case of unstable lateral meniscus after MAT has been described. Arthroscopic repair for the unstable meniscus at popliteal hiatus resolved the mechanical symptom.