Arthroscopic Linear Chain Fixation for the Treatment of Medial Meniscus Posterior Root Tear: A Case Study.

BACKGROUND: The repair and reconstruction of medial meniscus posterior root tears (MMPRTs) is an important issue in the field of orthopedic sports medicine. This study reports the first application of arthroscopic linear chain fixation for the treatment of MMPRTs. CASE PRESENTATION: A 78-year-old female patient presented with a 1.5-month history of right knee pain accompanied by a locked facet joint. The patient underwent surgery with the new linear chain fixation method. In this method, the suture and the loop part of the buckle-strap titanium plate were combined into a linear chain mechanical complex, and the tension of the posterior root stump was gradually increased by pulling on the two attachment lines at the external mouth of the tibial tunnel. The postoperative Lysholm score was 89, and the visual analogue scale score was 0.9, indicating a significant improvement in knee joint function. At the 7-month and 1-year post-surgery follow-up, physical and MRI examinations confirmed satisfactory healing of the MMPRTs. CONCLUSION: This surgical approach offers several benefits, including a simplified instrumentation setup, preservation of natural anatomical structures, and reliable residual stump fixation. It has the potential for clinical implementation.

Prospective randomized comparison of knee stability and joint degeneration for double- and single-bundle ACL reconstruction.

PURPOSE: This study aims to determine the outcome of double-bundle anterior cruciate ligament (ACL) reconstruction using an allograft in comparison with ACL reconstruction using a double-bundle autograft or a single-bundle allograft. METHODS: A total of 424 patients who accepted primary ACL reconstructions were divided randomly into three groups: double-bundle technique with autograft (DB-AU group, n = 154), double-bundle technique with allograft (DB-AL group, n = 128), and single-bundle technique with allograft (SB group, n = 142). The KT-1000 arthrometer and pivot-shift tests were performed at 3, 12, and 36 months after surgery, and clinical outcome measurements include the Lysholm score and the IKDC rating scales. Radiological assessments evaluated arthritic changes and tunnel expansion at 36 months postoperatively. RESULTS: The KT-1000 test scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at 12 and 36 months postoperatively (P < 0.05). The pivot-shift tests scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at the 3, 12, and 36 month follow-ups (P < 0.05). Based on the IKDC score and Lysholm score, there were no significant difference between the three groups during follow-up (P > 0.05). At 36 months postoperatively, 42.3 % of patients in the SB group showed a progression in arthritic changes, which was greater than in the DB-AU (29.2 %) and DB-AL (27.3 %) groups (P < 0.05). At 36 months, the rates of tunnel expansion in the DB-AU group and the DB-AL group were lower than in the SB group (P < 0.05). CONCLUSIONS: Double-bundle ACL reconstruction can be used to achieve better anterior and rotational stability and has a lower rate of arthritic progression and tunnel expansion than the single-bundle procedure. LEVEL OF EVIDENCE: I.

Effects of myogenin on muscle fiber types and key metabolic enzymes in gene transfer mice and C2C12 myoblasts.

Skeletal muscle fiber type composition is one of the important factors influencing muscle growth and meat quality. As a member of the myogenic transcription factors, myogenin (MyoG) is required for embryonic myoblast differentiation, but the expression of MyoG continues in mature muscle tissue of adult animals, especially in oxidative metabolic muscle, which suggests that MyoG may play a more extended role. Therefore, using MyoG gene transfer mice and C2C12 myoblasts as in vivo and in vitro models, respectively, we elected to study the role of MyoG in muscle fiber types and oxidative metabolism by using overexpression and siRNA suppression strategies. The overexpression of MyoG by DNA electroporation in mouse gastrocnemius muscle had no significant effect on fiber type composition but upregulated the mRNA expression (P<0.01) and enzyme activity (P<0.05) of oxidative succinic dehydrogenase (SDH). In addition, downregulation of the activity of the glycolytic enzymes lactate dehydrogenase (LDH, P<0.05) and pyruvate kinase (PK, P<0.05) was observed in MyoG gene transfer mice. In vitro experiments verified the results obtained in mice. Stable MyoG-transfected differentiating C2C12 cells showed higher mRNA expression levels of myosin heavy chain (MyHC) isoform IIX (P<0.01) and SDH (P<0.05), while the LDH mRNA was attenuated. The enzyme activities of SDH (P<0.01) and LDH (P<0.05) were similarly altered at the mRNA level. When MyoG was knocked down in C2C12 cells, MyHC IIX expression (P<0.05) was decreased, but the mRNA level (P<0.05) and the enzyme activity (P<0.05) of SDH were increased. Downregulating MyoG also increased the activity of the glycolytic enzymes PK (P<0.05) and hexokinase (HK, P<0.05). Based on those results, we concluded that MyoG barely changes the MyHC isoforms, except MyHC IIX, in differentiating myoblasts but probably influences the shift from glycolytic metabolism towards oxidative metabolism both in vivo and in vitro. These results contribute to further understand the role of MyoG in skeletal muscle energy metabolism and also help to explore the key genes that regulate meat quality.

[Experimental research on repairing full-thickness articular cartilage defects by transplantation of autologous uncultured bone-marrow-derived mononuclear cells in combination with micro-fracture].

OBJECTIVE: To examine the feasibility of autologous uncultured bone-marrow-derived mononuclear cells (BM-MNCs) in combination with microfracture in a full-thickness articular cartilage defect model so as to provide experimental rationales for clinical applications. METHODS: A total of 40 rabbits were divided randomly into groups A, B, C and D (n = 10 each). In groups A and C, 5 ml marrow samples were harvested from left femur and then autologous BM-MNCs isolated. The full-thickness articular cartilage defects were made on femoral intercondylar fossa in right knees of rabbits. Group A: micro-fracture was made on cartilage defect and then autologous uncultured BM-MNCs-autologous fibrin gel complex implanted; Group B:the same micro-fracture was made on cartilage defect and autologous fibrin gel implanted; Group C:the cartilage defect was implanted with autologous uncultured BM-MNCs-autologous fibrin gel complex; Group D:the cartilage defect was implanted with autologous fibrin gel. Five rabbits were sacrificed at Weeks 8 and 12 post-transplantation in each group. And the reparative tissue samples evaluated grossly, histologically and immunohistochemically were graded according to the gross and histological scales. RESULTS: The statistical analyses of histological gradings at Weeks 8 and 12 showed that group A was significantly better than groups B, C and D (P < 0.05), groups B and C were better than group D (P < 0.05) and each group at Week 12 was better than itself at Week 6 (P < 0.05). CONCLUSION: Both of micro-fracture and transplantation of uncultured autologous BM-MNCs plus autologous fiber gel can promote the repair of cartilage defects. The combined use of micro-fracture and autologous uncultured BM-MNCs promotes the regeneration of articular cartilage so that it may provide theoretical rationales for clinical applications.

[Comparison of efficacies for two surgical methods in the treatment of medial tibial-femoral osteoarthritis].

OBJECTIVE: To compare the clinical efficacies of two surgical methods in the treatment of medial tibial-femoral osteoarthritis. METHODS: Between October 2007 and June 2010, a total of 22 cases (25 knees) with severe osteoarthritis in medial tibial-femoral compartment underwent minimally invasive unicompartmental knee arthroplasty (UKA) with Sled prosthesis after arthroscopic procedure. And its clinical efficacy was compared with that of 22 cases (25 knees) undergoing total knee arthroplasty (TKA) with Gemini MKII prosthesis almost simultaneously. RESULTS: There were no significant difference in general data between 2 groups (P > 0.05). Compared with the TKA group, the UKA group had a smaller blood loss ((148 ± 26) vs (278 ± 36) ml), a shorter operative duration ((68 ± 12) vs (86 ± 12) min), a faster progress of resuming 90° flexion ((3.18 ± 1.8) vs (9.1 ± 2.2) d) and an earlier off-bed time (P < 0.05). All patients were followed up for 6 - 34 months. There was no significant difference in KSS (Knee Society Score), function score or WOMAC (Western Ontario and McMaster Universities) score between 2 groups at the last follow-up (P > 0.05). CONCLUSION: The treatment of medial tibial-femoral osteoarthritis with minimally invasive UKA is superior to that with TKA in that it is less invasive, there is a faster recovery of joint functions and no significant difference exists in the mid-term clinical efficacies between them.

[Anterior cruciate ligament reconstruction using periosteum wrapped autologous hamstring tendons: clinical research].

OBJECTIVE: To develop a surgical technique using a periosteal flap wrapped autologous hamstring tendons in ACL reconstruction and to examine its short-term outcome. METHODS: A total of 110 patients (110 knees) were included. The experimental group (n = 52) received ACL reconstruction with hamstring tendons wrapped in periosteum. In the other 58 patients, ACL was reconstructed with autologous hamstring tendons. The mean post-operative follow-up was 19 (12 - 25) months. All patients were assessed at 12 months post-operation. The parameters of efficacy evaluation included IKDC score, Tegner score, modified HSS score, KT-1000 arthrometer reading and a radiographic assessment using anteroposterior and lateral radiographs. The incidence of femoral and tibial bone tunnel enlargement between two groups was compared with chi(2) test. RESULTS: Clinical outcomes in experimental group (periosteum-wrapped grafts) were dependent on the wrap-up of periosteum, bone tunnel, graft fixation and postoperative rehabilitation. The good or excellent outcomes were reported in approximately 90% of the experimental group. And 44 patients showed normal or nearly normal knee function according to IKDC criteria. KT-1000 tests showed an average maximal manual side-to-side difference of 1.7 +/- 1.1 mm. Forty patients showed the outcomes of KT-1000, Lachman's knee ligament test and pivot-shift testing. The evaluation of the level of activity using the Tegner score revealed that 40 patients regained their pre-injury activity level. And 44 patients showed full knee extension and 42 patients showed full knee flexion after surgery. The average HSS score showed no significant difference between experimental group (90.6 +/- 0.57 points) and control group (89.9 +/- 0.8 points) (t = 0.714, P > 0.05). The KT-1000 measurement (133N) was larger in control group (2.3 +/- 1.0 mm) than in experimental group (1.7 +/- 1.1 mm). There was significant difference in laxity between two groups (t = 6.427, P < 0.05). At 12 months post-operation, tunnel enlargement could be observed in both groups. The average enlargement of femoral tunnel was less in experimental group (17.3%) than control group (34.5%) (chi(2) = 4.17, P < 0.05). And the enlargement of tibial tunnel was less in experimental group (19.2%) than control group (36.2%) (chi(2) = 3.90, P < 0.05). CONCLUSIONS: The surgical technique using a periosteal flap wrapped with autologous hamstring tendons in ACL reconstruction has definite clinical efficacies. It can enhance the stability of knee and prevent the enlargement of bone tunnel.

[Effect of increased posterior tibial slope or partial posterior cruciate ligament release on knee kinematics of total knee arthroplasty].

OBJECTIVE: To compare the effects of increased posterior tibial slope or partial posterior cruciate ligament (PCL) release on knee kinematics of total knee arthroplasty (TKA). METHODS: Anteroposterior laxity, rotational laxity, varus and valgus laxity and maximum flexion angle were evaluated in 6 normal cadaver knees and the knees after TKA at flexion 0 degrees , 30 degrees , 60 degrees , 90 degrees and 120 degrees . Then the femoral prosthesis was shifted 5 mm posteriorly to simulate the tightly implanted knee. The same tests were performed on the tightly implanted knees. After that, the posterior tibial slope was increased 4 degrees or the PCL was partially released, and the same tests were made as in the normal knees respectively. Statistical analysis of the results was made using student's t test. RESULTS: Anteroposterior laxity, rotational laxity and varus and valgus laxity of the tightly implanted knees at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees were significantly less than those of the normal TKA knees (P < 0.05). Compared with the tightly implanted knees, anteroposterior laxity, rotational laxity and varus and valgus laxity at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees significantly improved after increased 4 degrees posterior tibial slope (P < 0.05); in the partial PCL released group, anteroposterior laxity at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees was significantly improved (P < 0.05), varus and valgus laxity was significantly improved only at flexion 90 degrees (P < 0.05), and rotational laxity was significantly improved at flexion 30 degrees , 60 degrees and 90 degrees (P < 0.05). Compared with PCL released group, varus and valgus laxity at flexion 30 degrees , 60 degrees and 90 degrees and rotational laxity at flexion 0 degrees , 30 degrees , 60 degrees and 90 degrees were significantly improved in the group of increased 4 degrees posterior tibial slope (P < 0.05). Maximum flexion angle of the tightly implanted knee (120.4 degrees ) was less than that of the normal TKA knees (130.3 degrees , P < 0.05) and that of increased 4 degrees posterior tibial slope group (131.1 degrees , P < 0.05). There was no significant difference at the maximum flexion angle between the increased 4 degrees posterior tibial slope group and the PCL released group (131.1 degrees vs 124.0 degrees , P = 0.0816). CONCLUSIONS: Anteroposterior laxity, varus and valgus laxity, rotational laxity and maximum flexion angle of the tightly implanted knees are less than those of the normal TKA knees. After increased 4 degrees posterior tibial slope, these indexes are improved significantly. Partial PCL released can significantly improve the anteroposterior laxity and had less effect on the varus and valgus laxity, rotational laxity and maximum flexion angle. So, a knee that is tight in flexion can be more likely to be corrected by increasing posterior tibial slope than by partially releasing PCL.

[The incidence and variation of tunnel enlargement after anterior cruciate ligament reconstruction].

OBJECTIVE: To investigate the incidence and variation of tunnel enlargement after anterior cruciate ligament (ACL) reconstruction. METHODS: ACL reconstructions using hamstring tendons were performed in 58 patients (58 knees) in the study. MRI scans were taken in a consistent manner at 1, 3, 6, 12 and 24 months after surgery to measure tibial and femoral tunnel expansion. RESULTS: Femoral tunnel enlargement was observed in 9 knees (9/58, 15.5%); Tibial tunnel enlargement was found in 12 knees (12/58, 20.7%). Of those with enlarged bone tunnels, there was no significant difference of tunnel diameters between 1 and 3 months after surgery (P>0.05). Six, 12 and 24 months postoperatively, the average tunnel diameters were larger than those of 1 or 3 months after surgery (P<0.05), however, no significant difference was found in between the tunnel diameters 6, 12 and 24 months postoperatively either (P>0.05). CONCLUSION: Tunnel expansion mainly occurs during 3 to 6 months after surgery, and it remains basically unchanged between 12 and 24 months postoperatively.