Collagen fibrous scaffolds for sustained delivery of growth factors for meniscal tissue engineering.

Aim: To mimic the ultrastructural morphology of the meniscus with nanofiber scaffolds coupled with controlled growth factor delivery to modulate cellular performance for tissue engineering of menisci. Methods: The authors functionalized collagen nanofibers by conjugating heparin to the following growth factors for sustained release: PDGF-BB, TGF-ß1 and CTGF. Results: Incorporating growth factors increased human meniscal and synovial cell viability, proliferation and infiltration in vitro, ex vivo and in vivo; upregulated key genes involved in meniscal extracellular matrix synthesis and enhanced generation of meniscus-like tissue. Conclusion: The authors' results indicate that functionalizing collagen nanofibers can create a cell-favorable micro- and nanoenvironment and can serve as a system for sustained release of bioactive factors.

Lay abstract Meniscal tears are a common injury to the part of the knee called the meniscus. Loss of meniscal tissue can lead to arthritis. In this study, the authors aimed to recreate the structure of the human meniscus using very thin (nanometers in diameter) fibers made of collagen. The authors also attached proteins called growth factors to the fibers. The addition of these proteins increased the growth rate of cells collected from human knee tissue. The levels of important genes involved in meniscal tissue formation were increased in these cells. These results show that adding proteins such as growth factors to collagen nanofibers can create an environment beneficial to growing meniscal tissue. Successful development of this technology could help in repairing meniscal damage in people.

Usefulness of three-dimensional computed tomography for patellofemoral measurement.

PURPOSE: This study aimed to establish the normal values for knee patellofemoral alignment as measured using 3-dimensional computed tomography (3D CT), to standardize the technique, and to show the inter- and intra-observer reliability of this measurement. METHODS: The present study included 62 asymptomatic volunteers (124 knees). 3D CT scanning was performed with each volunteer in the supine position with 15° of knee flexion, and consistent 3D axial images of the patellofemoral joint were obtained with alignment in the desired stereographic baseline direction in anterior-posterior, lateral, and axial rotations. Two independent observers measured patellofemoral alignment parameters, including the sulcus angle, congruence angle, lateral patellofemoral angle, condyle-patellar angle, and lateral trochlear inclination angle. RESULTS: Based on 3D CT measurement, the mean values of the parameters were 145.9° ± 9.2° for the sulcus angle, 12.6° ± 22.6° for the congruence angle, 9.2° ± 4.6° for the lateral patellofemoral angle, 14.1° ± 6.4° for the condyle-patellar (lateral facets) angle, - 8.5° ± 8.4° for condyle-patellar (patellar axis) angle, and 16.5° ± 6.3° for the lateral trochlear inclination angle. A statistically significant difference was observed between men and women in the sulcus and condyle-patellar (patellar axis) angles (p = 0.045, 0.011, respectively). All parameters showed excellent inter- and intra-observer reliability. CONCLUSION: The normal values and ranges for patellofemoral alignment parameters were evaluated using 3D CT. The results of this study provide reference information that may facilitate diagnosis and treatment planning of patellofemoral disorders in skeletally mature non-pathologic patients. LEVEL OF EVIDENCE: II.

Preoperative varus alignment and postoperative meniscus extrusion are the main long-term predictive factors of clinical failure of meniscal root repair.

PURPOSE: No studies have been conducted to determine long-term predictors of clinical failure after surgical root repair. This study identified long-term prognostic factors of clinical failure after pull-out repair of medial meniscus posterior root tears (MMPRTs) at a minimum of 10 year follow-up. METHODS: A total of 37 patients who underwent MMPRT pull-out repair and had been observed for more than 10 years were recruited for this study. The mean follow-up period was 125.9 ± 21.2 months. Clinical failure of the procedures was defined as conversion to total knee arthroplasty (TKA). Participants were categorized into two groups: non-failure and failure groups. Various factors, including demographic features and radiologic findings, were analyzed and compared between the two groups. Meniscus extrusion was assessed at coronal magnetic resonance imaging preoperatively and 1 year postoperatively. Independent risk factors were determined by univariate analysis and logistic regression analysis. To determine the cut-off value for risk factors, the receiver-operating characteristic curve analysis was performed. RESULTS: In total, eight patients (22%) were converted to TKA during the follow-up period. With univariate analysis, statistically significant differences between two groups were observed in mechanical varus alignment (P = 0.018), rate of the number of patient with more meniscal extrusion values after surgery (P = 0.024), and the difference between the preoperative and 1-year postoperative value of meniscus extrusion (mm) (P = 0.010). In a logistic analysis, OR of mechanical varus alignment and differences in meniscus extrusion value before and 1 year after surgery was 1.5 (P = 0.048) and 3.7 (P = 0.034). The cut-off values of mechanical varus alignment and differences in meniscus extrusion values were 5 degrees and 0.7 mm. CONCLUSION: Clinically, preoperative varus alignment and increased meniscal extrusion after surgery were found to be predictive for a clinical failure after meniscal root repair in a long-term perspective. Thus, these negative prognostic factors should be taken into consideration for performing root repair in MMPRTs. LEVEL OF EVIDENCE: Level III.

Results of total knee arthroplasty for painless, stiff knees.

BACKGROUND: Stiff knees, like completely ankylosed or arthrodesed knees, can be painless. Total knee arthroplasty (TKA) for these painless, stiff knees is technically demanding. However, it can correct the alignment and advance the range of motion to improve quality of life. So, we reviewed the preoperative and postoperative results of functional and pain scores, range of motion (ROM) and complications in painless, stiff knees treated by TKA. METHODS: Fifteen painless, stiff knees underwent TKA from January 1998 to January 2017. The mean follow-up period was 15.4 (2.4-22.2) years. All the knees were completely ankylosed or arthrodesed. Clinical outcome and complications were evaluated using medical record review, serial plan radiography, ROM assessment, Knee Society score (KSS), Knee Society function score (FS), and a visual analog scale for pain (VAS). RESULTS: All patients were satisfied with their operated knees. Mean KSS and FS scores were improved from 36 and 50.9 to 76.9 and 67.2, respectively (P < 0.001 and P = 0.01). The mean ROM increased from 0º preoperatively to 77.6º (15-130) at the final follow-up (P < 0.001). The mean VAS had worsened from 0 preoperatively to 0.2 postoperatively, however it was not significant (P = 0.1). Major postoperative complications were reported in five of the knees (33.3%). CONCLUSIONS: The results of TKA for painless, stiff knees were satisfactory with improved ROM and quality of life. Although some patients had mild pain and complications postoperatively, they were satisfied with the result. However, our study recommends that surgeons should consider the high rate of complications in the completely ankylosed or arthrodesed knees. LEVEL OF EVIDENCE: A retrospective case series, Level IV.

Root Repair Versus Partial Meniscectomy for Medial Meniscus Posterior Root Tears: Comparison of Long-term Survivorship and Clinical Outcomes at Minimum 10-Year Follow-up.

BACKGROUND: The importance of repair in medial meniscus posterior root tears (MMPRTs) has been increasingly recognized because it restores hoop tension. However, no study has compared the long-term outcomes between meniscectomy and repair. HYPOTHESIS: Survivorship and clinical outcomes of repair would be better than those of meniscectomy after long-term follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between 2005 and 2009, patients with MMPRTs who had been followed up for at least 10 years after partial meniscectomy (n = 18) or pullout repair (n = 37) were recruited. Clinical assessments, including the Lysholm score and International Knee Documentation Committee (IKDC) subjective score, were evaluated preoperatively and at the final follow-up. The final results in each group were compared with the preoperative results, and the final results of the groups were compared. Clinical failure was defined as conversion to total knee arthroplasty (TKA), and the final clinical scores were assessed just before TKA. Kaplan-Meier survival analysis was used to investigate the survival rates of surgical procedures. RESULTS: Mean ± SD follow-up period was 101.4 ± 45.9 and 125.9 ± 21.2 months in the meniscectomy and repair groups, respectively (P = .140). The mean Lysholm and IKDC scores, respectively, in the meniscectomy group were 50.8 ± 7.7 and 37.6 ± 7.0 preoperatively and 58.2 ± 22.1 and 44.4 ± 19.0 postoperatively (P = .124; P = .240). In the repair group, the mean Lysholm score and IKDC score, respectively, significantly increased from 52.3 ± 10.9 and 41.0 ± 9.6 preoperatively to 77.1 ± 24.0 and 63.7 ± 20.6 postoperatively (P < .001; P < .001). The final Lysholm and IKDC scores in the repair group were significantly better than those in the meniscectomy group (P = .004; P = .003). In cases of clinical failure, 10 patients (56%) in the meniscectomy group and 8 patients (22%) in the repair group converted to TKA in the follow-up period (P = .016). According to Kaplan-Meier analysis, the 10-year survival rates for the meniscectomy and repair groups were 44.4% and 79.6%, respectively (P = .004). CONCLUSION: In MMPRTs, root repair was superior to partial meniscectomy in terms of clinical results for at least 10 years of follow-up. From a long-term perspective, repair with restoration of hoop tension is more effective management than meniscectomy.

Comparative clinical outcomes of anterolateral ligament reconstruction versus lateral extra-articular tenodesis in combination with anterior cruciate ligament reconstruction: systematic review and meta-analysis.

BACKGROUND: Anterolateral augmentation procedures can be divided into traditional lateral extra-articular tenodesis (LET) and modern anterolateral ligament (ALL) reconstruction. Nevertheless, no studies have compared the clinical results between LET and ALL reconstruction, when combined with intra-articular ACL reconstruction. This study was therefore designed to compare the clinical results, including the anterior translation, rotational laxity, and patient-reported outcomes, in a group of patients who underwent ACL reconstruction combined with LET or ALL reconstruction. METHODS: All studies systematically searched until March 2018 without any language restriction that reported the results of a lateral extra-articular stabilization procedure using either LET or ALL reconstruction methods combined with ACL reconstruction were evaluated. Two reviewers independently recorded data from each study, including the sample size, improvement in Lysholm score, and the number of patients with each grade of knee laxity using Lachman and pivot shift tests. RESULTS: The pooled results of ten studies showed that the postoperative proportion of knees with grade 2 or 3 on the Lachman test was significantly higher following LET compared with ALL reconstruction in combination with ACL reconstruction (10.8%, 95% confidence interval [CI]: 6.6-17.1% vs. 1.5%, 95% CI 0.5-4.5%; p = 0.001). However, the pooled results of 12 studies showed that the proportion of knees that belonged to grade 2 or 3 on the pivot shift test, indicating poor rotational stability, was similar between these two techniques (4.9%, 95% CI 2.0-11.5% vs. 2.3%, 95% CI 1.1-4.5%; p = 0.101). The pooled improvements in Lysholm scores in these two groups were also similar (32.3, 95% CI 26.8-37.9 vs. 25.7, 95% CI 16.7-34.7, p = 0.218). CONCLUSION: LET could lead to worse anterior instability than with ALL reconstruction when these two approaches were combined with single-bundle ACL reconstruction. However, rotational stability and patient-reported outcomes were similar between the techniques.

National Trends of Meniscectomy and Meniscus Repair in Korea.

BACKGROUND: Meniscus surgeries are frequently performed in orthopaedics. However, their current status is not well known in many countries, including Korea. This study aimed to investigate the national trends of meniscus surgery in Korea. METHODS: Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service from 2010 to 2017. All cases coded as meniscectomy or meniscus repair were included. The total number and incidence of cases of meniscus surgery per 100,000 persons were determined, and the results were stratified by age and gender. The meniscus repair ratio for the total number of meniscus surgeries was evaluated. RESULTS: The total number and incidence of meniscectomy cases were 65,752 and 137, respectively, in 2010, which increased to 74,088 and 154, respectively, in 2017. The number of meniscectomies increased by 12.67% in 8 years. The total number and incidence of meniscus repair cases were 9,055 and 18, respectively, in 2010, which increased to 14,947 and 31 in 2017. The number of meniscus repairs increased by 65.04%. The meniscus repair ratio was 12.1% in 2010, which increased to 16.8% in 2017. The highest peak was noted for patients who underwent meniscus surgeries in their 50s and 60s. Meniscectomy was performed more frequently in women (57%) than in men (43%), whereas repair was performed more frequently in men (54%) than in women (46%) over the study period. CONCLUSION: The total number and incidence of meniscus surgeries increased from 2010 to 2017; the number and incidence of meniscus repair procedures increased more rapidly than those of meniscectomy, with the peak treatment age for both surgeries being in the 50s and 60s. The current study will contribute to understanding the epidemiology of meniscus surgery, its prevention, and cost-saving measures in Korea.

Pullout fixation for medial meniscus posterior root tears: clinical results were not age-dependent, but osteoarthritis progressed.

PURPOSE: This study investigated the outcomes of pullout fixation for medial meniscus posterior root tears (MMPRTs) in patients ≤ 60 years old versus patients > 60 years old. It was hypothesized that older patients would demonstrate results comparable with those of younger patients. METHODS: Patients with pullout fixation who were followed-up for more than 5 years were included. Patients were categorized into two groups based on age (group A, ≤ 60 years; group B, > 60 years). The Lysholm score, Kellgren-Lawrence (K-L, 0/1/2/3/4) grade, and medial joint space width were evaluated retrospectively. Preoperative results were compared with the final results in each group, which were compared between groups. RESULTS: Twenty-five patients in group A (mean age, 54.7 ± 3.8 years) and 22 patients in group B (mean age, 65.6 ± 4.4 years) were recruited. The mean follow-up duration was 70.9 months. The Lysholm score (group A, 53.0 ± 9.1 to 86.0 ± 12.1, P < 0.001; group B, 51.1 ± 7.1 to 82.9 ± 9.7, P < 0.001) improved significantly. However, the joint space width (group A, 4.7 ± 1.1 to 3.9 ± 1.1 mm, P < 0.001; group B, 4.7 ± 0.9 to 3.8 ± 0.9 mm, P < 0.001) and K-L grade (group A, 3/17/5/0/0 to 0/7/11/7/0, P < 0.001; group B, 2/14/6/0/0 to 0/3/14/5/0, P < 0.001) worsened significantly. No significant differences between groups were observed in final outcomes, including Lysholm score (n.s.), K-L grade (n.s.), and joint space narrowing (n.s.). No case with operation failure that require total knee arthroplasty was not observed. CONCLUSION: MMPRT fixation did not prevent the progression of arthrosis completely. However, clinical outcomes were not age-dependent. Thus, age may not be a critical factor to consider when applying fixation. LEVEL OF EVIDENCE: Retrospective case-control study; Level of evidence, IV.

Femoral tunnel widening is similar between anteromedial portal and transtibial techniques following single-bundle anterior cruciate ligament reconstruction: a systematic review and meta-analysis.

PURPOSE: In anterior cruciate ligament (ACL) reconstruction, there is concern regarding the potential risk of femoral tunnel widening in the anteromedial portal (AMP) technique due to the acute graft-bending angle at the aperture and the more elliptical aperture shape of the femoral tunnel compared to the transtibial (TT) techniques. Therefore, the aim of the current systematic review and meta-analysis was to compare the femoral tunnel widening between the AMP and TT techniques in patients who underwent ACL reconstruction. METHODS: It should be included the studies that reported on femoral tunnel widening in patients who underwent single-bundle ACL reconstruction, using soft-tissue tendon graft, with AMP and/or TT techniques. Two reviewers independently recorded data from each study, including the sample size and magnitude of tunnel widening after ACL reconstruction. RESULTS: Twenty-one studies were finally included in this meta-analysis. The pooled changes of absolute millimeters of tunnel widening from the immediate postoperative status to the last follow-up did not differ significantly between the AMP and TT techniques at both the aperture [3.31 mm, 95% confidence interval (CI) 1.7-5.0. mm versus 2.9 mm, 95% CI 2.4-3.4 mm, P = n.s.] and the midportion (3.5 mm, 95% CI 0.8-6.3 mm versus 3.0 mm, 95% CI 2.2-3.9 mm, P = n.s.) of the femoral tunnel. No significant difference was observed between the two techniques in the relative percentage of femoral tunnel widening (AMP; 28.8%, 95% CI 14.8-42.9% vs. TT; 29.7%, 95% CI 15.6-43.7%, P = n.s.). CONCLUSION: No significant difference in femoral tunnel widening was observed between the AMP and TT techniques, both in absolute millimeter and relative percentage, in patients who underwent single-bundle ACL reconstruction. This finding could alleviate the potential concerns associated with femoral tunnels being wider for the AMP than for the TT technique. LEVEL OF EVIDENCE: III.

Bipolar Injury of the Clavicle.

Eleven patients with bipolar clavicle injuries, including dislocation of both ends of the clavicle, dislocation of the sternoclavicular joint with distal clavicle fracture, dislocation of the acromioclavicular joint with medial clavicle fracture, and segmental fracture of the clavicle, were retrospectively reviewed. The purpose of this study was to report the clinical outcomes and a literature review of bipolar clavicle injury. Nonoperative treatment was performed for 5 patients and surgical treatment for 6 patients. The fracture or dislocation of the lateral end of the clavicle was fixed with a hook plate, and closed reduction of the medial end was performed; if the dislocation was still present, open reduction and anterior sternoclavicular ligament repair was performed. Visual analog scale pain score, Constant score, active range of motion, and radiological images were evaluated. The mean visual analog scale pain score for all patients was 0.7±0.9 (range, 0-2). The mean Constant score for all patients was 89.7±7.6 (range, 72-96). The mean Constant score was 84.2±8.5 (range, 72-96) for conservatively treated patients and 94.3±1.9 (range, 92-96) for surgically treated patients. The mean Constant score was 83.4±7.2 (range, 72-92) for patients in whom optimal reduction of 1 or both ends was not achieved. Residual pain or deformity was seen in 5 patients. The authors suggest operative treatment of bipolar clavicle injuries in younger, active patients when anatomical reduction cannot be achieved and residual deformity, pain, or functional limitations are unacceptable. [Orthopedics. 2018; 41(5):e681-e688.].

Corrigendum to: Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model.

[This corrects the article on p. 163 in vol. 22, PMID: 29520169.].

Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model.

PRF001 is a fragmented DNA polymer extracted from the testes of salmon. The purpose of this study was to assess the anti-inflammatory effect of PRF001 in vitro as well as the protective effect of PRF001 intake against arthritis in a rat model. In vitro, cell survival and inflammatory markers after H2O2 treatment to induce cell damage were investigated in CHON-001 cells treated with different concentrations of PRF001. In vivo, osteoarthritis was induced by intra-articular injection of monosodium iodoacetate (MIA) into the knee joints of rats. After consumption of PRF001 (10, 50, or 100 mg/kg) for 4 weeks, inflammatory mediators and cytokines in articular cartilage were investigated. In vitro, the levels of inflammatory markers, IL-1ß, TNF-α, COX-2, iNOS, and PGE2, were significantly suppressed by PRF001 treatment. In vivo, the inflammatory mediators and cytokines, IL-1ß, p-Erk1/2, NF-κB, TNF-α, COX-2, and PGE2, as well as MMP3 and MMP7, which have catabolic activity in chondrocytes, were decreased in the MIA-induced osteoarthritic rats following intake of PRF001. Histological analysis revealed that PRF001 had a protective effect on the articular cartilage. Altogether, these results demonstrated that the anti-inflammatory property of PRF001 contributes to its protective effects in osteoarthritis through deregulating IL-1ß, TNF-α, and subsequent signals, such as p-Erk1/2, NF-κB, COX-2, PGE2, and MMPs.

Survivorship Analysis and Clinical Outcomes of Transtibial Pullout Repair for Medial Meniscus Posterior Root Tears: A 5- to 10-Year Follow-up Study.

PURPOSE: This study investigated the clinical outcomes and mid- to long-term survival rates in patients undergoing transtibial pullout repair of medial meniscus posterior root tears (MMPRTs) after a minimum follow-up of 5 years. METHODS: Between 2005 and 2011, patients with MMPRTs who had been followed for at least 5 years after undergoing transtibial pullout repair were recruited. Participants were identified using medical records and information in a prospectively collected database. Clinical outcomes were assessed based on a comparison of patient preoperative Lysholm scores and their scores at the final follow-up. A Kaplan-Meier survival analysis was used to investigate the survival rates of repair procedures. Clinical failures were defined as cases requiring conversion to total knee arthroplasty (TKA) or having final Lysholm score <65 or less than their preoperative scores. RESULTS: Overall, 91 patients (mean age, 58.7 ± 9.7 years) were included: the mean follow-up duration was 84.8 ± 13.8 months. Among these patients, the mean Lysholm score improved significantly from 51.8 ± 7.9 preoperatively to 83.0 ± 11.1 at the final follow-up (P < .001). Overall, 4 patients failed due to conversion to TKA (n = 1) or having final Lysholm scores <65 or less than the preoperative scores (n = 3). The overall Kaplan-Meier probabilities of survival after repair were 99% at 5 years, 98% at 6 years, 95% at 7 years, and 92% at 8 years. CONCLUSIONS: Among patients with MMPRTs, transtibial pullout repair demonstrated a high clinical survival rate and the patients demonstrated clinical improvement, based on mid- and long-term follow-up examinations. LEVEL OF EVIDENCE: Level IV, retrospective uncontrolled case series.

Does synovialization after anterior cruciate ligament reconstruction have a positive effect on functional performance, outcomes scores, stability and muscle strength? A 2-year follow-up study after reconstruction.

BACKGROUND: To investigate the effect of synovialization of graft following anterior cruciate ligament reconstruction (ACLR) on functional performance test (FPT) and clinical outcomes. METHODS: Eighty-four male patients who underwent second-look arthroscopy at 2-year follow-up after unilateral ACLR using hamstring autograft were analyzed retrospectively. Patients were categorized by synovial coverage into A group (42 subjects, poor synovial coverage) and B group (42 subjects, good synovial coverage). FPT results, including those of single leg hop test (cm) of the involved limb, co-contraction test (s), shuttle run test (s), and carioca test (s), were compared between groups. Clinical scores, including Lysholm score, International Knee Documentation Committee (IKDC) subjective score, and Tegner activity score; stability assessments including Lachman test, Pivot-shift test, and side-to-side differences (cm) measured using a KT-2000 arthrometer were also compared between groups. RESULTS: Based on FPT results, no difference was evident between groups. Single leg hop test results were 144.3 ± 25.5 in A group and 145.4 ± 24.7 in B group (P = 0.849). Co-contraction test results were 17.1 ± 2.9 in A group and 16.9 ± 3.6 in B group (P = 0.827). Shuttle run test results were 9.3 ± 1.9 in A group and 9.3 ± 1.9 in B group (P = 0.935). Carioca test results were 11.4 ± 2.9 in A group and 10.5 ± 2.5 in B group (P = 0.149). Clinical scores and stability assessments did not differ between groups (P > 0.05). CONCLUSIONS: Based on functional performance results, well-synovialized grafts did not yield better functional performance outcomes following ACLR compared to poorly synovialized grafts at 2-year follow-up. The same was true of clinical outcomes. Thus, the success of synovialization does not improve functional performance and clinical outcomes following ACL reconstruction in an all-male population.

One stage revision single-bundle anterior cruciate ligament reconstruction with impacted morselized bone graft following a failed double-bundle reconstruction.

Although double-bundle anterior cruciate ligament (ACL) reconstruction has theoretical benefits such as more accurate reproduction of ACL anatomy, it is technically more demanding surgery. This report describes the case of a one stage revision single-bundle ACL reconstruction after primary double-bundle ACL reconstruction. A professional dancer had an ACL previously reconstructed with a double-bundle technique, but the femoral tunnels were malpositioned resulting in residual laxity and rotational instability. The previous femoral tunnel positions were vertical and widened. The previous vertical tunnels were filled with impacted bone graft and a revision single-bundle ACL reconstruction was performed via the new femoral tunnel with a 2 O'clock position between the previous two tunnels. After 10 months of postoperative rehabilitation, the patient returned to professional dancing with sound bony union and without any residual instability.

Erratum to: Betulin suppressed interleukin-1b-induced gene expression, secretion and proteolytic activity of matrix metalloproteinase in cultured articular chondrocytes and production of matrix metalloproteinase in the knee joint of rat.

[This corrects the article on p. 19 in vol. 21, PMID: 28066137.].

Betulin suppressed interleukin-1ß-induced gene expression, secretion and proteolytic activity of matrix metalloproteinase in cultured articular chondrocytes and production of matrix metalloproteinase in the knee joint of rat.

We investigated whether betulin affects the gene expression, secretion and proteolytic activity of matrix metalloproteinase-3 (MMP-3) in primary cultured rabbit articular chondrocytes, as well as in vivo production of MMP-3 in the rat knee joint to evaluate the potential chondroprotective effect of betulin. Rabbit articular chondrocytes were cultured and reverse transcription-polymerase chain reaction (RT-PCR) was used to measure interleukin-1ß (IL-1ß)-induced gene expression of MMP-3, MMP-1, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4), ADAMTS-5 and type II collagen. Effect of betulin on IL-1ß-induced secretion and proteolytic activity of MMP-3 was investigated using western blot analysis and casein zymography, respectively. Effect of betulin on MMP-3 protein production was also examined in vivo. The results were as follows: (1) betulin inhibited the gene expression of MMP-3, MMP-1, MMP-13, ADAMTS-4, and ADAMTS-5, but increased the gene expression of type II collagen; (2) betulin inhibited the secretion and proteolytic activity of MMP-3; (3) betulin suppressed the production of MMP-3 protein in vivo. These results suggest that betulin can regulate the gene expression, secretion, and proteolytic activity of MMP-3, by directly acting on articular chondrocytes.

Does Release of the Superficial Medial Collateral Ligament Result in Clinically Harmful Effects After the Fixation of Medial Meniscus Posterior Root Tears?

PURPOSE: To investigate pain and tenderness, stress testing, clinical outcome scores, complications, and operation time at 24 months and magnetic resonance imaging (MRI) analysis at 12 months after the release of the distal attachment of the superficial medial collateral ligament (sMCL) during medial meniscus posterior root tear (MMPRT) fixation. METHODS: Patients who received MMPRT fixation with a follow-up of at least 2 years were included. During fixation, the release of the distal attachment of the sMCL on the proximal tibia was performed to improve visualization and provide sufficient working space. Pain and tenderness at the released area, manual valgus stress tests of 30° and 0° flexion (grade 0/1/2/3), and subjective instability during weight bearing were evaluated serially at postoperative 3, 6, 12, and 24+ months. The contour of detachment area was assessed using MRI 12 months postoperatively. As a subgroup analysis, tourniquet time (minutes) and final clinical scores were compared between release and nonrelease groups. RESULTS: The numbers of participants in the release and nonrelease groups were 118 and 20 patients, and their mean follow-up durations were 42.4 ± 19.3 (24-95) and 37.2 ± 7.8 (30-55) months, respectively. In the release group, percentages of patients with pain and tenderness at 3 months were 15% and 18%, respectively; however, no patients had symptoms at 12 months. In valgus stress tests (30°, 0°), 12% and 2% of patients showed grade 1 laxity at 3 months, and 7% had grade 1 laxity in only 30° flexion at the final follow-up. However, no patients had subjective valgus laxity. An intact contour was confirmed in all cases among 94 patients checked by performing follow-up MRI. Tourniquet time was significantly shorter in the release group (42.4 ± 19.3) than in the nonrelease group (58.5 ± 9.5; P < .001). Between release and nonrelease groups, Lysholm (84.4 ± 12.1, 88.1 ± 12.8; P = .117) and International Knee Documentation Committee scores (73.6 ± 11.2, 77.5 ± 11.9; P = .112) did not differ. CONCLUSIONS: The release of the distal attachment of the sMCL during fixation of MMPRT did not result in pain and tenderness, residual instability, and complication. An intact contour of the sMCL was confirmed in all cases with MRI. This procedure reduced operation time and showed similar clinical results when compared between the release and nonrelease groups. However, this study had low power to detect the difference for clinical scores between the 2 groups. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Pullout Fixation of Posterior Medial Meniscus Root Tears: Correlation Between Meniscus Extrusion and Midterm Clinical Results

BACKGROUND: Medial meniscus posterior root tears (MMPRTs) lead to extrusion of the meniscus during weightbearing as well as loss of the ability of the meniscus to generate hoop stress. This loss of load-sharing ability leads to progressive arthritic changes. However, there have been no studies that correlate the correction of meniscus extrusion with clinical outcomes. HYPOTHESIS: Decreased meniscus extrusion is associated with better clinical and radiographic outcomes compared with increased meniscus extrusion after MMPRT pullout fixation. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 39 patients who underwent MMPRT pullout fixation and had been observed for more than 5 years were recruited for this study. The mean follow-up period was 69.8 months. Participants were categorized into 2 groups according to the direction of meniscus extrusion: group A (increased extrusion; 23 patients) and group B (decreased extrusion; 16 patients). Meniscus extrusion was assessed in the coronal plane on magnetic resonance imaging preoperatively and at 1 year postoperatively. The postoperative clinical outcomes (Lysholm and International Knee Documentation Committee [IKDC] scores) and radiographic results (Kellgren-Lawrence [K-L] grade and medial joint space) were compared between groups. RESULTS: Meniscus extrusion in group A increased significantly from a mean (±SD) of 3.5 ± 0.9 mm preoperatively to 5.1 ± 1.4 mm at 1 year postoperatively ( P < .001), whereas in group B, it decreased significantly from 4.1 ± 1.3 mm preoperatively to 3.5 ± 1.4 mm at 1 year postoperatively ( P < .001). The K-L arthritis grade (0/1/2/3/4) significantly progressed in group A (from 2/12/9/0/0 preoperatively to 0/1/14/8/0 postoperatively, respectively; P = .009) but not in group B (from 1/11/4/0/0 preoperatively to 0/6/8/2/0 postoperatively, respectively; P = .274). The mean final Lysholm and IKDC scores in group B (88.1 ± 12.1 and 79.0 ± 11.4, respectively) were significantly better than those in group A (81.0 ± 9.0 and 71.1 ± 7.8, respectively) ( P < .05). There was less medial joint space narrowing at final follow-up in group B (0.6 ± 0.8 mm) than in group A (1.1 ± 0.6 mm) ( P = .015). Progression of the K-L arthritis grade was seen in 50% (8/16) of the patients in group B compared with 87% (20/23) of the patients in group A ( P = .027). CONCLUSION: The current study demonstrates that in patients with MMPRTs, pullout fixation leads to favorable midterm outcomes, regardless of meniscus extrusion at 1-year follow-up. However, patients with decreased meniscus extrusion at postoperative 1 year have more favorable clinical scores and radiographic findings at midterm follow-up than those with increased extrusion at 1 year. This study indicates that one of the main goals of the repair of MMPRTs is to reduce meniscus extrusion as much as possible.