Characteristics of Nonunion After Arthroscopic Ankle Arthrodesis: A Multicenter Retrospective Cohort Study.

Nonunion is a major complication of arthroscopic ankle arthrodesis. However, the characteristics and risk factors of nonunion are not well understood. This retrospective multicenter observational study aimed to clarify the characteristics of nonunion after arthroscopic ankle arthrodesis. We included 154 patients who underwent arthroscopic ankle arthrodesis at any 1 of 5 institutions. Patients were divided into 2 groups: union and nonunion, and the groups were compared. Age, sex, body mass index, diabetes, smoking, corticosteroid use, diagnosis, treatment information, treatment protocol, radiographic evaluation, and patient-reported outcomes were recorded and analyzed. On radiographs, bony union was observed in 142 ankles (91.0%) but not in 12 ankles (9.0%). Postoperative radiographic tibial bony gap (mm) was significantly larger in the nonunion group (medial = 1.98, center = 1.65, anterior = 2.21, middle = 1.72, posterior = 3.01) than in the union group (medial = 1.35, center = 1.13, anterior = 1.28, middle = 1.03, posterior = 2.03). Furthermore, the visual analog score (VAS) of pain and pain-related self-administered foot evaluation questionnaire (SAFE-Q) subscale score significantly worsened in the nonunion group (VAS = 3.83, SAFE-Q subscale score = 69.8) compared to that in the union group (VAS = 1.35, SAFE-Q subscale score = 76.6). A larger radiographic tibiotalar bony gap was observed in the nonunion group. Other measurement outcomes were not associated with nonunion. Additionally, patient-reported outcomes markedly worsened in the nonunion group.

Larger sagittal inter-screw distance/tibial width ratio reduces delayed union or non-union after arthroscopic ankle arthrodesis.

BACKGROUND: Arthroscopic ankle arthrodesis (AAA) has risks of complications, such as delayed union and non-union. The number and direction of the inserted screws have been reported as important factors affecting the time to union of AAA. However, the ratio of inter-screw distance (ISD) to tibial width (TW) in different planes has not been investigated. Therefore, we aimed to explore the effect of this ratio on bone union following AAA. METHODS: We retrospectively enrolled 63 patients (64 ankles) undergoing AAA from 2013 to 2019. Then, their age, body mass index (BMI), sex, diabetes mellitus (DM) status, Takakura-Tanaka classification, number of screws and radiographic parameters were analysed. RESULTS: The patients had a mean age of 70.3 (range, 45-91) years. Bone fusion was achieved in 57 ankles (89%) in a mean period of 3.3 (range, 2-6) postoperative months. There were four cases of delayed union and three of non-union. No significant differences in age, BMI, sex, DM, Takakura-Tanaka classification, and number of screws could be detected between the groups. However, the sagittal ISD/TW ratio was significantly larger in the union group than in the delayed/non-union group with a cut-off value of 57.0%. CONCLUSION: Larger sagittal ISD/TW ratios result in reduced post-AAA delayed union or non-union. The surgeon should be aware that the anterior and posterior screw widths should be approximately 60% or more of the anteroposterior width of the tibia.

Comparison of screw versus locking plate fixation via sinus tarsi approach for displaced intra-articular calcaneal fractures.

BACKGROUND: The optimal treatment of displaced intra-articular calcaneal fractures (DIACF) is controversial. This study compared the fixation stability of screws and locking plates in DIACF treated via the sinus tarsi approach (STA). METHODS: We retrospectively evaluated 118 DIACF cases treated via STA and extracted data that could affect treatment outcomes. Loss of Böhler's angle after surgery was measured to compare fixation stability. RESULTS: The loss of Böhler's angles was significantly smaller in the locking plate group than in the screw group (2.6 ± 2.7º vs. 5.6 ± 5.3º, P < 0.01). There was no difference in the clinical outcomes between the groups. On multivariate logistic regression analysis, screw fixation was significantly associated with loss of Böhler's angle by> 10º (odds ratio, 8.63; 95% confidence interval, 1.16-64.4; P < 0.05). CONCLUSIONS: Locking plate fixation is more reliable than screw fixation for preventing correction loss in DIACF treated via STA. LEVEL OF EVIDENCE: III.

Elevated Expression of CCN3 in Articular Cartilage Induces Osteoarthritis in Hip Joints Irrespective of Age and Weight Bearing.

Osteoarthritis (OA) occurs not only in the knee but also in peripheral joints throughout the whole body. Previously, we have shown that the expression of cellular communication network factor 3 (CCN3), a matricellular protein, increases with age in knee articular cartilage, and the misexpression of CCN3 in cartilage induces senescence-associated secretory phenotype (SASP) factors, indicating that CCN3 promotes cartilage senescence. Here, we investigated the correlation between CCN3 expression and OA degenerative changes, principally in human femoral head cartilage. Human femoral heads obtained from patients who received total hip arthroplasty were categorized into OA and femoral neck fracture (normal) groups without significant age differences. Gene expression analysis of RNA obtained from femoral head cartilage revealed that CCN3 and MMP-13 expression in the non-weight-bearing part was significantly higher in the OA group than in the normal group, whereas the weight-bearing OA parts and normal cartilage showed no significant differences in the expression of these genes. The expression of COL10A1, however, was significantly higher in weight-bearing OA parts compared with normal weight-bearing parts, and was also higher in weight-bearing parts compared with non-weight-bearing parts in the OA group. In contrast, OA primary chondrocytes from weight-bearing parts showed higher expression of CCN3, p16, ADAMTS4, and IL-1ß than chondrocytes from the corresponding normal group, and higher ADAMTS4 and IL-1ß in the non-weight-bearing part compared with the corresponding normal group. Acan expression was significantly lower in the non-weight-bearing group in OA primary chondrocytes than in the corresponding normal chondrocytes. The expression level of CCN3 did not show significant differences between the weight-bearing part and non-weight-bearing part in both OA and normal primary chondrocytes. Immunohistochemical analysis showed accumulated CCN3 and aggrecan neoepitope staining in both the weight-bearing part and non-weight-bearing part in the OA group compared with the normal group. The CCN3 expression level in cartilage had a positive correlation with the Mankin score. X-ray analysis of cartilage-specific CCN3 overexpression mice (Tg) revealed deformation of the femoral and humeral head in the early stage, and immunohistochemical analysis showed accumulated aggrecan neoepitope staining as well as CCN3 staining and the roughening of the joint surface in Tg femoral and humeral heads. Primary chondrocytes from the Tg femoral head showed enhanced expression of Ccn3, Adamts5, p16, Il-6, and Tnfα, and decreased expression of Col2a1 and -an. These findings indicate a correlation between OA degenerative changes and the expression of CCN3, irrespective of age and mechanical loading. Furthermore, the Mankin score indicates that the expression level of Ccn3 correlates with the progression of OA.

Outcome after resection arthroplasty or shortening oblique osteotomy of the lesser metatarsals combined with arthrodesis of the first metatarsophalangeal joint for severe rheumatoid forefoot deformities.

PURPOSE: We investigated objective and patient-reported outcomes after resection arthroplasty or shortening oblique osteotomy (SOO) of the lesser metatarsals combined with arthrodesis of the first metatarsophalangeal (MTP) joint for severe rheumatoid forefoot deformities. METHODS: 17 feet from 14 women (mean age, 67.8 years) underwent resection arthroplasty of the lesser metatarsal heads (MTH resection group), while 13 feet from nine women and two men (mean age, 68.7 years) underwent SOO of the lesser metatarsals (MTH preservation group). Arthrodesis of the first MTP joint was performed in all cases. Mean follow-up in the MTH resection and preservation groups was 25.0 and 21.3 months, respectively. Preoperative and postoperative clinical evaluation included Japanese Society for Surgery of the Foot (JSSF) scale and self-administered foot evaluation questionnaire (SAFE-Q) scores. RESULTS: Mean total JSSF scale significantly improved from 53.4 to 76.4 in the MTH resection group (p < .001) and from 50.1 to 74.2 in the MTH preservation group (p = .002). Pain and pain-related and shoe-related SAFE-Q subscale scores significantly improved after surgery in both groups. In the MTH resection group, recurrence of painful callosities and claw toe deformity was observed in four and three feet, respectively. In the MTH preservation group, one patient experienced recurrence of painful callosities and one underwent revision surgery for IP joint dislocation. CONCLUSION: Resection arthroplasty or SOO of the lesser metatarsals combined with arthrodesis of the first MTP joint achieved significant improvement with respect to pain relief, deformity correction, and footwear comfort.

Subjective and Objective Outcomes of Surgery for Rheumatoid Forefoot Deformities Under the Current Treatment Paradigm.

We investigated the clinical outcomes of surgical procedures for the treatment of forefoot deformities in patients with rheumatoid arthritis. Twenty feet in 16 women (mean age 62.1 years) underwent corrective osteotomy of the first metatarsal bone with shortening oblique osteotomy of the lesser metatarsophalangeal joints (joint-preservation group), while 13 feet in 12 women (mean age 67.4 years) underwent arthrodesis of the first metatarsophalangeal joint with resection arthroplasty of the lesser metatarsophalangeal joints (joint-sacrifice group); mean follow-up for each group was 25.8 and 23.8 months, respectively. The mean total Japanese Society for Surgery of the Foot (JSSF) scale improved significantly from 64.2 to 89.2 in the joint-preservation group (p < .001), and from 54.2 to 74.2 in the joint-sacrifice group (p = .003). In the joint-preservation group, the postoperative range of motion (ROM) of the joint, walking ability, and activities of daily living scores of the JSSF scale were significantly higher than those in the joint-sacrifice group (p = .001, p = .001, and p = .019, respectively). There were no differences in the subscale scores of the self-administered foot evaluation questionnaire between 2 groups either pre- or postoperatively. No differences in the postoperative complications were found between 2 groups. Although the joint-sacrificing procedure resulted in lower objective outcomes than the joint-preserving procedure regarding the ROM of the joint, the walking ability, and the level of activities of daily living, both procedures resulted in similar treatment outcomes when evaluated by the subjective measures.

A Novel Radiographic Measurement Method for the Evaluation of Metatarsophalangeal Joint Dislocation of the Lesser Toe in Patients with Rheumatoid Arthritis.

Dorsal dislocation of metatarsophalangeal (MTP) joints of the lesser toe frequently occurs in patients with rheumatoid arthritis (RA), and may cause painful and uncomfortable plantar callosities and ulceration. The current study examined the reliability and clinical relevance of a novel radiographic parameter (the MTP overlap distance [MOD]) in evaluating the severity of MTP joint dislocation. The subjects of the current study were 147 RA patients (276 feet; 1104 toes). MOD, defined as the overlap distance of the metatarsal head and the proximal end of the phalanx, was measured on plain radiographs. The relationship between the MOD and clinical complaints (forefoot pain and/or callosity formation) was analyzed to create a severity grading system. As a result, toes with callosities had a significantly larger MOD. ROC analysis revealed that the MOD had a high AUC for predicting an asymptomatic foot (-0.70) and callosities (0.89). MOD grades were defined as follows: grade 1, 0 ≤ MOD < 5 mm; grade 2, 5 ≤ MOD < 10 mm; and grade 3, MOD ≥ 10 mm. The intra- and inter-observer reliability of the MOD grade had high reproducibility. Furthermore, the MOD and MOD grade improved significantly after joint-preserving surgeries for lesser toe deformities. Our results suggest that MOD and MOD grade might be useful tools for the evaluation of deformities of the lesser toe and the effect of surgical intervention for MTP joints in patients with RA.

Steep posterior slope and shallow concave shape of the medial tibial plateau are risk factors for medial meniscus posterior root tears.

PURPOSE: Bone morphological factors are important for menisci. Their association with medial meniscus posterior root tears, however, has not yet been studied. This study aimed to compare sagittal medial tibial slope and medial tibial plateau depth between knees with and without medial meniscus posterior root tears. METHODS: Nine healthy volunteers, 24 patients who underwent anterior cruciate ligament reconstruction, and 36 patients who underwent medial meniscus posterior root pullout repair were included. Magnetic resonance imaging examinations were performed in the 10°-knee-flexed position. The medial tibial slope and medial tibial plateau depth were compared among the groups. RESULTS: In healthy volunteers, the anterior cruciate ligament reconstruction group, and the medial meniscus posterior root tear group, the medial tibial slopes were 3.5° ± 1.4°, 4.0° ± 1.9°, and 7.2° ± 1.9°, respectively, and the medial tibial plateau depths were 2.1 ± 0.7 mm, 2.2 ± 0.6 mm, and 1.2 ± 0.5 mm, respectively. Patients with medial meniscus posterior root tears had a significantly steep medial tibial slope and shallow medial tibial plateau concavity compared to those of healthy volunteers (P < 0.01) and the anterior cruciate ligament group (P < 0.01). In the multivariate logistic regression analysis, body mass index, medial tibial slope, and medial tibial plateau depth were significantly associated with medial meniscus posterior root tears. CONCLUSIONS: A steep posterior slope and a shallow concave shape of the medial tibial plateau are risk factors for medial meniscus posterior root tear. LEVEL OF EVIDENCE: Level III: Case-control study.

Effect of Lateral Gutter Osteophyte Resection on Correction of Varus Deformity in Arthroscopic Ankle Arthrodesis.

BACKGROUND: Recently, arthroscopic ankle arthrodesis has been performed for moderate-to-severe varus-deformed ankle osteoarthritis. However, the effect of osteophyte resection in the lateral gutter in arthroscopic ankle arthrodesis has not been clarified. We hypothesized that a varus-deviated ankle with lateral gutter osteophytes can be corrected by osteophyte resection. METHODS: Thirty-nine ankles of 38 patients were included. The mean age of patients was 70.0 (45-83) years. The patients were divided into the following groups: group with an osteophyte in the lateral gutter (osteophyte) and group with no osteophytes (nonosteophyte). Preoperative and postoperative tibiotalar angle, tibial plafond angle, and tibiotalar angle under valgus stress, as well as the Japanese Society for Surgery of the Foot (JSSF) ankle/hindfoot scale, were recorded. Twelve ankles underwent lateral gutter osteophyte resection, whereas the other 27 ankles did not require osteophyte resection. RESULTS: Preoperative tibiotalar angle was higher in the osteophyte group than in the nonosteophyte group (21.8 vs 11.2 degrees, P = .01). The tibiotalar angle in the preoperative valgus stress imaging was higher in the osteophyte group (12.9 vs 5.7, P < .01). However, the postoperative tibiotalar angle was similar between the 2 groups (7.1 vs 5.4, P = .183). JSSF ankle/hindfoot scale improved in both groups. CONCLUSION: Lateral gutter osteophyte resection enabled correction of the varus malalignment in arthroscopic ankle arthrodesis. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Clinical outcomes of treatment with locking compression plates for distal femoral fractures in a retrospective cohort.

BACKGROUND: Plate fixation is one of the standard surgical treatments for distal femoral fractures. There are few reports on the relationship between the screw position and bone union when fixing by the bridging plate (relative stability) method. METHODS: This retrospective study included 71 distal femoral fractures of 70 patients who were treated with the locking compression plate for distal femur (DePuy Synthes Co., Ltd, New Brunswick, CA, USA). The following measurements were evaluated and analyzed: (1) bone union rate, (2) bridge span length (distance between screws across the fracture), (3) plate span ratio (plate length/bone fracture length), (4) number of empty holes (number of screw holes not inserted around the fracture), and (5) medial fracture distance (bone fracture distance on the medial side of the distal femur). Patient demographics (age), comorbidities (smoking, diabetes, chronic steroid use, dialysis), and injury characteristics (AO type, open fracture, infection) were obtained for all participants. Univariate analysis was performed on them. RESULTS: Of 71 fractures, 26 fractures were simple fractures, 45 fractures were comminuted fractures, and 7 fractures resulted in non-union. Non-union rate was significantly higher in comminuted fractures with bone medial fracture distance exceeding 5 mm. Non-union was founded in simple fractures with bone medial fracture distance exceeding 2 mm, but not significant (p = 0.06). In cases with simple fractures, one non-union case had one empty hole and one non-union case had four empty holes, whereas in cases with comminuted fractures, five non-union cases had two more empty holes. CONCLUSIONS: We concluded that bone fragment distance between fracture fragments is more important than bridge span length of the fracture site and the number of empty holes. Smoking and medial fracture distance are prognostic risk factors of nonunion in distal femoral fractures treated with LCP as bridging plate.

Time-Dependent Increase in Medial Meniscus Extrusion after Medial Meniscus Posterior Root Tear Analyzed by Using Magnetic Resonance Imaging.

PURPOSE: Medial meniscus posterior root tear (MMPRT) causes progression of medial meniscus extrusion (MME). This study aims to calculate the progression rate of MME based on findings in two preoperative magnetic resonance imaging (MRI) scans and determine the associated factors. MATERIALS AND METHODS: We retrospectively reviewed 33 patients (27 females and 6 males; mean age, 60 years) who underwent MRI twice, at a mean interval of 48 days. We measured the medial meniscus body width, medial joint space width (MJSW), and MME. The MME progression rate was derived from regression analysis of the increase in MME (ΔMME) between the two MRI scans. In addition, the correlations of the MME increase rate with age, body mass index, femorotibial angle, and MJSW were evaluated. RESULTS: The mean MME increased from 3.4 mm to 4.5 mm (p<0.001). A good correlation was observed between ΔMME and the interval of MRI scans (R2=0.621), and the MME progression rate was 0.020 mm per day. A moderate correlation was observed between the MME increase rate and the MJSW (R2=0.432). CONCLUSIONS: The MME progression rate was rapid in MMPRT and narrowing of the MJSW was associated with the progression of MME. LEVEL OF EVIDENCE: V, Cross-sectional study.

Nonunion fragility fracture of the pelvis with complication from bladder rupture: A case report.

The incidence rate of bladder rupture associated with pelvic ring fractures is reported to be about 5-10%, mostly occurring at the time of injury. Fragility pelvic ring fractures are reported to increase fracture displacement or become nonunion if they are treated inadequately. Few case reports on bladder rupture associated with fragility pelvic ring fracture have been published. We report a rare case of delayed bladder rupture associated with a fragility fracture of the pelvis. A 65-year-old female felt right hip pain without sustaining any trauma. She was diagnosed with a right pubic rami fracture. However, her pain deteriorated, and a sacral fracture was identified one month later. She was prescribed teriparatide, but her pain worsened and she was referred to our hospital. She was diagnosed with fragility fracture of the pelvis (Rommens classification type IVb) and was treated operatively. During the surgery, her thin bladder wall, which was compressed by a displaced pubic fragment, was torn and repaired. This is the first report describing a fragility fracture of the pelvis associated with a bladder rupture. Our treatment led to a successful result.

Outcomes of Resection and Joint-Preserving Arthroplasty for Forefoot Deformities for Rheumatoid Arthritis.

BACKGROUND: We investigated the clinical outcomes of resection and joint-preserving arthroplasty for forefoot deformities in patients with rheumatoid arthritis. METHODS: Sixteen feet of 14 women (average age, 67.1 years; range, 53-82) underwent resection arthroplasty of the metatarsal head (resection group), and 18 feet of 15 women (average age, 61.3 years; range, 40-73) underwent a metatarsophalangeal joint-preserving procedure with shortening oblique metatarsal osteotomies of the lesser toes (joint preservation group). The mean disease duration in the resection and joint preservation groups was 23.6 and 19.1 years, and the average follow-up period was 37.3 and 33.5 months, respectively. The classification of Larsen was used to assess the severity of destruction of the metatarsophalangeal (MTP) joint. Preoperative and postoperative clinical evaluation included Japanese Society for Surgery of the Foot (JSSF) score and postoperative complications. RESULTS: The number of preoperative radiographic destruction of the MTP joints (Larsen grade II, III, IV, and V) was 0, 29, 39, and 12 joints in the resection group and 13, 67, 9, and 1 joints in the joint preservation group. The mean JSSF score improved significantly from 61.3 to 83.9 points in the resection group ( P < .001) and from 62.2 to 90.8 points in the joint preservation group ( P < .001). In the resection group, recurrence of callosities and claw toe deformity was observed in 6 and 3 feet, respectively. In the joint-preserving group, recurrence of callosities and hammer toe deformity was observed in 1 foot each. CONCLUSION: The resection arthroplasty and joint-preserving procedure showed satisfactory clinical outcomes. However, whether both procedures can maintain the good clinical results without the recurrence of forefoot deformity will require longer follow-up. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Shortening Oblique Osteotomy with Screw Fixation for Correction of the Lesser Metatarsophalangeal Joints of Rheumatoid Forefoot.

The metatarsophalangeal (MTP) joints are often and predominantly affected in rheumatoid arthritis. The aim of the current study was to describe surgical techniques of shortening oblique osteotomy for lesser metatarsal bone with screw fixation at the osteotomy site, and to investigate the short-term clinical outcomes of our procedure. Twenty-seven feet (78 toes) of 24 RA patients underwent the shortening oblique osteotomy for the correction of deformity at the lesser MTP joints. The average Japanese Society of Surgery of the Foot (JSSF) standard rating system for the RA foot and ankle scale improved significantly from 59.6 points preoperatively to 88.3 points postoperatively (p＜0.001). Twenty-four feet (89% ) were free from metatarsalgia and symptomatic callosities at the lesser MTP joint after surgery. Our present findings showed satisfactory early clinical outcomes of the shortening oblique osteotomy of the metatarsal bone with screw fixation for RA forefoot.

Postoperative change in the length and extrusion of the medial meniscus after anterior cruciate ligament reconstruction.

PURPOSE: The medial meniscus is a secondary stabilizer of anterior tibial translation in anterior cruciate ligament (ACL)-deficient knees. ACL reconstruction effectively restores an increased anterior tibial translation in the ACL-deficient knee. However, knee osteoarthritis sometimes develops in ACL-reconstructed patients during a long-term follow-up period. We hypothesized that the medial meniscal position would be different between the ACL-deficient and reconstructed knees. The aim of this study was to investigate pre-operative and postoperative location of the medial meniscus in patients who underwent ACL reconstruction. METHODS: ACL-reconstructed knees (28 knees) and normal knees (27 knees) were investigated. Medial tibial plateau length (MTPL) and medial tibial plateau width (MTPW) were determined using radiographic images. Magnetic resonance imaging (MRI)-based medial meniscal length (MML), medial meniscal width (MMW), and medial meniscal extrusion (MME) were measured. Postoperative change in the MML, MMW, and MME were evaluated and compared with those in normal knees. RESULTS: No significant differences between the ACL-deficient (pre-operative) and normal groups were noted. The ACL-reconstructed (postoperative) group showed an increase in the MML, in the percentage of the MML (%MML = 100 MML/MTPL), and in the MME. Significant differences between postoperative and normal groups were observed in the MML, %MML, and MME. MMW and MMW percentage (100 MMW/MTPW) were similar in all groups. CONCLUSIONS: The anteroposterior length and radial extrusion of the medial meniscus increased after ACL reconstruction. Transposition of the medial meniscus may be a possible cause of developing further degenerative knee joint disorders after ACL reconstruction.

A case of surgery for kyphosis of the thoracolumbar spine in an elderly patient with dysphagia.

Here we report a case of surgery for kyphosis of the thoracolumbar spine in an elderly patient, in whom surgery was performed because the patient had developed intractable digestive symptoms. The case was that of a 76-year-old female with complaints of back pain and dysphagia. When videofluoroscopic examination (VF) of swallowing was performed in the cardia of the stomach, images that indicated stagnation and the reflux of food were observed. It was easier for the patient to swallow food in the extension position. We performed corrective fusion of the posterior spine. After the surgery, the kyphosis angle was improved to 27°, the patient's back pain was alleviated, and it became easier for the patient to swallow food. VF also showed that the patient's difficulties with the passage of food had improved. We believe that surgery is a good treatment option for cases of kyphosis with digestive symptoms and deteriorating activities of daily living (ADL), even in the absence of pain and paralysis. VF is also useful for performing evaluations before and after surgery.

Combined use of bFGF and GDF-5 enhances the healing of medial collateral ligament injury.

Basic fibroblast growth factor (bFGF) and growth and differentiation factor (GDF)-5 stimulate the healing of medial collateral ligament (MCL) injury. However, the effect of isolated and combined use of bFGF/GDF-5 remains still unclear. We investigated cellular proliferation and migration responding to bFGF/GDF-5 using rabbit MCL fibroblasts. Rabbit MCL injury was treated by bFGF and/or GDF-5 with peptide hydrogels. Gene expression and deposition of collagens in healing tissues were evaluated. bFGF/GDF-5 treatment additively enhanced cell proliferation and migration. bFGF/GDF-5 hydrogels stimulated Col1a1 expression without increasing Col3a1 expression. Combined use of bFGF/GDF-5 stimulated type I collagen deposition and the reorganization of fiber alignment, and induced better morphology of fibroblasts in healing MCLs. Our study indicates that combined use of bFGF/GDF-5 might enhance MCL healing by increasing proliferation and migration of MCL fibroblasts, and by regulating collagen synthesis and connective fiber alignment.

Anterior cruciate ligament-derived cells have high chondrogenic potential.

Anterior cruciate ligament (ACL)-derived cells have a character different from medial collateral ligament (MCL)-derived cells. However, the critical difference between ACL and MCL is still unclear in their healing potential and cellular response. The objective of this study was to investigate the mesenchymal differentiation property of each ligament-derived cell. Both ligament-derived cells differentiated into adipogenic, osteogenic, and chondrogenic lineages. In chondrogenesis, ACL-derived cells had the higher chondrogenic property than MCL-derived cells. The chondrogenic marker genes, Sox9 and alpha1(II) collagen (Col2a1), were induced faster in ACL-derived pellets than in MCL-derived pellets. Sox9 expression preceded the increase of Col2a1 in both pellet-cultured cells. However, the expression level of Sox9 and a ligament/tendon transcription factor Scleraxis did not parallel the increase of Col2a1 expression along with chondrogenic induction. The present study demonstrates that the balance between Sox9 and Scleraxis have an important role in the chondrogenic differentiation of ligament-derived cells.