Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study.

BACKGROUND: A number of studies have reported that calf muscle atrophy is a common long-term problem after Achilles tendon repair; however, there is still a lack of data concerning early postoperative morphological changes in the calf muscle after surgery. PURPOSE: To investigate changes over time in calf muscle volume and fatty degeneration during 1 year after Achilles tendon repair. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A prospective 1-year serial magnetic resonance imaging study was carried out with 20 patients who underwent tendon repair for unilateral acute Achilles tendon rupture. The magnetic resonance imaging assessment in addition to clinical and functional evaluations was performed at 1, 3, 6, and 12 months after surgery. The muscle volume of the medial and lateral gastrocnemius, soleus, and flexor hallucis longus (FHL) and fatty degeneration of the medial and lateral gastrocnemius and soleus were measured for the calf muscles, and the relative volume and fatty degeneration changes in the affected leg compared with the healthy contralateral leg were calculated as a percentage ([injured/healthy control] × 100) to assess structural changes over time. RESULTS: Muscle volumes of the medial gastrocnemius, lateral gastrocnemius, soleus, and FHL were 92.3%, 92.8%, 84.6%, and 95.9% at 12 months after surgery, respectively. Medial and lateral gastrocnemius and FHL muscle volumes improved over time and recovered to almost equal to that of the healthy side at 12 months after surgery. The soleus muscle volume did not recover significantly over time and was statistically significantly smaller than that of the healthy side at 12 months (P = .029). Fatty degeneration rates of the medial gastrocnemius, lateral gastrocnemius, and soleus were 118.2%, 113.9% and 121.1% at 12 months after surgery, respectively. Fatty degeneration of the medial and lateral gastrocnemius did not change significantly, but there was a statistically significant increase in fatty degeneration of the soleus over time (P < .001). CONCLUSION: Within the triceps surae muscle, the soleus was the most negatively affected by injury and repair for both muscle volume and fatty degeneration. Postoperative management to recover the soleus muscle function before a return to sporting activities should be considered in the future.

Clinical outcomes of surgical treatment for end-stage ankle osteoarthritis in patients aged ≥ 75 years: a multicenter, retrospective study.

BACKGROUND: This study aimed to clarify the clinical outcomes of surgical treatment for end-stage ankle osteoarthritis in patients aged ≥ 75 years and compare these outcomes with those of patients aged < 75 years. METHODS: A total of 148 patients, including 65 who underwent total ankle arthroplasty and 83 who underwent ankle arthrodesis, were retrospectively surveyed. Clinical outcomes were assessed preoperatively and at the last follow-up using the Japanese Society for Surgery of the Foot Hindfoot Scale and a self-administered foot evaluation questionnaire (SAFE-Q). Patient characteristics, including age, sex, body mass index, radiographic severity, and follow-up period, were also assessed. The patients were divided into older (≥ 75 years) and younger (< 75 years) age groups. Improvements in outcomes were then compared between age groups using univariate analysis and analysis of covariance adjusted for patient characteristics. Total ankle arthroplasty and ankle arthrodesis were analyzed separately. RESULTS: All clinical outcome scores improved postoperatively in the older age groups for both procedures. Scores for the pain and pain-related subscale of the SAFE-Q improved by 37 points (p < 0.001) in post-total ankle arthroplasty patients and by 35 points in post-ankle arthrodesis patients (p < 0.001). Furthermore, multivariate analysis showed that the improvements observed in all scores were not different between the older and younger age groups for both post-total ankle arthroplasty and post-ankle arthrodesis patients, except for the SAFE-Q physical functioning subscale score for post-ankle arthrodesis patients. The clinical outcomes improved significantly in post-total ankle arthroplasty and post-ankle arthrodesis patients aged ≥ 75 years. Moreover, these improvements were similar to those observed in patients aged < 75 years. CONCLUSIONS: Surgical treatment of end-stage ankle osteoarthritis can be a viable treatment option, even in elderly patients, and can be expected to improve similarly to younger patients.

The impact of early mobility on functional recovery after hip fracture surgery.

PURPOSE: To examine the effect of early mobility (EM) on functional recovery after hip fracture surgery, and to investigate the potential factors that delay mobility. METHODS: In this retrospective observational study, 110 hip fracture patients were divided into two groups according to the days between surgery and mobility referred to as the EM and the delayed mobility groups. Demographic data, perioperative data, functional outcomes, and discharge destination were compared statistically between the groups using univariate analysis and logistic regression analysis. As a sensitivity analysis, the factors associated with the timing of physiotherapy were also assessed. RESULTS: The EM group had significantly better walking ability and Barthel index (p < 0.05), and home discharge rate (p = 0.004). The factors associated with delayed mobility (odds ratio; 95% confidence interval) were delayed postoperative physiotherapy initiation (3.59; 1.76-7.33), days from admission to surgery (1.23; 1.04-1.46), and postoperative CRP (1.14; 1.01-1.29) and hemoglobin level (0.72; 0.54-0.96). Furthermore, patients who received surgery on the day before any holiday were significantly delayed in physiotherapy intervention (p = 0.006). CONCLUSIONS: This study demonstrated that EM after hip fracture surgery was associated with improving functional recovery and home discharge rate, and early physiotherapy intervention was associated with EM.

Early mobility on the first day after hip fracture surgery was associated with improving walking ability and independence of daily activities on postoperative days 7 and 14, as well as on the time to discharge to own home.Early mobility was specifically associated with the timing of physiotherapy intervention, the days from admission to surgery and the medical condition including perioperative anemia. In particular, patients who received surgery on the day before any holiday were significantly delayed in physiotherapy intervention.

Longitudinal MR quantification of the fat fraction within the supraspinatus and infraspinatus muscles in patients with shoulder pain.

RATIONALE AND OBJECTIVES: Knowing the natural history of fatty degeneration of rotator cuff muscles is important for estimating the risk and rate of progression to cuff tear arthropathy (CTA). The purpose of this study was to investigate the changes in rotator cuff muscle fatty degeneration over time quantitatively in patients treated conservatively for shoulder pain. MATERIALS AND METHODS: Thirty patients with a baseline and follow-up shoulder MRI, including a 2-point Dixon sequence, which were performed at least 1 year apart, were included. We classified patients into 3 groups: "full-thickness tear" (n = 7), "partial-thickness tear" (n = 13), and "no-tear" (n = 10) groups. The fat fraction in the supra- and infraspinatus muscles, and the rate of change in the fat fraction (ΔFfr) were calculated using the formula "fat fraction of follow-up MRI/fat fraction of initial MRI." We investigated the difference in ΔFfr among the 3 groups and the degree of progression to CTA. RESULTS: Statistically significant differences in ΔFfr within the supraspinatus and infraspinatus muscles were found among full-thickness, partial-thickness, and no-tear groups (2.54 vs 1.02 vs 0.75, p < 0.001 and 1.96 vs 1.07 vs 0.73, p = 0.021, respectively). Overall, 71.4% of the full-thickness tear group showed progression of CTA, and 28.6% of the full-thickness tear group needed reverse shoulder arthroplasty within an average follow-up period of 34 months. CONCLUSIONS: MR quantification, together with the knowledge of change in fatty degeneration over time, may be useful for the management of patients with shoulder pain.

Validity, Responsiveness, and Predictive Ability of the Japanese Version of the Cumulated Ambulation Score in Patients with Hip Fracture.

OBJECTIVES: The aim of the current study was to investigate the validity, the responsiveness, and the predictive ability for discharge to own home of the Japanese version of the Cumulated Ambulation Score (CAS-JP). This was achieved by analyzing the CAS-JP after hip fracture surgery at multiple time points until patient discharge. METHODS: Patients who underwent hip fracture surgery were evaluated using CAS-JP, the Barthel Index, and walking ability on postoperative day (POD) 1, 7, and 14 and at discharge. Floor and ceiling effects, responsiveness, and correlations between CAS-JP and other functional outcomes were assessed at each time point. The predictive ability of CAS-JP for discharge to own home was also analyzed using the area under the curve (AUC) of the receiver operating characteristic. RESULTS: A total of 121 patients were included in this study. On POD7, POD14, and at discharge, strong correlations were observed between CAS-JP and the Barthel Index (r=0.81, 0.82, and 0.87, respectively), and between CAS-JP and walking status (r=0.82, 0.81, and 0.76, respectively). CAS-JP had a large effect size (1.64-2.25) and standardized response mean (1.49-1.81). The predictive ability of CAS-JP for discharge to own home, as indicated by the AUCs, were 0.73 (95% CI: 0.62-0.83) on POD7 and 0.74 (95% CI: 0.62-0.86) on POD14. CONCLUSIONS: CAS-JP has sufficient validity and responsiveness as a mobility assessment tool in postoperative hip fracture patients. Furthermore, this study showed that early postoperative mobility status evaluation using CAS-JP can sufficiently predict discharge to own home.

Subchondral insufficiency fracture of the knee: review of current concepts and radiological differential diagnoses.

Subchondral insufficiency fracture of the knee (SIFK) is a common cause of knee joint pain in older adults. SIFK is a type of stress fracture that occurs when repetitive and excessive stress is applied to the subchondral bone. If the fracture does not heal, the lesion develops into osteonecrosis and results in osteochondral collapse, requiring surgical management. Because of these clinical features, SIFK was initially termed "spontaneous osteonecrosis of the knee (SONK)" in the pre-MRI era. SONK is now categorized as an advanced SIFK lesion in the spectrum of this disease, and some authors believe the term "SONK" is a misnomer. MRI plays a significant role in the early diagnosis of SIFK. A subchondral T2 hypointense line of the affected condyle with extended bone marrow edema-like signal intensity are characteristic findings on MRI. The large lesion size and the presence of osteochondral collapse on imaging are associated with an increased risk of osteoarthritis. However, bone marrow edema-like signal intensity and osteochondral collapse alone are not specific to SIFK, and other osteochondral lesions, including avascular necrosis, osteochondral dissecans, and osteoarthritis should be considered. Chondral lesions and meniscal abnormalities, including posterior root tears, are also found in many patients with SIFK, and they are considered to be related to the development of SIFK. We review the clinical and imaging findings, including the anatomy and terminology history of SIFK, as well as its differential diagnoses. Radiologists should be familiar with these imaging features and clinical presentations for appropriate management.

Arthroscopic Bankart Repair and Open Bristow Procedure in the Treatment of Anterior Shoulder Instability With Osseous Glenoid Lesions in Collision Athletes.

BACKGROUND: Traumatic anterior shoulder instability in collision sports athletes often involves osseous glenoid lesions, which make surgical treatment challenging. High redislocation rates have been seen in collision sports athletes treated using arthroscopic Bankart repair. PURPOSE: To investigate the effectiveness of a combined arthroscopic Bankart repair and open Bristow procedure for the treatment of traumatic anterior shoulder instability in collision sports athletes, with a focus on osseous glenoid lesions. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We reviewed 149 shoulders in 141 competitive collision sports athletes (mean ± standard deviation age, 20.1 ± 4.1 years; 8 bilateral cases) who underwent a combined arthroscopic Bankart repair and open Bristow procedure with minimum 2 years of follow-up. Osseous Bankart lesions were arthroscopically reduced and fixed using a coracoid graft. RESULTS: Clinical outcomes as indicated by mean Rowe score improved significantly from 50.0 preoperatively to 98.9 postoperatively (P < .001) at a median follow-up of 3.4 years (range, 2.5-7 years). There were 2 recurrent dislocations (1.3%), both of which had nonunion of the transferred coracoid. Osseous Bankart lesions were observed in 85 shoulders, and osseous glenoid lesions ≥10% of the diameter of the nonoperative side were found in 58 shoulders, including 24 off-track cases. Clinical outcomes were not significantly different between patients with a glenoid defect ≥10% and <10%. Nonunion of the transferred coracoid was observed in 16 shoulders (10.7%), which had inferior Rowe scores; however, we could not define any risk factors for nonunion, including patient characteristics or bone morphology. Postoperative computed tomography performed in 29 patients >1 year after surgery showed successful repair of the osseous glenoid lesions, with a restored glenoid articular surface in all cases. Significant pre- to postoperative increases were seen in glenoid diameter (mean, 13.1% [95% CI, 9.9%-16.3%]; P < .001) and area (mean, 10.6% [95% CI, 8.5%-12.7%]; P < .001). CONCLUSION: A combined arthroscopic Bankart repair and open Bristow procedure improved bone morphology and was a reliable surgical method for treating collision sports athletes with traumatic anterior shoulder instability involving osseous glenoid lesions.

Synthetic poly(2-acrylamido-2-methylpropanesulfonic acid) gel induces chondrogenic differentiation of ATDC5 cells via a novel protein reservoir function.

We previously demonstrated that a synthetic negatively charged poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) gel induced chondrogenic differentiation of ATDC5 cells. In this study, we clarified the underlying molecular mechanism, in particular, focusing on the events that occurred at the interface between the gel and the cells. Gene expression profiling revealed that the expression of extracellular components was enhanced in the ATDC5 cells that were cultured on the PAMPS gel, suggesting that extracellular proteins secreted from the ATDC5 cells might be adsorbed in the PAMPS gel, thereby contributing to the induction of chondrogenic differentiation. Therefore, we created "Treated-PAMPS gel," which adsorbed various proteins secreted from the cultured ATDC5 cells during 7 days. Proteomic analysis identified 27 proteins, including extracellular matrix proteins such as Types I, III, and V collagens and thrombospondin (THBS) in the Treated-PAMPS gel. The Treated-PAMPS gel preferentially induced expression of chondrogenic markers, namely, aggrecan and Type II collagen, in the ATDC5 cells compared with the untreated PAMPS gel. Addition of recombinant THBS1 to the ATDC5 cells significantly enhanced the PAMPS-induced chondrogenic differentiation, whereas knockdown of THBS1 completely abolished this response. In conclusion, we demonstrated that the PAMPS gel has the potential to induce chondrogenic differentiation through novel reservoir functions, and the adsorbed THBS plays a significant role in the induction.

Effect of toe exercises and toe grip strength on the treatment of primary metatarsalgia.

BACKGROUND: The relationship of metatarsalgia and toe function is poorly understood. We investigated the efficacy of toe exercises for the treatment of metatarsalgia. METHODS: Forty-one (56 feet) metatarsalgia patients (mean age ± SD: 63.4 ± 10.6) underwent toe strength measurement. We recorded pre- and post-treatment VAS score, AOFAS score, marble pickup, single-leg standing time (SLST), and compared in two subgroups to evaluate impact of disease duration on treatment outcome. RESULTS: Post treatment, toe plantarflexion strength improved (all p < 0.01); VAS scores decreased (p < 0.01); AOFAS scores, marble pickup, and SLST improved (all p < 0.01). Patients symptomatic for > 1 year had significantly lower changes in VAS scores (p < 0.01). Multivariate analysis showed patients with longer disease duration, and larger body mass index had significantly lower improvement in VAS scores (p = 0.029 and p = 0.036, respectively). Device consistency assessed by ICC was excellent (0.89-0.97). CONCLUSION: Toe function and metatarsalgia are improved by toe exercises, suggesting that they are closely related.

The relationship between high-signal intensity changes in the glenohumeral joint capsule on MRI and clinical shoulder symptoms.

BACKGROUND/OBJECTIVE: High-signal intensity changes in the glenohumeral joint capsule on T2-and proton density-weighted magnetic resonance imaging are known as characteristic finding that is often observed in patients with frozen shoulder. We investigated the associations between high-signal intensity changes in the joint capsule on magnetic resonance imaging and the presence of rotator cuff tears and shoulder symptoms in patients with shoulder pain. METHODS: The medical records of 230 patients with shoulder pain who underwent magnetic resonance imaging at our hospital were reviewed. Patients were divided into three groups according to the presence and/or degree of rotator cuff tears (none, partial, or complete). The frequency of high-signal intensity changes in the joint capsule and its relationship with shoulder symptoms and the severity of rotator cuff tears were assessed. By quantitatively evaluating the intensity on MRI, the ratio between the joint capsule and the long head of the biceps (HSIC ratio) was calculated and compared with 15 healthy subjects. RESULTS: High-signal intensity changes were diagnosed in 165 (72%) patients, and it was significantly associated with night pain and range of motion limitation (p < 0.01). High-signal intensity changes were present in 66 patients (70%) with no rotator cuff tears, in 69 (71%) with partial rotator cuff tears, and in 36 (80%) with complete rotator cuff tears, without differences in their occurrence (p = 0.60), but were significantly associated with night pain in all the groups (p < 0.01) without differences in tear severity (p = 0.63). The ratio in the high-signal intensity changes (HSIC) positive group was approximately six times higher than that in the HSIC-negative and control groups (P < 0.01). Multivariate logistic regression analysis revealed that night pain is significantly associated with high-signal intensity changes (p < 0.01). CONCLUSION: Shoulder pain is a common and reliable clinical finding in patients with high-signal intensity changes, regardless of the presence and/or degree of rotator cuff tears, Such changes may indicate night pain and range of motion limitation in patients.

Integrin α4 mediates ATDC5 cell adhesion to negatively charged synthetic polymer hydrogel leading to chondrogenic differentiation.

Negatively charged synthetic hydrogels have been known to facilitate various cellular responses including cell adhesion, proliferation, and differentiation; however, the molecular mechanism of hydrogel-dependent control of cell behavior remains unclear. Recently, we reported that negatively charged poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) gel induces chondrogenic differentiation of ATDC5 cells via novel protein reservoir function. In this study, we identified the cell adhesion molecules binding to PAMPS gels that act as mechanoreceptors. First, we performed a pull-down assay by particle gels using cell membrane proteins of ATDC5, and found that multiple membrane proteins bound to the PAMPS gel, whereas the uncharged poly(N,N'-dimethylacrylamide) gel as control did not bind to any membrane proteins. Western blot analysis indicated differential binding of integrin (ITG) isoforms to the PAMPS gel, in which the α4 isoform, but not α5 and αv, efficiently bound to the PAMPS gel. ITG α4 knockdown decreased cell spreading of ATDC5 on PAMPS gels, whereas the enhanced expression increased the behavior. Furthermore, ITG α4 depletion suppressed PAMPS gel-induced expression of bone morphogenic protein (BMP) 4 contributing to chondrogenic differentiation, in concordance with the reduction of ERK activation. These results demonstrated that membrane protein binding to PAMPS gels occurred in a charge-dependent manner, and that ITG α4 plays a crucial role in cell spreading on PAMPS gels and acts as a mechanoreceptor triggering cellular signaling leads to chondrogenic differentiation.

Post-operative pain control following arthroscopic rotator cuff repair: peri-articular injection versus interscalene brachial plexus block.

PURPOSE: To compare post-operative pain relief with peri-articular injection (PI) versus interscalene brachial plexus block (IBPB) after arthroscopic rotator cuff repair (ARCR) surgery. METHODS: We retrospectively reviewed 121 consecutive patients undergoing ARCR surgery divided into two groups: the PI group and the IBPB group. We compared complications and self-reported pain score measured using a Numerical Rating Scale (NRS) during the initial 24 hours after surgery. RESULTS: The NRS scores recorded in the recovery room (0), 0.5, and four hours post-operatively were higher in the PI group (n = 38) than the IBPB group (n = 52) (2.1 vs. 0.8, p = 0.014; 1.4 vs. 0.5, p = 0.0069; and 1.3 vs. 0.5, p = 0.012, respectively). However, the NRS scores recorded at 16, 20, and 24 hours post-operatively were lower in the PI group than in the IBPB group (1.4 vs. 3.1, p < 0.0001; 1.4 vs. 3.2, p < 0.0001; and 1.7 vs. 3.2, p = 0.00046, respectively). The incidences of post-operative nausea and temporary numbness in the upper arm were significantly lower in the PI group than in the IBPB group (7.9% vs. 33%, p = 0.0052; and 13% vs. 85%, p < 0.0001, respectively). CONCLUSIONS: Although IBPB provided superior pain control during the initial few hours after ARCR surgery, PI was superior from 16 to 24 hours post-operatively. The rates of side effects, such as nausea and temporary arm numbness, were also lower in the PI group than in the IBPB group.

Effects of Remnant Tissue Preservation on Tunnel Enlargement After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Hamstring Tendon.

BACKGROUND: The effects of remnant tissue preservation on tunnel enlargement after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction have not yet been established. HYPOTHESIS: The preservation of ACL remnant tissue may significantly reduce the degree and incidence of tunnel enlargement after anatomic double-bundle ACL reconstruction, while the remnant-preserving procedure may not significantly increase the incidence of tunnel coalition after surgery. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 79 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 40 patients underwent the remnant-preserving procedure (group P), and the remaining 39 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. All patients were examined using computed tomography and a standard physical examination at 2 weeks and 1 year after surgery. RESULTS: During surgery, the femoral and tibial anteromedial (AM) tunnel sizes in both groups averaged 6.6 and 6.5 mm, respectively. The femoral and tibial posterolateral (PL) tunnel sizes in both groups averaged 6 and 6 mm, respectively. There were no differences in the intraoperative tunnel positions and tunnel sizes between groups. Concerning the femoral AM tunnel, the degree of tunnel enlargement in the oblique coronal and oblique axial views in group P was significantly less than that in group R (P = .0068 and .0323, respectively). Regarding the femoral AM tunnel cross-sectional area, the degree and incidence of tunnel enlargement in group P were significantly less than those in group R (P = .0086 and .0278, respectively). There were no significant differences in tunnel coalition between groups. In each group, there were no significant relationships between tunnel enlargement and each clinical outcome. CONCLUSION: Remnant preservation in anatomic double-bundle ACL reconstruction reduced enlargement of the femoral AM tunnel and did not increase the incidence of tunnel coalition. This is one of the advantages of remnant-preserving ACL reconstruction.

Micro patterning of hydroxyapatite by soft lithography on hydrogels for selective osteoconduction.

Mechanically robust hydrogels are promising biomaterials as artificial supportive tissue. These applications require selective and robust bonding of the hydrogels to living tissue. Recently, we achieved strong in vivo bone bonding of a tough double network (DN) hydrogel, a potential material for use as artificial cartilage and tendon, by hybridizing osteoconductive hydroxyapatite (HAp) in the gel surface layer. In this work, we report micro patterning of HAp at the surface of the DN hydrogel for selective osteoconduction. Utilizing the dissolution of HAp in an acidic environment, the soft lithography technique using an acid gel stamp was adopted to form a high-resolution HAp pattern on the gel. The HAp-patterned gel showed well-regulated migration and adhesion of cells in vitro. Moreover, the HAp-patterned gel showed selective and robust bonding to the rabbit bone tissue in vivo. This HAp soft lithography technique allows for simple and quick preparation of tailor-made osteoconductive hydrogels and can be applied to other hydrogels for selective bone bonding. STATEMENT OF SIGNIFICANCE: Hydrogels, preserving large amount of water, have been studied for next-generation artificial soft tissues. However, fixation of hydrogels to living tissue was unsolved issue for clinical application. Recently, we achieved robust bonding of a tough double network gel to bone in vivo by coating of osteoconductive hydroxyapatite in the gel surface layer. For further progress for practical use, we report the micro patterning of HAp at the surface of the DN hydrogel by using soft lithography technique, to perform selective bonding to only objective area without unnecessary coalescence. The HAp lithography technique is simple, quick and non-toxic method to prepare tailor-made osteoconductive hydrogels and has universality of species of hydrogels.

Comparison Between Isotropic 3-Dimensional Fat-Suppressed T2-Weighted Fast Spin Echo (FSE) and Conventional 2-Dimensional Fat-Suppressed Proton-Weighted FSE Shoulder Magnetic Resonance Imaging at 3-T in Patients With Shoulder Pain.

OBJECTIVE: The aims of this study were to compare isotropic 3-dimensional fat-suppressed T2-weighted fast spin echo (FSE) imaging (T2FS) with 2-dimensional fat-suppressed proton-density-weighted FSE imaging (2D-PDFS) and evaluate feasibility of isotropic 3-dimensional FSE shoulder imaging at 3-T magnetic resonance imaging (MRI). METHODS: Seventy-eight patients who underwent shoulder MRI were evaluated. Three-dimensional T2FS and 2D-PDFS were qualitatively graded for delineation of anatomic structures. In quantitative analysis, mean relative signal intensity and relative signal contrast between each structure of the shoulder were compared. RESULTS: Three-dimensional T2FS showed significantly higher scores for rotator cuff (P = 0.020), lower scores for bone (P < 0.001), and higher relative contrast of rotator cuff to fluid (P < 0.001) and labrum to fluid (P < 0.001) in comparison with 2D-PDFS. No significant difference in relative signal intensity of the rotator cuff, labrum, joint fluid, cartilage, and bone marrow was demonstrated. CONCLUSIONS: Isotropic 3-dimensional FSE MRI has similar image quality and diagnostic performance to conventional 2-dimensional sequence in evaluation of the rotator cuff.

Is the Grafted Tendon Shifted Anteriorly in the Femoral Tunnel at the Postremodeling Phase After Anterior Cruciate Ligament Reconstruction? A Clinical MRI Study.

BACKGROUND: Based on previous in vitro studies, it has been commonly believed that during anterior cruciate ligament (ACL) reconstruction with hamstring tendon, the grafted tendon is shifted anteriorly in the tunnel permanently after the graft is anchored to the tunnel wall. However, this has not been proven by in vivo studies. HYPOTHESIS: At 1 year after anatomic double-bundle ACL reconstruction, the grafted tendons may not be shifted anteriorly in the femoral tunnel but anchored to the bony wall at the center of the tunnel. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Participants consisted of 40 patients who underwent anatomic double-bundle ACL reconstruction. The grafted tendons located in the femoral tunnel were examined 1 year after surgery using 2 different magnetic resonance imaging (MRI) protocols. In the first substudy, with 20 patients, the grafted tendon location was evaluated on an inclined sagittal multiplanar reconstruction (MPR) image taken using a standard T2-weighted protocol. In the second substudy with the remaining 20 patients, tendon location was evaluated on a pure axial MPR image taken using a VISTA (volume isotropic turbo spin echo acquisition) protocol. RESULTS: On the inclined sagittal T2-weighted images of the anteromedial (AM) graft, the anterior width of the newly formed fibrous tissue, which surrounded the tendon graft, was significantly greater than the posterior width (P = .001). The center of the grafted tendon was slightly (mean, 2.5% of the tunnel diameter) but significantly (P = .0310) shifted posteriorly from the tunnel center. On the axial T2-VISTA images, the center of the AM graft was slightly but significantly shifted posteriorly (3.9%; P = .022) and medially (5.5%; P = .002) from the tunnel center. The center of the posterolateral (PL) graft was not significantly shifted to any direction from the center of the tunnel. CONCLUSION: The grafted tendons were not shifted anteriorly in the femoral tunnel 1 year after anatomic double-bundle ACL reconstruction. The PL graft was located approximately at the center of the tunnel outlet, while the AM graft was slightly but significantly shifted posteriorly and proximally.

The Effect of Intraoperative Graft Coverage With Preserved Remnant Tissue on the Results of the Pivot-Shift Test After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Quantitative Evaluations With an Electromagnetic Sensor System.

BACKGROUND: Remnant tissue preservation may be important in improving graft healing after anterior cruciate ligament (ACL) reconstruction, but it has yet to be established whether remnant tissue preservation improves the control of pivot-shift laxity. HYPOTHESIS: The amount of ACL graft coverage with preserved remnant tissue improves the control of pivot-shift laxity, as qualitatively determined with an electromagnetic device. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The 3-dimensional kinematics were evaluated intraoperatively using an electromagnetic sensor system in 38 patients at the time of anatomic double-bundle ACL reconstruction with remnant tissue preservation and again at a minimum of 12 months postoperatively. The magnitude of the peak coupled anterior tibial translation (pCAT) and the maximal acceleration of posterior translation (APT) during the pivot-shift test were evaluated. The degree of graft coverage by remnant tissue was determined arthroscopically at the end of surgery, which was evaluated quantitatively using a scoring system (0-9 points). The relationship between the values during the pivot-shift test and preoperative and intraoperative factors were assessed. RESULTS: The mean (±SD) side-to-side difference of the pCAT (ΔpCAT) was significantly ( P < .0001) improved from 14.0 ± 5.0 mm to 2.6 ± 1.1 mm. Also, the mean side-to-side difference of the APT (ΔAPT) was significantly ( P < .0001) improved from 525.6 ± 99.7 mm/s2 to 32.9 ± 23.6 mm/s2. The mean initial graft coverage score was 5.3 ± 2.6. The correlation analysis demonstrated that the degree of initial graft coverage was significantly correlated with the ΔpCAT ( r = -0.517, P = .0007) and ΔAPT ( r = -0.532, P = .0005). The status of the reconstructed graft at second-look arthroscopic surgery showed no significant correlations with the degree of initial graft coverage or the results of the pivot-shift test. CONCLUSION: The present study demonstrated that the preservation of ACL remnant tissue in anatomic double-bundle ACL reconstruction appears to improve the control of pivot-shift laxity at a minimum of 12 months postoperatively, as measured by an electromagnetic device. This improvement was significantly affected by the degree of intraoperative graft coverage with preserved remnant tissue.

Effects of osteochondral defect size on cartilage regeneration using a double-network hydrogel.

BACKGROUND: There has been increased interest in one-step cell-free procedures to avoid the problems related to cell manipulation and its inherent disadvantages. We have studied the chondrogenic induction ability of a PAMPS/PDMAAm double-network (DN) gel and found it to induce chondrogenesis in animal osteochondral defect models. The purpose of this study was to investigate whether the healing process and the degree of cartilage regeneration induced by the cell-free method using DN gel are influenced by the size of osteochondral defects. METHODS: A total of 63 mature female Japanese white rabbits were used in this study, randomly divided into 3 groups of 21 rabbits each. A 2.5-mm diameter osteochondral defect was created in the femoral trochlea of the patellofemoral joint of bilateral knees in Group I, a 4.3-mm osteochondral defect in Group II, and a 5.8-mm osteochondral defect in Group III. In the right knee of each animal, a DN gel plug was implanted so that a vacant space of 2-mm depth was left above the plug. In the left knee, we did not conduct any treatment to obtain control data. Animals were sacrificed at 2, 4, and 12 weeks after surgery, and gross and histological evaluations were made. RESULTS: The present study demonstrated that all sizes of the DN gel implanted defects as well as the 2.5mm untreated defects showed cartilage regeneration at 4 and 12 weeks. The 4.3-mm and 5.8-mm untreated defects did not show cartilage regeneration during the 12-week period. The quantitative score reported by O'Driscoll et al. was significantly higher in the 4.3-mm and 5.8-mm DN gel-implanted defects than the untreated defects at 4 and 12 weeks (p < 0.05). The 2.5-mm and 4.3-mm DN gel implanted defects maintained relatively high macroscopic and histological scores for the 12-week implantation period, while the histological score of the 5.8-mm DN gel implanted defect had decreased somewhat but statistically significantly at 12 weeks (p = 0.0057). CONCLUSIONS: The DN gel induced cartilage regeneration in defects between 2.5 and 5.8 mm, offering a promising device to establish a cell-free cartilage regeneration therapy and applicable to various sizes of osteochondral defects.

Anisotropic tough double network hydrogel from fish collagen and its spontaneous in vivo bonding to bone.

Soft supporting tissues in the human body, such as cartilages and ligaments, are tough materials and firmly fixed to bones. These soft tissues, once injured, cannot regenerate spontaneously in vivo. Developing tough and biocompatible hydrogels as artificial soft supporting tissues would substantially improve outcomes after soft tissue injury. Collagen is the main rigid component in soft connective tissues which is organized in various hierarchical arrays. We have successfully developed a novel class of collagen fibril-based tough hydrogels based on the double network (DN) concept using swim bladder collagen (SBC) extracted from Bester sturgeon fish. The DN hydrogels, SBC/PDMAAm, are composed of physically/chemically crosslinked anisotropic SBC fibril as the first network and neutral, biocompatible poly(N,N'-dimethylacrylamide) (PDMAAm) as the second network. The anisotropic structure of SBC fibril network, which is well retained in the DN hydrogels, is formed by free injection method, taking advantage of the excellent fibrillogenesis capacity of SBC. The denaturation temperature of collagen is improved in the DN hydrogels. These DN gels possess anisotropic swelling behavior, exhibit excellent mechanical properties comparable to natural cartilage. The 4 weeks implantation of the gels in the osteochondral defect of rabbit knee also shows excellent biomechanical performance in vivo. Furthermore, the hydroxyapatite (HAp) coated DN gels, HAp/SBC/PDMAAm gels, strongly bond to bone after 4 weeks. This new class of collagen-based hybrid DN gels, as soft and elastic ceramics, having good biomechanical performance and strong bonding ability with bone would expand the choice for designing next-generation orthopedic implants such as artificial cartilage, bone defect repair material in the load-bearing region of the body.