The effect of autologous Achilles bursal tissue implants in tendon-to-bone healing of rotator cuff tears in rats.

BACKGROUND: The aim of this study was to investigate the influence of autologous bursal tissue derived from the Achilles bursa on tendon-to-bone healing after rotator cuff tear repair in a rat model. METHODS: A total of 136 Sprague-Dawley rats were randomly assigned to either an untreated or a bursal tissue application group or biomechanical testing and histologic testing after rotator cuff repair. After separating the supraspinatus tendon close to the greater tuberosity, the tendon was reattached either unaltered or with a bursal tissue interposition sewn onto the interface. Immunohistologic analysis was performed 1 and 7 weeks after supraspinatus tendon reinsertion. Biomechanical testing of the tendon occurred 6 and 7 weeks after reinsertion. RESULTS: Immunohistologic results demonstrated a significantly higher percentage of Type II collagen (P = .04) after 1 and 7 weeks in the tendon-to-bone interface using autologous bursal tissue in comparison to control specimens. The bursa group showed a significantly higher collagen I to III quotient (P = .03) at 1 week after surgery in comparison to the 7-week postsurgery bursa groups and controls. Biomechanical assessment showed that overall tendon stiffness (P = .002) and the tendon viscoelasticity in the bursa group (P = .003) was significantly improved after 6 and 7 weeks. There was no significant difference (P = .55) in force to failure between the bursa group and the control group after 6 and 7 weeks. CONCLUSION: Autologous bursal tissue derived from the Achilles bursa and implanted to the tendon-to-bone interface after rotator cuff repair facilitates a faster healing response to re-establish the biologic and biomechanical integrity of the rotator cuff in rats.

Cell Toxicity in Fibroblasts, Tenocytes, and Human Mesenchymal Stem Cells-A Comparison of Necrosis and Apoptosis-Inducing Ability in Ropivacaine, Bupivacaine, and Triamcinolone.

PURPOSE: To analyze the ability of ropivacaine, bupivacaine, and triamcinolone to induce apoptosis and necrosis in fibroblasts, tenocytes, and human mesenchymal stem cells. METHODS: Human dermal fibroblasts, adipose-derived human mesenchymal stem cells (hMSCs), and tenocytes gained from the rotator cuff tendon were seeded with a cell density of 0.5 × 104/cm2. One specimen of ropivacaine, bupivacaine, and triamcinolone was tested separately on the cells with separate concentrations of 0.5%, 0.25%, and 0.125% for each specimen. The negative control received no agent, only a change of medium. The incubation period for each agent was 30 minutes. After a change of medium and 1 hour, 24 hours, and 7 days of incubation, 104 cells were harvested and analyzed via fluorescence-activated cell sorting with double-staining with annexin V and propidium iodide. Statistical analysis to determine significant difference (P < .05) between the groups with SPSS statistics 23 through one-way analysis of variance with a univariate general linear model was performed. RESULTS: Bupivacaine showed necrosis-inducing effects on fibroblasts and tenocytes, with the necrotic effect peaking at 0.5% and 0.25%. Ropivacaine and triamcinolone caused no significant necrosis. Compared with fibroblasts and tenocytes, hMSCs did not show significant necrotic or apoptotic effects after exposure to bupivacaine. Overall, no significant differences in apoptosis were detected between different cell lines, varying concentrations, or time measurements. CONCLUSIONS: Bupivacaine 0.5% and 0.25% have the most necrosis-inducing effects on fibroblasts and tenocytes. Ropivacaine caused less necrosis than bupivaine. Compared with fibroblasts and tenocytes, hMSCs were not affected by necrosis using any of the tested agents. A significant apoptosis-inducing effect could not be detected for the different cell lines. CLINICAL RELEVANCE: Possible cell toxicity raises questions of concern for intra-articular injections using local anesthetics and corticosteroids. The present study demonstrates the necrotic and apoptotic effects of ropivacaine, bupivacaine, and triamcinolone and may give recommendations for intra-articular use of local anesthetics and corticosteroids.

Primary stability of rotator cuff repair: can more suture materials yield more strength?

INTRODUCTION: It remains unclear if the increased biomechanical stability of the double-row repair is solely a result of the technique itself or due to the greater number of utilized materials. This study analyses the various rotator cuff (RC) repair interfaces and the influence of doubling the number of suture knots, stitch techniques and suture anchors on the primary stability of the RC reconstruction. MATERIALS AND METHODS: Established cyclic testing protocols were used to test the primary stability of the knot interface with a Duncan loop and Roeder knot, the tendon-to-suture interface with a single-stitch and Mason-Allen-stitch and the anchor-to-bone interface with OPUS Magnum 2® and BioCorkscrew® anchors. After doubling the materials, the interfaces were tested again and compared to the yielded solitary values. The maximum failure loads (Fmax), clinical failure (CF), system displacement (SD) and modes of failure were recorded. RESULTS: Doubling the amount of knots, stitches and suture anchors improved almost all interface parameters. For example, Fmax, CF and SD of the Roeder knot could be significantly improved from 142.5 N to 256.7 N, from 82.5 N to 155.0 N and from 0.45 mm to 0.20 mm, respectively. The Mason-Allen stitch's Fmax improved from 196.4 N to 324.9 N, and CF from 94.25 N to 139.8 N, with almost identical SD of 0.81 mm and 0.84 mm. Bio-Corkscrew® Fmax improved from 232.5 N to 317.5 N, CF from 182.5 N to 210 N, and SD from 0.85 mm to 0.64 mm. CONCLUSION: Doubling the number of knots, stitches and suture anchors increases the primary stability of the various RC repair interfaces and may result in RC rerupture rate reduction. Furthermore, this study suggests that a suture anchor loaded with two or three sutures may yield the same primary stability as two or three suture anchors loaded with a single suture. This in vitro biomechanical study focuses solely on the rotator cuff interfaces at time zero; the biological healing process was therefore not analysed and requires further investigation. CLINICAL RELEVANCE: Improved primary stability by increased number of suture materials may reduce rate of RC rerupture.

Influence of Temperature on the Biomechanical Stability of Titanium, PEEK, Poly-L-Lactic Acid, and ß-Tricalcium Phosphate Poly-L-Lactic Acid Suture Anchors Tested on Human Humeri In Vitro in a Wet Environment.

PURPOSE: The purpose of this study was to analyze the biomechanical integrity of suture anchors of different materials (titanium, PEEK [polyether ether ketone], poly-L-lactic acid [PLLA], and ß-tricalcium phosphate PLLA) and almost identical design for rotator cuff repair in human humeri positioned in a water bath at room and body temperature undergoing cyclic loading rather than single-pull or static tests. METHODS: Four different anchor models (n = 6) were tested using healthy human cadaveric humeri in a water bath thermostatically regulated at 20°C and 37°C. A cyclic testing protocol was used. The maximum failure load, the system displacement, and the respective mode of failure were recorded. RESULTS: There were no significant differences regarding the maximum failure load values between the 20°C groups and 37°C groups for the 4 different anchor materials. The displacement values for the 20°C groups and 37°C groups also were not statistically significant. Anchor and suture dislocations were the predominant modes of failure; suture ruptures were observed in few cases. CONCLUSIONS: This study shows that there are no significantly relevant differences regarding the maximum failure loads and the displacement values of the tested suture anchor systems in a wet environment at 20°C or 37°C. The temperature differences do not seem to affect the modes of failure either. CLINICAL RELEVANCE: Titanium, PEEK, PLLA, and ß-tricalcium phosphate PLLA suture anchors for rotator cuff repair can be expected-on the basis of this investigation comparing laboratory temperature with body temperature and a wet environment-to perform in vivo similar to in vitro testing.

Revision surgery after third generation autologous chondrocyte implantation in the knee.

PURPOSE: Third generation autologous chondrocyte implantation (ACI) is an established treatment for full thickness cartilage defects in the knee joint. However, little is known about cases when revision surgery is needed. The aim of the present study is to investigate the complication rates and the main reasons for revision surgery after third generation autologous chondrocyte implantation in the knee joint. It is of particular interest to examine in which cases revision surgery is needed and in which cases a "wait and see" strategy should be used. METHODS: A total of 143 consecutive patients with 171 cartilage defects were included in this study with a minimum follow-up of two years. All defects were treated with third generation ACI (NOVACART®3D). Clinical evaluation was carried out after six months, followed by an annual evaluation using the International Knee Documentation Committee (IKDC) subjective score and the visual analogue scale (VAS) for rest and during activity. Revision surgery was documented. RESULTS: The revision rate was 23.4 % (n = 36). The following major reasons for revision surgery were found in our study: symptomatic bone marrow edema (8.3 %, n = 3), arthrofibrosis (22.2 %, n = 8) and partial graft cartilage deficiency (47.2 %, n = 17). The following revision surgery was performed: retrograde drilling combined with Iloprost infusion therapy for bone marrow oedema (8.4 %, n = 3), arthroscopic arthrolysis of the suprapatellar recess (22.2 %, n = 8) and microfracturing/antegrade drilling (47.3 %, n = 17). Significant improvements of clinical scores after revision surgery were observed. CONCLUSION: Revision surgery after third generation autologous chondrocyte implantation is common and is needed primarily in cases with arthrofibrosis, partial graft cartilage deficiency and symptomatic bone marrow oedema resulting in a significantly better clinical outcome.

Does footprint preparation influence tendon-to-bone healing after rotator cuff repair in an animal model?

PURPOSE: The aim of this study was to investigate the influence of footprint spongialization and radiofrequency ablation on rotator cuff repair outcomes compared with an untreated group in a rat model. METHODS: We randomly assigned 189 Sprague-Dawley rats to either a spongialization, radiofrequency ablation, or untreated group. After separation of the supraspinatus tendon from the greater tubercle, the footprint was prepared by removing the cortical bone with a burr (spongialization), was prepared by ablating soft tissue with a radiofrequency ablation device, or was left unaltered (untreated). Biomechanical testing (after 7 weeks, n = 165) and histologic analysis after 1 and 7 weeks (n = 24) followed reinsertion. RESULTS: The mean load to failure was 17.51 ± 4.46 N/mm(2) in the spongialization group, 15.56 ± 4.85 N/mm(2) in the radiofrequency ablation group, and 19.21 ± 5.19 N/mm(2) in the untreated group. A significant difference was found between the spongialization and radiofrequency ablation groups (P = .0409), as well as between the untreated and radiofrequency ablation groups (P = .0014). There was no significant difference between the spongialization and untreated groups (P = .2456). The mean area of fibrocartilage transition, characterized by the presence of type II collagen, was larger after 1 and 7 weeks in the spongialization group (0.57 ± 0.1 mm(2) and 0.58 ± 0.1 mm(2), respectively) and untreated group (0.51 ± 0.1 mm(2) and 0.51 ± 0.2 mm(2), respectively) than in the radiofrequency ablation group (0.11 ± 0.1 mm(2) and 0.4 ± 0.1 mm(2), respectively) with P < .05 and P < .01. CONCLUSIONS: The results of this study show that radiofrequency ablation of the footprint results in a poor biomechanical and histologic outcome in an animal model. No preparation of the footprint has the same effect as spongialization. CLINICAL RELEVANCE: Different techniques of footprint preparation in rotator cuff repair may influence tendon-to-bone healing.

Early resumption of physical activities leads to inferior clinical outcomes after matrix-based autologous chondrocyte implantation in the knee.

PURPOSE: Matrix-based autologous chondrocyte implantation is a well-established operation procedure for full cartilage defects. When to resume physical activity after matrix-based autologous chondrocyte implantation is controversial. Our hypothesis was that early resumption of physical activity leads to a worse clinical outcome after matrix-based autologous chondrocyte implantation in the knee two years post-operatively. Physical activity is defined as any kind of impact sport. METHODS: Forty-four patients with cartilage defects of the knee were treated with matrix-based autologous chondrocyte implantation (Novocart3D). All patients were assessed preoperatively and after a period of 24 months with the University of California Los Angeles (UCLA) Activity score. The return to physical activities or sports after matrix-based autologous chondrocyte implantation was documented. Patients were evaluated using the International Knee Documentation Committee Knee Examination Form and visual analogue scale for pain after 6, 12 and 24 months. RESULTS: Fifty-five percent showed an unchanged level of physical activity in the UCLA Activity score post-operatively. About 35% showed a lower level and 10% a higher level of physical activity. The average return to physical activities or sports after matrix-based autologous chondrocyte implantation procedure was 10.2 months. Patients with a later return of sports after 12 months showed significantly better clinical results after two years. In particular, patients who started practicing impact sport after 12 months post-operatively showed significantly better results. CONCLUSION: Resuming physical activity including impact sports without waiting at least 12 months after the operation leads to inferior outcomes up to 24 months after matrix-based autologous chondrocyte implantation. LEVEL OF EVIDENCE: Level IV.

Graft hypertrophy of matrix-based autologous chondrocyte implantation: a two-year follow-up study of NOVOCART 3D implantation in the knee.

PURPOSE: Graft hypertrophy is a major complication in the treatment for localized cartilage defects with autologous chondrocyte implantation (ACI) using periosteal flap and its further development, Novocart (a matrix-based ACI procedure). The aim of the present study is to investigate individual criteria for the development of graft hypertrophy by NOVOCART 3D implantation of the knee in the post-operative course of 2 years. METHODS: Forty-one consecutive patients with 44 isolated cartilage defects of the knee were treated with NOVOCART 3D implants. Individual criteria and defect-associated criteria were collected. Follow-up MRIs were performed at 3, 6, 12 and 24 months. The NOVOCART 3D implants were measured and classified. The modified MOCART Score was used to evaluate quality and integration of the NOVOCART 3D implants in MRI. RESULTS: Graft hypertrophy was observed in a total of 11 patients at all post-operative time points. We were able to show that NOVOCART 3D implantation of cartilage defects after acute trauma and osteochondritis dissecans (OCD) led to a significantly increased proportion of graft hypertrophy. No other individual criteria (age, gender, BMI) or defect-associated criteria (concomitant surgery, second-line treatment, defect size, fixation technique) showed any influence on the development of graft hypertrophy. The modified MOCART Score results revealed a significant post-operative improvement within 2 years. CONCLUSION: The aetiology of cartilage defects appears to have a relevant influence for the development of graft hypertrophy. Patients, who were treated with NOVOCART 3D implants after an acute event (acute trauma or OCD), are especially at risk for developing a graft hypertrophy in the post-operative course of two years. LEVEL OF EVIDENCE: Case series, Level IV.

UKA can be safely revised to primary knee arthroplasty by using an autologous bone plate from the proximal lateral tibia.

The bone-preservation by UKA in medial osteoarthritis constitutes only an advantage if in the case of revision an unconstrained TKA can be implanted. The aim of this study was to evaluate a revision technique using an autologous bone slice from the lateral to the medial proximal tibia. We report on 17 patients with a mean follow up of 3.1years. Patient's satisfaction and pain, WOMAC- and Oxford-Knee-Score, radiological and clinical knee symptoms/function were assessed. No loosening, wear or implant subsidence could be detected during the follow up. In comparison with results after primary TKA in the literature we found our clinical results to be within the range. The study demonstrates that thismethod is safe and produces good midterm results.

Prevalence of femoro-acetabular impingement in international competitive track and field athletes.

PURPOSE: The aim of our study was to analyse the prevalence of femoro-acetabular impingement (FAI) in national elite track and field athletes compared to peers using magnetic resonance imaging (MRI) and clinical examination including impingement tests. METHODS: A total of 44 participants (22 national elite track and field athletes and 22 non-athletes) underwent an MRI for radiological findings associated with FAI, including alpha angle, lateral centre edge angle (CEA), findings of labral and cartilage lesions. The study group was furthermore investigated by the hip outcome score (HOS) and a clinical hip examination including range of motion (ROM) and impingement tests. RESULTS: Concerning the cam impingement, there was a significant difference measured by mean alpha angle between the athlete group (52.2 ± 7.29°) and the control group (48.1 ± 5.45°, P = 0.004). Eleven athletes showed a cam impingement, while two probands of the control group had a pincer impingement and one a mixed form (P = 0.0217). There was no statistically significant difference concerning the CEA upon evaluating pincer impingement. Seven track and field athletes had a positive impingement test, whereof three had an increased alpha angle >55°. No participant of the control group showed pathological results in the impingement test (P = 0.0121). CONCLUSIONS: MRI evidence and clinical examination suggest that cam impingement is more common in elite athletes in comparison to non-athletes. At a professional level, the intense practice of track and field athletics is susceptible for FAI.

Fentanyl is less toxic on adult human mesenchymal stem cells compared to ropivacaine when used intraarticularly. A controlled in vitro study.

The purpose of this study was to evaluate the toxicity of ropivacaine and fentanyl on adult human mesenchymal stem cells (hMSC). hMSC's were seeded in monolayer triple-flasks and then plated into 96-well plates at a density of 5000 cells per well. After fully aspirating the culture medium, ropivacaine or fentanyl in its corresponding concentration (0.5%, 0.25%, 0.125% for ropivacaine and 0.05%, 0.025%, 0.0125% for fentanyl) or culture medium only was added to each well. After 30 min, the anaesthetic was removed and fresh culture medium was added. hMSCs mitochondrial activity as a marker of cell proliferation and apoptosis marker was evaluated after 1, 24 h and 7 days. Proliferation was significantly decreased after a 30 min exposure to 0.5% and 0.125% ropivacaine, respectively compared to the control group after 24 h (p < 0.001). Simultaneously, apoptosis was significantly induced. Proliferation of hMSC's was decreased after 24 h when exposed to 0.05%, 0.025% and 0.0125% fentanyl (p < 0.001). Apoptosis was only induced 24 h after an exposure to 0.05% fentanyl. Our data suggest that both drugs have a concentration-dependent effect on proliferation in adult hMSC's in vitro. This effect was more distinct with ropivacaine compared to fentanyl. Translating these results into clinical practice, this in vitro study suggests fentanyl as a potentially less toxic analgetic drug for intraarticular application after arthroscopic bone marrow stimulation or rotator cuff repair with comparable to prolonged pain reduction.

Sports activities after medial unicompartmental knee arthroplasty Oxford III-what can we expect?

PURPOSE: Excellent long-term results have been reported for implantation of unicompartmental knee arthroplasty (UKA). In many patients the desire for improvement in function often includes an aspiration to return to sports. The purpose of our study was to evaluate physical activities after medial Oxford-III (Biomet) UKA surgery. METHODS: Patients' physical activity before and after the surgery was assessed using a self reporting questionnaire. We used the Oxford knee scoring system (OKS), the WOMAC-, the Knee society- (KSS) and the UCLA-score to assess postoperative knee function. The mean follow-up was 4.2 years. The female-to-male ratio was 1.3:1. The mean age at surgery was 65.3 years. RESULTS: Of the 131 patients studied 78 participated in some kind of sports before surgery (mean age 64.4 years), while 53 patients did not perform any sports (mean age 66.5 years) (p > 0.05). At follow-up the patients in the active group were significantly younger than the patients in the inactive group (p < 0.05). The majority of patients (80.1 %) returned to their level of sports activity after UKA surgery. Six patients took up sports after surgery while 15 patients stopped their sports. Among the active patients we found a shift from high- towards low-impact sports. The active patients had significantly higher scores for the OKS, KSS, WOMAC and UCLA score. The complication rate was comparable in both groups. CONCLUSION: Our study demonstrates that a high degree of patient satisfaction in terms of sports activity can be achieved using the Oxford-III UKA for medial osteoarthritis.

Navigation in minimally invasive unicompartmental knee arthroplasty has no advantage in comparison to a conventional minimally invasive implantation.

INTRODUCTION: Minimally invasive implantation of unicompartmental knee prostheses can shorten rehabilitation time and lead to better functional results than conventional implantation. Exact positioning of the implant should be achieved, as this is a factor for the long-term survival of the prosthesis, although malpositioning can result due to the poor intraoperative view when using the minimally invasive approach. Navigation of the unicompartmental prosthesis could lead to a better implant positioning without losing the advantages of a minimally invasive approach. MATERIALS AND METHODS: The same unicondylar knee prosthesis was implanted in a total of 40 patients, of whom 20 were implanted using navigation (kinematic navigation) and 20 using a conventional technique. The operating time was assessed in both groups. The orientation of the tibial and femoral implants was assessed radiologically postoperatively. We analysed these results according to the optimal positioning range proposed by the manufacturer. Furthermore, we examined the clinical results with the knee society score (KSS). RESULTS: A good positioning of the prosthesis was observed in both techniques with only 11% of the radiologic measurements out of the proposed optimal range in each group. The operating time was significantly longer in the navigation group (17 min). The KSS did not differ between both groups at a follow-up of 16 resp. 18 months (navigated group: 184 points, conventional group: 178 points). CONCLUSIONS: Navigation did not lead to a better positioning of the prosthesis than the conventional method and the operating time was longer. The clinical results were similar in both groups. The navigation may be a useful help for surgeons performing less unicompartmental knee arthroplasty using a minimally invasive approach.

Rotator Cuff Repair With Autologous Tenocytes and Biodegradable Collagen Scaffold: A Histological and Biomechanical Study in Sheep.

BACKGROUND: Large rotator cuff tears still represent a challenging problem in orthopaedics. The use of tenocytes on biomaterials/scaffolds for the repair of large rotator cuff defects might be a promising approach in the field of tendon regeneration. HYPOTHESIS: Cultivated autologous tenocytes seeded on a collagen scaffold lead to enhanced histological and biomechanical results after rotator cuff repair in a sheep model as compared with unseeded scaffolds in an acute setting. STUDY DESIGN: Controlled laboratory study. METHODS: At the tendon-bone junction of the infraspinatus tendon of the right foreleg of 24 sheep, a 3.5 × 1.5-cm tendon defect was created. Sheep were randomly allocated to group 1, a defect; group 2, where an unseeded collagen scaffold was implanted; or group 3, which received the implantation of a collagen scaffold seeded with autologous tenocytes. Twelve weeks postoperatively, tendon regeneration was examined histologically and biomechanically. RESULTS: The histology of the neotendons of group 3 showed better fiber patterns, a higher production of proteoglycans, and an increased genesis of collagen III in contrast to groups 1 and 2. Immunostaining revealed less tissue dedifferentiation, a more structured cartilage layer, and homogeneous cartilage-bone transition in group 3 in comparison with groups 1 and 2. Biomechanically, the tensile strength of the reconstructed tendons in group 3 (mean load to failure, 2516 N; SD, 407.5 N) was approximately 84% that of the native tendons (mean load to failure, 2995 N; SD, 223.1 N) without statistical significance. A significant difference (P = .0095) was registered between group 1 (66.9% with a mean load to failure of 2004 N; SD, 273.8 N) and the native tendons, as well as between group 2 (69.7% with a mean load to failure of 2088 N; SD, 675.4 N) and the native tendons for mean ultimate tensile strength. In breaking stress, a significant difference (P = .0095) was seen between group 1 (mean breaking stress, 1335 N/mm2; SD, 182.7 N/mm2) and the native tendons, as well as between group 2 (breaking stress, 1392 N/mm2; SD, 450.2 N/mm2) and the native tendons (mean breaking stress, 1996 N/mm2; SD, 148.7 N/mm2). Again, there was no significant difference between group 3 (mean breaking stress, 1677 N/mm2; SD, 271.7 N/mm2) and the native tendons. CONCLUSION: Autologous tenocytes seeded on collagen scaffolds yield enhanced biomechanical results after tendon-bone reconstruction as compared with unseeded scaffolds in an acute setting. Biomechanical results and histological outcomes were promising, showing that the use of autologous tenocytes with specific carrier matrices could be a novel approach for repairing rotator cuff tears. CLINICAL RELEVANCE: This study supports the use of tenocytes and scaffolds for improving the quality of tendon-bone regeneration.

Suture anchor fixation strength in osteopenic versus non-osteopenic bone for rotator cuff repair.

INTRODUCTION: Rotator cuff tears are increasing with age. Does osteopenic bone have an influence on the pullout strength of suture anchors? MATERIALS AND METHODS: SPIRALOK 5.0 mm (DePuy Mitek), Super Revo 5 mm and UltraSorb (both ConMed Linvatec) suture anchors were tested in six osteopenic and six healthy human cadaveric humeri. Incremental cyclic loading was performed. The ultimate failure load, anchor displacement, and the mode of failure were recorded. RESULTS: In the non-osteopenic bone group, the absorbable SPIRALOK 5.0 mm achieved a significantly better pullout strength (274 N +/- 29 N, mean +/- SD) than the titanium anchor Super Revo 5 mm (188 N +/- 34 N, mean +/- SD), and the tilting anchor UltraSorb (192 N +/- 34 N, mean +/- SD). In the osteopenic bone group no significant difference in the pullout strength was found. The failure mechanisms, such as anchor pullout, rupture at eyelet, suture breakage and breakage of eyelet, varied between the anchors. CONCLUSION: The present study demonstrates that, in osteopenic bone, absorbable suture anchors do not have lower pullout strengths than metal anchors. In normal bone, the bioabsorbable anchor in this study even outperformed the non-absorbable anchor.

Biomechanical testing of a new knotless suture anchor compared with established anchors for rotator cuff repair.

Various suture anchors are available for rotator cuff repair. For arthroscopic application, a knotless anchor was developed to simplify the intra-operative handling. We compared the new knotless anchor (BIOKNOTLESStrade mark RC; DePuy Mitek, Raynham, MA) with established absorbable and titanium suture anchors (UltraSorbtrade mark and Super Revo 5mmtrade mark; ConMed Linvatec, Utica, NY). Each anchor was tested on 6 human cadaveric shoulders. The anchors were inserted into the greater tuberosity. An incremental cyclic loading was performed. Ultimate failure loads, anchor displacement, and mode of failure were recorded. The anchor displacement of the BIOKNOTLESStrade mark RC (15.3 +/- 5.3 mm) after the first cycle with 75 N was significantly higher than with the two other anchors (Super Revo 2.1 +/- 1.6 mm, UltraSorb: 2.7 +/- 1.1 mm). There was no significant difference in the ultimate failure loads of the 3 anchors. Although the Bioknotlesstrade mark RC indicated comparable maximal pullout strength, it bares the risk of losing contact between the tendon-bone-interface due to a significantly higher system displacement. Therefore, gap formation between the bone and the soft tissue fixation jeopardizes the repair. Bioknotlesstrade mark RC should be used in the lateral row only when a double row technique for rotator cuff repair is performed, and is not appropriate for rotator cuff repair if used on its own.

Does total joint arthroplasty impair erectile function?

INTRODUCTION: Sexuality is an important factor in quality of life (QoL) and was reported to improve after total joint arthroplasty (TJA). However, one study group found evidence regarding a high rate of impaired erectile function of about 20% in male patients after TJA. As erectile dysfunction is a serious matter of concern and there are no data explaining this observation sufficiently, the purpose of this study was to revaluate the erectile function in patients after TJA. MATERIAL AND METHODS: All consecutive male patients scheduled for TJA were enrolled in this prospective study. Evaluation was performed pre- and 6 months postoperatively with the International Index of Erectile Function (IIEF-5) questionnaire. One hundred and fifty-nine patients fulfilled the inclusion criteria, and 51 patients wished not to take part in the study. RESULTS: From the 108 patients who were included prior to surgery, 101 (94%) were available at the 6-month follow-up. In those patients, the preoperative erectile function was normal in 38 (24.0 ±1.1), impaired in 45 (14.7 ±6.5) and with no function in 18 patients. No significant difference in the pre- (15.4 ±9.3) and postoperative (15.3±9.2) IIEF-5 score was observed (p = 0.59) in the total group. Similarly, subgroup analysis revealed no significant difference in patients with total hip arthroplasty (p = 0.58), total knee arthroplasty (p = 0.37) or > 70 years (p = 0.08). CONCLUSIONS: The previously reported high rate of impaired erectile function after TJA of the lower extremity could not be confirmed. Total joint arthroplasty remains a safe procedure in terms of postoperative erectile function.

Migration of Mesenchymal Stem Cells of Bursal Tissue after Rotator Cuff Repair in Rats.

Purpose The purpose of this study is to verify migration of mesenchymal stem cells of bursal tissue into the healing site after rotator cuff repair in rats. Methods Fischer rats and green fluorescent protein (GFP)-transgenic rats were used. Bursal tissue from GFP rats was isolated and transplanted into tendon repair sites in Fischer rats. We examined the histology of the rotator cuff and the proportion of GFP-positive cells in the repaired rotator cuff 1, 3, and 6 weeks after surgery. Results Cell migration was observed during the third and sixth week after surgery. We also found mesenchymal stem cells and formed bursal cluster patterns in the repaired rotator cuff tendons. Conclusion Mesenchymal stem cells migrated from bursal tissue and infiltrated the repaired rotator cuff tendons. Clinical Relevance Mesenchymal stem cells from bursal tissue can contribute to the healing progress of the repaired rotator cuff.

The Primary Stability of a Bioabsorbable Poly-L-Lactic Acid Suture Anchor for Rotator Cuff Repair Is Not Improved with Polymethylmethacrylate or Bioabsorbable Bone Cement Augmentation.

BACKGROUND: The incidence of osteoporosis and rotator cuff tears increases with age. Cement augmentation of bones is an established method in orthopedic and trauma surgery. QUESTIONS/PURPOSES: This study analyses if polymethylmethacrylate or bioabsorbable cement can improve the primary stability of a bioabsorbable suture anchor in vitro in comparison to a non-augmented suture anchor in osteoporotic human humeri. METHODS: The trabecular bone mineral density was measured to ensure osteopenic human specimens. Then the poly-l-lactic acid Bio-Corkscrew® FT was implanted in the greater tuberosity footprint with polymethylmethacrylate Refobacin® cement augmentation (n = 8), with Cerament™ Bone Void Filler augmentation (n = 8) and without augmentation (n = 8). Using a cyclic testing protocol, the failure loads, system displacement, and failure modes were recorded. RESULTS: The Cerament™ augmented Bio-Corkscrew® FT yielded the highest failure loads (206.7 N), followed by polymethylmethacrylate Refobacin® augmentation (206.1 N) and without augmentation (160.0 N). The system displacement was lowest for Cerament™ augmentation (0.72 mm), followed by polymethylmethacrylate (0.82 mm) and without augmentation (1.50 mm). Statistical analysis showed no significant differences regarding the maximum failure loads (p = 0.1644) or system displacement (p = 0.4199). The main mode of failure for all three groups was suture slippage. CONCLUSION: The primary stability of the Bio-Corkscrew® FT is not influenced by bone cement augmentation with polymethylmethacrylate Refobacin® or with bioabsorbable Cerament™ in comparison to the non-cemented anchors. The cement augmentation of rotator cuff suture anchors in osteoporotic bones remains questionable since biomechanical tests show no significant advantage.