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Introduction: Patellar instability can be considered as a rapidly increasing musculoskeletal subject of interest. It is now well accepted that multiple factors can produce this pathological condition, isolated, but more often in concert. One major static compound is found to be in trochlear dysplasia. It has been stated that the form of the trochlear surface is primary and genetically bilaterally determined already before use. According to these data, recurrent dislocation of the patella has been described as a hereditary disease with autosomal dominant transmission. Against this assumption, we hypothesize that subjects may devise a flattened trochlea when there is no significant biomechanical interplay and thus input between the patella and the distal femur during developmental growth; according to the assumption form follows function., Presentation of Case: In this context, we report the case of a 16-year old male who previously suffered from a traumatic patellar dislocation during sporting activity in his below-knee amputated lower extremity, which occured at age of 18 months. The patient was allocated with a high-grade trochlear dysplasia in his previously amputated limb, while presenting a normal trochlear shape at his healthy contralateral leg., Discussion: This rare case therefore reprents the history of an individuum with identic genetic predisposition and different biomechanical influences during childhood, which makes it of high clinical interest. In presence of trochlear dysplasia the patient suffered reluxation and concurrent subjective instability on the lower limb affected by the amputation which was treated with medial patellofemoral ligament (MPFL) plasty using an autologous gracilis graft., Conclusion: One has to consider that a certain biomechanical input may be required for the development of a physiologic trochlear groove., (Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: The purpose of this study was to evaluate the mid- and long-term efficacy of the arthroscopic patellar release (APR) in a representative number of competitive athletes., Methods: This prospective study included 35 competitive athletes who underwent APR for treatment of chronic refractory patellar tendinopathy. The minimum follow-up period was 24 months. Preoperatively and at follow-up, we measured the Swedish Victorian Institute of Sport Assessment for Patella (VISA-P) and modified Blazina score for assessment of functional outcome. The patients rated their subjective knee function (0% to 100%) and maximum pain during exercise on a visual analog scale (0 to 10 points). We inquired about time required for full return to sports., Results: Thirty athletes (27 male individuals, 3 female individuals) were available for clinical examination after a mean follow-up period of 4.4 years (σ = 3.0 years). The follow-up rate was 30 of 35 (86%). Mean age at surgery was 27.6 years (σ = 7.4). The mean VISA-P score improved from 57.3 (σ = 11.4) to 95.1 (σ = 8.2) and the mean Blazina score improved from 4.0 (σ = 0.8) to 0.3 (σ = 0.7). Average subjective knee function improved from 48.8% (σ = 18.5%) to 90.5% (σ = 9.8%). The mean pain level decreased from 5.7 (σ = 1.1) to 0.6 (σ = 1.2%). All changes were significant (P < .01). Twenty-three (76.7%) athletes were able to perform sports at previous levels without any symptoms. The mean time required for full return to sports was 4.4 months (1.5 to 12.0 months; σ = 3.3). Less pronounced symptoms recurred in 3 (10%) athletes., Conclusions: After APR, 97% of patients obtained excellent or good functional outcomes with a mean follow-up of 4.4 years. Three of 4 athletes achieved asymptomatic previous sports levels, returning to full sports at an average of 4.4 months. Symptoms partially recurred in 10% of participants., Level of Evidence: Level IV: prospective therapeutic case series., (Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Autologous chondrocyte implantation (ACI) is an established two-step procedure for the treatment of full-thickness cartilage defects of the knee. Cartilage harvest from the affected knee joint represents the first step of this procedure and is essential for further in vitro expansion of autologous chondrocytes. Nevertheless, the cartilage biopsy process itself is underrepresented in the scientific literature and currently there is only a limited amount of data available addressing this process. Biopsy location as well as the technique itself and instruments used for cartilage collection are not well defined and only little standardisation can be found. The article describes the relevant aspects of the biopsy in the context of ACI with regard to the literature available. Follow-up studies to better define and standardise the cartilage biopsy process are thus required., (Georg Thieme Verlag KG Stuttgart · New York.)

Objective: To explore the effect of shifting in vitro culture conditions regarding cellular passage and onset of loading within matrix-associated bovine articular chondrocytes cultured under free-swelling and/or dynamical loading conditions on general chondrocyte maturation., Methods: Primary or passage 3 bovine chondrocytes were seeded in fibrin-polyurethane scaffolds. Constructs were cultured either free-swelling for 2 or 4 weeks, under direct mechanical loading for 2 or 4 weeks, or free swelling for 2 weeks followed by 2 weeks of loading. Samples were collected for glycosaminoglycan (GAG) quantification, mRNA expression of chondrogenic genes, immunohistochemistry, and histology., Results: Mechanical loading generally stimulated GAG synthesis, up-regulated chondrogenic genes, and improved the accumulation of matrix in cell-laden constructs when compared with free-swelling controls. Primary chondrocytes underwent more effective cartilage maturation when compared with passaged chondrocytes. Constructs of primary chondrocytes that were initially free-swelling followed by 2 weeks of mechanical load (delayed) had overall highest GAG with strongest responsiveness to load regarding matrix synthesis. Constructs that experienced the delayed loading regime also demonstrated most favorable chondrogenic gene expression profiles in both primary and third passage cells. Furthermore, most intense matrix staining and immunostaining of collagen type II and aggrecan were visualized in these constructs., Conclusions: Primary chondrocytes were more effective than passage 3 chondrocytes when chondrogenesis was concerned. The most efficient chondrogenesis resulted from primary articular chondrocytes, which were initially free-swelling followed by a standardized loading protocol.

Background: Currently, no clinical midterm results have been reported on arthroscopically assisted reduction of the acutely dislocated acromioclavicular (AC) joint using suture-button devices for fixation., Hypothesis: Athroscopically assisted reduction of the acutely dislocated AC joint yields satisfactory clinical outcomes without loss of reduction, clavicle migration, or AC joint degeneration at midterm follow-up evaluation., Study Design: Case series; Level of evidence, 4., Methods: The clinical and radiographic outcomes of 23 of 30 consecutive patients (21 men, 2 women) who underwent anatomic reduction for acute AC joint dislocation using 2 suture-button devices between 2006 and 2007 were reviewed. Radiographic evaluation was performed by measurement of coracoclavicular (CC) distance and AC displacement. Clinical evaluation included a visual analog scale (VAS) for pain, the Constant score, the simple shoulder test, and the Short Form-36. Previously, this same patient collective was reviewed after 2 years of follow-up using similar methods., Results: All 23 patients were available for midterm follow-up examination 58 months postoperatively. There were 3 Rockwood type III, 3 type IV, and 17 type V acromioclavicular joint separations. Mean ± SD follow-up was 58 ± 5.6 months (range, 51-67 months). Most patients (96%) remained very satisfied or satisfied with the procedure outcome. The VAS and Constant score improved significantly when compared with baseline (0.3 ± 0.6 and 91.5 ± 4.7 at 58 months postoperatively vs 4.5 ± 1.9 and 34.5 ± 6.9 at baseline) and remained essentially unchanged when compared with the 2-year outcome scores (0.3 ± 0.6 and 91.5 ± 4.7 at 58 months postoperatively vs 0.25 ± 0.5 and 94.3 ± 3.2 at 2 years). Radiographs showed 8 radiographic failures (undercorrection, posterior displacement, or both) and 4 additional overcorrections of the CC distance. When comparing with 24-month data, 17 of 20 radiographs remained unchanged; 1 case of previous overcorrection drifted into normal AC alignment and 2 cases increased in posterior subluxation of the clavicle., Conclusion: Arthroscopically assisted reduction of the acutely dislocated AC joint provides satisfactory clinical results 58 months after surgery. Compared with the baseline, all patients improved significantly. Two of 23 patients revealed an increased posterior dislocation compared with evaluation 24 months after surgery. No further migration of the clavicle or AC joint degeneration was observed.

Background: Effective mesenchymal stem cell chondrogenesis can be accomplished by using a tailored mechanical-biochemical stimulus. To achieve this requires parallel suppression of hypertrophy and osteogenesis., Materials & Methods: We compared the effects of isolated bioreactor stimulation, isolated growth factor (TGF-β1 or IGF-1) application and their combined stimulation on human bone marrow-derived mesenchymal stem cells cultured within 3D scaffolds. Free-swelling cell-matrix constructs underwent identical growth factor stimulation for control., Results: Mechanical stimulation provoked stronger chondrogenic differentiation than free-swelling culture. Chondrogenesis by the addition of TGF-β1 was enhanced compared with single physical stimulation. There were no such effects under the influence of IGF-1 alone. Composite application of multiaxial mechanical stimulation plus TGF-β1 and IGF-1 not only triggered the strongest chondrogenesis overall, but also the strongest hypertrophy and osteogenesis., Conclusion: Bioreactor-induced chondrogenic differentiation of human mesenchymal stem cells can be effectively enhanced by growth factor addition, while the partially effective suppression of unwanted signs of endochondral ossification requires further scientific input.

Case Series: Level of evidence, 4., Background: Arthroscopic microfracture of chondral defects across the knee joint is a frequent treatment modality. There is only limited information on the clinical outcome in patients without previous surgery and single lesions., Purpose: Evaluation of clinical outcome following microfracture in patients without previous surgery and single lesions and identification of prognostic factors., Methods: Inclusion criteria were patients with single-lesion knee joint first-line microfracturing at minimum 2 years postoperatively. Charts were reviewed to identify patient and defect characteristics. Clinical outcome was evaluated by IKDC and Lysholm knee scores, Tegner activity scale and a numeric analogue scale (NAS) for function and pain (10 = highest possible function, no pain)., Results: Totally, 145 patients (age at operation 47.92 ± 15.7) met inclusion criteria. Average defect size was 2.7 ± 1.9 cm(2). Postoperatively, IKDC was 73.1 ± 18.5, Lysholm 77.6 ± 19.1, Tegner 4.5 ± 1.7, NAS pain 6.5 ± 2.6 and NAS function 6.4 ± 2.3. Significantly better clinical outcome was observed in male patients than in female patients. Regression analysis including all patient and defect characteristics highlighted that singly the parameter shorter symptom duration (P = 0.018) significantly predicted an improved postoperative clinical outcome., Conclusion: Microfracturing results in a satisfying clinical outcome, but no full recovery in patients without previous surgery and single lesions. Specific parameters facilitate outcome prognosis and therefore may aid in indicating surgery.

Purpose: There is only limited information on those patients who fail following microfracture treatment at the knee joint. Evaluation was made of factors associated with treatment failure and clinical outcome assessment among this collective., Methods: The study included a total of 560 patients who had previously undergone microfracture for the treatment of symptomatic knee joint cartilage lesions. For the remainder of this study, inclusion criteria were patients that underwent reoperation at the initially operated knee joint (index knee) due to symptoms related to the primary site of microfracture intervention (failure patients) with a minimum postoperative follow-up of 2 years. The remaining cohort of patients served as internal control (non-failure patients). Chart reviews were performed to identify patient and defect characteristics. Patients were evaluated for postoperative Lysholm knee scores, Tegner activity scale, as well as preoperative and postoperative numeric analogue scales (NAS) for function and pain (10 = highest possible function, no pain)., Results: A total of 454/560 (81.1 %) subjects were completely evaluated. Overall, 123/454 patients (26.9 %) (age at operation 43.9 ± 14.1 years, 56 female, BMI 25.8 ± 3.6, 30 smokers, 61.1 ± 68.3 month symptom duration, postoperative follow-up 5.0 ± 2.1) met the inclusion criteria. The postoperative Lysholm score was 63.0 ± 24.6 and the Tegner score was 4.0; NAS function improved from 2.8 ± 1.8 to 4.8 ± 2.2 (P < 0.001), and NAS pain improved from 3.2 ± 2.1 to 5.0 ± 2.4 (P < 0.001). Exclusively, the overall defect size/knee joint was smaller (P = 0.006), postoperative follow-up was longer (P = 0.002), and existense of previous surgery (77.2 vs. 51.6 %, P < 0.001) was more frequent in failure subjects when comparing to non-failure patients (n = 331). The overall clinical outcome among failure subjects was significantly worse when comparing to non-failure subjects. Regression analysis identified that lower preoperative NAS values, being a smoker, and patello-femoral lesions were associated with a higher probability of reoperation., Conclusion: Within the collective presented here, microfracturing was associated with a high frequency of reoperation. Clinical outcome is worse when compared with that of patients without reoperation. Specific parameters can be identified that increase the eventuality of failure following microfracture treatment., Level of Evidence: IV.

Background: The purpose of the study was to report early functional and radiographic results of a small series of patients who underwent autologous chondrocyte transplantation-collagen membrane seeding (ACT-Cs) for focal chondral defects of the shoulder., Methods: The outcome of 4 consecutive male patients (mean age, 29.3 ± 6.2 years; range, 21-36 years) who underwent ACT-Cs for treatment of large symptomatic glenohumeral cartilage defects was retrospectively evaluated with clinical and radiographic measures at a mean of 41.3 ± 24.9 months (range, 11-71 months) after surgery. The evaluation included a visual analog scale for pain, the Constant score, the American Shoulder and Elbow Surgeons shoulder index, the Rowe score, and a satisfaction scale. Magnetic resonance imaging evaluation was performed according to the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system., Results: There were 3 humeral full-thickness cartilage defects (each 6.0 cm(2)) and 1 glenoid full-thickness cartilage defect (2.0 cm(2)). The mean postoperative visual analog scale score (0.3 of 10), the mean unweighted Constant score (83.3 ± 9.9), and the mean American Shoulder and Elbow Surgeons index (95.3 ± 8.1) were representative of satisfactory shoulder function. The Magnetic Resonance Observation of Cartilage Repair Tissue score was indicative of satisfactory defect coverage with signs of fibrocartilaginous repair tissue., Conclusions: Autologous chondrocyte transplantation at the glenohumeral joint is a remote option for young adults with symptomatic, isolated, large-diameter cartilage lesions. Potential complications as a result of the open approach and 2-step procedure have to be considered carefully. Long-term data, larger patient populations, and randomized studies are required to determine the potential for chondrocyte transplantation techniques to be standard procedure for treatment of symptomatic, large-diameter, full-thickness cartilage defects in the glenohumeral joint., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Even though operative microfracture is the most frequent method for treatment of limited knee joint cartilage lesions among adults, data about ouctome in children and adolescents are rare. We performed a retrospective chart review and telephone interview to analyze for the clinical outcome following knee joint cartilage defect microfracturing among 10 children. Mean postoperative Lysholm was 92.1±9.9 and Tegner was 7.0±1.9. Clinical outcome differed across knee joint regions, as well as in dependence of varying pre-operative symptom duration, although this was not significant. Regression analysis did not reveal a significant impact of patient or defect characteristics on clinical outcome. Arthroscopic microfracturing for treatment of limited size symptomatic knee joint cartilage defects among children and adolescents is considered a reasonable surgical option. However, long-term outcome and larger patient cohorts are required.

Background: Several factors influence clinical outcome after autologous chondrocyte implantation (ACI) for the treatment of cartilage defects of the knee joint., Hypothesis/purpose: The aim of the present study was to investigate the influence of cell quality on clinical outcome after ACI. The hypothesis of the authors was that cell quality at the time of transplantation influences clinical outcome after ACI for cartilage defects., Study Design: Cohort study; Level of evidence, 3., Methods: A total of 80 patients were included in the present study. Knee function was assessed before surgery as well as 6, 12, and 24 months after ACI using standard instruments (International Knee Documentation Committee [IKDC], Lysholm, and Tegner scores). Cell quality was evaluated by determination of antigen expression of CD44 expression, aggrecan, collagen type II, and cell viability. A linear regression analysis including preoperative knee function, defect size, defect location, defect origin, body mass index, patient age, and other parameters was performed to evaluate the influence of these parameters on postoperative knee function., Results: Preoperative IKDC score increased from 49.6 ± 13.8 points to 75.5 ± 14.6 points at 24 months (P < .05). Postoperative IKDC score at 6, 12, and 24 months was significantly influenced by collagen type II expression, CD44 expression, and cell viability (all P < .05). No correlation between aggrecan and outcome was found. Quantitative influence of individual factors differed between different time points., Conclusion: Cell quality seems to be one of many factors that influences clinical outcome after ACI in patients with cartilage defects of the knee joint. It constitutes one aspect among various others affecting clinical outcome.

Aim: Since its introduction in 1994, autologous chondrocyte implantation (ACI) has become an established surgical treatment for symptomatic isolated cartilage defects of the knee. Success rates vary between 80 and 95% and the clinical outcome seems to depend on various individual factors. The aim of the present review article is to summarise factors that affect clinical outcome following ACI for treatment of symptomatic cartilage defects of the knee based upon the scientific literature available on this topic., Methods: The present publication represents a non-systematic review including publications which were considered relevant describing factors that influence clinical outcome following ACI for treatment of symptomatic full thickness cartilage defects of the knee. In order to identify relevant literature concerning complications following cartilage repair, medical databases including "medline", "ovid" and "web of science" were searched for the terms "autologous chondrocyte implantation", "autologous chondrocyte transplantation", "prognostic factor", "clinical outcome", "cartilage repair", "cartilage defect" and "cartilage regeneration". The literature search was performed in April 2010., Results: Factors that influence clinical outcome following ACI for treatment of cartilage defects of the knee include patient-specific parameters on the one hand, such as body mass index, nicotine abusus, patients age, prior surgical treatment, duration of symptoms and more, and defect characteristics such as containment, defect location, defect size, number of defects treated, on the other hand. Furthermore, surgical technique, cell quality and rehabilitation seem to significantly influence the clinical outcome following autologous chondrocyte implantation. Among all factors identified as relevant for clinical outcome, some of these parameters are fixed and cannot be changed by either the surgeon nor the patient, while others can be influenced and even changed during the treatment and rehabilitation of a patient who underwent ACI., Conclusion: Knowledge of all relevant parameters that influence clinical outcome following ACI is essential in order to achieve an optimal clinical outcome in patients with cartilage defects of the knee. This paper presents a review of the scientific literature available which focuses on the questions as to what parameters influence the outcome of a patient following ACI for treatment of cartilage defects of the knee. No isolated factors could be identified that influence the outcome following ACI alone, but it seems that clinical outcome is influenced by many different parameters. These parameters should be considered carefully, at the time of decision about what kind of treatment is applied. Furthermore, the patient should be informed especially about those parameters which can be influenced by him-/herself in order to create good prerequisites for the surgical treatment., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background: Autologous chondrocyte implantation (ACI) is a well-established treatment option for isolated cartilage defects of the knee joint, providing satisfying outcome. However, cases of treatment failure with the need for surgical reintervention are reported; typical patient's individual and environmental risk factors have previously not been described., Hypothesis: The need for reintervention after ACI is associated with specific preoperative detectable individual risk factors., Study Design: Cohort study; Level of evidence, 3., Methods: A total of 413 patients following ACI (first, second, and third generation) were filtered for those who required revision surgery during their follow-up time (2-11.8 years). Factors were analyzed that might have significant effects on increased revision rate. Using preoperatively collected data, all patients were grouped according to 12 standard prognostic factors. Apart from odds ratio and Pearson χ(2) test, statistical analysis of risk factors was performed with multivariate binary logistic regression models and Cox regression, the method of choice for survival time data., Results: After a follow-up of 4.4 ± 0.9 years (limited to 5 years), a total of 88 patients (21.3%) had undergone surgical revision. The time to revision surgery was 1.8 ± 1.1 years. Four prognostic factors associated with a significantly higher risk for reintervention were detected: (1) female gender (Cox survival fit: P = .033), (2) previous surgeries of the affected joint (P = .002), (3) previous bone marrow stimulation (P = .041), and (4) periosteum patch-covered ACI (P = .028). An influence of patient age, body mass index (BMI), defect number, defect size, lesion origin, lesion location, parallel treatment, or smoking on the risk for reintervention could not be observed., Conclusion: The study identifies clear facts that significantly increase the risk of revision surgery. These facts can be easily obtained preoperatively and may be taken into consideration when indicating ACI.

Background: Surgical repair of massive rotator cuff tears is associated with less favorable clinical results and a higher retear rate than repair of smaller tears, which is attributed to irreversible degenerative changes of the musculotendinous unit., Materials and Methods: During the study period, 25 consecutive patients with a massive rotator cuff tear were enrolled in the study and the tears were repaired with an open suture anchor repair technique. Preoperative and postoperative clinical assessments were performed with the Constant score, the simple shoulder test (SST) and a pain visual analog scale (VAS). At the final follow-up, rotator cuff strength measurement was evaluated and assessment of tendon integrity, fatty degeneration and muscle atrophy was done using a standardized magnetic resonance imaging protocol., Results: The mean follow-up period was 70 months. The mean constant score improved significantly from 42.3 to 73.1 points at the final follow-up. Both the SST and the pain VAS improved significantly from 5.3 to 10.2 points and from 6.3 to 2.1, respectively. The overall retear rate was 44% after 6 years. Patients with an intact repair had better shoulder scores and rotator cuff strength than those with a failed repair, and also the retear group showed a significant clinical improvement (each P<0.05). Rotator cuff strength in all testing positions was significantly reduced for the operated compared to the contralateral shoulder. Muscle atrophy and fatty infiltration of the rotator cuff muscles did not recover in intact repairs, whereas both parameters progressed in retorn cuffs., Conclusions: Open repair of massive rotator tears achieved high patient satisfaction and a good clinical outcome at the long-term follow-up despite a high retear rate. Also, shoulders with retorn cuffs were significantly improved by the procedure. Muscle atrophy and fatty muscle degeneration could not be reversed after repair and rotator cuff strength still did not equal that of the contralateral shoulder after 6 years., Level of Evidence: Level IV.

Matrix-assisted chondrocyte transplantation (m-ACI) still lacks any standardization in its execution in terms of cell passage (P), cell yield (C) and in vitro membrane-holding time (T). It was the goal of this study to analyze the effect of shifting cell culture parameters (P, C, T) on the in vitro as well as in vivo effort of a regulated animal m-ACI. Autologous rabbit knee articular chondrocytes were seeded within bilayer collagen I/III 3-D matrices in variation of P, C and T. Each time, 2 PCT-identical by 2 PCT-identical cell-matrix-constructs (CMC)/animal were created. Simultaneously 2 (PCT-distinct) were re-implanted (CMC-e) autologous into artificial trochlear pristine chondral defects in vivo to remain for 12 weeks while the remaining 2 were harvested (CMC-i) for immediate in vitro analysis at the time of transplantation of their identical twins. mRNA of both, CMC-e regenerates and CMC-i membranes, was analyzed for Collagen-1,-2,-10, COMP, Aggrecan, Sox9 expression by use of a mixed linear model, multiple regression analysis. Generally, CMC-i values were higher than CMC-e values for differentiation targets; the opposite was true for dedifferentiation targets. Regarding individual gene expression, in vivo regenerate cell-matrix properties were significantly dependent on initial cell-matrix in vitro values as a sign of linearity. The parameter membrane-holding time (T) had strongest effects on the resulting mRNA expression with slightly less impact of the parameter passage (P), whereas cell yield (C) had clearly less effects. Noting differences between in vitro and in vivo data, in general, optimal expression patterns concerning chondrogenic differentiation were achieved by few passages, medium cellular yield, short membrane-holding time. Clinical m-ACI may benefit from optimal orchestration of the cell culture parameters passage, yield and time., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Results of arthroscopic repair of isolated subscapularis tendon tears have not been widely studied. A detailed evaluation of subscapularis function with subscapularis strength quantification has not been performed to date., Purpose: To evaluate postoperative subscapularis muscle function and to assess the clinical outcome and structural tendon integrity with postoperative magnetic resonance imaging after arthroscopic repair of isolated subscapularis tears., Study Design: Case series; Level of evidence, 4., Methods: In a prospective study, isolated subscapularis tendon tears in 21 patients were treated with an all-arthroscopic repair. The average age of the study population was 43 years. The mean interval between trauma and surgery was 5.8 months. In 19 patients, a traumatic event caused the onset of symptoms. Subscapularis muscle function was assessed with specific clinical tests and the Constant scoring system. Postoperative subscapularis strength was evaluated with a custom-made electronic force measurement plate. All patients underwent postoperative magnetic resonance imaging to assess structural integrity of the repair., Results: The average duration of follow-up was 27 months. The Constant score increased from 50 points preoperatively to 82 points postoperatively (P < .01). Most positive preoperative lift-off and belly-press tests were reversed by surgery, with a rate of 5 (24%) persistent positive tests after surgery. In operated shoulders, subscapularis strength in the belly-press (65 vs 87 N; P < .05) and the lift-off position (44 vs 68 N; P < .05) was significantly reduced compared with the contralateral shoulder. Magnetic resonance imaging revealed an intact repair in 20 patients. Atrophy of the upper subscapularis muscle portion was present in about one-fourth of the patients and in all patients with a positive postoperative belly-press test., Conclusion: Arthroscopic repair of isolated subscapularis tendon tears achieves substantial improvement of shoulder function and a low rerupture rate. Despite excellent clinical results, a significant postoperative subscapularis strength deficit compared with the contralateral shoulder persists that can be quantified with use of the force measurement plate. Atrophy of the upper subscapularis muscle is present in 25% of the patients in the postoperative course.

Introduction: To describe indication, approach and treatment modalities for the management of knee cartilage lesions among a selected European population., Methods: An electronic questionnaire covering general and specific items concerning cartilage repair at the knee joint was designed and disposed to survey cartilage treatment characteristics among a defined population of trained and accredited musculoskeletal surgeons., Results: A total of 242 (80.13%) interviewees returned the questionnaire. Two-thirds of the respondents considered patient age to not limit (33.1%) or considered the age of 50 as the upper limit (32.2%) for interventional cartilage surgery. There was no consensus on when to correct mechanical axis deformation. Irrespective of lesion size, surgical debridement and microfracture are the techniques most frequently used. Surgical approach to full-thickness cartilage defects is commenced when the lesion size exceeds 1 cm(2) in 75.6% of respondents; mainly utilizing microfracture or debridement for defects smaller than 1, 2 and 3 cm(2). Controversy exists for treatment of lesions exceeding 3 cm(2), where autologous chondrocyte transplantation is utilized in the majority of cases (33.5%), while as well microfracture (19.0%) and with lesser frequency osteochondral plug (9.5%) transplantation are recommended. Debridement was indicated to be used in combination with other techniques, while microfracture, chondrocyte or osteochondral plug transplantation are applied as individual techniques., Conclusions: Microfracture with debridement are the two most frequently used operations in lesions up to 3 cm(2). There remains disagreement when indicating cartilage repair when age, mechanical axis deviation or treatment of lesions over 3 cm(2) are concerned.

Purpose: To evaluate single centrifuge platelet concentrate as additive for improved tendon healing. Platelet-rich plasma has been reported to improve tendon healing. Single centrifuge platelet concentration may increase platelet concentration enough to positively affect tendon healing. A single centrifuge process will lead to a blood product with increased platelet concentrations which, when added to a surgically created tendon injury, will improve tendon healing when compared with a saline control., Methods: Lewis rats had a surgical transection of the patellar tendon that was subsequently stabilized with a cerclage suture. Prior to skin closure, the tendon was saturated with either a concentrated platelet solution or saline. At 14 days, all animals were killed, and the extensor mechanism was isolated for testing. Biomechanical testing outputs included ultimate tensile load, stiffness, and energy absorbed., Results: Comparisons between the control group and the concentrated platelet group revealed no differences. A subgroup of the concentrated platelet group consisting of specimens in whom the concentration process was most successful showed significantly higher ultimate tensile load (P < 0.05) and energy absorbed to failure (P < 0.05) when compared to the control group., Conclusion: When successful, single centrifuge platelet concentration yields a solution that improves tendon healing when compared with a saline control. Single-spin platelet concentration may yield a biologically active additive that may improve tendon healing, but more studies must be undertaken to ensure that adequate platelet concentration is possible.

Topographical cartilage variation across the knee joint has been previously reported, but there is only limited information on such gene expression profiles. Articular chondrocytes from eight different topographical regions of bovine knee joints were seeded within three-dimensional scaffolds and further cultured under static conditions (unloaded control group) or subjected to an artificial joint environment within a bioreactor (loaded group). Constructs were analyzed for glycosaminoglycan (GAG), DNA, and expression of Collagen-1,-2,-10, Aggrecan, COMP, Sox9, PRG-4, PTHrp, and MMP-1,-3,-13 mRNA after 2 weeks of in vitro culture. Exclusively among loaded constructs the overall GAG production was significantly different between regions. Patella chondrocytes had overall highest, and cells from the femoral notch had overall lowest GAG/DNA under loaded conditions. Gene expression was significantly different between regions for all targets except for Sox9, PRG-4, and PTHrp among controls and with the exception of Aggrecan, Sox9, and PTHrp among loaded samples. Under mechanical stimulation Collagen-1,-2 and Aggrecan was highest at the patello-femoral joint, whereas it was lowest at typical cartilage biopsy regions. There is a clear topographical variation among distinct regions across the knee joint for gene and matrix expression profiles under static and foremost under dynamic conditions.

Purpose: The purpose of our study was to compare arthroscopic versus open measurement of cartilage defects and determination of defect grade according to the International Cartilage Repair Society (ICRS) classification., Methods: Arthroscopic determination of defect size and grade according to the ICRS classification of 450 focal cartilage defects in 407 patients who underwent autologous chondrocyte implantation was compared with definite findings at the time of open knee surgery. Results were analyzed based on defect location, defect size, and experience of the treating surgeon., Results: Open evaluation of all cartilage defects showed a mean size of 4.54 ± 2.11 cm², whereas arthroscopic determination resulted in a significantly larger mean defect size of 5.69 ± 1.81 cm² (P < .001, r = 0.757). This observation was found in all subgroups concerning defect location and experience of the treating surgeon (P < .001). Overestimation was pronounced among inexperienced surgeons (all P < .01) and in smaller defects (P < .01). Concerning grading of the defect according to the ICRS classification, there was a consensus in 80.9% of the cases when arthroscopic grading was compared with open grading. No differences were found based on defect location or experience of the treating surgeon (P > .05)., Conclusions: Although a high correlation was found between arthroscopic and open evaluation of the cartilage defect size, there is a significant overestimation of the cartilage defect size during arthroscopy. This observation is independent of defect location. Smaller defects and inexperienced surgeons are factors that make an overestimation of defect size more likely. Arthroscopic detection and estimation of the full-thickness cartilage defects according to the ICRS classification seem reliable., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Autologous chondrocyte implantation (ACI) is an accepted surgical treatment in patients with isolated cartilage defects of the knee. Age has been considered as a limiting factor and the technique has not been recommended in patients older than 40 to 50 years. Nevertheless, some more recent studies report satisfying clinical results in middle-aged patients., Hypothesis: Analogous to the microfracture technique, age over 40 years is associated with inferior clinical outcome after ACI., Study Design: Cohort study; Level of evidence, 2., Methods: Thirty-seven patients with an average age of 47.8 years (group 1) were matched with 37 patients with an average age of 31 years (group 2). Both groups underwent ACI for treatment of isolated cartilage defects of the knee. All patients were enrolled prospectively and followed for a period of 24 months using International Knee Documentation Committee (IKDC), Lysholm scale, Cincinnati sports scale, and Tegner activity evaluation instruments., Results: Statistical analysis revealed a significant increase in function after ACI in both groups as early as 6 months after surgery until the end of the study period. There was only a slight tendency for better clinical outcome in younger patients (IKDC at 24 months: group 1, 72.2 ± 15.8 [standard deviation]; group 2: 76.1 ± 14.1; P = .261; Lysholm at 24 months: group 1: 80.42 ± 15.37; group 2: 80.65 ± 12.01), no statistical significant differences were found between patients of group 1 and group 2 at any of the time points investigated., Conclusion: In contrast to other cartilage repair techniques, patients 40 years and older do not have an inferior outcome up to 24 months after ACI for isolated cartilage defects when compared with younger patients.

Autologous chondrocyte implantation (ACI) is an established therapy for the treatment of cartilage defects across the knee joint. Even though different techniques for initial biopsy have been described, the exact location, depth, and volume of the biopsy are chosen individually by the treating surgeon. This study evaluated 252 consecutive cartilage biopsies taken from the intercondylar notch with a standardized hollow cylinder system for the isolation and in vitro cultivation of human chondrocytes assigned to ACI. All biopsies were assessed for weight of total cartilage obtained, cartilage biopsy weight per cylinder, biopsy cylinder quality, and initial cell count after digestive cellular isolation as well as cell vitality. Parameters were correlated with individual patient parameters. Mean patient age was 35.1 years (median 35.9; range 14.7-56.4). Adequate amounts of cartilage assigned to chondrocyte in vitro cultivation could be harvested in all cases. The mean overall biopsy weight averaged 75.5 mg (SD +/- 44.9) and could be identified as main factor for initial cell number (mean 1.05E+05; SD +/- 7.44E+04). No correlation was found between the initial cell count and patient age (correlation coefficient r = 0.005) or grade of joint degeneration (r = 0.040). Concerning cell viability, a total of 4.4% (SD + 3.0) of the chondrocytes harvested were apoptotic. Cartilage biopsies from the intercondylar notch using a standardized hollow cylinder system provides a reliable, safe, and successful method to obtain articular cartilage for further in vitro cultivation of articular chondrocytes to achieve autologous chondrocyte transplantation.

Purpose: We report the 2-year clinical results and identify prognostic factors in patients treated with autologous chondrocyte transplantation by use of a collagen membrane to seed the chondrocytes (ACT-CS)., Methods: This is a prospective study of 59 patients who were treated with ACT-CS and followed up for 24 months. Clinical function was assessed by International Knee Documentation Committee (IKDC-2000), objective International Cartilage Repair Society, and Lysholm scores before surgery and at 6, 12, and 24 months after surgery., Results: On the basis of objective International Cartilage Repair Society (ICRS) rating, the percentage of patients rated A (normal) and B (nearly normal) increased from 33.9% preoperatively to 92.5% at 24 months after ACT-CS. IKDC and Lysholm scores increased from 50.1 points (SD, 13.4) and 60.5 points (SD, 9.4), respectively, to 76.1 points (SD, 15.2) (P < .001) and 82.5 points (SD, 13.7) (P < .001), respectively, at 24 months. The failure rate was highest, at 26.7% at 2 years' follow-up, in the subgroup of patients who underwent ACT-CS as a salvage procedure. The rate of failures in patients with isolated cartilage defects was 5.9%., Conclusions: ACT-CS represents a technical modification of membrane-associated autologous chondrocyte transplantation that combines easy handling and attractive application properties with reliable clinical results 24 months after surgery, especially in patients with isolated cartilage defects. Even though the failure rate was higher in patients with kissing lesions or mild osteoarthritis, ACT-CS also seems to improve function in a large proportion of such patients., Level of Evidence: Level IV, prospective case series., (2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: To achieve reduction of an acute acromioclavicular (AC) joint separation, novel procedures aim to provide stability and function by restoring the coracoclavicular anatomy., Hypothesis: Anatomical reconstruction for acute AC joint disruption using 2 flip-button devices results in satisfactory clinical function and provides a stable fixation., Study Design: Case series; Level of evidence, 4., Methods: The outcome of 23 consecutive patients (21 men, 2 women; mean age, 37.5 +/- 10.2 years; range, 21-59 years) who underwent anatomical reduction for an acute AC joint dislocation using 2 flip-button devices, each separately replacing 1 coracoclavicular ligament, was evaluated clinically and radiographically preoperatively and 6, 12, and 24 months postoperatively. The evaluation included a visual analog scale for pain, the Constant score, the simple shoulder test, and the Short Form-36. An additional 7 patients had similar surgery during the same period, but 4 were lost to follow-up, 2 required surgical revision, and 1 developed postoperative infection., Results: There were 3 Rockwood type III, 3 type IV, and 17 type V separations. Mean follow-up was 30.6 +/- 5.4 months (range, 24-40 months). The visual analog scale and Constant score showed significant improvements from preoperative 4.5 +/- 1.9 (range, 1-7) and 34.3 +/- 6.9 (range, 22-44) to postoperative 0.25 +/- 0.5 (range, 0-1) and 94.3 +/- 3.2 (range, 88-98) at 24 months, respectively. Postoperative radiographic AC joint alignment was unsatisfactory in 8 cases, either in the coronal, axillary, or both planes, with no different clinical outcome when compared with the remaining patients., Conclusion: Immediate anatomical reduction of an acute AC separation with flip-button devices provides satisfactory clinical results at intermediate-term follow-up. This technique should be performed by an experienced arthroscopist; tunnel and button placement are of utmost importance to avoid postoperative failure or loss of reduction.

Introduction: A dysplastic trochlea. may be missed on conventional roentgenography due to superimposition effects of the distal femoral groove., Methods: Measurements of (1) the sulcus angle, (2) the lateral trochlear slope angle and (3) the lateral to medial trochlear ratio were compared between plain axial radiographs and axial magnetic resonance images (MRI) in 24 patients suffering from clinical patellofemoral instability. Trochlear dysplasia was classified into type A through D on MR images., Results: Measurements for (1) were significantly different among all dysplasia types. It was 135.6 degrees +/- 19.8 degrees on X-ray while it was above 180 degrees on MRI within dysplasia type D patients. Measurements for (2) were different among all dysplasia types, reaching statistical significance in type B dysplasia patients. Differences between radiographs and MRI for (3) were not significant, while only on MRI the ratio increased with increasing degree of dysplasia., Conclusion: The investigation illustrates that plain axial radiographs do not represent the natural bony trochlear morphology and may mislead further clinical management.

Objective: Both, matrix-assisted chondrocyte transplantation (MACT) and osteochondral autograft transplantation (OCT), are applied for treatment of articular cartilage defects. While previous clinical studies have compared the respective outcome, there is no such information investigating the ultrastructural composition using T2 mapping comparing cartilage T2 values of the repair tissue (RT)., Methods: Eighteen patients that underwent MACT or OCT for treatment of cartilage defects at the knee joint (nine MACT, nine OCT) were matched for gender (one female, eight male pairs), age (33.8), body mass index (BMI) (28.3), defect localization, and postoperative interval (41.6 months). T2 assessment was accomplished by T2 maps, while the clinical evaluation included the Lysholm and Cincinnati knee scores, a visual analogue scale (VAS) for pain, the Tegner activity scale, and the Short Form-36., Results: Global T2 values of healthy femoral cartilage (HC) were similar among groups, while T2 values of the RT following MACT (46.8ms, SD 8.6) were significantly lower when compared to RT T2 values after OCT (55.5ms, SD 6.7) (P=0.048). MACT values were also significantly lower in comparison to HC (52.5ms, SD 7.9) within MACT patients (P=0.046), while OCT values were significantly higher compared to HC (49.9ms, SD 5.1) within OCT patients (P=0.041). The clinical outcome following MACT was consistently superior to that after OCT while only the Lysholm score reached the level of significance (MACT 77.0, OCT 66.8; P=0.04)., Conclusion: These findings indicate that MACT and OCT result in a different ultrastructural outcome, which is only partially represented by the clinical picture.

Chondrocytes represent the most important cell source for engineering of cartilaginous tissues. Depending on the tissue type and the localization within the tissue, these cells may behave differently. Numerous studies have been done to compare articular, nasal, auricular, and costal chondrocytes in order to evaluate differences between knee and ankle joint cartilage and to investigate topographical variations within an articular joint. Moreover, the zonal structure of articular cartilage needs to be considered because it leads to phenotypical differences between chondrocytes of the superficial and the deeper zones. Several studies indicate, however, that even differentiated chondrocytes demonstrate a certain plasticity and strive to adapt their phenotypes to a new mechanical and biochemical environment. The aim of this review is to report on similarities and differences of chondrocytes from different tissues, zones, and topographical locations. In particular, an overview of recent results from comparative studies is presented, and possible consequences for the design of tissue engineering models are discussed.

Mechanical and chemical stimulation have been shown to enhance in vitro chondrogenesis. The aim of this study was to analyze and compare combined physicobiochemical effects. Bovine articular chondrocytes were retrovirally transduced to express bone morphogenetic protein-2 (BMP-2) or left as naïve controls. Cells were seeded in three-dimensional polyurethane scaffolds and further cultured under static conditions or exposed to dynamic compression and shear in a joint-specific bioreactor. Four groups: control (A), load (B), BMP-2-infected (C), and BMP-2-infected plus load (D) were analyzed for DNA and glycosaminoglycan (GAG) content; collagen I, II, and X; aggrecan, (cartilage oligomeric protein (COMP), superficial zone protein, matrix metalloproteinase (MMP)-3; MMP-13 mRNA; histology; and immunohistochemistry at 7, 21, and 35 days post-seeding. Synergistic effects (D) were higher than the sum of the individual treatments (B and C) for GAG/DNA, collagen II, and COMP. Histology revealed a functional organization in D including an intense safranin O staining in C and D superior to that in A and B. Immunostaining for collagen II and aggrecan was detected in C and D and was strongest in D. The results show that both stimuli augment in vitro chondrogenesis better than in controls. Biochemical manipulation proved to be predominantly more effective than load, and synergistic effects were demonstrated.

Growth factors like BMP2 have been tested for osteochondral repair, but transfer methods used until now were insufficient. Therefore, the aim of this study was to analyse if stable BMP2 expression after retroviral vector (Bullet) transduction is able to regenerate osteochondral defects in rabbits. Fibrin clots colonized by control or BMP2-transduced chondrocytes were generated for in vitro experiments and implantation into standardized corresponding osteochondral defects (n=32) in the rabbit trochlea. After 4 and 12 weeks repair tissue was analysed by histology (HE, alcian-blue, toluidine-blue), immunohistochemistry (Col1, Col2, aggrecan, aggrecan-link protein), ELISA (BMP2), and quantitative RT-PCR (BMP2, Col1, Col2, Col10, Cbfa1, Sox9). In vitro clots were also analysed by BMP2-ELISA, histology (alcian-blue), quantitative RT-PCR and in addition by electron microscopy. BMP2 increased Col2 expression, proteoglycan production and cell size in vitro. BMP2 transduction by Bullet was efficient and gene expression was stable in vivo over at least 12 weeks. Proteoglycan content and ICRS-score of repair tissue were improved by BMP2 after 4 and 12 weeks and Col2 expression after 4 weeks compared to controls. However, in spite of stable BMP2 expression, a complete repair of osteochondral defects could not be demonstrated. Therefore, BMP2 is not suitable to regenerate osteochondral lesions completely.

Introduction: There is paucity of information available concerning the role of patellar height in unicompartmental knee arthroplasty (UKA). The present study was conducted to determine the patellar height before and after UKA and to assess possible effects on the early clinical outcome., Materials and Methods: We measured the patellar height before and after UKA in 83 consecutive knees using the Blackburne-Peel (BP) index and Insall-Salvati (IS) ratio and investigated the impact of the patellar height on the clinical outcome 2 years after surgery., Results: BP values significantly decreased from 0.81 before surgery to 0.76 postoperatively (P < 0.001). IS ratios did not significantly decrease from 1.02 to 1.01 (P = 0.108). Lower preoperative BP values were negatively correlated with the postoperative knee extension (r = -0.357, P = 0.026), while higher preoperative BP values were negatively associated with the postoperative Knee Society Score (r = -0.302, P = 0.046). Lower preoperative IS values were negatively correlated with postoperative Knee Scores (r = -0.394, P = 0.019)., Conclusion: After UKA, the patellar height decreased significantly according to the BP index, but not significantly according to the IS ratio. We found only weak and inconsistent correlations between the patellar height and clinical outcome parameters. Hence, based on the present results, the patellar height seems not to be a strict separate patient-selection criterion for UKA.

Introduction: Unicompartmental knee arthroplasty (UKA) has gained in popularity during the last years. However, the body mass index (BMI) of patients undergoing UKA is controversially discussed in the literature. There is, moreover, a paucity of information available concerning the association of BMI with early clinical outcomes after UKA., Materials and Methods: We retrospectively reviewed the clinical data of 83 consecutive UKA, 2 years after surgery, and investigated the potential association of BMI and the outcome variables Knee Society Score (KSS), University of California at Los Angeles (UCLA) activity levels, anterior knee pain (AKP), range of motion, and implant failure., Results: The KSS and UCLA significantly increased from 132 and 4.7 preoperatively to 187.5 and 7.1, respectively, after surgery. Knee flexion significantly improved from 123.7 to 128.4 degrees and the prevalence of extension deficiencies significantly decreased from 28.9 to 15.7%. Three knees (3.6%) failed and were converted to total knee arthroplasty. Failures were not associated with increased BMI (P = 0.387). The BMI had no significant association with KSS values, UCLA levels, and implant failure. We found a weak negative correlation between BMI and postoperative knee flexion (r = -0.285, P = 0.009) and a moderate positive correlation between BMI and the intensity of AKP (r = 0.525, P < 0.001)., Conclusion: The results of the present study suggest that the BMI of patients undergoing UKA has no major impact on the early clinical outcome 2 years after surgery. There was, however, a definite correlation between the BMI and AKP. Longer follow-up is necessary to determine if overweight and obesity may increase revision rates after UKA.

We present a technique for double-bundle anterior cruciate ligament (ACL) reconstruction in a 14-year-old female athlete. The patient presented with anterolateral knee rotatory instability following a traumatic injury suffered while practicing judo. The clinical examination revealed positive Lachman and pivot shift tests with no accompanying meniscal pathology. Roentgenograms revealed open physes, and magnetic resonance imaging scans confirmed an isolated midsubstance ACL tear without cartilaginous injury. The decision was made to anatomically reconstruct the ACL because the athlete wished to continue competitive judo. Autologous hamstring tendons were harvested for double-bundle ACL repair. Following arthroscopic retrograde femoral and antegrade tibial tunnel placement, the ligaments were secured using interference screws within the femoral and tibial epiphysis. Postoperative Lachman and pivot shift tests were negative.

Background: Isolated varus osteoarthritis of the knee is a common problem in patients engaged in sports and recreational activities., Hypothesis: Patients will be able to resume sporting activity after high tibial osteotomy., Study Design: Case series; Level of evidence, 4., Methods: A total of 65 patients were surveyed by postal questionnaires to determine their sporting and recreational activities at an average of 36 +/- 8.1 months (range, 14-84) after high tibial osteotomy for the treatment of medial compartment knee osteoarthritis. The clinical evaluation included the Lysholm score, the Tegner activity scale, the Activity Rating Scale, and a visual analog scale for pain., Results: At the time of survey, 90.9% of patients were engaged in sports and recreational activities, compared with 87.9% before surgery (P = .182). The number of different sporting activities declined from 3.5 preoperatively to 3.0 after surgery (P = .178). The sports frequency per week (2.1 sessions) and the activity duration per week (4.1 hours) did not significantly change from preoperative to postoperative (2.3, P = .211; and 4.2 hours, P = .709, respectively). The Lysholm score (42.4) and the visual analog scale (6.9) illustrated significant improvements (69.6, P = .001; and 2.9, P < .001, respectively). No patient returned to competitive sports after surgery, and declines were noted in the Tegner (4.9 +/- 2.3 to 4.3 +/- 1.5, P < .05) and Activity Rating Scale (5.7 +/- 5.2 to 3.3 +/- 4.6, P = .001) scores. After surgery, many patients continued to engage in high-level activities such as downhill skiing or mountain biking., Conclusion: High tibial osteotomy for the treatment of medial compartment knee osteoarthritis in the active patient demonstrated favorable clinical results and allowed patients to return to sports and recreational activities similar to the preoperative level.

Background: Traumatic acromioclavicular (AC) joint dislocations are common injuries among the active population. The injury mechanism requires excessive force delivered by a fall or blow to the shoulder. Associated injuries may occur and remain undetected if they are masked by the painful and prominent AC joint injury., Hypothesis: Intra-articular injuries associated with high-grade AC joint dislocations are common., Study Design: Case series; Level of evidence, 4., Methods: Between 2002 and 2007, 77 patients (68 male, 9 female; average age, 35.5 years; range, 17-62 years) were surgically treated for acute AC joint dislocations (Rockwood type III, 5; type IV, 30; and type V, 42). All patients underwent diagnostic glenohumeral joint arthroscopy. Concomitant intra-articular injuries were identified and treated., Results: Intra-articular injuries were found in 14 of 77 patients (18.2%). Superior labral anterior posterior (SLAP) lesions were observed in 11 of 77 patients 14.3% (SLAP I, 3; II, 2; III, 3; and IV, 3). Nineteen percent of Rockwood V lesions had associated SLAP lesions (SLAP I excluded), whereas only 3.4% of Rockwood IV lesions showed SLAP lesions. A complete supraspinatus tear was detected in 1 case, and partial articular-sided supraspinatus tears were detected in 2 cases. Four patients sustained an accompanying fracture., Conclusion: Concomitant injuries to the shoulder girdle obtained during traumatic AC joint separation may be more frequent than previously thought. Clinical diagnosis may be difficult in the setting of an acute and painful dislocated AC joint. Shoulder arthroscopy during arthroscopic AC joint stabilization may aid in detecting associated injuries.

Traditional techniques for restoration of a separated acromioclavicular joint are afflicted with various complications and often lead to recurrent dislocation. Lately, anatomic as well as minimally-invasive repair techniques with major focus on restoration of the coracoclavicular ligaments have been described for acromioclavicular joint reconstruction. We present a technique for an arthroscopically-assisted anatomical acromioclavicular joint reconstruction by replacing the conoid and trapezoid separately with nonabsorbable sutures and titanium buttons.

Introduction: Clindamycin is an antibiotic frequently used in different local application forms for the treatment of prosthetic joint infections, chronic osteomyelitis or as infection prophylaxis in bone cement. No information is available regarding its direct effects on bone cells, although very high local effective antibiotic concentrations can be achieved., Materials and Methods: We cultured pooled osteoblasts, previously derived from human trabecular bone specimens of four healthy donors, with different concentrations of clindamycin (0-500 microg/ml) for 24, 48 and 72 h. Cell proliferation (MTT), cytotoxicity [lactate dehydrogenase (LDH)-activity], cell metabolism [alkaline phosphatase (ALP)-activity] and extracellular matrix calcification (Alizarin staining) were assessed after antibiotic treatment., Results: Proliferation significantly decreased in a dose-dependent manner and reached 3.5% of control samples at 500 microg/ml at 72 h. LDH-activity was unaffected at lower concentrations but significantly increased at 500 microg/ml at 48 and 72 h. ALP-activity significantly increased at 10 microg/ml at 24 and 48 h and then decreased in a time- and dose-dependent manner. Calcification increased at 10 and 25 microg/ml, while it decreased or no calcification was found at concentrations of 50 microg/ml and above., Conclusion: We could demonstrate that clindamycin at lower concentrations stimulated the cell metabolism of human osteoblasts and that higher clindamycin levels of 500 microg/ml had cytotoxic effects. The observed effects of high clindamycin levels on human osteoblasts highlight a potential alteration of bone metabolism in vivo and have to be taken into account in local antibiotic administration, e.g., in clindamycin-impregnated bone cement, where such high antibiotic concentrations can be achieved.

Knowledge of rotator cuff tears, especially in young people, and their cause has been vastly expanded in recent years. This is reflected in the understanding of the pathogenesis of these lesions and the specific therapy. In contrast to the mostly degenerative tears in older people, the causes in young, active people differ: traumatic disruption, internal impingement due to instability (PSI, ASI), SLAP lesion, and microtraumatic causes may be found. Recently, connections between the different pathologies like internal impingement and the SLAP lesion were shown. For an accurate diagnosis and differentiation between the different pathologies an exact clinical examination and a high-quality MRI scan with intra-articular contrast enhancer is necessary. The final therapy should be planned based on the causative pathology; then good long-term results will be achieved and return to sports is likely. If there is no structural damage, conservative therapy should be initiated. If there is any structural damage, e.g., SLAP lesion or rotator cuff tear, surgical treatment is indicated. Besides a SLAP repair and rotator cuff suturing, care must be given not to miss an accompanying instability. These instabilities should also be corrected, e.g., with arthroscopic ventral capsular plication, otherwise results are worse.

The local application of antibiotics in bone cement achieves high local effective antibiotic concentrations. Cefuroxime is widely used for antibiotic prophylaxis in orthopedic surgery, and several reports highlighted a beneficial outcome if cefuroxime-impregnated bone cement was used, but there is a lack of information of direct cefuroxime effects on human bone cells. We, therefore, cultured osteoblasts, previously derived from human trabecular bone specimens and used as a cell-pool further on, with different concentrations of cefuroxime (0-1000 microg/mL) for 24, 48, or 72 h. For reversibility testing, osteoblasts were cultivated for 24 h with cefuroxime followed by 48 h without antibiotics. Cell proliferation (MTT), cytotoxicity (lactate dehydrogenase (LDH)-activity), cell metabolism (alkaline phosphatase (ALP)-activity), and extracellular matrix calcification (Alizarin staining) were assessed after antibiotic treatment. Cefuroxime concentrations of 25-100 microg/mL had little or no effect on cellular proliferation. Proliferation was significantly stimulated at 250 and 1000 microg/mL at each time. LDH-activity significantly increased at the highest concentration of 1000 microg/mL at 72 h. ALP-activity first increased at lower concentrations and then significantly decreased at 1000 microg/mL at 48 and 72 h. Similar to ALP-activity, calcification increased at lower concentrations and was not detectable at 1000 microg/mL. All revealed effects at 24 h were at least partially reversible. In the present study, we demonstrated that cefuroxime at lower concentrations had no inhibiting effects on human osteoblasts. In contrast, higher concentrations significantly altered osteoblastic function. When administered locally in total joint arthroplasty, for example, in antibiotic-impregnated bone cement, cefuroxime might critically impair osteoblastic function and periprosthetic bone metabolism.

A tight stricture in the lower esophageal stricture in a child poses significant surgical challenges. We report the first case of a laparoscopically assisted resection of a distal esophageal stricture in a 2-year-old girl with clinical AIDS (CDC stage 3). The patient presented with dysphagia, vomiting, and progressive weight loss. A barium swallow confirmed a distal tight esophageal stricture in the lower esophagus. After the second dilatation attempt failed a gastrostomy was inserted and highly active antiretroviral therapy treatment commenced. Follow-up contrast studies showed a nearly complete obstruction of the distal esophagus. A laparoscopically assisted resection of the esophageal stricture with a primary stapled anastomosis was performed with good results. At follow-up 8 months postoperative the child was tolerating feeds well and thriving.

Objective: The repair of osteochondral defects with chondrocytes genetically modified to express desired growth factors promises great potential in orthopaedic therapy. Controlled expression of the transgenes is required in many instances. The objective of the present study was to demonstrate the inducibility of tetracycline-responsive transgene expression in osteochondral defects in the knee joint filled with genetically modified chondrocyte implants., Methods: An expression plasmid containing the lacZ gene under the control of the minimal CMV promoter fused to the Tet-responsible element (TRE) as well as the reverse transactivator (rtTA2s-M2) was constructed and used to transfect isolated articular chondrocytes from New Zealand white rabbits. rtTA2s-M2 binds to the TRE in the presence of tetracycline and leads to the transcription of the transgene. Different concentrations of DNA and various DNA:lipid ratios were tested to determine best transfection conditions. Transfection efficiency and inducibility were analysed by histochemical analysis and flow-cytometry. To evaluate the system in vivo, collagen-sponges were seeded with transfected autologous chondrocytes and implanted in osteochondral defects in the knees of NZW-rabbits. Gene expression was induced by doxycycline and 3 weeks later, LacZ-expression in isolated knee joints was evaluated in histological sections by X-gal staining., Results: In vitro 13.5% (+/-1.32) of induced primary chondrocytes were LacZ-positive, while non-induced controls showed a background-staining in 0.6% (+/-0.2). In vivo, upon doxycycline treatment, induction of lacZ-gene-expression could be demonstrated in chondrocytes in 3-week-old, well-integrated implants., Conclusion: For the first time, tetracycline-inducible gene expression is demonstrated to work in the treatment of osteochondral defects. This demonstrates the feasibility for a gene therapy-assisted approach using controlled expression of therapeutic growth factors from transplanted genetically modified chondrocytes.