Significantly worse isokinetic hamstring-quadriceps ratio in patellofemoral compared to condylar defects 4 years after autologous chondrocyte implantation.

PURPOSE: Detailed biomechanical analysis including isokinetic muscle strength measurements after autologous chondrocyte implantation (ACI) are still rare, but might be of crucial importance for long-term outcomes. The present prospective study was performed to evaluate whether defect location had any influence on clinical and biomechanical outcomes 4 years after ACI. METHODS: Forty-four patients with full-thickness cartilage defects ICRS grade III B and C underwent ACI and were assigned to two groups, the femoral condyle group or the patellofemoral joint group. Clinical scores were gathered preoperatively and 6, 12 and 48 months after implantation using the International Knee Documentation Committee (IKDC) score and the International Cartilage Repair Society (ICRS) form. Isokinetic strength measurements were performed 48 months postoperatively comparing healthy and operated knee joint of each patient. RESULTS: Clinical scores (ICRS, IKDC) showed continuous significant (p < 0.05) improvement over the study period for both groups. Isokinetic muscle strength measurements showed significantly reduced maximum strength capacities for the operated knee joint compared to the healthy knee in both groups (p < 0.05). Hamstring-quadriceps ratios of the operated extremity revealed a significant change in physiological muscle balancing (ratios >1.0) based on significantly impaired extensor muscle strength in the patellofemoral joint group. CONCLUSION: All patients showed significant strength deficits on the operated extremity 4 years after ACI. Furthermore, the patellofemoral compartment in particular showed significantly worse hamstring-quadriceps ratios compared to condylar defects. Consequently, more efforts should be made to restore muscular strength especially of the quadriceps and the rehabilitation protocol should be adjusted accordingly. LEVEL OF EVIDENCE: II.

Is gender influencing the biomechanical results after autologous chondrocyte implantation?

PURPOSE: The influence of gender on the biomechanical outcome after autologous chondrocyte implantation (ACI) including isokinetic muscle strength measurements has not been investigated. The present prospective study was performed to evaluate gender-specific differences in the biomechanical function 48 months after ACI. METHODS: Fifty-two patients (mean age 35.6 ± 8.5 years) that met our inclusion criteria, underwent ACI with Bioseed C(®) and were evaluated with the KOOS score preoperatively, 6, 12 and 48 months after surgery. At final follow-up, 44 out of the 52 patients underwent biomechanical evaluation with isokinetic strength measurements of both knees. All data were evaluated separately for men and women and compared for each time interval using the Mann-Whitney U test. RESULTS: Clinical scores improved significantly over the whole study period (p < 0.05). Male patients demonstrated significantly better scores during the follow-up in the KOOS score (p < 0.05). Isokinetic strength measurements after 48 months revealed a significant strength deficit of the treated knee in all test modes compared to the healthy extremity (p < 0.05). Furthermore, male patients achieved significantly higher strength values compared to female patients (p < 0.05). CONCLUSIONS: ACI is a viable treatment option for full-thickness chondral defects in the knee of both genders. Isokinetic muscle strength measures are significantly worse in women (p < 0.05), but physiological and may play a role for the explanation of gender-specific results after ACI.

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.

Arthroscopic anatomy, variants, and pathologic findings in shoulder instability.

Shoulder instability is a common diagnosis that often requires surgical treatment. A detailed knowledge of the shoulder anatomy and its stabilizing structures is of utmost importance for successful treatment of shoulder instabilities. Identifying anatomic variants (e.g., sublabral hole, meniscoid labrum, cordlike middle glenohumeral ligament, and Buford complex) and distinguishing them from pathologic findings may be especially difficult, as shown by the high interobserver variability. Over the last decade, basic research and arthroscopic surgery have improved our understanding of the shoulder anatomy and pathology. In the context of shoulder instability, injuries of the glenoid (bony Bankart), injuries of the glenoid labrum superiorly (SLAP) or anteroinferiorly (e.g., Bankart, anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), accompanying cartilage lesions (Hill-Sachs, glenolabral articular disruption), and rotator interval and pulley lesions, as well as signs of dynamic instability impingement (posterior-superior impingement, anterior-superior impingement) can be exactly diagnosed (magnetic resonance imaging with intra-articular gadolinium, arthroscopy) and treated (arthroscopy). Therefore the purpose of this article is to review the current literature concerning shoulder anatomy/pathology related to shoulder stability/instability to improve clinical diagnosis and surgical treatment of our patients.

Chondrocyte-seeded type I/III collagen membrane for autologous chondrocyte transplantation: prospective 2-year results in patients with cartilage defects of the knee joint.

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.

Standardized cartilage biopsies from the intercondylar notch for autologous chondrocyte implantation (ACI).

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.

Autologous chondrocyte implantation versus ACI using 3D-bioresorbable graft for the treatment of large full-thickness cartilage lesions of the knee.

BACKGROUND: In autologous chondrocyte implantation (ACI), the periosteum patch which is sutured over the cartilage defect has been identified as a major source of complications such as periosteal hypertrophy. In the present retrospective study, we compared midterm results of first-generation ACI with a periosteal patch to second generation ACI using a biodegradable collagen fleece (BioSeed-C) in 82 patients suffering from chronic posttraumatic and degenerative cartilage lesions of the knee. METHODS: Clinical outcome was assessed in 42 patients of group 1 and in 40 patients of group 2 before implantation of the autologous chondrocytes and at a minimum follow-up of 2 years using the ICRS score, the modified Cincinnati score and the Lysholm score. RESULTS: Although patients treated with BioSeed-C had more previous surgical procedures on their respective knees, highly significant improvements (P < 0.001) were assessed in both groups at comparable outcome levels: the ICRS score improved from grade D (poor) preoperatively to grade C (fair); the modified Cincinnati knee score from 3.26 to 6.4 (group 1) and 3.3 and 6.88 (group 2). Lysholm score improved from 33 to 70 points (group 1) and from 47 to 78 points (group 2), respectively. Revision surgery was due to symptomatic periosteal hypertrophy (n = 4), graft failure (n = 3), plica syndrome (n = 2) synovectomy (n = 1) (group 1); and graft failure (n = 2), debridement (n = 1), synovectomy (n = 2) (group 2). CONCLUSION: These results suggest that BioSeed-C is an equally effective treatment option for focal degenerative chondral lesions of the knee in this challenging and complex patient profile.

Two-year results of open-wedge high tibial osteotomy with fixation by medial plate fixator for medial compartment arthritis with varus malalignment of the knee.

PURPOSE: The purpose of our study was to evaluate the complications, technique-related risks, and the clinical course of patients treated with high tibial osteotomy (HTO) for medial arthritis of the knee with varus malalignment. METHODS: Forty-three of 46 consecutive patients (follow-up, 93.5%) treated with HTO using the TomoFix implant (Synthes, Solothurn, Switzerland) were followed-up for 24 months. Radiographic and clinical data were collected preoperatively as well as 6, 12, and 24 months after surgery using standard instruments (Lysholm and subjective International Knee Documentation Committee score). RESULTS: Excellent and good results were achieved in 67.5% of patients. Thirty-seven patients (86.0%) reported clinical improvement at 24 months compared to preoperative status. Evaluation of the clinical course following HTO revealed a significant increase in function after 12 (P < .01) and 24 (P < .01), but not at 6 months (P = .336) after surgery. A further increase was found between 12 and 24 months (P = .017); 67.5% of the study population returned to their predisease sports activity level at 24 months after surgery. Except for 1 case of intra-articular fracture, no severe intraoperative complications were found. One case of nonunion that demanded additional surgery was observed. CONCLUSIONS: HTO with an open-wedge technique using the TomoFix implant seems to be a safe and efficient procedure. Our data show that postoperative recovery is long, with a majority of patients not reaching a functional end-point by 6 or 12 months. In many patients, further improvement was found after 12 months, which might be related to a removal of the implant. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Autologous chondrocyte implantation for the treatment of retropatellar cartilage defects: clinical results referred to defect localisation.

INTRODUCTION: Although autologous chondrocyte implantation (ACI) has become well established for the treatment of full-thickness cartilage defects of the knee joint, nevertheless clinical results of retropatellar lesions are still inferior compared to those of defects located on femoral condyles. We report the clinical results obtained in 70 patients treated with ACI for full-thickness defects of the patella, with special reference to defect location and size, age, body mass index and sports activity. METHODS: At a follow-up of 38.4 months (range 14-64, follow-up rate 83.3%), patients' subjective functional knee scores (IKDC, Lysholm) were analysed, as were the results of objective examination (according to ICRS). RESULTS: Mean patient age at the time of surgery was 34.3 years (+/-10.1). The mean Lysholm score at the time of follow-up was 73.0 (+/-22.4) and the subjective IKDC score was 61.6 (+/-21.5); normal and nearly normal clinical results according to the objective criteria of the International Cartilage Research Society (ICRS) were achieved in 67.1% of the patients, while abnormal results were achieved in 20.0% of the patients and severely abnormal results, in 12.9%. While different surgical techniques did not seem to have any significant influence on the treatment results, both defect size and defect location within the patella were found to be significantly associated with clinical outcome. The corollaries to this are that larger cartilage lesions of the patella are associated with an inferior outcome (p = 0.007) and that cartilage defects located on the lateral patellar facet are correlated with a better clinical outcome than those located on the medial facet or those involving both facets (p = 0.017). CONCLUSION: This study demonstrates that within a group of patients treated with ACI for retropatellar cartilage lesion there are significant differences in clinical outcome, which are important and should be taken into account of when a decision has to be made on whether or not ACI is indicated.

Autologous chondrocyte implantation in chondral defects of the knee with a type I/III collagen membrane: a prospective study with a 3-year follow-up.

PURPOSE: The clinical results after autologous chondrocyte implantation (ACI) with a collagen membrane using sequential objective patient evaluation (clinical examination and magnetic resonance imaging [MRI]) are inadequately reported. This prospective study was performed to determine the results after ACI at different time intervals over a period of 36 months. METHODS: Between 2000 and 2002, 63 patients (mean age, 34 years) with full-thickness chondral lesions of the knee underwent an autologous chondrocyte implantation and were evaluated preoperatively and at 6, 18, and 36 months after surgery. The chondrocyte suspension within the defect was covered with a type I/III collagen membrane. Depending on the localization of the defects (femoral condyles, trochlea, and retropatellar), the patients were assigned to three different groups. Exclusion criteria were meniscal pathologies, axial malpositioning, and ligament instabilities. Baseline clinical scores (modified Cincinnati knee score and the International Cartilage Repair Society score) were determined and compared with follow-up data by using the paired Wilcoxon test. RESULTS: The ICRS and modified Cincinnati score showed significant improvement (P < .01) in all time intervals between preoperative and 6, 18, and 36 months after surgery. There was no significant difference in the final outcome between different defect localizations (P > .2). The Pearson coefficient of correlation between clinical and MRI scores was 0.73 and significant at the 0.01 level. There was no patient with a symptomatic graft hypertrophy. CONCLUSIONS: ACI is an effective method in the treatment of isolated cartilage defects in the knee. Graft hypertrophy can be avoided by using a collagen membrane. Significant improvement (P < .001) occurs still between 18 and 36 months after surgery. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Autologous chondrocyte implantation for the treatment of large full-thickness cartilage lesions of the knee.

OBJECTIVE: To investigate the benefit, reliability, and complication rate of autologous chondrocyte implantation (ACI) in patients with large full-thickness cartilage defects of the knee. METHODS: Between March 1997 and December 2001, 71 consecutive patients (24 women, 47 men) were treated with ACI at the Freiburg University Hospital, Germany, and were included in this study. Average age was 35 years (13-61). Lesions were mainly situated on the medial femoral condyle (n=46); mean defects size was 6.61 cm2 (2-17.5), outerbridge grade III-IV. Number of previous surgical procedures was 2.13 (0-8). For outcome measurement, International Cartilage Repair Society (ICRS) knee examination form, Lysholm score, Cincinnati knee score, and the modified Cincinnati-knee-score were used. Correlation between treatment results, and previous surgical procedures was examined. Statistical analysis was performed using the 2-tailed paired and unpaired Wilcoxon-rang-sum-test (alpha=0.05). RESULTS: Mean follow-up 36 months (24-65). Modified Cincinnati score overall rating demonstrated highly significant improvements from 3.24 to 6.44 points (patients) and from 3.35 to 6.87 (physicians). Mean Cincinnati score improved from 27-72 points, ICRS score improved from grade D to grade C, and average Lysholm score from 33 points to 69 points. All but 11 patients returned to casual sports, 25 patients went in for regular sports 1-3 times a week or more. Complication rate was 11%. CONCLUSION: Autologous chondrocyte implantation provides an appropriate method for the treatment of full-thickness cartilage lesions of the knee and gives good clinical short-term results.

Is microfracture of chondral defects in the knee associated with different results in patients aged 40 years or younger?

PURPOSE: Age-dependent studies about the clinical result after microfracture of cartilage lesions in the knee are still missing. This prospective study was performed to discover age-dependent differences in the results after microfracture over a period of 36 months. METHODS: Between 1999 and 2002, 85 patients (mean age, 39 years) with full-thickness chondral lesions underwent the microfracture procedure and were evaluated preoperatively and at 6, 18, and 36 months after surgery. Depending on the patients' age (< or =40 years or >40 years) and the localization of the defects (femoral condyles, tibia, and patellofemoral joint), the patients were assigned to 6 different groups. Exclusion criteria were meniscal pathologic conditions, tibiofemoral malalignment, and ligament instabilities. Baseline clinical scores were compared with follow-up data by use of paired Wilcoxon tests for the modified Cincinnati knee score and the International Cartilage Repair Society (ICRS) score. RESULTS: The scores improved in all groups over the whole study period (P < .05). Patients aged 40 years or younger had significantly better results (P < .01) for both scores compared with older patients. Between 18 and 36 months after microfracture, the ICRS score deteriorated significantly (P < .05) in patients aged over 40 years whereas younger patients with defects on the femoral condyles and on the tibia showed neither a significant improvement nor a significant deterioration in the ICRS score (P > .1). Magnetic resonance imaging 36 months after surgery revealed better defect filling and a better overall score in younger patients (P < .05). The Spearman coefficient of correlation between clinical and magnetic resonance imaging scores was 0.84. CONCLUSIONS: The clinical results after microfracture of full-thickness cartilage lesions in the knee are age-dependent. Deterioration begins 18 months after surgery and is significantly pronounced in patients aged older than 40 years. The best prognostic factor was found to be a patient age of 40 or younger with defects on the femoral condyles. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Isolated and combined tears of the subscapularis tendon.

BACKGROUND: Isolated and combined subscapularis tendon tears are rare and are described in the literature only in small numbers. HYPOTHESIS: The outcome of surgical intervention for isolated and combined subscapularis tendon tears may be influenced by the tear pattern of the anterior rotator cuff and the period of time between trauma and surgical procedure. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1994 and 1999, 34 shoulders with isolated traumatic tears (16 shoulders) or subscapularis tendon rupture combined with a supraspinatus tendon tear were treated operatively. The average patient age was 51 years, and the mean follow-up period was 37 months. For statistical analyses, the Friedman and Mann-Whitney tests were used. RESULTS: In patients with isolated tears, the Constant score rose from an average of 43.9 to 88.7 points (P < .01), and in patients with combined tears, it rose from an average of 40.6 to 74.7 points (P <.01). Isolated tears improved 14 points more than combined tears (P <.05). The delay between trauma and surgical intervention was inversely proportional to the improvement in the Constant score. The Spearman coefficient of correlation was -0.97 in isolated tears and -0.89 in combined tears. CONCLUSIONS: Young patients with isolated traumatic tears of the subscapularis tendon and immediate repair have the best prognostic factors for treatment. Accuracy in the trauma history and the clinical and radiographic examination is demanded.

Long-term outcomes after first-generation autologous chondrocyte implantation for cartilage defects of the knee.

BACKGROUND: Autologous chondrocyte implantation (ACI) represents an established surgical therapy for large cartilage defects of the knee joint. Although various studies report satisfying midterm results, little is known about long-term outcomes. PURPOSE: To evaluate long-term clinical and magnetic resonance imaging (MRI) outcomes after ACI. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between January 1997 and June 2001, a total of 86 patients were treated with ACI for isolated cartilage defects of the knee. The mean patient age at the time of surgery was 33.3 ± 10.2 years, and the mean defect size was 6.5 ± 4.0 cm(2). Thirty-four defects were located on the medial femoral condyle and 13 on the lateral femoral condyle, while 6 patients were treated for cartilage defects of the trochlear groove and 17 for patellar lesions. At a mean follow-up of 10.9 ± 1.1 years, 70 patients (follow-up rate, 82%) treated for 82 full-thickness cartilage defects of the knee were available for an evaluation of knee function using standard instruments, while 59 of these patients were additionally evaluated by 1.5-T MRI to quantify the magnetic resonance observation of cartilage repair tissue (MOCART) score. Clinical function at follow-up was assessed by means of the Lysholm score, the International Knee Documentation Committee (IKDC) score, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Patient activity was assessed by the Tegner score. In addition, pain on a visual analog scale (VAS) and patient satisfaction were evaluated separately. RESULTS: At follow-up, 77% reported being "satisfied" or "very satisfied." The mean IKDC score at follow-up was 74.0 ± 17.3. The mean Lysholm score improved from 42.0 ± 22.5 before surgery to 71.0 ± 17.4 at follow-up (P < .01). The mean pain score on the VAS decreased from 7.2 ± 1.9 preoperatively to 2.1 ± 2.1 postoperatively. The mean MOCART score was 44.9 ± 23.6. Defect-associated bone marrow edema was found in 78% of the cases. Nevertheless, no correlation between the MOCART score and clinical outcome (IKDC score) could be found (Pearson coefficient, r = 0.173). CONCLUSION: First-generation ACI leads to satisfying clinical results in terms of patient satisfaction, reduction of pain, and improvement in knee function. Nevertheless, full restoration of knee function cannot be achieved. Although MRI reveals lesions in the majority of the cases and the overall MOCART score seems moderate, this could not be correlated with long-term clinical outcomes.

Clinical and electromyographic results of proximal and distal realignment procedures in young patients with recurrent patellar dislocations.

BACKGROUND: Until now, no study has been published about the electromyographic changes in the extensor apparatus after the Green procedure for proximal realignment in young patients with recurrent patellar dislocations. This electromyographic study was performed to analyze imbalances between the vastus medialis and vastus lateralis muscles after different patellar realignment procedures. HYPOTHESIS: Surgical proximal realignment leads to electromyographic changes in the extensor apparatus of the knee and to imbalances between the vastus medialis and vastus lateralis muscles. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 28 knees of 25 patients, with a mean age of 15 years, were treated operatively for recurrent patellar dislocations. The mean follow-up was 6.3 years. Depending on the type of surgical intervention, the patients were assigned to 3 different groups: the patients of group 1 underwent only the Green vastus medialis obliquus (VMO) advancement, group 2 was treated with a combination of the Green proximal and the Roux-Goldthwait distal realignment, and group 3 was treated with a combination of the Green proximal realignment and an additional tubercle transfer. All patients underwent clinical, radiological, and electromyographic examinations. The muscle activities of a healthy control group without patellar dislocations were used for comparison. RESULTS: A combination of the Green procedure and tubercle transfer led to significantly better clinical results and a lower number of redislocations (P < .05) compared with patients who underwent only the Green proximal realignment. While ascending or descending stairs, the ratio between the electromyographic activities of the vastus medialis and vastus lateralis muscles in groups 1 and 2 was significantly smaller compared with the control group (P < .02). Only the electromyograms of group 3 revealed a balanced extensor apparatus during loading with comparable activities of the vastus medialis and vastus lateralis muscles and no significant difference to the control group (P = .37). CONCLUSION: Our electromyographic investigations showed the importance of the vastus medialis in the pathogenesis of malalignment of the extensor mechanism. The Green VMO advancement without tibial tubercle transfer is not able to balance the activities of the vastus medialis and vastus lateralis muscles and cannot be recommended for further use.

Influence of sex on the outcome of autologous chondrocyte implantation in chondral defects of the knee.

BACKGROUND: Sex-specific outcomes have been reported in anterior cruciate ligament reconstruction as well as in osteoarthrosis progression, but there are currently no related published data on autologous chondrocyte implantation (ACI). The present prospective study was performed to investigate sex-dependent differences in the results after ACI. HYPOTHESIS: The clinical and magnetic resonance imaging (MRI) results after ACI of the knee are influenced by the patient's sex. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The midterm clinical and MRI results of a cell-based fibrin-polymer graft for the treatment of full-thickness cartilage defects were evaluated preoperatively and 6, 12, and 48 months after surgery in 52 patients (male:female ratio, 25:27; average age, 35.6 years). Depending on the sex and the location of the defects (femoral condyles, n = 32; patellofemoral compartment, n = 20), patients were assigned to 4 different groups. Baseline clinical scores were compared with follow-up data by paired Wilcoxon tests for the Lysholm score and the International Knee Documentation Committee (IKDC) scoring system. Sex-specific differences were evaluated with the Mann-Whitney U test. The MRI evaluation was performed with the Henderson score at final follow-up. RESULTS: Clinical scores improved in all groups over the whole study period (P < .05). Compared with female patients, male patients achieved significantly better results in the Lysholm score at all time intervals and in the IKDC score at 6 and 12 months after surgery (P < .05). In a subgroup analysis, female patients with patellar defects had the worst results in both clinical scores. With the available number of patients, MRI evaluation at 48 months after surgery revealed no significant difference in defect fill between male and female patients (P > .05). The Pearson correlation coefficient between both clinical scores and the MRI parameters of defect fill and cartilage signal was significant (P < .05). CONCLUSION: Autologous chondrocyte implantation is a promising treatment option for full-thickness cartilage defects of male and female knee joints. Female patients with patellar defects have worse prognostic factors.

Biomechanical evaluation of different abduction splints for the treatment of congenital hip dysplasia.

BACKGROUND: Abduction splints for the treatment of hip dysplasia normally operate on curbing the legs at the hip flexion and abduction. The forces are absorbed in different designs of shoulder straps and thus diverted to the shoulder and the spine. The present study is the first comparing these undesired forces of two spread orthoses and subsequently the transmitted forces to the infant's spine. METHODS: Between March 2009 and October 2009 the hips of 290 infants were investigated by ultrasound within the first 3 days after birth. Thereof 20 infants with a hip dysplasia Graf type IIc, D or IIIa met our inclusion criteria and were investigated with a Tübinger and a Superior abduction splint. Biomechanical evaluation was performed by using a high-sensitive strain gauge sensor applied to the infant's orthoses between pelvic harness and shoulder straps. FINDINGS: The transmitted forces to the infant's shoulders correlated significantly with their body mass (P<0.05). Maximal forces on the shoulder of the infants and subsequently transmitted forces on the spine were significantly higher (P<0.05) with the Tübinger splint (range 7.6N to 32.3N; arithmetic mean M: 13.7N) in comparison to the Superior orthosis (range 0.0N to 3.5N; M: 0.7N). INTERPRETATION: The Superior orthosis works with primary load transmission to the pelvic bone. Using the Tübinger splint the shoulders of the newborn infants are loaded with a maximum of 93.9% of their body mass. This may influence the development of the growing infant's spine.

Karyotyping of human chondrocytes in scaffold-assisted cartilage tissue engineering.

Scaffold-assisted autologous chondrocyte implantation (ACI) is an effective clinical procedure for cartilage repair. The aim of our study was to evaluate the chromosomal stability of human chondrocytes subjected to typical cell culture procedures needed for regenerative approaches in polymer-scaffold-assisted cartilage repair. Chondrocytes derived from post mortem donors and from donors scheduled for ACI were expanded, cryopreserved and re-arranged in polyglycolic acid (PGA)-fibrin scaffolds for tissue culture. Chondrocyte redifferentiation was analyzed by electron microscopy, histology and gene expression analysis. Karyotyping was performed using GTG banding and fluorescence in situ hybridization on a single cell basis. Chondrocytes showed de- and redifferentiation accompanied by the formation of extracellular matrix and induction of typical chondrocyte marker genes like type II collagen in PGA-fibrin scaffolds. Post mortem chondrocytes showed up to 1.7% structural and high numbers of numerical (up to 26.7%) chromosomal aberrations, while chondrocytes from living donors scheduled for ACI showed up to 1.8% structural and up to 1.3% numerical alterations. Cytogenetically, cell culture procedures and PGA-fibrin scaffolds did not significantly alter chromosomal integrity of the chondrocyte genome. Human chondrocytes derived from living donors subjected to regenerative medicine cell culture procedures like cell expansion, cryopreservation and culture in resorbable polymer-based scaffolds show normal chromosomal integrity and normal karyotypes.

Autologous chondrocyte implantation (ACI) for the treatment of large and complex cartilage lesions of the knee.

BACKGROUND: Complex cartilage lesions of the knee including large cartilage defects, kissing lesions, and osteoarthritis (OA) represent a common problem in orthopaedic surgery and a challenging task for the orthopaedic surgeon. As there is only limited data, we performed a prospective clinical study to investigate the benefit of autologous chondrocyte implantation (ACI) for this demanding patient population. METHODS: Fifty-one patients displaying at least one of the criteria were included in the present retrospective study: (1.) defect size larger than 10 cm2; (2.) multiple lesions; (3.) kissing lesions, cartilage lesions Outerbridge grade III-IV, and/or (4.) mild/moderate osteoarthritis (OA). For outcome measurements, the International Cartilage Society's International Knee Documentation Committee's (IKDC) questionnaire, as well as the Cincinnati, Tegner, Lysholm and Noyes scores were used. Radiographic evaluation for OA was done using the Kellgren score. RESULTS AND DISCUSSION: Patient's age was 36 years (13-61), defects size 7.25 (3-17.5) cm2, previous surgical procedures 1.94 (0-8), and follow-up 30 (12-63) months. Instruments for outcome measurement indicated significant improvement in activity, working ability, and sports. Mean ICRS grade improved from 3.8 preoperatively to grade 3 postoperatively, Tegner grade 1.4 enhanced to grade 3.39. The Cincinnati score enhanced from 25.65 to 66.33, the Lysholm score from 33.26 to 64.68, the Larson score from 43.59 to 79.31, and Noyes score from 12.5 to 46.67, representing an improvement from Cincinnati grade 3.65 to grade 2.1. Lysholm grade 4 improved to grade 3.33, and Larson grade 3.96 to 2.78 (Table 1), (p < 0.001). Patients with kissing cartilage lesions had similar results as patients with single cartilage lesions. CONCLUSION: Our results suggest that ACI provides mid-term results in patients with complex cartilage lesions of the knee. If long term results will confirm our findings, ACI may be a considered as a valuable tool for the treatment of complex cartilage lesions of the knee.