[Functional outcomes and return to sports, work, and daily activities after revision UKA compared to primary UKA and TKA]. / Funktionelle Ergebnisse und Wiederaufnahme von Sport, Arbeit und Alltagsaktivitäten nach Revision eines Monoschlittens im Vergleich zur Primärimplantation eines Mono- und Doppelschlittens.

BACKGROUND: Unicompartmental knee arthroplasty (UKA), in addition to total knee arthroplasty (TKA), has been shown to be effective in the surgical treatment of knee osteoarthritis with appropriate patient selection. In clinical studies, it has demonstrated superior functional results with lower complication rates. In clinical practice, these advantages must be weighed against the disadvantage of an increased revision rate, especially in younger patients with sports and work activities. OBJECTIVES: The aim of this study was to compare the functional outcome as well as the time to return to daily activities, work, and sports after revision of UKA to TKA with those of primary UKA and primary TKA using a matched-pair analysis. MATERIALS AND METHODS: The study was based on a matched-pair analysis at two defined time points, always comparing 28 patients who underwent either revision of a UKA to a TKA, primary UKA, or primary TKA. Patients completed the Oxford Knee Score, UCLA score, Knee Society score, and WOMAC score during standardized follow-up. In addition, postoperative patient satisfaction and return to activities of daily living, work, and sports were recorded in a standardized manner, and a clinical examination was performed. RESULTS: The four functional scores studied showed a common trend in favor of UKA, followed by primary TKA and revision TKA. The differences between converted UKA and primary TKA were not significant. However, at 3.2 years after the last surgery, the results of the converted UKA were significantly lower than those of the primary UKA. Return to work and sports tended to occur the earliest after UKA, followed by TKA and the revision group. All groups showed a tendency to engage in low-impact sports. CONCLUSION: The functional results of revised UKA were significantly inferior to those of primary UKA based on a 3-year follow-up. Return to work, sports, and activities of daily living tended to take longer after revision than after primary implantation of either a UKA or a TKA.

Empfehlungen der AG Klinische Geweberegeneration zur Behandlung von Knorpelschäden am Kniegelenk. / Empfehlungen der AG Klinische Geweberegeneration zur Behandlung von Knorpelschäden am Kniegelenk.

The Working Group of the German Orthopedic and Trauma Society (DGOU) on Tissue Regeneration has published recommendations on the indication of different surgical approaches for treatment of full-thickness cartilage defects in the knee joint in 2004, 2013 and 2016. Based upon new scientific knowledge and new developments, this recommendation is an update based upon the best clinical evidence available. In addition to prospective randomised controlled clinical trials, this also includes studies with a lower level of evidence. In the absence of evidence, the decision is based on a consensus process within the members of the working group.The principle of making decision dependent on defect size has not been changed in the new recommendation either. The indication for arthroscopic microfracturing has been reduced up to a defect size of 2 cm2 maximum, while autologous chondrocyte implantation is the method of choice for larger cartilage defects. Additionally, matrix-augmented bone marrow stimulation (mBMS) has been included in the recommendation for defects ranging from 1 to 4.5 cm2. For the treatment of smaller osteochondral defects, in addition to osteochondral transplantation (OCT), mBMS is also recommended. For larger defects, matrix-augmented autologous chondrocyte implantation (mACI/mACT) in combination with augmentation of the subchondral bone is recommended.

Effect of shape and size of supraspinatus tears on rotator cuff strain distribution: an in vitro study.

BACKGROUND: The impact of the size and shape of a supraspinatus tear on the strain of the intact rotator cuff and the kinematics of the shoulder is still unknown. This, however, can be relevant when deciding whether surgical reconstruction is required to prevent an increase in a tendon defect. In this study, the effect of tear width and shape on rotator cuff strain and glenohumeral kinematics was evaluated during active abduction. METHODS: Twelve fresh-frozen cadaveric shoulders with intact rotator cuffs were used in this study. We created 50% and 100% wide (full-thickness) crescent-shaped (CS) tears (n = 6) and reverse L-shaped (rLS) tears (n = 6) in the supraspinatus tendon and measured strain and kinematics during active humeral elevation until 30°. RESULTS: Both tear shapes and sizes led to an increase in internal rotation, supraspinatus loading force, and superior translation of the humerus. For the 100% wide tear size, anterior translation was observed in the CS tear group, whereas in the rLS tear group, this translation occurred mainly in the posterior direction. Strain was higher in the infraspinatus during the first 25° of abduction in comparison with the supraspinatus tendon in both tear shape groups. An analysis of the anterior and posterior tear borders showed a higher strain concentration on the same side of the tear in the CS tear group with 50% and 100% wide tears. CONCLUSIONS: The influence of different tear shapes on translation in the anterior-posterior direction was evident as both CS and rLS tears led to an oppositely directed translation of the humeral head. The strain analysis showed a stress-shielding effect of the infraspinatus at the beginning of abduction. Therefore, special attention must be paid to correctly identify the tear extension and adequately reconstruct the rotator cuff footprint. Moreover, the constant location of maximum strain in the CS tear group may lead to an earlier progression than in the rLS tear group.

Revisability of polyetheretherketone suture anchors utilised in primary and revision Bankart repair.

BACKGROUND: Polyetheretherketone (PEEK) suture anchors are frequently used in Bankart shoulder stabilisation. This study analyzed the primary stability and revisability of PEEK anchors in-vitro in case of primary Bankart repair and revision Bankart repair after failed primary repair. METHODS: To simulate primary Bankart repair, 12 anchors (Arthrex PEEK PushLock® 3.5 mm) were implanted in 1, 3, 5, 7, 9 and 11 o'clock positions in cadaveric human glenoids and then cyclically tested. To simulate revision Bankart repair, 12 anchors were implanted in the same manner, over-drilled and 12 new anchors of the same diameter were implanted into the same bone socket as the primary anchors and then cyclically tested. The maximum failure loads (Fmax), system displacements, force at clinical failure and modes of failure were recorded. RESULTS: One primary anchor failed prematurely due to a technical problem. Three out of 12 revision anchors (25%) dislocated while setting the 25 N preload. The Fmax, the displacement and clinical failure of the remaining 9 revision anchors were non-significant when compared to the 11 primary repair anchors. The main mode of failure in the primary and revision Bankart surgery group was suture slippage. Anchor dislocations were observed four times in the primary and once in the revision repair groups. CONCLUSIONS: Revision Bankart repair using PEEK anchors of the same diameter in a pre-existing bone socket is possible but bears high risk of premature anchor failure and can jeopardize the reconstruction. PEEK suture anchor in revision Bankart surgery should be implanted in a new bone socket if possible.

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

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

Third-generation autologous chondrocyte implantation after failed bone marrow stimulation leads to inferior clinical results.

PURPOSE: Third-generation autologous chondrocyte implantation (ACI) is an established and frequently used method and successful method for the treatment of full-thickness cartilage defects in the knee. There are also an increasing number of patients with autologous chondrocyte implantation as a second-line therapy that is used after failed bone marrow stimulation in the patient's history. The purpose of this study is to investigate the effect of previous bone marrow stimulation on subsequent autologous chondrocyte implantation therapy. In this study, the clinical results after the matrix-based autologous chondrocyte implantation in the knee in a follow-up over 3 years postoperatively were analysed. METHODS: Forty patients were included in this study. A total of 20 patients with cartilage defects of the knee were treated with third-generation autologous chondrocyte implantation (Novocart® 3D) as first-line therapy. The mean defect size was 5.4 cm2 (SD 2.6). IKDC subjective score and VAS were used for clinical evaluation after 6, 12, 24 and 36 months postoperatively. The results of these patients were compared with 20 matched patients with autologous chondrocyte implantation as second-line therapy. Matched pair analysis was performed by numbers of treated defects, defect location, defect size, gender, age and BMI. RESULTS: Both the first-line (Group I) and second-line group (Group II) showed significantly better clinical results in IKDC score and VAS score in the follow-up over 3 years compared with the preoperative findings. In addition, Group I showed significantly better results in the IKDC and VAS during the whole postoperative follow-up after 6, 12, 24 and 36 months compared to Group II with second-line autologous chondrocyte implantation (IKDC 6 months p = 0.015, 1 year p = 0.001, 2 years p = 0.001, 3 years p = 0.011). Additionally, we found a lower failure rate in Group I. No revision surgery was performed in Group I. The failure rate in the second-line Group II was 30%. CONCLUSION: This study showed that third-generation autologous chondrocyte implantation is a suitable method for the treatment of full-thickness cartilage defects. Both, Group I and Group II showed significant improvement in our follow-up. However, in comparing the results of the two groups, autologous chondrocyte implantation after failed bone marrow stimulation leads to worse clinical results. LEVEL OF EVIDENCE: III.

Influence of bone density on morphologic cement penetration in minimally invasive tibial unicompartmental knee arthroplasty: an in vitro cadaver study.

BACKGROUND: Unicompartmental knee arthroplasty is an established treatment option for anteromedial osteoarthritis. However, large registry studies report higher rates of aseptic loosening compared to total knee arthroplasty. The objective of this study was to assess the impact of bone density on morphological cement penetration. Moreover, an alternative regional bone density measuring technique was validated against the established bone mineral density assessment. METHODS: Components were implanted on the medial side of 18 fresh-frozen cadaver knees using a minimally invasive approach. Bone density has been quantified prior to implantation using Hounsfield units and bone mineral density. Morphological cement penetration has been assessed in different areas and was correlated with local bone density. FINDINGS: A highly significant correlation between Hounsfield units and trabecular bone mineral density was detected (r = 0.93; P < 0.0001), and local bone density was significantly increased in the anterior and posterior area (P = 0.0003). The mean cement penetration depth was 1.5 (SD 0.5 mm), and cement intrusion into trabecular bone was interrupted in 31.8% (SD 23.7%) of the bone-cement interface. Bone density was correlated significantly negative with penetration depth (r = - 0.31; P = 0.023) and positive with interruptions of horizontal interdigitating (r = + 0.33; P = 0.014). Cement penetration around the anchoring peg was not significantly correlated with bone density. INTERPRETATION: Areas with high bone density were characterized by significantly lower penetration depths and significantly higher areas without cement penetration. Anchoring pegs facilitate cement intrusion mechanically. Regional quantification of bone density using Hounsfield units is a simple but valuable extension to the established determination of bone mineral density.

Periprosthetic bone quality affects the fixation of anatomic glenoids in total shoulder arthroplasty: in vitro study.

BACKGROUND: Glenoid loosening, a common complication of shoulder arthroplasty, could relate to implant design and bone quality. However, the role of bone density has not been tested experimentally yet. In this study, tests on cadaveric specimens of varying bone density were performed to evaluate the effects of bone quality on loosening of typical anatomic glenoid implants. METHODS: Cadaveric scapulae scanned with a quantitative computed tomography scanner to determine bone mineral density (BMD) were implanted with either pegged or keeled cemented glenoid components and tested under constant glenohumeral load while a humeral head component was moved cyclically in the inferior and superior directions. Implant superior and inferior edge lifting, defined as displacement from the underlying bone, was measured with linear variable differential transducers until we reached 23,000 test cycles, and statistical testing was performed for differences in edge lifting due to implant design and related to periprosthetic BMD. RESULTS: Edge lifting was statistically significant at all time points, but on average, implant design had no effect. Lifting was highest in specimens in which BMD below the lifting edge was lower, with trends of increased displacement with decreased BMD. CONCLUSIONS: Implant lifting was greater in glenoids of lower bone density for both implant designs. This finding suggests that fixation failure will most likely occur in bone of lower density and that the fixation design itself may play a secondary role.

Graft Hypertrophy After Third-Generation Autologous Chondrocyte Implantation Has No Correlation With Reduced Cartilage Quality: Matched-Pair Analysis Using T2-Weighted Mapping.

BACKGROUND: Graft hypertrophy is common after matrix-based autologous chondrocyte implantation (ACI) in the knee joint. However, it is not clear whether graft hypertrophy is a complication or an adjustment reaction in the cartilage regeneration after ACI. PURPOSE: To analyze the cartilage quality of the ACI regeneration with graft hypertrophy using T2-weighted mapping. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 91 patients with isolated cartilage defects (International Cartilage Repair Society [ICRS] grade III-IV) of the knee were treated with Novocart 3D, a third-generation, matrix-based, ACI procedure in the knee joint. All patients were evaluated with a standardized magnetic resonance imaging protocol after 3, 6, 12, 24, 36, and 48 months postoperatively. For morphological and biochemical assessment, the T2-weighted relaxation times of the ACI grafts as well as the healthy surrounding cartilage were determined. The results of the 20 patients with graft hypertrophy (hypertrophic group) were compared with the results of 21 matched patients without graft hypertrophy (nonhypertrophic group) after ACI. Match-paired analysis was performed by comparison of age, defect size, and body mass index. RESULTS: The T2-weighted relaxation times of the ACI graft showed significant improvement, with values decreasing from 52.1 milliseconds to 33.3 milliseconds after 48 months. After 12 months, the T2-weighted relaxation times were constant and comparable with the healthy surrounding cartilage. Graft hypertrophy was seen in 22% (n = 20) of the patients who underwent ACI. A significant difference in T2-weighted relaxation times between the hypertrophic and nonhypertrophic ACI grafts could not be found except after 36 months (hypertrophic T2-weighted relaxation time/nonhypertrophic T2-weighted relaxation time: 3 months, 48.0/56.4 ms, P = .666; 6 months, 45.6/42.5 ms, P = .280; 12 months, 39.3/34.7 ms, P = .850; 24 months, 34.8/32.2 ms, P = .742; 36 months, 34.6/38.2 ms, P = .030; 48 months, 34.2/32.3 ms, P = .693). CONCLUSION: The T2-weighted relaxation time of the ACI graft cartilage showed significant improvements over the observation period of 4 years postoperatively. After 2 years, graft maturation was completed. Graft hypertrophy after ACI was seen in 22% of the patients. Reduced cartilage quality could not be found in patients with graft hypertrophy after ACI.

[Significance of Matrix-augmented Bone Marrow Stimulation for Treatment of Cartilage Defects of the Knee: A Consensus Statement of the DGOU Working Group on Tissue Regeneration]. / Stellenwert der matrixaugmentierten Knochenmarkstimulation in der Behandlung von Knorpelschäden des Kniegelenks: Konsensusempfehlungen der AG Klinische Geweberegeneration der DGOU.

Surgical principles for treatment of full-thickness cartilage defects of the knee include bone marrow stimulation techniques (i.e. arthroscopic microfracturing) and transplantation techniques (i.e. autologous chondrocyte implantation and osteochondral transplantation). On the basis of increasing scientific evidence, indications for these established therapeutical concepts have been specified and clear recommendations for practical use have been given. Within recent years, matrix-augmented bone marrow stimulation has been established as a new treatment concept for chondral lesions. To date, scientific evidence is limited and specific indications are still unclear. The present paper gives an overview of available products as well as preclinical and clinical scientific evidence. On the basis of the present evidence and an expert consensus from the "Working Group on Tissue Regeneration" of the German Orthopaedic and Trauma Society (DGOU), indications are specified and recommendations for the use of matrix-augmented bone marrow stimulation are given. In principle, it can be stated that the various products offered in this field differ considerably in terms of the number and quality of related studies (evidence level). Against the background of the current data situation, their application is currently seen in the border area between cell transplantation and bone marrow stimulation techniques, but also as an improvement on traditional bone marrow stimulation within the indication range of microfracturing. The recommendations of the Working Group have preliminary character and require re-evaluation after improvement of the study situation.

Allogenic Myocytes and Mesenchymal Stem Cells Partially Improve Fatty Rotator Cuff Degeneration in a Rat Model.

PURPOSE: Rotator cuff (RC) tears result not only in functional impairment but also in RC muscle atrophy, muscle fattening and eventually to muscle fibrosis. We hypothesized that allogenic bone marrow derived mesenchymal stem cells (MSC) and myocytes can be utilized to improve the rotator cuff muscle fattening and increase the atrophied muscle mass in a rat model. METHODS: The right supraspinatus (SSP) tendons of 105 inbred rats were detached and muscle fattening was provoked over 4 weeks; the left side remained untouched (control group). The animals (n = 25) of the output group were euthanized after 4 weeks for reference purposes. The SSP-tendon of one group (n = 16) was left unoperated to heal spontaneously. The SSP-tendons of the remaining 64 rats (4 groups with n = 16) were repaired with transosseous sutures. One group received a saline solution injection in the SSP muscle belly, two other groups received 5 × 106 allogenic myocytes and 5 × 106 allogenic MSC injections from donor rats, respectively, and one group received no additional treatment. After 4 weeks of healing, the supraspinatus muscle mass was compared quantitatively and histologically to all the treated groups and to the untreated contralateral side. RESULTS: In the end of the experiments at week 8, the myocyte and MCS treated groups showed a significantly higher muscle mass with 0.2322 g and 0.2257 g, respectively, in comparison to the output group (0.1911 g) at week 4 with p < 0.05. There was no statistical difference between the repaired, treated, or spontaneous healing groups at week 8. Supraspinatus muscle mass of all experimental groups of the right side was significantly lower compared to the untreated contralateral muscle mass. CONCLUSION: This defect model shows that the injection of allogenic mycocytes and MSC in fatty infiltrated SSP muscles is better than no treatment and can partially improve the SSP muscle belly fattening. Nevertheless, a full restoration of the degenerated and fattened rotator cuff muscle to its original condition is not possible using myocytes and MSC in this model.

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

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

Biodegradable spacer reduces the subacromial pressure: A biomechanical cadaver study.

BACKGROUND: Failure after rotator cuff repair remains a major clinical problem and could be related to excessive pressures from the acromion. Previous studies with irreparable tears showed good clinical results of tendon healing with arthroscopic insertion of a protective biodegradable spacer balloon between the repaired tendon and the acromion. One hypothesis is that compression pressures on the repaired tendon will be reduced by the spacer. This cadaver study aimed to investigate the effects of this subacromial spacer on compression pressures over a repaired supraspinatus tendon in passive motion. METHODS: Rotator cuff tear and repair were performed in six fresh-frozen cadaveric shoulders, followed by insertion of a biodegradable subacromial spacer. Specimens were tested using a passive shoulder simulator for abduction-adduction, flexion-extension and internal-external rotations. A sensor positioned below the acromion was used to measure compression pressure changes through passive range of motion before and after placement of a subacromial spacer. Peak pressures were measured in adduction-abduction motion, near 90° abduction. FINDINGS: Both the mean and peak pressures in abduction-adduction were significantly reduced after insertion of the subacromial spacer (from mean 121.7 (SD 9.5) MPa to 51.5 (SD 1.2) MPa and from peak 1749.6 (SD 80.7) MPa to 535.1 (SD 27.6) MPa) (P<0.0001). INTERPRETATION: The reduced peak pressures and wider load distributions over the sensor during both passive abduction-adduction and flexion-extension motions suggest that the use of the spacer will lead to reduced wear of the repair in patients, and potentially prevent rotator cuff re-tear after surgical repair.

Reference Values of Flexion and Supination in the Elbow Joint of a Cohort without Shoulder Pathologies.

BACKGROUND: After surgery of the long head of the biceps tendon, the examination of the biceps brachii muscle function and strength is common clinical practice. The muscle strength is usually compared with the uninjured contralateral side or with a matched pair group assuming that the uninjured side can be used as an appropriate reference. HYPOTHESIS/PURPOSE: The purpose of this study was to define reference values of the supination and flexion strength in the elbow joint and to investigate the influence of the arm positions and various anthropometric factors. METHODS: 105 participants without any shoulder pathologies were enrolled. A full medical history was obtained and a physical examination was performed. The bilateral isometric testing included the supination torque in various forearm positions and elbow flexion strength with a custom engineered dynamometer. Multiple linear regression analysis was used to investigate the correlation of the strength and anthropometric factors. RESULTS: Only age and gender were significant supination and flexion strength predictors of the elbow. Hence, it was possible to calculate a gender-specific regression line for each forearm position to predict the age-dependent supination torque. The supination strength was greatest with the arm in 90° elbow flexion and the upper arm in full pronation.

Matrix based autologous chondrocyte implantation in children and adolescents: a match paired analysis in a follow-up over three years post-operation.

PURPOSE: The aim of this study is the investigation of the clinical results after third generation autologous chondrocyte implantation in the knee in a follow-up over three years post-operation. Our primary focus is on the effects of this procedure on children and adolescent patients as there is a lack of knowledge regarding the clinical outcomes in children/adolescents in particular when compared with adults. METHODS: A total of 40 patients (43 defects) <20 years with cartilage defects of the knee were treated with third generation ACI (Novocart® 3D). These defects were caused by osteochondritis dissecans (n = 13), acute trauma (<12 months) (n = 9), old trauma (>12 months) (n = 5) or unknown pathology (n = 13). The mean defect size was 5.2 cm2. IKDC subjective score and VAS (at rest and during activity) were used for clinical evaluation after 6, 12, 24 and 36 months post-operatively. The results of these patients were compared with 40 matched adult patients. Match paired analysis was performed by numbers of treated defects, defect location and defect size. All cartilage defects were arthroscopically classified with IKDC grade III-IV. All adult patients in the control group were treated with matrix based autologous chondrocyte implantation. RESULTS: All patients showed significantly better clinical results compared with the pre-operative findings in the follow-up over three years. We observed significantly better results in the IKDC score and VAS during the whole postoperative follow-up in children and adolescents after six, 12, 24 and 36 months compared with the adult control group. The IKDC score improved from 46.5 preoperative to 77.5 (+31) after three years in children and adolescents. Similarly, significantly lower stress pain after six months and one, two and three years was found in this group. CONCLUSION: This study showed that third generation autologous chondrocyte implantation is a suitable method for the treatment of full cartilage defects in children and adolescents.

Testing the feasibility and safety of the Nintendo Wii gaming console in orthopedic rehabilitation: a pilot randomized controlled study.

INTRODUCTION: The Nintendo Wii game console is already used as an additional training device for e.g. neurological wards. Still there are limited data available regarding orthopedic rehabilitation. The authors' objective was to examine whether the Nintendo Wii is an appropriate and safe tool in rehabilitation after orthopedic knee surgery. MATERIAL AND METHODS: A prospective, randomized, controlled study comparing standard physiotherapy vs. standard physiotherapy plus game console training (Wii group) in patients having anterior cruciate ligament (ACL) repair or knee arthroplasty was conducted. The subjects of the Wii group (n = 17; mean age: 54 ±19 years) performed simple knee exercises daily under the supervision of a physiotherapist in addition to the normal rehabilitation program. The patients of the control group (n = 13; 52 ±18 years) were treated with physiotherapy only. The participants of both groups completed a questionnaire including the International Knee Documentation Committee (IKDC) score, the Modified Cincinnati Rating System and the Tegner Lysholm Knee Score prior to the operation, before discharge from hospital and four weeks after treatment. RESULTS: There was no significant difference in the score results between the Wii and the control group (p > 0.05). CONCLUSIONS: We demonstrated that physiotherapy using the Nintendo Wii gaming console after ACL reconstruction and knee arthroplasty does not negatively influence outcome. Because training with the Wii device was highly accepted by patients, we see an opportunity whereby additional training with a gaming console for a longer period of time could lead to even better results, regarding the training motivation and the outcome after orthopedic surgery.

Scaffold-free Scleraxis-programmed tendon progenitors aid in significantly enhanced repair of full-size Achilles tendon rupture.

AIM: Currently there is no effective approach to enhance tendon repair, hence we aimed to identify a suitable cell source for tendon engineering utilizing an established clinically relevant animal model for tendon injury. MATERIALS & METHODS: We compared, by in-depth histomorphometric evaluation, the regenerative potential of uncommitted human mesenchymal stem cells (hMSC) and Scleraxis (Scx)-programmed tendon progenitors (hMSC-Scx) in the healing of a full-size of rat Achilles tendon defect. RESULTS: Our analyses clearly demonstrated that implantation of hMSC-Scx, in contrast to hMSC and empty defect, results in smaller diameters, negligible ectopic calcification and advanced cellular organization and matrix maturation in the injured tendons. CONCLUSION: Scaffold-free delivery of hMSC-Scx aids in enhanced repair in a clinically translatable Achilles tendon injury model.

Analysis of the autologous chondrocyte quality of matrix-based autologous chondrocyte implantation in the knee joint.

PURPOSE: Matrix based autologous chondrocyte implantation is an established method for treatment of full cartilage defects in the knee joint, but little is known about the influence of the implanted autologous chondrocyte quality and its clinical value. The aim of this study is to evaluate the influence of the gene expression of the implanted autologous chondrocytes on the clinical outcomes in the follow-up period of three years. METHODS: Biological parameters of the implanted chondrocytes were analysed histologically and immunohistologically. An analysis of the gene expression of the relevant chondrogenic dedifferentiation markers was performed as well. In order to detect the rate of apoptosis, we analysed specific apoptosis markers. To evaluate the clinical outcome, the International Knee Documentation Committee (IKDC) subjective score and the visual analogue scale (VAS) were used pre-operatively and after 0.5, one, two and three years. RESULTS: Significantly improved clinical scores were observed. The subjective IKDC score increased from 50.6 ± 20.7 points to 69.3 ± 26.1 points at three years (p = 0.001). The implanted chondrocytes showed a typical expression of the chondrogenic markers with a high rate of collagen type II expression without dedifferentiation. The analysed differentiation, dedifferentiation and apoptosis markers showed no influence on the clinical outcome. CONCLUSIONS: The implanted autologous chondrocytes have a high chondrogenic quality with a high rate of collagen type II expression without dedifferentiation. An influence of differentiation, de-differentiation and apoptosis marker gene expression on the clinical outcomes could not be found in a follow-up period of three years. LEVEL OF EVIDENCE: Case series; Level of evidence, 3.

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

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