Michael Jagodzinski

Outcomes and Risks of Operative Treatment of Rupture of the Anterior Cruciate Ligament in Children and Adolescents

PURPOSE The aim of this meta-analysis was to evaluate the clinical outcomes and risks of anterior cruciate ligament (ACL) surgery in children and adolescents. METHODS We electronically searched Medline, the Cochrane Controlled Trial Database, Embase, and Medpilot for studies on surgical treatment for ACL ruptures in skeletally immature patients. We extracted baseline demographics, follow-up intervals, surgical details (i.e., ligament suture or reconstruction, physeal-sparing or transphyseal techniques, type of transplant, and methods of fixation). Endpoints comprised rates of growth disturbances and reruptures, as well as knee function (measured by the International Knee Documentation Committees documentation system and the Lysholm score). Unweighted overall effect sizes (risks, risk ratios [RRs], and means of functional scores) were estimated by use of crude nominators and denominators, and random-effects meta-regression analysis was used for weighted data synthesis. RESULTS A total of 55 articles reporting on 935 patients (median age, 13 years; range, 1.5 to 16 years) were suitable for the study. After a median follow-up of 40 months (range, 14 to 89 months), the weighted rate of leg-length differences or axis deviations was 1.8% (95% confidence interval [CI], 0% to 3.9%] and that of reruptures was 4.8% (95% CI, 2.9% to 6.7%). Excellent or good function (International Knee Documentation Committee grade A or B) was achieved in 84.2% (95% CI, 75.8% to 92.6%) of all knees, and Lysholm scores averaged 96.3 (95% CI, 95.5 to 97.2). Transphyseal reconstruction was associated with a significantly lower risk of leg-length differences or axis deviations compared with physeal-sparing techniques (1.9% v 5.8%; RR, 0.34; 95% CI, 0.14 to 0.81) but had a higher risk of rerupture (4.2% v 1.4%; RR, 2.91; 95% CI, 0.70 to 12.12). Sutures did not result in any growth disturbances, with a weighted rerupture rate of 4.6% (95% CI, 2.6 to 6.7). Fixation far from the joint line fared better than close fixation with regard to this endpoint (1.4% v 3.2%; RR, 0.42; 95% CI, 0.09 to 1.93). Bone-patellar tendon-bone grafts, which are also less likely to fail, were associated with higher risks of leg-length differences or axis deviations than were hamstrings (3.6% v 2.0%; RR, 1.82; 95% CI, 0.66 to 5.03). Meta-regression did not show a significant impact of the publication year on event rates. CONCLUSIONS This meta-analysis showed low rates of leg-length differences or axis deviations and graft failures after ACL reconstruction in skeletally immature patients. Hamstring transplants may lower the risk of leg-length differences or axis deviations, and physeal-sparing techniques may increase the risk. Randomized controlled trials are needed to clarify important issues in managing ACL ruptures in children and adolescents. LEVEL OF EVIDENCE Level IV, meta-analysis of case series.

Achilles Tendon and Paratendon Microcirculation in Midportion and Insertional Tendinopathy in Athletes

Background Neovascularisation can be detected qualitatively by Power Doppler in Achilles tendinopathy. Quantitative data regarding tendon microcirculation have not been established and may be substantial. Purpose To assess the microcirculation of the Achilles tendon and the paratendon in healthy volunteers as well as in athletes with either midportion or insertional tendinopathy. Study Design Cohort study; Level of evidence, 2. Methods In 66 physically active volunteers, parameters of Achilles tendon and paratendon microcirculation, such as tissue oxygen saturation, relative postcapillary venous filling pressures, and microcirculatory blood flow, were determined at rest at 2-mm and 8-mm tissue depths. Forty-one patients never had Achilles pain (25 men, 27 ± 8 years), 14 patients had insertional pain (7 men, 29 ± 8 years), and 11 patients had midportion tendinopathy (7 men, 38 ± 13 years, not significant). Results Achilles tendon diameter 2 cm and 6 cm proximal to the insertion was increased in symptomatic tendons. Compared with the uninvolved opposite tendon, deep microcirculatory blood flow was significantly elevated at insertional (160 ± 79 vs 132 ± 42, P<. 05) as well as in midportion tendinopathy (150 ± 74 vs 119 ± 34, P<. 05). The microcirculation in the uninvolved opposite tendon and the normal athlete controls were not significantly different from each other (132 ± 42 insertional asymptomatic vs 119 ± 34 mid-portion vs 120 ± 48 healthy tendon). Insertional paratendon deep microcirculatory flow was elevated in all groups, whereas tissue oxygen saturation and relative postcapillary venous filling pressures were not significantly different. Conclusion Microcirculatory blood flow is significantly elevated at the point of pain in insertional and midportion tendinopathy. Postcapillary venous filling pressures are increased at both the midportion Achilles tendon and the midportion paratendon, whereas tissue oxygen saturation is not different among the studied groups. We found no evidence of an abnormal microcirculation of the asymptomatic limb in Achilles tendinopathy.

Influence of perfusion and cyclic compression on proliferation and differentiation of bone marrow stromal cells in 3-dimensional culture

Until now, there has been no in vitro model that duplicates the environment of bone marrow. The purpose of this study was to analyze proliferation and differentiation of human bone marrow stromal cells (hBMSC) under the influence of continuous perfusion and cyclic mechanical loading. hBMSC of seven individuals were harvested, grown in vitro, and combined. 10(6) hBMSC were seeded on a bovine spongiosa disc and incubated in a bioreactor system. Cell culture was continued using three different conditions: Continuous perfusion (group A), 10% cyclic compression at 0.5Hz (group B) and static controls (group C). After 24h, 1, 2, and 3 weeks, we determined cell proliferation (MTS-assay) and osteogenic differentiation (osteocalcin ELISA, Runx2 mRNA). Tenascin-C mRNA was quantified to exclude fibroblastic differentiation. In groups A and B, proliferation was enhanced after 2 weeks (48.6+/-19.6x10(3) (A) and 44.6+/-14.3 x 10(3) cells (B)) and after 3 weeks (46.6+/-15.1 x 10(3) (A) and 44.8+/-10.2 x 10(3) cells (B)) compared with controls (26.3+/-10.8 x 10(3) (2 weeks) and 17.1+/-6.5 x 10(3) cells (3 weeks), p<0.03). Runx2 mRNA was upregulated in both stimulated groups after 1, 2, and 3 weeks compared to control (group A, 1 week: 5.2+/-0.7-fold; p<0.01, 2 weeks: 4.4+/-1.9-fold; p<0.01, 3 weeks: 3.8+/-1.7-fold; p=0.013; group B, 1 week: 3.6+/-1.1-fold, p<0.01, 2 weeks: 4.2+/-2.2-fold, p<0.01; 3 weeks: 5.3+/-2.7-fold, p<0.01). hBMSC stimulated by cyclic compression expressed the highest amount of osteocalcin at all time points (1 week: 294.5+/-88.4 mg/g protein, 2 weeks: 294.4+/-73.3mg/g protein, 3 weeks: 293.1+/-83.6 mg/g protein, p0.03). The main stimulus for cell proliferation in a 3-dimensional culture of hBMSC is continuous perfusion whereas mechanical stimulation fosters osteogenic commitment of hBMSC. This study thereby contributes to the understanding of physical stimuli that influence hBMSC in a 3-dimensional cell culture system.

Influence of perfusion and compression on the proliferation and differentiation of bone mesenchymal stromal cells seeded on polyurethane scaffolds

In the present study, a porous meniscal-shaped scaffold consisting of polyurethane (PU)-based 1, 4-butanediisocyanate (BDI), which provided a 3-D culture condition for human bone mesenchymal stromal cells (hBMSC) was employed. A bioreactor was utilized to produce perfusion and mechanical stimulations. The viability, proliferation and fibro-cartilaginous differentiation of the hBMSC cultured on the PU-based meniscal scaffold were investigated during the perfusion and mechanical stimulation process. In addition, the mechanical properties of the cell-laden scaffolds were examined as well. Our finding indicated that the perfusion (10 ml/min) and on-off cyclic compressions mechanical stimulation (10% strain, 0.5 Hz, 4 times/day, 2 h/time with 4 h of rest thereafter) maintained the viability and promoted the proliferation of hBMSC over 2 weeks. The on-off cyclic compression caused a 1.85 fold increase in equilibrium modulus. Meanwhile, type I procollagen produced by hBMSC was increased for 3.02-fold after 2 weeks culture. On the other hand, the irrigating medium enhanced the synthesis of type III procollagen for 2.24-fold after 2 weeks. Tensile modulus was elevated for 2.02-fold in perfusion group after 1 week, which was decreased after 2 weeks unexpectedly. Our study suggests that the perfusion and on-off compression are promising to enhance the functional properties of the hBMSC-laden PU-based meniscal scaffold.

Bone marrow stromal cells in a liquid fibrin matrix improve the healing process of patellar tendon window defects.

Following injury, ligaments and tendons do not regain their normal biological and biomechanical status. This study analyzed whether an injection of human bone marrow stromal cells (BMSC) or human fibroblast in a liquid fibrin matrix influences the histological results, ultrastructural morphology, mRNA expression of essential extracellular matrix proteins, and material properties of the healing tissue. Standardized full-thickness, full-length defects of the central portion of patellar tendons were created in 96 immunodeficient rats, and filled with human BMSC in a fibrin matrix (BMSC group), human fibroblasts in a fibrin matrix (fibroblast group), or fibrin matrix only (matrix group), or left untreated (defect group). Histological sections revealed more mature tissue formation with more regular patterns of cell distribution in the BMSC group, without signs of ectopic tissue formation into bone or cartilage. Mean collagen fibril diameter and relative area covered by collagen fibrils were significantly higher at 10 and 20 days postoperatively in the BMSC group compared to the defect and matrix groups, and comparable to normal tendon tissue. Further, collagen I mRNA expression, collagen I/collagen III mRNA ratio, and Youngs modulus were significantly increased at 20 days postoperatively in comparison to the defect and matrix groups. In the fibroblast group, only mean collagen fibril diameter was significantly higher compared to the defect group, whereas the other biological and biomechanical parameters were not significantly improved. This study reveals that an injection of BMSC in a liquid fibrin matrix stimulates histological, ultrastructural, molecular biologic, and biomechanical parameters of patellar tendon healing, whereas injection of fibroblasts in fibrin matrix had only minor effects on the stimulation of tendon healing.

Changes of Achilles Midportion Tendon Microcirculation After Repetitive Simultaneous Cryotherapy and Compression Using a Cryo/Cuff

Background Cryotherapy and compression have been shown to decrease pain and improve function. The dosage and timing of these options remain unclear. Purpose To examine the effects of a standardized compression and cryotherapy device (Cryo/Cuff) on midportion Achilles tendon microcirculation during intermittent administration. Study Design Descriptive laboratory study. Methods Twenty-six subjects were included (13 men and 13 women; age, 32.3 ± 12 years; body mass index, 25.4 ± 5 kg/m2). Each underwent three 10-minute applications of the device, followed by a 10-minute recovery period. A continuous real-time assessment of parameters of Achilles tendon midportion microcirculation was performed with a laser Doppler spectrophotometry system. Results Superficial tendon oxygen saturation dropped significantly from 35.9 ± 21 arbitrary units (AU) to 13.5 ± 15, 15.9 ± 16, and 11.1 ± 11 AU (P =. 0001) during each period of cryo-compression, respectively. There was significant increase during the recovery period (55.4 ± 29, 65.2 ± 26, and 65.7 ± 27 AU; P =. 003), up to +83% of the baseline level. At 8-mm tendon depth, cryo-compression preserved local oxygen with -4% (P =. 001) of the baseline level and small but significant increased oxygen saturation of up to +13% (P =. 0001). Relative postcapillary venous tendon filling pressures were favorably reduced both superficially (57% ± 34%, 67% ± 27%, and 64% ± 38%, respectively; P =. 0004) and deep (76% ± 13%, 79% ± 11%, and 78% ± 18%, respectively; P =. 0002). Superficial capillary blood flow was reduced from 48.4 ± 48 to 5 ± 7, 4 ± 5, and 3 ± 4 AU at each period, respectively (–94%, P =. 0003), with increased flow during recovery periods of up to 58 ± 64, 58 ± 79, and 47 ± 71 AU, respectively (+20%, P =. 265). Deep flow was reduced from 197 ± 147 to 66.7 ± 64, 55 ± 46, and 43 ± 39 AU, respectively (–78%, P =. 0002) without increase during recovery periods. Conclusion Cryo/Cuff exerts beneficial effects on the microcirculatory level of the midportion Achilles tendon with decreased capillary blood flow, preserved deep tendon oxygen saturation, and facilitated venous capillary outflow.

Hindlimb Growth After a Transphyseal Reconstruction of the Anterior Cruciate Ligament: A Study in Skeletally Immature Sheep With Wide-Open Physes

Background There is a lot of controversy in the recent literature with regard to the optimal treatment of anterior cruciate ligament (ACL) injuries during growth. Iatrogenic growth disturbance due to physeal damage is a potential complication, forcing many orthopaedic surgeons to treat these injuries conservatively. Hypothesis It is possible to perform a fully transphyseal ACL reconstruction in an ovine model with wide-open physes without creating growth disturbances. Study Design Descriptive laboratory study. Materials and Methods Four-month-old skeletally immature sheep underwent a transphyseal ACL reconstruction of the right knee. The surgical technique followed the criteria known to be essential to avoid growth disturbances in humans; the tibial tuberosity was spared to prevent a genu recurvatum, thermal damage to the growth plates was avoided, the physes were perforated with a small-diameter drill in the center of the growth plate, a soft tissue graft was used, graft fixation was achieved far away from the growth plates, the perforated growth plates were filled by the soft tissue graft, and the graft was moderately pretensioned before fixation. The left knee served as a control. A computer-assisted evaluation of long radiographs (frontal and sagittal plane) of the exarticulated hindlimbs was performed to exactly evaluate the limb alignment, joint orientation, and leg length. The animals were sacrificed in groups of 6 after 3, 6, 12, and 24 weeks. Results No angular deformities or leg-length discrepancies occurred after this transphyseal ACL reconstruction procedure throughout the remaining growth. Conclusion This large-animal study supports the clinical observation that it is possible to perform an ACL reconstruction without creating growth disturbances as long as a number of key principles are followed. Clinical Relevance Previous animal studies argued against ACL reconstruction in skeletally immature patients. This large-animal study provides support for early operative treatment of ACL ruptures even in young patients with open physes.

Repair of a segmental long bone defect in human by implantation of a novel multiple disc graft

Large segmental defects of the weight bearing long bones are very difficult to reconstruct. Current treatment options are afflicted with several limitations and disadvantages. We describe a novel approach to regenerate a segmental long bone defect in a patient using a multiple disc graft. Decellularized bovine trabecular bone discs were seeded with autologous bone marrow cells and cultured in a perfusion chamber for three weeks. Multiple cell-seeded discs were implanted to close a 72 mm defect of the distal tibia in a 58-year-old woman, and fixed by an intramedullary nail. Bone formation was assessed non-invasively by plain radiographs and 18F-labeled sodium fluoride-based co-registration of positron emission- and computed tomography (PET/CT). Bone was actively formed around the grafted defect as early as six weeks after surgery. Because the tibia was sufficiently stabilized, the patient was able to freely walk with full weight bearing 6 weeks after surgery. The uneventful two-year follow-up and the satisfaction of the patient demonstrated the success of the procedure. Therefore the use of multiple cell-seeded disc grafts can be considered as a treatment alternative for patients with segmental long bone defects.

Biodegradable Screw Versus a Press-Fit Bone Plug Fixation for Hamstring Anterior Cruciate Ligament Reconstruction A Prospective Randomized Study

Background Press-fit fixation of a tendon graft has been advocated to achieve tendon-to-bone healing. Hypothesis Fixation of hamstring tendon grafts with a porous bone scaffold limits bone tunnel enlargement compared with a biodegradable interference screw fixation. Study Design Randomized controlled trial; Level of evidence, 1. Methods Between 2005 and 2006, 20 patients (17 men, 3 women) with a primary reconstruction of the anterior cruciate ligament (ACL) were enrolled in this study. Patients were randomized to obtain graft fixation in the tibial tunnel either by means of an interference screw (I) or a press-fit fixation with a porous bone cylinder (P). At 3 months after surgery, a computed tomography (CT) scan of the knee was performed, and tunnel enlargement was analyzed in the coronal and sagittal planes for the proximal, middle, and distal thirds of the tunnel. After 6 months and 1 and 2 years, radiographs of the knee in the sagittal and coronal plane were analyzed for bone tunnel widening. The International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores of both groups were compared after 1 and 2 years. Results The bone tunnel enlargement determined by CT was 106.9% ± 10.9% for group P and 121.9% ± 9.0% for group I (P < .02) in the anteroposterior (AP) plane and 102.8% ± 15.2% versus 121.5% ± 10.1% in the coronal plane (P < .01). The IKDC, Tegner, and Lysholm scores improved in both groups from preoperatively to postoperatively without significant differences between the 2 groups. There was a trend to higher knee stability in group P after 3 months (0.6 ± 1.4 mm vs 1.8 ± 1.5 mm; P = .08). Conclusion Both interference screw and a press-fit fixation lead to a high number of good or very good outcomes after ACL reconstruction. Tibial press-fit fixation decreases the amount of proximal bone tunnel enlargement.

Femoral Press-Fit Fixation of the Hamstring Tendons for Anterior Cruciate Ligament Reconstruction

Background Press-fit fixation of patellar tendon–bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary. For hamstring tendon grafts, no biomechanical data exist of a press-fit procedure. Hypothesis Press-fit femoral fixation of hamstring tendons is mechanically equivalent to press-fit patellar tendon–bone fixation. Study Design Controlled laboratory study. Methods Patellar and hamstring tendons of 30 human cadavers (age, 53.8 ± 18.0 years) were used. An outside-in press-fit fixation with a knot in the semitendinosus and gracilis tendons and an inside-out and outside-in fixation with the tendons wrapped around a bone block were compared with patellar tendon–bone press-fit fixation in 30 ovine femora. Constructs were cyclically strained and then loaded until failure. Maximum load to failure, stiffness, and elongation during failure testing and cyclical loading were investigated. Results The maximum load to failure was 561 ± 309 N for the patellar tendon, 599 ± 234 N for the semitendinosus/gracilis tendons knot construct, 678 ± 231 for the semitendinosus/gracilis tendons bone construct inserted outside in, and 339 ± 236 for the semitendinosus/gracilis tendons bone construct inserted inside out (inferior to the others; analysis of variance, Dunn test, P < .01). Stiffness of the constructs averaged 134 ± 32 N/mm for the patellar tendon, 124 ± 21 N/mm for the knot construct, 118 ± 27 N/mm for the outside-in fixation, and 117 ± 23 N/mm for inside-out fixation. Elongation during initial cyclical loading was 0.7 ± 0.6 mm for the patellar tendon, 1.6 ± 0.5 mm for the knot construct, 1.9 ± 1.2 mm for the outside-in fixation, and 1.9 ± 0.9 mm for the inside-out fixation (significantly larger for all semitendinosus/gracilis tendon techniques, P < .05). Conclusions Failure loads for the semitendinosus/gracilis tendons bone construct inserted outside in and the semitendinosus/gracilis tendons knot construct were within the confidence interval of the patellar tendon press-fit fixation. All semitendinosus/gracilis tendon graft techniques exhibited larger elongation during initial cyclical loading than the patellar tendon graft. There was no difference in stiffness between all techniques. Clinical Relevance Two of the 3 hamstring press-fit fixation techniques showed loads to failure similar to the patellar tendon fixation. Preconditioning of the constructs is critical. These results must be interpreted with care because of high standard deviations.