Management after acute injury of the anterior cruciate ligament (ACL). Part 3: Recommendation on surgical treatment.

PURPOSE: The aim of this consensus project was to give recommendations regarding surgical treatment of the anterior cruciate ligament (ACL) injured patient. METHODS: For this consensus process, an expert, steering and rating group was formed. In an initial online meeting, the steering group, together with the expert group, formed various key topic complexes for which multiple questions were formulated. For each key topic, a structured literature search was performed by the steering group. The results of the literature review were sent to the rating group with the option to give anonymous comments until a final consensus voting was performed. Sufficient consensus was defined as 80% agreement. RESULTS: During this consensus process, 30 topics regarding the surgical management and technique of ACL reconstruction were identified. The literature search for each key question resulted in 30 final statements. Of these 30 final statements, all achieved consensus. CONCLUSIONS: This consensus process has shown that surgical treatment of ACL injury is a complex process. Various surgical factors influence patient outcomes. The proposed treatment algorithm can be used as a decision aid for the surgeon. LEVEL OF EVIDENCE: Level V.

Management after acute injury of the anterior cruciate ligament (ACL), part 2: management of the ACL-injured patient.

PURPOSE: The aim of this consensus project was to create a treatment algorithm for the management of the ACL-injured patient which can serve as an aid in a shared decision-making process. METHODS: For this consensus process, a steering and a rating group were formed. In an initial face-to-face meeting, the steering group, together with the expert group, formed various key topic complexes for which various questions were formulated. For each key topic, a structured literature search was performed by the steering group. The results of the literature review were sent to the rating group with the option to give anonymous comments until a final consensus voting was performed. Sufficient consensus was defined as 80% agreement. RESULTS: During this consensus process, 15 key questions were identified. The literature search for each key question resulted in 24 final statements. Of these 24 final statements, all achieved consensus. CONCLUSIONS: This consensus process has shown that ACL rupture is a complex injury, and the outcome depends to a large extent on the frequently concomitant injuries (meniscus and/or cartilage damage). These additional injuries as well as various patient-specific factors should play a role in the treatment decision. The present treatment algorithm represents a decision aid within the framework of a shared decision-making process for the ACL-injured patient. LEVEL OF EVIDENCE: Level V.

Management after acute rupture of the anterior cruciate ligament (ACL). Part 1: ACL reconstruction has a protective effect on secondary meniscus and cartilage lesions.

PURPOSE: The aim of this consensus project was to validate which endogenous and exogenous factors contribute to the development of post-traumatic osteoarthritis and to what extent ACL (anterior cruciate ligament) reconstruction can prevent secondary damage to the knee joint. Based on these findings, an algorithm for the management after ACL rupture should be established. METHODS: The consensus project was initiated by the Ligament Injuries Committee of the German Knee Society (Deutsche Kniegesellschaft, DKG). A modified Delphi process was used to answer scientific questions. This process was based on key topic complexes previously formed during an initial face-to-face meeting of the steering group with the expert group. For each key topic, a comprehensive review of available literature was performed by the steering group. The results of the literature review were sent to the rating group with the option to give anonymous comments until a final consensus voting was performed. Consensus was defined a-priori as eighty percent agreement. RESULTS: Of the 17 final statements, 15 achieved consensus, and 2 have not reached consensus. Results of the consensus were summarized in an algorithm for the management after ACL rupture (infographic/Fig. 2). CONCLUSION: This consensus process has shown that the development of post-traumatic osteoarthritis is a complex multifactorial process. Exogenous (primary and secondary meniscus lesions) and endogenous factors (varus deformity) play a decisive role. Due to the complex interplay of these factors, an ACL reconstruction cannot always halt post-traumatic osteoarthritis of the knee. However, there is evidence that ACL reconstruction can prevent secondary joint damage such as meniscus lesions and that the success of meniscus repair is higher with simultaneous ACL reconstruction. Therefore, we recommend ACL reconstruction in case of a combined injury of the ACL and a meniscus lesion which is suitable for repair. LEVEL OF EVIDENCE: Level V.

Management of anterior cruciate ligament revision in adults: the 2022 ESSKA consensus part III-indications for different clinical scenarios using the RAND/UCLA appropriateness method.

PURPOSE: The aim of the ESSKA 2022 consensus Part III was to develop patient-focused, contemporary, evidence-based, guidelines on the indications for revision anterior cruciate ligament surgery (ACLRev). METHODS: The RAND/UCLA Appropriateness Method (RAM) was used to provide recommendations on the appropriateness of surgical treatment versus conservative treatment in different clinical scenarios based on current scientific evidence in conjunction with expert opinion. A core panel defined the clinical scenarios with a moderator and then guided a panel of 17 voting experts through the RAM tasks. Through a two-step voting process, the panel established a consensus as to the appropriateness of ACLRev for each scenario based on a nine-point Likert scale (in which a score in the range 1-3 was considered 'inappropriate', 4-6 'uncertain', and 7-9 'appropriate'). RESULTS: The criteria used to define the scenarios were: age (18-35 years vs 36-50 years vs 51-60 years), sports activity and expectation (Tegner 0-3 vs 4-6 vs 7-10), instability symptoms (yes vs no), meniscus status (functional vs repairable vs non-functional meniscus), and osteoarthritis (OA) (Kellgren-Lawrence [KL] grade 0-I-II vs grade III). Based on these variables, a set of 108 clinical scenarios was developed. ACLRev was considered appropriate in 58%, inappropriate in 12% (meaning conservative treatment is indicated), and uncertain in 30%. Experts considered ACLRev appropriate for patients with instability symptoms, aged ≤ 50 years, regardless of sports activity level, meniscus status, and OA grade. Results were much more controversial in patients without instability symptoms, while higher inappropriateness was related to scenarios with older age (51-60 years), low sporting expectation, non-functional meniscus, and knee OA (KL III). CONCLUSION: This expert consensus establishes guidelines as to the appropriateness of ACLRev based on defined criteria and provides a useful reference for clinical practice in determining treatment indications. LEVEL OF EVIDENCE: II.

The ACL-deficient knee and the prevalence of meniscus and cartilage lesions: a systematic review and meta-analysis (CRD42017076897).

INTRODUCTION: The purpose of this systematic review and meta-analysis was to analyze and compare the rate of secondary meniscus and cartilage lesions diagnosed at different time points of ACL reconstruction. MATERIALS AND METHODS: A systematic search for articles comparing the rate of secondary meniscus and cartilage lesions diagnosed at different time points of ACL reconstruction was performed. PubMed central was the database used for the literature review. RESULTS: Forty articles out of 1836 were included. In 35 trials (88%), there was evidence of a positive correlation between the rate of meniscus and/or cartilage lesions and the time since ACL injury. This correlation was more evident for the medial meniscus in comparison with the lateral meniscus. In particular, a delay of more than 6 months was critical for secondary medial meniscus injuries [risk ratio 0.58 (95% CI 0.44-0.79)] and a delay of more than 12 months was critical for cartilage injuries [risk ratio 0.42 (95% CI 0.29-0.59)]. Additionally, there is evidence that the chance for meniscal repair decreases as the time since ACL rupture increases. CONCLUSION: Chronic instability in the ACL-deficient knee is associated with a significant increase of medial meniscus injuries after 6 months followed by a significant increase of cartilage lesions after 12 months.

Comparative Analysis of Different Platelet Lysates and Platelet Rich Preparations to Stimulate Tendon Cell Biology: An In Vitro Study.

The poor healing potential of tendons is still a clinical problem, and the use of Platelet Rich Plasma (PRP) was hypothesized to stimulate healing. As the efficacy of PRPs remains unproven, platelet lysate (PL) could be an alternative with its main advantages of storage and characterization before use. Five different blood products were prepared from 16 male donors: human serum, two PRPs (Arthrex, (PRP-ACP); RegenLab (PRP-BCT)), platelet concentrate (apheresis, PC), and PL (freezing-thawing destruction of PC). Additionally, ten commercial allogenic PLs (AlloPL) from pooled donors were tested. The highest concentration of most growth factors was found in AlloPL, whereas the release of growth factors lasted longer in the other products. PRP-ACP, PRP-BCT, and PC significantly increased cell viability of human tenocyte-like cells, whereas PC and AlloPL increased Col1A1 expression and PRP-BCT increased Col3A1 expression. MMP-1, IL-1ß, and HGF expression was significantly increased and Scleraxis expression decreased by most blood products. COX1 expression significantly decreased by PC and AlloPL. No clear positive effects on tendon cell biology could be shown, which might partially explain the weak outcome results in clinical practice. Pooled PL seemed to have the most beneficial effects and might be the future in using blood products for tendon tissue regeneration.

Treatment of osteochondral defects with a combination of bone grafting and AMIC technique.

INTRODUCTION: Osteochondral defects of the knee may cause functional impairment of young and sportively active patients. Different surgical treatment options have been proposed using either one or two step procedures. The aim of the current study was to evaluate mid-term outcomes of combined bone grafting with autologous matrix-associated chondrogenesis (AMIC) for the treatment of large osteochondral defects. MATERIALS AND METHODS: 15 Patients with osteochondrosis dissecans of the medial femoral condyle grade III or IV according to ICRS classification were treated with a single step surgical procedure combining bone grafting and the AMIC procedure. Mean defect size was 4.98 cm2 (± 3.02) and patients were examined at 6, 12 weeks, 6 and 12 month and at mean final follow-up of 49 months (36-61). Patients were evaluated using VAS, IKDC, KOOS, Lysholm, Tegner activity scores and psychological and physical health assessed using the SF 12. MRI evaluation was performed at final follow-up using the MOCART score. RESULTS: Pain had significantly decreased at final follow-up (7.2 ± 1.4 vs. 2.4 ± 2.6) compared to preoperative baseline. All functional scores had improved significantly throughout the follow-up period (IKDC from 36.6 ± 20.6 vs. 72.2 ± 18.7; KOOS 50.0 ± 18.9 vs. 81.7 ± 13.9; LYSHOLM 39.3 ± 19.5 vs. 79.8 ± 15.1). SF12 evaluation showed a significant increase in physical component summary (PCS) (31.2 ± 11.1 preoperative vs. 46.3 ± 9.9 at final follow-up), while mental component summary (MCS) remained stable (51.8 ± 8.9 vs. 57.3 ± 3.3). MOCART score revealed a mean overall score of 77 ± 15 at final follow-up. Integration to the adjacent cartilage was complete in 79%, incomplete in 21%. Defect filling was complete in 64%, incomplete in 36%. CONCLUSION: Significant improvement of knee function and restoration of homogenous cartilage morphology could be achieved with simultaneous AMIC procedure and bone grafting in 2/3 of all patients with large osteochondral lesions at 4 years postoperatively.

Evaluating the potential synergistic benefit of a realignment brace on patients receiving exercise therapy for patellofemoral pain syndrome: a randomized clinical trial.

BACKGROUND: It has been previously shown that exercise programs for patellofemoral pain syndrome (PFPS) can be supported by medially directed taping. Evidence supporting the use of patellar braces is limited because previous studies have been low quality. The aim of this study is to compare the outcomes of patients with PFPS after treatment with a medially directed patellar realignment brace and supervised exercise. METHODS: In a prospective randomized multicenter trial, 156 patients with PFPS were included and randomly assigned to 6 weeks of supervised physiotherapy in combination with the patellar realignment brace, or supervised physiotherapy alone. Outcome measures were the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, numeric analog pain scores, and the Kujala score at baseline, 6 weeks, 3 months, and 1 year after the start of therapy. The patient's self-reported perception of recovery was also assessed at these points. RESULTS: Both treatment groups showed a significant improvement in all outcome measures over the study period. After 6 and 12 weeks of therapy, patients in the brace group had significantly higher KOOS sub-scale scores, a higher mean Kujala score, and less pain while climbing stairs or playing sports. After 54 weeks a group difference could be only detected for the KOOS ADL sub-scale. CONCLUSION: The use of a medially directed realignment brace leads to better outcomes in patients with PFPS than exercise alone after 6 and 12 weeks of treatment. After 1 year of follow-up this positive effect diminished.

The Patella Pro study - effect of a knee brace on patellofemoral pain syndrome: design of a randomized clinical trial (DRKS-ID:DRKS00003291).

BACKGROUND: Patellofemoral pain syndrome (PFPS) is a frequent cause of anterior knee pain predominantly affecting young female patients who do not have significant chondral damage. Development of PFPS is probably multifactorial, involving various knee, hip, and foot kinematic factors. Biomechanical studies have described patellar maltracking and dynamic valgus (functional malalignment) in patients with patellofemoral pain syndrome. The literature provides evidence for short-term use of nonsteroidal anti-inflammatory drugs; short-term medially directed taping; and exercise programs focusing on the lower extremity, hip, and trunk muscles. Evidence supporting the use of patellar braces is limited because previous studies have been low quality. The aim of this article is to publish the design of a prospective randomized trial that examines the outcomes of patients with PFPS after treatment with a new patellar brace (Patella Pro) that applies medially directed force on the patella. METHODS/DESIGN: For this multicenter trial, 156 patients (adolescents and young adults) with PFPS were recruited from orthopedic practices and orthopedic hospitals and randomly allocated to 3 months of supervised physiotherapy in combination with the Patella Pro brace or supervised physiotherapy alone. The primary outcome measures are pain (numerical analog scale); knee function (Kujala score and Knee Injury and Osteoarthritis Outcome Score); and self-reported perception of recovery at baseline, 6 weeks, 3 months, and 1 year. DISCUSSION: Only limited evidence for the use of a patellar brace for the treatment of PFPS exists in the literature. Disputable evidence for the use of orthoses for PFPS patients has been presented in one meta-analysis, in which only one of three studies found the effect of a medially directed patellar brace to be significant. Because of these low-quality studies, the authors concluded that this evidence should be regarded as limited, and we feel there is a need for further well-designed studies to evaluate the effect of patellar bracing on PFPS-related pain. The Patella Pro study is a prospective randomized trial in which supervised physiotherapy in combination with a patellar brace is compared with supervised physiotherapy alone. This trial started in April 2012 and finished in October 2013. TRIAL REGISTRATION: DRKS-ID:DRKS00003291, January 3rd, 2012.

Intra-articular remodelling of hamstring tendon grafts after anterior cruciate ligament reconstruction.

PURPOSE: A summary is provided on the existing knowledge about the specific healing phases of the intra-articular hamstring tendon graft used for ACL reconstruction. Differences between human and animal in vivo studies are explained, and implications for the postoperative time period are laid out. METHODS: A systematic review of the existing literature was performed on the topic of tendon remodelling of hamstring grafts in ACL reconstruction using Medline database. Publications between 1982 and 2012 were included. Special focus was directed on in vivo human and animal studies analysing intra-articular free tendon graft remodelling. RESULTS: Animal and human in vitro and vivo researches have demonstrated three characteristic stages of graft healing after ACL reconstruction: an early graft healing phase with central graft necrosis and hypocellularity and no detectable revascularization of the graft tissue, followed by a phase of proliferation, the time of most intensive remodelling and revascularization and finally, a ligamentization phase with characteristic restructuring of the graft towards the properties of the intact ACL. However, a full restoration of either the biological or biomechanical properties of the intact ACL is not achieved. CONCLUSION: Significant knowledge on human cruciate ligament remodelling has been added in the understanding of the processes during the course of graft healing. Most importantly, the remodelling process in humans is prolonged compared to animal studies. While today´s rehabilitation protocols are often extrapolated from findings of animal in vivo healing studies, current findings of human in vivo healing studies might require new post-operative regimens following hamstring ACL reconstruction.

Prevalence and patterns of anatomical risk factors in patients after patellar dislocation: a case control study using MRI.

OBJECTIVE: To assess anatomical risk factors in patients after lateral patellar dislocation (LPD) and controls using MRI. METHODS: MR images of 186 knees after LPD and of 186 age- and gender-matched controls were analysed. The presence of trochlear dysplasia was assessed by evaluation of trochlear inclination, facet asymmetry, and trochlear depth; patella alta was evaluated by the Insall-Salvati index and Caton-Deschamps index; the lateralised force vector was measured by the tibial tuberosity-trochlear groove (TT-TG) distance. RESULTS: Compared with controls, dislocators had significantly lower values for all three parameters of trochlear dysplasia (-32 %, -32 %, -44 %) and significantly higher values for patella alta (+14 %,+13 %) and TT-TG (+49 %) (all P < 0.001). Trochlear dysplasia was observed in 112 dislocators (66 %), of whom 61 (36 %) additionally had patella alta and 15 (9 %) an abnormal TT-TG. As isolated risk factors, patella alta (15 %) and abnormal TT-TG (1 %) were rare. Only 25 dislocators (15 %) had no anatomical risk factors. Trochlear dysplasia in conjunction with abnormal TT-TG or patella alta is associated with a 37- and 41-fold higher risk. CONCLUSION: Most dislocators have anatomical risk factors, varying in severity and constellation.

Impact of tendon suturing on the interference fixation strength of quadrupled hamstring tendon grafts.

INTRODUCTION: Interference screw fixation of soft tissue grafts has been a widely used fixation technique for cruciate ligament reconstruction. Suturing of the graft construct prior to graft fixation has been proposed to increase fixation strength; however, the effect on mechanical properties has not been well characterized. The goal of this study was to determine whether uniform suturing of the tendon graft affects (1) ultimate fixation strength of the hamstring tendon graft and (2) motion of the tendon in the bone tunnel during cyclic loading when comparing sutured grafts vs. unsutured grafts. METHOD: Eight pairs of matched mature porcine tibias (age <2 years) and eight paired fresh-frozen human quadrupled hamstring tendon grafts were used. One quadrupled graft from each pair was placed into one of two groups. In the group A a single cerclage suture 3 cm from the doubled end of the graft was placed to join the four tendon strands. In group B a heavy suture was used to tightly unite the four strands of tendon graft to provide a better grip for the interference screw during fixation. The grafts were placed in tibial bone tunnels that matched the graft's diameter and fixed with an interference screw. The looped end of the graft and the attached tibia were rigidly fixed in a material testing machine. The graft constructs were subjected to 100 cycles of 20-250 N load, followed by a load-to-failure test. In addition, a motion analysis system was used during cyclic testing to better determine the amount of elongation at the graft-tunnel interface. Statistical analysis of the failure load and stiffness and the overall elongation following cyclical loading was performed using the Wilcoxon rank sum test. Level of significance was set at p < 0.05. RESULTS: Elongation at the tendon-bone interface during sub-maximal cyclic loading was 2.4 ± 1.4 mm (unsutured) vs. 2.0 ± 0.7 mm (sutured) (p > 0.05). Failure load of the grafts without sutures (634 ± 86 N) was significantly lower than with the sutures (837 ± 183 N). Ultimate stiffness of group A (283 ± 34 N/mm) was lower than that of group B (331 ± 51 N/mm); however, this was not statistically significant (p = 0.051). CONCLUSION: This study confirms that suturing of the graft construct before interference screw fixation may increase ultimate failure load. However, an improvement of structural properties in response to cyclic loading with sub-maximal loads could not be confirmed. Clinicians using interference screw fixation may suture the graft to improve fixation strength; however, suturing does not appear to allow a more aggressive rehabilitation after surgery.

Peroneus Longus Split Versus Semitendinosus Tendon Autograft Size: A Cross-sectional Study.

BACKGROUND: The anterior half of the peroneus longus tendon (AHPLT) has been reported to be a suitable autograft for ligament reconstruction with low donor-site morbidity. However, clinical data on graft size are limited. PURPOSE: To determine (1) if there is any difference in size between the AHPLT and semitendinosus tendon (ST) and (2) whether anthropometric measurements can predict autograft size. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 128 consecutive patients scheduled for knee ligament reconstruction were prospectively enrolled. Patients were treated with AHPLT (50%) or ST (50%). Data included anthropometric measurements and intraoperatively recorded graft size. A Student t test was used to determine differences between the groups. Bivariate correlation coefficients and multivariate regression analyses were calculated to identify relationships between graft size and anthropometric measurements. RESULTS: The AHPLT and ST groups were equally distributed according to age, sex, height, weight, and body mass index (BMI). The quadrupled graft length for the AHPLT was 7.3 ± 0.6 cm as compared with 7.5 ± 0.7 cm for the ST (P < .05). The quadrupled graft diameter was 7.7 ± 0.8 mm for the AHPLT and 8.0 ± 0.7 mm for the ST (P < .05). Height had a moderate (r = 0.57) to high (r = 0.68) correlation with AHPLT and ST length, respectively (P < .01). Weight had a moderate correlation (r = 0.43) with AHPLT diameter (P < .01) but only a weak correlation (r = 0.19) with ST diameter (P > .05). A significant interaction effect of BMI and thigh circumference on ST graft diameter was found, which showed that the effect of thigh circumference on ST graft diameter decreased significantly as BMI increased (P < .05). This moderating effect of BMI could not be observed for the coefficient of shank circumference on AHPLT graft diameter (P > .05). CONCLUSION: (1) The peroneus longus split tendon provides a reliable autograft size for knee ligament reconstructions. It was prone to be slightly shorter and thinner than the ST. (2) Patient height was the strongest predictor for AHPLT and ST graft length. However, predicting graft diameter based on thigh or shank circumference was more challenging, with higher BMIs affecting the ability to predict ST more than AHPLT.

Tibial Slope on Conventional Lateral Radiographs in Anterior Cruciate Ligament-Injured and Intact Knees: Mean Value and Outliers.

BACKGROUND: An increased tibial slope (TS) has been identified as a risk factor for anterior cruciate ligament (ACL) injury and graft failure after ACL reconstruction. However, different imaging modalities are used to determine the TS, resulting in divergent values. Consequently, no reference values and no consensus on thresholds can be reached, which in turn is mandatory for indicating correction osteotomies when facing outlier TS. PURPOSE: To determine the mean values of the TS and the incidence of their outliers in large cohorts of patients with ACL-injured and noninjured knees and to determine the feasibility of measuring TS on conventional lateral radiographs (CLRs). STUDY DESIGN: Cross-sectional study; Level of evidence 3. METHODS: TS of ACL-injured knees (n = 1000, group A) and ACL-intact knees (n = 1000, group B) was measured by 3 experienced examiners. Medial TS was measured on CLRs using the technique of Dejour and Bonnin. Patients with radiographs with poor image quality, osteoarthritis, previous osteotomies, or nondigital radiographs were excluded. The intra- and interrater reliability was calculated using the intraclass correlation coefficient. RESULTS: The mean TS was significantly higher in group A than in group B (10.04°± 3° [range, 2°-22°] vs 9.02°± 2.9° [range, 1°-18°], respectively; P < .001). Significantly more participants in group A had TS larger than 12° (≥12°, 32.2% vs 19.8%, P < .001; ≥13°, 20.9% vs 11.1%, P < .001; ≥14°, 13.5% vs 5.7%, P < .001; ≥15°, 8% vs 2.7%, P < .001; ≥16°, 3.7% vs 1.4%, P = .0005), respectively. In contrast, significantly more participatns in group B had TS 8° or less (≤8°, 32.1% vs 42.7%, P < .001; ≤7°, 20% vs 30.9%, P < .001; ≤6°, 12.4% vs 19.8%, P < .001; ≤5°, 6.6% vs 12%, P = .0003; ≤4°, 2.8% vs 5.3%, P = .0045). The intraclass correlation coefficient revealed a good to excellent reliability throughout measurements. CONCLUSION: Median values for the TS were 9° for uninjured and 10° for ACL-injured knees on CLRs. Notwithstanding its statistical significance, this finding might be negligible in clinical practice. However, a significantly larger number of outliers were found in the ACL-injured group exceeding a TS of 12° and demonstrating an incremental proportion with increasing TS, serving as a potential threshold for correction osteotomy. Furthermore, CLRs in the largest cohort to date exhibited high reproducibility, proving the feasibility of CLRs as a routine measurement for TS.

Protocol for a Randomized Crossover Trial to Evaluate the Effect of Soft Brace and Rigid Orthosis on Performance and Readiness to Return to Sport Six Months Post-ACL-Reconstruction.

A randomized crossover trial was designed to investigate the influence of muscle activation and strength on functional stability/control of the knee joint, to determine whether bilateral imbalances still occur six months after successful anterior cruciate ligament reconstruction (ACLR), and to analyze whether the use of orthotic devices changes the activity onset of these muscles. Furthermore, conclusions on the feedforward and feedback mechanisms are highlighted. Therefore, twenty-eight patients will take part in a modified Back in Action (BIA) test battery at an average of six months after a primary unilateral ACLR, which used an autologous ipsilateral semitendinosus tendon graft. This includes double-leg and single-leg stability tests, double-leg and single-leg countermovement jumps, double-leg and single-leg drop jumps, a speedy jump test, and a quick feet test. During the tests, gluteus medius and semitendinosus muscle activity are analyzed using surface electromyography (sEMG). Motion analysis is conducted using Microsoft Azure DK and 3D force plates. The tests are performed while wearing knee rigid orthosis, soft brace, and with no aid, in random order. Additionally, the range of hip and knee motion and hip abductor muscle strength under isometric conditions are measured. Furthermore, patient-rated outcomes will be assessed.

Prevalence of cartilage lesions and early osteoarthritis in patients with patellar dislocation.

OBJECTIVES: Assessment of cartilage lesions and osteoarthritis (OA) of the patellofemoral joint in patients following lateral patellar dislocation using magnetic resonance imaging (MRI). METHODS: MR images of 129 knees (mean age 26 years, range 11-56) grouped as acute (A), recurrent (B), and chronic (C) dislocators were analysed regarding the prevalence and severity of patellofemoral cartilage lesions. Grades of OA were assessed using modified WORMS. RESULTS: In groups A, B, and C the prevalence of cartilage lesions was 71%, 82%, and 97%, respectively. Most lesions were located on the central patella in groups A and B (central 69% and 78%; medial 56% and 47%; lateral 31% and 42%), whereas group C revealed all regions affected (73%, 61%, and 67%). Of group A, 14% had mild OA and 64% of group B. Group C showed mild OA in 62% and moderate OA in 18%. Cartilage defect size and prevalence of OA was correlated with number of dislocations (r = 0.41 and r = 0.59; P < 0.001). CONCLUSIONS: Cartilage lesions and early OA are common after patellar dislocation and appear to increase with the frequency of dislocation. Both conditions should be considered when interpreting MRI in such patients, because of implications for treatment. KEY POINTS : • Cartilage lesions are very common after patellar dislocation. • The severity of cartilage lesions increases with number of dislocations. • Osteoarthritis is common after recurrent patellar dislocation, even in young patients. • Detecting cartilage lesions is important after patellar dislocation.

Sterilization with electron beam irradiation influences the biomechanical properties and the early remodeling of tendon allografts for reconstruction of the anterior cruciate ligament (ACL).

Although allografts for anterior cruciate ligament (ACL) replacement have shown advantages compared to autografts, their use is limited due to the risk of disease transmission and the limitations of available sterilization methods. Gamma sterilization has shown detrimental effects on graft properties at the high doses required for sufficient pathogen inactivation. In our previous in vitro study on human patellar tendon allografts, Electron beam (Ebeam) irradiation showed less detrimental effects compared to gamma sterilization (Hoburg et al. in Am J Sports Med 38(6):1134-1140, 2010). To investigate the biological healing and restoration of the mechanical properties of a 34 kGy Ebeam treated tendon allograft twenty-four sheep underwent ACL replacement with either a 34 kGy Ebeam treated allograft or a non-sterilized fresh frozen allograft. Biomechanical testing of stiffness, ultimate failure load and AP-laxity as well as histological analysis to investigate cell, vessel and myofibroblast-density were performed after 6 and 12 weeks. Native sheep ACL and hamstring tendons (HAT, each n = 9) served as controls. The results of a previous study analyzing the remodeling of fresh frozen allografts (n = 12) and autografts (Auto, n = 18) with the same study design were also included in the analysis. Statistics were performed using Mann-Whitney U test followed by Bonferroni-Holm correction. Results showed significantly decreased biomechanical properties during the early remodeling period in Ebeam treated grafts and this was accompanied with an increased remodeling activity. There was no recovery of biomechanical function from 6 to 12 weeks in this group in contrast to the results observed in fresh frozen allografts and autografts. Therefore, high dose Ebeam irradiation investigated in this paper cannot be recommended for soft tissue allograft sterilization.

Inactivation Effect of Standard and Fractionated Electron Beam Irradiation on Enveloped and Non-Enveloped Viruses in a Tendon Transplant Model.

BACKGROUND: For increasing allograft tendon safety in reconstructive surgery, an effective sterilization method achieving sterility assurance including viruses without impairing the grafts properties is needed. Fractionated Electron Beam (Ebeam) has shown promising in vitro results. The proof of sufficient virus inactivation is a central part of the process validation. METHODS: The Ebeam irradiation of the investigated viruses was performed in an optimized manner (oxygen content < 0.1%, -78 °C). Using principles of a tendon model the virus inactivation kinetics for HIV-2, HAV, pseudorabies virus (PRV) and porcine parvovirus (PPV) were calculated as TCID(50)/ml and D(10) value (kGy) for the fractionated (10 × 3.4 kGy) and the standard (1 × 34 kGy) Ebeam irradiation. RESULTS: All viruses showed comparable D(10) values for both Ebeam treatments. For sufficient virus titer reduction of 4 log(10) TCID(50)/ml, a dose of 34 kGy of the fractionated Ebeam irradiation was necessary in case of HIV-2, which was the most resistant virus investigated in this study. CONCLUSION: The fractionated and the standard Ebeam irradiation procedure revealed comparable and sufficient virus inactivation capacities. In combination with the known good biomechanical properties of fractionated Ebeam irradiated tendons, this method could be a safe and effective option for the terminal sterilization of soft tissue allografts.

Remodelling of human hamstring autografts after anterior cruciate ligament reconstruction.

PURPOSE: Histological analysis of the remodelling process of human hamstring tendon (HT) grafts after standardized anterior cruciate ligament reconstruction (ACLR) with an accelerated rehabilitation protocol. METHODS: Sixty-seven patients underwent retrieval of mid-substance biopsies after clinically successful hamstring autograft ACLR. Samples were allocated to one of three groups depending on the time point of retrieval: group 1 (6-12 months; n = 15), group 2 (13-24 months; n = 16) and group 3 (>24 months; n = 11). Biopsies from native HT (n = 17) and ACL (n = 8) served as controls. Cellular density, vascular density and myofibroblast density and collagen fibril alignment were analysed by haematoxylin-eosin, Masson-Goldner-Trichrom and immunohistochemical staining protocols. RESULTS: Compared with native HT (330.4/mm²), total cell number was increased in groups 1-3 (Group 1 = 482.0/mm² (P = 0.036); group 2 = 850.9/mm² (P = 0.005); and group 3 = 595.6/mm² (P = 0.043). There were no significant differences between the groups for vessel density. Myofibroblast density was higher in group 2 (199.6/mm²) compared with native HT (1.9/mm², P = 0.014). Collagen orientation was irregular up to 12 months. Thereafter, collagen orientation became more regular, adapting to, but not fully restoring, the appearance of the intact ACL. For the first 12 months, cells were predominantly ovoid. Ensuing cell morphology changed to spindle shaped in group 2 and predominantly narrow long cells over 24 months. CONCLUSION: Human hamstring grafts showed typical stages of graft remodelling, which was not complete up to 2 years after ACLR. The remodelling process in humans was prolonged compared with the results obtained in several animal studies. LEVEL OF EVIDENCE: Case-control study, Level III.

Systematic Review and Meta-Analysis of the Clinical Evidence on the Use of Autologous Matrix-Induced Chondrogenesis in the Knee.

OBJECTIVE: A systematic review and meta-analysis of Autologous Matrix-Induced Chondrogenesis (AMIC®) outcomes for grade III/IV chondral and osteochondral lesions of the knee treated with Chondro-Gide®. DESIGN: Studies with a minimum follow-up of 1 year providing clinical results of AMIC repair in the knee were included based on PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Methodological quality was assessed by the modified Coleman Methodology Score (mCMS). The meta-analysis was comparing pain VAS (Visual Analog Scale), Lysholm score, and IKDC score (International Knee Documentation Committee) between baseline and follow-up after 1 or 2 years and after >3 years. RESULTS: Twelve studies (375 patients) were included. The mCMS demonstrated a suboptimal study design (ranking between 52 and 80). The mean age was 36.2 years (14-70 years). The mean defect size was 4.24 cm2 (0.8-22 cm2). The results from the random effects model indicated a clinically significant (P < 0.05) improvement of pain VAS from baseline to follow-up at year 1 to 2 of -4.02(confidence interval -4.37; -3.67), still significant after 3 years. Lysholm score at year 1 or 2 improved significantly and remained highly significant after 3 years. IKDC score showed highly significant improvement of 32.61 between 1 and 2 years versus baseline values maintained after 3 years. CONCLUSIONS: The AMIC procedure significantly improved the clinical status and functional scoring versus preoperative values. Evidence was obtained in a non-selected patient population, corresponding to real-life treatment of knee chondral and osteochondral defects. The evidence is sufficient to recommend AMIC in this indication.