Primary Proximal ACL Repair: A Biomechanical Evaluation of Different Arthroscopic Suture Configurations.

Purpose: Several suture techniques have been described in the past for direct ACL repair with poor healing capacity and a high re-rupture rate. Therefore, we investigated a refixation technique for acute primary proximal ACL repair. The purpose of this study is to compare the biomechanical properties of different suture configurations using a knotless anchor. Methods: In this study, 35 fresh-frozen porcine knees underwent proximal ACL refixation. First, in 10 porcine femora, the biomechanical properties of the knotless anchor, without the ligament attached, were tested. Then, three different suture configurations were evaluated to reattach the remaining ACL. Using a material testing machine, the structural properties were evaluated for cyclic loading followed by loading to failure. Results: The ultimate failure load of the knotless anchor was 198, 76 N ± 23, 4 N significantly higher than all of the tested ACL suture configurations. Comparing the different configurations, the modified Kessler-Bunnell suture showed significant superior ultimate failure load, with 81, 2 N ± 15, 6 N compared to the twofold and single sutures (50, 5 N ± 14 N and 37, 5 ± 3, 8 N). In cyclic loading, there was no significant difference noted for the different configurations in terms of stiffness and elongation. Conclusions: The results of this in vitro study show that when performing ACL suture using a knotless anchor, a modified Kessler-Bunnell suture provides superior biomechanical properties than a single and a twofold suture. Within this construct, no failure at the bone-anchor interface was seen. Clinical relevance: Since primary suture repair techniques of ACL tears have been abandoned because of inconsistent results, ACL reconstruction remains the gold standard of treating ACL tears. However, with the latest improvements in surgical techniques, instrumentation, hardware and imaging, primary ACL suture repair might be a treatment option for a select group of patients. By establishing an arthroscopic technique in which proximal ACL avulsion can be reattached, the original ACL can be preserved by using a knotless anchor and a threefold suture configuration. Nevertheless, this technique provides an inferior ultimate failure load compared to graft techniques, so a careful rehabilitation program must be followed if using this technique in vivo.

LOQTEQ® VA Periprosthetic Plate-A New Concept for Bicortical Screw Fixation in Periprosthetic Fractures: A Technical Note.

Internal fixation using angle stable plates is the treatment standard in periprosthetic fractures around stable implants. To provide instant postoperative full weight-bearing, bicortical screw fixation is advisable but often surgically demanding. This work presents the first clinical results of the LOQTEQ® VA Periprosthetic Plate (aap Implantate AG, Berlin, Germany), a new plate system to simplify screw placement around implants. This plate system uses insertable hinges that allow for variable angle screw anchorage. Data of 26 patients with a mean age of 80 years and a mean follow-up of 13.9 months were retrospectively collected. Patients were clinically and radiologically examined. Bony union was achieved in 14 out of 15 patients with no signs of non-union or implant loosening. One patient, however, presented with implant failure. Clinical scores demonstrated acceptable results. Since the hinge plates are easy to apply, the first results are promising.

Peri- and Interprosthetic Femoral Fractures-Current Concepts and New Developments for Internal Fixation.

Treatment of peri- and interprosthetic fractures represents a challenge in orthopedic trauma surgery. Multiple factors such as osteoporosis, polymedication and comorbidities impede therapy and the rehabilitation of this difficult fracture entity. This article summarizes current concepts and highlights new developments for the internal fixation of periprosthetic fractures. Since the elderly are unable to follow partial weight bearing, stable solutions are required. Therefore, a high primary stability is necessary. Numerous options, such as new angular stable plate systems with additional options for variable angle screw positioning, already exist and are in the process of being further improved. Lately, individually produced custom-made implants are offering interesting alternatives to treat periprosthetic fractures.

Germany has a high demand in meniscal allograft transplantation but is subject to health economic and legal challenges: a survey of the German Knee Society.

PURPOSE: To determine the current status and demand of meniscal allograft transplantation (MAT) in Germany among members of the German Knee Society (= Deutsche Kniegesellschaft; DKG). METHODS: An online survey was conducted between May 2021 and June 2021 and sent to all members of the DKG. The survey questionnaire consisted of 19 questions to determine the demand and technical aspects of MAT among the participants and to identify areas of improvement in MAT in Germany. RESULTS: Overall, 152 participants, 136 (89.5%) from Germany, 8 (5.3%) from Switzerland, 6 (4.0%) from Austria, and 2 (1.3%) from other countries completed the online survey, with the majority working in non-academic institutions. According to the regulations of the DKG, 87 (57.2%) participants were board certified as specialized knee surgeons and 97 (63.8%) worked primarily in the field of orthopedic sports medicine. MAT was considered clinically necessary in Germany by 139 (91.5%) participants. Patient age (83.6%), post-meniscectomy syndrome in isolated lateral (79.6%) and medial (71.7%) meniscus deficiency, and functional and athletic demands (43.4%) were the most important determinants to consider MAT in patients. Participants reported that reimbursement (82.9%), jurisdiction over the use of donor grafts (77.6%), and the availability of meniscal allografts (76.3%) are the main challenges in performing MAT in Germany. The most frequently used meniscal allograft types by 54 (35.5%) participants who had already performed MAT were fresh-frozen grafts (56.6%), peracetic acid-ethanol sterilized grafts (35.9%), and cryopreserved grafts (7.6%). Participants reported to perform suture-only fixation more often than bone block fixation for both medial (73.6% vs. 22.6%) and lateral (69.8% vs. 24.5%) MAT. CONCLUSION: More than 90% of the responding members of the DKG indicated that MAT is a clinically important and valuable procedure in Germany. Reimbursement, jurisdiction over the use of donor grafts, and the availability of meniscal allografts should be improved. This survey is intended to support future efforts to facilitate MAT in daily clinical practice in Germany. LEVEL OF EVIDENCE: Level V.

[Posterior meniscus root tears]. / Posteriore Wurzelverletzungen der Menisken.

Meniscus root tears are radial tears in the region of the posterior insertion zones. Medial root injuries usually occur in individuals > 50 years of age without adequate trauma and are associated with obesity and varus deformities. The root lesion leads to a loss of ring tension, which results in extrusion of the meniscus and a strong increase in joint pressure that is biomechanically equivalent to a complete meniscectomy. When indicating arthroscopic transosseous refixation of the medial root lesion, factors such as accompanying cartilage damage, osteoarthritis, obesity and varus deformity must be taken into account. Injuries to the root of the lateral meniscus are mostly observed in younger patients in combination with a rupture of the anterior cruciate ligament. Arthroscopic transosseous refixation in combination with cruciate ligament surgery is therefore also recommended for type I and type II lesions. In summary, both the medial and the lateral root lesions of the menisci are injuries with high biomechanical relevance.

Effect of serum and platelet-rich plasma on human early or advanced degenerative meniscus cells.

PURPOSE: The purpose of this in vitro study was to evaluate the migratory, proliferating, and extracellular matrix (ECM) forming effect of human serum (HS) and platelet-rich plasma (PRP) on meniscus cells derived from human knees with early or advanced degenerative changes. MATERIALS AND METHODS: Medial menisci from knees with early degenerative changes (n = 5; mean Kellgren score of 1) undergoing arthroscopic meniscal surgery and advanced degenerative changes (n = 5; mean Kellgren score of 4) undergoing total knee replacement were collected. Cell migration and proliferation upon stimulation with HS and PRP were assessed by migration and proliferation assays. Induction of meniscal ECM was evaluated histologically by hematoxylin and eosin, collagen type I, and alcian blue staining and by gene expression analysis of meniscus-related genes in pellets that have been stimulated with 10% HS or 5% PRP. RESULTS: Meniscal cells from knees with early and advanced degenerative changes were significantly attracted by 2.5%-30% PRP or 10% HS. Cell proliferation was significantly increased upon stimulation with 10% HS or 5% PRP. Both cell groups showed the formation of a well-structured, meniscus-like ECM after stimulation with 10% HS, whereas stimulation with 5% PRP led to inhomogeneous, more fibrous ECM. Stimulation with 10% HS showed a significant induction of aggrecan and COMP, while 5% PRP showed no inducing effect. CONCLUSIONS: Only stimulation with HS showed the formation of meniscal ECM as well as cell proliferating and migratory effects on meniscal cells derived from knees with early or advanced degenerative changes. Thus, we suggest that the selected stimulating factor itself and not the status of the knee may primarily affect repair processes. HS may have a potential to augment in meniscal repair procedures.

Acute Proximal Anterior Cruciate Ligament Tears: Outcomes After Arthroscopic Suture Anchor Repair Versus Anatomic Single-Bundle Reconstruction.

PURPOSE: To compare clinical and radiologic results of primary anterior cruciate ligament (ACL) suture anchor repair and microfracturing with anatomic ACL single-bundle reconstruction in patients with acute proximal ACL avulsion tears. METHODS: Between January 2010 and December 2013, 420 patients underwent ACL treatment. Forty-one patients were included in this study. The inclusion criteria were as follows: unilateral acute proximal ACL rupture, concomitant meniscus lesions, no previous knee ligament surgery, and no additional ligament injuries or absence of ligament injury of the contralateral knee. Preoperative magnetic resonance imaging confirming a proximal avulsion tear of the ACL was required. Patients had to undergo surgical treatment within 6 weeks after injury. Follow-up examination included Lachman and pivot-shift testing, KT-1000 measurement, and the International Knee Documentation Committee score. RESULTS: At a mean follow-up of 28 months (range, 24 to 31 month), 20 patients in each group were available. A mean KT-1000 arthrometer result of less than 3 mm indicated stability in all patients (P = .269). Three patients had a 1+ Lachman test (P = .072) and 4 patients had a 1+ pivot-shift test in the ACL repair group (P = .342). The International Knee Documentation Committee score results did not differ significantly (P > .99), but there was a significant correlation between poor results and failure rate (P = .001) in the refixation group. The failure rate was 15% in the ACL refixation group and 0% in the reconstruction group (P = .231). Magnetic resonance imaging confirmed homogeneous signal and proper ACL position in 100% of patients in the control group and 86% in the ACL repair group. CONCLUSIONS: Proximal refixation of the ACL using knotless suture anchors and microfracturing restores knee stability and results in comparable functional outcomes to a control group treated with single-bundle ACL reconstruction. The results suggest that refixation of the ACL is a feasible treatment option in selected patients. LEVEL OF EVIDENCE: Level III, case-control study.

Open wedge high tibial osteotomy (HTO) versus mobile bearing unicondylar medial joint replacement: five years results.

INTRODUCTION: Aim of this study was to compare clinical results after open wedge HTO (OW-HTO and medial unicondylar joint replacement (UKA) in patients aged between 55 and 65. MATERIALS AND METHODS: Fifty-four patients aged between 55 and 65 years with medial OA and varus malalignement who had been treated by either OW-HTO or UKA could be included. Minimum follow up was 5 years. The HSS knee score and the KOOS were used to evaluate clinical outcome. RESULTS: There was no difference in the revision rate, the HSS knee score and the KOOS subscales Sports/Rec and ADL between the OW-HTO and UKA group. However, the KOOS subscales pain, Symptoms and QoL were significantly better in the UKA group compared to the OW-HTO. CONCLUSIONS: The results of this study showed that 5 years after surgery patients after UKA had less residual pain and symptoms than patients after UKA. These advantages might result in a higher quality of life.

Effect of Human Serum and 2 Different Types of Platelet Concentrates on Human Meniscus Cell Migration, Proliferation, and Matrix Formation.

PURPOSE: To evaluate the effect of 10% human serum (HS), 5% platelet-rich plasma (PRP), and 5% autologous conditioned plasma (ACP) on migration, proliferation, and extracellular matrix (ECM) synthesis of human meniscus cells. METHODS: Cell migration and proliferation on stimulation with HS, PRP, and ACP were assessed by chemotaxis assays and measurement of genomic DNA content. Meniscus cells were cultivated in pellets stimulated with 10% HS, 5% PRP, or 5% ACP. Meniscal ECM formation was evaluated by histochemical staining of collagen type I, type II, and proteoglycans and by analysis of fibrochondrocyte marker gene expression. RESULTS: Human meniscus cells were significantly attracted by all 3 blood-derived products (10% HS and 5% ACP: P = .0001, 5% PRP: P = .0002). Cell proliferation at day 9 was significantly increased on stimulation with 10% HS (P = .0001) and 5% PRP (P = .0002) compared with 5% ACP and controls. Meniscus cell pellet cultures showed the formation of a well-structured meniscal ECM with deposition of collagen type I, type II, and proteoglycans on stimulation with 10% HS, whereas 5% PRP or 5% ACP resulted in the formation of an inhomogeneous and more fibrous ECM. Stimulation with 10% HS and 5% ACP showed a significant induction of fibrochondrocyte marker genes such as aggrecan (HS: P = .0002, ACP: P = .0147), cartilage oligomeric matrix protein (HS: P = .0002, ACP: P = .0005), and biglycan (HS: P = .0002, ACP: P = .0003), whereas PRP showed no inducing effect. CONCLUSIONS: Among all tested blood-derived products, only stimulation with HS showed the formation of a meniscal ECM as well as positive cell proliferating and migrating effects in vitro. Regarding a potential biological repair of nonvascular meniscus lesions, our results may point toward the use of HS as a beneficial augment in regenerative meniscus repair approaches. CLINICAL RELEVANCE: Our findings may suggest that HS might be a beneficial augment for meniscus repair.

Platelet-Rich Plasma Preparation Types Show Impact on Chondrogenic Differentiation, Migration, and Proliferation of Human Subchondral Mesenchymal Progenitor Cells.

PURPOSE: To evaluate the chondrogenic potential of platelet concentrates on human subchondral mesenchymal progenitor cells (MPCs) as assessed by histomorphometric analysis of proteoglycans and type II collagen. Furthermore, the migratory and proliferative effect of platelet concentrates were assessed. METHODS: Platelet-rich plasma (PRP) was prepared using preparation kits (Autologous Conditioned Plasma [ACP] Kit [Arthrex, Naples, FL]; Regen ACR-C Kit [Regen Lab, Le Mont-Sur-Lausanne, Switzerland]; and Dr.PRP Kit [Rmedica, Seoul, Republic of Korea]) by apheresis (PRP-A) and by centrifugation (PRP-C). In contrast to clinical application, freeze-and-thaw cycles were subsequently performed to activate platelets and to prevent medium coagulation by residual fibrinogen in vitro. MPCs were harvested from the cortico-spongious bone of femoral heads. Chondrogenic differentiation of MPCs was induced in high-density pellet cultures and evaluated by histochemical staining of typical cartilage matrix components. Migration of MPCs was assessed using a chemotaxis assay, and proliferation activity was measured by DNA content. RESULTS: MPCs cultured in the presence of 5% ACP, Regen, or Dr.PRP formed fibrous tissue, whereas MPCs stimulated with 5% PRP-A or PRP-C developed compact and dense cartilaginous tissue rich in type II collagen and proteoglycans. All platelet concentrates significantly (ACP, P = .00041; Regen, P = .00029; Dr.PRP, P = .00051; PRP-A, P < .0001; and PRP-C, P < .0001) stimulated migration of MPCs. All platelet concentrates but one (Dr.PRP, P = .63) showed a proliferative effect on MPCs, as shown by significant increases (ACP, P = .027; Regen, P = .0029; PRP-A, P = .00021; and PRP-C, P = .00069) in DNA content. CONCLUSIONS: Platelet concentrates obtained by different preparation methods exhibit different potentials to stimulate chondrogenic differentiation, migration, and proliferation of MPCs. Platelet concentrates obtained by commercially available preparation kits failed to induce chondrogenic differentiation of MPCs, whereas highly standardized PRP preparations did induce such differentiation. These findings suggest differing outcomes with PRP treatment in stem cell-based cartilage repair. CLINICAL RELEVANCE: Our findings may help to explain the variability of results in studies examining the use of PRP clinically.

Minimally Invasive Coracoclavicular Ligament Reconstruction With a Flip-Button Technique (MINAR): Clinical and Radiological Midterm Results.

BACKGROUND: Acromioclavicular (AC) joint dislocation is a frequent injury in sports. HYPOTHESIS: A minimally invasive flip-button technique, MINAR (minimally invasive acromioclavicular joint reconstruction), will achieve good clinical and radiographic results in the surgical treatment of high-grade AC joint dislocations. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: In this study, 96 patients with AC joint dislocation grades III through V and minimally invasive flip-button repair were identified. Radiographic assessment was performed by use of the Alexander view and by anteroposterior stress radiograph. Clinical outcomes were assessed with the Constant and Taft scores. Factors that influenced outcomes, such as age, time from trauma to surgery, and degree of dislocation, were evaluated. RESULTS: Of the 96 patients, 83 (86.4%; 3 women and 80 men) were able to participate in clinical and radiographic follow-up. The average age of the participants was 39 years (range, 17-80 years). At a mean follow-up of 39 months (range, 12-78 months), clinical assessment revealed excellent results with a mean Constant score of 94.7 (range, 61-100). Clinical and radiological assessment using the Taft score also showed excellent results, with a mean score of 10.8 (range, 3-12). The mean time period from trauma to surgery was 6 days (range, 0-22 days), and mean duration of surgery was 48 minutes (range, 24-98 minutes). Nine patients (10.8%) underwent revision surgery due to recurrent dislocation (n = 8) or wound infection (n = 1). Radiological assessment showed that 18 patients had sustained a loss of reduction defined as subluxation of 50% of the clavicle shaft width in the vertical plane. However, there was no significant correlation (P = .254) with clinical outcome. Patient age was a relevant factor influencing outcome, as significantly higher outcome values were detected for younger patients (P = .024). No significant influence was shown for the time period from trauma to surgery (P = .336) or degree of dislocation after trauma (P = .987). CONCLUSION: The MINAR technique is a safe procedure and achieves good to excellent clinical and radiographic results in the surgical treatment of high-grade AC joint dislocations. Despite the simplicity of this technique, the surgeon has to overcome the learning curve to minimize the risk of recurrent dislocation.

Midterm results following medial closed wedge distal femoral osteotomy stabilized with a locking internal fixation device.

PURPOSE: Aim of this study was to evaluate the subjective and radiological outcome and to evaluate the complications of a medial closing wedge osteotomy at the femur for lateral osteoarthritis with genu valgum. METHODS: Twenty-three patients with grade III to IV cartilage damage and valgus knee alignment were treated with medial closing wedge osteotomy at the distal femur. The osteotomy was stabilized with an internal plate fixator. Age varied between 25 and 55 years (mean 47 years). One patient was lost to final follow-up. RESULTS: After 3.5 years, all Knee Osteoarthritis Outcome Score (KOOS) subitems increased significantly. There was no significant difference in the subgroup analysis of KOOS subitems for patients with and without microfracture or age (>50 vs. <50 years). There were no perioperative complications. One patient had an overcorrection. All, but one osteotomy, showed stable bone healing. There was a loss of correction due to delayed bone healing in one case. Possible explanations for this complication were injury of the lateral cortex or smoking. This case required revision with bone graft and an additional lateral plate. In no case, a conversion to an endoprosthesis was necessary. CONCLUSION: The femoral medial closing wedge osteotomy is a surgical method for improving symptoms of lateral osteoarthritis in the valgus knee. LEVEL OF EVIDENCE: IV.

The biomechanical effect of a lateral meniscus posterior root tear with and without damage to the meniscofemoral ligament: efficacy of different repair techniques.

PURPOSE: To evaluate the effect of the meniscofemoral ligament (MFL) in maintaining lateral-compartment contact pressures after injury to the posterior root of the lateral meniscus, and to measure the ability to restore intra-articular loads to normal by repairing the posterior root to the tibia after transection of the posterior root and the MFL. METHODS: Ten human cadaveric knee joints were axially loaded to 100 N. A digital pressure sensor measured the contact pressure in the lateral compartment. Five different conditions were tested: intact, after release of the posterior root of the lateral meniscus, after transection of the MFL along with release of the posterior root, refixation of the posterior root of the lateral meniscus to the tibia using an anatomic transosseous tunnel, and refixation of the root of the lateral meniscus using a tibial anterior cruciate ligament (ACL) tunnel. RESULTS: After transection of the posterior lateral meniscus root, the contact pressure did not increase significantly. The additional transection of the MFL led to a significant increase in the contact pressure. Anatomic fixation of the meniscus posterior horn reduced the femorotibial pressure to nearly pre-sectioning values. The reattachment of the meniscus posterior horn through a tibial ACL tunnel was equivalent to an anatomic fixation. CONCLUSIONS: In the case of a root tear of the lateral meniscus, the MFL maintains meniscus function and stabilizes the pressure in the lateral compartment. A complete detachment of the posterior meniscus horn (MFL and root tear) leads to an increase in the intra-articular pressure. A root repair normalizes the pressure down to normal values. The tibial ACL tunnel is suitable to perform the repair and to lead out the suture. CLINICAL RELEVANCE: In the case of a complete detachment of the meniscus posterior horn, fixation of the posterior root is necessary to restore the meniscus function and to guarantee an equal pressure distribution in the lateral compartment. It can be combined with an ACL reconstruction.

Tunnel widening after anatomic double-bundle and mid-position single-bundle anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare the amount of postoperative bone tunnel enlargement after anatomic double-bundle (DB) and single-bundle (SB) anterior cruciate ligament (ACL) reconstruction 6 to 8 months after surgery. METHODS: Twenty-one consecutive patients undergoing anatomic 4-tunnel DB ACL reconstruction and 24 patients undergoing anatomic 2-tunnel SB ACL reconstruction were included in this study. In both groups a hybrid fixation technique with interference screw and extracortical fixation at the tibia and an extracortical fixation technique at the femur were used. Magnetic resonance imaging was performed on the second postoperative day and at a mean of 8 months' follow-up (range, 6.8 to 8.3 months) to assess intraoperative and postoperative bone tunnel enlargement. Tunnel widening was determined in different planes by digitally measuring the diameters of the bone tunnels. Tunnel position was measured and classified according to Harner et al. (femoral) and Stäubli et al. and Petersen et al. (tibial). RESULTS: Magnetic resonance imaging showed that all bone tunnels were anatomically placed within the area of the original ACL insertion zone. Compared with the intraoperative drill diameter, we observed only a slight increase in tunnel diameter in both groups on the second postoperative day. At 8 months postoperatively, significant bone tunnel widening occurred in all bone tunnels (P < .001). However, no significant differences were found between tunnel enlargement in the DB group and tunnel enlargement in the SB group (P > .05), either on the tibial side or on the femoral side. In 2 cases tibial tunnel communication was noted at follow-up. CONCLUSIONS: With the use of anatomic SB and DB ACL reconstruction techniques, the results of bone tunnel enlargement were comparable; no significant difference was observed between the tibial and femoral tunnels. LEVEL OF EVIDENCE: Level III, prospective comparative study.

Technique of anatomical footprint reconstruction of the ACL with oval tunnels and medial portal aimers.

PURPOSE: The purpose of this article was to demonstrate an anterior cruciate ligament (ACL) reconstruction technique using oval tunnels. Aim of this single bundle technique is to fit the footprint anatomy of the ACL as closely as possible. TECHNIQUE AND PATIENTS: The presented technique is a single bundle technique using a semitendinosus graft. For femoral tunnel placement, a specific medial portal aimer (Karl Storz, Tuttlingen, Germany) is used. Aiming and drilling of the femoral tunnel are performed via the medial portal. Oval tunnels are created by stepwise dilatation with ovally shaped dilatators. The position of the femoral tunnel is visualized and controlled with the arthroscope via the medial portal. For the tibial tunnel placement, a specific aimer was used as well. With this technique, 24 patients were operated and all intra- and postoperative complications were analyzed prospectively. The tunnel position was documented postoperatively by CT scan. RESULTS: There were no significant intra- and postoperative complications associated with the oval tunnel technique. The postoperative 3D CT scan revealed that all femoral and tibial tunnels were located within the area of the anatomical ACL insertions. CONCLUSIONS: This article presents an ACL reconstruction technique using oval dilatators and medial portal aimers to create oval tunnels. These oval tunnels match the insertion site anatomy much closer than round tunnels do. LEVEL OF EVIDENCE: Level IV, case series.