Total Hip Arthroplasty for Low-Grade Developmental Hip Dysplasia Changes the Ipsilateral Knee Alignment on the Axial and Coronal Planes.

BACKGROUND: There is a paucity of data regarding the post-operative influence of total hip arthroplasty (THA) on the axial and coronal alignments of the ipsilateral knee. A CT study was designed to assess the post-THA changes in axial and coronal knee alignments in low-grade dysplastic hips. METHODS: Forty Crowe I-II dysplastic hips in 37 patients were assessed: a pre-operative CT scan from the fourth lumbar vertebra to the tibial plateaus was compared to a similar post-operative CT scan performed after a minimum of 2 years after THA. RESULTS: THA implantation caused significant post-operative changes in terms of the rotation height (2 mm lowering; p = 0.003); center of rotation medialization (10 mm medialization; p < 0.001); femoral offset (11 mm increase; p < 0.001); femoral antetorsion (22° internal rotation; p < 0.001), and hip internal rotation (9° internal rotation; p < 0.001). The femoral axis angle deviated in the valgus (5.5° ± 1.1°, p < 0.001) and the mechanical lateral distal femoral angle deviated in the varus (86° ± 2.7°, p = 0.001). The pelvic-tibial alignment changed from 88.2° ± 11.7° to 96° ± 9.3° (p < 0.001). Patellar alignment was not influenced. CONCLUSIONS: In conclusion, THA imposes significant changes in low-grade dysplastic hips: all the modifications tend to neutralize the coronal alignment and, mostly, the rotational alignment, without substantial and durable variations of the patellofemoral joint. Large clinical trials should confirm whether radiological changes impact anterior knee pain and patellar stability.

Higher failure rate of secondary patellar resurfacing following bicompartmental knee arthroplasty.

INTRODUCTION: The role of secondary patellar resurfacing (SPR) in anterior knee pain (AKP) is still debated in literature. A regional arthroplasty registry was investigated, aiming to: (1) assess the survival rate of SPR; and (2) compare SPR to tricompartmental TKA. MATERIALS AND METHODS: The regional arthroplasty registry RIPO was investigated about all SPRs performed after bicompartmental arthroplasty. The survival rates and the reasons for revision were assessed as any other factor that could have influenced implants failure. SPR survivorship was compared to tricompartmental TKAs. RESULTS: 406 SPRs performed after bicompartmental arthroplasty were analyzed. The survival rates were 80.6% (CI 95% 75.9-84.5) at 5 years and 77.6% (CI 95% 72.4-82) at 7 years. Half of the SPRs was performed 0.9-2.4 years after the index bicompartmental arthroplasty. SPR achieved lower survival than tricompartmental TKA (80.6% vs 96.7%, p < 0.001), with an adjusted hazard ratio for failure of 5.5 (CI 95% 4.2-7.1, p < 0.001). SPRs performed within 2 years after primary implant had a significantly higher rates of failure when compared to tricompartmental TKA (HR: 6.4, CI 95% 4.8-8.4, p < 0.001). CONCLUSION: SPR after bicompartmental knee arthroplasty showed modest 5- and 7-year survival rates, worse than primary tricompartmental TKA. When SPRs are performed within 2 years after primary arthroplasty, a significant higher risk of failure should be expected, highlighting than appropriate pre-operative work-up and patient selection is crucial for SPR successful outcome. LEVEL OF EVIDENCE: III, therapeutic study.

ACL surgery: reasons for failure and management.

Despite the general success of anterior cruciate ligament reconstructions (ACL-R), there are still studies reporting a high failure rate. Orthopedic surgeons are therefore increasingly confronted with the treatment of ACL retears, which are often accompanied by other lesions, such as meniscus tears and cartilage damage and which, if overlooked, can lead to poor postoperative clinical outcomes. The literature shows a wide variety of causes for ACL-R failure. Main causes are further trauma and possible technical errors during surgery, among which the position of the femoral tunnel is thought to be one of the most important. A successful postoperative outcome after ACL-revision surgery requires good preoperative planning, including a thorough evaluation of patient's medical history, e.g. instability during daily or sports activity, increased general joint laxity, and hints for a low-grade infection. A careful clinical examination should be performed. Additionally, comprehensive imaging is necessary. Besides a magnetic resonance imaging, a CT scan is helpful to determine location of tunnel apertures and to analyze for tunnel enlargement. A lateral knee radiograph is helpful to determine the tibial slope. The range of surgical options for the treatment of ACL-R failure is broad today. Orthopedic surgeons and experts in Sports Medicine must deal with various possible associated injuries of the knee or unfavorable anatomical conditions for ACL-R. The aim of this review was to highlight predictors and reasons of failures of ACL-R as well as describe diagnostic procedures to individualize treatment strategies for improved outcome after revision ACL-R.

Total Knee Arthroplasty (TKA): When Do the Risks of TKA Overcome the Benefits? Double Risk of Failure in Patients up to 65 Years Old.

OBJECTIVE: The aim of this study was to document the survival rate in the middle-aged patient group up to 65 years old and to compare it with other age groups of patients undergoing total knee arthroplasty (TKA) for knee osteoarthritis (OA). DESIGN: The Register of Orthopaedic Prosthetic Implants (RIPO) regional registry was used to analyze the results of patients <80 years old affected by primary OA and treated with TKA from 2000 to 2019. The database was investigated according to the age group: younger than 50 years, 50-65 years, or 66-79 years, with the aim to estimate revision surgeries and implant survivorship. RESULTS: A total of 45,488 TKAs for primary OA were included in the analysis (M: 11,388; F: 27,846). The percentage of patients <65 years old increased from 13.5% to 24.8% between 2000 and 2019 (P < 0.0001). The survival analysis showed an overall influence of age on the implant revision rate (P < 0.0001), with an estimated survival rate of 78.7%, 89.4%, and 94.8% at 15 years in the 3 groups, respectively. Compared with the older-aged group, the relative risk of failure was 3.1 (95% confidence interval [CI] = 2.2-4.3; P < 0.001) higher in patients <50 years old and 1.8 (95% CI = 1.6-2.0; P < 0.001) higher in patients 50-65 years old. CONCLUSIONS: TKA use in the middle-aged patient population up to 65 years old increased significantly over time. These patients present a double risk of failure with respect to older patients. This is particularly important considering the increasing life expectancy and the emergence of new joint preserving strategies, which could postpone the need for TKA to an older age.

Gender related results in total knee arthroplasty: a 15-year evaluation of the Italian population.

INTRODUCTION: This study aimed to estimate separately in women and men the number of Total knee arthroplasty (TKA) procedures performed in Italy from 2001 to 2016, exploring specific gender-related characteristics and trends. MATERIALS AND METHODS: Data of this study were collected from the National Hospital Discharge Reports (NHDR) reported at the Italian Ministry of Health in the years between 2001 and 2016. The information included in this archive are the patient's sex, age, the year when the surgical procedure was performed and the length of the hospitalization. RESULTS: Between the years 2001 and 2016, a total of 848,863 TKAs have been performed in Italy. TKAs in women passed from 20,719 in 2001 to 49,320 in 2016 showing an increase of 138%, while TKAs in men passed from 6631 in 2001 to 23,601 in 2016 showing an increase of 256%. From the age of 50 onwards, there was a prevalence of procedures in women, from 63.2% in the 50-54 group to 85.7% in the 100 + group. Conversely, under the age of 50, there was a higher percentage of surgeries performed in males, 57.1% on a total of 16,434 TKA surgeries carried out in this age group. CONCLUSIONS: This study showed that TKA is growing and heavily affecting the female population (70.6% of all TKAs) between 2001 and 2016. However, under 50 years old there was a higher percentage of surgeries performed in males (57.1%). The average number of days of hospitalization in females was higher than in males.

Micro-fragmentation is a valid alternative to cell expansion and enzymatic digestion of adipose tissue for the treatment of knee osteoarthritis: a comparative preclinical study.

PURPOSE: The aim of this study was to compare three procedures to exploit adipose-derived cells for the treatment of osteoarthritis (OA) in a preclinical model, to understand their therapeutic potential and identify the most suitable approach for the clinical application. METHODS: Biological samples from adipose tissue, processed by mechanical micro-fragmentation (MF), enzymatic digestion (SVF) or cell expansion (ADSCs), were first characterized in vitro and then used in vivo in a surgically induced OA rabbit model: Group 1-control group (untreated 12 knees/saline 12 knees), Group 2-MF (24 knees), Group 3-SVF (24 knees), Group 4-ADSCs (24 knees). Macroscopic, histological, histomorphometric, immunohistochemical and blood and synovial fluid analyses were evaluated at 2 and 4 months from the treatments. RESULTS: Samples obtained by the three procedures yielded 85-95% of viable cells. In vivo assessments showed no significant side effects or inflammatory responses after the injection. The macroscopic Hanashi score did not show significant differences among treated groups and controls. The histopathological evaluation of synovial tissues showed lower signs of synovitis for MF, although the semiquantitative analysis (Krenn score) did not reach statistical significance. Instead, MF showed the best results both in terms of qualitative and semi-quantitative evaluations of articular cartilage, with a more uniform staining, a smoother surface and a significantly better Laverty score (p = 0.004). CONCLUSION: MF, SVF, and expanded ADSCs did not elicit significant local or systemic adverse reactions in this preclinical OA model. Among the different methods used to exploit the adipose tissue potential, MF showed the most promising findings in particular in terms of protection of the articular surface from the joint degenerative OA processes. LEVEL OF EVIDENCE: Preclinical animal study.

Isolated arthroscopic treatment of intra-articular pathologies in mild hip dysplasia: a short-term case control study.

PURPOSE: The aim is to compare the results of isolated hip arthroscopy in patients with borderline dysplasia with Lateral center edge angle (LCEA) between 18° and 25° with a control group of patients with normal LCEA (> 25°). METHODS: Fifty hip arthroscopies performed in 45 patients were retrospectively evaluated. Exclusion criteria were: age > 40, hip arthritis > grade 2 according to Tonnis classification, femoral head avascular necrosis, pediatric's orthopaedics conditions and true dysplasia with LCEA < 18°.Two groups were identified: group A with 15 hips with LCEA between 25° and 18° and Group control B made of 35 hips with LCEA > 25°. RESULTS: The groups were homogeneous for demography and pre-operative WOMAC and HOOS. Osteoplasty for CAM were performed in 100% of patients in both groups, only in 12 hips (34.4%) in group B we had both femoral and acetabular osteoplasty. Labral repair was performed in 86% of patients in group A, in 60% of patients in group B, capsular plication in 93% of group A, in 5% of case of group B. WOMAC and HOOS statically significant improved in both groups at final follow-up (24 months). No cases in both groups required conversion to total hip arthroplasty. Clinical outcomes of study group were comparable to the control group. CONCLUSION: Even if the present small series is not conclusive, we suggest isolated arthroscopic management of patients with FAI and LCEA between 18° and 25°, but capsular plication and careful labral management are strongly recommended. LEVEL OF EVIDENCE: Level IV.

Bone Regeneration in Load-Bearing Segmental Defects, Guided by Biomorphic, Hierarchically Structured Apatitic Scaffold.

The regeneration of load-bearing segmental bone defects remains a significant clinical problem in orthopedics, mainly due to the lack of scaffolds with composition and 3D porous structure effective in guiding and sustaining new bone formation and vascularization in large bone defects. In the present study, biomorphic calcium phosphate bone scaffolds (GreenBone™) featuring osteon-mimicking, hierarchically organized, 3D porous structure and lamellar nano-architecture were implanted in a critical cortical defect in sheep and compared with allograft. Two different types of scaffolds were tested: one made of ion-doped hydroxyapatite/ß-tricalcium-phosphate (GB-1) and other made of undoped hydroxyapatite only (GB-2). X-ray diffraction patterns of GB-1 and GB-2 confirmed that both scaffolds were made of hydroxyapatite, with a minor amount of ß-TCP in GB-1. The chemical composition analysis, obtained by ICP-OES spectrometer, highlighted the carbonation extent and the presence of small amounts of Mg and Sr as doping ions in GB-1. SEM micrographs showed the channel-like wide open porosity of the biomorphic scaffolds and the typical architecture of internal channel walls, characterized by a cell structure mimicking the natural parenchyma of the rattan wood used as a template for the scaffold fabrication. Both GB-1 and GB-2 scaffolds show very similar porosity extent and 3D organization, as also revealed by mercury intrusion porosimetry. Comparing the two scaffolds, GB-1 showed slightly higher fracture strength, as well as improved stability at the stress plateau. In comparison to allograft, at the follow-up time of 6 months, both GB-1 and GB-2 scaffolds showed higher new bone formation and quality of regenerated bone (trabecular thickness, number, and separation). In addition, higher osteoid surface (OS/BS), osteoid thickness (OS.Th), osteoblast surface (Ob.S/BS), vessels/microvessels numbers, as well as substantial osteoclast-mediated implant resorption were observed. The highest values in OS.Th and Ob. S/BS parameters were found in GB-1 scaffold. Finally, Bone Mineralization Index of new bone within scaffolds, as determined by micro-indentation, showed a significantly higher microhardness for GB-1 scaffold in comparison to GB-2. These findings suggested that the biomorphic calcium phosphate scaffolds were able to promote regeneration of load-bearing segmental bone defects in a clinically relevant scenario, which still represents one of the greatest challenges in orthopedics nowadays.

Cell-Free Biomimetic Osteochondral Scaffold for the Treatment of Knee Lesions: Clinical and Imaging Results at 10-Year Follow-up.

BACKGROUND: Cell-free devices have been introduced to restore osteochondral defects, avoiding the limitations of cell-based procedures. Among these, an osteochondral scaffold made of type I collagen and hydroxyapatite has been investigated with promising results up to medium-term follow-up. However, the clinical and imaging results over time still need to be documented. PURPOSE: To evaluate the clinical outcome and tissue maturation at long-term follow-up after the implantation of the osteochondral scaffold. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 24 patients (7 women, 17 men; age, 36 ± 9.5 years) underwent surgical implantation of the osteochondral scaffold and were prospectively evaluated before surgery, at 2-, 5-, and 10-year follow-up. The mean defect size was 2.9 ± 1.4 cm2. Patients were evaluated using the International Knee Documentation Committee (IKDC) subjective and objective scores, and the activity level was documented with the Tegner score. Magnetic resonance imaging (MRI) evaluation involved the use of the magnetic resonance observation of cartilage repair tissue score combined with 5 more variables focused on the bone layer. RESULTS: A statistically significant improvement of all clinical scores was documented from the baseline to the final evaluation. The IKDC subjective score improved from the preoperative level to 2 years (41 ± 13.2 and 77.1 ± 14.6, respectively) (P < .0005), with stable results up to 10 years (77.4 ± 19.4). The IKDC objective score changed from 52% of normal and nearly normal knees before the treatment to 84% at 10 years (P < .0005). Tegner sports activity at the final evaluation (3.8 ± 1.7) was higher compared with the preoperative level (1.6 ± 1.1; P < .05), but it remained significantly lower compared with the preinjury level (5.5 ± 2.6; P < .05). Treatment failed in 1 patient. Persisting graft alterations were observed on MRI scans, although without correlating with the clinical outcome. CONCLUSION: The regenerative potential of this scaffold is limited, as demonstrated by the signal alterations persisting over time on MRI scans. On the other hand, the clinical improvement was significant and stable over time both in terms of subjective and objective outcomes, including activity level, with overall good results.

Polyurethane scaffold implants for partial meniscus lesions: delayed intervention leads to an inferior outcome.

PURPOSE: The purpose of this study was to assess the clinical outcomes of the implantation of an aliphatic polyurethane scaffold for the treatment of partial loss of meniscal tissue at a mean follow-up of 36 months. METHODS: A retrospective review on prospectively collected data was performed on patients who underwent implantation of an aliphatic polyurethane-based synthetic meniscal scaffold. Patients were evaluated for demographics data, lesion and implant characteristics (sizing, type and number of meniscal sutures), previous and combined surgeries and complications. Clinical parameters were rated using NRS, IKDC subjective, Lysholm, KOOS, and Tegner activity score, both preoperatively and at final follow-up. RESULTS: Sixty-seven patients were evaluated at a mean follow-up of 36 months (48 M and 19 F; mean age 40.8 ± 10.6 years; mean BMI 25.4 ± 4.3). The scaffold was implanted on the medial side in 54 cases, and on the lateral one in 13. Forty-seven patients had undergone previous surgical treatment at the same knee and 45 required combined surgical procedures. All evaluated scores improved significantly from the baseline. Among possible prognostic factors, a delayed scaffold implantation had lower post-operative clinical scores: IKDC subjective (P = 0.049), KOOS Sport (P = 0.044), KOOS total (p = 0.011), and Tegner (P = 0.03) scores at follow-up. CONCLUSIONS: The polyurethane meniscal scaffold implantation led to a significant clinical benefit in a large number of patients. A delayed intervention correlated with worse results. LEVEL OF EVIDENCE: IV.

Short-Term Teriparatide for Bone Marrow Edema Secondary to Complex Regional Pain Syndrome: Case Reports on Efficacy After Two Years of Follow-Up.

Bone marrow edema secondary to chronic pain syndrome after knee trauma is a disabling condition that presents with localized pain, allodynia, edema, decreased range of motion and osteopenia. The management includes a variety of medications and rehabilitation. The treatment of refractory diseases is challenging for most physicians. We present two cases of refractory bone edema secondary to complex regional pain syndrome that were successfully treated with a short-term regimen of teriparatide (TPT), a biosynthetic analogue (PTH 1-34) of the human parathormone. The rapid and sustained pain reduction with recovery of knee function for two years following administration of TPT demonstrated its potential for the treatment of bone edema due to complex regional pain syndrome.

Meniscus Scaffolds for Partial Meniscus Defects.

The meniscus is a crucial player in knee joint homeostasis. Loss of meniscus tissue can result in early onset of clinical symptoms like pain and loss of function, and structural degeneration of the articular cartilage. In case of a symptomatic segmental defect of the medial or lateral meniscus, different innovative options using biological or synthetic scaffolds are now available to regenerate meniscuslike tissue, with the aim of allowing a satisfactory clinical improvement to patients. However, the role of any of these procedures in terms of chondroprotection is questionable, and the overall outcomes in the long term still can be improved.

Regenerative Features of Adipose Tissue for Osteoarthritis Treatment in a Rabbit Model: Enzymatic Digestion Versus Mechanical Disruption.

Evaluating cell migration after cell-based treatment is important for several disorders, including osteoarthritis (OA), as it might influence the clinical outcome. This research explores migrating expanded-adipose stromal cells (ASCs) and adipose niches after enzymatic and mechanical processes. Bilateral anterior cruciate ligament transection induced a mild grade of OA at eight weeks in adult male New Zealand rabbits. ASCs, enzymatic stromal vascular fraction (SVF), and micro fragmented adipose tissue (MFAT) were intra-articularly injected in the knee joint. Assessments of cell viability and expression of specific markers, including CD-163 wound-healing macrophages, were done. Cell migration was explored through labelling with PKH26 dye at 7 and 30 days alongside co-localization analyses for CD-146. All cells showed good viability and high percentages of CD-90 and CD-146. CD-163 was significantly higher in MFAT compared to SVF. Distinct migratory potential and time-dependent effects were observed among cell-based treatments. At day 7, both ASCs and SVF migrated towards synovium, whereas for MFAT versus cartilage, a different migration pattern was noticed at day 30. The long-term distinct cell migration of ASCs, SVF, and MFAT open interesting clinical insights on their potential use for OA treatment. Moreover, the highest expression of CD-163 in MFAT, rather than SVF, might have an important role in directly mediating cartilage tissue repair responses.

A Composite Chitosan-Reinforced Scaffold Fails to Provide Osteochondral Regeneration.

Several biomaterials have recently been developed to address the challenge of osteochondral regeneration. Among these, chitosan holds promises both for cartilage and bone healing. The aim of this in vivo study was to evaluate the regeneration potential of a novel hybrid magnesium-doped hydroxyapatite (MgHA), collagen, chitosan-based scaffold, which was tested in a sheep model to ascertain its osteochondral regenerative potential, and in a rabbit model to further evaluate its ability to regenerate bone tissue. Macroscopic, microtomography, histology, histomorphometry, and immunohistochemical analysis were performed. In the sheep model, all analyses did not show significant differences compared to untreated defects (p > 0.05), with no evidence of cartilage and subchondral bone regeneration. In the rabbit model, this bone scaffold provided less ability to enhance tissue healing compared with a commercial bone scaffold. Moreover, persistence of scaffold material and absence of integration with connective tissue around the scaffolds were observed. These results raised some concerns about the osteochondral use of this chitosan composite scaffold, especially for the bone layer. Further studies are needed to explore the best formulation of chitosan-reinforced composites for osteochondral treatment.

Osteochondritis Dissecans of the Knee - Conservative Treatment Strategies: A Systematic Review.

OBJECTIVE: Osteochondritis dissecans (OCD) lesions are a relevant problem that affects the long-term prognosis of young patients. The purpose of this study was to analyze the evidence on potential and indications of nonsurgical treatment strategies for knee OCD. DESIGN: The search was conducted on 3 medical electronic databases according to PRISMA guidelines, including reports of any level of evidence dealing with the conservative management of knee OCD. Of 1688 identified records, 55 full-text articles were screened: 27 studies met the inclusion criteria, for a total of 908 knees, and were used for the analysis. RESULTS: No high-level studies were found: 24 articles were case series and 3 case reports, reporting on different treatments summarized in (1) restriction of physical activity, (2) physiokinesitherapy and muscle-strengthening exercises, (3) physical instrumental therapies, (4) limitation of weightbearing, and (5) immobilization. The analysis showed an overall healing rate of 61.4%, with large variability (10.4%-95.8%). A conservative treatment based on restriction of sport and strenuous activities seems a favorable approach, possibly combined with physiokinesitherapy. Negative prognostic factors were also identified: larger lesion size, more severe lesion stages, older age and skeletal maturity, discoid meniscus, and clinical presentation with swelling or locking. CONCLUSIONS: The literature on conservative treatments for knee OCD is scarce. Among different non-surgical treatment options, strenuous activity restriction seems a favorable approach, whereas there is no evidence that physical instrumental therapy, immobilization, or weightbearing limitation could be beneficial. However, further studies are needed to improve treatment potential and indications for the conservative management of knee OCD.

Cell-Free Biomimetic Osteochondral Scaffold: Implantation Technique.

This 1-stage cell-free scaffold-based technique is indicated for the treatment of full-thickness chondral and osteochondral lesions in the knee, regardless of the lesion size. The aim of the procedure is restoration of the osteochondral unit while avoiding the issues of donor site morbidity and those related to cell management. DESCRIPTION: The surgical technique is simple and can be performed as a 1-stage procedure. The lesion site is visualized through a standard knee medial or lateral parapatellar arthrotomy. The defect is prepared by excision of the injured cartilage and subchondral bone to ensure adequate bone-marrow blood flow and to create a squared, regularly shaped lodging for the device. The scaffold is then shaped and sized according to the dimensions of the prepared lesion site and implanted by press-fitting or with addition of fibrin glue. Finally, the complete range of motion is tested to assess the stability of the implant before and after releasing the tourniquet. ALTERNATIVES: Nonsurgical alternatives have been reported to include nonpharmacological modalities, such as dietary supplements, and pharmacological therapies as well as physical therapies and novel biological procedures involving injections of various substances1. There are several surgical alternatives, including among others microfracture, mosaicplasty, osteochondral allograft, and total knee arthroplasty, depending primarily on the disease stage and etiology as well as the specific patient conditions2,3. RATIONALE: This cell-free device is engineered in 3 layers to mimic the structure and composition of the osteochondral unit in order to guide resident cells toward an ordered regeneration of both bone and cartilage layers, providing a better quality of regenerated articular surface. The treatment approach offers a useful alternative to current procedures in the field of osteochondral lesions, in particular for young and middle-aged patients affected by symptomatic defects in which subchondral bone is likely involved. The advantages of this scaffold include the ability to perform a 1-stage surgical procedure, off-the-shelf availability, a straightforward surgical technique, and lower costs compared with cell-based regenerative options. Furthermore, in contrast to some more traditional treatments, it can be used for large lesions.

Novel alginate biphasic scaffold for osteochondral regeneration: an in vivo evaluation in rabbit and sheep models.

Current therapeutic strategies for osteochondral restoration showed a limited regenerative potential. In fact, to promote the growth of articular cartilage and subchondral bone is a real challenge, due to the different functional and anatomical properties. To this purpose, alginate is a promising biomaterial for a scaffold-based approach, claiming optimal biocompatibility and good chondrogenic potential. A previously developed mineralized alginate scaffold was investigated in terms of the ability to support osteochondral regeneration both in a large and medium size animal model. The results were evaluated macroscopically and by microtomography, histology, histomorphometry, and immunohistochemical analysis. No evidence of adverse or inflammatory reactions was observed in both models, but limited subchondral bone formation was present, together with a slow scaffold resorption time.The implantation of this biphasic alginate scaffold provided partial osteochondral regeneration in the animal model. Further studies are needed to evaluate possible improvement in terms of osteochondral tissue regeneration for this biomaterial.

Association between incision technique for hamstring tendon harvest in anterior cruciate ligament reconstruction and the risk of injury to the infra-patellar branch of the saphenous nerve: a meta-analysis.

PURPOSE: To determine how the incision technique for hamstring tendon (HT) harvest in anterior cruciate ligament (ACL) reconstruction affects the risk of injury to the IPBSN and clinical outcome. METHODS: A systematic literature search of the MEDLINE/Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL) and EBSCOhost electronic databases and clinicaltrials.gov for unpublished studies was performed to identify comparative studies investigating injury to the IPBSN after HT ACL reconstruction by comparing at least two different incision techniques. Data were extracted for the number of patients with evidence of any neurologic deficit corresponding to injury to the IPBSN, area of sensory deficit, the Lysholm score and patient satisfaction. The mean difference (MD) in study outcome between incision groups was assessed. The relative risk (RR) and the number needed to treat (NNT) were calculated. The Chi-square and Higgins' I2 tests were applied to test heterogeneity. Data were pooled using a Mantel-Haenszel random-effects model if the statistical heterogeneity was > 50% and a fixed-effects model if the statistical heterogeneity was < 50%. The risk of bias was evaluated according to the Cochrane Database questionnaire and the quality of evidence was graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines. RESULTS: A total of eight studies (three randomized controlled trials (RCTs) and five comparative studies) were included, of which six compared vertical and oblique incisions, one horizontal and vertical incisions, and one compared all three techniques. HT harvest was performed through a vertical incision in 329 patients, through an oblique incision in 195 patients and through a horizontal incision in 151 patients. Considering the meta-analysis of the RCTs, the performance of a vertical incision significantly increased the risk of causing IPBSN deficiency compared with both oblique and horizontal incision [RR 1.65 (CI 1.10-2.49, p = 0.02) and RR 2.45 (CI 1.73-3.47, p < 0.0001), respectively]. A significantly larger area of sensory deficit was found with vertical incisions compared with oblique ones, with an MD of 22.91 cm2 (95% CI 7.73-38.08; p = 0.04). No significant differences were found between the incision techniques in relation to patient-reported outcomes. The same trend was obtained after the performing a meta-analysis of all eight included studies. The quality of evidence in this meta-analysis was determined as "low" to "moderate", mostly due to inadequate methods of randomization and high heterogeneity among the included studies. CONCLUSION: The performance of a vertical incision to harvest HTs for ACL reconstruction significantly increased the risk of iatrogenic injury to the IPBSN compared with both oblique and horizontal incisions. LEVEL OF EVIDENCE: Level I-III, meta-analysis of comparative studies.

Treatment of Knee Osteochondritis Dissecans With a Cell-Free Biomimetic Osteochondral Scaffold: Clinical and Imaging Findings at Midterm Follow-up.

BACKGROUND: Osteochondritis dissecans (OCD) is a developmental condition of subchondral bone that may result in secondary separation and instability of the overlying articular cartilage, which in turn may lead to degeneration of the overall joint and early osteoarthritis. Biphasic scaffolds have been developed to address defects of the entire osteochondral unit by reproducing the different biological and functional requirements and guiding the growth of both bone and cartilage. PURPOSE: To evaluate midterm clinical and imaging results after cell-free osteochondral scaffold implantation for the treatment of knee OCD. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-seven patients (8 women, 19 men; mean age, 25.5 ± 7.7 years) were treated for knee OCD, with International Cartilage Repair Society (ICRS) grade 3 to 4 lesions with a mean size of 3.4 ± 2.2 cm2 (range, 1.5-12 cm2), and prospectively evaluated for up to 5 years using the ICRS classification system and the Tegner score. Eighteen patients underwent magnetic resonance imaging (MRI) at 24 and 60 months of follow-up, and the graft was evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) score for the cartilage layer, while a specific score was used for subchondral bone. RESULTS: All patients significantly improved their clinical scores at each follow-up until their final evaluation. The mean International Knee Documentation Committee (IKDC) subjective score improved from 48.4 ± 17.8 to 82.2 ± 12.2 at 2 years ( P < .0005), and it then remained stable for up to 5 years postoperatively (90.1 ± 12.0). The mean Tegner score increased from 2.4 ± 1.7 preoperatively to 4.4 ± 1.6 at 2 years ( P = .001), with a further increase up to 5.0 ± 1.7 at 5 years of follow-up ( P < .0005 vs preoperatively), reaching almost the preinjury level (5.7 ± 2.2). The MOCART score showed stable results between 24 and 60 months, whereas the subchondral bone status significantly improved over time. No correlation was found between MRI findings and clinical outcomes. CONCLUSION: This 1-step cell-free scaffold implantation procedure showed good and stable results for up to 60 months of follow-up for the treatment of knee OCD. MRI showed abnormalities, in particular at the subchondral bone level, but there was an overall improvement of features over time. No correlation was found between imaging and clinical findings.