Aims. Implantation of ultra-purified alginate (UPAL) gel is safe and effective in animal osteochondral defect models. This study aimed to examine the applicability of UPAL gel implantation to acellular therapy in humans with cartilage injury. Methods. A total of 12 patients (12 knees) with symptomatic, post-traumatic, full-thickness cartilage lesions (1.0 to 4.0 cm. 2. ) were included in this study. UPAL gel was implanted into chondral defects after performing bone marrow stimulation technique, and assessed for up to three years postoperatively. The primary outcomes were the feasibility and safety of the procedure. The secondary outcomes were self-assessed clinical scores, arthroscopic scores, tissue biopsies, and MRI-based estimations. Results. No obvious adverse events related to UPAL gel implantation were observed. Self-assessed clinical scores, including pain, symptoms, activities of daily living, sports activity, and quality of life, were improved significantly at three years after surgery. Defect filling was confirmed using second-look arthroscopy at 72 weeks. Significantly improved MRI scores were observed from 12 to 144 weeks postoperatively. Histological examination of biopsy specimens obtained at 72 weeks after implantation revealed an extracellular matrix rich in glycosaminoglycan and type II collagen in the reparative tissue. Histological assessment yielded a mean overall International Cartilage Regeneration & Joint Preservation Society II score of 69.1 points (SD 10.4; 50 to 80). Conclusion. This study provides evidence supporting the safety of acellular UPAL gel implantation in facilitating cartilage repair. Despite being a single-arm study, it demonstrated the efficacy of UPAL gel implantation, suggesting it is an easy-to-use, one-step method of cartilage tissue repair circumventing the need to harvest donor cells. Cite this article: Bone Joint J 2023;105-B(8):880–887

Chondral defects in the knee have cartilage biomechanical differences due to defect size and orientation. This study examines how the tibiofemoral contact pressure is affected by increasing full-thickness chondral defect size on the medial and lateral condyle at full extension. Isolated full-thickness, square chondral defects increasing from 0.09cm. 2. to 1.0cm. 2. were created sequentially on the medial and lateral femoral condyles of six human cadaveric knees with intact ligaments and menisci. Chondral defects were created 1.0cm from the femoral notch posteriorly. The knees were fixed to a uniaxial load frame and loaded from 0N to 600N at full extension. Contact pressures between the femoral and tibial condyles were measured using pressure mapping sensors. The peak contact pressure was defined as the highest value in the 2.54mm. 2. area around the defect. The location of the peak contact pressure was determined relative to the centre of the defect. Peak contact pressure was significantly different between (4.30MPa) 0.09cm. 2. and (6.91MPa) 1.0cm. 2. defects (p=0.04) on the medial condyle. On the lateral condyle, post-hoc analysis showed differences in contact pressures between (3.63MPa) 0.09cm. 2. and (5.81MPa) 1.0cm. 2. defect sizes (p=0.02). The location of the stress point shifted from being posteromedial (67% of knees) to anterolateral (83%) after reaching a 0.49cm. 2. defect size (p < 0.01) in the medial condyle. Conversely, the location of the peak contact pressure point moved from being anterolateral (50%) to a posterolateral (67%) location in defect sizes greater than 0.49cm. 2. (p < 0.01). Changes in contact area redistribution and cartilage stress from 0.49cm. 2. to 1.0cm. 2. impact adjacent cartilage integrity. The location of the maximum stress point also varied with larger defects. This study suggests that size cutoffs exist earlier in the natural history of chondral defects, as small as 0.49cm. 2. , than previously studied, suggesting a lower threshold for intervention

Background. Partial humeral head resurfacing using a stemless implant is a bone-conserving option in treatment of focal chondral defects. We report our experience using the Arthrosurface HemiCAP® device. Methods. This is a retrospective study of patients with focal chondral defects of the humeral head, treated with partial resurfacing arthroplasty, with a minimum follow-up of 2 years. Mean patient age was 45.4 years (range 27–76). Patients were analyzed in 2 groups: those who underwent HemiCAP for an isolated humeral head defect, and those who had HemiCAP combined with biologic resurfacing of concomitant glenoid disease. Results. 39 patients met inclusion criteria, 5 of whom had concomitant biologic glenoid resurfacing. 24 of 34 shoulders (70.6%) with HemiCAP alone demonstrated functional improvement and decreased pain. Mean forward flexion showed some improvement from 131 degrees pre-operatively to 158 degrees post-operatively (p=0.004). Mean Subjective Shoulder Value improved from 35.0% to 83.6% (p< 0.001). ASES score improved from 29.8 to 77.7(p< 0.001). However, follow-up radiographs showed progression of glenoid disease in 20.6%(7 shoulders). 5 shoulders(14.7%) failed and were revised: 3 to total shoulder arthroplasty, 1 to hemiarthroplasty, and 1 patient underwent glenohumeral fusion. 5 (14.7%) had some pain at latest follow-up but were pursuing a course of conservative management. In the group with associated biologic glenoid resurfacing, all 5 patients had ongoing pain and progression of glenohumeral arthritis requiring revision or glenohumeral fusion. Conclusion. While 70% of patients with an isolated humeral head chondral defect had significant improvement in pain and function after HemiCAP, the outcomes were not superior to those published for complete humeral head resurfacing, or for stemmed prostheses. HemiCAP was not successful for patients with concomitant glenoid disease. Results for these patients were inferior to those published for total shoulder arthroplasty, and ultimately all were revised to a stemmed prosthesis or fused

Articular cartilage repair remains a challenge in orthopedic surgery, as none of the current clinical therapies can regenerate the functional hyaline cartilage tissue. In this study, we proposed a one-step surgery strategy that uses autologous bone marrow mesenchymal stem cells (MSCs) embedded in type II collagen (Col-II) gels to repair the full thickness chondral defects in minipig models. Briefly, 8 mm full thickness chondral defects were created in both knees separately, one knee received Col-II + MSCs transplantation, while the untreated knee served as control. At 1, 3 and 6 months postoperatively, the animals were sacrificed, regenerated tissue was evaluated by magnetic resonance imaging, macro- and microscopic observation, and histological analysis. Results showed that regenerated tissue in Col-II + MSCs transplantation group exhibited significantly better structure compared with that in control group, in terms of cell distribution, smoothness of surface, adjacent tissue integration, Col-II content, structure of calcified layer and subchondral bone. With the regeneration of hyaline-like cartilage tissue, this one step strategy has the potential to be translated into clinical application

Background. Cartilage lesions in chronic lateral ligament deficiency are common with the incidence rates mentioned in the previous literature up to 30%. However, other intra-articular pathologies in the unstable ankle have received little attention. Anterolateral impingement associated with synovitis and scarring is a less recognised feature in the treatment of chronic instability. The aim of our study was to ascertain the incidence of chondral and anterolateral impingement lesions in the symptomatic lateral ligament complex deficiency. Methods. We performed a retrospective study of all consecutive patients who underwent modified Brostrom repair for symptomatic recurrent instability of the ankle. All patients underwent a MRI scan prior to surgery. Arthroscopy was performed in all the patients before lateral ligament reconstruction. Seventy seven patients with 78 ankles were included in the study. Patients who had previous ankle surgery or inflammatory arthropathy were excluded. Data was obtained from clinical and radiological records. Arthroscopic findings were recorded in detail during the surgery. Results. The mean age was 29.8 years (Range 18.2–58 yrs). There were 44 females and 34 males in the study. The incidence of chondral lesions were 11.5% (9 out of 78 ankles). The commonest site for chondral defect was the anteromedial talar dome. The incidence of anterolateral impingement which required arthroscopic debridement was 48.7 %(38 ankles). A further 10 ankles revealed non-specific synovitis and scarring which was debrided. The sensitivity and specificity of the MRI scans in the assessment of chondral lesions is 91% and 100%. Conclusion. The incidence of chondral lesions in chronic ankle instability is lower than previously published literature. However, soft tissue impingement lesions have a much higher incidence and require debridement. Arthroscopic examination and debridement of impingement prior to lateral ligament reconstruction of the ankle is quintessential in the management of chronic anterolateral instability

Aims. Our objective was to conduct a systematic review and meta-analysis, to establish whether differences arise in clinical outcomes between autologous and synthetic bone grafts in the operative management of tibial plateau fractures. Methods. A structured search of MEDLINE, EMBASE, the online archives of Bone & Joint Publishing, and CENTRAL databases from inception until 28 July 2021 was performed. Randomized, controlled, clinical trials that compared autologous and synthetic bone grafts in tibial plateau fractures were included. Preclinical studies, clinical studies in paediatric patients, pathological fractures, fracture nonunion, or chondral defects were excluded. Outcome data were assessed using the Risk of Bias 2 (ROB2) framework and synthesized in random-effect meta-analysis. The Preferred Reported Items for Systematic Review and Meta-Analyses guidance was followed throughout. Results. Six studies involving 353 fractures were identified from 3,078 records. Following ROB2 assessment, five studies (representing 338 fractures) were appropriate for meta-analysis. Primary outcomes showed non-significant reductions in articular depression at immediate postoperative (mean difference -0.45 mm, p = 0.25, 95%confidence interval (CI) -1.21 to 0.31, I. 2. = 0%) and long-term (> six months, standard mean difference -0.56, p = 0.09, 95% CI -1.20 to 0.08, I. 2. = 73%) follow-up in synthetic bone grafts. Secondary outcomes included mechanical alignment, limb functionality, and defect site pain at long-term follow-up, perioperative blood loss, duration of surgery, occurrence of surgical site infections, and secondary surgery. Mean blood loss was lower (90.08 ml, p < 0.001, 95% CI 41.49 to 138.67) and surgery was shorter (16.17 minutes, p = 0.04, 95% CI 0.39 to 31.94) in synthetic treatment groups. All other secondary measures were statistically comparable. Conclusion. All studies reported similar methodologies and patient populations; however, imprecision may have arisen through performance variation. These findings supersede previous literature and indicate that, despite perceived biological advantages, autologous bone grafting does not demonstrate superiority to synthetic grafts. When selecting a void filler, surgeons should consider patient comorbidity, environmental and societal factors in provision, and perioperative and postoperative care provision. Cite this article: Bone Jt Open 2022;3(3):218–228

3D printing and Bioprinting technologies are becoming increasingly popular in surgery to provide a solution for the regeneration of healthy tissues. The aim of our project is the regeneration of articular cartilage via bioprinting means, to manage isolated chondral defects. Chrondrogenic hydrogel (chondrogel: GelMa + TGF-b3 and BMP6) was prepared and sterilised in our lab following our standard protocols. Human adipose-derived mesenchymal stem cells were harvested from the infrapatellar fat pad of patients undergoing total knee joint replacements and incorporated in the hydrogel according to our published protocols. The chondrogenic properties of the chondrogel have been tested (histology, immunohistochemistry, PCR, immunofluorescence, gene analysis and 2. nd. harmonic generation microscopy) in vitro and in an ex-vivo model of human articular defect and compared with standard culture systems where the growth factors are added to the media at repeated intervals. The in-vitro analysis showed that the formation of hyaline cartilage pellet was comparable between the two strategies, with a similar metabolic activity of the cells. These results have been confirmed in the ex-vivo model: hyaline-like cartilage was observed within the chondral defect in both the chondrogel group and the control group after 28 days in culture. The use of bioprinting techniques in vivo requires the ability of stem cells to access growth factors directly in the environment they are in, as opposed to in vitro techniques where these factors are provided externally at recurrent intervals. This study showed the successful strategy of incorporating chondrogenic growth factors for the formation of hyaline-like cartilage in vitro and in an ex-vivo model of chondral loss. The incorporation of chondrogenic growth factors in a hydrogel is a possible strategy for articular cartilage regeneration

To evaluate the short-term clinical outcomes of patients treated arthroscopically with chitin-based scaffolding for acetabular chondral defects in conjunction with microfracture compared to microfracture alone. This study is a retrospective analysis of prospectively collected data. A review of charts was performed (2014–2016) on all patients who underwent hip arthroscopy and had microfracture +/− scaffolding for acetabular chondral defects, intraoperative details (lesion size, grade, labral repair/reconstruction) and postoperative complications were recorded with a minimum follow-up of 2 years. Clinical outcomes were assessed by analysing iHOT and HOS scores which were obtained pre-operatively, at six months, one year and two years post-surgery. Plain radiographs were assessed for hip osteoarthritis by Kellgren & Lawrence grading. A total of 60 patients (microfracture=25, scaffolding=35) were included. Patients had a mean age of 36.2 years at the time of the index operation. There were no major adverse events of deep vein 36.2 years at the time of the index operation. There were no major adverse events of deep vein thrombosis, blood vessel or nerve damage, hemarthrosis or device related adverse events in both groups. Two patients were readmitted due to pain as a result of an inflammatory reaction in the scaffolding group. Both treatments of microfracture and scaffolding showed significant improvement in outcome score (iHOT) (p < 0 .001) when compared postoperative to preoperative. Both the arthroscopic treatment of chondral acetabular defects with chitin based scaffolding and microfracture demonstrated significant improvement from their pre-operative outcomes

Purpose: A pilot study to assess whether intra-articular injections of autologous marrow-derived stem cells (MSC) and hyaluronic acid (HA) will result in a better quality of cartilage regeneration after subchondral drillings into surgically created full-thickness chondral defects. Methods: 15 male goats were subjected to full-thickness chondral defects followed by subchondral drillings. The goats were divided into three groups: Group A, no injection (control group); Group B, a weekly intra-articular injection of HA for three consecutive weeks; Group C, a weekly intra-articular injection of autologous MSC in combination with HA for up to three consecutive weeks. The intra-articular injections were given one week after surgery. Group C goats underwent bilateral iliac crest bone marrow aspiration during surgery. The bone marrow aspirates were centrifuged and bone marrow cell suspension were then divided into vials and cryo-preserved. Prior to usage, the bone marrow cells were thawed and prepared for intra-articular injections. The repaired chondral defects were visually inspected and histologically examined at week 24. Results: In groups A and B goats, the defects showed repair with mainly fibrous tissues. Chondral defects in Group C goats showed better repair of tissues with some specimens showing mainly hyaline cartilage as compared to the other groups. Conclusion: Intra-articular injections of autologous MSC in combination with HA following subchondral drillings into chondral defects result in a better quality of neochondrogenesis. Preliminary results from on-going human clinical trials provide similar evidence of articular cartilage regeneration following subchondral drillings into chondral defects followed by post-operative intra-articular injections of autologous peripheral blood stem cells (PBSCs) in combination with HA

Since June 2002 15 hip autologous chondrocyte transplantations were arthroscopically performed for both acetabular roof and femoral head chondral defects. 15 Patients affected by chondral defect in the hip joint were treated with autologous chondrocyte transplantation. The mean follow up was 13.8 months (range 16 – 12 months) and the chondral defect was classified as 3rd – 4th degree, according to the Outerbridge’s classification. The defects were located on the acetabular roof in 12 cases, on the femoral head in 2 cases and on booths articular surfaces in 1 case. 9 patients were female and 6 male. The mean age was 40.7 years (from 52 to 22).In all cases the procedure was arthroscopically performed. A Bioseed C tissue was employed as a scaffold for chondrocytes, cultured in a tridimentional shape. A group of untreated 15 patients, matched for chondral defect degree, sex distribution and mean age was selected as control. All the Patients of both groups were pre and post operatively evaluated with the Harris Hip Score (HHS). Patients treated with hip autologous chondrocyte transplantation significantly improved after surgery (mean pre-op HHS 51.3; mean post-op HHS 85.3) compared with the untreated group (mean pre-op HHS 52.1; mean post-op HHS 64.5). Worst results were obtained in Patients affected by chondral defect located on the femoral head and when the joint space was reduced. Hip arthroscopy steel represent a new approach for treatment of hip’s disorders. Chondral defects of the hip can be treated with autologous chondrocyte transplantation, performed by hip arthroscopy. This study demonstrates the efficacy of this procedure compared with untreated patients

Femoroacetabular impingement is a prearthritic deformity frequently associated with early chondral damage. Several techniques exist for restoring larger cartilage defects. While AMIC proved to be an effective treatment in knee and ankle, there are only short-term data available in hip. This study aimed to investigate the mid-term clinical outcome of patients with chondral lesions treated by AMIC and evaluate the quality of repair tissue via MRI. This retrospective, single center study includes 18 patients undergoing surgical hip dislocation for FAI between 2013 and 2016. Inclusion criteria were: cam or pincer-type FAI, femoral or acetabular chondral lesions > 1 cm. 2. , (IRCS III-IV). Due to exclusion criteria and loss-to-follow-up 9 patients (10 hips) could be included. Patient reported outcome measures included Oxford Hip Score (OHS) & Core Outcome Measure Index (COMI)). MRIs were evaluated using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. None of the patients underwent revision surgery except screw removals from the greater trochanter. Followup data indicate a satisfactory to good hip function at 5 years: PROMS improved from pre- to postop at 5 years: OHS from 38.1 to 43.4, COMI from to 1.8 and UCLA from 4 to 8.1 respectively. MOCART score was 67.5 postoperatively. Subgrouping showed slightly better results for acetabular defects (Ø 69.4) compared femoral defects (Ø 60). Based on the reported mid-term results, we consider AMIC as a valuable treatment option for larger chondral defects of the hip

Articular cartilage (AC) and subchondral bone (SB) are intimately intertwined, forming a complex unit called the AC-SB interface. Our recent studies have shown that cartilage and bone marrow are connected by a three-dimensional network of microchannels (i.e. cartilage-bone marrow microchannel connector; CMMC), which differ microarchitecturally in number, size and morphology depending on the maturation stage of the bone and the region of the joint. However, the pathological significance of CMMC is largely unknown. Here, we quantitatively assessed how CMMC microarchitecture relates to cartilage condition and regional differences in early idiopathic osteoarthritis (OA). Two groups of cadaveric female human femoral heads (intact cartilage vs early cartilage lesions) were identified and biopsy-based high-resolution micro-CT imaging was used. Subchondral bone (SB) thickness, CMMC number, maximum and minimum CMMC size, and CMMC morphology were quantified and compared between the two groups. The effect of joint region and cartilage condition on each dependent variable was examined. The number and morphology of CMMCs were influenced by the region of the joint, but not by the cartilage condition. On the other hand, the minimum and maximum CMMC size was modified by both joint location and cartilage condition. The smallest CMMCs were consistently found in the load bearing region (LBR) of the joint. Compared to healthy subjects, the size of the microchannels was increased in early OA, most notably in the non-load bearing region (NLBR) and the peripheral rim (PR) of the femoral head. In addition, subchondral bone thinning was observed in early OA as a localized event associated with areas of partial chondral defect. Our data suggest an enlargement of the SB microchannel network and a collective structural deterioration of the SB in early idiopathic OA

Abstract. Background. Osteochondral allograft (OCA) transplantation is a clinically and cost-effective option for symptomatic cartilage defects. In 2017 we initiated a program for OCA transplantation for complex chondral and osteochondral defects as a UK tertiary referral centre. Aim. To characterise the complications, re-operation rate, graft survivorship and clinical outcomes of knee OCA transplantation. Methodology. Analysis of a prospectively maintained database of patients treated with primary OCA transplantation from 2017 to 2021 with a minimum of one-year follow-up. Patient reported outcome measures (PROMs), complications, re-operations and failures were evaluated. Results. 37 patients with 37 knee OCA procedures were included (mean age 31.6 years [16–49 years]). Mean BMI 26.6 kg/m2 (19.1–35.9 kg/m2). The mean chondral defect size was 3cm2 (1.2–7.3 cm2). Mean duration of follow-up was 3.1 years (1–5.3 years). 16 patients underwent meniscal allograft transplantation (MAT), 6 underwent osteotomy and 4 underwent ligament reconstruction as concurrent procedures. Significant improvements in mean PROMs were noted at 12 months. 16 patients had reoperations of which 5 had more than one surgery. Of these patients 6 were related to OCA (mainly debridement and revision OCA in one patient), and the remainder were related to additional procedures including removal of plate in 2 patients. The overall failure rate was 1 in 37 patients (3%). Conclusions. Early experience of OCA as a treatment option for complex chondral and osteochondral lesions in the knee shows satisfactory results. The reoperation rate is high but at mean follow-up of 3.1 years the survival rate was 97%

Introduction. Autologous Chondrocyte Implantation (ACI) is an effective surgical treatment for chondral defects. ACI involves arthrotomy for cell implantation. We describe the development of an intra-articular injection of cultured MSC, progressing from in-vitro analysis, through animal model, clinical and radiological outcome at five years follow up. Materials and Methods. We prospectively investigated sixteen patients with symptomatic ICRS grade III and IV lesions. These patients underwent cartilage repair using cultured mesenchymal stem cell injections and are followed up for five years. Results. Statistically significant clinical improvement was noted by two years and was sustained for five years of the study. At five years, mean Lysholm score was 80, compared to 44 pre-operatively. Symptomatic KOOS improved to 88 from 55. Subjective IKD Calso showed improvement from 42 to 76. On morphological MRI MOCART score was 76 and qualitative MRI showed the mean T2relaxation-times were 28 and 31 for their pair tissue and native cartilage respectively. Discussion. Cultured MSC provides a good number of uncommitted stem cells to the previously prepared chondral defects of the knee by “homing on” phenomenon. Cultured cells, suspended in serum can be delivered by an intra-articular injection. Conclusion. Use of cultured MSC is less invasive, avoids complications associated with arthrotomy, compared to ACI technique. Good clinical results were found to be sustained at five years of follow-up with a regenerate that appears like surrounding native cartilage. The use of Cultured Mesenchymal Stem Cells (MSC) has represented a promising treatment to restore the articular cartilage

Our objective was to conduct a systematic review and meta-analysis, comparing differences in clinical outcomes between either autologous or synthetic bone grafts in the operative management of tibial plateau fractures: a traumatic pattern of injury, associated with poor long-term functional prognosis. A structured search of MEDLINE, EMBASE, The Bone & Joint and CENTRAL databases from inception until 07/28/2021 was performed. Randomised, controlled, clinical trials that compared autologous and synthetic bone grafts in tibial plateau fractures were included. Preclinical studies, clinical studies in paediatric patients, pathological fractures, fracture non-union or chondral defects were excluded. Outcome data was assessed using the Risk of Bias 2 (ROB2) framework and synthesised in random-effect meta-analysis. Preferred Reported Items for Systematic Review and Meta-Analysis guidance was followed throughout. Six comparable studies involving 352 patients were identified from 3,078 records. Following ROB2 assessment, five studies (337 patients) were eligible for meta-analysis. Within these studies, more complex tibia plateau fracture patterns (Schatzker IV-VI) were predominant. Primary outcomes showed non-significant reductions in articular depression at immediate postoperative (mean difference −0.45mm, p=0.25, 95% confidence interval (95%CI): −1.21-0.31mm, I. 2. =0%) and long-term (>6 months, standard mean difference −0.56, p=0.09, 95%CI: −1.20-0.08, I. 2. =73%) follow-up in synthetic bone grafts. Secondary outcomes included mechanical alignment, limb functionality, defect site pain, occurrence of surgical site infections, secondary surgery, perioperative blood loss, and duration of surgery. Blood loss was lower (90.08ml, p<0.001, 95%CI: 41.49-138.67ml, I. 2. =0%) and surgery was shorter (16.17minutes, p=0.04, 95%CI: 0.39-31.94minutes, I. 2. =63%) in synthetic treatment groups. All other secondary measures were statistically comparable. Our findings supersede previous literature, demonstrating that synthetic bone grafts are non-inferior to autologous bone grafts, despite their perceived disadvantages (e.g. being biologically inert). In conclusion, surgeons should consider synthetic bone grafts when optimising peri-operative patient morbidity, particularly in complex tibial plateau fractures, where this work is most applicable

Introduction: Chondral lesions are the second most common pathology encountered during hip arthroscopy. Microfracture is a simple and effective technique to treat chondral lesions with proven long term results in the knee. However, there is little evidence to confirm the ability of microfracture to produce repair tissue in hip joint. Methods: Patients with acetabular chondral defect treated with microfracture during primary arthroscopy and who had a subsequent hip arthroscopy enabling visualisation of the treated chondral defect were included in the study. Over a three year period 185 patients had microfracture for treatment of full thickness chondral defect. 11 patients (8 males and 3 females) with a mean age of 35 years (range 17–54 years) who had revision hip arthroscopy form the study population. The size of chondral defect was measured at the time of primary arthroscopy. Microfracture was performed using arthroscopic awls with a standard technique. Postoperatively a strict rehabilitation protocol was followed. The extent and quality of repair tissue was assessed by visual inspection at second look arthroscopy. Results: All patients had chondral lesions confined to the antero-superior aspect of the acetabulum with an associated labral tear. None had diffuse osteoarthritis. The average defect measured 180 mm2 (range 50–300). The mean time interval between primary and revision arthroscopy was 12 months. Excluding one failure the overall percent fill of the defects was 95% (range 75 – 100) with good quality cartilage. Discussion: Only one other series has reported on the macroscopic results of microfracture in the hip. Our series agrees with the results of those authors. These similar results from 2 centres confirm that arthroscopic microfracture is an effective treatment for acetabular chondral lesions in carefully selected patients

Abstract. Objectives. The aim of this work was to compare the different techniques and the different fluid permeability of the tissue following each technique through assessing the flow of radiopaque contrast agent using μCT image analysis and 3D modelling. Methods. Donated human tali specimens (n=12) were prepared through creating a 10mm diameter chondral defect in three different regions of each talus. Each region then underwent one of three surgical techniques: 1) Fine wire drilling, 2) Nanofracture or 3) Microfracture, equidistant sites in each defect to ensure even distribution. Each region then had an addition of 0.1 ml radiopaque contrast agent (Omnipaque™ 300), imaged using a clinical μCT scanner (SCANCO Medical AG, 73.6 μm resolution). Each μCT scan was segmented using Slicer 3D software (The Slicer Community, 2023 3D Slicer (5.2.2)). The segmentation package was used to segment the bone and contrast agent regions in each different surgical site of each sample. Each defect site was created into a cylinder and the ratio of segmented pixels of contrast agent against bone. Results. The μCT analysis indicated that across the 12 samples, eight nanofracture regions demonstrated flow of the contrast agent either to the depth of the fracture site or deeper. Some lateral flow was also observed in these sites. eight microfracture regions demonstrated that the flow of the contrast agent was localised to the fracture site and a preferential flow laterally. In only one sample, did a fine wire drilling region demonstrate any fluid flow. In this sample, contrast agent had permeated through the drilling site to the bottom and some sub-site permeation was observed. However, in all samples that showed no permeation of contrast agent through the fracture site, a layer of contrast agent on the chondral surface or minor permeation through to the sub-chondral surface. Segmentation of each sample site showed a significant increase (n=12, p<0.05) in fluid flow of the contrast agent in the nanofracture sites (11%) compared to microfracture (5%) and fine wire drilling (2%). Conclusions. Nanofracture showed significantly improved fluid permeability throughout the surrounding trabecular structure, when compared to microfracture and fine wire drilling. Microfracture appears to allow some fluid flow, but only confined to the immediate area around the fracture site, while fine wire drilling appears to allow a comparably small amount, if not no fluid flow through the surrounding trabecular tissue. This conclusion is reinforced by previous literature that concluded the damage to the structure of the trabecular tissue is reduced when using nanofracture, compared to the other two techniques. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Difficulties arise when counselling younger patients on the long-term sequelae of a minor knee chondral defect. This study assesses the natural history of patients with grade 2 Outerbridge chondral injuries of the medial femoral condyle at arthroscopy. We reviewed all arthroscopies performed by one surgeon over 12 years with Outerbridge grade 2 chondral defects. Patients aged 30 to 59 were included. Meniscal injuries found were treated with partial menisectomy. All patients had five-year follow up minimum. Primary outcome measure was further interventions of total or unicondylar arthroplasty or high tibial osteotomy. We analysed 3,344 arthroscopies. Average follow up was 10 years (Range 5–17 years). A total of 357 patients met inclusion criteria of which 86 had isolated medial femoral condyle disease. Average age was 50 at the time of arthroscopy. Average BMI at surgery was 31.7 and average chondral defect area was 450 mm. 2. Isolated MFC chondral disease had a 10.5% intervention rate. Intervention occurred at a mean of 8.5 years post primary arthroscopy. In young patients Outerbridge II chondral injuries affecting ≥2 compartments have a high rate of further intervention within a decade. This information is crucial in counselling young patients on long-term sequelae of benign chondral lesions

Arthroscopic hip procedures have increased dramatically over the last decade as equipment and techniques have improved. Patients who require hip arthroscopy for femoroacetabular impingement on occasion require surgery on the contralateral hip. Previous studies have found that younger age of presentation and lower Charlson comorbidity index have higher risk for requiring surgery on the contralateral hip but have not found correlation to anatomic variables. The purpose of this study is to evaluate the factors that predispose a patient to requiring subsequent hip arthroscopy on the contralateral hip. This is an IRB-approved, single surgeon retrospective cohort study from an academic, tertiary referral centre. A chart review was conducted on 310 primary hip arthroscopy procedures from 2009-2020. We identified 62 cases that went on to have a hip arthroscopy on the contralateral side. The bilateral hip arthroscopy cohort was compared to unilateral cohort for sex, age, BMI, pre-op alpha angle and centre edge angle measured on AP pelvis XRay, femoral torsion, traction time, skin to skin time, Tonnis grade, intra-op labral or chondral defect. A p-value <0.05 was deemed significant. Of the 62 patients that required contralateral hip arthroscopy, the average age was 32.7 compared with 37.8 in the unilateral cohort (p = 0.01) and BMI was lower in the bilateral cohort (26.2) compared to the unilateral cohort (27.6) (p=0.04). The average alpha angle was 76.3. 0. in the bilateral compared to 66. 0. in the unilateral cohort (p = 0.01). Skin to skin time was longer in cases in which a contralateral surgery was performed (106.3 mins vs 86.4 mins) (p=0.01). Interestingly, 50 male patients required contralateral hip arthroscopy compared to 12 female patients (p=0.01). No other variables were statistically significant. In conclusion, this study does re-enforce existing literature by stating that younger patients are more likely to require contralateral hip arthroscopy. This may be due to the fact that these patients require increased range of motion from the hip joint to perform activities such as sports where as older patients may not need the same amount of range of motion to perform their activities. Significantly higher alpha angles were noted in patients requiring contralateral hip arthroscopy, which has not been shown in previous literature. This helps to explain that larger CAM deformities will likely require contralateral hip arthroscopy because these patients likely impinge more during simple activities of daily living. Contralateral hip arthroscopy is also more common in male patients who typically have a larger CAM deformity. In summary, this study will help to risk stratify patients who will likely require contralateral hip arthroscopy and should be a discussion point during pre-operative counseling. That offering early subsequent or simultaneous hip arthroscopy in young male patients with large CAMs should be offered when symptoms are mild

Chondral defects on the patella are a difficult problem in the young active patient and there is no consensus on how to treat these injuries. Fresh osteochondral allografts are a valid option for the treatment of full-thickness osteochondral defects and can be used to restore joint function and reduce pain. The primary purpose of this study was to investigate the clinical and subjective outcomes of a series of patients following fresh osteochondral allograft transplantation for isolated chondral defects of the patella. A series of 5 patients underwent surgery using an open approach for graft transplantation. A strict protocol for the allograft tissue was followed. Transplant recipients must be aged <60, have a full-thickness, isolated chondral lesion and have failed previous traditional treatments. The fresh allografts are hypothermically stored at 4°C in X-VIVO10 media for up to 30 days to maintain cartilage viability. Pre- and post-operative clinical measures including knee stability, range of motion, and quadriceps girth were completed. Post-operative plain radiographs were completed including weight-bearing AP, lateral and skyline views. Patient-centred outcome measures including the Knee Osteoarthritis Outcome Score (KOOS) and the Knee Society Score (KSS) were gathered a minimum of 1-year post-operative. Descriptive and demographic data were collected for all patients. A paired t-test was employed to determine the difference between the pre-operative and post-operative outcomes. All patients were female, with a mean age of 27.4 (SD 3.65). Knee ligament stability was similar pre- and post-operatively. Knee ROM assessment of flexion and extension demonstrated a less than 10° increase from pre to post-operative. Quadriceps girth measurements demonstrated a mean change of 0.5 cm from pre- to post-operative for the surgical limb. Post-operative radiographs demonstrated incorporation of the graft in 4/5 cases within 6-months of surgery. One patient developed fragmentation of the graft after 18-months, and one patient had a subsequent trochleoplasty for persistent pain. The mean KOOS domain scores demonstrated significant improvement (p<0.05) as follows: Symptoms pre-op = 28.57, post-op = 55; Pain pre-op 28.89, post-op = 57.22; ADLs pre-op = 48.92, post-op = 66.18; Sports/Recreation pre-op = 6, post-op = 32; and QoL pre-op = 12.5, post-op = 42.5. Mean pre-op surgical versus non-surgical limb KSS scores were 107.4 and 179 respectively. The mean post-op surgical versus non-surgical limb KSS scores were 166 and 200. Isolated chondral defects of the patella can cause substantial pain, reduced function, and can be challenging to address surgically. This series of 5 cases demonstrated improved function, KOOS and KSS for 4/5 patients. To our knowledge this is a novel biological procedural technique for this problem, which has shown promising results making it a viable treatment option for young active patients with osteochondral defects of the patella