The aim of this study was to determine both the incidence of, and the reoperation rate for, postoperative periprosthetic femoral fracture (POPFF) after total hip arthroplasty (THA) with either a collared cementless (CC) femoral component or a cemented polished taper-slip (PTS) femoral component. We performed a retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All POPFFs were identified using regional radiograph archiving and electronic care systems.Aims
Methods
Chronic osteomyelitis is a complex and challenging condition the successful treatment of which requires a specialist multidisciplinary approach. Prior to tertiary referral to a specialist Orthoplastic Unit, patients often receive multiple courses of antibiotics, in usually unsuccessful attempts, to eradicate infection. This often results in the development of chronic polymicrobial infection. We reviewed the intra-operative cultures of patients treated in our Orthoplastic unit over a 9-year period from 2012–2021 to determine the spectrum of polymicrobial cultures and the relationship to pre-operative cultures. We reviewed the electronic care records and laboratory results of all patients referred to or directly admitted to our unit with a diagnosis of chronic osteomyelitis between 2012–2021. We checked all culture results, antibiotic sensitivities and prescription for treatment. We also checked for any recurrence of infection within 1 year. 60 patients were treated over the 9-year period. 9 upper and 51 lower limbs. The most common referral sources were from the surgical specialties of Trauma & Orthopaedics and Plastic Surgery (62%) while an equal amount came from the Emergency Department and other inpatient medical teams, each making up 15%. A small cohort (8%) developed the infection while still being followed up post fixation. Aetiology of Infection were post fracture fixation 41 (68%), spontaneous osteomyelitis 10 (17%), soft tissue infection 4 (7%). The remaining 5 patients (8%) had a combination failed arthroplasty, arthrodesis and chronic infection from ring sequestrum. 58 patients (97%) had positive cultures with 26 being polymicrobial. 12 cultures were gram negative (G-ve), 11 G+ve 12, 4 anaerobic and 1 Fungal. In 24 patients (40%) the pre-operative cultures and antibiotic sensitivities did not correspond to the intra-operative cultures and sensitivities. 55 patients (92%) required dual or triple therapy with 8% requiring further debridement and extended therapy. 2 (3%) patients had failed treatment requiring amputation.Materials & Methods
Results
Periprosthetic joint infection (PJI) occurs in 0.2-2% of primary hip and knee arthroplasty and is a leading cause of revision surgery, impaired function, and increased morbidity and mortality. Topical, intrawound vancomycin administration allows for high local drug concentrations at the surgical site and has demonstrated good results in prevention of surgical site infection after spinal surgery. It is a promising treatment to prevent infection following hip and knee arthroplasty. Prior studies have been limited by small sample sizes and the low incidence of PJI. This systematic review and meta-analysis was performed to determine the effectiveness of topical vancomycin for the primary prevention of PJI in hip and knee arthroplasty. A search of Embase, MEDLINE, and PubMed databases as of June 2020 was performed according to PRISMA guidelines. Studies comparing topical vancomycin to standard perioperative intravenous antibiotics in primary THA and TKA with a minimum of three months follow-up were identified. The results from applicable studies were meta-analysed to determine the impact of topical vancomycin on PJI rates as well as wound-related and overall complications. Results were expressed as odds ratios (ORs) and 95% confidence intervals Nine comparative observational studies were eligible for inclusion. 3371 patients treated with 0.5-2g of topical vancomycin were compared to 2884 patients treated with standard care. Only one of nine studies found a significantly lower rate of PJI after primary THA or TKA (OR 0.09-1.97, p=0.04 for one study, p>0.05 for eight of nine studies), though meta-analysis showed a significant benefit, with vancomycin lowering PJI rates from 1.6% in controls to 0.7% in the experimental group (OR 0.47, p=0.02, Figure 1). Individually, only one of five studies showed a significant benefit to topical vancomycin in THA, while none of seven studies investigating PJI after TKA showed a benefit to topical vancomycin. In meta-analysis of our subgroups, there was a significant reduction in PJI with vancomycin in THA (OR 0.34, p=0.04), but there was no significant difference in PJI after TKA (OR 0.60, p = 0.13). In six studies which reported complication rates other than PJI, there were no significant differences in overall complication rates with vancomycin administration for any study individually (OR 0.48-0.94, p>0.05 for all studies), but meta-analysis found a significant difference in complications, with a 6.7% overall complication rate in controls compared to 4.8% after topical vancomycin, largely driven by a lower PJI incidence (OR 0.76, p=0.04). Topical vancomycin is protective against PJI after hip and knee arthroplasty. No increase in wound-related or overall complication rates was found with topical vancomycin. This meta-analysis is the largest to date and includes multiple recent comparative studies while excluding other confounding interventions (such as povidone-iodine irrigation). However, included studies were predominantly retrospective and no randomized-controlled trials have been published. The limited evidence summarized here indicates topical vancomycin may be a promising modality to decrease PJI, but there is insufficient evidence to conclusively show a decrease in PJI or to demonstrate safety. A prospective, randomized-controlled trial is ongoing to better answer this question. For any figures or tables, please contact the authors directly.
Distal radius fractures (DRFs) are common injuries that represent 17% of all adult upper extremity fractures. Some fractures deemed appropriate for nonsurgical management following closed reduction and casting exhibit delayed secondary displacement (greater than two weeks from injury) and require late surgical intervention. This can lead to delayed rehabilitation and functional outcomes. This study aimed to determine which demographic and radiographic features can be used to predict delayed fracture displacement. This is a multicentre retrospective case-control study using radiographs extracted from our Analytics Data Integration, Measurement and Reporting (DIMR) database, using diagnostic and therapeutic codes. Skeletally mature patients aged 18 years of age or older with an isolated DRF treated with surgical intervention between two and four weeks from initial injury, with two or more follow-up visits prior to surgical intervention, were included. Exclusion criteria were patients with multiple injuries, surgical treatment with fewer than two clinical assessments prior to surgical treatment, or surgical treatment within two weeks of injury. The proportion of patients with delayed fracture displacement requiring surgical treatment will be reported as a percentage of all identified DRFs within the study period. A multivariable conditional logistic regression analysis was used to assess case-control comparisons, in order to determine the parameters that are mostly likely to predict delayed fracture displacement leading to surgical management. Intra- and inter-rater reliability for each radiographic parameter will also be calculated. A total of 84 age- and sex-matched pairs were identified (n=168) over a 5-year period, with 87% being female and a mean age of 48.9 (SD=14.5) years. Variables assessed in the model included pre-reduction and post-reduction radial height, radial inclination, radial tilt, volar cortical displacement, injury classification, intra-articular step or gap, ulnar variance, radiocarpal alignment, and cast index, as well as the difference between pre- and post-reduction parameters. Decreased pre-reduction radial inclination (Odds Ratio [OR] = 0.54; Confidence Interval [CI] = 0.43 – 0.64) and increased pre-reduction volar cortical displacement (OR = 1.31; CI = 1.10 – 1.60) were significant predictors of delayed fracture displacement beyond a minimum of 2-week follow-up. Similarly, an increased difference between pre-reduction and immediate post reduction radial height (OR = 1.67; CI = 1.31 – 2.18) and ulnar variance (OR = 1.48; CI = 1.24 – 1.81) were also significant predictors of delayed fracture displacement. Cast immobilization is not without risks and delayed surgical treatment can result in a prolong recovery. Therefore, if reliable and reproducible radiographic parameters can be identified that predict delayed fracture displacement, this information will aid in earlier identification of patients with DRFs at risk of late displacement. This could lead to earlier, appropriate surgical management, rehabilitation, and return to work and function.
Nearly one quarter of ankle fractures have a recognized syndesmosis injury. An intact syndesmosis ligament complex stabilizes the distal tibio-fibular joint while allowing small, physiologic amounts of relative motion. When injured, malreduction of the syndesmosis has been found to be the most important independent factor that contributes to inferior functional outcomes. Despite this, significant variability in surgical treatment remains. This may be due to a poor understanding of normal dynamic syndesmosis motion and the resultant impact of static and dynamic fixation on post-injury syndesmosis kinematics. As the syndesmosis is a dynamic structure, conventional CT static images do not provide a complete picture of syndesmosis position, giving potentially misleading results. Dynamic CT technology has the ability to image joints in real time, as they are moved through a range-of-motion (ROM). The aim of this study was to determine if syndesmosis position changes significantly throughout ankle range of motion, thus warranting further investigation with dynamic CT. This is an a priori planned subgroup analysis of a larger multicentre randomized clinical trial, in which patients with AO-OTA 44-C injuries were randomized to either Tightrope or screw fixation. Bilateral ankle CT scans were performed at 1 year post-injury, while patients moved from maximal dorsiflexion (DF) to maximal plantar flexion (PF). In the uninjured ankles, three measurements were taken at one cm proximal to the ankle joint line in maximal DF and maximal PF: Anterior (ASD), middle (MSD), and posterior (PSD) syndesmosis distance, in order to determine normal syndesmosis position. Paired samples t-tests compared measurements taken at maximal DF and maximal PF. Twelve patients (eight male, six female) were included, with a mean age of 44 years (±13years). The mean maximal DF achieved was 1-degree (± 7-degrees), whereas the mean maximal PF was 47-degrees (± 8-degrees). The ASD in DF was 3.0mm (± 1.1mm) versus 1.9mm (± 0.8mm) in PF (p<0.01). The MSD in DF was 3.3mm (±1.1mm) versus 2.3mm (±0.9mm) in PF (p<0.01). The PSD in DF was 5.3mm (±1.5mm) versus 4.6mm (±1.9mm) in PF (p<0.01). These values are consistent with the range of normal parameters previously reported in the literature, however this is the first study to report the ankle position at which these measurements are acquired and that there is a significant change in syndesmosis measurements based on ankle position. Normal syndesmosis position changes in uninjured ankles significantly throughout range of motion. This motion may contribute to the variation in normal anatomy previously reported and controversies surrounding quantifying anatomic reduction after injury, as the ankle position is not routinely standardized, but rather static measurements are taken at patient-selected ankle positions. Dynamic CT is a promising modality to quantify normal ankle kinematics, in order to better understand normal syndesmosis motion. This information will help optimize assessment of reduction methods and potentially improve patient outcomes. Future directions include side-to-side comparison using dynamic CT analysis in healthy volunteers.
Advances in orthopaedic surgery have led to minimally invasive techniques to decrease patient morbidity by minimizing surgical exposure, but also limits direct visualization. This has led to the increased use of intraoperative fluoroscopy for fracture management. Unfortunately, these procedures require the operating surgeon to stay in close proximity to the patient, thus being exposed to radiation scatter. The current National Council on Radiation Protection recommends no more than 50 mSv of radiation exposure to avoid ill-effects. Risks associated with radiation exposure include cataracts, skin, breast and thyroid cancer, and leukemia. Despite radiation protection measures, there is overwhelming evidence of radiation-related diseases in orthopaedic surgeons. The risk of developing cancer (e.g. thyroid carcinoma and breast cancer) is approximately eight times higher than in unexposed workers. Despite this knowledge, there is a paucity of evidence on radiation exposure in orthopaedic surgery residents, therefore the goal of this study is to quantify radiation exposure in orthopaedic surgery residents. We hypothesize that orthopaedic surgery residents are exposed to a significant amount of radiation throughout their training. We specifically aim to: 1) quantify the amount of radiation exposure throughout a Canadian orthopaedic residency training program and 2) determine the variability in resident radiation exposure by rotation assignment and year of training. This ongoing prospective cohort study includes all local orthopaedic surgery residents who meet eligibility criteria. Inclusion criteria: 1) adult residents in an orthopaedic surgery residency program. Exclusion criteria: 1) female residents who are pregnant, and 2) residents in a non-surgical year (i.e. leave of absence, research, Masters/PhD). After completion of informed consent, each eligible resident will wear a dosimeter to measure radiation exposure in a standardized fashion. Dosimeters will be worn on standardized lanyards underneath lead protection in their left chest pocket during all surgeries that require radiation protection. Control dosimeters will be worn on the outside of each resident's scrub cap for comparison. Dosimeter readings will then be reported on a monthly and rotational basis. All data will be collected on a pre-developed case report form. All data will be de-identified and stored on a secure electronic database (REDCap). In addition to monthly and rotational dosimeter readings, residents will also report sex, height, level of training, parental status, and age for secondary subgroup analyses. Residents will also report if they have personalized lead or other protective equipment, including lead glasses. Resident compliance with dosimeter use will be measured by self report of >80% use on operative days. Interim analysis will be performed at the 6-month time point and data collection will conclude at the 1 year time point. Data collection began in July 2018 and interim 6-month results will be available for presentation at the CORA annual meeting in June 2019. This is the first prospective study quantifying radiation exposure in Canadian orthopaedic residents and the results will provide valuable information for all Canadian orthopaedic training programs.
Surgical fixation of tibial plateau fractures in elderly patients with open reduction and internal fixation (ORIF) provides inferior outcomes compared to younger patients. Primary total knee arthroplasty (TKA) may be of benefit in patients with pre-existing arthritis, marked osteopenia, or severe fracture comminution. Rationale for primary TKA includes allowing early mobility in hopes of reducing associated complications such as deconditioning, postoperative pneumonia, or venous thromboembolism, and reducing post-traumatic arthritis which occurs in 25% to 45% of patients and requires revision TKA in up to 15%. Subsequent revision TKA has been shown to have significantly worse outcomes than TKA for primary osteoarthritis. This systematic review sought to elicit the clinical outcomes and peri-operative complication rates following primary TKA for tibial plateau fractures. A comprehensive search of MEDLINE, Embase, and PubMed databases from inception through March 2018 was performed in accordance with PRISMA guidelines. Two reviewers independently screened papers for inclusion and identified studies featuring perioperative complications and clinical outcomes following primary TKA for tibial plateau fractures. Studies were included for final data analysis if they met the following criteria: (1) studies investigating TKA as the initial treatment for tibial plateau fractures, (2) patients must be ≥ 18 years old, (3) have a minimum ≥ 24-month follow-up, and (4) must be published in the English language. Case series, cohort, case-control, and randomized-control trials were included. Weighted means and standard deviations are presented for each outcome. Seven articles (105 patients) were eligible for inclusion. The mean age was 73 years and average follow-up was 39 months. All-cause mortality was 4.75% ± 4.85. The total complication rate was 15.2% ± 17.3% and a total of eight patients required revision surgery. Regarding functional outcomes, the Knee Society score was most commonly reported. The average score on the knee subsection was 85.6 ± 5.5 while the average function subscore was 64.6 ± 13.7. Average range of motion at final follow-up was 107.5° ± 10°. Total knee arthroplasty for the treatment of acute tibial plateau fractures is enticing to allow early mobility and weightbearing. However, complication rates remain high. Functional outcomes are similar to patients treated with ORIF or delayed arthroplasty. Given these findings, surgeons should be highly selective in performing TKA for the immediate treatment of tibial plateau fractures.
The syndesmosis ligament complex stabilizes the distal tibiofibular joint, while allowing for the subtle fibular motion that is essential for ankle congruity. Flexible fixation with anatomic syndesmosis reduction results in substantial improvements in functional outcomes. New dynamic CT technology allows real-time imaging, as the ankle moves through a range of motion. The aim of this study was to determine if dynamic CT analysis is a feasible method for evaluating syndesmosis reduction and motion following static and flexible syndesmosis fixation. This is a subgroup analysis of a larger multicenter randomized clinical trial, in which patients with AO 44-C injuries were randomized to either Tightrope (one knotless Tightrope, Group T) or screw fixation (two 3.5-mm cortical screws, Group S). Surgical techniques and rehabilitation were standardized. Bilateral ankle CT scans were performed at one year post-injury, while patients moved from maximal dorsiflexion (DF) to maximal plantar flexion (PF). Three measurements were taken at one cm proximal to the ankle joint line in maximal DF and maximal PF: anterior, midpoint, and posterior tibiofibular distances. T-tests compared Group T and Group S, and injured and uninjured ankles in each group. Fifteen patients (six Group T [three male], nine Group S [eight male]) were included. There was no difference for mean age (T = 42.8 ± 14.1 years, S = 37 ± 12.6, P = 0.4) or time between injury and CT scan (T = 13 ± 1.8 months, S = 13.2 ± 1.8, P = 0.8). Of note in Group S, seven of nine patients had at least one broken screw and one additional patient had screws removed by the time of their dynamic CT. There was no significant difference between treatment groups for tibiofibular distance measurements in maximal PF or DF. Group T showed no significant difference between the injured and uninjured side for tibiofibular measurements in maximal PF and DF, suggesting anatomic reduction. For Group S, however, there was a significantly larger distance for all three measurements at maximal PF compared to the uninjured ankle (all P < 0 .05). In all but one Group S patient, screws were broken or removed prior to their dynamic CT, allowing possible increased syndesmotic motion, similar to Group T. Despite this, dynamic CT analysis detected increased tibiofibular distance in Group S as ankles moved into maximal PF when compared with the uninjured ankle. Given the importance of anatomic syndesmosis reduction, dynamic ankle CT technology may provide valuable physiologic information warranting further investigation.
Total joint arthroplasty (TJA) is projected to be the most common elective surgical procedure in the coming decades, however TJA now accounts for the largest expenditure per procedure for Medicare and Medicaid provided interventions. This is coupled with increasing complexity of surgical care and concerns about patient satisfaction. The Perioperative Surgical Home (PSH) model has been proposed as a method to both improve patient care and reduce costs. The PSH model provides evidence-based protocols and pathways from the time of surgical decision to after postoperative discharge. PSH pathways can further be standardized with integration into electronic medical records (EMRs). The purpose of this study is to see if the implementation of PSH with and without EMR integration effects patient outcomes and cost. A retrospective review was performed for all patients who underwent elective primary total joint arthroplasty at our institution from January 1, 2012 to April 1, 2018. Three cohorts were compared. The first cohort included patients before the implementation of the PSH model (January 1, 2012 - December 31, 2014). The second cohort included patients in the PSH model without EMR integration (January 1, 2015 – August 1, 2016). The third cohort included patients in the PSH model with EMR integration (August 1, 2016 - April 1, 2018). The clinical outcome criteria measured were average hospital length of stay (LOS), 30-day readmission rates, and discharge disposition. Financial data was collected for each cohort and primary measurements included average total cost, diagnostic cost, anesthesia cost, laboratory cost, room and board cost, and physical therapy cost.Introduction
Methods
YouTube is a video sharing platform that is a common resource for patients seeking medical information. The objective of this study is to assess the educational quality of YouTube videos pertaining to total knee arthroplasty and knee arthritis. A systematic search for the terms “knee replacement” and “knee arthritis” was performed using Youtube's search function. Data from the 60 most relevant videos were collected for each search term. Videos not in English or those without audio or captions were excluded. Quality assessment checklists with a scale of 0 to 10 points were developed to evaluate the video content. Videos were grouped into poor quality (grade 0–3), acceptable quality (grade 4–7) and excellent quality (grade 8– 10), respectively. Four independent reviewers assessed the videos using the same grading system and independently scored all videos. Discrepancies regarding the scoring were clarified by consensus discussion.PURPOSE
METHODS
To characterize the quality of flap tissues and the resident cells in order to provide a scientific rationale for reattaching flap tissues during surgery. 11 acetabular chondral flaps and 3 non-delaminated cartilage samples were resected during open hip surgeries and the anatomical orientation was marked. The viability was measured in 7 flaps with Live Dead staining and the distribution of the extracellular matrix components was investigated in 7 oriented flaps by histology. The chondrogenic potential of the residing cells (P2) was investigated via pellets assays (5 flaps). Their capacity to outgrow from flap particles was tested upon encapsulation in 4mm-diameter fibrin glue discs (6 flaps). The viability in flaps was 49.4 ± 6.5 % compared to 70.6 ± 8.2 % in non-delaminated cartilage, (not significant). Histology showed a progression of fibrillation from the delaminated side towards the site of attachment. This degraded state correlated with the capacity of the cells to outgrow, with 60.6 ± 33 % of the gel area covered by migrating cells after 4 weeks in culture. However, the cells in flaps showed a decreased chondrogenic potential than chondrocytes from non-delaminated cartilage. Our findings indicate that flaps contain viable cells that can outgrow from the tissue due to the degraded state of the matrix. The poor chondrogenic property of the cells suggests they are unlikely to produce enough matrix to provide a solid attachment of the delaminated tissue upon migration.
This study analyzes position of the peroneal tendons and status of the superior peroneal retinaculum (SPR) whenever a lateral malleolar bony flake fracture occurs. Twenty-four patients had a lateral malleolar bony fleck on anteroposterior ankle radiographs, either in isolation or associated with other hindfoot injuries. We studied size of the bony flecks, presence or absence of peroneal tendon dislocation and pathoanatomy on CT scans.Background
Methods
Femur neck fractures (NOF) in the young could result in mal-union, non-union and avascular necrosis of the femoral head. Osteosynthesis is the standard of management in NOFs in young patient above complications sometimes end in Arthroplasty. The aim of our study is to identify predictors of NOF failures in the young population. A retrospective study conducted in a single center. Patients with NOF fractures below the age of <50y excluding pathological and osteoporotic fractures were assessed in the period from 2005–2008. The mean follow-up was 22 months (6–40). Fractures were classified according to Gardens classification. Our Aim was to identify causative factors for fixation failures. Analysis was done using SPSS 17.0.Introduction
Method
The purpose of this study was to understand the effects of terminal sterilisation and residual calcium on human demineralised bone matrix (DBM) in ectopic bone formation in nude rat. The intramuscular implantation of human DBM prepared by the Queensland Bone Bank (QBB) from four donors into eight male athymic rats was used to assess osteoinductivity. The DBM contained different levels of residual calcium and treated with or without gamma-irradiation at 11kGy. At 6 weeks post-implantation, calcium deposition was assessed by manual palpitation and radiological imaging. Tissue morphology and cellular interactions was analysed using various histological staining methods whilst protein expression of anabolic and catabolic biomarkers were examined through immunohistochemistry. All results were then analysed in qualitative, semi-quantitative and quantitative manners and tested for statistical significance. Bone formation was observed in all specimens at the gross level. This was confirmed by histology which revealed bony capsules surrounded by soft tissue in the muscle pockets and differences in tissue components. On a cellular level, variations in osteoclast expression were found between the two groups as well as amongst individual donors through statistical analysis which resulted in an imbalance of the expression of anabolic and catabolic markers. Furthermore, a positive relationship between residual calcium and new bone formation in gamma irradiated DBM samples was found. To date, no studies have compared the effect of calcium in gamma irradiated DBM. Our results suggest that gamma irradiation even at low doses and residual calcium may affect new bone formation. Taken together, this study stresses the importance of selecting ideal conditions for graft processing and the need to identify an optimal level of irradiation and remaining calcium levels that confers a balance between osteoinductivity and sterility.
Ulnar styloid fractures may contribute to negative outcomes after distal radius fractures due to its association with distal radioulnar (DRUJ)instability and injuries of the triangular fibrocartilaginous (TFCC) complex. This study assesses clinical outcomes of untreated ulnar styloid fractures after internal fixation of distal radius fractures. Patients undergoing operative fixation for distal radius fractures from January 2004 to June 2006 were divided into those with and without ulnar styloid fractures. The two groups were compared in terms of wrist range of motion, ulnar sided wrist pain, extensor carpi ulnaris (ECU) tendinitis, TFCC grind test, and DASH scores. Thirty-one males and 23 females aged 50.9 years(18–88 yrs, SD 16.5) were assessed. At 24 months, the presence of ulnar styloid fractures had no impact on ulnar-sided wrist pain (p=0.331), TFCC grind test(p=0.917) and distal radioulnar joint instability (p=0.957). There was a tendency towards ECU tendinitis (23.8% vs 6.1%, p= 0.058) in patients with ulnar styloid fractures. There was no significant difference in the range of motion and overall DASH scores (8.0 vs 5.9, p=0.474). No association was found between ulnar styloid fractures and DRUJ instability in this study. Ulnar styloid fractures behave like avulsion injuries. In the absence of DRUJ instability, conservative management of ulnar styloid fractures during operative treatment of distal radius fractures do not compromise clinical outcome.
Bone tendon junction (BTJ) healing after injury is often slow, without restoration of fibrocartilage transition zone. Fibrocartilage formation has been observed near articular cartilage. It was hypothesised that articular cartilage interposition could stimulate fibrocartilage transition zone regeneration and improve BTJ healing. Partial patellectomy repair was performed in goat. Articular cartilage harvested from excised patella segment was interposed between the patella and patellar tendon during repair. No cartilage interposition was used in control group. Samples were harvested at six, 12, and 24 weeks for histological examination (n=6 each). The histological images were digitised and analyzed using an image analysis system. Healing progress was assessed by the amount of new bone formation and fibrocartilage transition zone regeneration. Quantitative data were analyzed using SPSS version 14.0. Statistic al significance level was set at p <
0.05. There was progressive increase in maximum new bone length and area of new bone formed with time (p<
0.05, Kruskal-Wallis test). No difference was observed between treatment groups. Articular cartilage interposition resulted in more fibrocartilage regeneration and higher proteoglycan uptake at all time points. At 24 weeks, length of fibrocartilage formed measured 7760 ± 629 μm with articular cartilage interposition, compared with 787± 274 μm in control (p = 0.002, Mann-Whitney test). Safranin O length measured 3301 ± 1236 μm with articular cartilage interposition, compared with 277 ± 187 μm in control (p = 0.03, Mann-Whitney test). Autologous articular cartilage interposition stimulates fibrocartilage transition zone regeneration in BTJ repair without affecting bone formation.
