Introduction. The heterogeneity of outcomes used in the field of lower limb lengthening surgery (LLLS) affects our ability to synthesize evidence. This hampers robust systematic reviews and treatment recommendations for clinical practice. Ultimately this reduces the impact of research for both patients and healthcare professionals. This scoping review aimed to describe the outcomes and outcome measurement instruments (OMIs) used within the field of LLLS. Method. A systematic literature search of WOS, Scopus, Embase, MEDLINE, and the Cochrane Library identified all studies reporting outcomes in children and adults after LLLS. All outcomes and OMIs were extracted verbatim. An iterative process was used to group outcome terms under standardized outcome headings categorized using the COMET Taxonomy of Outcomes. Result. Data saturation was achieved in 2020. A total of 142 studies were included between 2024-2020, reporting 2964 verbatim outcomes with 663 standardized outcome terms collapsed into 119 outcome headings (subdomains). A total of 29 patient-reported and 26 clinician-reported outcome instruments were identified. The most commonly reported outcome was “Lengthening amount”, reported in over 72% of the included studies, while “health-related quality of life” was measured in 16% and all life impact outcomes were reported in 19% of the included studies. Conclusion. A large number of peer-reviewed publications are available, demonstrating that significant resources are being devoted to research on LLLS. However, reported outcomes for people with LLLS are heterogeneous, subject to reporting bias, and vary widely in the definitions and measurement tools used to collect them. Outcomes likely to be important to patients, such as quality of life and measures of physical function, have been neglected. This scoping review identifies a need to standardize outcomes and outcome measures reported on patients recovering from lower limb lengthening surgery; this can be addressed by creating a core set of outcomes

The primary aim of this study was to compare the clinical outcomes of osteoid osteoma (OO) between the group of patients with the presence of nidus on biopsy samples from radiofrequency ablation (RFA) with those without nidus. Secondly, we aimed to examine other factors that may affect the outcomes of OO reflecting our experience as a tertiary orthopaedic oncology centre. We retrospectively reviewed 88 consecutive patients diagnosed with OO treated with RFA between November 2005 and March 2015, consisting of 63 males (72%) and 25 females (28%). Sixty-six patients (75%) had nidus present in their biopsy samples. Patients’ mean age was 17.6 years (4-53). Median duration of follow-up was 12.5 months (6-20.8). Lesions were located in the appendicular skeleton in seventy-nine patients (90%) while nine patients (10%) had an OO in the axial skeleton. Outcomes assessed were based on patients’ pain alleviation (partial, complete, or no pain improvement) and the need for further interventions. Pain improvement in the patient group with nidus in histology sample was significantly better than the group without nidus (OR 7.4, CI 1.35-41.4, p=0.021). The patient group with nidus on biopsy demonstrated less likelihood of having a repeat procedure compared to the group without nidus (OR 0.092, CI 0.016-0.542, p=0.008). Our study showed significantly better outcomes in pain improvement in appendicular lesions compared to the axially located lesions (p = 0.005). Patients with spinal lesions tend to have relatively poor pain relief than those with appendicular or pelvic lesions (p=0.007). Patients with nidus on histology had better pain alleviation compared to patients without nidus. The histological presence of nidus significantly reduces the chance of repeat interventions. The pain alleviation of OO following RFA is better in patients with appendicular lesions than spinal or axially located lesions

Introduction and Objective. Kinematic Alignment (KA) is a surgical technique that restores the native knee alignment following Total Knee Arthroplasty (TKA). The association of this technique with a medial pivot implant design (MP) attempts to reestablish the physiological kinematics of the knee. Aim of this study is to analyze the clinical and radiological outcomes of patients undergoing MP-TKA with kinematic alignment, and to assess the effect of the limb alignment and the orientation of the tibial component on the clinical outcomes. Materials and Methods. We retrospectively analyzed 63 patients who underwent kinematic aligned medial pivot TKA from September 2018 to January 2020. Patient-Related Outcomes (PROMs) and radiological measures were collected at baseline, 3 months and 12 months after surgery. Results. We demonstrated a significant improvement in the clinical and functional outcomes starting from 3 months after surgery. This finding was also confirmed at the longest follow-up. The clinical improvement was independent from the limb alignment and from the orientation of the tibial component. The radiological analysis showed that the patient's native limb alignment was restored, and that the joint line orientation maintained the parallelism to the floor when standing. This latter result has a particular relevance, as it may positively influence the outcomes, reducing the risk of wear and mobilization of the implant. Conclusions. The association of kinematic alignment and a medial pivot TKA implant allows for a fast recovery, good clinical and functional outcomes, independently from the final limb alignment and the tibial component orientation

Abstract. Objectives. Outcomes following different types of surgical intervention for FAI are well reported individually but comparative data is deficient. The purpose of this study was to conduct a systematic review (SR) and meta-analysis to analyse the outcomes following surgical management of FAI by hip arthroscopy (HA), anterior mini open approach (AMO) and surgical hip dislocation (SHD). Methods. This SR was registered with PROSPERO. An electronic database search of Pubmed, Medline and EMBASE for English and German language articles over the last 20 years was carried out according to the PRISMA guidelines. We specifically analysed and compared changes in patient reported outcome measures PROMs, α-angle, rate of complications, rate of revision and conversion to total hip arthroplasty (THA). Results. A total of 48 articles included for final analysis with a total of 4384 hips in 4094 patients. All subgroups showed a significant correction in mean alpha angle post-operatively with a mean change of 28.8° (95% CI, 21°-36.5°; p <0.01) after AMO, 21.1° (95% CI, 15.1°-27°; p <0.01) after SHD and 20.39° (95% CI, 15.66°-25.12°; p <0.01) after HA. AMO group showed a significantly higher increase in PROMs (3.7; 95% CI, 3.2–4.2; p <0.01) versus arthroscopy (2.47; 95% CI, 2.22–2.73; p <0.01) and SHD (2.4; 95% CI, 1.5–3.3; p <0.01). However, the rate of complications following AMO was significantly higher than HA and SHD. Conclusion. All three surgical approaches offered significant improvements in outcomes and radiological correction of cam deformities. All three groups showed similar rates of revision procedures and SHD had the highest rate of conversion to a THA. Revision rates was similar for all three revision procedures

Meniscal tears are the most common injury in the knee, affecting 66/100,000 people/year. Surgical treatment includes arthroscopic meniscectomy or meniscal repair. Little is known regarding medium-term outcomes following these procedures in isolated meniscal tears. This study aims to quantitatively evaluate patients with meniscal tears, and those who have undergone meniscectomy and meniscal repair using validated patient reported outcome measures (PROMs), further exploring factors which affect surgical outcomes.

This observational study screened 334 patients who underwent arthroscopic surgery at South Tyneside Hospital since August 2013. 134 patients with isolated meniscal tears were invited to complete postal PROMs. A combination of patient notes and radiological imaging was used to collect information of interest including age, gender, knee-laterality, injured meniscus, tear pattern, procedure performed, complications, and associated injuries.

A total of 115 patients (pre-operative patients with current meniscal tear (n=36), meniscectomy (n=63), meniscal repair (n=16)) were included in the analysis with 96% successful PROM completion. Both meniscectomy and meniscal repairs (mean 55-months follow-up) showed better outcomes than pre-operative patients with meniscal tears. Meniscal repairs demonstrated superior outcomes across all PROMs when compared to meniscectomy, with a greater mean overall KOOS score of 17.2 (p=0.009). Factors including higher pre-operative Kellgren-Lawrence Grade, pre-operative articular cartilage lesions and bilateral meniscectomies were shown to negatively influence outcomes.

Both meniscectomy and meniscal repair maintain clinical benefit at mean 55-months follow-up, affirming their use for treatment of meniscal tears. When feasible, meniscal repair should be performed preferentially over meniscectomy in isolated meniscal tears. Identified predictive factors allow adequate treatment stratification in specific patient groups.

This study aimed to quantify self-reported outcomes and walking gait biomechanics in patients following primary and revision THA. The specific goals of this study were to investigate: (i) if primary and revision THA patients have comparable preoperative outcomes; and (2) if revision THA patients have worse postoperative outcomes than primary THA patients.

Forty-three patients undergoing primary THA for osteoarthritis and 23 patients undergoing revision THA were recruited and followed longitudinally for their first 12 postoperative months. Reasons for revision were loosening (73%), dislocation (9%), and infection (18%). Patients completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS), and underwent gait analysis preoperatively, and at 3 and 12 months postoperatively. A 10 camera motion analysis system (V5 Vantage, Vicon, UK) recorded marker trajectories (100 Hz) during walking at self- selected speeds. A generic lower-body musculoskeletal model (Gait2392) was scaled using principal component analysis [1] and the inverse kinematics tool in Opensim 3.3 was used to compute joint angles for the lower limbs in the sagittal plane. Independent samples t-test were used to compare patient reported outcomes between the primary and revision groups at each timepoint. Statistical parametric mapping was used to compare gait patterns between the two groups at each timepoint.

Preoperatively, patients undergoing primary THA reported significantly worse pain (p<0.001), symptoms (p<0.001), function (p<0.001), and quality of life (p=0.004). No differences were observed at 3 and 12 months postoperatively between patients who had received a primary or revision THA. The only observed difference in gait pattern was that patients with a revision THA had reduced hip extension at 3 months, but no differences were observed preoperatively and 12 months.

Despite the suggestions in the literature that revision THA is bound to have worse outcomes compared to primary THA, we found no differences in in patient-reported outcomes and gait patterns at 12 months postoperatively. This suggests that it may be possible, in some circumstances, for patients following revision THA to achieve similar outcomes to their peers undergoing primary THA.

Cannulated hip screws are frequently used in the management of hip fractures. There have been concerns over the failure rate of the technique and the outcomes of those that subsequently require conversion to total hip replacement (THR).

This study utilised a database of over 600 cannulated hip screw (CHS) fixations performed over a 14-year period and followed up for a minimum of one year (1-14). We identified 57 cases where a conversion to THR took place (40 females, 17 males, mean age: 71.2 years). Patient demographics, original mechanism of injury, fracture classification, reason for fixation failure, time until arthroplasty, implant type and post-arthroplasty complications were recorded. Clinical outcomes were measured using the Oxford Hip Score.

The failure rate of cannulated screw treatment was 9.4% and the mean time from initial fixation to arthroplasty was 15.4 (16.5) months. Thirty six fractures were initially undisplaced and 21 were displaced. As one might expect the displaced cases tended to be younger but this didn't reach statistical significance [66.5(14.3) vs 72.7(13.1), p=0.1]. The commonest causes of failure were non-union (25 cases, 44%) and avascular necrosis (17 cases, 30%). Complications after THR consisted of one leg length discrepancy and one peri-prosthetic fracture. The mean Oxford score pre-arthroplasty was 12.2 (8.4), improving to 38.4 (11.1) at one-year. Although the pre op Oxford scores tended to be lower in patients with undisplaced fractures and higher ASA scores, the improvement was the same whatever the pre-op situation. The one-year Oxford score and the improvement in score are comparable to those seen in the literature for THR in general.

In conclusion, CHS has a high success rate and where salvage arthroplasty is required it can provide good clinical outcomes with low complication rates.

Solid organ transplant (SOT) recipients present an increased medical risk; however, few studies analyze the outcomes of these patients undergoing hip fracture surgery. This study aimes to determine the incidence of hip fracture in SOT patients and to compare the outcomes of SOT patients with matched non-SOT controls after hip fracture fixation.

A retrospective review identified 20 SOT patients with hip fracture at a single center from 2016 to 2021 and were matched (1:1) with a cohort of 20 patients with hip fracture without SOT. Patient outcomes, mortality/survival and clinical outcomes were compared between two groups.

The incidence of hip fracture in SOT patients was 20/1787, 1.1%. There were significant differences in mortality rate (73.3% SOT group vs. 26.7% non-SOT group; p<0.05). There were no differences in survival time (p=0.746). There were no differences in time to surgery (5.0 days SOT group vs. 3.1 days non-SOT group; p=0.109), however, there were significant differences in the hospital length of stay (14 days SOT group vs. 8.6 days non-SOT group; p=0.018). There were no differences regarding the complication rate between the two groups (9/20, 45% vs. 6/20, 30% in the SOT and non-SOT groups, respectively).

SOT patients with associated hip fracture required longer hospital length of stay than non-SOT patients. SOT patients did not show greater clinical complications; however, they presented higher mortality rate compared to non-SOT patients.

We sought to determine the relationship between patient preoperative psychological factors and postoperative THA outcomes.

We performed an electronic search up to December 2021 using the following terms: “(mental OR psychological OR psychiatric) AND (function OR trait OR state OR predictor OR health) AND (outcome OR success OR recovery OR response) AND total joint arthroplasty)”. Peer-reviewed, English language studies regarding THA outcomes were analyzed for preoperative patient mental health metrics and objective postoperative results regarding pain, functionality and surgical complications. We extracted study data, assessed the risk of bias of included studies, grouped them by outcome measure and performed a GRADE assessment.

Seventeen of 702 studies fulfilled inclusion criteria and were included in the review. Overall, compared to cohorts with a normal psychological status, patients with higher objective measures of preoperative depression and anxiety reported increased postoperative pain, decreased functionality and greater complications following THA. Additionally, participants with lower self-efficacy or somatization were found to have worse functional outcomes. Following surgery, both early and late pain scores remained higher in patients with preoperative depression and anxiety.

Preoperative depression and anxiety may negatively impact patient reported postoperative pain, physical function and complications following THA. A meta-analysis was not performed because of the heterogeneity of studies, specifically the use of differing pain scales and measures of physical and psychological function as well as varied follow-up times. Future research could test interventions to treat pre-operative depression or anxiety and explore longitudinal outcomes in THA patients. Surgeons should consider the preoperative psychological status when counseling patients regarding expected surgical outcomes and attempt to treat a patient's depression or anxiety prior to undergoing total hip arthroplasty.

The femur is a common site for skeletal bony metastases. The aim of this study is to evaluate the outcomes of femoral intramedullary nailing in prophylactic versus therapeutic treatment in femoral metastases. All femoral nails between April 2011 and November 2015 at a district general hospital were assessed. Intramedullary nailing performed for prophylactic or therapeutic management were included. Outcomes include mortality, survival time and length of stay in hospital. A total of 40 cases were included. In the prophylactic group there were 25 patients and in the therapeutic group there were 15 patients. In the prophylactic group, mean age was 70 years (range 41–91); male to female ratio is 23:17 and 26 patients of this group was deceased. In the therapeutic group, mean age was 76 years (range 56–92); male to female ratio 15:10 and 10 patients were deceased in this group. The most common primary was prostate carcinoma followed by breast carcinoma. In the prophylactic group, mean survival was 25 weeks (range 2–147) and in the therapeutic group mean survival was 20 weeks (range 2–39). The length of stay was 21 days (range 3–80) in the prophylactic group and 28 days (range 7–63) in the therapeutic group. Femoral nailing for metastases helps improve quality of life and we observed a mean survival time of 20–25 weeks postoperatively in both therapeutic and prophylactic nailing

Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are well-established operative interventions in the treatment of knee osteoarthritis (KOA). However, which of these interventions is more beneficial, to patients with KOA, is not known and remains a topic of much debate.

Aims: (i) To determine whether UKA or HTO is more beneficial in the treatment of isolated medial compartment KOA, via an assessment of patient-reported outcome measures (PROMs). (ii) To investigate the relationship between PROMs and radiographic parameters of knee joint orientation/alignment.

This longitudinal observational study assessed a total of 42 patients that had undergone UKA (n=23) or HTO (n=19) to treat isolated medial compartment KOA. The PROMs assessed, pre-operatively and 1-year post-operatively, consisted of the: self-administered comorbidity questionnaire; short form-12; oxford knee score; knee injury and osteoarthritis outcome score; and the EQ-5D-5L. The radiographic parameters of knee joint alignment/orientation assessed, pre-operatively and 8-weeks post-operatively, included the: hip-knee-ankle angle; mechanical axis deviation; and the angle of the Mikulicz line.

Statistical analysis demonstrated an overall significant (p<0.001), pre-operative to post-operative, improvement in the PROM scores of both groups. There were no significant differences in the post-operative PROM scores of the UKA and HTO group. Correlation analyses revealed that pre-operatively, a more distolaterally angled Mikulicz line was associated with worse knee function (p<0.05) and overall health (p<0.05); a relationship that, until now, has not been investigated nor commented upon within the literature.

UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with isolated medial compartment KOA. To further the scientific/medical community's understanding of the factors that impact upon health-outcomes in KOA, future research should seek to investigate the mechanism underlying the relationship, between Mikulicz line and PROMs, observed within the current study.

Introduction

Vascularized fibular grafting following tumor resection is an essential treatment option in limb salvage surgery. This study aimed to assess the surgical and oncological outcomes of patients treated in Denmark between 2010 and 2022.

Hip Osteoarthritis (HOA) is the most common joint disorder and a major cause of disability in the adult population, leading to total hip replacement (THR). Recently, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early OA in the non-dysplastic hip. FAI is a pathological mechanical process, caused by abnormalities of the acetabulum and/or femur leading to damage the soft tissue structures. FAI can determine chondro-labral damage and groin pain in young adults and can accelerate HOA progression in middle-aged adults.

The aim of the study was to determine if the presence of calcium crystal in synovial fluid (SF) at the time of FAI surgery affects the clinical outcomes to be used as diagnostic and predictive biomarker.

49 patients with FAI undergoing arthroscopy were enrolled after providing informed consent; 37 SFs were collected by arthrocentesis at the time of surgery and 35 analyzed (66% males), median age 35 years with standard deviation (SD) 9.7 and body mass index (BMI) 23.4 kg/m²; e SD 3.

At the time of surgery, chondral pathology using the Outerbridge score, labral pathology and macroscopic synovial pathology based on direct arthroscopic visualization were evaluated. Physical examination and clinical assessment using the Hip disability & Osteoarthritis Outcome Score (HOOS) were performed at the time of surgery and at 6 months of follow up. As positive controls of OA signs, SF samples were also collected from cohort of 15 patients with HOA undergoing THR and 12 were analysed.

45% FAI patients showed CAM deformity; 88% presented labral lesion or instability and 68% radiographic labral calcification. 4 patients out of 35 showed moderate radiographic signs of OA (Kellegren-Lawrence score = 3). Pre-operative HOOS median value was 61.3% (68.10-40.03) with interquartile range (IQR) of 75-25% and post-operative HOOS median value 90% with IQR 93.8-80.60. In both FAI and OA patients the calcium crystal level in SFs negatively correlated with glycosaminoglycan (component of the extracellular matrix) released, which is a marker of cartilage damage (Spearman rho=-0.601, p<0.001).

In FAI patients a worst articular function after surgery, measured with the HOOS questionnaire, was associated with both acetabular and femoral chondropathy and degenerative labral lesion. Moreover, radiographic labral calcification was also significantly associated with pain, worst articular function and labral lesion. Calcium crystal level in SFs was associated with labral lesions and OA signs.

We concluded that the levels of calcium crystals in FAI patients are correlated with joint damage, OA signs and worst post-operative outcome. The presence of calcium crystals in SF of FAI patients might be a potential new biomarker that might help clinicians to make an early diagnosis, evaluate disease progression and monitor treatment response.

Purpose

To compare postoperative clinical outcomes between posterior cruciate ligament (PCL) retaining and resecting total knee arthroplasty (TKA) using same cruciate-substituting (CS) inserts, and to elucidate the clinical relevance of the residual PCL in cruciate-retaining TKA, considering intraoperative influence factors, such as the posterior tibial slope, posterior condylar offset, joint gap, joint balance, and joint laxity.

Multiple biochemical biomarkers have been previously investigated for the diagnosis, prognosis and response to treatment of articular cartilage damage, including osteoarthritis (OA). Synovial fluid (SF) biomarker measurement is a potential method to predict treatment response and effectiveness. However, the significance of different biomarkers and their correlation to clinical outcomes remains unclear. This systematic review evaluated current SF biomarkers used in investigation of cartilage degeneration or regeneration in the knee joint and correlated these biomarkers with clinical outcomes following cartilage repair or regeneration interventions.

PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. Studies evaluating SF biomarkers and clinical outcomes following cartilage repair intervention were included. Two researchers independently performed data extraction and QUADAS-2 analysis. Biomarker inclusion, change following intervention and correlation with clinical outcome was compared.

9 studies were included. Study heterogeneity precluded meta-analysis. There was significant variation in sampling and analysis. 33 biomarkers were evaluated in addition to microRNA and catabolic/anabolic ratios. Five studies reported on correlation of biomarkers with six biomarkers significantly correlated with clinical outcomes following intervention. However, correlation was only demonstrated in isolated studies.

This review demonstrates significant difficulties in drawing conclusions regarding the importance of SF biomarkers based on the available literature. Improved standardisation for collection and analysis of SF samples is required. Future publications should also focus on clinical outcome scores and seek to correlate biomarkers with progression to further understand the significance of identified markers in a clinical context.

Patients with Paget's Disease of Bone (PDB) more frequently require total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, controversy remains regarding their outcome. This project aims to evaluate the current literature regarding outcomes following THA and TKA in PDB patients.

MEDLINE, EMBASE and Cochrane databases were searched on February 15th, 2022. Inclusion criteria comprised studies evaluating outcomes following THA/TKA in PDB patients. Quality of included studies was assessed using the Newcastle-Ottawa Scale.

19 articles (published between 1976–2022) were included, comprising 58,695 patients (48,766 controls and 10,018 PDB patients), from 209 potentially relevant titles. No study was of high quality. PDB patient pooled mortality was 32.5% at mean 7.8(0.1-20) years following THA and 31.0% at mean 8.5(2-20) years following TKA. PDB patient revision rate was 4.4% at mean 7.2(0-20) years following THA and 2.2% at mean 7.4(2-20) years following TKA. Renal complications, respiratory complications, heterotopic ossification, and surgical site infection were the most common medical and surgical complications.

The largest systematic review, to date, evaluating outcomes following THA and TKA in PDB patients. All functional outcome scores improved. PDB patient revision rate was comparable to UK National Joint Registry. However, there is a significant need for prospective matched case-control studies to robustly compare outcomes in PDB patients with unaffected counterparts.

Fragility ankles fractures in the geriatric population are challenging to manage, due to fracture instability, soft tissue compromise, patient co-morbidities. Traditional management options include open reduction internal fixation, or conservative treatment, both of which are fraught with high complication rates. We aimed to present functional outcomes of elderly patients with fragility ankle fractures treated with tibiotalocalcaneal nails.

171 patients received a tibiotalocalcaneal nail over a six-year period, but only twenty met the inclusion criteria of being over sixty and having poor bone stock, verified by radiological evidence of osteopenia or history of fragility fractures. Primary outcome was mortality risk from co-morbidities, according to the Charlson co-morbidity index (CCI), and patients’ post-operative mobility status compared to pre-operative mobility. Secondary outcomes include intra-operative and post-operative complications, six-month mortality rate, time to mobilisation and union.

The mean age was 77.82 years old, five of whom are type 2 diabetics. The average CCI was 5.05. Thirteen patients returned to their pre-operative mobility state. Patients with low CCI are more likely to return to pre-operative mobility status (p=0.16; OR=4.00).

Average time to bone union and mobilisation were 92.5 days and 7.63 days, respectively. Mean post-operative AOFAS ankle-hindfoot and Olerud-Molander scores were 53.0 (range 17-88) and 50.9 (range 20-85), respectively. There were four cases of broken distal locking screws, and four cases of superficial infection. Patients with high CCI were more likely to acquire superficial infections (p=0.264, OR=3.857). There were no deep infections, periprosthetic fractures, nail breakages, non-unions.

TTC nailing is an effective treatment methodology for low-demand geriatric patients with fragility ankle fractures. This technique leads to low complication rates and early mobilisation. It is not a life-changing procedure, with many able to return to their pre-operative mobility status, which is important for preventing the loss of socioeconomic independence.

Abstract

Robotic assistance in knee arthroplasty has become increasingly popular due to improved accuracy of prosthetic implantation. However, literature on the mid-term outcomes is limited especially that of hand-held robotic-assisted devices. We present one of the longest follow-up series to date using this novel technology and discuss the learning curve for introducing robotic technology into our practice.

The purpose of this single-surgeon study is to evaluate the survival, patient-reported outcomes and learning curve for handheld boundary-controlled robotic-assisted unicompartmental knee arthroplasties (HBRUKAs) at our hospital.

This retrospective study evaluates 100 cases (94 Medial, 6 Lateral) performed by a single surgeon between October 2012 and July 2018. 52% were males, mean age was 64.5y (range 47.3y-85.2y) and mean BMI was 31.3 (range 21.8–43). Both inlay (40%) and onlay (60%) designs were implanted. Patients were followed up routinely at 1 and 5 years with Oxford Knee Scores (OKS) recorded. The learning curve was determined by tourniquet times.

At a mean follow-up of 4.3 years (range 1.6y–7.3y), survivorship was 97%. There were three revisions: One case of aseptic loosening (1.5y), one case of deep-infection (3.8y) and one case of contralateral compartment osteoarthritis progression (5y). Mean 5-year OKS was 39.8. A 14.3% reduction in mean tourniquet times between the first 25 cases (105.5minutes) and subsequent cases (90.4minutes) was seen.

This single-surgeon study showed good survivorship and patient-reported outcomes for HBRUKAs at our hospital. A learning curve of approximately 25 cases was shown, with significant decreases in tourniquet times with respect to increased surgeon experience.

Orthopedic device-related infection (ODRI) preclinical models are widely used in translational research. Most models require induction of general anesthesia, which frequently results in hypothermia in rodents. This study aimed to evaluate the impact of peri anesthetic hypothermia in rodents on outcomes in preclinical orthopedic device-related infection studies.

A retrospective analysis of all rodents that underwent surgery under general anesthesia to induce an ODRI model with inoculation of Staphylococcus epidermidis between 2016 and 2020 was conducted. A one-way multivariate analysis of covariance was used to determine the fixed effect of peri anesthetic hypothermia (hypothermic defined as rectal temperature <35°C) on the combined harvested tissue and implant colonies forming unit counts, and having controlled for the study groups including treatments received duration of surgery and anesthesia and study period. All animal experiments were approved by relevant ethical committee.

A total of 127 rodents (102 rats and 25 mice) were enrolled in an ODRI and met the inclusion criteria. The mean lowest peri-anesthetic temperature was 35.3 ± 1.5 °C. The overall incidence of peri-anesthetic hypothermia was 41% and was less frequently reported in rats (34% in rats versus 68% in mice). Statistical analysis showed a significant effect of peri anesthetic hypothermia on the post-mortem combined colonies forming unit counts from the harvested tissue and implant(s) (p=0.01) when comparing normo- versus hypothermic rodents. Using Wilks’ Λ as a criterion to determine the contribution of independent variables to the model, peri-anesthetic hypothermia was the most significant, though still a weak predictor, of increased harvested colonies forming unit counts.

Altogether, the data corroborate the concept that bacterial colonization is affected by abnormal body temperature during general anesthesia at the time of bacterial inoculation in rodents, which needs to be taken into consideration to decrease infection data variability and improve experimental reproducibility.