Applications of artificial intelligence and machine learning for the hip and knee surgeon: current state and implications for the future.

BACKGROUND: Artificial Intelligence (AI)/Machine Learning (ML) applications have been proven efficient to improve diagnosis, to stratify risk, and to predict outcomes in many respective medical specialties, including in orthopaedics. CHALLENGES AND DISCUSSION: Regarding hip and knee reconstruction surgery, AI/ML have not made it yet to clinical practice. In this review, we present sound AI/ML applications in the field of hip and knee degenerative disease and reconstruction. From osteoarthritis (OA) diagnosis and prediction of its advancement, clinical decision-making, identification of hip and knee implants to prediction of clinical outcome and complications following a reconstruction procedure of these joints, we report how AI/ML systems could facilitate data-driven personalized care for our patients.

A novel and secure technique of stemmed acetabular cup implantation in complex hip reconstructions: a comparative study and technical note.

PURPOSE: The stemmed acetabular cup (SAC) can be considered in several complicated situations. This type of prosthesis uses the iliac isthmus, which is most often preserved, thus allowing solid anchorage. Its implantation is prone to mechanical complications intraoperatively, such as extra-isthmic effraction, fracture, and early aseptic loosening. The aim of our study was to compare a new technique using a flexible motorized reamer combined with isthmus catheterization (Group A) versus the standard technique deploying a rigid reamer alone (Group B). MATERIALS AND METHODS: A retrospective analysis was carried out of the SACs implanted at our hospital. The main evaluation criterion was visualization of extra-isthmic effraction (EIE) of the stem. RESULTS: Fifty-six SACs (Integra Lepine®, Genay, France) were implanted, 31 in group A and 25 in group B. The mean follow-up was 21.6 months ± 22.3. This study found fewer EIEs using a flexible motorized reamer (0 versus 5, p = 0.014), less perioperative bleeding (p = 0.054), and less aseptic loosening in group A (p = 0.034). There was no difference in terms of infection or other mechanical complications post-operatively between the two groups. CONCLUSION: Using iliac catheterization combined with a flexible motorized reamer when implanting a SAC helps to avoid EIE and it also appears to reduce complications such as peri-operative bleeding and early aseptic loosening. We recommend use of this surgical technique rather than a rigid reamer alone, and this new technique should allow widespread and more accessible use of this specific type of implant.

Case of femoral pseudarthrosis due to Scedosporium apiospermum in an immunocompetent patient with successful conservative treatment and review of literature.

Scedosporium apiospermum is a ubiquitous filamentous fungus, commonly found in soil, sewage and polluted waters. It is rarely pathogenic but can cause a broad spectrum of clinical diseases, which can be localised or disseminate to distant organs. The disseminated form of the disease is mostly seen among immunocompromised patients. However, some rare cases of disseminated disease have been reported in immunocompetent individuals. Treatment of these infections is challenging because of their natural resistance to many antifungal agents. Here, we report the case of a 57-year-old immunocompetent patient diagnosed with femoral pseudarthrosis due to S. apiospermum, despite having no obvious clinical sign of infection. Previously, the patient had undergone four iterative femoral surgeries following a road traffic accident which occurred 20 years before. During its last surgery for pseudarthrosis, no clinical or biological signs of infection were present. Per operative samples tested positive for S. apiospermum. The patient was successfully treated with oral voriconazole during 6 months with an excellent tolerance. We also provide a review of literature on bone and joint infections due to Scedosporium spp. (S. apiospermum, Scedosporium boydii and Scedosporium aurantiacum), discussing the evolution of their management and outcome which seems to improve since the use of voriconazole.

Outcomes after revision of metal on metal hip resurfacing to total arthroplasty using the direct anterior approach.

BACKGROUND: Function after revision total hip arthroplasty (THA) in failed metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) is variable, but post-operative complication rates are reportedly high. We hypothesized HRA conversion to THA using the direct anterior approach (DAA) would be associated with optimal outcome. METHODS: Seventeen MoM-HRAs in 15 patients (seven males, eight females) were revised through the DAA. The mean age was 45 years (28-59 yrs). The most common indications for revision were aseptic loosening of the acetabular component or of the femoral component and femoral neck fracture. In 16 hips, a conversion to a ceramic-on-ceramic (CoC) (13 hips) or to a metal-on polyethylene (MOP) (2), or to a large-head MoM (1) THA was done. An isolated femoral revision was done in one hip. RESULTS: After 6.7 ± 3 years, no hip had required a re-revision. The Postel-Merle d'Aubigne (PMA) functional score improved from 9 (4-14) to 16 (12-18) (p < 0.001). An intra-operative fracture of the greater trochanter (one hip) and dysesthesia of the lateral femoral cutaneous nerve (four hips) were reported. Mean serum chromium concentration decreased from 33.2 µg/L (11.8-62 µg/L) pre-operatively to 5.8 µg/L (0.4-35.5 µg/L) post-operatively (p < 0.001), and mean serum cobalt concentration decreased from 35.8 µg/L (6.3-85.5 µg/L) to 4.7 µg/L (0.26-25.7 µg/L) (p = 0.003). CONCLUSION: Revision of failed MoM-HRA using the DAA resulted in an acceptable clinical outcome, no specific complication and no further surgery. A consistent decline in serum ion levels may be expected following HRA conversion to THA.

Fatty infiltration of stage 1 or higher significantly compromises long-term healing of supraspinatus repairs.

BACKGROUND: Fatty infiltration (FI) compromises outcomes of rotator cuff repairs. Most clinicians consider FI of the infraspinatus, whether it is torn or intact, because it is most rapidly affected. The purpose of this study was to report long-term outcomes of isolated supraspinatus repairs and to determine their associations with FI of the infraspinatus and supraspinatus. METHODS: The records of 182 patients who underwent repair of isolated supraspinatus tears and had preoperative magnetic resonance imaging were retrieved. Of these, 147 patients were evaluated at 10 years' follow-up using the Constant score and magnetic resonance imaging scans. RESULTS: Preoperative FI was greater in the supraspinatus (52% stage ≥1) than in the infraspinatus (29% stage ≥1). The 10-year Constant scores were influenced by FI of the supraspinatus (P = .006) but not of the infraspinatus (P = .422). Multivariable regression confirmed that Constant scores were significantly lower for female patients, repetitive work, and stage 1 and stage 2 FI of the supraspinatus in addition to open surgery. Retear rates (Sugaya types IV-V) were also influenced by FI of the supraspinatus (P = .001) but not of the infraspinatus (P = .979). Shoulders with supraspinatus FI at stages 0, 1, and 2 had retear rates of 10%, 22%, and 31%, respectively. Multivariable regression affirmed that the odds of retears are significantly increased by both stage 1 and stage 2 FI of the supraspinatus. CONCLUSIONS: The Constant scores and retear rates were significantly associated with FI of the torn supraspinatus (stage ≥1) but not of the intact infraspinatus. The authors recommend that rapid surgical intervention be considered, before accumulation of fat, especially for young, active patients.

Do Dual-Mobility Cups Reduce the Risk of Dislocation in Total Hip Arthroplasty for Fractured Neck of Femur in Patients Aged Older Than 75 Years?

BACKGROUND: Total hip arthroplasty (THA) for intracapsular neck of femur (NOF) fracture remains debatable as it is associated with higher rates of dislocation, notably in the older part of the population. We hypothesized this risk could be limited using dual-mobility cups (DMCs). METHODS: Eighty-two patients (83 hips) aged older than 75 years underwent DMC-THA using a posterolateral approach for an intracapsular NOF fracture. RESULTS: Clinical data were collected in 45 patients at a mean of 23.8 ± 9.4 months (12.1-42 months). The mortality rates were 19% (16 patients) and 36.5% (30 patients) at 1 year postoperatively and at the last follow-up, respectively. Postoperatively, there were 2 dislocations of the large articulation (4.4%) and one intraprosthetic dislocation (2.2%), all related to technical errors. Functional results were rated at least good in 71% cases, whereas the Parker and Devane scores were stable, indicating optimal restoration of autonomy and physical activity. CONCLUSION: Although technically demanding, DMC-THA may prevent dislocation in intracapsular NOF fracture in elderly patients, while consistently limiting the risk of loss of independence.

Direct subcutaneous injection of polyethylene particles over the murine calvaria results in dramatic osteolysis.

PURPOSE: The murine calvarial model has been widely employed for the in vivo study of particle-induced osteolysis, the most frequent cause of aseptic loosening of total joint replacements. Classically, this model uses an open surgical technique in which polyethylene (PE) particles are directly spread over the calvarium for the induction of osteolysis. We evaluated a minimally invasive modification of the calvarial model by using a direct subcutaneous injection of PE particles. METHODS: Polyethylene (PE) particles were injected subcutaneously over the calvaria of C57BL6J ten-week-old mice ("injection" group) or were implanted after surgical exposure of the calvaria ("open" group) (n = 5/group). For each group, five additional mice received no particles and served as controls. Particle-induced osteolysis was evaluated two weeks after the procedure using high-definition microCT imaging. RESULTS: Polyethylene particle injection over the calvaria resulted in a 40% ± 1.8% decrease in the bone volume fraction (BVF), compared to controls. Using the "open surgical technique", the BVF decreased by 16% ± 3.8% as compared to controls (p < 0.0001). CONCLUSIONS: Direct subcutaneous injection of PE particles over the murine calvaria produced more profound resorption of bone. Polyethylene particle implantation by injection is less invasive and reliably induces osteolysis to a greater degree than the open technique. This subcutaneous injection method will prove useful for repetitive injections of particles, and the assessment of potential local or systemic therapies.

No Difference in Dislocation Rates Comparing DMC-THA for Displaced Femoral Neck Fracture and for Osteoarthritis-A Matched-Pair Analysis.

Background: We hypothesized the risk of prosthetic instability would be similar in patients treated for femoral neck fracture (FNF) comparatively to patients treated for osteoarthritis (OA) using a dual-mobility cup-total hip arthroplasty (DMC-THA). Methods: One hundred and nine patients (109 hips), with a mean age of 69.6 ± 3 years (65-75 years), underwent DMC-THA using a posterolateral approach for a FNF (study group). Patients were matched for age and sex with 109 OA patients treated by the same procedure (control). Results: Postoperatively, there were four dislocations of the large articulation in the study group, and none in the control (p = 0.12). Periprosthetic joint infection (PJI) was the most common surgical complication and was more frequent in the study group. Postoperatively, functional results were at least good in > 90% patients in both groups. At the last follow-up, patients in the study group had recovered autonomy and physical activity comparable to those of the preoperative period. Conclusion: We found no increased risk of dislocation after DMC-THA using a posterolateral approach for FNF as compared to the same procedure for OA. In this study, function and independence were restored postoperatively in the vast majority of patients. DMC-THA appears as a viable therapeutic option in autonomous patients with a displaced FNF.

Does open repair of anterosuperior rotator cuff tear prevent muscular atrophy and fatty infiltration?

BACKGROUND: Repair of cuff tears involving rotator interval reportedly improves function. However, it is unclear whether successful repair prevents shoulder degenerative changes. QUESTIONS/PURPOSES: Therefore, we (1) documented the minimal 4-year function of patients who underwent open surgical repair for rotator interval tears; (2) evaluated repaired tendon healing with postoperative MRI; and (3) sought to determine the influence of tendon healing on muscular and glenohumeral joint changes. METHODS: We retrospectively analyzed 22 patients (23 shoulders) treated by open transosseous reinsertion of supraspinatus and subscapularis tendons. The mean age of the patients was 53 years (range, 37-64 years). The tear was traumatic in four cases. Repair healing and muscular changes were assessed using MRI. The minimum followup was 46 months (mean, 75 months; range, 46-103 months). RESULTS: We observed an improvement in the absolute Constant-Murley score from 63 points preoperatively to 76 points postoperatively. With the last followup MRI, the supraspinatus tendon repair had failed in two of the 23 shoulders, whereas the subscapularis tendon repair had healed in all cases. Once healing of the repaired tendon occurred, supraspinatus muscle atrophy never worsened. However, on MRI fatty infiltration of the rotator cuff muscles increased despite successful tendon repair. Glenohumeral arthritis remained stable. Postoperative abduction and internal rotation strengths were better when the standardized supraspinatus muscle area was greater than 0.5 at the final evaluation. CONCLUSION: Durable functional improvement and limited degenerative articular and muscular changes can be expected in most patients 4 to 10 years after open repair of anterosuperior cuff tears provided that healing of the cuff is obtained. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

MRI Bone Abnormality of the Knee following Ultrasound Therapy: Case Report and Short Review.

Ultrasound (US) therapy in sports and medical pathologies is widely used by many physiotherapists and sports medicine clinicians; however, data regarding their potential side effects remain rare. We report a case of a 21-year-old woman with iliotibial band (ITB) syndrome treated with a physiotherapy session combined with US therapy. She had twenty 7 min US sessions on the knee, for 3 months (US at 1 Mhz with an intensity between 1 and 2 W/cm2). Due to persistence of the ITB syndrome's symptomatology after the 3 months of physiotherapy sessions, an MRI (magnetic resonance imaging) was carried out and revealed osteonecrosis-like bone abnormalities on the external femoral condyle, the external tibial plateau, and the proximal fibula. In view of these lesions, the ultrasonic therapy was stopped, and a repeat MRI demonstrated the progressive disappearance of these imaging abnormalities one year after the last US (ultrasound) treatment. In light of this case, we propose here a short review of reported osseous "osteonecrosis" abnormalities associated with US therapies.

Targeted resequencing of the 13q13 spondyloarthritis-linked locus identifies a rare variant in FREM2 possibly associated with familial spondyloarthritis.

OBJECTIVES: The strong heritability of spondyloarthritis remains poorly explained, despite several large-scale association studies. A recent linkage analysis identified a new region linked to SpA on 13q13. Here we searched for variants potentially explaining this linkage signal by deep-sequencing of the region. METHODS: Re-sequencing of the 1.4 Mb target interval was performed in 92 subjects from the 43 best-linked multicases families (71 spondyloarthritis and 21 unaffected relatives), using hybridization capture-based protocol (Illumina Nextera®). Variants of interest were then genotyped by TaqMan and high resolution melting to check their co-segregation with disease in the same families and to test their association with spondyloarthritis in an independent cohort of 1,091 unrelated cases and 399 controls. Expression of FREM2 was assessed by immunostaining. RESULTS: Of the 7,563 variants identified, 24 were non-synonymous coding single-nucleotide variants. Two of them were located in the FREM2 gene on a haplotype co-segregating with the disease, including one common variant (R1840W, minor allele frequency=0.11) and one rare variant (R727H, minor allele frequency=0.0001). In the case-control analysis, there was no significant association between R1840W and spondyloarthritis (P-value=0.21), whereas R727H was not detected in any of the genotyped individuals. Immunostaining experiments revealed that FREM2 is expressed in synovial membrane, cartilage and colon. CONCLUSIONS: Targeted re-sequencing of a spondyloarthritis-linked region allowed us to identify a rare non-synonymous coding variant in FREM2, co-segregating with spondyloarthritis in a large family. This gene is expressed in several tissues relevant to spondyloarthritis pathogenesis, supporting its putative implication in spondyloarthritis.

Cup loosening after cemented Metasul® total hip replacement: a retrieval analysis.

Small-diameter cemented Metasul® cups have been previously identified to be at high risk of early loosening. We asked whether this particular mode of failure was associated with a specific histological feature. Periprosthetic tissues were obtained at the time of revision of two aseptically loose cemented Metasul® cups. Each tissue sample was processed for routine histological analysis. A slight metallosis was visible microscopically in all tissue samples. Metallic wear-debris particles were present both extracellularly and within the cytoplasm of macrophages. We noted a perivascular infiltration of lymphocytes accompanied by mature plasma cells. Our observations are compatible with the hypersensitivity-like reaction previously reported, described as an aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). Although wear was within normal reported range limits, this tissue reaction appeared as a consequence of continuous release of metallic ions from the prosthetic articulation. We hypothesise that ALVAL was involved in acetabular component failure, although acetabular loosening may have been initiated by high mechanical stress.

Fracture Risk of Long Bone Metastases: A Review of Current and New Decision-Making Tools for Prophylactic Surgery.

Long bone pathological fractures very much reflect bone metastases morbidity in many types of cancer. Bearing in mind that they not only compromise patient function but also survival, identifying impending fractures before the actual event is one of the main concerns for tumor boards. Indeed, timely prophylactic surgery has been demonstrated to increase patient quality of life as well as survival. However, early surgery for long bone metastases remains controversial as the current fracture risk assessment tools lack accuracy. This review first focuses on the gold standard Mirels rating system. It then explores other unique imaging thresholds such as axial or circumferential cortical involvement and the merits of nuclear imaging tools. To overcome the lack of specificity, other fracture prediction strategies have focused on biomechanical models based on quantitative computed tomography (CT): computed tomography rigidity analysis (CT-RA) and finite element analysis (CT-FEA). Despite their higher specificities in impending fracture assessment, their limited availability, along with a need for standardization, have limited their use in everyday practice. Currently, the prediction of long bone pathologic fractures is a multifactorial process. In this regard, machine learning could potentially be of value by taking into account clinical survival prediction as well as clinical and improved CT-RA/FEA data.

Rotationplasty Salvage Procedure as an Effective Alternative to Femoral Amputation in an Adult With a History of Osteosarcoma: A Case Report and Review.

Rotationplasty or Borggreve-Van Ness surgery is lower limb salvage surgery, indicated mainly in the management of femoral bone sarcoma and congenital femur malformations in children. It can also be an interesting surgery option for managing chronic osteoarticular infections, or in cases of non union when curative therapy is no longer an option, as an alternative to femoral amputation. The principle of this surgery is to remove the affected knee and to apply a rotation of 180° to the distal part of the lower limb in order to give the ankle the function of a neo-knee. With the help of an adapted prosthesis, the aim is to allow patients to resume their social and professional activities by keeping most of their lower limb, thus avoiding the known complications of amputation (ghost limb pain, proprioceptive deficit, psychological disorders). Nevertheless, this surgery is complex and exceptional, with vascular, infectious, and psychological risks - the chimeric aspect of the lower limb may cause significant ill-being for the patient. This article reports the case of a 38-year-old patient consulting for management of a complex septic distal femoral non-union following osteosarcoma considered as being in remission. The patient underwent rotationplasty surgery on his left lower limb, with very good functional results and no surgical revision to date. In light of this particular case, we propose a didactic overview of the literature data concerning this surgery, especially in adulthood.

Treatment of bone and joint infections by ceftazidime/avibactam and ceftolozane/tazobactam: a cohort study.

OBJECTIVES: Ceftazidime/avibactam (C/A) and ceftolozane/tazobactam (C/T) are two novel antibacterials with known efficacy against Gram-negative bacteria (GNB). We aimed to describe the efficacy and safety of surgical management combined with C/A or C/T treatment for bone and joint infections (BJIs). METHODS: We conducted an observational, bicentric study of patients treated with C/A or C/T for a BJI between May 2016 and June 2019. Failure was defined as the need for unplanned additional antibiotic treatment or orthopaedic surgery, or death due to the BJI up to the patient's latest visit. RESULTS: Overall, 15 patients were included. Nine patients were treated with C/A, mainly for polymicrobial BJI due to multidrug-resistant (MDR) bacteria (Enterobacteriaceae, n = 7). Six patients were male, the median age was 66 years and the median Charlson comorbidity index (CCI) was 5. It was the first septic episode at the site in 3/9 patients. The cure rate was 7/9 (median follow-up, 272 days). Two patients showed C/A-related confusion. Five patients were treated with C/T for BJI involving MDR Pseudomonas aeruginosa. Four patients were male, the median age was 53 years and the median CCI was 2. All patients had previous septic episodes at the infection site. The cure rate was 3/5 (median follow-up, 350 days). One patient was successfully treated by C/T then C/A for multistage spondylodiscitis. CONCLUSION: In our experience, C/A and C/T are two effective and safe options, even as salvage treatment for BJI due to MDR-GNB despite the absence of label, however more data are warranted.

A Short-Course Antibiotic Prophylaxis Is Associated with Limited Antibiotic Resistance Emergence in Post-Operative Infection of Pelvic Primary Bone Tumor Resection.

Resections of primary pelvic bone tumors are frequently complicated by surgical site infections (SSIs), thereby impairing the functional prognosis of patients, especially in case of implant removal. Although prophylactic antibiotics play an essential role in preventing SSIs, there are presently no recommendations that support their appropriate use. This study aimed to assess the impact of a 24 h prophylactic protocol on the bacterial ecology, the resistance pattern, and the SSI healing rate. We hypothesized that this protocol not only limits the emergence of resistance but also results in a good cure rate with implant retention in case of SSI. A retrospective study was performed that included all patients with an SSI following a pelvic bone tumoral resection between 2005 and 2017 who received a 24 h antibiotic prophylaxis protocol. Twenty-nine patients with an SSI were included. We observed a 75.9% rate of polymicrobial infection, with a high prevalence of digestive flora microorganisms and a majority of wild-type phenotypes. We confirmed that there was no significant emergence of resistant flora. After first-line debridement, antibiotics (DA) if any implant was used, or debridement, antibiotics, and implant retention (DAIR) whenever possible, we obtained a 79.3% cure rate, with implant removal in 20% of cases. The absence of an implant was significantly associated with SSI healing. Early infection management and low resistance profiles may also have a positive effect, but this needs to be confirmed in a larger cohort. In light of this, the use of a 24 h prophylactic protocol in primary pelvic bone tumor resections is associated with a favorable infection cure rate and implant retention in case of SSI, and minimal selection of resistant microorganisms.

Perioperative complications and causes of 30- and 90-day readmission after direct anterior approach primary total hip arthroplasty.

We aimed to report causes of readmission 30 and 90 days following a total hip arthroplasty (THA) using the direct anterior approach (DAA). METHODS: Three hundred and two patients (335 hips) underwent a DAA-THA for primary osteoarthritis. RESULTS: The main reasons for 30 and 90-day readmission were wound related problems, dislocation (rate: 0.9%) and deep infection. The readmission rates at 30 and 90 days were 1.8% and 2.7%, respectively. Age over 60 years and morbidly obese patients were at risk for complications. CONCLUSION: The DAA-THA was associated with low readmission rates. Obesity should be adressed preoperatively.