J. R. T. Pietrzak

The learning curve associated with robotic-arm assisted unicompartmental knee arthroplasty

Aims The primary aim of this study was to determine the surgical teams learning curve for introducing robotic‐arm assisted unicompartmental knee arthroplasty (UKA) into routine surgical practice. The secondary objective was to compare accuracy of implant positioning in conventional jig‐based UKA versus robotic‐arm assisted UKA. Patients and Methods This prospective single‐surgeon cohort study included 60 consecutive conventional jigbased UKAs compared with 60 consecutive robotic‐arm assisted UKAs for medial compartment knee osteoarthritis. Patients undergoing conventional UKA and robotic‐arm assisted UKA were well‐matched for baseline characteristics including a mean age of 65.5 years (SD 6.8) vs 64.1 years (SD 8.7), (p = 0.31); a mean body mass index of 27.2 kg.m2 (SD 2.7) vs 28.1 kg.m2 (SD 4.5), (p = 0.25); and gender (27 males: 33 females vs 26 males: 34 females, p = 0.85). Surrogate measures of the learning curve were prospectively collected. These included operative times, the Spielberger State‐Trait Anxiety Inventory (STAI) questionnaire to assess preoperative stress levels amongst the surgical team, accuracy of implant positioning, limb alignment, and postoperative complications. Results Robotic‐arm assisted UKA was associated with a learning curve of six cases for operating time (p < 0.001) and surgical team confidence levels (p < 0.001). Cumulative robotic experience did not affect accuracy of implant positioning (p = 0.52), posterior condylar offset ratio (p = 0.71), posterior tibial slope (p = 0.68), native joint line preservation (p = 0.55), and postoperative limb alignment (p = 0.65). Robotic‐arm assisted UKA improved accuracy of femoral (p < 0.001) and tibial (p < 0.001) implant positioning with no additional risk of postoperative complications compared to conventional jig‐based UKA. Conclusion Robotic‐arm assisted UKA was associated with a learning curve of six cases for operating time and surgical team confidence levels but no learning curve for accuracy of implant positioning. Cite this article: Bone Joint J 2018;100‐B:1033–42.

Iatrogenic Bone and Soft Tissue Trauma in Robotic-Arm Assisted Total Knee Arthroplasty Compared With Conventional Jig-Based Total Knee Arthroplasty: A Prospective Cohort Study and Validation of a New Classification System

BACKGROUNDnThe objective of this study was to compare macroscopic bone and soft tissue injury between robotic-arm assisted total knee arthroplasty (RA-TKA) and conventional jig-based total knee arthroplasty (CJ-TKA) and create a validated classification system for reporting iatrogenic bone and periarticular soft tissue injury after TKA.nnnMETHODSnThis study included 30 consecutive CJ-TKAs followed by 30 consecutive RA-TKAs performed by a single surgeon. Intraoperative photographs of the femur, tibia, and periarticular soft tissues were taken before implantation of prostheses. Using these outcomes, the macroscopic soft tissue injury (MASTI) classification system was developed to grade iatrogenic bone and soft tissue injuries. Interobserver and Intraobserver validity of the proposed classification system was assessed.nnnRESULTSnPatients undergoing RA-TKA had reduced medial soft tissue injury in both passively correctible (P < .05) and noncorrectible varus deformities (P < .05); more pristine femoral (P < .05) and tibial (Pxa0<xa0.05) bone resection cuts; and improved MASTI scores compared to CJ-TKA (P < .05). There was high interobserver (intraclass correlation coefficient 0.92 [95% confidence interval: 0.88-0.96], P < .05) andxa0intraobserver agreement (intraclass correlation coefficient 0.94 [95% confidence interval: 0.92-0.97], P < .05) of the proposed MASTI classification system.nnnCONCLUSIONnThere is reduced bone and periarticular soft tissue injury in patients undergoing RA-TKA compared to CJ-TKA. The proposed MASTI classification system is a reproducible grading scheme for describing iatrogenic bone and soft tissue injury in TKA.nnnCLINICAL RELEVANCEnRA-TKA is associated with reduced bone and soft tissue injury compared with conventional jig-based TKA. The proposed MASTI classification may facilitate further research correlating macroscopic soft tissue injury during TKA to long-term clinical and functional outcomes.

Prevention of limb length discrepancy in total hip arthroplasty

Total hip arthroplasty is a highly effective and cost-efficient procedure but postoperative limb length discrepancy is a common source of patient dissatisfaction and litigation. This article provides a systematic, stepwise approach for identifying and proactively managing risk factors associated with limb length discrepancy following total hip arthroplasty. This review explores preoperative history taking, clinical examination, radiological templating, implant positioning, soft tissue balancing, and intraoperative surgical techniques for minimizing leg length discrepancy while maintaining stability and restoring mechanical function following total hip arthroplasty. A comprehensive understanding of the multifactorial nature and methods for reducing postoperative limb length discrepancy is essential for optimizing patient satisfaction, clinical outcomes and long-term function following total hip arthroplasty.

Preoperative CT-Based Three-Dimensional Templating in Robot-Assisted Total Knee Arthroplasty More Accurately Predicts Implant Sizes than Two-Dimensional Templating

Patient dissatisfaction after total knee arthroplasty (TKA) is a concern. Surgical error is a common, avoidable cause of failed TKA. Correct femoral and tibial component sizing improves implant longevity, clinical outcomes, knee balance, and pain scores. We hypothesized that preoperative three-dimensional (3D) templating for robot-assisted TKA (RA-TKA) is more accurate than two-dimensional (2D) digital templating. Prospectively collected data from 31 RA-TKAs were assessed to determine accuracy pertaining to implant sizing and positioning. All cases undergoing RA-TKA undergo preoperative CT-scans as per protocol. Three blinded observers retrospectively templated these knees for TKA using standard radiographs. We compared whether 2D templating was as accurate as CT-guided templating. Postoperative radiographs were then evaluated for sizing and positioning. Intraclass correlation coefficients (ICCs) and the effect of learning curve were assessed. Preoperative femoral component 3D templating and retrospective blinded 2D templating accuracies were 96.6% and 52.9%, respectively (χ2: 17.965; odds ratio [OR]: 24.957, 3.250-191.661; pu2009<u20090.001). Tibial component 3D and 2D templating accuracies were 93.1% and 28.7%, respectively (χ2: 36.436; OR: 33.480, 7.400-151.481; pu2009<u20090.001). ICC for the three radiograph observers was 0.920 (95% confidence interval [CI]: 0.652-0.890; pu2009<u20090.001) for the femur and 0.833 (0.717-0.911; pu2009<u20090.001) for the tibia, showing excellent agreement. We conclude that preoperative CT-based templating for RA-TKA more accurately predicts the size of implants compared with traditional 2D digital templating. This may improve operating room efficiency and cost containment.

Robotic-arm assisted total knee arthroplasty is associated with improved early functional recovery and reduced time to hospital discharge compared with conventional jig-based total knee arthroplasty.

Aims The objective of this study was to compare early postoperative functional outcomes and time to hospital discharge between conventional jig‐based total knee arthroplasty (TKA) and robotic‐arm assisted TKA. Patients and Methods This prospective cohort study included 40 consecutive patients undergoing conventional jig‐based TKA followed by 40 consecutive patients receiving robotic‐arm assisted TKA. All surgical procedures were performed by a single surgeon using the medial parapatellar approach with identical implant designs and standardized postoperative inpatient rehabilitation. Inpatient functional outcomes and time to hospital discharge were collected in all study patients. Results There were no systematic differences in baseline characteristics between the conventional jig‐based TKA and robotic‐arm assisted TKA treatment groups with respect to age (p = 0.32), gender (p = 0.50), body mass index (p = 0.17), American Society of Anesthesiologists score (p = 0.88), and preoperative haemoglobin level (p = 0.82). Robotic‐arm assisted TKA was associated with reduced postoperative pain (p < 0.001), decreased analgesia requirements (p < 0.001), decreased reduction in postoperative haemoglobin levels (p < 0.001), shorter time to straight leg raise (p < 0.001), decreased number of physiotherapy sessions (p < 0.001) and improved maximum knee flexion at discharge (p < 0.001) compared with conventional jig‐based TKA. Median time to hospital discharge in robotic‐arm assisted TKA was 77 hours (interquartile range (IQR) 74 to 81) compared with 105 hours (IQR 98 to 126) in conventional jig‐based TKA (p < 0.001). Conclusion Robotic‐arm assisted TKA was associated with decreased pain, improved early functional recovery and reduced time to hospital discharge compared with conventional jig‐based TKA.

The Role of One-Stage Exchange for Prosthetic Joint Infection

Purpose of ReviewIn an era of increasing numbers of hip and knee replacements, strategies to manage prosthetic joint infection (PJI) that are effective at infection control with good patient-reported outcomes and cost containment for health systems are needed. Interest in single-stage exchange for PJI is rising and we assess evidence from the last 5xa0years related to this treatment strategy.Recent FindingsOnly five series for total knee replacement and ten series for total hip replacement have been reported in the last five years. More review articles and opinion pieces have been written. Reinfection rates in these recent studies range from 0 to 65%, but a meta-analysis and systematic review of all studies showed a reinfection rate of 7.6% (95% CI 3.4–13.1) and 8.8% (95% CI 7.2–10.6) for single-stage and two-stage revisions respectively. There is emerging evidence to support single-stage revision in the setting of significant bony deficiency and atypical PJIs such as fungal infections.SummaryProspective randomised studies are recruiting and are necessary to guide the direction of single-stage revision selection criteria. The onus of surgical excellence in mechanical removal of implants, necrotic tissue, and biofilms lies with the arthroplasty surgeon and must remain the cornerstone of treatment. Single-stage revision may be considered the first-line treatment for all PJIs unless the organism is unknown, the patient is systemically septic, or there is a poor tissue envelope.

Proximal hamstring tendinopathy: pathophysiology, diagnosis and treatment

Proximal hamstring tendinopathy is a chronic degenerative disease associated with progressive morbidity and functional decline. There is a growing incidence of the disease process but diagnosis is commonly delayed as patients present with vague and indolent symptoms, often without a specific precipitating injury. Treatment is also challenging as the existing literature varies in the nomenclature used for proximal hamstring tendinopathy and clinical trials use different management protocols with variable follow-up times. This review explores the existing literature on proximal hamstring tendinopathy and discusses the relevant anatomy, pathology, medical history, differential diagnosis, clinical assessment, diagnostic imaging and treatment of patients with proximal hamstring tendinopathy. This structured approach to proximal hamstring tendinopathy will enable clinicians to better understand the pathophysiology of the disease process, improve referrals to diagnostic imaging, and follow a stepwise approach to medical treatment and surgical referral.

Treatment of limb length discrepancy following total hip arthroplasty

Limb length discrepancy is the leading cause of patient dissatisfaction following total hip arthroplasty and the most common reason for litigation in the field of orthopaedics. This article provides a systematic, stepwise approach for identifying the aetiology of limb length discrepancy following total hip arthroplasty and provides guidance on the treatment of this complication to optimize postoperative clinical and functional outcomes. This review discusses postoperative history taking, clinical examination, radiographic assessment, conservative treatment, and surgical intervention for the management of patients with established limb length discrepancy following total hip arthroplasty. A comprehensive understanding of the multifactorial nature and methods of managing postoperative limb length discrepancy is essential for optimizing patient satisfaction, clinical outcomes and long-term function following total hip arthroplasty.