Aims

Periprosthetic femoral fracture (PPF) is a major complication following total hip arthroplasty (THA). Uncemented femoral components are widely preferred in primary THA, but are associated with higher PPF risk than cemented components. Collared components have reduced PPF rates following uncemented primary THA compared to collarless components, while maintaining similar prosthetic designs. The purpose of this study was to analyze PPF rate between collarless and collared component designs in a consecutive cohort of posterior approach THAs performed by two high-volume surgeons.

The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA, the tibial cutting surface is decided parallel to the femoral cutting surface (or trial component) with in-line traction. These approaches are categorized as unrestricted KA because there is no consideration of leg alignment or component orientation. Restricted KA is an approach where the periarthritic joint surface is replicated within a safe range, due to concerns about extreme alignments that have been considered ‘alignment outliers’ in the neutral mechanical alignment approach. More recently, functional alignment and inverse kinematic alignment have been advocated, where bone cuts are made following intraoperative planning, using intraoperative measurements acquired with computer assistance to fulfill good coordination of soft-tissue balance and alignment. The KA-TKA approach aims to restore the patients’ own harmony of three knee elements (morphology, soft-tissue balance, and alignment) and eventually the patients’ own kinematics. The respective approaches start from different points corresponding to one of the elements, yet each aim for the same goal, although the existing implants and techniques have not yet perfectly fulfilled that goal

Introduction. This study aims to evaluate the effect of using different types of fixator on the quality of callus and complications during distraction osteogenesis in patients with achondroplasia. Materials and Methods. Forty-nine achondroplasia patients with a minimum follow-up of 36 months who underwent limb lengthening between 2005 and 2017 with external fixator only were included. Thirty-three of the patients underwent lengthening using classical Ilizarov frame, while spatial frame used for sixteen. Regenerate quality is evaluated according to the Li classification on the X-ray taken one month after the end of the distraction. Complications were noted in the follow-up period. Results. The mean age at the time of surgery was 8,6 years. The mean external fixation index (EFI) was 34,3 and 30,1 day/cm for spatial frame and Ilizarov frame respectively. Mean follow-up period of 161,62 months and mean fixator period of 257 days. Amount of lengthening was 7,2 cm for Ilizarov frame, and 7,5 cm for spatial frame. Rate of callus with good morphological quality seen at consolidation was 72,4% and 50% for Ilizarov and spatial frames respectively. Two groups show similar results of complication rates in terms of pin site infection, premature fibular consolidation, regenerate fracture, plastic deformation, knee contracture. However fibular nonunion rates were higher for Ilizarov-type fixator. Conclusions. Although spatial frame with computer assistance brings easier follow-up for deformity correction, Ilizarov-type external fixator show slightly higher rates of good quality callus during consolidation for patients with achondroplasia

Aims

The current study aimed to compare robotic arm-assisted (RA-THA), computer-assisted (CA-THA), and manual (M-THA) total hip arthroplasty regarding in-hospital metrics including length of stay (LOS), discharge disposition, in-hospital complications, and cost of RA-THA versus M-THA and CA-THA versus M-THA, as well as trends in use and uptake over a ten-year period, and future projections of uptake and use of RA-THA and CA-THA.

INTRODUCTION. Total knee arthroplasty (TKA) is considered a highly successful procedure. Survival rates of more than 90% after 10 years are generally reported. However, complications and revisions may still occur for many reasons, and some of them may be related to the operative technique. Computer assistance has been suggested to improve the accuracy of implantation of a TKA (Jenny 2005). Short term results are still controversial (Roberts 2015). However, few long term results have been documented (Song 2016). The present study was designed to evaluate the long-term (more than 10 years) results of a TKA which was routinely implanted with help of a non-image based navigation system. The 5- to 8-year of this specific TKA has already been documented (Jenny 2013). The hypothesis of this study will be that the 10 year survival rate of this TKA will be improved in comparison to historical papers when analyzing survival rates and knee function as evaluated by the Knee Society Score (KSS). MATERIAL AND METHODS. All patients operated on between 2001 and 2004 for implantation of a navigated TKA were eligible for this study. Usual demographic and peri-operative items have been record. All patients were prospectively followed with clinical and radiological examination. All patients were contacted after the 10 year follow-up for repeat clinical and radiological examination (KSS, Oxford knee questionnaire and knee plain X-rays). Patients who did not return were interviewed by phone call. For patients lost of follow-up, family or general practitioner was contacted to obtain relevant information about prosthesis survival. Survival curve was plotted according to Kaplan-Meier. RESULTS. 247 TKAs were implanted during the study time-frame. 225 cases had an optimal lower limb axis (HKA angle between 177° and 183°) after TKA (91%). Final follow-up (including death or revision) was obtained for 200 cases (81%). Clinical status after 10 years was obtained for 146 cases (59%) (KSS, 102 cases – Oxford questionnaire, 146 cases – radiologic evaluation, 94 cases). 4 prosthetic revisions were performed for mechanical reasons during the follow-up time (1%). The 10 year survival rate was 98%. The mean KSS was 188 points. The mean Oxford score was 55 points. No component was considered loose at the final radiographic evaluation. No polyethylene wear was detected at the final radiographic evaluation. DISCUSSION. This study confirms our initial hypothesis, namely quite satisfactory results of navigated implanted TKA after more than 10 years. Navigation, whose precision is no longer to be demonstrated, probably contributed to the quality of the results. A more consistent anatomical reconstruction and ligamentous balance of the knee should lead to more consistent survival of the TKA. Other authors did observe similar results (Baumbach 2016). However, superiority of navigated TKA in comparison to conventional implanted TKA is difficult to prove because of the subtle differences expected in mostly underpowered studies. Longer term follow-up may be required

Introduction

At a minimum 12 years follow-up the Authors performed a matched paired study between 2 groups: Bi-Unicompartimental (femoro-tibial) versus Total Knee Replacements, both navigated, they hypothesised that Bi-UKR guarantees a clinical score and patient satisfaction at least similar to TKR without differences in survivorship.

INTRODUCTION. Unicompartmental knee arthroplasty (UKA) is considered a highly successful procedure. However, complications and revisions may still occur, and some may be related to the operative technique. Computer assistance has been suggested to improve the accuracy of implantation of a UKA. The present study was designed to evaluate the long-term (more than 10 years) results of an UKA which was routinely implanted with help of a non-image based navigation system. MATERIAL AND METHODS. All patients operated on between 2004 and 2005 for implantation of a navigated UKA were included. Usual demographic and peri-operative items have been record. All patients were prospectively followed with clinical and radiological examination. All patients were contacted after the 10 year follow-up for repeat clinical and radiological examination (KSS, Oxford knee questionnaire and knee plain X-rays). Patients who did not return were interviewed by phone call. For patients lost of follow-up, family or general practitioner was contacted to obtain relevant information about prosthesis survival. Survival curve was plotted according to Kaplan-Meier. RESULTS. 57 UKAs were implanted during the study time-frame. Final follow-up (including death or revision) was obtained for 50 cases (88%). Clinical status after 10 years was obtained for 45 cases (80%). 4 prosthetic revisions were performed for mechanical reasons during the follow- up time (7%). The 10 year survival rate was 94%. No component was considered loose at the final radiographic evaluation. No polyethylene wear was detected at the final radiographic evaluation. DISCUSSION. This study confirms our initial hypothesis, namely quite satisfactory results of a navigated implanted UKA after more than 10 years. Navigation, whose precision is no longer to be demonstrated, probably contributed to the quality of the results. A more consistent anatomical reconstruction and ligamentous balance of the knee should lead to more consistent survival of the UKA. However, superiority of navigated UKA in comparison to conventional implanted UKA is difficult to prove because of the subtle differences expected in mostly underpowered studies. Longer term follow-up may be required

Objectives

To assess the accuracy of patient-specific instruments (PSIs) versus standard manual technique and the precision of computer-assisted planning and PSI-guided osteotomies in pelvic tumour resection.

The objective of this paper is to demonstrate the difference in post-operative complication rates between Computer-assisted surgery (CAS) and conventional techniques in spine surgery. Several studies have shown that the accuracy of pedicle screw placement significantly improves with use of CAS. Yet, few studies have compared the incidence of post-operative complications between CAS and conventional techniques.

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent posterior lumbar fusion from 2011 to 2013. Multivariate analysis was conducted to demonstrate the difference in post-operative complication rates between CAS and conventional techniques in spine surgery.

Out of 15,222 patients, 14,382 (95.1%) were operated with conventional techniques and 740 (4.90%) were operated with CAS. Multivariate analysis showed that patients in the CAS group had less odds to experience adverse events post-operatively (OR 0.57, P <0.001).

This paper examined the complications in lumbar spinal surgery with or without the use of CAS. These results suggest that CAS may provide a safer technique for implant placement in lumbar fusion surgeries.

Despite many new methods with preoperative or intra-operative assistance to improve the accuracy of leg alignment, traditional intramedullary (IM) method of bone cutting is still the most commonly used. Traditional TKR using IM guide has more outliers comparing to new computer aided methods, especially in bowing femur which is more prevalent in Asian population. And IM guide could not be used when there is a medullary bony pathology. Avoiding entrance of medullary cavity has been proposed as one of criteria of minimally invasive TKA. We have designed an extramedullary (EM) guide for the distal femoral bone cutting with millimeter to millimeter increment which is compatible with all posterior referencing instrumentation systems. With mechanical line as the guide line on long leg X-ray film taking with the knee and foot facing anteriorly, the amount of distal femoral bone cutting was measured and recorded on computer screen pre-operatively. During surgery, distal femoral cutting was performed using the EM cutting jig for coronal alignment adjustment tool and anterior femoral cortex and a guide post as sagittal alignment guide. We retrogratively compared the post-operation long leg X-ray film of two hundreds patients using IM or EM guides, the mechanical alignment of femoral components were measured in coronal and sagittal planes. The results showed no significant difference in distribution and the ratio of outliers. However, if the bowing of femur is more than 8 degree, the outlier is more in the IM group. We have applied this technique in 8 patients having medullary pathology including plates or nails in femur. All patients got good post-operative limb alignment without the needs of computer assistance device during surgery. In conclusion, the technique is easy and the instrument is simple. The operative time was not prolonged; the medullary cavity was not entered and compatible with the principle of MIS technique. In case of medullary cavity is obstructed, it is cost-effective by using our EM guide comparing to other methods such as CAOS or PSI

The use of robotics in arthroplasty surgery is expanding rapidly as improvements in the technology evolve. This article examines current evidence to justify the usage of robotics, as well as the future potential in this emerging field.

We report our experience of using a computer navigation system to aid resection of malignant musculoskeletal tumours of the pelvis and limbs and, where appropriate, their subsequent reconstruction. We also highlight circumstances in which navigation should be used with caution.

We resected a musculoskeletal tumour from 18 patients (15 male, three female, mean age of 30 years (13 to 75) using commercially available computer navigation software (Orthomap 3D) and assessed its impact on the accuracy of our surgery. Of nine pelvic tumours, three had a biological reconstruction with extracorporeal irradiation, four underwent endoprosthetic replacement (EPR) and two required no bony reconstruction. There were eight tumours of the bones of the limbs. Four diaphyseal tumours underwent biological reconstruction. Two patients with a sarcoma of the proximal femur and two with a sarcoma of the proximal humerus underwent extra-articular resection and, where appropriate, EPR. One soft-tissue sarcoma of the adductor compartment which involved the femur was resected and reconstructed using an EPR. Computer navigation was used to aid reconstruction in eight patients.

Histological examination of the resected specimens revealed tumour-free margins in all patients. Post-operative radiographs and CT showed that the resection and reconstruction had been carried out as planned in all patients where navigation was used. In two patients, computer navigation had to be abandoned and the operation was completed under CT and radiological control.

The use of computer navigation in musculoskeletal oncology allows accurate identification of the local anatomy and can define the extent of the tumour and proposed resection margins. Furthermore, it helps in reconstruction of limb length, rotation and overall alignment after resection of an appendicular tumour.

Cite this article: Bone Joint J 2015;97-B:258–64.

Introduction. Valgus knee deformity is associated especially with differences in anatomy between medial and lateral femoral condyles. Vertically smaller lateral condyle and more distally located medial condyle cause valgus deformity in extension. The anteroposterior dimensions of both condyles influence the knee axis in flexion. In a „true“ valgus knee there is a mismatch between both condyles in both the vertical and anteroposterior dimensions, the lateral condyle is generally smaller. In a „false“ valgus knee there is no mismatch between anteroposterior dimensions of both condyles, the knee axis changes from valgus into varus with increased degree of flexion and lateral soft tissue structures are that's why not so contracted as in „true“ valgus knee deformity, where the knee stays in valgus deviation during the whole range of motion. The aim of the study was to preoperatively identify and analyse patterns of passive movement of osteoarthritic valgus knees with imageless navigation system to optimise surgical approach and intra-operative tissue handling during subsequent total knee replacement (TKR) surgery. Material and Methods. TKR were prospectively performed in 50 valgus knees. Cases with severe bony destruction and enormous soft tissue laxity were excluded from the study. The kinematic navigation system used was OrthoPilot® (Aesculap, Tuttlingen, Germany). It is designed to produce a numerical output of varus/valgus deviation of the knee against the degree of flexion. Before skin incision for TKR surgery, active markers were attached percutaneusly to the femur and the tibia with bicortical screws to create two ‘rigid bodies’. After the registration process the kinematic analysis was performed by passive movement of the knee. The mechanical axis was recorded at 0°, 30°, 60°, 90°, and 120° of flexion. The valgus deformity persistent through the whole range of motion was called „true“ and the valgus deformity passing into varus with flexion was called „false“. In „true“ valgus knees the lateral approach according to Keblish was used, in „false“ valgus knees we used standard medial parapatellar approach. Results. The pre-operative valgus deformity in extension ranged from 13° to 4° (mean 7,8°). We observed „true“ valgus type deformity during passive range of movement in 34 cases (68 %) and „false“ type of kinematics in 16 cases (32 %). The average value of valgus deviation in extension in „true“ group was 7,9° (range, 13° to 4°) and in „false“ group 7,5° (range, 9° to 6°), without statistically significant difference. In the „true“ valgus deviation group the value of deformity gradually decreased with flexion in all cases. The mean difference between axis deviation in 0° and 120° of flexion was 5,5° (range, 10° to 1°) in this group. In the „false“ valgus group the varus deviation was observed either already in 60° of flexion or in most cases in 90° of flexion. The mean difference between axis deviation in 0° and 120° of flexion in this group was much more significant – 12,0° (range, 14° to 10°) – there was statistically significant difference between both groups. The mean time necessary for data collection before surgery was 6 minutes (range, 4 to 11 minutes); afterwards, tha navigation was used for TKR implantation. No complications were observed regarding to the navigation usage. Subsequently correct soft tissue balance was achieved in all TKRs using this method. Conclusions. Computer navigation assistance can easily and fast help to identify the character of valgus deformity („true“ or „false“) just before skin incision. In „true“ valgus deviation lateral structures (iliotibial band, vastus lateralis tendon, lateral collateral ligament, and the popliteus muscle) are tight and lateral approach according to Keblish may be necessary for appropriate release and soft tissue balancing during TKR surgery. Mostly used standard medial parapatellar approach is always sufficient in „false“ valgus knees. Computer navigation can help surgeon to choose the appropriate parapatellar approach (medial or lateral) just before the surgery without significant time lost

The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes’ disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis.

As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques.

Cite this article: Bone Joint J 2014;96-B:5–18.

INTRODUCTION. In computer-aided total knee arthroplasty (TKA), surgical navigation systems (SNS) allow accurate tibio-femoral joint (TFJ) prosthesis implantation only. Unfortunately, TKA alters also normal patello-femoral joint (PFJ) functioning. Particularly, without patellar resurfacing, PFJ kinematics is influenced by TFJ implantation; with resurfacing, this is further affected by patellar implantation. Patellar resurfacing is performed only by visual inspections and a simple calliper, i.e. without computer assistance. Patellar resurfacing and motion via patient-specific bone morphology had been assessed successfully in-vitro and in-vivo in pilot studies aimed at including these evaluations in traditional navigated TKA. The aim of this study was to report the current experiences in-vivo in two patient cohorts during TKA with patellar resurfacing. MATERIALS AND METHODS. Twenty patients with knee gonarthrosis were divided in two cohorts of ten subjects each and implanted with as many fixed-bearing posterior-stabilised prostheses (NRG® and Triathlon®, Stryker®-Orthopaedics, Mahwah, NJ-USA) with patellar resurfacing. Fifteen patients were implanted; five patients of the Triathlon cohort are awaiting hospital admission. TKAs were performed using two SNS (Stryker®-Leibinger, Freiburg-Germany). In addition to the traditional knee SNS (KSNS), the novel procedure implies the use of the patellar SNS (PSNS) equipped with a specially-designed patellar tracker. Standard navigated procedures for intact TFJ survey were performed using KSNS. These were performed also with PSNS together intact PFJ survey. Standard navigated procedures for TFJ implantation were performed using KSNS. During patellar resurfacing, the patellar cutting jig was fixed at the desired position with a plane probe into the saw-blade slot; PSNS captured tracker data to calculate bone cut level/orientation. After sawing, resection accuracy was assessed using a plane probe. TFJ/PFJ kinematics were captured with all three trial components in place for possible adjustments, and after final component cementing. A calliper and pre/post-TKA X-rays were used to check for patellar thickness/alignment. RESULTS. This protocol was performed successfully in TKAs, resulting in 30 min longer TKA. Final lower limb misalignment was within 0.5°, resurfaced patella was 0.4±1.2 mm thinner than the native, and patellar cut was 0.4°±4.1° laterally tilted. Final PFJ kinematics was taken within the reference normality in both series. PFJ flexion, tilt and medio-lateral shift range were 66.9°±8.5° (minimum÷maximum, 15.6°÷82.5°), 8.0°±3.1° (−5.3°÷2.8°), and 5.3±2.0 mm (−5.5÷0.2 mm), respectively. Significant (p<0.005) correlations were found between the internal/external rotation of the femoral component and PFJ tilt (R. 2. =0.41), and between the mechanical axis on the sagittal plane and PFJ flexion (R. 2. =0.44) and antero-posterior shift (R. 2. =0.45). Patellar implantation parameters were confirmed by X-ray inspections. Discrepancies in thickness up to 5 mm were observed between SNS- and calliper-based measurements. CONCLUSIONS. These results support relevance/efficacy of patellar tracking in in-vivo navigated TKA and may contribute to a more comprehensive assessment of the original whole knee, i.e. including also PFJ. Patellar preparation would be supported for suitable component positioning in case of resurfacing, but, conceptually, also in not-resurfacing if SNS does not reveal PFJ abnormalities., Using this procedure in the future, TFJ/PFJ abnormalities can be corrected intra-operatively by more cautious bone cut preparation and prosthetic positioning on the femur, tibia and patella

While double-bundle anterior cruciate ligament (ACL) reconstruction attempts to recreate the two-bundle anatomy of the native ACL, recent research also indicates that double-bundle reconstruction more closely reproduces the biomechanical properties of the ACL and restores the rotatory and sagittal stability to the level of the intact knee that was not attainable with anatomic single-bundle reconstruction. Though double-bundle reconstruction provides these potential biomechanical benefits, it poses a significant challenge to the surgeon who must attempt to accurately place twice as many tunnels while avoiding tunnel convergence compared to single-bundle reconstruction. In addition, previous work has shown that tunnel malpositioning may cause grafts that fail to reproduce the native biomechanics of the ACL, increase graft tension in deep knee flexion, increase anterior tibial translation, and produce lower IKDC (International Knee Documentation Committee) scores. We hypothesise that experienced surgeons without the use of computer-assisted navigation will place tunnels on the tibial plateau and lateral femoral condyle that more closely emulate the locations of the native anteromedial (AM) and posterolateral (PL) ACL bundles than inexperienced surgeons with the use of computer-assisted navigation. A novice surgeon group comprised of three medical students each performed double-bundle ACL reconstruction using passive computer-assisted navigation on a total of eleven cadaver knees. Their individual results were compared to three experienced orthopaedic surgeons each performing the identical procedure without the use of computer-assisted navigation on a total of nine cadaver knees. There were no significant differences in placement of either the AM or PL tunnels on the tibial plateau between novice surgeons using computer-assisted navigation and experienced surgeons without the use of computer navigation. On the lateral femoral condyle, novice surgeons placed the AM and PL tunnels significantly more anterior along Blumensaat's line on average compared to experienced surgeons. Both groups placed femoral AM and PL tunnels anterior to previously described AM and PL bundle positions. Novice surgeons utilizing computer-assisted navigation and experienced surgeons without computer assistance place the AM and PL tunnels on the tibial side with no significant difference. On the lateral femoral condyle, novice surgeons utilising computer-assisted navigation place tunnels significantly anterior along Blumensaat's line compared to experienced surgeons without the use of computer navigation