BACKGROUND:Manual compartment palpation is used as a component of the clinical diagnosis of acute compartment syndrome (ACS), particularly in obtunded patients. However, its utility and accuracy in the upper limb are unknown. The purposes of this study were to assess the accuracy of manual compartment palpation of ACS in the forearm in a cadaveric model and to assess the role of clinician experience in this setting. METHODS:Reproducible, sustained elevation of intracompartmental pressure was established in 8 fresh upper-limb cadaveric specimens. The 3 forearm compartments (volar, dorsal, and mobile wad) were randomized to pressures of 20 and 40 mm Hg (negative controls) and 60 and 80 mm Hg (ACS). This was achieved by using fluid infusion and a pressure monitoring system. Orthopaedic clinicians with varying experience (residents, registrars, and consultants) used palpation to assess forearm compartments with known intracompartmental pressures. The examiners were blinded to the compartment pressures and the other examiners' responses. After the examination, the following 3 questions were answered: (1) Was compartment syndrome present? (2) In which compartment(s) was the pressure elevated? (3) What would be the next management step (fasciotomy or observation)? RESULTS:Manual palpation of compartment pressure had an overall sensitivity of 70%, a specificity of 56%, a positive predictive value of 24%, a negative predictive value of 90%, and a likelihood ratio (LR) of 20.3 (p < 0.001). The sensitivity was similar in detecting ACS in the volar and dorsal compartments (70% and 69%, respectively). The sensitivity and specificity of combined volar and dorsal compartment palpation were 81% and 64% (LR, 16.6; p < 0.001) when performed by residents, 72% and 46% (LR, 4.2; p = 0.040) when performed by registrars, and 58% and 63% (LR, 3.6; p = 0.057) when performed by consultants. All of the compartments that were deemed positive for ACS were recommended for fasciotomy. CONCLUSIONS:In our study, manual palpation of compartment pressure had a low accuracy in the diagnosis of ACS of the forearm and was not improved by clinician experience. CLINICAL RELEVANCE:We recommend against the use of manual palpation of compartment pressure in the diagnosis of forearm ACS in an obtunded patient.

Hypothesis: Simple transverse or short oblique olecranon fractures without articular comminution are classified as Mayo type HA fractures and are typically treated with a tension band wire construct. Because of the high reoperation rates, frequently because of prominent hardware, all-suture tension band constructs have been introduced. It was the purpose to compare the biomechanical performance of conventional tension band wire fixation with a new all-suture tension band tape fixation for simple olecranon fractures. Methods: Mayo type HA olecranon fractures were created in 20 cadaveric elbows from 10 donors. One elbow of each donor was randomly assigned to the tension band wire technique (group TBW) or tension band tape (Arthrex, 1.3-mm SutureTape) technique (group TBT). Both groups were cyclically loaded with 500 N over 500 cycles, after which a uniaxial displacement was performed to evaluate load to failure. Data were analyzed for gap formation after cyclic loading, construct stiffness, and ultimate load to failure, where failure was defined as fracture gap formation greater than 4.0 mm. Results: There was no significant difference in gap formation after 500 cycles between the TBW (1.8 mm +/- 1.3 mm) and the TBT (1.9 mm +/- 1.1 mm) groups (P = .854). The TBT showed a tendency toward greater construct stiffness compared with the TBW construct (mean difference: 142 Mum; P = .053). Ultimate load to failure was not significantly different comparing both groups (TBW: 1138 N +/- 1286 N vs. TBT: 1126 N +/- 272 N; P = .928). In both groups, all repairs failed because of >4.0-mm gap formation at the fracture site and none because of tension band construct breakage. Conclusions: Our study shows that the TBT technique produces equivalent or superior biomechanical performance to the TBW for simple olecranon fractures. The TBT approach reduces the risk of hardware prominence and as a result mitigates against the need for hardware removal. The TBT technique offers a clinically viable alternative to TBW. (C) 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.

Background: Acromial and scapular spine fractures after reverse total shoulder arthroplasty (RTSA) can be devastating complications leading to substantial functional impairments. The purpose of this study was to review factors associated with increased acromial and scapular spine strain after RTSA from a biomechanical standpoint. Methods: A systematic review of the literature was conducted based on PRISMA guidelines. PubMed, Embase, OVID Medline, and CENTRAL databases were searched and strict inclusion and exclusion criteria were applied. Each article was assessed using the modified Downs and Black checklist to appraise the quality of included studies. Study selection, extraction of data, and assessment of methodological quality were carried out independently by two of the authors. Only biomechanical studies were considered. Results: Six biomechanical studies evaluated factors associated with increased acromial and scapular spine strain and stress. Significant increases in acromial and scapular spine strain were found with increasing lateralization of the glenosphere in four of the included studies. In two studies, glenosphere inferiorization consistently reduced acromial strain. The results concerning humeral lateralization were variable between four studies. Humeral component neck-shaft angle had no significant effect on acromial strain as analysed in one study. One study showed that scapular spine strain was significantly increased with a more posteriorly oriented acromion (55° vs. 43°; p < 0.001). Another study showed that the transection of the coracoacromial ligament increased scapular spine strain in all abduction angles (p < 0.05). Conclusions: Glenoid lateralization was consistently associated with increased acromial and scapular spine strain, whereas inferiorization of the glenosphere reduced strain in the biomechanical studies analysed in this systematic review. Humeral-sided lateralization may increase or decrease acromial or scapular spine strain. Independent of different design parameters, the transection of the coracoacromial ligament resulted in significantly increased strains and scapular spine strains were also increased when the acromion was more posteriorly oriented. The results found in this systematic review of biomechanical in-silico and in-vitro studies may help in the surgical planning of RTSA to mitigate complications associated with acromion and scapular spine fracture.

Reverse total shoulder arthroplasty (RTSA) is increasingly used for the treatment of complex proximal humerus fractures and fracture sequelae. In 2021, half a dozen models of fracture stems are commercially available, reflecting its growing utility for fracture management. Prosthesis designs, bone grafting and tuberosity fixation techniques have evolved to allow better and more reliable fixation of tuberosities and bony ingrowth. Patients with anatomical tuberosity healing not only have an increased range of active anterior elevation and external rotation, but also experience fewer complications and longer prosthesis survival. This review provides an overview of recent evidence on basic and fracture-specific RTSA design features as well as tuberosity fixation techniques that can influence tuberosity healing.

Introduction: Aging and effect of antiretroviral therapy on bone mass could increase the risk of femoral neck fractures (FNF) in HIV patient. The aim of this study was specifically to determine whether intracapsular FNF in HIV-positive patients are more prone to short-term post-operative complications than similar fractures occurring in HIV-negative patients. Materials and methods: A group of 25 HIV-positive patients with intracapsular FNF were enrolled and matched to HIV-negative patient with similar fractures according to gender, age, a modified Charlson Comorbidity Index (CCI), fracture classification, surgical treatment and time interval between fracture event and surgery. For each group, length of stay, surgical time, early clinical outcomes and short-term surgical and medical complications were compared to determine the impact on the early outcome. Results: At the time of the fracture occurrence, 56% of HIV-positive patients were on antiretroviral therapy and 12% started with therapy in the perioperative period. At three months follow-up, there were no statistically significant differences between the two study groups in length of stay, Harris hip score and total number of early complications. However, a statistically significant increase in urinary tract infections and longer surgical time using hip sliding screw fixation were seen in the HIV-positive group. The poorest post-operative result was seen in a patient who failed to adequately adhere to the HIV therapy protocol. Conclusions: This study failed to show any statistically significant increase in short-term complications or worse clinical outcomes for intracapsular FNF in HIV-positive patients compared to HIV-negative patients to recommend their treatment in dedicated centres.

PURPOSE:At the beginning of this century, unprecedented interest in the concept of using less invasive approaches for the treatment of knee degenerative diseases was ignited. Initial interest in this approach was about navigated and non-navigated knee reconstruction using small implants and conventional total knee arthroplasty.METHODS:To this end, a review of the published literature relating to less invasive compartmental arthroplasty of the knee using computer-based alignment techniques and on soft tissue-dedicated small implants is presented. The authors present and compare their personal results using these techniques with those reported in the current literature. These involved the use of a shorter incision and an emphasis sparing. However, nowadays most surgeons look at compartmental knee resurfacing with the use of small implants as the new customized approach for younger and higher-demand patients. The aim of this paper is to stimulate further debate.RESULTS:Since the beginning of 2000, computer-assisted surgery has been applied to total knee arthroplasty (TKA) and later to compartmental knee arthroplasty. Recent studies in the literature have reported better implant survivorship for younger patients using navigation in TKA at longer-term follow-up. Only one published report was identified showing superior clinical outcomes at short-term follow-up using computer-assisted technology compared with conventional alignment techniques in small implant surgery. No studies were found in the literature that demonstrated similar clinical advantages with navigated small implants at long-term follow-up. Two published meta-analyses were identified reporting better implant and limb alignment and no increase in complications using a navigated unicompartmental knee arthroplasty. However, neither meta-analysis showed superior clinical outcomes or survivorship with the navigated techniques.CONCLUSION:In conclusion, we can assert that replacing just the damaged compartment and preserving the normal biomechanics will require not only new implant designs but also new technologies allowing the surgeon to make extremely precise adjustments to implant alignment and providing continuous feedback during surgery.LEVEL OF EVIDENCE:IV.

Purpose The aim of this study is to present the clinical and radiological results of a cemented unicompartmental knee arthroplasty (UKA) using a flat all-polyethylene tibial component at long-term follow-up, in a homogeneous group of patients with medial femoro-tibial knee arthritis. Methods The study group included 53 knees in 51 patients who were treated between January 1998 and November 1999 using a flat all-polyethylene tibial component. The same surgical technique was used for all patients. Inclusion criteria included a diagnosis of atraumatic arthritis, pre-operative flexion greater than 100° with no flexion deformity, a varus deformity of less than 10°, and a body mass index (BMI) less than 35. A neutral mechanical axis was considered the end-point in all interventions. The patients were assessed clinically using the International Knee Society (IKS) and the functional scores at follow-up. Plain radiographs were used to determine the alignment of the mechanical axis at 5, 10 and 14.7-year follow-up. A radiographic analysis of loosening, based on the method described by the IKS, was performed and the degree of arthritic progression in the non-resurfaced compartment was also assessed. Results At latest follow-up five patients had died and the data for three patients had not been collected. At final review four knees had undergone revision surgery and a further patient had declined a recommended revision TKA. The main indication for revision surgery was progressive aseptic loosening of the tibial component in female patients. No revisions were required because of arthritic progression in the lateral compartment. Over time the clinical outcomes did not show statistically significant differences. There was a significant worsening of the mechanical axis at the last follow-up compared with the results at five and ten year review. Conclusions This study demonstrated that, in primary arthritis involving the medial femoro-tibial compartment, UKA using a flat all-polyethylene component could be considered an effective surgical option. Attention should be paid to progressive worsening of the mechanical axis over time associated with progressive radiolucency especially in female patients. Level of evidence IV

Despite good overall clinical results, unicompartmental knee replacements (UKR) are not without their problems and failures have been reported. The most common causes of UKR failure are component loosening, poor patient selection, poor surgical technique, polyethylene wear and progression of arthritis in other compartments. The purpose of this study is to present a series of atraumatic fractures of metallic components in a UKR treated in a single orthopaedic centre.

Background Conversion of a knee arthrodesis to a Total Knee Arthroplasty is an uncommon procedure. Revision Total Knee Arthroplasty in this setting presents the surgeon with a number of challenges including the management of the extensor mechanism and patella. Case presentation We describe a unique case of a 69 years old Caucasian man who underwent a revision Total Knee Arthroplasty using a tibial tubercle osteotomy after a previous conversion of a knee arthrodesis without patella resurfacing. Unfortunately 9 months following surgery a tibial tubercle pseudarthrosis and spontaneous patella fracture occurred. Both were managed with open reduction and internal fixation. At 30 months follow-up the tibial tubercle osteotomy had completely consolidated while the patella fracture was still evident but with no signs of further displacement. The patient was completely satisfied with the outcome and had a painless range of knee flexion between 0-95°. Conclusions We believe that patients undergoing this type of surgery require careful counseling regarding the risk of complications both during and after surgery despite strong evidence supporting improved functional outcomes.

The aim of this study was to retrospectively compare the results of two matched-paired groups of patients who had undergone a medial unicompartmental knee arthroplasty (UKA) performed using either a conventional or a non-image-guided navigation technique specifically designed for unicompartmental prosthesis implantation.Thirty-one patients with isolated medial-compartment knee arthritis who underwent an isolated navigated UKA were included in the study (group A) and matched with patients who had undergone a conventional medial UKA (group B). The same inclusion criteria were used for both groups. At a minimum of six months, all patients were clinically assessed using the Knee Society Score (KSS) and the Western Ontario and McMaster Osteoarthritis Index (WOMAC) index. Radiographically, the frontal-femoral-component angle, the frontal-tibial-component angle, the hip-knee-ankle angle and the sagittal orientation of components (slopes) were evaluated. Complications related to the implantation technique, length of hospital stay and surgical time were compared.At the latest follow-up, no statistically significant differences were seen in the KSS, function scores and WOMAC index between groups. Patients in group B had a statistically significant shorter mean surgical time. Tibial coronal and sagittal alignments were statistically better in the navigated group, with five cases of outliers in the conventional alignment technique group. Postoperative mechanical axis was statistically better aligned in the navigated group, with two cases of overcorrection from varus to valgus in group B. No differences in length of hospital stay or complications related to implantation technique were seen between groups.This study shows that a specifically designed UKA-dedicated navigation system results in better implant alignment in UKA surgery. Whether this improved alignment results in better clinical results in the long term has yet to be proven.

This study presents a consecutive series of patients who underwent total knee arthroplasty (TKA) after prior distal femoral fracture without hardware removal. The purpose of this study was to determine the effectiveness of computer-assisted TKA in patients with posttraumatic arthritis, specifically those with retained hardware after prior distal femoral fracture. The study group included a consecutive series of 16 patients who had developed posttraumatic knee arthritis after a distal femoral fracture with retention of hardware (group A). Patients in the study group were matched with patients who had undergone a computer-assisted TKA using the same implant and software (group B). The indication for TKA in all group B patients was atraumatic arthritis, and surgery was performed during the same period as that in the study group. Patients were matched for age, sex, preoperative range of motion, preoperative severity of arthritis, type and grade of deformity, and implant features. No statistically significant differences existed between the 2 study groups in terms of operative time, duration of hospital stay, or intra- and postoperative complications. At last follow-up, no statistically significant differences existed in Knee Society Scores and Western Ontario and McMaster Universities Arthritis Index scores. Implant alignment and radiological parameters were similar in both groups. This study demonstrated that posttraumatic knee arthritis after prior distal femoral fracture can be safely managed using a computer-assisted TKA without hardware removal. Comparison between the study group and a matched group with atraumatic arthritis showed similar postoperative results and complication rates.

Background: The Authors present the results of a series of navigated total knee replacements (TKR) without hardware removal in patients with post-traumatic arthritis following femoral fractures. The purpose of the paper was to determine the effectiveness of computer-assisted TKR in these patients compared to routine primary implants.Methods: Sixteen patients with post-traumatic knee arthritis following a distal femoral fracture and retained hardware were included in the study (group I). Patients in the study group were matched with patients who had undergone a computer navigated TKR using the same implant and software (group II). The indication for TKR in all group II patients was atraumatic arthritis and surgery was performed in the same period as the study group. Patients were matched for age, gender, pre-operative range of motion, severity of arthritis pre-operatively, type and grade of deformity and implant features.Results: There were no statistically significant differences in surgical time, hospital staying or intra-operative and post-operative complications between the two study groups. At the latest follow-up no statistically significant difference was seen for the Knee Society Score and WOMAC indices. Implant alignment and radiological parameters were similar in both groups.Conclusions: This study demonstrated that post-traumatic knee arthritis following prior distal femoral fracture can be safely managed using a computer navigated TKR without hardware removal. Comparison between this patient group and a matched group with atraumatic arthritis showed similar post-operative results and complication rates.Level of evidence: HI. (C) 2012 Elsevier B.V. All rights reserved.

Leg length discrepancy following total hip replacement (THR) can contribute to poor hip function. Abnormal gait, pain, neurological disturbance and patient dissatisfaction have all been described as a result of leg length inequality after THR. The purpose of this study was to determine whether the use of computer navigation in THR can improve limb length restoration and early clinical outcomes. We performed a matched-pair study comparing 48 computer-assisted THR with 48 THRs performed using a traditional freehand alignment method. The same implant with a straight non-modular femoral stem was used in all cases. The navigation system used allowed the surgeon to monitor both acetabular cup placement and all the phases of femoral stem implantation including rasping. Patients were matched for age, sex, arthritis level, pre-operative diagnosis and pre-operative leg length discrepancy. At a minimum follow-up of six months, limb length discrepancy was measured using digital radiographs and a standardised protocol. The number of patients with a residual discrepancy of 10 mm or more and/or a post-operative over-lengthening were measured. The clinical outcome was evaluated using both the Harris Hip Score and the normalised Western Ontario and McMaster Universities (WOMAC) Arthritis Index. Restoration of limb length was significantly better in the computer-assisted THR group. The number of patients with a residual limb length discrepancy greater than 10 mm and/or a post-operative over-lengthening was significantly lower. No significant difference in the Harris Hip Score or normalised WOMAC Arthritis Index was seen between the two groups. The surgical time was significantly longer in the computer-assisted THR group. No post-operative dislocations were seen.

Computer-assisted total knee replacement (TKR) has been shown to improve radiographic alignment. Continuous feedback from the navigation system allows accurate adjustment of the bone cuts, thus reducing errors. The aim of this study was to determine the impact of experience both with computer navigation and knee replacement surgery on the frequency of errors in intraoperative bone cuts and implant alignment. Three homogeneous patient groups undergoing computer assisted TKR were included in the study. Each group was treated by one of three surgeons with varying experience in computer-aided and knee replacement surgery. Surgeon A had extensive experience in knee replacement and computer-assisted surgery. Surgeon B was an experienced knee replacement surgeon. A general orthopaedic surgeon with limited knee replacement surgery experience performed all surgeries in group C. The cutting errors and the number of re-cuts were determined intraoperatively. The complications and mean surgical time were collected for each group. The postoperative frontal femoral component angle, frontal tibial component angle, hip–knee–ankle angle and component slopes were evaluated. The results showed that the number of cutting errors were lowest for TKR performed by the surgeon with experience in navigation. This difference was statistically significant when compared to the general orthopaedic surgeon. A statistically significant superior result was achieved in final mechanical axis alignment for the surgeon experienced in computer-guided surgery compared to the other two groups (179.3° compared to 178.9° and 178.1°). However, the total number of outliers was similar, with no statistically significant differences among the three surgeons. Experience with navigation significantly reduced the surgical time.

The Authors present a match-paired study between computer assisted and free-hand techniques using a short modular femoral stem in total hip arthroplasty (Metha, B.Braun Aesculap, Tuttelingen; Germany). They assessed surgical time, clinical outcome, dislocation rate, limb length and off-set in 44 patients with ideal indication for this more conservative implants. Despite both longer surgical time and similar early outcomes, the results demonstrated how computer assisted techniques permits an easier way to manage limb length discrepancy and off-set restoring. The Authors do believe navigated short modular stems as safe procedure towards a real less invasive surgery in hip arthroplasty Introduction: Tissue sparing joint replacement surgery has been a focus for many surgeons well before the recent enthusiasm for minimally invasive total hip replacement (THR) gripped the international orthopaedic community (1,2). However most of the attention given to this area has involved dedicated instruments to reduce the required surgical exposure (3). Likewise with a more frequent use in young and active patients bone saving procedures become more important and one of the goal is to save good bone stock for the revision procedure (4). Recently short stems preserving the femoral neck are available on the market to address these selected cases with first positive reports(5,6,7). Even more recently a new modular stem together with a navigation technology to support the selection of the right component and to optimize joint reconstruction has been proposed. Intraoperatively with the navigation the surgeon can evaluate limb length, medialization of the center of rotation and ROM (8,9) Discrepancy of leg is often considered as a significant problem after Total Hip Replacement and has been associated to patient dissatisfaction (10,11). Pain, instability, stiffness, nerve traction and heteretopic ossification are described as direct and indirect consequences of a leg length discrepancy as well as of an incorrect off-set (12). In literature different studies demonstrated substantial statistical improvement in accuracy of cup placement using navigation compared with freehand methods but very few studies regarding stem navigation are reported in literature and none evaluating the effect of navigation upon leg length discrepancy (13,14,15,16) . The Authors performed a matched paired study between 2 groups of modular short stem in hip arthroplasty: with (Ca-THR) o without the navigation support. They hypothesized that Ca-THR permits to achieve a better joint reconstruction with an effective control over the leg length discrepancy. Furthermore they compared the 2 groups according to hip function and number of post operative dislocations. Materials and Methods: Twentytwo patients who underwent to a Ca-THR using using a CT-free computer assisted alignment system (Orthopilot 3.1, Aesculap, Tuttelingen; Germany) from April 2006 to January 2008 were included in the study (group A). All patients had a body mass index lower than 35. Patients with a displastic hip, limb length discrepancy bigger than 2 cm and with femoral neck /head major deformity were not included in this study because not ideal candidates for this implant. Every single patients in group A was matched with a patient who had undergone to a conventional free-hand THR (group B) between April 2006 and January 2008 in our hospital. Criteria of matching were age (with a maximum difference of + 3 years), sex, arthritis level, preoperative diagnosis and pre-operative limb length discrepancy (with a maximum difference of + 0.3cm). All the involved limbs were shorter or equal to the opposite limbs. In both the group the same postero-lateral approach was used to implant the same prostheses (Metha modular short stem and Plasma-Cup, B.Braun Aesculap, Tuttelingen; Germany). Early weight bearing as tolerated was encouraged in all patients. The duration of surgery was documented in all cases. Pre and postoperatively both limb discrepancy and the off-set were assessed radiologically using the method of Woolson et al. (17) with IMPAX digital radiography software (Agfa-Gevaert, NV, USA). At the latest follow-up the off-set was calculated as the difference between the pre and post operative off-set values. All the radiographs were always taken with a standardized protocol with the same magnification. We have painstakingly educated and communicated with our radiographers to repeated if any mistake was detected. The radiographs were assessed by an independent radiologist blinded to the original procedure. Furthermore at a minimum follow-up of 3 months the clinical outcome was evaluated using the Harris Hip Score and any dislocation was registered. Statistical Analysis was carried out using SPSS for Windows Release 11.0 (SPSS Inc, Chicago, Ill, USA). Data were represented as a mean and standard deviation for continuous response variables and as percentages for discrete variables. Differences between the two groups were measured with an independent Student’s T test or MannWhitney non-parametric test depending on the data distribution of the continuous variables. Results: No statistical differences in patients demographic data were registered. The mean followup was 10.8 months and 11.6 months respectively for group A e group B with no statistical significant difference. There were no significant differences in pre-operative limb length discrepancy between the 2 groups (mean 0.9 cm and 1.1 cm respectively for group A and B) (Tab 1). In both the groups pre-operatively there were primary hyperthophic osteoarthritis in 18 patients, vascular necrosis in 3 patients and post-traumatic osteoarthritis in one (Tab 1). No intraoperative technical problem was registered in both the groups. In group A in 20 case a 32 mm ceramic head was used while a 28 mm ceramic head was used in 2 cases. In Group B a 32 mm head was used in 19 cases while a 28 mm ceramic head was used in 3 cases. In group A we registered a major variability in the femoral neck adapters (both in inclination and ante/retroversion) and neck size of the head (Fig1,2). The surgical time was statistically longer in group A with a mean of 102.6 minutes compared to 87.7 minutes in group B (Tab 2). At the latest follow-up no sign of major subsidence were present in all the implants. The mean discrepancy was statistically better reduced in the computer assisted group. In this group the mean post-operative discrepancy was reduced to 0.4 cm with no cases of discrepancy greater of 1 cm. In group B the mean post-operative discrepancy was reduced to 0.8 cm but with 2 (9 %) cases of discrepancy still greater of 1.0 cm. Postoperatively in both the groups no cases of leg discrepancy greater than 2cm was registered even if in 3 (13.6%) case in group B the discrepancy was increase of a mean values of 0.4 cm. The offset was better recreated in the computer assisted group compared to the freehand group with a statistical significant lower difference between the pre-op and post-op values (Tab 2). There were no statistically significant differences in the Harris Hip score and all the patients were satisfied with the outcome. In group A the mean HHS score was 90.1 and 89 in gruop B futhermore we realized that the final outcome was still improving considering the short follow-up in some cases (Tab 2). In the group B 1 patient experienced a traumatic dislocation because a car accident 7 months postoperatively with further 2 more recent atraumatic dislocations with no sign of implant loosening and he is scheduled for a THR revision. No cases of dislocation was registered in group A. Discussion: Short stem prostheses represent an attractive alternative to resurfacing hip arthroplasty in the same selected cases (4,6). In combination with minimal invasive techniques permits to preserve muscular structure and bone stock avoiding complications related to resurfacing implants (18). The neck is partially maintained and the greater trochanter region remains untouched as well as the methaphysis is not filled leaving spongious bone (4,6,8). Furthermore the newest implants associate short stem to modularity trying even to better restore the hip anatomy and biomechanics with no risks of mechanical failure( 8,9,19). Our main concern on this implants is the leg length discrepancy as well as in resufarcing implants. Lazovic in 2006 has already reported a significant percentage of elongation from 1 cm to 1.5 cm with the same implant even with a navigation support (9). Thus we do not use this implant routinately in “longer hips”. Likewise different studies has already demonstrated better implant placement using navigation in THR either for the cup insertion or for the stem (13,14,15,16). Navigation of short stem implants is mainly based on the restoration of the hip anatomy with no influence on the stem positioning (8,9). The navigation can evaluate intraoperatively the best modular neck and head size to achieve the planned off-set, leg-length and range of motion and even in our study in the navigated group we better exploited the different modular neck options. At a minimum follow-up of 3 months after the surgical intervention, we performed a matched paired study comparing 22 computer assisted THR to traditional free-hand THR using the same short modular stem. Our study has some limitations: it was retrospective and not randomised, with a too short follow-up to pick up any objective clinical difference between the 2 groups. Furthermore the series was too small even to demonstrate any reduction in the dislocation rate compared to the percentage reported in literature. However we tried to identify strict inclusion criteria (diagnosis, age and sex, body-mass index, shortening) to matched the best indications for this implant. We include patient with no elongation on the affected side and we tried to correct the discrepancy with this implant. No cases of primary atraumatic dislocation were regis

In total knee replacement (TKR), regarding tibial component positioning, almost all implants offer both an intramedullary and an extramedullary alignment guide, leaving it up to the surgeon which guide to use. However, early failure in TKR can be caused by incorrect positioning or orientation with poor limb alignment. Recently computer-based alignment systems have been developed to help the surgeon to overcome these complications. The Authors retrospectively analysed their experience using a computer-based CT-free alignment system. They assessed the radiological alignment of the tibial components in 38 computer-assisted TKR 6 months after surgery. The frontal tibial component angle (FTC) and the sagittal orientation of the tibial component (slope) were evaluated 6 months after the operation. The results were compared to those achieved with traditional alignment systems. The surgical time was statistically longer in the computer-assisted group but in this group all the tibial components were aligned within 4° of all the ideal measurements in both frontal and sagittal planes.

Recently computer-assisted joint replacement surgery has been introduced to improve implant alignment. To date no intra-operative fractures have been reported related to the insertion of the navigation trackers used in this technique. The authors present the case of a 76-year-old man who sustained an intra-operative tibial fracture at the site of insertion of the navigation tracker during computer assisted total knee replacement.

Recently mini-invasive joint replacement has become one of the hottest topics in the orthopaedic world. However, these terms have been improperly misunderstood as a “key-hole” surgery where traditional components are implanted with shorter surgical approaches, with few benefits and several possible dangers. Small implants as unicompartmental knee prostheses, patellofemoral prostheses and bi-unicompartmental knee prostheses might represent real less invasive procedures: Tissue sparing surgery, the Italian way to minimally invasive surgery (MIS). According to their experience the authors go through this real tissue sparing surgery not limited only to a small incision, but where the surgeons can respect the physiological joint biomechanics.

We present a match-paired study between computer-assisted and freehand techniques using a short modular femoral stem (Metha; B. Braun Aesculap, Tuttlingen, Germany) in total hip replacement (THR). Surgical time, clinical outcome, dislocation rate, limb length, and offset in 44 patients with ideal indication for this more conservative implant were assessed. Despite both longer surgical time and similar early outcomes, the results showed how computer-assisted techniques allow easier management of limb length discrepancy and offset restoring. We believe that navigated short modular stems are safe for less invasive THR.