Aims: Limb length discrepancy is a recognised complication of total hip arthroplasty (THA). Cementless THAs are increasingly being used, but in order to achieve rotational and axial stability larger implants may be required than originally templated for. This could potentially result in greater limb length discrepancy. Our objective was to determine if limb length discrepancy exists to a greater degree in cementless THA. Methods: 166 consecutive patients undergoing elective THA between June 2007 and May 2008 were included in this retrospective study. Post-operative, digital radiographs (PACS, Centricity. ®. ) were examined for each of these patients to determine limb length. Limb length discrepancy was calculated as the difference between the perpendicular distance between the inter-teardrop line and the most prominent points on the lesser trochanter of each limb. Magnification was determined from the measured radiographic diameter of the prosthetic heads and their actual diameters. Results: Of the 166 patients included in this study 128 had cementless THA and 38 had cemented. The average magnification was calculated as 30%. Limb length discrepancy was found post-operatively in 93% of cases. In 65% of patients the operated limb was longer (by 0 – 29 mm) and in 28% it was shorter (by 0 – 23 mm). The mean limb length discrepancy, corrected for magnification, was 6.21 mm for cemented THA and 6.22 mm for cementless THA. A student’s T-test demonstrated no significant difference in limb length discrepancy between these operations (p = 0.996). Conclusions: The incidence of limb length discrepancy after THA is high. However, no significant differences were demonstrated between cemented and cementless THAs in our series. Accurate and careful pre-operative templating is important in THA to minimise the risk of clinically significant limb length discrepancy

Background. Limb length discrepancy after total hip replacement is one of the possible complications of suboptimal positioning of the implant and cause of patients dissatisfaction. Computer assisted navigation become affirmed in last years for total hip replacement surgery and it is also used for the evaluation of the intra-operative limb length discrepancy. The purpose of this study is to verify the reliability of a navigation system with a dedicated software in intraoperative evaluation of limb lengthening and offset as compared with manual technique. Methods. Forty patients who underwent a Total Hip Arthroplasty in our institution were entrolled in this study. Twenty patients were evaluated with pre operative manual planning (group A) and treated with hand positioning of femoral stem. Twenty Patient were evaluated with preoperative manual planning and treated with Computer assisted navigation of Stem (group B). Mean operating time and blood loss were analyzed. Radiological and clinical follow up was made at 1, 3, 6 and 12 months postoperative to assess any mismatch of implant, complications and clinical results that was measured with Harris Hip Score. Results. In the evaluation of the limb length and offset in group A there wasn't significance difference between pre and postoperative measurements obtained with manual planning. Also in group B there wasn't a significance difference between the measurement obtained intraoperative with computer assisted navigation and the one obtainedafter surgery and preoperative with manual planning. In any case we noted a limb length discrepancy in this series. No statistically significance difference was noted between the two groups in relations to the others parameters investigated. Conclusions. Based on our study the computer navigation system is a simple and reliable for the evaluation of limb length discrepancy and offset in total hip replacement. This Navigation system can offer to the surgeon a valid intraoperative information that can reduce possible errors in stem positioning and can reduce rate of length discrepancy

We evaluated 100 patients in two separate groups of 50 patients for Limb Length Discrepancy after Charnley Total Hip Arthroplasty. The study was a retrospective analysis of the group considered. Group 1 included 50 consecutive patients with unilateral disease who underwent total hip arthroplasty between June 98 – June 99 without intraoperative measurement. Group II included 50 patients with unilateral disease who underwent total hip arthroplasty between June 98 – July 99 with pre-operative templating and intraoperative measurements. Evaluation was undertaken with radiographs using the method of Williamson and Reckling. Two independent observers evaluated pre-operative radiographs and postoperative radiographs taken at a mean of 3 months (6 weeks – 6 months). The inter-oberserver variation was found in 9 preoperative radiographs and 15 postoperative radiographs in the 100 patients (p< 0.6). The mean age of the patients in Group I was 71 years and 4 months (52–83 years) with 24 males and 26 females. The mean age of patients in group II was 69 years and 7 months (41–82 years) with 25 males and 25 females. 23 patients (46%) in group I had a discrepancy of which 19 patients (38%) had a mean increase of o.4cm (0.1–0.8cm) and 4 patients (8%) had a mean decrease in length of 0.325cm (0.2–1.1cm). In group II 14 patients (28%) had a discrepancy with 9 patients (18%) had an mean increase of 0.41cm(0.1–1cm) and a mean decrease of 0.3cm(0.1–0.6cm). The discrepancy found in our series of 100 patients in minimal. The discrepancy can be minimised to a further extend with pre operative templating and intraoperative measurements (p< 0.04). Our study supports the adoption of this to prevent limb length discrepancy after total hip arthroplasty

A number of series report limb length discrepancy in long bone chronic osteomyelitis, however in most cases, it is shortening of the affected bone. This is thought to be due to damage in the affected growth plate leading to early growth arrest. However, it is known that the inflammatory state of chronic osteomyelitis results in an increased blood supply and, as in other conditions such as rheumatoid arthritis, the increased blood supply results in overgrowth of the affected bone. In order to study the effect of long bone chronic osteomyelitis on limb length, we designed a prospective trial of 42 consecutive patients presenting to our unit with chronic osteomyelitis of a long bone. The inclusion criteria were all patients presenting with a long bone osteomyelitis. There were no exclusion criteria. The mean age at presentation was 10.3 years. The mean duration of symptoms of 18.2 months prior to presentation. For 37 (88%) of patients the cause of osteomyelitis was haematogenous. On examination, 3 (7%) patients had shortening of the long bone compared to the unaffected side (of an average of 2.5cm), whilst 13 (31%) patients had overgrowth of the affected bone (average overgrowth 2.2cm). The most common bone affected was the tibia (20/42, 48%), followed by the femur (8/42, 19%) and the humerus (6/42, 14%). All patients underwent radiographic analysis, and the average percentage of long bone affected was 59%. 8/42 (12%) of patients had at least one physis affected (2 of these patients had undergrowth and 1 had overgrowth). This large prospective series of patients is the first in the world literature to show the effect of osteomyelitis on the growth of long bones, in particular an overgrowth rate of 31%. We suggest that the mechanism for this is related to the duration of symptoms. In areas of the world where there is poor access to health care, there is consequently a prolonged period of increased blood supply as a result of inflammation. This increased blood supply may make limb length discrepancy is more likely to be due to overgrowth rather than undergrowth

Purpose: We retrospectively reviewed the pre- and postoperative radiographs of 116 patients receiving primary THA in a high volume arthroplasty centre to evaluate technical causes for limb length discrepancy. We hypothesized that limb lengthening most commonly occurs as a result of low placement of the acetabular implant. Method: A sample of 116 primary THA’s performed between 2005 and 2007 with complete one-year postoperative clinical outcomes scores and appropriate radiographs available on PACS were identified from a prospective arthroplasty database. Pre- and one-year postoperative AP bilateral hip radiographs were reviewed, and pre- and post-operative leg length discrepancy as well as the respective acetabular and femoral contribution to any postoperative leg length discrepancy (if present) were measured. Results: We found that 19 THA’s out of 116 (16.4%) were lengthened greater than 8 mm. Mean difference from preoperative to postoperative leg length was 13.3 mm (SD 7.6 mm). A mean of 6.3 mm (SD 6.2 mm) in lengthening was contributed by the femoral stem, and 5.3 mm (SD 6.3 mm) of lengthening was contributed by placement of the acetabular implant (p=0.738). There was a significant correlation between lengthening of the limb and femoral placement of the stem (r=0.5, p< 0.0001). Likewise, there was a strong correlation between limb lengthening and low placement of the cup (r=0.6, p< 0.0001). Of those limbs that were lengthened greater than 8 mm, Oxford Hip Score at one-year post-operative was not correlated with over-lengthening (r=0.06, p=0.551). Conclusion: These results support our hypothesis that limb lengthening is indeed due to low placement of the acetabular implant, and equally this was attributable to error in placement of the femoral stem. We conclude that with careful preoperative planning and intraoperative identification of the tear drop, a significant reduction in clinically relevant limb lengthening can be achieved

Purpose of study: Long bone chronic osteomyelitis may result in limb length discrepancy by shortening of the affected bone when the physis is damaged. Little is known about the rates of overgrowth of infected long bones. This study documents the relative rates of overgrowth and undergrowth in a large series of chronic osteomyelitis patients. Methods: Forty-two consecutive patients presenting to our unit with chronic osteomyelitis of a long bone were included. There were no exclusion criteria. The mean age at presentation was 10.3 years. The mean duration of symptoms was 18.2 months prior to presentation. For 37 (88%) of patients the cause of osteomyelitis was haematogenous. Results: Three (7%) patients had shortening of the long bone compared to the unaffected side (average 2.5cm), whilst 13 (31%) patients had overgrowth of the affected bone (average overgrowth 2.2cm). The tibia was most commonly affected (20/42, 48%), followed by the femur (8/42, 19%) and the humerus (6/42, 14%). The average proportion of long bone involved on X-ray was 59%. At least one physis was affected in 8/42 (12%) patients (2 had undergrowth, 1 overgrowth). Conclusions: This large prospective series of patients shows the effect of osteomyelitis on the growth of long bones, in particular an overgrowth rate of 31%. The mechanism for this is probably related to the duration of symptoms. In areas of the world with poor access to health care, there is consequently a prolonged period of increased blood supply as a result of inflammation. This increased blood supply may make overgrowth limb length discrepancy more likely than undergrowth

Limb length discrepancy (LLD) is a complication of total hip arthroplasty (THR). We reviewed the x-rays of patients who underwent THR in our unit to establish the incidence and magnitude of LLD, and try to identify reasons why a length discrepancy arose. Patients with abnormalities of the opposite hip (previous THR, significant osteoarthritis) were excluded, to allow comparison with a normal contralateral side. 100 consecutive patients who fulfilled these criteria were included. There were 38 male and 62 female patients. The implants used were Charnley (89 cases), Elite (4 cases), and Exeter (7 cases). The following measurements were made on pre-and post-operative films on the hospital PACS system: centre of lesser trochanter to ischial tuberosity; tip of greater trochanter to centre of femoral head; centre of head to base of teardrop. The distance from the osteotomy in the femoral neck to the centre of the lesser trochanter was also measured. The interval from the greater trochanter to the closest margin of the pelvis, and the interval from the lesser trochanter to the base of the teardrop (compared to the normal side) were recorded as indices on adduction. Surgery was performed via a direct lateral (Hardinge) approach (95 cases) or through transtrochanteric approach (5 cases). There was a radiographic difference between limbs of > 1cm in 43 cases; in 9 of these, the operated limb was longer, and in 34 cases it was shortened. In those cases where the operated side was lengthened, the cause was on the acetabular side in 2 patients, and on the femoral side in 25 cases, and on the femoral side in 9 cases. The shortened limb was noted to be adducted relative to the opposite side in 29 patients. There was difference noted in the incidence of discrepancy between different implants. The transtrochanteric approach was associated with significantly (p< 0.01) less length discrepancy. Our findings suggest that shortening is much more common than lengthening following THR, and that incorrect positioning of the acetabulum is the more likely cause. Persistence of an adduction contracture may also contribute to an apparent shortening postoperatively. The transtrochanteric approach appeared to make LLD less likely. Surgeons should be aware of these findings when performing THR. The clinical effect of differing degrees of LLD is till debatable

Patients with hemiplegic cerebral palsy walk with a well recognised characteristic gait pattern. They also commonly have a significant leg length discrepancy which is less well appreciated. The typical equinus gait in these patients is assumed to be an integral part of the disease process of spasticity and a tendency to develop joint contractures. However an alternative explanation for the presence of an equinus deformity may be that it is a response to the development of a significant leg length discrepancy in these patients. The development of such an equinus deformity would have the effect of functionally lengthening the short hemiplegic leg. We set up a study to examine the correlation between leg length discrepancy and equinus deformity. We reviewed the gait analyses and clinical examinations of 183 patients with hemiplegic cerebral palsy. While 22% had no significant leg length discrepancy, 65% had a measured discrepancy of greater than 1cm. There was a linear correlation between age and limb length discrepancy. We also found that there was a linear relationship between leg length discrepancy and ankle equinus at the point of ground contact. We propose that the equinus deformity seen in the hemiplegic cerebral palsy patient is multifactorial and is related not only to the disease state but also to the presence of leg length discrepancy. The equinus deformity functionally lengthens the short hemiplegic leg. Indeed it may represent an attempt by these patients to functionally equalise their leg lengths. This factor must be taken into account when considering correction of an equinus deformity in patients with hemiplegic cerebral palsy in order to avoid either recurrence of the deformity or the production of functionally unequal leg lengths. We have also highlighted the presence of significant shortening of the hemiplegic leg in these patients

The aims of this study were to compare the outcome of epiphysiodesis in patients with limb length discrepancy (LLD) as a result of cerebral palsy with those as a result of other causes in order to test our hypothesis that the hemiplegic / monoplegic limb may respond differently to epiphysiodesis, to evaluate the accuracy of the Moseley method and evaluate whether there is any difference between the outcomes of left or right hemiplegic limbs with LLD bearing in mind that the left hand is used for bone age calculations. We reviewed the case notes and radiographs of 34 children who had undergone epiphysiodesis for the management of LLD by the same surgeon, using the Moseley method between February 1999 and May 2005 to final follow up at skeletal maturity. Of the 34 patients, 9 had a LLD as a result of cerebral palsy (4-Left, 5-Right) and 25 as a result of other causes. In the cerebral palsy group the mean residual LLD was 0.59cm and in the other group it was 1.18cm. Both groups were similar in terms of age and sex distribution. There was no demonstrable statistically significant difference in outcome between the 2 groups (unpaired T test, P=0.734). The Moseley method appeared accurate and there was no difference demonstrated in the outcome between left and right hemiplegic LLD. We conclude that the Moseley method is reliable. We have not found any evidence that the hemiplegic limb behaves any differently. We have not demonstrated any difference in the outcome of left or right hemiplegic limbs

Purpose

Leg length discrepancy after total hip arthroplasty (THA) sometimes causes significant patient dissatisfaction. In consideration of the leg length after THA, leg length discrepancy is often measured using anteroposterior (AP) pelvic radiography. However, some cases have discrepancies in femoral and tibial lengths, and we believe that in some cases, true leg length differences should be taken into consideration in total leg length measurement. We report the lengths of the lower limb, femur, and tibia measured using the preoperative standing AP full-leg radiographs of the patients who underwent THA.

Abstract

Introduction

To minimize leg length discrepancies (LLD), preoperative measures are taken using the PACS; the head center to the proximal end of the lesser trochanter distance (HLD) of the opposite side of the operating limb are calculated, while during operation, the modular neck selection is adapted to equal the opposing limb's length.

The purpose of this study was to see whether the HLD method would show far less occurrences of LLD, in comparison to the conventional method(preoperative templating and shuck test).

Leg length discrepancy (LLD) following total hip arthroplasty (THA) is a well-known and documented phenomenon. LLD can pose a substantial problem for both the patient and the surgeon. Patient dissatisfaction with LLD after THA is the most common reason for litigation against orthopaedic surgeons. Failure to restore limb length may lead to an unstable hip, whereas over-lengthening may cause low back pain, sciatic nerve palsy and early mechanical loosening.

Several intra operative techniques both invasive and non invasive have been reported in the literature to over-come LLD during THA. The accuracy of all the methods that measure from pins anchored into pelvis to point on the greater trochanter may be affected by the inherent variability of the leg position when measurements are made. Bending or dislodging the pins and using of calliper devices can be cumbersome during the THA surgery and can compromise the measurements.

Hence we describe a simple, safe and reliable intra operative technique to overcome LLD by using a stout braided suture material tied to the stout Judd pin used to retract the soft tissues in posterior approach. Utilising the routine incision for the posterior approach to the hip, this technique can be easily carried out in primary THA surgery as compared to other techniques used to avoid LLD, which require further incision, and specialised equipment which are time consuming, cumbersome and may not be very secure. This technique of using a suture mark over the Judd pin is simple, inexpensive and easily adaptable.

Leg length discrepancy (LLD) can adversely affect functional outcome and patient satisfaction after total hip arthroplasty. We describe a novel intraoperative technique for femoral component insertion.

We aimed to determine if this technique resulted in the desired femoral placement, as templated, and if this was associated with a reduced LLD.

A series of fifty consecutive primary total hip replacements were studied. Preoperative digital templating was performed on standardised PA radiographs of the hips by the senior surgeon. The preoperative LLD was calculated and the distance from the superior tip of the greater trochanter to the predicted shoulder of the stem was calculated (GT-S). Intraoperatively, this length was marked on the rasp handle and the stem inserted to the predetermined level by the surgeon. This level corresponded to the tip of the greater trochanter and formed a continuous line to the mark on the rasp handle. Three independent blinded observers measured the GT-S on the postoperative radiographs. We assessed the relationship between the senior author's GT-S (preoperative) and the observers' GT-S (postoperative) using a Person correlation. The observers also measured the preoperative and postoperative LLD, and the inter-observer variability was calculated as the intra-class correlation coefficient.

There was a strong correlation of preoperative and postoperative GT-S (R=0.87), suggesting that the stem was inserted as planned. The mean preoperative and postoperative LLD were −4.3 mm (−21.4–4) and −0.9 mm (−9.8–8.6), respectively (p<0.001).

This technique consistently minimised LLD in this series. This technique is quick, non-invasive and does not require supplementary equipment.

Aims. Congenital pseudarthrosis of the tibia (CPT) has traditionally been a difficult condition to treat, with high complication rates, including nonunion, refractures, malalignment, and leg length discrepancy. Surgical approaches to treatment of CPT include intramedullary rodding, external fixation, combined intramedullary rodding and external fixation, vascularized fibular graft, and most recently cross-union. The current study aims to compare the outcomes and complication rates of cross-union versus other surgical approaches as an index surgery for the management of CPT. Our hypothesis was that a good index surgery for CPT achieves union and minimizes complications such as refractures and limb length discrepancy. Methods. A multicentre study was conducted involving two institutions in Singapore and China. All patients with CPT who were surgically managed between January 2009 and December 2021 were included. The patients were divided based on their index surgery. Group 1 included patients who underwent excision of hamartoma, cross-union of the tibia and fibula, autogenic iliac bone grafting, and internal fixation for their index surgery. Group 2 included patients who underwent all other surgical procedures for their index surgery, including excision of hamartoma, intramedullary rodding, and/or external fixation, without cross-union of the tibia and fibula. Comparisons of the rates of union, refracture, limb length discrepancy, reoperations, and other complications were performed between the two groups. Results. A total of 36 patients were included in the study. Group 1 comprised 13 patients, while Group 2 comprised 23 patients. The mean age at index surgery was four years (1 to 13). The mean duration of follow-up was 4.85 years (1.75 to 14). All patients in Group 1 achieved bony union at a mean of three months (1.5 to 4), but ten of 23 patients in Group 2 had nonunion of the pseudarthrosis (p = 0.006). None of the patients in Group 1 had a refracture, while seven of 13 patients who achieved bony union in Group 2 suffered a refracture (p = 0.005). None of the patients in Group 1 had a limb length discrepancy of more than 2 cm, while ten of 23 patients in Group 2 have a limb length discrepancy of more than 2 cm (p = 0.006). In Group 1, four of 13 patients had a complication, while 16 of 23 patients in Group 2 had a complication (p = 0.004). Excluding removal of implants, four of 13 patients in Group 1 had to undergo additional surgery, while 18 of 23 patients in Group 2 had to undergo additional surgery following the index surgery (p = 0.011). Conclusion. A good index surgery of excision of hamartoma, cross-union of the tibia and fibula, autogenic iliac bone grafting, and internal fixation for CPT achieves union and minimizes complications such as refractures, limb length discrepancy, and need for additional surgeries

Aims. Adult patients with history of childhood infection pose a surgical challenge for total hip arthroplasty (THA) due to distorted bony anatomy, soft-tissue contractures, risk of reinfection, and relatively younger age. Therefore, the purpose of the present study was to determine clinical outcome, reinfection rate, and complications in patients with septic sequelae after THA. Methods. A retrospective analysis was conducted of 91 cementless THAs (57 male and 34 female) performed between 2008 and 2017 in patients who had history of hip infection during childhood. Clinical outcome was measured using Harris Hip Score (HHS) and Modified Merle d’Aubigne and Postel (MAP) score, and quality of life (QOL) using 12-Item Short Form Health Survey Questionnaire (SF-12) components: Physical Component Score (PCS) and Mental Component Score (MCS); limb length discrepancy (LLD) and radiological assessment of the prosthesis was performed at the latest follow-up. Reinfection and revision surgery after THA for any reason was documented. Results. There was significant improvement in HHS, Modified Merle d’Aubigne Postel hip score, and QOL index SF 12-PCS and MCS (p < 0.001) and there was no case of reinfection reported during the follow-up. The minimum follow-up for the study was three years with a mean of 6.5 (SD 2.3; 3 to 12). LLD decreased from a mean of 3.3 cm (SD 1) to 0.9 cm (SD 0.8) during follow-up. One patient required revision surgery for femoral component loosening. Kaplan-Meier survival analysis estimated revision-free survivorship of 100% at the end of five years and 96.9% (95% confidence interval 79.8 to 99.6) at the end of ten years. Conclusion. We found that cementless THA results in good to excellent functional outcomes in patients with a prior history of childhood infection. There is an exceedingly low rate of risk of reinfection in these patients, even though complications are not uncommon. Cite this article: Bone Jt Open 2022;3(4):314–320

Introduction. Fully implantable systems are used commonly only after maturity. What are indications to use fully implantable systems at the femur even in children?. Materials and Methods. Implantable lengthening nails (FITBONE) were used retrograde at the femur in minimal invasive technique to correct a limb length discrepancy of >6 cm. In 5 cases a relevant deformity was corrected in the same surgery. In all cases a final step of lengthening was planned at the femur and at the tibia with fully implantable devices at maturity. Results. 18 patients with the medium age of 10,3 years (8–14) were treated. In 17 cases the goal of lengthening was achieved without any complication. In one case of proximal femoral deficiency lengthening had to be stopped because of increasing tendency of knee joint luxation. Bone formation occurred circular around the nail in all cases. Full load bearing was possible in the average after 2,2 days/mm. No technical problems occur. In one case induced deformity in the lateral plane was observed which was corrected at the final step. At the end of treatment functional and cosmetical result was perfect in all cases. Conclusions. Fully implantable motorized distraction nails are a favorable option for lengthening and deformity correction of the femur even for children older than 10 years to correct limb length discrepancy of more than 6 cm. The treatment has a low pain level, is comfortable and nearly no scars are visible

Background The magnitude of the medial offset and the limb length discrepancy after a total hip replacement (THR) significantly alters the biomechanics of the hip. If both these components are not properly restored, the rate of dislocation may increase. Further decreased offset may result in impingement at the extremes of movement, and also results in soft-tissue laxity, while increased offset increases stress within the stem that may lead to stem fracture or loosening. In addition to affecting the clinical outcome, limb length discrepancy may also cause legal problems. Aim To find out whether intraoperative assessment and restoration of desired offset, and correction of limb length discrepancy actually corrects these two components as assessed by postoperative radiographs. Material and Methods We evaluated 39 consecutive THRs in 37 patients who had the surgery performed via the posterior approach. Intraoperatively the medial offset was measured using a ruler from the tubercle in the trochanteric fossa to the centre of rotation of the head, and then check again after the seating of the femoral prosthesis. The size of the head was then accordingly altered. The limb length was measured using the ruler parallel from the lesser trochanter, and taking it upto the tip of the greater trochanter. The preoperative and the postoperative radiographs were evaluated for the medial offset and limb length discrepancy. The medial offset was calculated as a ratio in reference to the opposite side. Results The median medial offset was 93.9 (85–100) preoperatively and 94.2 (85–110) postoperatively. The median limb length discrepancy was improved from a preoperative −4.84mm (0 to −30mm) to a postoperative −0.06mm (−9 to +16mm). Discussion Preoperative templating may be a way of obtaining the correct medial offset and limb length in THRs. However, varus or valgus placement, and sinking or protrusion of the prosthesis may alter both these components significantly. Hence, intraoperative measurement and thus changing the components and the position of the stem accordingly may be the best method in addition to preoperative templating, in achieving the required offset and minimising limb length discrepancy in THRs

INTRODUCTION. Leg length discrepancy following total hip arthroplasty (THA) can be functionally disabling for affected patients and can lead on to litigation issues. Assessment of limb length discrepancy during THA using traditional methods has been shown to produce inconsistent results. The aim of our study was to compare the accuracy of navigated vs. non navigated techniques in limb length restoration in THA. METHODS. A dataset of 160 consecutive THAs performed by a single surgeon was included. 103 were performed with computer navigation and 57 were non navigated. We calculated limb length discrepancy from pre and post op radiographs. We retrieved the intra-operative computer generated limb length alteration data pertaining to the navigated group. We used independent sample t test and descriptive statistics to analyse the data. RESULTS. The two subgroups were matched for age, diagnosis and preoperative leg length discrepancy. The mean age was 69.12 (37–89, SD-8.3) and the mean BMI was 29 (19–44, SD-5.03). The mean post op limb length discrepancy in the non navigated group was 5 mm (SD-6) as compared to mean of 3.5mm (SD-6.5) for the computer navigated group. This difference was statistically significant (p<0.04). 18% of patients in the non navigated group had a limb length discrepancy of >10 mm as compared to 12% in the navigated group. There was no statistically significant difference between the computer predicted leg length alterations and those measured on radiographs. (p>0.15). DISCUSSION & CONCLUSION. The use of Computer navigation in THA can be useful in reducing errors related to leg length discrepancy. It helps in reducing the rates of unacceptably high discrepancies. In our experience, the results of this technique were predictable and reproducible. We intend to continue using this tool for our total hip arthroplasties

Knee arthrodesis is a potencial salvage procedure for limb preservation in patients with multiple failures of Total Knee Arthroplasty (TKA) with massive bone loss and extensor mechanism deficiency. The purpose of the study is to evaluate the outcome of bridging knee arthrodesis using a modular and non cemented intramedullary nail in patients with septic failure Total Knee Arthroplasty. Between 2005 and 2013 (9 years), 15 patients (13 female and 2 male) with mean age 71.1 years (range 41 to 85) were treated at our Institution with septic two- stage knee arthrodesis using a modular and non- cemented intramedullary nail after multiple failures of septic Total Knee Arthroplasty. Mean follow- up was 70.1 months (24 to 108 months) with a minimum follow- up of 24 months. We evaluated the erradication of infection clinically and with normalization of laboratory parameters (ESR and CRP), limb length discrepancies and complications (periimplant fractures, amputation rates, wound healing disturbances) and the subjective evaluation of the patients after knee arthrodesis. We reported 11 cases of resolution of the infection (73.3 %), with good tolerance of the implant and a mean limb length discrepancies of 15 mm. Of these, 8 patients had been monitored over 5 years without recurrence of the infection. The mean number of previous operations was 4.9 (range 2 to 9). Two patients (13.3 %) required multiples surgical debridements for uncontrolled sepsis and finally underwent knee amputation. Coagulase- negative Staphylococci (SCN) were the most commom pathogen (53.3 %) followed by polimicrobian infections (26.7 %). One patient continues suppressive antibiotic treatment and 1 patient was treated with a one- stage custom- made arthrodesis nail exchange. Bridging knee arthrodesis using a modular and non- cemented intramedullary nail is a salvage procedure with acceptable results in terms of erradication of infection after septic faliure Total Knee Arthroplasty with restoration of limb length discrepancy. Despite these satisfactory results it is not without serious complications such as knee amputation