Introduction

Radiological Inclination (RI) is defined as the angle formed between the acetabular axis and the longitudinal axis when projected onto the coronal plane. Higher RI angles are associated with adverse outcomes.

Background

The current orthopaedic literature demonstrates a clear relationship between acetabular component positioning, polyethylene wear and risk of dislocation following Total Hip Arthroplasty (THA). Problems with edge loading, stripe wear and squeaking are also associated with higher acetabular inclination angles, particularly in hard-on-hard bearing implants.

The important parameters of acetabular component positioning are depth, height, version and inclination. Acetabular component depth, height and version can be controlled with intra-operative reference to the transverse acetabular ligament.

Control of acetabular component inclination, particularly in the lateral decubitus position, is more difficult and remains a challenge for the Orthopaedic Surgeon. Lewinnek et al described a ‘safe zone’ of acetabular component orientation: Radiological acetabular inclination of 40 ± 10° and radiological anteversion of 15 ± 10°.

Accurate implantation of the acetabular component within the ‘safe zone’ of radiological inclination is dependent on operative inclination, operative version and pelvic position.

Traditionally during surgery, the acetabular component has been inserted with an operative inclination of 45°. This assumes that patient positioning is correct and does not take into account the impact of operative anteversion or patient malpositioning.

However, precise patient positioning in order to orientate acetabular components using this method cannot always be relied upon. Hill et al demonstrated a mean 6.9° difference between photographically simulated radiological inclination and the post-operative radiological inclination. The most likely explanation was felt to be adduction of the uppermost hemipelvis in the lateral decubitus position. The study changed the practice of the senior author, with target operative inclination now 35° rather than 40° as before, aiming to achieve a post-operative radiological inclination of 42° ± 5°.

Sagittal stability of the knee is believed to be of significant importance following total knee arthroplasty. We examine four different knee designs at a minimum of twenty-four months postoperatively. Sagittal stability was measured at four degrees of flexion: 0°; 30°; 60°; and 90°, to examine the effect of design on mid-flexion stability.

The knee designs included were: the rotating platform LCS design (DePuy); the cruciate sparing Triathlon system (Stryker); SAIPH system (Matortho, UK); and the medial rotating knee design, MRK (Matortho, UK).

Following ethical approval, 64 cases were enrolled into the study, 22 male and 42 female. Inclusion criteria included: a minimum of 18 months from surgery; ability to flex beyond 90 degrees; and have no postoperative complications. 18 LCS, 18 MRK, 14 SAIPH and 14 Triathlon knee designs were analysed. Sagittal stability was measured using the KT1000 device. Active range of movement was measured using a hand held goniometer and recorded as was Oxford knee score, WOMAC knee score, SF12 and Kujala patellofemoral knee score.

Mean follow-up was 33.7 months postoperative, with a mean age of 72 years. Mean weight was 82.7kgs and height 164cms. There was no significant difference in preoperative demographics between the groups. Mean active post-operative range of motion of the knee was from 2–113° with no significant difference between groups.

Sagittal stability was similar in all four groups in full extension; however the MRK and SAIPH designs showed improved stability in the mid-range of flexion (30–90°). Patient satisfaction also showed a similar trend with MRK achieving better patient reported functional outcomes and satisfaction than that of the SAIPH, LCS and Triathlon systems.

All four knee designs demonstrated good post-operative range of movement with comparative improvement of patient scores to other reported studies. The MRK and SAIPH knee design showed an improved mid-flexion sagittal stability with better patient reported satisfaction and functional scores.

Ideal placement of the acetabular component remains elusive both in terms of defining and achieving a target. Our aim is to help restore original anatomy by using the transverse acetabular ligament (TAL) to control the height, depth and version of the component. In the normal hip the TAL and labrum extend beyond the equator of the femoral head and therefore, if the definitive acetabular component is positioned such that it is cradled by and just deep to the plane of the TAL and labrum and is no more than 4mm larger than the original femoral head, the centre of the hip should be restored. If the face of the component is positioned parallel to the TAL and psoas groove the patient specific version should be restored. We still use the TAL for controlling version in the dysplastic hip because we believe that the TAL and labrum compensate for any underlying bony abnormality.

The TAL should not be used as an aid to inclination. Worldwide, > 75% of surgeons operate with the patient in the lateral decubitus position and we have shown that errors in post-operative radiographic inclination (RI) of > 50° are generally caused by errors in patient positioning. Consequently, great care needs to be taken when positioning the patient. We also recommend 35° of apparent operative inclination (AOI) during surgery, as opposed to the traditional 45°.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):37–43.

Introduction

Operative inclination (OI) is defined as the angle between the acetabular axis and the sagittal plane. With the patient in the true lateral decubitus position, this corresponds to the angle formed between the handle of the acetabular component inserter and the theatre floor intra-operatively.

Sagittal stability of the knee is believed to be of significant importance following a total knee arthroplasty. We examine three different knee designs at a minimum of twenty-four months postoperatively. Sagittal stability was measured at four degrees of flexion; 0°, 30°, 60° and 90° to examine the effect of design on mid-flexion stability.

The knee designs included the rotating platform LCS design, the cruciate sparing Triathlon system and the medial rotating knee design, MRK.

Following ethical approval 50 cases were enrolled into the study, 15 male and 35 female. Eighteen LCS, 18 MRK and 14 Triathlon knee designs were analysed. Sagittal stability was measured using the KT1000 device. Active range of movement was measured using a hand held goniometer and recorded as was Oxford knee score, WOMAC knee score, SF12 and Kujala patellofemoral knee score.

Mean follow-up was 37 months postoperative with a mean age of 73 years. Mean weight was 82.7 kgs and height 164 cms. There was no significant difference in preoperative demographics between the groups. Mean active post-operative range of motion of the knee was from 2–113° with no significant difference between groups.

Sagittal stability was similar in all three groups in full extension; however the MRK design showed improved stability in the mid-range of flexion (30–90°). Patient satisfaction also showed a similar trend with MRK achieving slightly better patient reported outcomes than that of the LCS and Triathlon systems, although this was not statistically significant.

All three knee designs demonstrated good post-operative range of movement with comparative improvement of patient scores to other reported studies. The MRK knee design showed an improved mid-flexion sagittal stability.

Introduction

Modularity is being increasingly used throughout the world for both primary and revision total hip arthroplasty. Recently there have been concerns of increased corrosion and fretting at the modular junctions. In the SROM® modular hip system, two modular junctions are the head-neck taper junction and the stem-sleeve taper junction. The aim of this study was to investigate corrosion at these junctions with the use of different bearing materials.

Aim: To develop a flexion jig that would reliably hold the post-op knee in fixed flexion for a defined time period and determine its influence on peri-operative blood loss, transfusion, pain, and complications (specifically nerve palsy)following TKA.

Methods/Results: A previous study in this department showed immediate postoperative flexion to significantly reduce blood loss following TKR. Following this study, time in flexion was increased to 12 hours in an attempt to further reduce blood loss., some patients then developed a painful lower limb nerve palsy. This palsy was caused by pressure from the jig in the popliteal fossa/calf on nerves. The design of the jig was altered to remove pressure from these areas. Because of this design change, we were unsure whether the new jig would have the same blood saving effect, necessitating a new study.

This prospective randomised controlled trial recruited 420 patients into 3 equal groups: extension, 3 & 6 hrs flexion.

This trial found a significant reduction in blood loss(12%, p=0.006) and length of stay(1/2 day, p=0.006) in the 6 hour flexion group, compared the extension group.

There was no significant difference in pain or complication rates (excluding nerve palsy).

2 patients in the 6 hour group had postoperative nerve palsy, however, this palsy was sensory only and markedly different to that found previously. Although the palsy rate in this study is similar(1.4%) to quoted literature rates (1.3%) for TKA, it is difficult to know if the jig was the cause of palsy as the there was a difference between those caused by the old metal jig (painful) and those in this study (sensory loss only).

Conclusion: The results of this study show post-op flexion for 6 hours to significantly reduce perioperative blood loss. Palsy was reduced to match rates as quoted in the literature.

Introduction: A critical determinant of early dislocation following total hip arthroplasty (THA) is correct positioning of the acetabular component. This challenging aspect of THA has not been lessened by the introduction of more minimally invasive techniques. In this paper we introduce a simple and reproducible technique, which uses the transverse acetabular ligament (TAL) to determine cup orientation. We have used this technique as the sole method of cup orientation in our last 1000 consecutive primary total hips.

Methods: One thousand consecutive patients were studied in order to determine the prevalence of early dislocation (within 3 months) following acetabular component placement determined by reference to the transverse ace-tabular ligament. All patients underwent primary total hip arthroplasty via a posterolateral approach with a posterior repair.

Results: At a minimum follow-up of 9 months (range 9–39 months) 6 of the 1000 hips (0.6%) had dislocated.

Conclusion: Although multiple factors are known to contribute to this rate correct placement of the acetabular component is critical. As our results compare favourably with other published series where a posterior repair has been performed by extrapolation we feel that that the TAL does provide an acceptable method of determining cup orientation. The fact that it is independent of patient position on the table and is easy to locate with a minimally invasive approach makes it an attractive method.

Ensuring the accuracy of the intra-operative orientation of the acetabular component during a total hip replacement can be difficult. In this paper we introduce a reproducible technique using the transverse acetabular ligament to determine the anteversion of the acetabular component. We have found that this ligament can be identified in virtually every hip undergoing primary surgery. We describe an intra-operative grading system for the appearance of the ligament. This technique has been used in 1000 consecutive cases. During a minimum follow-up of eight months the dislocation rate was 0.6%. This confirms our hypothesis that the transverse acetabular ligament can be used to determine the position of the acetabular component. The method has been used in both conventional and minimally-invasive approaches.

Objective: To examine the impact of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) on preoperative haemoglobin levels and perioperative transfusion rates in patients undergoing total knee arthroplasty (TKA).

Methods: We examined the pre-operative haemoglobin (Hb) and haematocrit (Hct) of a consecutive series of 81 patients, looking at the relationship between the pre-operative use of Aspirin/NSAIDs on preoperative Hb, postoperative Hb deficit and the perioperative transfusion rate. A single surgeon performed all procedures using an LCS TKR (Depuy, Leeds UK). A standardised transfusion protocol was used.

Results: The patients were grouped according to their pre-operative use of aspirin or a NSAID, singly or in combination. The patient groups are as shown in the table below. All groups were comparable for age, BMI and ASA grade.

Results show a significantly higher transfusion rate (p=0.048) in the group of patients who received a combination of aspirin and a NSAID compared to the other groups. The patients on aspirin or a NSAID alone also had an increased transfusion rate but the increase was not statistically significant (p=0.12 and p=0.07 respectively).

Conclusion: The use of both aspirin and an NSAID in combination leads to a lower preoperative Hb and an increased post-operative transfusion requirement following total knee arthroplasty.

Current methods for restoring or preserving limb length following total hip arthroplasty are anatomically inaccurate, as they do not consider acetabular and femoral height independently. In order to address this, we present and evaluate a technique that uses the transverse acetabular ligament to control the vertical height of the acetabular component and a caliper that controls the vertical placement of the femoral component within the femoral canal. Limb lengths were measured in 200 patients who had undergone primary total hip arthroplasty using this technique. Using this method, 94% had a post-operative limb length inequality that was 6 mm or less when compared to the normal side (average +0.38 mm). The maximum measured limb length inequality was ± 8 mm.

Isolated patellofemoral osteoarthritis has been reported to occur in approximately 5% of patients with gon-arthrosis of the knee. A number of options are available for the surgical management of these individuals. We reported the short-term outcomes on thirty three patients (33 knees) with isolated patellofemoral osteoarthritis who underwent LCS total knee arthroplasty (TKA) without resurfacing who had been operated on between 1996 – 1999¹.

Barrack et al² in 2001 reported on the incidence of anterior knee pain in two groups of TKA patients, one with patella resurfacing and one without. They reported an increase incidence of anterior knee pain in both groups.

We now report the longer-term outcomes with an average follow-up of 80.2months (range 54–94 months). At latest review, 9 patients experienced night time pain, all describing it as improved from their preoperative level. Twelve patients walked with the use of a walking aid, compared with 21 preoperatively. Disease specific scores at latest review showed improved outcome measures at latest review.

We also report our outcomes in an additional fifty-five patients (59 knees) with isolated patellofemoral osteoarthritis who were treated between 1999–2004 receiving an LCS total knee arthroplasty without patellar resurfacing. Our preliminary findings suggest that this technique continues to be an option in the management of the older patient with isolated patellofemoral osteoarthritis.

Purpose: The objective of this study was to examine the relationship between aspirin and other non-steroidal anti-inflammatory drugs (NSAIDS) on postoperative blood loss following Total Knee Arthroplasty

Methods: We prospectively examined the pre-operative consumption of aspirin and NSAIDS and haematological parameters of 50 consecutive patients undergoing Total Knee Arthroplasty. 22 (44%) patients were on aspirin only, 17 (34%) patients on aspirin and another NSAID and 11 (22%) patients were taking neither aspirin nor a NSAID. (All patients received 150mg of aspirin the evening before surgery as DVT prophylaxis).

Results: The average pre-operative haemoglobin of the group taking aspirin and a NSAID, aspirin only and neither aspirin nor NSAID group was 12.9g/dl, 13,8g/dl and 13.49g/dl respectively. The drop between their pre-operative level and Day 3 Haemoglobin level was 3.788g/dl, 4.45g/dl and 4.28g/dl respectively.

The same trend was reflected in the PCV drops of 0.111, 0.133 and 0.1273 respectively. Transfusion rates for the three groups showed that those on aspirin and another NSAID had the highest rate with an average of 0.235 units per patient compared to 0.136 for those on aspirin only and 0.10 for those on neither aspirin nor NSAID.

Discussion: These findings indicate that the ingestion of aspirin or a NSAID preoperatively does not increase the amount of blood loss following total knee arthroplasty (TKA). The higher transfusion rates in the aspirin and NSAID group is because of the lower preoperative haemoglobin as compared to the other groups studied.

Conclusion: Observation of transfusion trends within our unit has shown a transfusion rate of 18% in patients with a preoperative Haemoglobin level of greater than 13.0g/dl as compared to 48% with a haemoglobin level of 13.0g/dl or less (review of 180 consecutive patients undergoing Total Knee Arthroplasty).

The ingestion of aspirin and NSAID does not increase blood loss following TKA but significantly have a lower preoperative Hb level. We feel that pre-operative Haemoglobin levels are the best predictors of transfusion requirements following total knee arthroplasty.

Introduction: Hip fractures affects more than 65,000 people in the UK each year and this number is increasing. The standard treatment is insertion of either a dynamic hip screw or hemiarthroplasty depending on fracture configuration. Because of their advanced age, associated co-morbid factors as well as having had an implant inserted, hip fracture patients are at increased risk of developing post-operative wound infections. The infection rate for hip fracture surgery is quoted at 0.6 – 3.6%¹.

Methods: We carried out a retrospective study of the readmission rate due to wound infection following treatment of their fractured neck of femur. 20 patients (16 females and 4 males) were identified over a 24 month period out of a total 1786 femoral neck fractures treated (1.1%).

Results: 11 patients re-admitted with a wound infection had had a hemiarthroplasty fixation, 9 following insertion of a DHS. 7 patients (0.4%) had a superficial wound infection (3 hemi, 4 DHS) and 13 (0.7%) a deep wound infection (8 hemi, 5 DHS). Treatment for the superficial wound infections included 6 patients requiring IV antibiotics and 1 requiring washout and resuturing of the wound.

Treatment of deep wound infections included 6 who had a Girdlestone procedure, 2 had wound washout, debridement and 2 who had removal of DHS. All received IV antibiotics. 2 patients were deemed unfit for surgery and received IV antibiotics only.

3 patients with a deep wound infection (23%) died (2 deemed unfit for surgery, and 1 Girdlestone) during their admission. 85% of the readmissions had an ASA score of three or over. We looked at the length of operation time and found that 15 took less than 45 minutes, 4 took between 45 and 60 minutes and one took over 60 minutes. Three of the operations which took over 45 minutes developed deep infections.

Conclusion: Fractured neck of femur accounts for a large proportion of fracture admissions. Accepted methods of treatment carry significant infection rates. Superficial wound infections can in the majority be treated with IV antibiotics. Deep wound infections carry a significant mortality rate. Operating time should be within 45 minutes where possible to reduce the risk of deep infection. Post-operative wound infections are associated with an ASA grade of 3 or greater.

Purpose: The objective of this study was to observe the change in transfusion rate by decreasing the transfusion trigger for patients undergoing primary total knee arthroplasty.

There are no transfusion guidelines defined for Total knee arthroplasty (TKA), and each orthopaedic unit usually has its own protocol when it comes to transfusion. With the present climate of concern about non-autologous blood transfusions and transmission of infection, orthopaedic units are trying to keep their transfusion rates to a minimum and only transfuse when absolutely necessary.

Method: The transfusion trigger prior to protocol change was a haematocrit (Hct) < 0.31, which was then changed to a lesser trigger of Hct < 0.25. We collected data on 331 patients; 181 patients prior to the change and 150 patients after the change. Each patient had undergone a primary TKA by a single surgeon using the same operative technique.

Results: In the group prior to change in transfusion trigger (Hct < 0.31), 76% of patients were transfused 88% of females and 54% of males. In this pre-trigger change group, 100% of patients with a pre-operative Hb of 12g/dl or less were transfused.

Of the 150 patients reviewed after the change in transfusion trigger (Hct < 0.25), only 29% were transfused – 35% of females and 18% of males. 50% of patients with a pre-operative Hb of 12 g/dl or less were transfused.

Conclusion: A change in the transfusion trigger greatly reduced the transfusion rate (reduction of 45%) with no adverse patient events. Obviously, this has both clinical and financial benefits. Pre-operative Hb is the best indicator as to whether a patient will require a transfusion following TKA. In order to decrease transfusion rates further, patients with a pre-operative Hb < 12 g/dl may benefit from pre-operative boosting of their Hb.