Abstract

Medial patellofemoral ligament (MPFL) reconstruction is an effective procedure to address patellofemoral instability, however there remains no clear consensus on the optimum technique. Variations in patella tunnel and the use of patella fixation devices are reported in the literature, as are the associated complications of patella fracture and hardware irritation. We present the early results using a two tunnel, Endobutton free technique.

24 MPFL reconstructions (14 female, 10 male) were performed by a single surgeon, using two 3.5mm medial patellar tunnels exiting anteriorly and a looped, extra-synovial hamstring autograft. Femoral fixation was achieved using an non-absorbable interference screw. Mean age was 25.5 years, with a mean follow-up of 21.7 months. Mean Kujala scores were 60.8 preoperatively and 87.9 postoperatively (p<0.0001). No patient experienced further dislocation or patella fracture post-operatively. One patient required interference screw removal.

The surgical technique presented has outcomes comparable with the literature. It requires a shorter tendon graft, and removes the need for a patellar fixation device, reducing potential irritation and cost.

In September 2011 our departmental protocol for peri-operative prophylactic antibiotic administration was altered from cefuroxime to gentamicin/flucloxacillin, in response to reported links between cephalosporin use and Clostridium difficile (C. diff) infection.

As both gentamicin and flucloxacillin are known to be nephrotoxic in some patients, we investigated whether the new regimen increases the risk of Acute Kidney Injury (AKI) in patients undergoing elective and trauma hip and knee surgery, classified by severity (AKI Network criteria). The incidence of C. diff was noted.

10 out of 202 (5%) patients receiving cefuroxime (group A) developed AKI, compared with 23 of 210 (11%) patients receiving gentamicin and flucloxacillin (group B) (p=0.012). The severity of the renal injury was higher in the group B patients with 16 sustaining stage II/III AKI, whereas in Group A only one patient sustained a stage II injury and none stage III.

The increased AKI rate in group B was observed equally in hip fracture patients and elective hip/knee replacement patients. However, 3 of 80 (4%) patients with hip fractures who received doses of cefuroxime developed C. diff, with none in the other groups (p=0.04).

The choice of prophylactic antibiotics depends on a careful assessment of benefits and risks. Our data suggests that whereas hip fracture patients may have benefitted from the protocol change with reduced C. diff incidence, elective hip and knee replacement patients sustained additional harm. Different antibiotic regimens may be appropriate for these two groups.

The introduction of direct thrombin inhibitors in arthroplasty surgery has reignited the debate on the risk of wound complications when using chemical thromboprophylaxis. It has been suggested that direct thrombin inhibitors might lead to an increased risk of systemic and operative site bleeding and wound sepsis when compared to low molecular weight heparin.

In July 2009, departmental thromboprophylaxis policy for patients undergoing hip and knee replacement surgery (including revision) was changed from subcutaneous enoxaparin for the duration of inpatient stay to dabigatran for 10 days (knees) or 28 days (hips) unless contraindicated. In the 2 years prior to policy change, 1091 patients underwent hip or knee arthroplasty (Group A), with1150 patients undergoing the same procedures in the 2 years following July 2009 (Group B). A minority of patients were already on warfarin (2% in group 1, 3% in group 2).

This study presents a retrospective analysis of all patients who returned to theatre within 30 days of joint replacement surgery to assess whether the change in unit policy caused any discernible increase in bleeding-related complications.

In group A, 20/1091 patients (1.8%) returned to theatre within 30 days. 9 were for reasons unrelated to thromboprophylaxis (mainly dislocated hips), 4 for gastrointestinal bleeding and 7 for wound complications (haematoma, wound breakdown, or infection).

In group B, 22/1150 patients (1.9%) returned to theatre within 30 days. 13 were for unrelated reasons, 4 for gastrointestinal bleeding, and 5 for wound complications. One patient with a wound complication was on warfarin and therefore did not receive dabigatran.

The lower wound complication rate in group B was not statistically different.

This study, in a large heterogeneous group of patients, suggests that a change from enoxaparin to dabigatran does not increase the incidence of local or systemic complications of sufficient severity to warrant return to theatre.

The introduction of direct thrombin inhibitors in arthroplasty surgery has reignited the debate on the risk of wound complications when using chemical thromboprophylaxis. It has been suggested that direct thrombin inhibitors might lead to an increased risk of systemic and operative site bleeding and wound sepsis when compared to low molecular weight heparin.

In July 2009, departmental thromboprophylaxis policy for patients undergoing hip and knee replacement surgery (including revision) was changed from subcutaneous enoxaparin for the duration of inpatient stay to dabigatran for 10 days (knees) or 28 days (hips) unless contraindidated. In the 2 years prior to policy change, 1091 patients underwent hip or knee arthroplasty (Group 1), with1150 patients undergoing the same procedures in the 2 years following July 2009 (Group 2). A minority of patients were already on warfarin (2% in group 1, 3% in group 2).

This study presents a retrospective analysis of all patients who returned to theatre within 30 days of joint replacement surgery to assess whether the change in unit policy caused any discernible increase in bleeding-related complications.

In group 1, 23/1091 patients (2.1%) returned to theatre within 30 days. 8 were for reasons unrelated to thromboprophylaxis (mainly dislocated hips), 5 for gastrointestinal bleeding (mainly upper GI endoscopy) and 10 for wound complications (haematoma, wound breakdown, or washout of early infection). In group 2, 22 / 1150 patients (1.9%) returned to theatre within 30 days. 12 were for unrelated reasons, 5 for GI bleeding, and 5 for wound complications. The lower return to theatre rate in the second group was not statistically different.

This study, in a large heterogeneous group of patients, suggests that a change from enoxaparin to dabigatran does not increase the incidence of early infection, or the risk of bleeding at the operative site or the gastrointestinal tract.

Objectives

Our aim was to assess the use of intra-operative fluoroscopy in the assessment of the position of the tibial tunnel during reconstruction of the anterior cruciate ligament (ACL).

The outcome following arthroscopic anterior cruciate (ACL) reconstruction is dependant on a combination of surgical and non-surgical factors. Technical error is the commonest cause for graft failure, with poor tunnel placement accounting for over 80% of those errors.

A routine audit of femoral and tibial tunnel positions following single bundle hamstring arthroscopic ACL reconstruction identified apparent inconsistent positioning of the tibial tunnel in the sagittal plane. Intra-operative fluoroscopy was therefore introduced (when available) to verify tibial guide wire position prior to tunnel reaming. This paper reports a comparison of tibial interference screw position measured on post-operative radiographs with known tunnel position as shown on intra-operative fluoroscopic images in 20 patients undergoing routine primary ACL reconstruction between January and June 2009.

Surgery took a mean of 5 minutes longer when intra-operative fluoroscopy was used. In 3/20 patients, fluoroscopy led to re-positioning of the tibial guide wire prior to tunnel reaming. The mean tibial tunnel position as indicated by the tunnel reamer was 41 +/− 2.7 % of the total plateau depth (range 37% to 47%). The mean position projected from the tibial screw on post operative radiographs was 46 +/− 9.2% (range 38% to 76%). A paired t-test showed a significant difference (p = 0.022) between true tunnel position and tibial screw position. 6/20 patients had post operative screw positions that were > 5% more posterior than the known position of the tibial tunnel.

The position of the tunnel should be measured at its mid-point where this is evident. On most early radiographic images, the margins of the tunnel are not clear and therefore a line projected from the centre of the screw is used. This audit demonstrates the potential inaccuracy associated with this.

Resection of pulmonary metastases has previously been reported to improve outcome in high grade osteosarcoma (OS) patients with pulmonary metastases. In this study factors influencing survival in OS patients with pulmonary metastases were determined.

One hundred ninety seven patients with OS treated at our institution between 1990 and 2008 under the age of 40 were included. Excluded were patients with insufficient follow-up data (n=12) and irresectable primary tumour (n=11). Of the 174 remaining patients, 26 patients had pulmonary metastases at diagnosis and 62 developed pulmonary metastases during follow-up. Twenty-two of 88 patients (25%) also had extra-pulmonary metastases. Almost all patients with primary non-metastatic OS who experienced a relapse within 310 days (first tertile) died of disease, whereas patients with a relapse free interval of more than 310 days (second and third tertiles) have a significantly better overall survival at about 20% (p=0.02).

In total, 56 (63.6%) of 88 patients with pulmonary metastases were treated by metastasectomy. The main reason not to perform metastasectomy was irresect-ability by number and site. Patients with irresectable pulmonary metastases had higher numbers of pulmonary nodules (mean of six vs. three nodules) and more frequent bilateral involvement than patients eligible for surgery (p-values respectively 0.002 and 0.06). Independent risk factors determining survival after metastasectomy in multivariate analysis were male sex (p=0.05), higher numbers of pulmonary nodules (p=0.03) and necrotic metastases (p=0.04). Patients undergoing repeated metastasectomies had a similar chance of survival as patients who underwent metastasectomy once.

This well-defined cohort of patients with extensive follow-up data enabled us to identify important risk factors determining survival in OS patients with pulmonary metastases. Risk factors determining poor survival after pulmonary metastasectomy were male sex, higher numbers of pulmonary nodules and resection of vital metastases. Furthermore, we demonstrate that even after repeated metastasectomies, curation can be achieved.

Introduction: Patello-femoral instability (PFI) and pain may be caused by anatomical abnormality. Many radiographic measurements have been used to describe the shape and position of the patella and femoral trochlea. Some are difficult to apply when dysplasia is present.

This paper describes a simple new MRI measurement of the axial patellar tendon angle (APTA), and compares this angle in patients with and without patello-femoral instability.

Method: Axial MRI images of the knee of 20 patients with PFI and 20 normal knees (isolated acute ACL rupture) were used for measurement. The angle between the patellar tendon and the posterior femoral condylar line was assessed at three levels from the proximal tendon to its insertion.

Results: In normal knees, the APTA is 11 degrees of lateral tilt at all levels from the proximal tendon to its distal insertion. In PFI knees, the APTA is 32 degrees at the proximal tendon, 27 degrees at the joint line and 22 degrees at the distal insertion. The difference is significant (p< 0.001) at all levels.

Discussion: Measurement of the APTA is reproducible and is easier than many other indices of patello-femoral anatomy. In PFI, the APTA is increased by 21 degrees at the proximal tendon and by 11 degrees at its distal insertion.

In PFI, the patella is commonly tilted laterally. This is matched by the orientation of the patellar tendon. The increased tilt of the tendon is only partially corrected at its distal insertion with an abnormal angle of tibial attachment. When performing distal realignment procedures, angular correction as well as displacement may be appropriate.

Introduction: The medial tibial plateau is composed of two relatively flat facets. An anterior upward sloping “extension facet” (EF) articulates with the medial femoral condyle from 0 to 20–the stance phase of gait (in Man but not in other mammals). Anatomical variation in this area might be responsible for antero-medial osteoarthritis (AMOA).

This paper reports the angle between the EF and the horizontal (the extension facet angle- EFA) in normal knees and in knees with early AMOA.

Method: MRI reports were searched to identify patients with acute rupture of the ACL on the assumption that they had anatomically normal tibiae (46 males and 18 females) and patients with MRI evidence of early AMOA without bone loss (11 males and 9 females).

A sagittal image at the midpoint of the femoral condyle was used to determine the EFA.

Results: The EFA in normal tibiae is 14 +/− 5 (range 3–25). The angle is unrelated to age. The EFA in individuals with early AMOA is 19 +/− 4 (range 13–26). The difference is significant (p< 0.001).

Discussion: There is a wide variation in the EFA in normal knees which is unrelated to age.

There is an association between an increased EFA (ie a steeper EF) and MRI evidence of AMOA. Although a causal link is not proven, we speculate that a steeper angle increases the duration of loading on the EF in stance and tibio-femoral interface shear. This may initiate cartilage breakdown.

Introduction: Fresh autogenous cancellous bone graft is the material of choice in reconstruction and fusion procedures in foot and ankle surgery. There are many potential donor sites for graft harvest, all with recognised minor and major complications. The proximal tibia is one such potential site, and is particularly suited to foot and ankle surgery being within the operative field and under tourniquet control.

Purpose: To assess pain, morbidity and ability to weight bear in a large group of patients undergoing foot and ankle surgery utilising cancellous bone graft from the proximal tibia.

Method: A retrospective audit was undertaken of 148 procedures performed over a period of five years. Minimum follow-up was 3 months. Data were obtained from operation notes and patient interview.

Results: Most patients had no pain (78%) or very mild pain (20%) at the site of graft harvest immediately following surgery. At review, 96% had no pain; 4% had very mild pain with certain activities such as kneeling. There were no major complications. 4 patients (2.7%) had persisting areas of parasthaesia at review, but none were troubled by it. One patient had a superficial wound problem that resolved. The ability to bear weight was dictated by the primary procedure. Usually this was from 2–3 weeks. There were no complications related to early weight bearing in this series.

Conclusion: The proximal tibia is a suitable and safe site for bone graft harvest for foot and ankle surgery. There is no need for additional restriction in weight bearing following this procedure.

Introduction: Patello-femoral instability (PFI) and pain may be caused by anatomical abnormality. Many radiographic measurements have been used to describe the shape and position of the patella and femoral trochlea.

This paper describes a simple new MRI measurement of the axial patellar tendon angle (APTA), and compares this angle in patients with and without patello-femoral instability.

Method: Axial MRI images of the knee of 20 patients with PFI and 20 normal knees (isolated acute ACL rupture) were used for measurement. The angle between the patellar tendon and the posterior femoral condylar line was assessed at three levels from the proximal tendon to its insertion.

Results: In normal knees, the APTA is 11 degrees of lateral tilt at all levels from the proximal tendon to its distal insertion. In PFI knees, the APTA is 33 degrees at the proximal tendon, 28 degrees at the joint line and 22 degrees at the distal insertion. The difference is significant (p< 0.001) at all levels.

Discussion: Measurement of the APTA is reproducible and is easier than many other indices of patello-femoral anatomy. In PFI, the APTA is increased by 21 degrees at the proximal tendon and by 11 degrees at its distal insertion.

In PFI, the patella is commonly tilted laterally. This is matched by the orientation of the patellar tendon. The increased tilt of the tendon is only partially normalized at its distal insertion with an abnormal angle of tibial attachment. When performing distal realignment procedures, angular correction as well as displacement may be appropriate.

Introduction: Inadequate cementation of the acetabular component in hip replacement surgery leads to early aseptic loosening, the most common cause of revision. The optimum method of cementation has not been fully evaluated. This study aimed to determine the effect of the acetabular component flange on mean and peak pressure during component insertion.

Method: A 53mm deepened hemisphere was machined from aluminium. Pressure transducers were positioned at the rim, at 45 degrees, and at the base. Polyethelene acetabular components of different sizes and flange designs were mounted onto a materials testing machine and inserted at a constant rate into Palacos R cement within the aluminium hemisphere. Insertion was stopped at a pre-determined point when an even cement mantle was achieved. The same components were then tested without a flange. Each test was repeated six times. Output data from the transducers was analysed.

Results: Components with a flange create a mean pressure 6–18 times higher at the rim than those without a flange. At the base pressures are 2–4 times higher. A stiffer flange generates higher peak and mean pressures than a more malleable flange. Delaying insertion by one minute does not increase the pressures achieved unless a flange is used.

Discussion: These results strongly support the use of a flange to contain cement during insertion of the acetabular component. Unflanged components fail to achieve satisfactory mean or peak pressures, even if insertion is delayed. This is likely to result in poor cement penetration into bone and reduced longevity of interface fixation.

Introduction: The medial tibial plateau is composed of two relatively flat facets. An anterior upward sloping “extension facet” (EF) articulates with the medial femoral condyle from 0 to 20° – the stance phase of gait (in Man but not in other mammals). A horizontal “flexion facet” contacts the femur from 20° to full flexion. Anatomical variation in this area might be responsible for the initiation of antero-medial osteoarthritis (AMOA).

This paper reports the angle between the EF and the horizontal (the extension facet angle - EFA) in normal knees and in knees with early AMOA.

Method: MRI reports were searched to identify patients with acute rupture of the ACL on the assumption that they had anatomically normal tibiae (46 males and 18 females) and patients with MRI evidence of early AMOA without bone loss (11 males and 9 females).

A sagittal image at the midpoint of the femoral condyle was used to determine the EFA. Repeat measurements were taken by two observers.

Results: The EFA in normal tibiae is 14 +/− 5° (range 3 – 25°). The angle is unrelated to age. The EFA in individuals with early AMOA is 19 +/− 4° (range 13 – 26°). The difference is highly significant (p< 0.001).

Discussion: There is a wide variation in the EFA in normal knees that is unrelated to age.

There is an association between an increased EFA (ie a steeper EF) and MRI evidence of AMOA. Although a causal link is not proven, we speculate that a steeper angle increases the duration of loading on the EF in stance and tibio-femoral interface shear. This may initiate cartilage breakdown.

Patello-femoral instability (PFI) and pain may be caused by anatomical abnormality. Many radiographic measurements have been used to describe the shape and position of the patella and femoral trochlea.

This paper describes a simple new MRI measurement of the axial patellar tendon angle (APTA), and compares this angle in patients with and without patello-femoral instability.

Method: Axial MRI images of the knee of 20 patients with PFI and 20 normal knees (isolated acute ACL rupture) were used for measurement. The angle between the patellar tendon and the posterior femoral condylar line was assessed at three levels from the proximal tendon to its insertion.

Results: In normal knees, the APTA is 11 degrees of lateral tilt at all levels from the proximal tendon to its distal insertion. In PFI knees, the APTA is 33 degrees at the proximal tendon, 28 degrees at the joint line and 22 degrees at the distal insertion. The difference is significant (p< 0.001) at all levels.

Discussion: Measurement of the APTA is reproducible and is easier than many other indices of patello-femoral anatomy. In PFI, the APTA is increased by 21 degrees at the proximal tendon and by 11 degrees at its distal insertion.

In PFI, the patella is commonly tilted laterally. This is matched by the orientation of the patellar tendon. The increased tilt of the tendon is only partially normalized at its distal insertion with an abnormal angle of tibial attachment. When performing distal realignment procedures, angular correction as well as displacement may be appropriate.

Cemented, polished, tapered stems have produced excellent results, but some early failures occur in younger patients. The CPS-Plus stem (Plus Orthopedics AG, Switzerland) is a polished double taper with rectangular cross section for improved rotational stability. A unique proximal stem centraliser increases cement pressurisation, assists alignment and creates an even cement mantle.

Radiostereometric analysis has demonstrated linear subsidence in a vertical plane, without any rotation or tilt. These features should improve implant durability. Midterm (5 years) results of a prospective international multicentre study are presented.

Materials and Methods: 222 patients (230 hips) were recruited to this IRB-approved study at three centres in the UK and two in Norway. Clinical and radiographic outcomes were assessed at regular intervals.

Results: 160 hips in 153 patients were available for full clinical and radiographic evaluation. 27 patients have died, 30 patients were unable to attend (outcome known) and 12 patients have not reached 5 years follow-up.

The mean Harris hip score improved from 42 preoperatively to 91. There have been no revisions for aseptic loosening and none of the stems have radiographic evidence of loosening. There has been one revision for deep sepsis. With revision for aseptic loosening as an endpoint, stem survivorship is 100%.

Conclusion: The design of the CPS-Plus stem attempts to address the issues of cement pressurization, rotational stability, and subsidence. Earlier laboratory studies have now been supplemented by this clinical evaluation, performed in a number of different centres by several surgeons, and the midterm results are very encouraging.

From a search of MRI reports on knees, 20 patients were identified with evidence of early anteromedial osteoarthritis without any erosion of bone and a control group of patients had an acute rupture of the anterior cruciate ligament. The angle formed between the extension and flexion facets of the tibia, which is known as the extension facet angle, was measured on a sagittal image at the middle of the medial femoral condyle.

The mean extension facet angle in the control group was 14° (3° to 25°) and was unrelated to age (Spearman’s rank coefficient, p = 0.30, r = 0.13). The mean extension facet angle in individuals with MRI evidence of early anteromedial osteoarthritis was 19° (13° to 26°, SD 4°). This difference was significant (Mann-Whitney U test, p < 0.001).

A wide variation in the extension facet angle was found in the normal control knees and an association between an increased extension facet angle and MRI evidence of early anteromedial osteoarthritis. Although a causal link has not been demonstrated, we postulate that a steeper extension facet angle might increase the duration of loading on the extension facet during the stance phase of gait, and that this might initiate failure of the articular cartilage.

We retrospectively analysed the MR scans of 25 patients with patellofemoral dysplasia and ten control subjects, to assess whether there was any change in the morphology of the patella along its vertical length. Ratios were calculated comparing the size of the cartilaginous and subchondral osseous surfaces of the lateral and medial facets. We also classified the morphology using the scoring systems of Baumgartl and Wiberg. There were 18 females and seven males with a mean age of 20.2 years (10 to 29) with dysplasia and two females and eight males with a mean age of 20.4 years (10 to 29) in the control group.

In the patient group there was a significant difference in morphology from proximal to distal for the cartilaginous (Analysis of variance (ANOVA) p = 0.004) and subchondral osseous surfaces (ANOVA, p = 0.002). In the control group there was no significant difference for either the cartilaginous (ANOVA, p = 0.391) or the subchondral osseous surface (ANOVA, p = 0.526).

Our study has shown that in the dysplastic patellofemoral articulation the medial facet of the patella becomes smaller in relation to the lateral facet from proximal to distal. MRI is needed to define clearly the cartilaginous and osseous morphology of the patella before surgery is considered for patients with patellofemoral dysplasia.

Background Prescriptive guidelines for selection of implants for hip arthroplasty are likely to become increasingly established, on grounds of safety, cost and effectiveness. Such guidelines were introduced in the UK by the National Institute of Clinical Excellence (NICE) in 2000. Most departments were non-compliant in one or more respects, and knowledge of the recommendations was limited among clinicians. Concern exists that the recommendations may replace the Bolam Test in cases of clinical negligence in future.

Materials and Methods The recommendations of NICE, from the initial documentation to the present, were scrutinised alongside experience of other nationally-funded or managed healthcare systems in Europe and North America. The evolution of guidance from 1999 onwards, together with the areas of potential difficulty were identified.

Results Potential difficulties were encountered in relation to a number of implants in widespread use in the UK, particularly in relation to the choice of acetabular component (cup), despite the fact that cup loosening accounts for a third of revisions. The use of cup and stem from different manufacturers was also identified as a cause of concern.

Discussion Departments face a choice of adopting the recommendations of NICE in their entirety or continuing with established practice, with the attendant risk of future litigation should certain implants prove to be unacceptable as clinical results become available through the National Registry. Continuation with established practice may be acceptable, even in respect of implants not recommended by NICE, provided data collection activity is maintained. We propose an algorithm through which individual departments may maintain compliance with NICE without altering departmental practice.

Introduction The CPS-Plus stem (Endoplus UK) is a polished double-taper with rectangular cross section maintained throughout for rotational stability. There are 5 stem sizes with proportionate offset, and 5 neck length options. A unique proximal stem centraliser has been shown to increase proximal cement pressurisation during insertion in-vitro, also assists with alignment of the stem and helps create an even cement mantle. RSA analysis has demonstrated linear subsidence in a vertical plane, without posterior head migration and valgus tilt.

We report a multi-centre prospective clinical trial. 231 hips in 223 patients have been entered into the study. 151 of these have reached 3 years follow-up.

Method Patients were recruited by surgeons working at three centres in the UK, and two in Norway. Merle d Aubigne and Postel, Harris, and Oxford hip scores were recorded pre-operatively and at follow-up (3, 6, 12, 24, 36, 60 months). Radiographic assessment included evaluation of subsidence and the presence of any radiolucencies.

Results Hip scores have been very satisfactory. Radiological subsidence is less than 1.5mm in over 95% of cases and only one stem has subsided more than 3mm. There has been one revision for deep sepsis, 7 dislocations and one femoral fracture, but none of these complications were related to the choice of femoral component. There have been no revisions for aseptic loosening. Kaplan Meier survivorship analysis at 36 months for aseptic stem loosening is 0.997 (95% CI 0.977 – 1) and for all-cause revision is 0.981 (95% CI 0.958 – 1). 53 hips had reached 5-year follow-up at 30/9/04.

Discussion The tradition of polished tapered stems arose from serendipity and most results have been excellent. The CPS-Plus stem represents an attempt to re-examine the issues relating to rotational stability, subsidence, cement pressurisation and offset. Earlier laboratory studies have now been supplemented by this clinical evaluation, performed in a number of different centres by several surgeons, and the evidence is encouraging.

In particular, the RSA subsidence characteristics, cement pressurisation and rotational stability already associated with this implant in-vitro have been supported by excellent survivorship analysis, and the authors believe that increasing familiarity with the concepts raised by this implant will result in clinical benefits in relation to polished taper cemented stem longevity.