The objectives of the study were to investigate demographic, injury and surgery/treatment-associated factors that could influence clinical outcome, following Autologous Chondrocyte Implantation (ACI) in a large, “real-world”, 20 year longitudinally collected clinical data set.

Multilevel modelling was conducted using R and 363 ACI procedures were suitable for model inclusion. All longitudinal post-operative Lysholm scores collected after ACI treatment and before a second procedure (such as knee arthroplasty but excluding minor procedures such as arthroscopy) were included. Any patients requiring a bone graft at the time of ACI were excluded. Potential predictors of ACI outcome explored were age at the time of ACI, gender, smoker status, pre-operative Lysholm score, time from surgery, defect location, number of defects, patch type, previous operations, undergoing parallel procedure(s) at the time of ACI, cell count prior to implantation and cell passage number.

The best fit model demonstrated that for every yearly increase in age at the time of surgery, Lysholm scores decreased by 0.2 at 1-year post-surgery. Additionally, for every point increase in pre-operative Lysholm score, post-operative Lysholm score at 1 year increased by 0.5. The number of cells implanted also impacted on Lysholm score at 1-year post-op with every point increase in log cell number resulting in a 5.3 lower score. In addition, those patients with a defect on the lateral femoral condyle (LFC), had on average Lysholm scores that were 6.3 points higher one year after surgery compared to medial femoral condyle (MFC) defects. Defect grade and location was shown to affect long term Lysholm scores, those with grade 3 and patella defects having on average higher scores compared to patients with grade 4 or trochlea defects.

Some of the predictors identified agree with previous reports, particularly that increased age, poorer pre-operative function and worse defect grades predicted poorer outcomes. Other findings were more novel, such as that a lower cell number implanted and that LFC defects were predicted to have higher Lysholm scores at 1 year and that patella lesions are associated with improved long-term outcomes cf. trochlea lesions.

Mechanical loading of joints with osteoarthritis (OA) results in pain-related functional impairment, altered joint mechanics and physiological nociceptor interactions leading to an experience of pain. However, the current tools to measure this are largely patient reported subjective impressions of a nociceptive impact. A direct measure of nociception may offer a more objective indicator. Specifically, movement-induced physiological responses to nociception may offer a useful way to monitor knee OA. In this study, we gathered preliminary data on healthy volunteers to analyse whether integrated biomechanical and physiological sensor datasets could display linked and quantifiable information to a nociceptive stimulus.

Following ethical approval, 15 healthy volunteers completed 5 movement and stationary activities in 2 conditions; a control setting and then repeated with an applied quantified thermal pain stimulus to their right knee. An inertial measurement unit (IMU) and an electromyography (EMG) lower body marker set were tested and integrated with ground reaction force (GRF) data collection. Galvanic skin response electrodes for skin temperature and conductivity and photoplethysmography (PPG) sensors were manually timestamped to the integrated system.

Pilot data showed EMG, GRF and IMU fluctuations within 0.5 seconds of each other in response to a thermal trigger. Preliminary analysis on the 15 participants tested has shown skin conductance, PPG, EMG, GRFs, joint angles and kinematics with varying increases and fluctuations during the thermal condition in comparison to the control condition.

Preliminary results suggest physiological and biomechanical data outputs can be linked and identified in response to a defined nociceptive stimulus. Study data is currently founded on healthy volunteers as a proof-of-concept. Further exploratory statistical and sensor readout pattern analysis, alongside early and late-stage OA patient data collection, can provide the information for potential development of wearable nociceptive sensors to measure disease progression and treatment effectiveness.

Introduction

Circumferential periosteal release is a rarely reported procedure for paediatric limb lengthening. The technique involves circumferential excision of a strip of periosteum from the metaphysis of the distal femur, tibia and fibula. This study aims to determine the mid to long-term effectiveness of this technique.

Background

Greater trochanteric pain syndrome (GTPS) is a common problem affecting 10–25% of the population. Physiotherapy, anti-inflammatories, corticosteroid injections and surgery have all been described in the management of GTPS, all with limited, temporal success. Extracorporeal shockwave therapy (ESWT) has been proposed as a potential management option for this difficult presentation.

The current study aims to ascertain the outcome of ACI with simultaneous transplantation of an autologous bone plug for the restoration of osteoarticular defects in the femoral condyle of the knee (‘Osplug’ technique).

Seventeen patients (mean age of 27±7 years), twelve with Osteochondritis dissecans (OD) and five with an osteochondral defect (OCD) was treated with unicortical autologous bone graft combined with ACI (‘Osplug’ technique). Functional outcome was assessed with Lysholm scores obtained for 5 years post-operatively. The repair site was evaluated with the Oswestry Arthroscopy Score (OAS), MOCART MRI score and ICRS II histology score.

The mean defect size was 4.5±2.6 SD cm² and mean depth was 11.3±5 SD mm. A significant improvement of Lysholm score from 45 (IQR 24, range 16–79) to 77 (IQR 28, range 41–100) at 1 year (p-value 0.001) and 70 (IQR 35, range 33–91) at 5 years (p-value 0.009). The mean OAS of the repair site was 6.2 (range 0–9) at a mean of 1.3 years. The mean MOCART score was 61 ± 22SD (range 20–85) at 2.6 ± 1.8SD years. Histology demonstrated generally good integration of the repair cartilage with the underlying bone. Poor lateral integration of the bone graft on MRI and low OAS were significantly associated with a poor outcome and failure.

The Osplug technique shows significant improvement of functional outcome for up to 5 years. This is the first report describing the association of bone graft integration with functional outcome after such a procedure.

Background

Structural and functional outcome of bone graft with first or second generation autologous chondrocyte implantation (ACI) in osteochondral defects has not been reported.

We investigated whether an alternative tension band wire technique will produce greater compression and less displacement at olecranon (elbow) fracture sites compared to a standard figure of eight tension band technique. Olecranon fractures are commonly treated with tension band wiring using stainless steel wire in a figure of eight configuration. However recently published studies have raised doubts over the validity of the tension band concept proving that the standard figure of eight configuration does not provide fracture compression when the elbow is flexed. We propose an alternative tension band technique where the figure of eight is applied in a modified configuration producing greater compression across the fracture.

An artificial elbow joint was simulated using artificial forearm (ulna) and arm (humerus) bones. The design simulated the action of the muscles around the elbow joint to produce flexion and extension. There were two arms to this investigation. (1) Standard tension band wire configuration with stainless steel. (2) Modified tension band wire configuration with stainless steel. The simulated elbow was put through a range of movement and sensors measured the compression at the articular and non-articluar surfaces of the fracture. Measurements were taken for compression with different weights applied to challenge both the techniques of tension band wiring.

Measurements from the non articular surface of the fracture demonstrated greater compression with alternative tension band technique. However it was not statistically significant (ANOVA). Compression at the articular surface of the fracture exhibited statistically significant (p<0.05) greater compression with the alternative technique. Neither technique produced greater compression during flexion of the simulated elbow.

The alternative tension band wiring technique proved superior in providing greater compression over the fracture site.

The aim of our review was to assess (health related) quality of life ((HR)QoL) after one-stage or two-stage revision for prosthetic joint infection (PJI). Although it is generally accepted that staged revisions are very strenuous for patients, little is known about the (HR)QoL after these procedures. We compared (HR)QoL scores with normative population scores to assess the magnitude of this problem.

Two authors performed a computerized systematic search in Embase, Cochrane and Pubmed. We included articles that reported: validated (HR)QoL questionnaires, one-stage or two-stage revision for PJI after total hip arthroplasty (THA), a minimum follow-up of 24 months and a minimum of ten patients. Methodological quality of all papers was assessed using the MINORS score. The systematic review was conducted according to the PRISMA statement.

The search produced 11195 hits. After selection, based on title and abstract, 18 full text papers were reviewed. Six articles were excluded. Twelve papers were selected for final assessment. All papers described two-stage revisions. The mean MINORS score for these studies was 9.8, indicating moderate study quality.

Seven articles reported WOMAC scores, with a total of 185 patients (74% response rate) having a mean general score of 73, with a mean follow-up of 65 months. The normative total WOMAC score for the general population (age 60–64) is 82.9, with a score of 100 being the best possible outcome.

Four articles described Short Form 36 (SF-36) results on a total of 159 patients (71.9% response rate). In these studies the physical component score (PCS) of the SF-36 was on average 39.6 and the mental component score (MCS) was on average 50.9, with a mean follow-up of 41 months. Normative data for the US population (age 55–64) are a PCS of 47.2 and an MCS of 51.8.

Four articles reported Short Form 12 (SF-12) scores on a total of 138 patients, with a mean PCS of 33.6 and a mean MCS of 51.7, with a mean follow up of 72.5 months. Normative data for the Dutch population (age 55–65) are a PCS of 48.3 and an MCS of 52.8. A score of 100 represents best possible health for both SF questionnaires.

Patients that underwent two-stage revision for hip PJI have substantially lower (physical component) (HR)QoL scores, when compared to the general population.

Summary

Randomised controlled study evaluating new bone formation in vivo in fracture non-unions by bone marrow derived stromal cells (BMSC). These cells do not show statistically significant new bone formation. Age of the patient during fracture, diabetes and doubling time had been observed to be correlated with fracture healing.

Statement of purpose:

A randomised clinical trial was undertaken to find out if treatment time and failure rate in children treated by the Ponseti method differed between below-knee vs above-knee cast groups.

Aim

To evaluate the efficacy of bone marrow derived stromal cells (BMSC) for the treatment of non-unions in fractures.

Background

Hip resurfacing has resurged in the last decade due to a renewed interest in metal on metal bearing. One of the proposed advantages is ease of revision of the femoral component. Short term functional results after femoral revision are similar to those after conventional total hip replacement. Survival and function after revision of the acetabular component only or of both components have not been reported. We aimed to assess hip function and implant survival after revision of the acetabular component for failed Birmingham hip resurfacing (BHR).

Objective

To compare the ability of a new composite bio-absorbable screw and two conventional metal screws to maintain fixation of scaphoid waist-fractures under dynamic loading conditions.

Hip resurfacing with metal-on-metal in patients with osteonecrosis (ON) raises concerns of early failure. This study addresses the hypothesis that osteonecrosis as a pre-operative diagnosis significantly increases the risk of failure following hip resurfacing. We analyzed data of 202 hips that underwent metal-on-metal hip resurfacing. In group 1 were 101 hips with a pre-operative diagnosis of osteonecrosis. In group 2 were 101 hips with other pre-operative diagnosis of osteoarthritis. Survival analysis with Cox regression was used to compare the revision risks of both groups. The mean age at operation was 42 years in osteonecrotic and 43 years in osteoarthritic group. The preoperative and postoperative hip scores were 62 and 96 for osteonecrotic group and 58 and 95 for osteoarthritic group, respectively. Survival analysis with revision for any reason as the endpoint was performed on the two groups which had identical follow-up periods. Survival at 10 years was 97.7% for osteonecrosis and 95.0% for osteoarthritis. The revision risk for patients with osteonecrosis was lower (0.37, 95% CI 0.07 – 1.82, Cox regression) but the difference was not significant (p = 0.19). Our study found no difference in revision risk in patients with osteonecrosis as compared to those with osteoarthritis

We aimed to assess the long term results of patients who underwent Autologous Chondrocyte Implantation (ACI) for osteochondral lesions of the talus. Between 1998 and 2006, 28 patients underwent ACI for osteochondral lesions of the talus. All these patients were prospectively reviewed and assessed for long term results. Outcomes were assessed using satisfaction scores, Mazur ankle score and the AOFAS score, and Lysholm knee score for donor site morbidity.

The 28 patients who underwent the procedure included 18 males and 10 females. Follow up ranged from 1–9 years. In all patients, there was an improvement in the Mazur and AOFAS ankle scores and the Lysholm scores showed minimal donor site morbidity. Improvement in ankle score was independent of age and gender. The better the pre-op score the less the difference in post-op ankle scores. Patients were unlikely to benefit with pre-op ankle scores over 75.

The mid to long term results of ACIs in the treatment of localised, contained cartilage defects of the talus are encouraging and prove that it is a satisfactory treatment modality for symptomatic osteochondral lesions of the talus. Complications are limited. However, in view of limited number of patients, a multi-centre randomised controlled study is required for further assessment.

Introduction: Spinous process osteotomy (SPO) and multiple laminotomy can be used for multi-level lumbar decompression. We conducted an experimental study to compare the effects of these two methods on spinal kinetics.

Method: Ten fresh calf spines (L2- sacrum) were mounted in dental stone and segmental motion of L3 relative to L5 was assessed using an electromagnetic 3-D motion detection system (FASTRAK, Polhemus, Colchester, VT, USA). Pure moments of 0, 2.5, 5, 7, and 10 Nm were used in flexion/extension, right/left lateral bending, and right/left axial rotation. The moments were generated by applying two equal and opposite forces (weights) to the perimeter of a plastic circular disc, which was fixed to the superior end plate of L3 by three screws. In five spines decompression was performed at L3/4 and 4/5 using standard laminotomy technique. Decompression using SPO was done at L3–5 through a unilateral approach in the rest. Segmental mobility between the two methods was compared using the Mann-Whitney test.

Results: Mean range of motion in the specimens before intervention was-lateral bending (32.70 ± 7.6 SD), rotation (13.10 ± 4.8 SD), flexion/extension (19.30 ± 7.1 SD). There was statistically significant difference between mean increase in lateral bending after SPO to that following laminotomy (4.00 ± 1.5 SD vs 0.60 ± 1.6 SD; p=0.008). Mean increase in flexion- extension after SPO was not significantly different from that after laminotomy (4.50 ± 1.1 SD vs 3.90 ± 3.8 SD; p= 0.75). There was no difference in the mean increase in axial rotation after SPO compared to that following laminotomy (7.90 ± 3.6 SD vs 6.80 ± 5.0 SD; p= 0.75).

Conclusions: Both laminotomy and SPO produced increased range of motion in a calf spine model. SPO produced significant increase in lateral bending although its clinical significance is unknown.

Ethics approval: none

Interest Statement: Local grant (Research Fund, Centre for Spinal Studies, Robert Jones and Agnes Hunt Hospital, UK

Introduction: Hip resurfacing is a renaissance of metal on metal hip arthroplasty. It preserves bone stock and a large head allows greater range of motion. This new technique is gaining popularity among patients and surgeons alike. We present a nine year follow up in the context of survival, function and complications.

Methods: We analysed follow up data of 4778 patients who have had hip resurfacing using Birmingham Hip resurfacing (Smith & Nephew, UK) in 37 countries. Patients were followed up annually using Oswestry hip score and any revisions were updated on the database at the Oswestry Outcome Centre. Function was analysed using multilevel modelling and Kaplan-Meier method used for survival analysis.

Results: There were 3193 males and 1585 females operated by 138 surgeons in 37 countries. The mean age was 52.8 years (13 – 87.8). Using hierarchical regression the annual hip scores were analysed. Overall function was significantly affected by pre op score and gender (p< 0.01). Age at operation had no effect on outcome score (p =.462).

We observed similar effect in individual domains of pain, mobility and range of motion. Survival of the implant at nine years with revision due to any reason was 93.5%. We observed a significant difference in survival of procedures done by pioneer surgeons and by non pioneering surgeons (p < 0.01) (log rank test). There were 119 complications of which there were 30 fractures, 21 occurring within the first six months of operation.

Conclusion: Nine year results of hip resurfacing arthroplasty look promising and are comparable to traditional hip arthroplasty. The difference between two surgeon groups could be due to a learning curve in the technique. Further follow up would be necessary to ascertain the long-term clinical effectiveness of this technique.

Objective: The adequacy of the cement mantle around various designs of impaction-grafted stems has been compared and deemed inadequate around the Exeter system. Yet, good clinical results have been reported. The conventional wisdom of solid cement mantles has been also been questioned in recent reports by the low migration and high survival rates of stems inserted with a very thin cement mantle – the so called ‘French paradox’. We performed this study specifically to address two questions

Does cement mantle thickness affect cement penetration depth during impaction grafting? and

Materials and Methods: 12 composite femurs were prepared to mimic cavitary defect. Impaction grafting was done with morcellized freshly frozen porcine femoral condyles using Exeter X-change system. The size of tamp and prosthesis were independently varied creating tamp/stem mismatch to produce cement mantles with a nominal thickness of 0, 1, 2, 3 or 4 mm. Cyclical loading was done at 1 Hz for 2500 cycles at 2500 N. From the displacement data measured by 6 linear displacement transducers we calculated subsidence and retroversion. The solid cement mantle and the penetration depth into the graft were then measured along 16 points in each cut section of the femurs done at 1.5 cm intervals.

Results: There was a high correlation between tamp/stem mismatch (nominal mantle thickness) and actual mantle thickness (r=0.84). Average cement penetration into the graft for each prosthesis varied between 0.3 and 2.0 mm. Largest variations were proximally, where average penetration varied between 0.4 and 3.5 mm. A thicker solid cement mantle gave on average less cement penetration (r=−0.62). Stem subsidence after cyclic loading ranged from 0.4 to 2.5 mm and correlated significantly with tamp size (r=0.59, p< .05). However, better correlations were found with solid mantle thickness (r=0.90, p< 0.05) and cement penetration depth (r=−0.81). Stem retroversion after cyclic loading ranged from 0.1 to 2.0 degrees and correlated negatively with stem size (r=−0.53) but did not correlate with tamp size. Correlations with solid mantle thickness and cement penetration depth were not better than those with tamp size.

Discussion: Our study shows that a thinner mantle is associated with deeper cement penetration into the graft. This probably is due to the higher cement pressure generated during stem insertion when there is less space for the cement to escape. Better mechanical interlock with the higher cement penetration possibly explains the reduced subsidence with thin cement mantles. Our study also shows that stem retroversion is associated with stem size only, and is larger for thinner stems. This could be explained by thinner stems providing less resistance to torsional forces.

The adequacy of cement mantles around some impaction-grafting systems has been criticised yet good clinical results have been reported. This study investigates this contradiction by asking

Does cement mantle thickness affect cement penetration depth?

Twelve artificial femora were prepared to simulate cavitary defects. Porcine cancellous bone was morselized. The defect was reconstructed by impaction grafting, using a size 0, 1 or 2 tamp. Bone cement was injected, and a size 0, 1 or 2 Exeter stem inserted. By using all nine tamp/prosthesis combinations, 0–4 mm thick cement mantles were produced. Femora were positioned in a testing machine and loaded with 2500 cycles of 2500 N. Prosthesis subsidence and retroversion were measured. Each femur was sliced transversely and the sections digitised. Solid cement mantle thickness and cement penetration depth were measured using image analysis. Correlation analysis was used to find if tamp/stem mismatch (nominal mantle thickness) influenced actual solid mantle thickness and cement penetration. We then analysed if tamp size, stem size, solid mantle thickness or cement penetration determined stem subsidence and retroversion.

Cement mantles were produced with an average thickness of 1.7–2.2 mm, with largest variations proximally (1.5–2.8 mm). Average cement penetration was 0.3–2.0 mm, with largest variations proximally (0.4–3.5 mm). Thicker solid mantles gave less penetration (r=−0.62). Stem subsidence ranged from 0.4–2.5 mm and correlated significantly with tamp size (r=0.59, p< .05). Better correlations were found with solid mantle thickness (r=0.90, p< 0.05) and cement penetration depth (r=−0.81). Stem retroversion ranged from 0.1–2.0 degrees and correlated with stem size (r=−0.53) but not with tamp size.

Tamp/stem mismatch determined the thickness of the solid cement mantle around impaction-grafted stems, and thinner mantles were associated with deeper cement penetration. Thinner mantles and deeper penetration were associated with reduced stem subsidence. Stem retroversion was associated with stem size only, and larger for thinner stems. Thinner cement mantles will therefore be associated with deeper penetration and reduced stem subsidence upon loading. This association may explain the good long-term results of impaction-grafted Exeter stems, despite deficient solid cement mantles.

Background: Tension Band wiring technique is commonly used to treat transverse patella fractures. The commonly used configuration has parallel K wires and a stainless steel wire loop oriented as a figure of 8. Use of non-metallic suture materials as reliable fixation materials have been reported. We investigated the properties of composite polyester suture (Fibre wire) when used in Tension band wiring of patella.

Methods: A wooden model of a transversely fractured patella was used. The fracture was fixed using two K wires and a loop of horizontally oriented stainless steel wire or fibre wire. Two wire twists placed at corners were used for SS wire loops. For fibre wire samples a tensioning device was used and the knots placed at one corner. Interfragmentary compression at the point of wire breakage and fracture displacement on physiologic cyclic loading was measured for each fixation construct. The reliability of tensioning device (Arthrex) and the effect of using multiple strands of wire were assessed.

Results: Use of the tensioning device produced interfragmentary compression that could be repeated reliably. The addition of a further strand increased the interfragmentary compression developed by 94%. There was no significant difference between interfragmentary compression developed between groups (p> 0.05). The average interfragmentary compression produced for three repetitions for the individual groups, Fibre wire (1394N), SS wire of 1.0mm diameter (1320N), SS Wire of 1.25mm diameter (1594N) were comparable. This increased significantly when a second loop of fibre wire was used (2566N). Permanent fracture displacement at physiologic loads were, Fibre wire (9.7mm, SD 2.7mm), SS wire of 1.0mm diameter (7.0mm, SD 1.0mm) and SS Wire of 1.25mm diameter (7.4mm, SD 2.3mm). The addition of the second strand of fibre wire decreased the displacement significantly (4.8mm, SD 0.6mm). The effect of second strand of fibre wire decreased the displacement by 97% while the decrease on addition of the second strand of stainless steel wire was only 14%.

Discussion: Interfragmentary compression produced to failure was comparable between a single strand of fibre wire, 1.0mm SS wire and 1.25mm SS wire, the commonly used SS wire diameters in fixation of fractured patella. The standard deviations of final permanent displacement were higher with the larger diameter of SS wire, indicating that the use of a thicker wire would require some preloading before it is uniformly tensioned. Amongst the SS wire diameters tested, 1.0mm resulted in least variations (SD 1.0mm).

The addition of second strand resulted in a marked improvement in displacement with Fibre wire and variations between different samples were smaller than in any other group tested (SD 0.6mm)

Conclusions:

Fibre wire has similar strength to failure when compared the commonly used thickness of stainless steel wire for fixation of patella.