Introduction: We report our experience with use of the SMILES prosthesis in primary knee arthroplasty.

Methods: The Stanmore Modular Individualised Lower Extremity System (SMILES prosthesis) has been shown to be effective in complex revision knee surgery. It incorporates a rotating hinge platform knee joint and can overcome the major problems of bone loss and ligamentous laxity.

38 patients (41 knees) who received a primary SMILES knee prosthesis by one of the senior authors between 1990 and 2006 were retrospectively studied. Knee function was assessed pre and post-operatively using the Oxford knee score (0–48 scoring system) and the Knee Society Score. Patients receiving surgery for tumours were excluded. The main indications for primary SMILES were bone loss and ligamentous laxity.

Results: The minimum follow-up was 18 months with a mean of 5 years (1–17). The mean age of the patients was 57.7 years (23–86); 15 of the patients were male. The indications for surgery were trauma (12), osteoarthritis with deficient medial collateral ligament (8), polio (7), rheumatoid arthritis (5), epiphyseal dysplasia (4), achondroplasia (2), avascular necrosis (1), osteogenesis imperfecta (1) and ankylosing spondylitis (1).

2 patients died and 5 were lost to follow-up. 2 patients required revision surgery (one for infection and one for re-bushing). Post-operative complications included peroneal nerve palsy (1) and DVT (1). The mean Oxford knee score improved from 9 pre-op to 44 post-op, and the mean knee society score improved from 24 pre-op to 71 post-op. The average range of motion was 57 degrees pre-op and 88 degrees post-op.

Conclusion: We conclude that the SMILES prosthesis offers significant improvement in clinician and patient assessed outcome scores in complex primary knee arthroplasty. The cost compares favourably with other designs and its use is well established.

Our aim was to review the short-term clinical results of a single-institution cohort undergoing opening wedge high tibial osteotomy (HTO).

We undertook a prospective clinical and radiographic review of our cohort of patients who had undergone opening wedge HTO for varus malalignment. The Cincinnati scoring system was used for objective assessment. Pre- and post-operative radiographs were evaluated and Blackburne-Peel (BP) and Insall-Salvati (IS) ratios recorded, as well as integrity of the lateral hinge.

We reviewed 55 knees (51 patients: 34 men and 17 women; mean age, 44.2years; range 34–58years) followed up for a minimum 12 months (range, 12–62months). All patients had relief of pain, but six met our criteria of failed treatment where either revision fixation was required or proceeded to total knee arthroplasty for persisting symptoms. Cincinnati scores were 94.5% excellent (52/55) and 5.5% good (3/55) at 1 year, whilst at last follow-up they were 87.2% excellent (48/55), 9.1% good (5/55) and 3.6% fair (2/55). There was a significant improvement in mean American Knee Society score at 1 year and maintained at last follow-up (p< 0.05). Radiographically the lateral hinge was noted to be breached in 9.1% (5/55), but no incidence of non-union was identified. There was no significant change in IS index, however BP index diminished by a mean 15.3% (range, 7.4–28.2%). Opening wedge HTO provides a means of relieving stress distribution through the medial tibiofemoral compartment and results in effective relief of symptoms with improvement in functional outcome and quality of life.

Aim: To review the short-term clinical results of a single-institution cohort undergoing opening wedge high tibial osteotomy (HTO).

Method: We undertook a prospective clinical and radiographic review of our cohort of patients who had undergone opening wedge HTO for varus malalignment. The Cincinnati scoring system was used for objective assessment. Pre- and post-operative radiographs were evaluated and Blackburne-Peel (BP) and Insall-Salvati (IS) ratios recorded, as well as integrity of the lateral hinge.

Results: we reviewed 55 knees (51 patients: 34 men and 17 women; mean age, 44.2 years; range 34–58 years) followed up for a minimum 12 months (range, 12–62 months). All patients had relief of pain, but six met our criteria of failed treatment where either revision fixation was required or proceeded to total knee arthroplasty for persisting symptoms. Cincinnati scores were 94.5% excellent (52/55) and 5.5% good (3/55) at 1 year, whilst at last follow-up they were 87.2% excellent (48/55), 9.1% good (5/55) and 3.6% fair (2/55). There was a significant improvement in mean American Knee Society score at 1 year and maintained at last follow-up (p< 0.05). Radiographically the lateral hinge was noted to be breached in 9.1% (5/55), but no incidence of non-union was identified. There was no significant change in IS index, however BP index diminished by a mean 15.3% (range, 7.4–28.2%).

Discussion: Medial opening wedge tibial osteotomy results in patellar infera, but successful clinical and functional outcomes have been demonstrated. The fact there is inconsistency between the two indices assessing patellar height ratio we believe reflects the inherent variability in the techniques employed. Distalisation of the tibial tubercle will mean the IS ratio remains unaffected, whilst the BP index more accurately demonstrates the lowering of patella relative to the joint line. However there may be other factors which are not immediately appreciated, such as changes in the tibial inclination or antero-posterior translation.

Introduction: Blood management in the perioperative period of the total joint arthroplasty procedure has evolved over the last 3 decades. We performed two separate studies:

1) observational study to analyse surgeon’s and anaesthetist’s attitude to transfusion

Method: 500 orthopaedic surgeons and 336 anaesthetists were surveyed to assess current UK attitudes towards transfusion practice following arthroplasty.

200 patients (88 THR, 99 TKR, 13 hip resurfacing) were evaluated. Blood Hb, hand grip strength and vigour scores using fatigue questionnaire were estimated both preoperatively and at 3 days following surgery. POMS and the required duration of in-patient physiotherapy were also noted. The protocol for blood transfusion was for those with Hb less than 8 g/dL and/or post-operative symptoms attributable to anaemia.

Results: In an uncomplicated patient following total hip arthroplasty, 53.2% of surgeons and 63.1% of anaesthetists would transfuse at or below Hb of 8g/dL. Mean transfusion threshold in surgeons was 8.3g/dL compared to 7.9g/dL for anaesthetists (p< 0.01). 97% of surgeons transfused two or more units compared to 78% anaesthetists (p< 0.01). This threshold Hb increased if patient was symptomatic (surgeons 9.3g/dL, anaesthetists 8.8g/dL, p< 0.05), or if known to have pre-existing ischaemic heart disease (surgeons 9.0g/dL, anaesthetists 9.2g/dL, p< 0.05).

A greater fall in postoperative Hb correlated significantly with a greater reduction in post-operative vigour score (p=0.02). Also a greater fall in vigour score was found to correlate significantly with the duration of in-patient physiotherapy (p< 0.001). A reduction in Hb of > 4g/dL from the pre-operative Hb predicted a significantly higher reduction in vigour score (p=0.03). A weak correlation was seen between a fall in Hb and POMS (p=0.09).

A higher pre-operative Hb did not reduce the required duration of in-patient physiotherapy (p=0.72). There was no correlation between post-operative Hb and POMS (p=0.21) or duration of in-patient physiotherapy (p=0.20).

A higher pre-operative grip strength predicted an early date of discharge by the physiotherapists (p=0.02).

Conclusion: Haemoglobin level below 9g/dL is the most common ‘trigger’ for blood transfusion. Surgeons tend to be more aggressive in their attitude to transfusion. A fall in Hb of more than 4 g/dL has a detrimental effect on post-operative rehabilitation. Pre-operative grip strength measurements are valuable in predicting the rehabilitation potential of patients undergoing lower limb arthroplasty.

Introduction: Smoking is associated with impaired wound healing, delayed bony union following fractures and an adverse effect on the immune system. Furthermore, smoking is an important risk factor for the development pulmonary complications following major surgical procedures, as well as wound complications. We determined whether smoking had a deleterious effect on outcome after autologous chondrocyte implantation (ACI) in the treatment of ostechondral defects of the knee.

Methods: We identified 103 (54 females and 49 males) patients with a mean age of 34.2 (range 18 to 49) who had undergone ACI between January 2001 and August 2004 who also had their smoking status recorded. The patients were divided into 3 groups according to their smoking status. The Visual Analogue Score, Bentley Functional Rating Score and Modified Cincinatti Scores were used to assess function pre-operatively, 6 months and then yearly thereafter.

Results: Group 1 consisted of 31 smokers (mean pack years of 13.4), group 2 consisted of 63 non-smokers and group 3 contained 9 ex-smokers. In Group 1, the Modified Cincinatti Score pre-operatively, 6 months, 1 year and 2 years following surgery were 34.1, 42.6, 43.5 and 46.7 respectively. In group 2 the scores were 47.4, 59.6, 59.1, 65.3, and in group 3 the scores were 39.8, 50, 53.3, 51.8. At the 1 year check arthroscopy, the graft failure rate in group 1 was 12% and biopsies revealed mixed hyaline and fibrocartilage in only 25% (there were no patients with hyaline cartilage). There were no graft failures in group 2 and 43.8% of the biopsies performed were either hyaline (12.5%) or mixed hyaline and fibrocartilage (31.3%). The wound complication rate was 24% in group 1 and 8% in group 2.

Conclusions: The results of this study suggest that people who smoke have a worse functional outcome and a higher complication rate following chondrocyte implantation. This association has not been previously described and should be included in the pre-operative counselling of patients undergoing the procedure.

Introduction: Several studies have implicated excessive weight as a negative predictor of success of total knee arthroplasty. In addition, obese patients are known to have increased risk of wound complications after orthopaedic and general surgery. The purpose of this study was to compare the clinical and functional outcomes of autologous chondrocyte implantation for treatment of osteochondral defects of the knee performed in obese patients with those performed in non-obese patients.

Methods: We analysed the data on all our patients that have been followed up for a minimum of 2 years and had their height and weight recorded initially in our database. Functional assessment consisted of Bentley Functional Rating Score, Visual Analogue Score, and the Modified Cincinatti Scores (collected prospectively at 6 months, 1 year, 2 years and 3 years following surgery). Patients were placed into 3 groups according to their body mass index (BMI). Group A consisted of patients with BMI of 20 to 24.9, group B patients with BMI of 25 to 29.9 and Group C are patients with BMI of 30 to 39.9.

Results: There were 80 patients (41 males and 39 females) with a mean age of 35.4 (range 18 to 49). The mean BMI for the entire group was 26.6. The pre-operative, 6 month, 1 year, 2 year, and 3 year Modified Cincinatti Score in Group A (32 patients) was 54.4, 80.3, 82.7, 74.7 and 72.6. Similarly in Group B, the scores were 53, 41, 54, 56, 49.5 and in Group C the scores were 36.3, 36.3, 49.6, 36, and 35.7. The wound infection rate in Group A was 6.25%, in Group B was 17.6% and Group C was 14.3%.

Conclusions: Initial results from this study suggest that BMI is an important predictor of outcome after chondrocyte implantation. The group of patients that would gain most benefit from ACI are patients that are not overweight (defined by BMI in the range of 20 to 24.9). Further work is being carried out to support the hypothesis that surgeons should strongly consider not operating on patients unless the BMI is less than 25.

Introduction: ACI is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We report the minimum 2 year follow-up results of 192 patients randomised to autologous chondrocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) and matrix-induced autlogous chondrocyte implantation (MACI) for the treatment of osteochondral decfects of the knee.

Methods: 192 patients (mean age 34.2) were randomised to have either ACI (86 patients) or MACI (106 patients). 1 year following surgery patients underwent check arthroscopy (with or without biopsy) to assess the graft. Functional assessment was performed yearly by using the modified Cincinatti knee score, the Bentley functional rating score and the visual analogue score.

Results: 24 patients were excluded from the study as they underwent additional procedures (e.g. high tibial osteotomy). In the ACI group the modified Cincinatti score increased from 42.5 pre-operatively to 56.7, 54.1, and 60.4 at 1 year, 2 years and 3 years respectively. In the MACI group the Cincinatti scores increased from 46.0 pre-operatively to 59.9, 58.9, and 58.4. Arthroscopic assessment showed a good to excellent International Cartilage Repair Society score in 90.7% of ACI-C grafts and 68.4% of MACI grafts. Hyaline-like cartilage or hyaline-like with fibrocartilage was found in biopsies of 51.9% of ACI-C grafts and 25.9% of MACI grafts.

Conclusions: ACI grafts are more likely to produce hyaline-like or mixed hyaline-like cartilage and fibro-cartilage with better ICRS grades than MACI grafts. However, this does not translate to better a clinical functional outcome. More importantly, ACI and MACI had similar results that were maintained at 3 years.

We aimed to determine whether proximal femoral bone remodelling, as measured by DEXA scan for each Gruen Zone, differed for 3 different femoral stem designs. These were:

Group 1 – Triple taper polished (C-stem J& J DePuy)

Ethical Committee approval was obtained and all patients gave informed consent. All operations were performed by 3 surgeons using a standard lateral approach, third generation cementing technique and a standard post-operative regime.

Seventy-five patients were randomised prospectively using a stratified randomisation programme for known risk factors in bone density. The randomisation was stratified by age, sex, Charnley Group (A or B), BMI and femoral neck bone mineral density. There were 25 patients in each Group, 5 patients did not have complete data sets and were therefore withdrawn from evaluation.

The Groups were similar with regard to age, sex, BMI, BMD and Charnley Group. Patients were followed up at 3, 6, 12 and 24 months by Nurse Practitioners for clinical and radiological evaluation and DEXA scan at each time of follow-up. There were no catastrophic failures of sepsis or dislocation. All patients functioned well at 24 months by Harris Hip Score.

The bone remodelling pattern will be described for each stem design. Findings are summarised thus. In the lateral Gruen Zones the triple taper and collared stem design faired better and both behaved differently to the double taper design. In Gruen Zone 7, all stems demonstrated reduced bone density as compared to pre-operative scans but this was less with the triple taper design.

Aims: To compare the clinical and functional outcomes of autologous chondrocyte implantation for treatment of osteochondral defects of the knee performed in overweight, obese and patients of ‘ideal weight’as defined by their BMI.

Methods: We analysed the data on all our patients that have been followed up for a minimum of 2 years and had their height and weight recorded initially in our database. Functional assessment consisted of the Modified Cincinatti Scores (collected prospectively at 6 months, 1 year, 2 years and 3 years following surgery). Patients were placed into 3 groups according to their body mass index (BMI). Group A consisted of patients with BMI of 20 to 24.9, group B patients with BMI of 25 to 29.9 and Group C are patients with BMI of 30 to 39.9.

Results: There were 80 patients (41 males and 39 females) with a mean age of 35.4 (range 18 to 49). The mean BMI for the entire group was 26.6. The pre-operative, 6 month, 1 year, 2 year, and 3 year Modified Cin-cinatti Score in Group A (32 patients) was 54.4, 80.3, 82.7, 74.7 and 72.6. Similarly in Group B, the scores were 53, 41, 54, 56, 49.5 and in Group C the scores were 36.3, 36.3, 49.6, 36, and 35.7. The wound infection rate in Group A was 6.25%, in Group B was17.6% and Group C was 14.3%.

Conclusions: Initial results from this study suggest that BMI is an important predictor of outcome after chon-drocyte implantation. The group of patients that would gain most benefit from ACI are patients that are not overweight (defined by BMI in the range of 20 to 24.9). Further work is being carried out to support the hypothesis that surgeons should strongly consider not operating on patients unless the BMI is less than 25.

Aims: To investigate

the influence of histology on durability of cartilage repair following collagen-covered autologous chon-drocyte implantation (ACI-C) in the knee.

Patients and methods: The modified Cincinnati scores (MCRS) of eighty-six patients were evaluated prospectively at one year and at the latest follow-up (mean follow-up = 4.7yrs. Range = 4 to 7 years). Biopsies of their cartilage repair site were stained with Haema-toxylin and Eosin and some with Safranin O and the neo-cartilage was graded as hyaline-like (n=32), mixed fibro-hyaline (n=19) and fibro-cartilagenous tissue (n=35). Macroscopic grading of the repair tissue using the international cartilage repair society grading system (ICRS) was available for fifty-six patients in this study cohort. Statistical analyses were performed to investigate the significance of histology and ICRS grading on MCRS at 1 year and at the latest follow-up.

Results: The MCRS of all three histology groups were comparable at one year evaluation (p=0.34). However, their clinical scores at the latest follow-up showed a significantly superior result for those with hyaline-like repair tissue when compared to those with mixed fibro-hyaline and fibro-cartilagenous repair (p=0.05).

There was no correlation between the ICRS grading and MCRS either at one year (p=0.12) or at the latest follow-up (p=0.16). Also, the ICRS grading of the repair tissue did not correlate with its histological type (p=0.12).

Conclusion: We conclude that any form of cartilage repair gives good clinical outcome at one year. At four years and beyond, hyaline-like repair tissue produces a more favourable clinical outcome. Macroscopic evaluation using the ICRS grading system does not reflect the clinical outcome or its durability or the histological type of repair tissue.

Purpose: We report on minimum 2 year follow-up results of 71 patients randomised to autologous chon-drocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) for the treatment of osteochondral defects of the knee.

Introduction: ACI is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autolo-gous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes.

Results: 71 patients with a mean age of 33 years (15–48) were randomised to undergo either an ACI-C or a MACI. 37 had ACI-C and 34 MACI. The mean size of the defect was 5.0cm2. Mean duration of symptoms was 104.4 months (9–456). Mean follow-up was 33.5 months (24–45). Functional assessment using the modified Cincinnati knee score, the Bentley functional rating score and the visual analogue score was carried out. Assessment using the modified Cincinnati knee score showed a good to excellent result in 57.1% of patients followed up at 2 years, and 65.2% at 3 years in the ACI-C group; and 63.6% of patients at 2 years, and 64% at 3 years in the MACI group. Arthroscopic assessments showed a good to excellent International Cartilage Repair Society score in 81.8% of ACI-C grafts (22 patients) and 50% of MACI grafts (6 patients). Fisher’s exact test showed a p value of p=0.35 (not statistically significant). Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in biopsies of 56.3% of the ACI-C grafts (9 out of 16 patients) and 30% of the MACI grafts (3 out of 10 patients) after 2 years. Fisher’s exact test showed a p value of p=0.25 (not statistically significant).

Conclusion: At this stage of the trial we conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI.

Introduction and Aims: Allogenic blood transfusion is often required in lower-limb arthroplasty. The aims of this study were (1) to analyze the influence of anaemia on post-operative fatigue, hand grip strength, duration of in-patient physiotherapy and post-operative morbidity score (POMS) and (2) to investigate for prognostic factors to predict functional recovery following primary arthroplasty of the lower limb.

Patients and methods: This study was approved by the regional ethics committee. Two hundred patients (88 THR, 99 TKR and 13 hip resurfacing) were evaluated in this prospective trial. Blood haemoglobin concentration (Hb), hand grip strength and vigour scores using a validated fatigue questionnaire were estimated both preoperatively and at 3 days following surgery. Postoperative morbidity score (POMS) and the required duration of in-patient physiotherapy were also noted. The protocol for blood transfusion was for those with Hb less than 8 g/dL and/or post-operative symptoms attributable to anaemia.

Results: A greater fall in postoperative Hb correlated significantly with a greater reduction in post-operative vigour score (p=0.02). Also a greater fall in vigour score was found to correlate significantly with the duration of in-patient physiotherapy (p< 0.001). A reduction in Hb of > 4g/dL from the pre-operative Hb predicted a significantly higher reduction in vigour score (p=0.03). A weak correlation was seen between a fall in Hb and POMS (p=0.09).

A higher pre-operative Hb did not reduce the required duration of in-patient physiotherapy (p=0.72). There was no correlation between post-operative Hb and POMS (p=0.21) or required duration of in-patient physiotherapy (p=0.20).

A higher pre-operative grip strength predicted an early date of discharge by the physiotherapists (p=0.02).

Conclusion: We conclude that a fall in Hb of more than 4 g/dL has a detrimental effect on post-operative rehabilitation. Pre-operative grip strength measurements are valuable in predicting the rehabilitation potential of patients undergoing lower limb arthroplasty.

Aim: The aim of this study was to correlate the histology of cartilage repair site with long term clinical function.

Materials and methods: We have analyzed the clinical results of a cohort of patients who had collagen-covered autologous chondrocyte implantations performed since 1998. Our hypothesis was that the hyaline cartilage repair does influence the clinical outcome.

The modified Cincinnati scores (MCRS) of eighty-six patients were evaluated prospectively at one year and at the latest follow-up following ACI-C (mean follow-up= 4.7 years. Range= 4 to 7 years). All these patients underwent biopsies of their cartilage repair site performed at variable periods between six months and five years following ACI-C (mean=22.2 months). The neo-cartilage was graded as hyaline (n=32), mixed fibrohyaline (n=19), fibrocartilagenous (n=35) and fibrous (n=0).

Results: The clinical results showed that at one year, the percentage of patients with excellent and good results was 84.4, 89.5 and 74.3 respectively for those with hyaline, mixed fibro-hyaline and fibro-cartilagenous histology respectively. Their mean MCRS were 70.8, 72.4 and 66.2 respectively. This difference was not statistically significant (p=0.34).

However, their clinical scores at the latest follow-up demonstrated a significantly superior result for those with hyaline repair tissue when compared to those with mixed fibro-hyaline and fibro-cartilagenous repair tissue (p=0.05). The percentage of patients with excellent and good results for those with hyaline, mixed fibro-hyaline and fibro-cartilagenous repair was 75, 42 and 68.6 respectively. Their mean MCRS were 70.6, 56.8 and 63.9 respectively.

Conclusion: This study demonstrates that any form of cartilage repair would give good clinical outcome at one year. At four years and beyond, it appears that patients with hyaline repair tissue tend to show a more favourable clinical outcome whereas those who demonstrated mixed fibrohyaline and fibrocartilagenous repair would show less favourable clinical results.

Functional evaluations using the Harris hip scoring system and the delayed Trendelenberg test were performed on fifty randomly selected patients who had undergone cemented primary CPT total hip replacements (Zimmer UK) at least 12 months previously using Hardinge approach. The prosthesis used increases offset with femoral stem diameter but did not allow separate correction of neck offset.

Patients were grouped according to whether hip offset had been accurately reconstructed, increased or decreased. Their functional outcomes were compared. There was no significant difference (p value 0.57) in the final functional outcome between the three groups. Reconstruction of the hip using a standard cemented CPT prosthesis produced considerable variation in the reconstructed hip arthroplasty offset. This resulted in no functionally significant effect.

Accurate reconstruction of the hip joint offset in total hip arthroplasty may therefore not be as important in the early functional outcome as recently advocated.

Purpose: The purpose of this study was to use the thromboelastogram to determine whether autologous blood transfusion following primary total knee replacement surgery results in an alteration to systemic coagulation.

Methods: 44 patients were randomised to receive either Hartmann’s solution alone postoperatively (control group), or Hartmann’s solution and autologous blood at six hours (ABT group). Thromboelastogram measurements of systemic blood clotting were performed pre-operatively, and post operatively at 6h just prior to the commencement of the ABT, 6h 30mins, and 8h.

Results: At 8h post operation (2h post ABT), the ABT group when compared with the control group showed an earlier onset of coagulation (3.83 minutes versus 4.49 minutes, p=0.003) and the formation of a stronger clot as assessed by the TEG maximum amplitude (maximum clot strength 83.9mm versus 75.9mm, p< 0.001).

Conclusion: The transfusion of drained autologous blood following total knee replacement may lead to an exaggerated hypercoagulable postoperative state. Further investigation of this potentially serious consequence of autologous blood transfusion is required.

Background: Autologous chondrocyte implantation (ACI) was introduced over 15 years ago as a treatment for full-thickness chondral defects in the knee. Current understanding of ACI graft morphology and maturation in humans is limited. The aims of this study were determine the incidence of hyaline-like repair following ACI, and to clarify the relationship between repair morphology and clinical outcome.

Methods: A retrospective review of 194 ACI graft biopsies from 180 patients, and their clinical outcome was conducted. 154 Biopsies were performed 1 year after implantation and 40 biopsies were performed at 2 years. Three techniques of ACI implantation were used; Collagen covered ACI (ACI-C), periosteum covered ACI (ACI-P) and Matrix-Induced ACI (MACI).

Results: At 1 year, hyaline repair tissue was found in 48 (53%) ACI-C grafts, 7 (44%) ACI-P grafts, and 12 (36%) MACI grafts. The frequency of hyaline tissue found in biopsies performed at 2 years (84%) was significantly higher than those performed at 1 year (48.6%), p=0.0001, suggesting that grafts continue to remodel after the first year post implantation.

Clinical outcomes during the first two postoperative years did not vary according to repair morphology type, though hyaline repair was associated with better clinical outcomes beyond 2 years; At 1 year, good to excellent clinical scores were observed in 29 (78.4%) patients with hyaline-like repair, 23 (76.7%) patients with fibrohyaline repair, and 54 (74.0%) patients with fibrocartilage repair. By years 3 and 4 post-implantation, clinical scores further improved in patients with hyaline-like repair yet declined in those with fibrocartilage and fibrohyaline. The difference was significant at 3 years though not at 4 due to the small number of cases.

Conclusions: Achieving hyaline-like repair is critical to the longevity of cartilage repair. The finding of hyaline-like cartilage or fibrohyaline cartilage in 31 of 37 biopsies (84%) performed after 2 years is therefore encouraging and supports further use of the ACI technique.

Background: Autologous Chondrocyte Implantation (ACI) is widely used as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum cover technique include the use of porcine-derived type I/III collagen as a cover (ACI-C), and the use of a collagen bilayer seeded with chondrocytes (MACI).

Aim: To determine whether differences in clinical, arthroscopic and histological outcomes at 1 year exist between ACI-C and MACI techniques.

Methods: We have performed a prospective randomised comparison of ACI-C versus MACI for the treatment of symptomatic chondral defects of the knee on 91 patients of whom 44 received ACI-C and 47 received MACI grafts.

Results: Both treatments resulted in improvements of clinical scores after 1 year. Mean modified Cincinnati knee scores increased by 17.5 in the ACI-C group and 19.6 in the MACI group (p> 0.05). Arthroscopic assessments performed after 1 year demonstrated good to excellent ICRS graft repair scores in 79% of ACI-C grafts and 67% of MACI grafts. Hyaline-like or hyaline-like cartilage with fibrocartilage was found in the biopsies of 43% of ACI-C grafts and 36% of MACI grafts after 1 year. The rate of graft hypertrophy was 9% in the ACI-C group and 6% in the MACI group. The frequency of re-operation was 9% in each group.

Conclusions: We conclude that clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI techniques. While the MACI technique is technically attractive, further long-term studies are required before widespread adoption of this new technique.

Introduction and Aims: ACI (autologous chondrocyte implantation) using a periosteum cover was developed by Peterson et al. Recently, the technique has been developed using a Type I/Type III collagen membrane (Chondro-Gide). A second technique MACI (matrix-induced autologous chondrocyte implantation) has evolved using a membrane with chondrocytes seeded onto its surface. Aim is to review the one and two-year results of the first 159 patients at a single regional centre.

Method: The two-stage procedure was performed with a standardised, progressive rehabilitation program. Patients were assessed clinically at three, six, nine, 12 and 24 months (pain score, Modified Cincinnati, Bentley), and arthroscopically at 12 and 24 months.

Results: 159 patients have been assessed at one year and 101 patients at two years. Of those patients reviewed at one year, 110 patients had the ACI repair with Chondro-Gide, 31 patients had the ACI repair with periosteum and 18 patients had the MACI repair. Sixty-nine percent had good or excellent results at one year and 60% at two years.

These figures represent the early results of this study performed at this unit.

Conclusion: We propose that the ACI technique is valuable for selected patients with Chondral and osteochondral defects of the knee even with large and multiple defects in the articular cartilage.

Introduction and Aims: Uni-compartmental knee arthroplasty (UKA) is appropriate for one in three osteoarthritic knees requiring replacement. An accelerated protocol enables patients undergoing UKA to be discharged within 24 hours of surgery. Before such an approach is universally accepted it must be safe, effective and economically viable. A study was performed to compare the new accelerated protocol with current standard care in a state healthcare system.

Method: A single blind RCT design was used. Patients eligible for UKA were screened for NSAID tolerance, social circumstances and geographical location before allocation to either an accelerated recovery group (Group A) or a standard non-accelerated group (Group S). The accelerated protocol included dedicated pain management and discharge support. Primary outcome was the Oxford Knee Assessment at six months post-operation, compared using independent t tests. Pain, range of movement and incidence of complications were also recorded by assessors blind to group allocation. Cost effectiveness was calculated in quality life adjusted years (QLAY) using the Euroqual instrument. The study power was sufficient to avoid type 2 errors. The study was supported by a NHS Regional R& D grant.

Results: Forty-one patients (21 group A, 20 group S) were included. Groups had comparable age and patient profiles. Average discharge time was 37 hours (1.5 days) for group A and 114 hours (4.3 days) for group S. Pain on hospital discharge was similar for both groups. No significant difference was found between groups for pain or range of movement at any time, although patients in group S regained pre-operative flexion faster than group A. One major complication occurred in each group; one infection (group S) and one manipulation for poor movement (group A). The cost per QLAY for the new protocol was 59% of the standard care.

Conclusion: The new protocol allows for safe accelerated discharge from hospital after UKA. The approach is cost-effective and should help to increase the throughput of patients who require knee replacement.

Introduction and aims: Increasingly the accurate reconstruction of the hip in total hip arthroplasty is planned using pre-operative pelvic radiographs. The accuracy of reconstruction is assessed using post-operative pelvic radiographs. This study defines significant variations in the offset, hip joint centre and femoral head centre-trochanteric height relations in normal radiographs.

Method: One hundred standard normal pelvic radiographs were examined based on a defined criterion. The medial offset, the vertical height of hip joint centre with reference to the ischial tuberosity and the femoral head centre-trochanterc height relation were measured for both hips. The differences in measurements were evaluated to determine the normal variation in offset and the hip joint centre. The relationship of the femoral head centre to the tip of the greater trochanter was determined.

Results: On average, the right hip and left hip differed by 2.54mm in their offset .The standard deviation of differences was 2.31. Therefore the offset of one hip will predict the offset of the other hip to within 4.62mm, with 95% accuracy. If the reconstructed hip has an offset to within + 4.62 to – 4.62mm of the contra lateral side, then the offset should be considered to be reconstructed as normal. The average difference in height of the hip joint centres of right hip from left hip with reference to bi-ischial line was found to be 3.49mm. The standard deviation of differences was 3.15. Therefore the hip joint centre height measured in one hip will predict the hip joint centre height of the opposite hip to within 6.3mm with 95% accuracy. Thus the hip joint centre height of one hip may differ from the opposite hip by 6.3mm in normal individuals. The tip of greater trochanter was on average 8mm higher than the centre of rotation of the femoral head. The greater trochanter was not at the same level as the femoral head centre as commonly believed.

Conclusion: This study demonstrates considerable variation in the medial offset and the hip joint centre location on pelvic wall. The femur head centre is lower than commonly assumed. These factors should be taken into account when pre-operative planning using pelvic radiographs and assessing the quality of the post-operative reconstruction.

Aims: The objective of this study was to clinically assess the outcome of CADCAM femoral components in the revision hip replacement. Methods: Between 1991 and 2000, 125 revision total hip replacements using CAD-CAM femoral components were performed. Clinical assessment was performed using the Harris Hip score, by direct patient consultation, and telephone or postal questionnaire. Survivorship was defined as the requirement for revision. Results: The patients were reviewed at a mean of 5.2 yrs (1 to 10)

The mean Harris hip score increased from 44 points (range, 27 to 71 points) preoperatively to 71 points (range, 21 to 98 points) at the time of the most recent follow-up. 9 patients required subsequent revision; 4 for aseptic loosening, 1 for septic loosening and 4 for fracture of the femoral component. Conclusions: CAD-CAM technology provides a viable alternative to the challenge of revision hip surgery, with results comparable to other cementless techniques.

Mosaicplasty¹ and Autologous Chondrocyte Implantation² (ACI) are both modern cartilage repair techniques used to repair symptomatic articular cartilage defects in the knee, based on small osteochondral grafts and cultured chondrocytes respectively. The aim is the restoration of articular cartilage, but until now there is no data comparing the two methods.

100 consecutive patients aged 15–45 with a symptomatic articular cartilage lesion in the knee suitable for cartilage repair were randomised at arthroscopic assessment to undergo either mosaicplasty or ACI. 42 patients underwent mosaicplasty, 58 had ACI. Mean age at time of surgery was 31 years and the average defect size 4. 66 cm².

46% of the defects were post-traumatic, 19% had osteochondritis dissecans, 14% had chondromalacia patella and 16% had lesions of unknown aetiology. 53% had a medial femoral condyle lesion, 25% patella, 18% lateral femoral condyle, 3% trochlea and there was one defect of the lateral tibial plateau.

The mean duration of symptoms was 7. 2 years and the average number of previous operations (excluding arthroscopies) was 1. 5. Only 6 patients had no prior surgical interventions to the affected knee. The mean follow-up was 1. 7 years.

Patients were evaluated using Modified Cincinnati and Stanmore Functional rating systems, visual analogue scores and clinical assessment. Arthroscopy and biopsy was performed at one year and repair assessed with the International Cartilage Repair Society grading system.

Clinical results at one year showed 70% of mosaic-plasty patients and 87% of ACI patients had a good or excellent result. Arthroscopy at one year demonstrated more complete healing in ACI patients. Eleven (26%) of the mosaicplasty group subsequently failed clinically and arthroscopically, with peak failure at 2 years.

At one year follow-up, both techniques of articular cartilage repair can be useful in selected patients. ACI is preferred for lesions of the patella. Long-term follow-up is needed to assess the durability of articular cartilage repair using these methods, in particular mosaicplasty which showed signs of progressive failure over 2 years.

Autologous Chondrocyte Implantation’ (ACI) is a cartilage repair technique that involves implantation of cultured chondrocytes beneath a membrane of autologous periosteum. In this study a porcine biodegradable membrane was also used to assess its effectiveness. The aim is to restore articular cartilage to symptomatic defects, rather than initiating a fibrocartilagenous repair.

We undertook a prospective study of 125 consecutive patients who underwent ACI. Average age at the time of surgery was 30. 9 years (range 14 – 49), 55% of patients were male. The average size of the defect was 4. 35 cm².

44% of defects were attributable to known traumatic incidents, 2 1 % had osteochondritis dessicans, 18% chondromalacia patella, 12% had defects of unknown aetiology and 5% other.

The average duration of symptoms prior to this surgery was 7. 16 years. The mean number of previous operations (excluding arthroscopies) was 1. 6. Only 9 patients had no previous major surgery to the affected knee. 44% had defects of the medial femoral condyle, 31% patella, 20% lateral femoral condyle and 5% had a trochlea lesion. 26% of the defects were covered with periosteum and 74% with a porcine collagen membrane (chondrogide)

Minimum follow-up was six months, 70 patients had minimum follow-up of one year. Mean follow-up 18 months.

Patients were assessed using Modified Cincinnati and Stanmore Functional rating systems, visual analogue scores and clinical evaluation.

Arthroscopy and biopsy was performed at one year and the repair assessed using the International Cartilage Research Society grading system.

At one year follow-up overall 41 % patients had an excellent result, 48% good, 8% fair and 3% poor. For defects of the medial femoral condyle, 88% had a good or excellent result, 85% for the lateral femoral condyle and 80% for the patella.

61 patients were arthroscopically assessed at one year. 50/61 (82%) demonstrated ICRS grade 1 or 2 repair. Healing of the defect occurred with either a periosteum or chondrogide defect cover.

Results at one year suggest that ACI is a successful articular cartilage repair technique in selected patients. Long-term follow-up is required to assess the durability of the repair.

Many methods have been described over the past 5 years for repair of articular cartilage defects. The best reported results have been from the use of autologous chondrocyte transplantation (ACT)(1) and mosaicplasty.(2) There have, however, been no prospective clinical trials of these two methods. In this trial 70 patients were prospectively randomized to receive either autologous chondrocyte transplantation (37) or mosaicplasty (33) in the knee. 37 patients were female and 33 male. The average age was 32 years (16 – 44). The indications for surgery were persistent pain and mechanical symptoms in the knee with an isolated defect of the articular cartilage. 38 (56%) were post-traumatic, 12 (16%) due to osteochondritis dissecans, 10 (14%) due to previous meniscectomy, and 10 (14%) due to chondromalacia patellae. The size of the defects ranged from 2cm2 to 12cm2 (mean 4.8cm2). There were 35 defects on the medial femoral condyle, 13 on the lateral femoral condyle, 17 on the patella and 5 on the trochlear. 31 patients were undergoing primary surgery and 39 secondary surgery. All were independently reviewed using the Visual Analogue Pain Score, the Cincinatti Pain Score and the Stanmore Score. Patients were arthroscoped at one year with MRI scan and biopsies where possible.

Results: The visual analogue pain score improved overall from a mean of 5.4 (range 3.4 – 7.4) pre-operatively to 3.9 (1.8 – 5.1) at one year review. Similarly the Cincinatti pain score improved from 6.5 pre-operatively to 10.2 post-operatively and the Cincinatti function score improved from 46 to 62 at one year before sport commenced. Overall 71% (49) patients were excellent or good on the clinical scoring scales, 15% (11) were fair, and 14% (10) were poor. The 10 poor results were no different from the main group with regard to age, sex, pain level or site or size of lesion. However, 5 were secondary procedures, 2 had multiple lesions, and 3 had had previous ruptured anterior cruciate ligaments. Arthroscopy and biopsy of 21 lesions so far after one year has shown mature articular cartilage in 2, and immature cartilage in 19. In all cases there was bonding of the repair tissue to the underlying bone. This study is already clarifying the role of ACT and mosaicplasty in the management of cartilage defects in the knee and also the necessity for the use of periosteal covering membrane.

This study examined the reliability of pre-operative templating of the femur in total hip replacement (THR), and the accuracy of the templates provided by leading arthroplasty manufacturers. Templates are provided by arthroplasty manufacturers to be used with pre-operative radiographs as an aid to selecting the appropriate size of prosthesis that will allow an optimal cement mantle in THR. These templates vary in magnification from 10-20% (Mode 15%).

A retrospective review of the pre- and post-operative AP pelvis radiographs of 50 randomly selected patients who underwent THR in 1998 was performed. The radiographs were taken using the uniform standard technique. The magnification of the post-op radiograph was calculated by measuring the femoral head size. This was compared to the magnification of the pre-op radiographs using the ratio of the inter-teardrop distance. The post-operative radiographs were templated using a 15% template and compared to the size of prosthesis inserted.

The mean radiograph magnification was 22.5% (range 10.7 to 32.6%), with the majority (74%) between 20–25%. The 15% template oversized the prosthesis in 68% of cases. A 10% template would have been inaccurate in 96% of our sample group.

In a standard AP pelvis radiograph, the only variable that affects magnification is the extent to which the patient’s soft tissues raise the bony structures away from the plate. This variation in magnification renders preoperative templating of the femur in THR unreliable. Accuracy could be improved by using templates with a magnification of 22.5%.