Objective: To ascertain the epidemiology of ankle injuries in elite youth football.

Design: Retrospective analysis of prospectively collected injury data from English Football Association Academies.

Setting: Forty-one FA Football Academies, between 1998 and 2006.

Participants: For the complete seasons studied, a total of 14776 players were registered from U9 to the U16 age category – a mean of 2463 players per year. All ankle injuries of sufficient severity to miss 48 hours or more training were studied – 2563 injuries in total.

Main outcome measurements: The incidence and burden of ankle injuries in this population, and factors associated with injury.

Results: There was a mean incidence of one ankle injury per player per year, and a mean of 20 training days and 2 matches were missed per ankle injury. Increased injury rates were seen in older players, in competition and later in each half of match time. Peaks in injury were observed early in the season and after the winter break. In competition, more injuries were associated with a contact situation than in training. Eighty-eight injuries (3.4%) required a lay-off of three months or more and in 18 (0.7%) cases, the player failed to return to training. In total, 52290 training days and 5182 match appearances were lost through ankle injury. The majority of injuries were sprains, but more severe injuries occurred accounted for 3.9% of the total.

Conclusions: Ankle injuries are common in young football players, and are often severe, with prolonged loss of training time. This has potential far reaching implications, both on and off the field. Further syudy in this area is suggested.

We have attempted to quantify the influence of clinical, radiological and prosthetic design factors upon flexion following knee replacement. Our study examined the outcome following 101 knee replacements performed in two prospective randomized trials using similar cruciate retaining implants. Multivariate analyses, after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates for range of movement at 12-months were the difference in posterior condylar offset ratio (p< 0.001), tibial slope (p< 0.001) and preoperative range of movement (p=0.025). We found a moderate correlation between 12-month range of movement and posterior tibial slope (R=0.58) and the difference of post femoral condylar offset (that is, post-operative minus preoperative posterior condylar offset, R=0.65). Posterior condylar offset had the greatest impact upon final range of movement highlighting this as an important consideration for the operating surgeon at pre-operative templating when choosing both the design and size of the femoral component.

Introduction: Correct alignment in both coronal and sagittal planes has been shown to be associated with longevity of total knee arthroplasty. The majority of procedures are performed using an intramedullary rod with a femoral cutting jig, with a 5°–7° offset depending upon the anatomical and mechanical axes. The cutting jig rotates around the rod and therefore the rotational alignment of the jig will also affect the cut and final component position (in addition to the rod entry point). It is interesting that rotational alignment of the femoral component is often assessed after the distal resection has been made. The distal resection plane determines the final position of the femoral component, influences patellar tracking and medial/lateral, flexion/extension balancing. This study measures the resultant effect on the distal femoral resection when entry point and jig rotation are varied.

Materials and Methods: The distal femoral resection was carried out in sawbones with three different entry points (central, inferior and superolateral) in neutral alignment and rotations of 10° (internal and external) about the transepicondylar axis. The resulting plane of the cut was assessed by a graphical method measuring the changes in orientation of the alignment rod in space before and after the distal cut. A computer navigation system was used to measure the varus/valgus and flexion/extension angles of the distal cut. This experiment was done thrice, in a total of 27 sawbones and the average values were recorded.

Results: The results varied considerably in the sagittal plane with central and inferior entry points. Internal rotation of the jig around a central entry point produced hyperextension (mean 3.3°) and external rotation caused flexion (mean 1.8°). Using an inferior entry point, flexion of the distal plane improved from an average 3° in neutral rotation to 1.6° on internal rotation; external rotation worsened flexion to an average of 4.3°. The angles digressed in both sagittal and coronal planes with a superolateral entry point; rotations of the distal cutting jig caused hyperextension (maximum of 7.5°). Coronal alignment ranged from 4.5° of varus to 5° of valgus in neutral alignment and rotations around a superolateral entry point.

Conclusion: The study demonstrates that there is a possibility of a compound error from misplaced entry point and that malrotation prior to distal resection is real. This error would invariably be extrapolated in the subsequent steps of conventional knee arthroplasty. Computer assisted arthroplasty may have a role in avoiding this surgical error.

Surgical reconstruction of the injured Anterior Cruciate Ligament (ACL) is an effective solution to knee instability, but not all grafts incorporate well. The biological environment in the knee that controls graft integration is not well understood, and this study aims to fill that gap as the first step towards a translational approach to optimise outcomes.

Over two stages, tissue samples and knee fluid samples were harvested from patients undergoing ACL reconstruction. These samples were cultured and stored to allow batch analysis for a variety of cytokines, growth factors and collagenases.

Stage 1 (n=14) identified the presence of specific pro-inflammatory cytokines, growth factors and latent collagenase. Information gathered allowed a more targeted approach to be used in stage 2 (n=18). Stage 2 data from tissue cultures suggest that collagenase activity peaks later than 6 hours post-op. The relationships between collagenase activity and levels of TNF-alpha, IL-1beta and bFGF are of potential interest, and the profiles of patients will be compared with longer term follow-up data to determine any effects on outcomes.

Further detailed assessment of the biology of ACL graft incorporation is required, but these preliminary data have clarified some of the details worthy of further study.

The Kinemax Plus knee replacement has a reported 10 year survival of around 96%. However we found the survival rate of this implant in our cohort to be 75% at 9 years. No abnormalities were found for clinical and radiological parameters. At reoperation the most striking feature was that of significant ultra-high molecular weight polyethylene (UHMWPE) failure. Oxidative and structural analysis of the polyethylene components was therefore undertaken.

Ten Kinemax Plus tibial inserts were analysed; one was a shelf-aged unused implant, the others were explants. An FTIR analysis of the data showed that oxidation is present in all samples. The degree of oxidation however varied with depth and location. Except for a sharp oxidative peak approximately half way into the sample, the shelf aged samples had a fairly constant level of oxidation. The retrieved implants had an overall higher level of oxidation in both bearing and non-bearing regions. The latter had less of a variation in oxidation which implies that in vivo loading exaggerates the degree of oxidation. In the non-articulating regions oxidation of the explants was found to peak often at the region of about 40% from the bottom surface in all retrieved samples. By contrast, most articulating region had two oxidative peaks; one occurring at approximately 1–1.5mm from the surface, which is consistent with findings on subsurface oxidation, and another occurring about 2–3mm from the bottom surface.

SEM imaging provided evidence for the presence of fusion defects by indicating grain boundaries through-out the explants. This indicates a compromised material which is more susceptible to damage. Fatigue loading of the implant has also been seen to produce a subsurface stress maximum at approximately 1 to 2mm below the articulating surface. It is thought that maximum contact stresses within this region cause Type 1 and Type 2 defects to open or become more pronounced. This in turn will increase the local concentration of oxygenating material as it will be present in these defects and voids where surface areas are greater for oxidative reaction. We therefore hypothesise that these fusion defects are the cause for the early failure of the Kinemax implants.

We aim to explain the significant difference in survivor-ship found between two cohorts of patients who underwent different total knee replacements. The first cohort included 70 patients who underwent Kinemax Plus total knee replacement, the second cohort included 58 patients who underwent PFC Total Knee replacement. All patients were under the care of one Consultant Orthopaedic Surgeon.

Interestingly, the Kinemax Plus cohort was found to have a higher rate of revision as compared to the PFC cohort. A detailed comparison was then carried out between the two groups to identify any obvious cause for the disparity.

The two cohorts were found to be well matched with respect to age, sex, ASA grade, underlying pathology and operative technique. Median follow up being 6 years and 5 years for the Kinemax and PFC groups respectively. There were 11 failed prostheses in the kinemax cohort, 7 undergoing revision with the remaining 4 patients offered revision but unwilling have surgery. Wear of the polyethylene tibial insert was the most obvious finding at revision, present in six out of the 7 revisions. 97% of the Kinemax Plus Prostheses were intact at 5 years but by 8 years only 87% were intact.

There were no revisions performed in the PFC cohort.

Post operative x-ray analysis was undertaken to rule out prosthesis misalignment as a cause for the increased failure rate. The coronal alignment of the prostheses (CAK) was calculated and all post operative x-rays were within the normal limits of 4–10 degrees.

Analysis of the explanted Kinemax Plus polyethylene liners was undertaken. In six cases, the polyethylene bearing surfaces displayed severe surface and subsurface delamination at both medial and lateral sides. This suggests massive fatigue and fatigue wear. Only one inplant showed localised delamination. The surface characterisation suggests the hypothesis of weak UHMWPE particle interface strength.

Objective: The aim of the study was to test the hypothesis that insertion of a total knee replacement (TKR) may effect range of motion as a consequence of excessive stretching of the retinaculae.

Methods: 8 fresh frozen cadaver knees were placed on a customised testing rig. The femur was rigidly fixed allowing the tibia to move freely through an arc of flexion. The quadriceps were loaded to 175N in their physiologic lines of action using a cable, pulley and weight system. The iliotibial tract was loaded with 30N. Tibiofemoral flexion and extension was measured using an optical tracking system. Monofilament sutures were passed along the fibres of the medial patellofemoral ligament (MPFL) and the deep transverse band in the lateral retinaculum with the anterior ends attached to the patella. The posterior suture ends were attached to ‘Linear Variable Displacement Transducers’. Thus small changes in ligament length were recorded by the transducers. Ligament length changes were recorded every 10° from 90° to 0° during an extension cycle. A transpatellar approach was used when performing the TKR to preserve the medial and lateral retinaculae. Testing was conducted on an intact knee and following insertion of a cruciate retaining TKR (Genesis II). Statistical analysis was performed using a two way ANOVA test.

Results: The MPFL had a mean behaviour close to isometric, while the lateral retinaculum slackened by a mean of 6mm as the knee extended from 60 degrees (Fig 1). After knee replacement there was no statistically significant difference seen in ligament length change patterns in the MPFL, however the lateral retinaculum showed significant slackening from 10 to 0°.

Conclusion: The data does not support the hypothesis that insertion of a TKR causes abnormal stretching of the retinaculuae. This result relates specifically to the TKR design tested.

Background: The determinants of range of movement following knee replacement may be surgically modifiable (tibial slope, posterior condylar offset or the level of the joint line) or non modifiable (pre-operative range of movement, sex or BMI). We aimed to quantify the influence of these factors upon restoration of flexion in the arthritic knee following knee replacement

Methods: Patients were included from two prospective trials for three different designs of knee replacement. Range of movement was recorded using a standard measuring technique preoperatively and 12 months after surgery. Radiological measurement was done by an independent observer and included the preoperative posterior condylar offset and the postoperative tibial slope, posterior condylar offset, posterior condylar offset ratio, varus-valgus alignment and Insall ratio. Multivariate analysis using stepwise selection was performed to determine the significant predictors of the range of movement at 12 months.

Results: The study includes 133 knee replacements performed on 125 patients. Complete clinical and radiographic data for preoperative and 12-month assessment was available for 101 knees and only these were included for the analyses. There was no significant difference between the three groups in terms of postoperative range of movement or the radiological parameters measured. Multivariate analysis after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates of range of movement at 12-months were the difference in posterior condylar offset ratio, tibial slope and preoperative range of movement. Moderate correlation was noted between range of movement at 12 months and posterior tibial slope (R=0.58) and the difference of post femoral condylar offset (that is, post-operative minus preoperative posterior condylar offset, R=0.65). Preoperative range of movement had only a weak correlation with post-operative range of movement (R=0.20).

Conclusions: We found that the posterior femoral condylar offset had the greatest impact upon final range of movement. We would encourage the operating surgeon at pre-operative templating to take this into account when choosing size and design of femoral component.

Objective: The aim of this study was to test the hypothesis that malrotation of the femoral component following total knee replacement (TKR) may lead to patellofemoral complications as a consequence of excessive stretching of the retinaculae.

Methods: 8 fresh frozen cadaver knees were placed on a customised testing rig. The femur was rigidly fixed allowing the tibia to move freely through an arc of flexion. The quadriceps and iliotibial tract were loaded to 205N in their physiologic lines of action using a cable, pulley and weight system. Tibiofemoral flexion and extension was measured using an optical tracking system. Monofilament sutures were passed along the fibres of the medial patellofemoral ligament (MPFL) and the deep transverse band in the lateral retinaculum with the anterior ends attached to the patella. The posterior suture ends were attached to ‘Linear Variable Displacement Transducers’. Thus small changes in ligament length were recorded by the transducers. Ligament length changes were recorded every 10° from 90° to 0° during an extension cycle. A transpatellar approach was used when performing the TKR to preserve the medial and lateral retinaculae. Testing was conducted following insertion of a cruciate retaining TKR (Genesis II). The femoral component was rotated using a custom built intramedullary device. Ligament length changes were measured at neutral rotation, 5° internal and 5° external rotation. Statistical analysis was performed using a two way ANOVA test.

Results: Internal rotation resulted in the MPFL slackening a mean of 1.7mm from 70-0° extension (p< 0.001). External rotation resulted in the MPFL tightening a mean of 1.5mm over the same range (p< 0.01). The lateral retinaculum showed less significant differences.

Conclusion: External rotation resulted in smaller length changes than internal rotation. Patellar tilting as a result of internal rotation may be caused by MPFL slackening and not lateral retinacular tension, contrary to popular understanding.

Objective: This study tested the hypothesis that complications resulting from overstuffing the patellofemoral joint after total knee replacement (TKR) may be a consequence of excessive stretching of the retinaculae.

Methods: 8 fresh frozen cadaver knees were placed on a customised testing rig. The femur was rigidly fixed and the tibia moved freely through an arc of flexion. The quadriceps and iliotibial tract were physiologically loaded to 205N using a cable, pulley and weight system. Tibiofemoral flexion/extension was measured using an optical tracking system. Monofilament sutures were passed along the fibres of the medial patellofemoral ligament (MPFL) and the deep transverse band in the lateral retinaculum with the anterior ends attached to the patella. The posterior suture ends were attached to ‘Linear Variable Displacement Transducers’. Thus, small changes in ligament length were recorded by the transducers. Length changes were recorded every 10° from 90°- 0° during an extension cycle. A transpatellar approach was used when performing the TKR to preserve the medial and lateral retinaculae. Testing was conducted following insertion of a cruciate retaining TKR (Genesis II). The patella was resurfaced and various patellar thicknesses were achieved by placing 2mm thick nylon washers behind the ‘onlay’ button. The thicknesses measured were 2mm understuff, pre-cut thickness, 2 and 4mm overstuff. Statistical analysis was performed using a two way ANOVA test.

Results: Patellar understuff resulted in the MPFL slackening an average of 1.6mm from 60 to 0° (p< 0.05). Overstuffing the patella 2mm resulted in no significant length changes whereas 4mm overstuff resulted in a mean increase in MPFL length of 2.3mm throughout extension (p< 0.001). No significant length changes seen in the lateral retinaculum

Conclusion: Overstuffing the PFJ stretches the MPFL, because it attaches directly between two bones. The lateral retinaculum attaches to the relatively mobile ITT, so overstuffing does not stretch it.

We describe a cohort of patients with a high rate of mid-term failure following Kinemax Plus total knee replacement inserted between 1998 and 2001. This implant has been recorded as having a survival rate of 96% at ten years. However, in our series the survival rate was 75% at nine years. This was also significantly lower than that of subsequent consecutive series of PFC Sigma knee replacements performed by the same surgeon. No differences were found in the clinical and radiological parameters between the two groups. At revision the most striking finding was polyethylene wear. An independent analysis of the polyethylene components was therefore undertaken. Scanning electron microscopy revealed type 2 fusion defects in the ultra-high molecular weight polyethylene (UHMWPE), which indicated incomplete boundary fusion. Other abnormalities consistent with weak UHMWPE particle interface strength were present in both the explanted inserts and in unused inserts from the same period.

We consider that these type 2 fusion defects are the cause of the early failure of the Kinemax implants. This may represent a manufacturing defect resulting in a form of programmed polyethylene failure.

We report the results of a prospective randomised controlled clinical trial assessing the radiosterophotogrametric analysis (RSA), clinical and radiological performance of a metal backed and an all-polyethylene tibial cruciate retaining, condylar design, PFC-TKA up to twenty four months.

65 patients were recruited, of which 41 patients were randomised. There were 20 metal backed and 21 all-polyethylene. None were lost to follow-up. There were no significant inter-group demographic differences. We found a significant increase in SF-12 and Oxford knee scores after surgery in both groups. No significant difference was found between the groups in the RSA, SF-12, Oxford Knee score, radiological alignment and range of movement at 6, 12 or 24 months. At 2 years one metal backed implant showed translational migration > 1mm. No all polyethylene implant migrated > 1mm. Further analysis identified possible progressive subsidence of the metal backed implants compared to all-polyethylene implants, although the magnitude of this difference was very small.

We conclude that in the uncomplicated primary total knee arthroplasty, all polyethylene PFC-_ tibial prostheses had equivalent performance to the metal backed counterpart, using RSA as the primary assessment instrument at 24 months. We found no differences between the two designs as assessed by the secondary instruments: SF-12, Oxford knee score, alignment and range of movement at 24 months. Should half of all primary total knee replacements performed in the UK receive an all-polyethylene tibial implant, the estimated annual cost saving would be 21 million pounds per annum.

Aim: To analyse the posterior and external rotational laxities in single bundle PCL (sPCL) and double bundle PCL reconstruction (dPCL) in a PCL and PLC deficient knee.

Methods: Ten fresh frozen were used. A custom made wooden rig with electromagnetic tracking was used to measured knee kinematics. Each knee was tested with posterior and anterior drawer forces of 80N and an external rotation moment of 5Nm when intact, after PCL resection, after dividing the PLC and after performing dPCL and sPCL reconstructions with a bone patellar tendon bone allograft and tibial inlay technique.

Results: The one-tailed paired Student’s t test with Bon-ferroni correction was used. There was a significant difference between the ability of the dPCL and sPCL reconstruction to correct the posterior drawer in extension (p=0.002). There was no difference between the dPCL reconstruction and the intact condition of the knee near extension (p=0.142, Fig 1). There was no significant difference between the intact condition and both sPCL (p=0.26) and dPCL (p=0.20) reconstructions in flexion in restoring posterior laxity. Neither of the reconstructions could restore the rotational laxity (Fig 3).

Conclusion: In a combined PCL and PLC deficient knee the posterior laxity can be controlled by both the sPCL as well as the dPCL reconstructions except near extension where the dPCL reconstruction was better.

Aim: To compare the ability of two different PLC reconstruction techniques to restore the kinematics of a PCL & PLC deficient knee to PCL deficient condition.

Methods: 8 fresh frozen cadaver knees were used. A custom rig with electromagnetic tracking system measured knee kinematics. Each knee was tested with posterior & anterior drawer forces of 80N, external rotation moment of 5Nm & varus moment of 5Nm when intact, after dividing PCL, PLC (lateral collateral ligament & popliteus tendon), after PLC reconstruction type1 (1PLC) & PLC reconstruction type 2 (2PLC). 1PLC was modification of Larson’s technique with semitendinosus graft. 2PLC was performed with semitendinosus graft to reconstruct the lateral collateral ligament & the pop-liteofibular ligament, gracillis used to reconstruct pop-liteus tendon.

Results: The one-tailed paired student’s t test with Bon-ferroni correction was used to analyse the data. Only in deep flexion 2PLC reconstruction was significantly better than the 1PLC reconstruction in restoring the posterior laxity to PCL deficient condition (p=0.02). (Figure1) In deep flexion 1PLC could not restore the rotational laxity to PCL deficient condition (p=0.02). In mid flexion the 2PLC was unable to restore the rotational laxity to PCL deficient condition (p=0.048) (Figure 2).

Conclusion: The 2PLC reconstruction was better than the 1PCL in controlling the posterior drawer. The 1PLC technique though not significant tended to over constrain the external & varus rotations.

The aim of this longitudinal study is to compare the clinical outcomes of endoscopic ACL reconstruction with either a 4-strand HT or PT autograft over a 5-year period.

90 patients with isolated ACL rupture received PT autograft and 90 received HT autograft were studied annually for 5 years. Assessment included the IKDC Knee Ligament Evaluation, KT1000, Lysholm Knee Score, thigh atrophy, kneeling pain, hamstring pain and radiographs.

The median Lysholm Knee Score was 96 for the PT group and 95 for the HT group. No significant difference was found for subjective knee function, overall IKDC assessment, Xray findings, manual ligament KT1000 instrumented testing, graft rupture or contralateral ACL rupture. There was an increasing incidence of fixed flex-ion deformity seen in the PT group. There was no difference in the requirement for subsequent surgery. The incidence of kneeling pain at 5 years was significantly higher in the PT group.

Endoscopic reconstruction of the ACL utilizing either autograft can restore knee stability and is menisco protective despite a high level of sporting activity. We did find a worrying trend towards an increasing incidence of fixed flexion deformity with time in the patellar tendon group. Kneeling pain also remains a persistent problem in this subgroup.

Aim: To compare, in a longitudinal study, the clinical outcomes of endoscopic anterior cruciate ligament (ACL) reconstruction with either a four-strand hamstring tendon (HT) or a patellar tendon (PT) autograft over a five-year period, when a similar operative procedure is followed for both groups.

Method: Ninety patients with isolated ACL ruptures who had received PT autografts and another 90 who had received HT autografts were studied annually for five years. Fifty patients were randomised as a subgroup. The assessments included the IKDC Knee Ligament Evaluation, KT1000, Lysholm Knee Score, thigh atrophy, kneeling pain, hamstring pain and radiographs.

Results: The median Lysholm Knee Score was 96 for the PT group and 95 for the HT group. No significant difference was found for subjective knee function, overall IKDC assessment, X-ray findings, manual ligament KT1000 instrumented testing, graft rupture or contra-lateral ACL rupture. There was an increasing incidence of fixed flexion deformity seen in the PT group. There was no difference in the requirement for subsequent surgery. The incidence of kneeling pain at five years was significantly higher in the PT group. The results of the randomised patients were identical to the sequential patients.

Conclusions: Endoscopic reconstruction of the ACL utilizing either type of autograft restored knee stability and was protective of the meniscus despite a high level of sporting activity. We found a worrying trend towards an increasing incidence of fixed flexion deformity with time in the PT group. Pain when kneeling also remained a persistent problem in this subgroup. PT grafts appeared tighter clinically and, with the KT 1000, when assessed up to three years post operatively, compared with HT grafts. Thereafter the results were similar.

Aim: To study the influence of anterior cruciate ligament (ACL) deficiency upon functional outcome after Coventry high tibial osteotomy, four to seven years after the surgery.

Method: One hundred and thirty-five patients (142 knees) each underwent a Coventry high-tibial osteotomy with staple fixation, performed by a single surgeon for medial arthrosis of the knee. During the study period, six patients (seven knees) proceeded to total knee arthroplasty and three patients died from unrelated causes. Nine patients were lost to follow-up. Comparisons were drawn between those patients with an intact ACL (ACLi) and those with ACL deficiency (ACLd).

Results: One hundred and seventeen patients (122 procedures) were available for review (100 males, median age 49 years, range: 29years to 70 years). The median follow up period was 64 months (range 37 to 80 months). The ACLd group was significantly younger (median age was 44 versus 51, p< 0.05) and reported significantly less pain and difficulty with stairs, shopping and rising to stand than the ACLi group. Seventy-eight percent of ACLd patients underwent previous surgical procedures on the affected knee. Ninety-six percent of the ACLd group and 89% of the ACLi group were either enthusiastic or satisfied with the outcome of the surgery. The mean Knee Society Score was 83 and 79 (respectively). All six revisions of the knee arthroplasties were in the ACLi group.

Conclusions: High tibial osteotomy was performed at a younger age for those patients with an absent anterior cruciate ligament. These patients had a subjectively better functional medium-term outcome, despite having had a greater number of surgical procedures prior to the osteotomy and having an ACL-deficient joint.