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.