Aims

Nearly 99,000 total knee arthroplasties (TKAs) are performed in UK annually. Despite plenty of research, the satisfaction rate of this surgery is around 80%. One of the important intraoperative factors affecting the outcome is alignment. The relationship between joint obliquity and functional outcomes is not well understood. Therefore, a study is required to investigate and compare the effects of two types of alignment (mechanical and kinematic) on functional outcomes and range of motion.

Aim: To investigate and compare the effects of two types of LCS total knee arthroplasty on joint proprioception and range of motion.

Methods: 47 patients were randomised to receive either a LCS AP glide or Rotating platform prosthesis. Clinical scores (Oxford knee score, American knee society score, EuroQol), range of motion and proprioception were assessed prior to and at 3,6, and 12 months after the operation. Proprioception was assessed in terms of absolute error angle (mean difference between the target angle and the response angle). Knee angles were measured in degrees using an electromagnetic tracking device, Polhemus 3Space Fastrak that detected positions of sensors placed on the test limb. Student’s t-test was used to compare the mean of two groups (with a level of significance of p < 0.05).

Results: Both groups were comparable in terms of pre-operative range of motion, oxford knee score, American knee society score, EuroQol score and proprioception. There was statistically significant improvement in the Oxford knee score, AKSS and EuroQol score in both groups (p< 0.001), but there was no difference between the groups with respect to these parameters. There was improvement in the proprioception (reduction in absolute error angle) in both groups though this was not significant statistically (p> 0.05).

Conclusions: We did not find significant difference between AP glide and RP LCS knee arthroplasty in terms of improvement in proprioception and range of motion.

Introduction: Reported incidence of dislocation following dislocation of hip replacements varies from less than 1% to 8%, the majority (59%) being in the first 3 months and 77% within a year. Recurrent dislocation of total hip arthroplasty is a serious problem for both patient and surgeon. Revision of the components does not guarantee success and there is significant comorbidity associated with major revision surgery. Early techniques of cup augmentation were complicated by screw and augment failure, hence cup augmentation evolved into a low profile polyethylene wedge with a separate metal backing and five screw fixation called the Posterior Lip Augmentation device (PLAD).

Methods: 33 patients in Leeds and Inverness underwent PLAD placement between 1995 and 2000. They were followed up at a minimum of 5 years postoperatively (5–9 years). Where patients had died the cause of death and status of the PLAD at time of death was determined from the notes.

Results: The mean age at time of PLAD insertion was 73 years(43–94). The longest survival was 102 months, the shortest 8 days. Of the 33 patients undergoing PLAD insertion, 3 were lost to follow up, 13 had died by the time of follow up, 7 had been revised and 10 had survived revision free.

Discussion: When considering the revision as an end point, PLAD insertion compares favourably with total revision. As shown by the mortality of the patients in the cohort, a less invasive option for the patient with significant comorbidities is useful to have in the surgical armamentarium.

Purpose: We report the 10 to 13 year results of the PFC knee system at our institution.

Method/Results: Between 1992 and 1995 97 PFC primary knee arthroplasties were performed consecutively in 82 patients. 32 patients have subsequently died (37 knees) and four (4 knees) are lost to follow-up. Clinical and radiological review of 46 patients (56 knees) was performed at a mean of 11.1 years post-operatively. Outcome was assessed using the Charnley modification of the Merle D’Aubigne score, with a median of 5 for pain and 4 for function. Radiological failure was defined as progressive radiolucency (1 case), lysis (1 case) or subsidence (1 case). Polyethylene wear was detectable in 10 cases, with > 50% in two. There was 100% survivorship with revision for aseptic loosening as an endpoint. There has been one revision for infection and one patella resurfacing, giving a 98% survivorship with no re-operation. In addition one periprosthetic fracture above a well fixed femoral component, required a supracondylar nail.

Conclusions: The PFC gives excellent outcome and survivorship at 13 years, regardless of the experience of the operating surgeon. This demonstrates that with careful training the PFC is a reliable knee replacement in the long-term for trainers and trainees alike.

Aim: To investigate and compare the effects of two types of LCS total knee arthroplasty AP glide {(posterior cruciate is retained and the mobile bearing allows anteroposterior and well as rotational movement) and RP (in which posterior cruciate is sacrificed and the mobile bearing allows only rotational movement)} on joint proprioception and range of motion.

Methods: 30 patients scheduled to undergo mobile bearing total knee arthroplasty were randomised to receive either a LCS AP glide or Rotating platform prosthesis. Clinical scores (Oxford knee score, American knee society score (AKSS), EuroQol), range of motion and proprioception were assessed prior to and at three and six months after the operation. Proprioception was assessed in terms of absolute error angle (mean difference between the target angle and the response angle). Student’s t-test was used to compare the mean of two groups (with a level of significance of p < 0.05).

Results: Both groups were comparable in terms of pre-operative range of motion, oxford knee score, American knee society score, EuroQol score and proprioception. At 6 months there was significant improvement in the Oxford knee score, AKSS and EuroQol score in both groups (p< 0.001), but no difference was noted between the two groups with respect to these parameters. There was improvement in the proprioception (reduction in absolute error angle) in both groups though this was not significant statistically (p> 0.05). The mean active non-weight-bearing range of motion improved in both groups {AP glide group, (p< 0.05) and RP group, (p> 0.05)}

Conclusions: We did not find significant difference between AP glide and RP LCS knee arthroplasty in terms of improvement in proprioception and range of motion.

Objective- To review the 10-year results of 269, cemented total hip arthroplasties performed using matte surface finish Harvard femoral stem that is almost similar to Charnley femoral stem.

Design- Retrospective cross sectional survivorship study.

Patients and Methods- We retrospectively reviewed the results of 269 cemented total hip arthroplasties performed using Harvard femoral stem in 257 patients (M:F, 93:164. Mean age 71.2 years) between 1990–1994. We also reviewed a group of 51 patients who had hip arthroplasty performed on the contralateral side using cemented Charnley femoral stem. Radiographs were reviewed to evaluate following parameters: type of osteoarthritis, cement mantle thickness, alignment of the components, presence of aseptic loosening and radiolucent lines. Kaplan-Meier survival analysis was performed to calculate the survival of Harvard and Charnley femoral stem using various end points. Cox proportional-hazard analysis was performed to evaluate the impact of various radiological parameters on the prosthesis survival.

Results- Out of the 248 eligible patients (260 hips), 6 patients (7 hips) were lost to follow up and 67 patients were dead at the time of the study. 36 hips (35 patients) underwent revision surgery for aseptic failure (Median duration: 60 months, range: 12–125 months) and 11 hips were revised for septic failure (Median duration: 24 months, range: 10–53 months) from the index procedure. Femoral component was revised in all patients whereas acetabular component was revised in 27 patients. 10 year survival for the femoral and acetabular components using aseptic loosening (with and without revision surgery) as an end point was 77.5% (71.5%-83.5%) and 91.1% (87.2%-95%) respectively. Cox regression analysis did not reveal statistically significant (p> 0.05) impact of various radiological parameters on survival rate.

The 10 year survival in the bilateral hip arthroplasty group for the Charnley femoral component (Median follow up 138 months) and Harvard femoral component (Median follow up 120 months) using aseptic loosening as an end point was 95.2% (92.4%-98%) and 77.2% (69.2%-85.2%) respectively.

Conclusion- Our results suggest that the matte surface finish femoral component has less satisfactory long-term survival rate compared to smooth surface femoral stem with similar geometry.

Objective- To evaluate three femoral cement pressurization techniques in a laboratory setting.

Design- Observational study using a plastic femur (sawbone) model.

Materials and Methods- 12 femoral bone models were cemented and pressurized using three different cement pressurization techniques (standard technique, pressuriser in situ technique, and thumb pressurisation technique). Four sets of observations were taken for each technique. Intramedullary pressure readings were obtained using proximal and distal pressure monitoring transducers. The peak pressure and the time for which the pressure was above a particular cut off level (5 KPa and 100 KPa) were compared.

Results- There were significant variations between the peak pressure and the duration for which the pressure was above 100 KPa. The pressuriser in situ technique yielded significantly (p< 0.001) higher peak pressure both proximally (397.5 ± 40.2 KPa) and distally (597.3 ± 102.4). The standard technique produced the optimum pressure of 100 KPa for significantly (p< 0.001) longer duration proximally and distally (66.8 ± 29.5 and 45.2 ± 15.5 seconds respectively) compared to the other two techniques (less than 5 and 17 seconds for thumb pressurisation technique and pressuriser in situ technique respectively, both proximally and distally). There were no significant statistical differences between the three methods for the time for which the cement pressure was higher than 5 KPa.

Conclusion- Although the pressuriser in situ technique produced highest peak pressure, the standard technique produced optimum pressure for longer duration. The standard technique seems to be adequate to achieve optimum pressurization during femoral cementing without increased risk of embolisation.