Objectives

Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE).

Objectives

To evaluate the neck strength of school-aged rugby players, and to define the relationship with proxy physical measures with a view to predicting neck strength.

Introduction: Traumatic knee dislocations are rare but devastating injuries. We have evaluated the clinical results of ligament repair and reconstruction. Knee dislocation was defined as an acute event that produced multidirectional instability with at least 2 of the 4 major ligaments disrupted.

Materials: Twenty-one patients with 22 knee dislocations presented between 1994 and 2001. There was one vascular and one common peroneal nerve injury. Eight (38%) patients were treated in the acute period (< 14 days), 5 (24%) had reconstructions within 1 year of injury. The remainder were late reconstructions. The patients were evaluated at mean follow-up of 32 months (11 to 77). This included ROM measurement, clinical and instrumented ligament laxity testing. Posterior stress view with 10kg weight was used to evaluate the PCL reconstruction. Function was evaluated using the IKDC chart, the Lysholm Score, the Tegner Activity Level, the Knee Outcome Survey and WOMAC.

Results: The mean extension deficit was 6.8 degrees (0–25) and mean flexion deficit was 8.6 degrees (0–20). Of the ACL reconstructions, 4 knees had 0–3mm side-to-side difference, 15 knees had 3–5mm and 1 knee had 6–10mm. Of the PCL reconstructions, 2 were within 3–5mm of side-to-side difference, 9 knees were 6–10mm and 4 were more than 10mm. Posterolateral corner repair/reconstructions appeared durable. None of the knees were IKDC Grade A, 8 knees were Grade B, 9 were as Grade C and 5 were Grade D. The mean Lysholm Score was 81 (66–100) and the mean Tegner Activity Level was 4.9 (1–7). The mean Knee Outcome Survey score was 75 (41–99). Acutely treated knees had better scores than late reconstructions.

Conclusion: Our study has demonstrated good function in the operatively treated knee dislocations at 1–7 years. Nearly all had few problems with daily activities. The ability to return to high-demand sports and heavy manual labour was less predictable.

Traumatic knee dislocations are rare but devastating injuries. We have evaluated the clinical results of ligament repair and reconstruction. Knee dislocation was defined as an acute event that produced multidirectional instability with at least 2 of the 4 major ligaments disrupted.

Twenty-one patients with 22 knee dislocations presented between 1994 and 2001. There was one vascular and one common peroneal nerve injury. Eight (38%) patients were treated in the acute period (< 14 days), 5 (24%) had reconstructions within 1 year of injury. The remainder were late reconstructions. The patients were evaluated at mean follow-up of 32 months (11 to 77). This included ROM measurement, clinical and instrumented ligament laxity testing. Posterior stress view with 10kg weight was used to evaluate the PCL reconstruction. Function was evaluated using the IKDC chart, the Lysholm Score, the Tegner Activity Level, the Knee Outcome Survey and WOMAC.

The mean extension deficit was 6.8 degrees (0–25) and mean flexion deficit was 8.6 degrees (0–20). Of the ACL reconstructions, 4 knees had 0–3mm side-to-side difference, 15 knees had 3–5mm and 1 knee had 6–10mm. Of the PCL reconstructions, 2 were within 3–5mm of side-to-side difference, 9 knees were 6-10mm and 4 were more than 10mm. Posterolateral corner repair/reconstructions appeared durable. None of the knees were IKDC Grade A, 8 knees were Grade B, 9 were as Grade C and 5 were Grade D. The mean Lysholm Score was 81 (66–100) and the mean Tegner Activity Level was 4.9 (1–7). The mean Knee Outcome Survey score was 75 (41–99). Acutely treated knees had better scores than late reconstructions.

Our study has demonstrated good function in the operatively treated knee dislocations at 1–7 years. Nearly all had few problems with daily activities. The ability to return to high-demand sports and heavy manual labour was less predictable.

We conducted a prospective, randomised and double blinded study to observe the recovery of knee function in 50 patients undergoing knee replacement with or without patella resurfacing.

Patients were assessed pre-operatively, at four months and a minimum 18 months after surgery using three scoring systems, the Knee Society Clinical Outcome Score, WOMAC and the SF-36 health questionnaire. In addition the active range of knee movement when weight bearing was measured using an electrogoniometer. Patients were asked to undertake 11 standardised activities including level walking, stair climbing and getting into and out of low chairs. Patients were randomised at the time of surgery into receiving a knee replacement with or without patella resurfacing.

Forty-two patients, (18 with patella resurfacing, 24 with no resurfacing) completed assessments at all time intervals. All patients in the study demonstrated an improvement in terms of pain relief and function by four months after knee replacement with a further but less significant improvement by 18 months. The active range of knee movement measured by electrogoniometry recovered to the pre-operative range for all activities but there was no increase in knee movement. Patients who had patella resurfacing had a significantly lower (p < 0.02) score on the Knee Society Clinical Outcome function score at 18 months compared to patients without patella resurfacing. There was no significant difference (p > 0.05) in the active range of knee movement with or without patella resurfacing, although patients with patella resurfacing in general had slightly poorer range of movement particularly for activities that required knee flexion beyond 70 degrees.

We concluded that in this study knee function was not improved by patella resurfacing when compared to a matched group of patients without resurfacing. As patients recovery stabilises by 18 months it appears that the final functional outcome following knee replacement is not enhanced by patella resurfacing.