Increasing knee flexion following total knee arthroplasty (TKA) has become an important outcome measure. Surgical technique is one factor that can influence knee motion. In this study, it was hypothesised that stripping of the posterior knee capsule could improve flexion and range of motion (ROM) following TKA. Patients who were undergoing TKA were prospectively randomised into two groups - one group (62 patients) were allocated stripping of the posterior knee capsule (PCS), the other group (66 patients) no stripping (no-PCS). The primary outcome was change in flexion and ROM compared to pre-operative measurements at three time points; after wound closure, 3months and 1year post-operatively. Secondary outcomes were absolute measurements of flexion, extension, ROM and complications. All operations were performed by a single surgeon using the same implant and technique. All patients received identical post-operative rehabilitation. There was a significant gain in flexion after wound closure in the PCS group (p=0.022), however there was no significant difference at 3months or 1year post-operatively. Absolute values of extension (p=0.008) and flexion (p=0.001) 3months post-operatively were significantly reduced for the PCS group. The absolute value of ROM was significantly higher for the no-PCS group at 3months (p=0.0002) and 1year (p=0.005). There were no significant difference in the rate of complications. Posterior capsular stripping causes a transient increase in flexion that does not persist post-operatively. We do not recommend routine stripping of the posterior knee capsule in patients undergoing TKA.

Introduction: Digital X-rays have become increasingly prevalent in Hospitals throughout the UK and Ireland in the past 10 years. We have devised a semi quantitative analysis of digital radiographs that measures the extent of healing across the fracture gap.

Methods: 48 CD 1 mice underwent a femoral fracture and subsequent fixation with an external fixator. A standardised radiograph was taken. A radiographic analysis was carried out. For each radiograph taken a pixel density graph was generated at five individual points across the fracture gap, along the longitudinal axis of the femur.

A stastical analysis of intra and inter-observer variability was tested using the linearly-weighted kappa statistic for each of the 240 pixel density graphs taken and for the summation total in the 48 radiographs.

Results: For the individual pixel density graphs we expected an agreement of 67.82%. An agreement of 95.42% was recorded showing a kappa statistic of 0.8576 and a standard error of 0.0531.

On analysis of the summation scores we expected an agreement of 75.54% and observed an actual agreement of 96.30%. This showed a kappa statistic of 0.8545 and a standard error of 0.0849.

Conclusion: The results are very similar in the two analyses and indicate excellent agreements. As a result we offer a radiographic, semi-quantative analysis of bone healing across a fracture gap that is highly reproducible. Thus it has the potential for application to future research in this field and possibly to clinical practice with the increased use of digital radiographs in hospital departments

Introduction: Range of motion (ROM) is an important measure of the success of knee Arthroplasty. The extent to which pain relief contributes to improvements in knee ROM in total knee Arthroplasty (TKA) patients is unknown. This prospective study assessed the separate effects of pain abolition and surgery on ROM in a group of 141-osteoathritic patient’s undergoing TKA. Pain had a significant inhibitory effect on knee ROM. Improvements in ROM following TKA may be primarily due to pain relief.

Methods: 141 randomly selected patients underwent LCS total knee arthroplasty (De Puy). A single surgeon performed all operations, using an identical surgical technique. Passive flexion and extension were measured when awake, under anaesthesia, and post-operatively under anaesthesia.

Paired t-tests were used to test for significant differences between the measurements. Independent samples t-tests were used to test for significant differences between the changes in flexion, extension and ROM between the time points tested.

Results:

When awake the mean flexion was 116.8°, extension 3.8°, and ROM 113.0°

Knee flexion (p < 0.0001) and range of motion (p < 0.0001) were significantly greater and knee extension (p < 0.0001) was significantly reduced following anaesthesia only. A further significant increase in knee flexion (p < 0.0001) and range of motion (p = 0.00014) was observed post –operatively under anaesthetic. However knee extension did not significantly increase further (p = 0.29). The average improvement in range of motion once anaesthetised was 16.4° (SD = 13.1°) with the majority of this improvement due to an increase of flexion (average increase of 13.4° (SD = 11.9°) rather than an increase in extension (average increase of 3.0° (SD = 4.2°).

The combined effect of surgery and anaesthetic was 20.5° (SD = 12.3°), with the majority of this improvement due to an increase of flexion (average increase of 17° (SD = 8.5°) rather than an increase in extension (average increase of 3.6° (SD = 6.0°).

Discussion: Pain abolition resulted in a mean increase of 16.4° in the range of motion, and both TKA combined with pain abolition further increased significantly the range of motion to a mean of 20.5°. This study suggests that improvements in ROM following total knee arthroplasty are primarily due to reduction in the symptoms of pain and that other factors such as surgical technique and prosthesis design can further increase ROM.

Future studies should record the measurements of passive flexion, extension and range of motion in the anaesthetised patient, as this will allow objective assessment of changes in range of movement.

Introduction: Revision Hip Surgery presents an increasing Orthopaedic Burden. Indications for revision include recurrent hip dislocation, infection, peri-prosthetic fracture, failure of implants, including aseptic loosening, osteolysis, wear or mechanical failure of components.

Within the region of Northern Ireland, we have investigated the indications for revision hip procedures, carried out from April 2006 to March 2007. We wanted to establish if the indications of revision surgery are comparable to other national registers.

Methods: An audit of all hospitals, which carry out hip revision surgery, was carried out, to identify patients who have undergone revision total hip surgery. The indications for revision procedures were identified, from hospital databases, patient records and examination of pre-operative X-rays. Revision procedures included replacement of one or both components, application of Posterior Lip Augmentation Devices and cable plating or component revision for peri-prosthetic fractures.

Results: 180 patients, who had undergone revision, were identified in six hospitals. 56 were female and 124 were male. Revisions were performed for a peri-prosthetic fracture in 38 (21%), infection in 12 (7%), recurrent dislocation in 23(13%) and failure of implants in 105 (58%). In 2 patients (1%) revision was performed after the development of avascular necrosis following resurfacing hip replacement.

Discussion: The largest body of information on revision hip surgery is the Swedish registry. Their incidence for revision hip surgery is 7%. Their indications were: aseptic loosening 71%, Infection 7.5%, Fracture as 5.6% and dislocation as 4.8%. Our data indicate a greater prevalence of revision for recurrent dislocation and peri-prosthetic fractures than the Swedish data. Further work should aim to identify any remediable surgical factors which account for these differences.

Thrombin related peptide (TP 508) is a 23 amino-acid synthetic peptide that mimics a portion of the receptor-binding domain of the human thrombin molecule.

Thrombin triggers both proteolytic activated receptors and non proteolytic activated receptors to bring about a mixture of responses ranging from tissue breakdown and clot formation, to new vessel formation and tissue repair. TP 508 stimulates only the non proteolytic activated receptors, and this initiates repair and angiogenesis but not clot formation or tissue breakdown Previous studies have shown that TP508 can stimulate repair in the dermal and musculoskeletal tissues by promoting angiogenesis and enhancing the proliferation and migration of cells.

High energy fractures are associated with a delay in healing. We hypothesized that high energy fracture healing would be improved with the use of TP508, and that the dose and site of application would have importance.

Methods: 80 CD 1 Mice were randomised into four groups; all underwent a high energy quadriceps muscle crush and a femoral fracture on the left hind limb. In each case the fracture was reduced and held with an external fixator. At the time of operation Group I received a dose of 100ìg TP 508 into the fracture, Group II 100ìg into the surrounding damaged soft tissue, Group III a dose of 10ìg into the fracture, and group IV (the control group) received PBS carrier into the fracture.

24 animals were sacrificed on day 21 and the remaining 56 mice on day 35. Of the 35 day old animals 8 in each group had both femora harvested and the biomechanical properties were tested using the 3-point bending technique. Specimens from the 21 day old animals and remaining 35 day old animals were used for histological analysis.

All 80 animals had digital radiographs taken each week. Using image analysis software five pixel density graphs were generated across each fracture gap. A validated semi quantitative analysis was used to score each graph and the total accumulated for each radiograph. The width of the fracture calus was measured and expressed as a ratio of the femur diameter.

Results: Mechanical testing showed significantly greater stiffness in group I when compared to control (p < 0.05), and a dose dependent trend of increasing strength.

Radiographic analysis showed greater healing of fracture and callus formation in Group I compared to Groups II, III, and IV, at both three and five weeks post-fracture (P< 0.05).

Histological analysis showed an increase in bone formation in group I compared to the other groups.

Conclusion: This data from this model, suggests that TP508 enhances healing in high energy fractures. The results also suggest that the effects of TP508 are dose dependant, and are greater when delivered into the fracture site.

Purpose: The study objective was to measure ‘posterior condylar offset’ (PCO), and tibial slope (TS) following cruciate-sacrificing total knee arthroplasty (TKA), and determine any influence on one-year flexion values following cruciate-sacrificing Total Knee Arthroplasty.

The term ‘posterior condylar offset’ (PCO) is defined as the distance from a line projected along the posterior cortex of the femur to the maximum convexity of the posterior condyles. Its magnitude has been found to correlate with final flexion following PCL-retaining TKA, if reduced by more than 3mm post-operatively. (1)

Tibial slope is the angle between a line drawn parallel to the articular surface and a line drawn perpendicular to the long axis of the tibia on a lateral radiograph. Increasing the tibial slope in PCL-retaining TKA has been shown to improve maximal flexion of an average 1.7 degrees flexion for every extra degree on the tibial slope. (2)

Method: We reviewed the pre and post-operative radiographs of 69 patients who had undergone cruciate-sacrificing TKA. All cases were performed by a single surgeon using the same operative technique. Preoperative and postoperative true lateral radiographs were used to measure the change in PCO and the TS. Pre-operative and one-year flexion was measured using a goniometer.

Results: There were 26 males and 43 females. Mean age was 68 years (range 38 – 87). 67 of the patients had a primary diagnosis of OA, the remaining 2 patients RA.

The mean pre-operative PCO was 25.9 mm (21 – 35), whilst the mean post-operative PCO was 26.9 mm (21 – 34). The difference in preoperative and postoperative PCO ranged from −6 mm to + 5 mm (average, +1mm).

Three patients 4% had more than 3mm reduction in their PCO following TKA (range −4mm to −6mm). 16% had their post-operative PCO increased by more than 3mm (range 4mm – 5mm). The remaining 80% had their PCO restored to within 3mm either way.

The mean post operative tibial slope was 6.6° with a range of 5–9°, 38% measuring 6°, 21% at 7°, 17% at 8°and 5° and the remaining 7% at 9°.

Of the three patients whose PCO was reduced by more than 3mm, one had the same flexion 1 year postoperatively, one had an increase of 14 degrees, and unfortunately the third died before their 1 year review.

Using regression analysis, the strongest predictor of one-year flexion for this study group was the preoperative flexion value. The change in PCO and angle of the tibial slope had no significant influence on one-year flexion.

Conclusion: It would appear that the LCS technique permits satisfactory restoration of PCO and consistent tibial slope as only 4% of patients in this study had a decrease in PCO of more than 3mm and the range of tibial slope was within 5°. We feel these parameters are important however in this study it did not have significant influence on final flexion.

Purpose: The study objective was to measure ‘posterior condylar offset’ (PCO) following Low Contact Stress (LCS) total knee arthroplasty (TKA), and determine its influence on one-year flexion values.

The term ‘posterior condylar offset’ (PCO) is defined as the distance from a line projected along the posterior cortex of the femur to the maximum convexity of the posterior condyles. Furthermore its magnitude has been found to correlate with final flexion following PCL-retaining TKA, if reduced by more than 3mm post-operatively1..

Method: We reviewed the pre and post-operative radiographs of 69 patients who had undergone primary LCS TKA. All cases were performed by a single surgeon using the same operative technique. The PCO was measured from the preoperative and postoperative true lateral radiographs. Pre-operative and one-year flexion was measured using a goniometer.

Results: Of the 69 patients studied, three patients (4%) had more than 3mm reduction in their PCO following TKA (range −4mm to −6mm). Eleven (16%) had their post-operative PCO increased by more than 3mm (range 4mm – 5mm). The remaining fifty five (80%) had their PCO restored to within 3mm either way.

Of the three patients whose PCO was reduced by more than 3mm, one had exactly the same flexion 1 year post-operatively, one had an increase of 14 degrees, and unfortunately the third died before their 1 year review.

Using regression analysis, the strongest predictor of one-year flexion for this study group was the preoperative flexion value. The difference in PCO before and after TKA had no significant influence on one-year flexion.

Conclusion: It would appear that the LCS technique permits satisfactory restoration of PCO as only 4% of patients in this study had a decrease in PCO of more than 3mm. We feel restoration of PCO is important; however in this study it did not have significant influence on final flexion.

We report a series of 668 patients (699 hips) with an average follow up of 10.5 years (range, 10–11 years) following THR using a cemented custom-made titanium femoral stem and a cemented high-density polyethyl-ene acetabular component. The fate of every implant is known.

The mean age at operation was 68 years (24 – 94 years). The indication for THR was as follows: primary OA (629), RA (18), AVN (10), intracapsular femoral neck fracture (5), Perthes disease (3), developmental hip dysplasia (2) and SUFE (1). The mean pre-operative Harris Hip Score was 19 (range 10 – 42).

One hundred and seventy-four patients (26%) were deceased at the time of their 10-year review. Four hundred and ninety-four patients were subsequently reviewed of which 88 patients (13%) were assessed by telephone review as they were too frail to attend.

The average 10-year Harris Hip Score was 92 (range 43 – 100). The average 10-year Oxford Hip Score was 19 (range 12 – 46). 99.2% reviewed at 10 years stated that they were satisfied with their THR.

Revision surgery occurred in 21 cases (3%). Seventeen femoral components were revised for infection, one for recurrent dislocation and one was iatrogenically loosened during socket revision. There were no cases of revision for aseptic loosening of the stem. Dislocation occurred in 18 cases, of which 4 became recurrent (0.6%). Six patients had a postoperative sciatic nerve palsy (0.9%) with 4 making a full recovery. There was one case of femoral nerve palsy. Eleven patients developed a DVT (1.6%). Six patients had a PE (0.9%) all of which were non-fatal. There were 16 deep and 3 superficial wound infections. Thirty-eight patients had symptomatic trochanteric bursitis post-surgery.

In conclusion, the 10-years results of the custom femoral stem are encouraging with an overall high level of patient satisfaction.