Summary

The BMP-2 content and bone forming potential of 2 leading allograft products (OsteoAMP® and Osteocel® Plus) was tested across 3 commercially available lots. Surprisingly, there was no BMP-2 content associated with the cells contained within Osteocel® Plus. OsteoAMP® contained greater than 1000 times the overall BMP-2 content than Osteocel® Plus. Correspondingly, Osteocel® Plus did not form new bone at any timepoint in the 12 week in vivo study while OsteoAMP® had increasing new bone formation at each sequential timepoint. Interestingly, the highest cellularity of Osteocel® Plus was just prior to implant at t₀, decreasing at each timepoint, decreasing further at the terminal endpoint of the study at 12 weeks (82% of cells had died or migrated). Conversely, the cellularity of OsteoAMP® increased at each timepoint.

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

Dislocation is one of the most common complications following total hip arthroplasty. The literature suggests a frequency of 1–3% for primary total hip replacement (THR) and 7–10% for revision procedures. No definitive treatment algorithm exists for their management, with some surgeons attempting to constrain hip motion with casting or bracing initially. The evidence for this practice is limited. The purpose of this study was to determine the current practice for managing THR dislocation within our unit, and to determine the effectiveness of abduction bracing.

INTRODUCTION

Intramedullary nail fixation has been used for successful treatment of long bone fracture such as humerus, tibia and femur. We look at the experience of our trauma unit in treating long bone fracture using the AO approved Expert femoral/tibial nail and proximal femoral nail antirotation (PFNA). We look at the union and complication rates in patients treated with AO approved nailing system for pertrochanteric, femoral and tibial shaft fracture.

The treatment of patients with arthritis of the glenohumeral joint with an associated massive irreparable cuff tear is challenging. Since these patients usually have proximal migration of the humerus, the CTA extended head allows a surface with a low coefficient of friction to articulate with the acromion.

Between 2001 and 2006 a total of 48 patients with arthritis of the shoulder joint associated with a massive cuff tear, were treated with a CTA head. The indications for use being Seebauer Type 1a and 1b appearances on x-ray and active abduction of the arm to more than 60° with appropriate analgesia. Preoperatively, a Constant score and an ASES pain and function score were completed as well as standard radiological assessment. These were repeated at follow up. Paired t tests were carried out for all the variables. A Kaplan-Meier survival analysis was performed.

Follow up varied between 2 and 8 years. Improvements in pain, function and all movement parameters were significant at p< 0.001. There was no change in the strength component. Survival analysis showed 94% survival at 8 years (95% CL 8%) there were 2 revisions and 5 deaths. Radiological assessment at follow up revealed no evidence of humeral stem loosening. In 5 (17%) cases however there was evidence of erosion in the surface of the acromion and in 13 (45%) erosion of the glenoid. Finally one component was also seen to have subluxed anteriorly.

This head design has been in use for a number of years. To date there appears to be no reported outcome of their use. This series shows that in an appropriately selected patient a satisfactory clinical outcome can be maintained in the short to medium term. The presence of erosion of the glenoid but also the under surface of the acromion does require continuing monitoring.

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.

This multicentre audit assessed the total Tip Apex Distance (TAD) of sliding hip screws for intertrochanteric hip fractures in the 3 fracture hospitals in Northern Ireland (Ulster Hospital, Royal Victoria Hospital & Altnagelvin Hospital). Patient demographics and anaesthetic information was also reviewed. A sample of 140 patients with adequate screening films (39 UHD, 50 RVH & 51 Altnagelvin) were selected. The TAD was measured on AP & lateral screening films and compared to the standard of 25mm or less (total in 2 views) as recommended by Baumgaertner et al (JBJS (Am) 1995).

All 3 hospitals had an average of under 25mm (22.1, 19.9 & 19.6mm respectively) with overall average of 20.4mm, and a TAD of 25mm or less was achieved in 66.7%, 82% & 80.4% in respective hospitals (77.1% of patients overall). No patients were readmitted due to cut-out, despite 22.9% of patients having a TAD greater than 25mm. Among patients with TAD over 25mm the average TAD was 30.1mm

Demographics showed a 77.8% of patients to be female, with a slight predominance of left sided injuries. Most patients were of ASA grading 2–3. Anaesthetic method preferences varied between hospitals. Patients with TAD over 25mm were not significantly different from those with TAD of 25mm or less in age, gender, ASA or operated side.

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.

Objective: To determine if a standard course of outpatient physiotherapy improves the range of knee motion following primary total knee arthroplasty.

Design: One hundred and fifty patients undergoing primary total knee arthroplasty were recruited and randomly assigned into two groups. Group 1 received a course of physiotherapy with a standard protocol over a six week period within 4 weeks of hospital discharge. Group 2 received no outpatient physiotherapy. All patients received inpatient physiotherapy for the length of their hospital stay. Range of knee motion was measured using a goniometer by members of the outcome team blinded to the randomisation. Validated knee scores (Oxford knee and Bartlet patellar) were collected. An SF12 health questionnaire was used as a generic outcome measure.

Results: Both groups were equally matched by age and sex. Although patients in Group 1 achieved greater range of knee motion than those in Group 2 this was not statistically significant. No difference was also noted in any of the outcome measures used.

Conclusion: We conclude that in patients undergoing primary total knee arthroplasty, inpatient physiotherapy with good instructions and a well-structured home exercise regime can dispense with the need for outpatient physiotherapy.

Isolated patellofemoral osteoarthritis has been reported to occur in approximately 5% of patients with gon-arthrosis of the knee. A number of options are available for the surgical management of these individuals. We reported the short-term outcomes on thirty three patients (33 knees) with isolated patellofemoral osteoarthritis who underwent LCS total knee arthroplasty (TKA) without resurfacing who had been operated on between 1996 – 1999¹.

Barrack et al² in 2001 reported on the incidence of anterior knee pain in two groups of TKA patients, one with patella resurfacing and one without. They reported an increase incidence of anterior knee pain in both groups.

We now report the longer-term outcomes with an average follow-up of 80.2months (range 54–94 months). At latest review, 9 patients experienced night time pain, all describing it as improved from their preoperative level. Twelve patients walked with the use of a walking aid, compared with 21 preoperatively. Disease specific scores at latest review showed improved outcome measures at latest review.

We also report our outcomes in an additional fifty-five patients (59 knees) with isolated patellofemoral osteoarthritis who were treated between 1999–2004 receiving an LCS total knee arthroplasty without patellar resurfacing. Our preliminary findings suggest that this technique continues to be an option in the management of the older patient with isolated patellofemoral osteoarthritis.

Introduction: The purpose of this study was to quantify changes in lower limb muscle strength in children with spastic diplegic cerebral palsy 6 months after multi-level orthopaedic surgery.

Method: A consecutive sample of 20 children ( 10 girls and 10 boys, mean age 10.6) with spastic diplegia was studied prospectively. All participants had soft-tissue and bony surgical procedures performed as part of their clinical management. Physiotherapy treatment commenced following surgery. Lower limb muscle strength, pre and 6 months post-surgery, was measured, in addition to routine gait and function assessment. Maximum voluntary isometric strength of 5 muscle groups was measured bilaterally using a digital dynamometer. Paired-samples t-tests were performed.

Results: There was a marked deterioration of muscle strength (p < 0.05) in all muscle groups. Medial hamstrings and hip flexors showed the greatest decline with an average decrease of 54% and 41% respectively. Analysis of gait parameters showed a significant improvement in kinematics (p< 0.05) but a decrease in walking velocity and cadence. Motor function decreased significantly (p< 0.05). There was reduced motor power in 18 of the 20 at 6 months.

Discussion: Our results quantified objectively the magnitude of strength changes after multi-level surgery and show that weakness may be greater and persist longer than expected. This information will be useful for planning treatment after multi-level surgery and is part of a randomised trial investigating strength training. In general there is a decrease in power but an improvement in gait.

Introduction Range of motion (ROM) is an important measure of outcome. A better understanding of the factors influencing ROM is important when counselling patients undergoing TKA.

Aim The aim of the study was to prospectively evaluate the influence of a number of selected variables on knee flexion at one year using the same prosthesis in a single surgeon series.

Patients and Methods 170 patients (57 males; 113 females) undergoing TKA were prospectively evaluated. The following data was recorded for each patient: age, gender, primary diagnosis, direction and magnitude of the preoperative axial deformity, BMI, cement use, preoperative and one year Oxford Knee Scores (OKS), the active and passive range of motion (ROM) preoperatively, at the end of surgery and at three month and one year review.

Results Average flexion values at each stage were as follows: preoperative (1110), end of surgery (1200), three months (1030) and one year (1070). There was a significant loss of flexion following TKA. The improvement between three months and one year however proved significant. Multiple regression analysis revealed that preoperative flexion was the strongest predictor of one-year flexion. Increasing age was also found to have a significant influence on final flexion. Gender, BMI, pre-operative OKS and cement use had no significant influence on final flexion. Patients tend to migrate towards a middle range of flexion i.e. those with poor flexion gain movement whilst those with good flexion tend to lose motion.

Conclusions Preoperative flexion is the strongest predictor of final flexion following TKA.

Introduction Fixed flexion deformity (FFD) represents a challenge during total knee arthroplasty (TKA). Furthermore, controversy exists as to the fate of FFD following TKA.

Aims The aims of this study were to determine how fixed flexion behaves in relation to surgery, factors that may influence or correlate with FFD both preoperatively and following TKA and the effect of FFD on outcome at one year.

Patients and Methods 133 patients (41 males; 92 females) undergoing TKA were prospectively studied. The following data was recorded for each patient: age, gender, primary diagnosis, direction and magnitude of the pre-operative axial deformity, BMI, preoperative and one year Oxford Knee Scores (OKS), the active and passive range of motion (ROM) preoperatively, at the end of surgery and at three month and one year review. FFD was defined as forced passive extension (FPE) greater than zero degrees.

Results Sixty-six patients (50%) had a preoperative FFD (mean, 60). At the end of surgery, this measured 10, 80 at 3 months and 40 at one year. When comparing those with a preoperative FFD to those with no FFD, there was no significant difference when assessing age, BMI or preoperative OKS. Preoperative FFD was significantly more common in males although there was no significant difference in the magnitude of FFD at any stage between males and females. There was a significant improvement in FFD at one year. Patients with a preoperative FFD were found to have significantly less flexion both preoperatively and at one year. When comparing those with FFD at one year to those with no FFD, those with FFD were significantly older and had significantly less flexion. There was no significant difference in BMI, OKS or gender.

Conclusions There is a definite trend when assessing the change in FFD with time. Correction at the time of surgery would appear to be important. Residual FFD is associated with reduced flexion at one year.

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.

Introduction Satisfactory patellar tracking is important following total knee arthroplasty. A lateral retinacular release may be required to correct patellar maltracking but can be complicated by damage to the skin, soft tissues or patella.

Aim The aim of this study was to determine if, when using the LCS prosthesis, the rate of lateral patellar release was reduced by centering the finishing guide on Whiteside’s line as opposed to the mid-point of the femoral condyles.

Patients and Methods One hundred and ten consecutive patients (64 female, 46 male) undergoing primary total knee arthroplasty were prospectively studied. At the time of performing the champher cuts, the finishing guide was first centered on the mid-point of the femoral condyles and a mark placed on the trochlea using the needle diathermy. The finishing guide was then finally centered on the previously marked Whiteside’s line. The distance between the two marks was measured using a caliper. Following component insertion patellar tracking was checked. If required a lateral release was performed allowing the patella to track with its medial facet in contact with the medial femoral condyle.

Results Centralization of the femoral component on Whiteside’s line instead of the mid-point of the femoral condyles lateralized the component by an average of 2.7mm (range, x–ymm). This parameter was termed the patellofemoral offset (PFO). When compared to a sample of patients where the finishing guide was centered on the mid-point of the femoral condyles, the lateral patellar release rate was reduced from 25% to 18%.

The magnitude of PFO increased with age however there was no significant difference in PFO between males and females. The PFO was significantly greater for knees with a preoperative valgus deformity (p=0.006).

Conclusion Centering the femoral component on White-side’s line leads to a reduction in lateral patellar release rate during TKA.

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.

The Austin Moore Prosthesis (AMP) is a recognised treatment option in the management of displaced intracapsular femoral neck fractures in elderly patients. Peri-prosthetic femoral fractures are a potential complication of both cementless and cemented hemiarthroplasty and can occur intra-operatively or at any stage following implant insertion.

Over a two-year period, 244 patients underwent hemiarthroplasty for a displaced intracapsular femoral neck fracture. Seventy patients had an AMP inserted whilst 174 patients were treated using a cemented Thompson stem. All of the AMP’s were inserted by, or under the supervision of an orthopaedic consultant.

Five patients (7%) from the AMP group sustained a periprosthetic femoral fracture. Four required revision surgery. The remaining case was managed non-operatively.

When compared to the cemented Thompson hemiarthroplasties performed over the same time period, despite the operating time being significantly less, the number of periprosthetic femoral fractures was significantly greater with the AMP. Furthermore, the early mortality rate was significantly higher for the AMP group who, were also significantly older and more likely to require postoperative blood transfusion. There was no significant difference in gender or ASA grade between the two groups.

These findings suggest that for displaced intracapsular femoral neck fractures in elderly patients, when hemiarthroplasty is the treatment of choice, a cemented prosthesis is preferable.

We report the result of 46 patients (30 female, 16 male) with periprosthetic femoral fractures who underwent insertion of the Kent Hip Prosthesis. Average age was 73 years (range 43–96years) and follow-up ranged from one to seven years (average, 4 years). The primary implants involved were as follows: Charnley (26), Austin Moore (6), Howse (5), Custom (4), Exeter (1), DHS (1), Thompson (1) and Richards (1). Average time to fracture from insertion of the primary implant ranged from 3 weeks to 20 years (average, 8 years). Forty cases were post-primary implant fractures (38 traumatic, 2 atraumatic) and 6 occurred intraoperatively. Using the Johanssen classification there were 12 type I, 30 type II and two type III fractures. Of the 46 cases, prior to fracture, 42 were living in their own home, 24 were mobile unaided and 20 had thigh and/or groin pain. Thirty-two had a loose stem and/or cup assessed at the time of surgery. Operating time was on average 143 mins (65–235mins). At latest follow-up, 43 were living in their own home, 5 were walking unaided and 10 had ongoing pain. In 34 cases complete union was achieved. There were no cases on non-union. Three patients required revision surgery for broken stems. Three patients sustained wound infections and there were six posterior dislocations. All of the complications were treated satisfactorily. We conclude that the Kent Hip Prosthesis is a useful option in the management of periprosthetic femoral fractures.

Leg-length inequality is not uncommon following primary total hip arthroplasty and can be distressing to the patient. An excellent clinical result with respect to pain relief, function, component fixation, range of motion and radiographic appearance can be transformed into a surgical failure because of patient dissatisfaction due to leg-length inequality.

Postoperative leg-length discrepancy was determined radiographically for 200 patients who had had a primary custom total hip arthroplasty. In all cases the opposite hip was considered to have a normal joint center.

The femoral component was designed and manufactured individually for each patient using screened marker x-rays. A graduated calliper was used at the time of surgery to control depth of femoral component insertion. The transverse acetabular ligament was used to control placement of the acetabular component and therefore restore acetabular joint center.

Using this method 94% of subjects had a postoperative leg-length discrepancy that was 6mm or less when compared to the normal side (average, +0.38mm). The maximum value measured for leg-length discrepancy was +/−8mm.

We describe a simple technique for controlling leg length during primary total hip arthroplasty and propose an alternative radiographic method for measuring leg-length discrepancy.

Introduction: Traditionally, the degree of correction for derotational femoral osteotomies in cerebral palsy has been based on clinical or radiographic measures. Recently, three dimensional gait analysis has been used to plan and evaluate orthopaedic surgery. Our aim was to assess the outcome of derotation osteotomies, where the degree of rotation at surgery was guided by transverse plane kinematics (aiming at reducing peak hip rotations to normal limits).

Method: Pre and post-operative gait analyses were reviewed in a group of these patients (16 legs) and compared with a similar group of 8 patients (16 legs) who had soft tissue procedures only.

Results: Improvement following derotation osteotomy occurred in all but one case; 11/16 osteotomies resulted in peak internal rotation within one standard deviation (SD) of peak normal internal rotation (normal range −6° to +11°), the other 4 were within 1.4 SDs.

Discussion: Objective improvement in hip rotation during gait was measured in 15/16 subjects undergoing dero-tation osteotomy based on gait analysis. There was no rotational change overall in patients who had soft tissue procedures only. Average dynamic correction of internal rotation during gait was slightly less than intra-operative correction, possibly due to tensioning of spastic muscles.