Background

Previous studies have individually shown extracorporeal shockwave therapy (ESWT) to be beneficial for mid-substance Achilles tendinopathy, insertional Achilles tendinopathy or plantar fasciitis. The purpose of this pragmatic study was to determine the efficacy of ESWT in managing the three main causes of refractory heel pain in our routine clinical practice.

Aim

We aim to compare post-operative length of stay and cardiopulmonary morbidity in patients randomised to either navigated or conventional total knee arthroplasty (TKA).

We aim to compare post-operative length of stay and cardiopulmonary morbidity in patients randomised to either navigated or conventional total knee arthroplasty (TKA).

Patients undergoing primary TKA for osteoarthritis were prospectively assigned randomly to either navigation-guided or control groups and blinded to this.

All patients received a PFC implant (DePuy, Warsaw, IN). In the control group the standard femoral intramedullary and tibial extramedullary alignment rod was used. In the navigation group, the BrainLab (Munich, Germany) navigation system was used. All operations were carried out by one of two consultant orthopaedic knee surgeons.

Length of post operative hospital stay and the development of cardiopulmonary complication were recorded and groups compared.

100 patients were recruited (55 control vs 45 navigated). Patient demographics were similar in both groups.

Mean length of stay was 7 days in the control group (range 3-101), 5 days in the navigation group (range 3-10). The mode was 4 days in both groups.

7 patients (13%) stayed for >7 days in the control group, 3 patients (7%) stayed >7 days in the navigation group(p=0.339).

4 patients(7%) required >10 days inpatient stay in the control group, 0 patients required to stay in hospital for longer than 10 days in the navigation group(p=0.069).

The causes for the length of stay exceeding 10 days were pulmonary embolus in 3 patients, and chest infection in 1 patient.

Patients undergoing navigation-guided TKA required shorter post-operative inpatient stays than those undergoing arthroplasty using conventional techniques. Fewer patients in the navigation group required stays longer than 7 or 10 days. The difference in post-operative stay was associated with fewer respiratory complications in the navigated group.

Sectioned femoral components retrieved from failed hip resurfacing arthroplasties show resorption of proximal femoral bone or formation of a fibrous membrane at the bone cement interface. Our study uses Finite Element Analysis (FEA) to examine the effects of the implant orientation on bone remodelling following hip resurfacing arthroplasty. A radiographic analysis of the proximal femur following hip resurfacing was conducted in order to draw a comparison to the FEA findings.

A 3D FEA model of the Birmingham Hip Resurfacing (BHR) was created based on the geometry and material properties of a 45 year-old female donor hip. Hip joint and muscle loads were applied. Bone remodelling stimuli was determined using changes in strain energy. A range of implant orientations were compared to study the affect on bone remodelling. A retrospective radiological analysis was undertaken on 100 hips with a minimum of 5 years follow up. Femoral neck diameter was measured at post-op, 2 and 5 years, as well as neck and stem shaft angles.

FEA showed that valgus orientation was associated with increased resorption underneath the shell. Varus orientation showed increased bone formation at the stem tip. The radiological analysis identified 2 distinct patterns of neck thinning. Slow thinners (76%) had < 5% reduction in neck diameter at 2 years and < 10% at 5 years. Rapid thinner (24%) had > 5% thinning at 2 years and > 10% at 5 years. The mean percentage reduction in neck diameter was significantly different between the two groups at the two time points (p< 0.01). The rapid group had a higher proportion of valgus aligned implants (88%) and a significant decrease in reconstructed offset (p=0.0023).

The FEA results have shown that stem alignment can affect bone resorption resurfacing. FEA results were consistent with the radiological findings. Additional retrieval studies are necessary to help understand aetiology of implant failures.

We performed a prospective cohort study to investigate the comparability of subjective and objective assessment scores of shoulder function following surgery for rotator cuff pathology.

A consecutive series of 372 patients underwent surgery for rotator cuff disorders with post-operative follow up over 24 months. 248 patients only had subacromial decompression, whereas 124 patients had rotator cuff repair additionally (93 arthroscopic; 31 open). Assessments were made pre-operatively, and at 3, 6, 12, and 24 months post-operatively using the Disabilities of the Arm, Shoulder, and Hand (DASH) score; Oxford Shoulder Questionnaire (OSQ); and the Constant score, which was used as a reference. Standardisation calculations were performed to convert all scores into a 0 to 100 scale, with 100 representing a normal shoulder. The student’s t test was used to compare the mean score for each subjective tool (DASH and OSQ) with the objective score (Constant) at each time point. Pearson’s Correlation coefficient was used to analyse the changes with time post-operatively. The statistical tests were used for the individual surgery types as well as all surgeries collectively. The relationship between the DASH and the Constant score was strongly correlated in all types of surgery.

The relationship between the Oxford and Constant scores was similar, except in the open rotator cuff repair group. There was no statistical difference between the mean DASH and Constant scores for all interventions at any time point. A significant difference was seen between the mean Oxford and Constant scores for at least one time point in all but the open rotator cuff repair group.

We demonstrate that the DASH and Oxford scoring systems would be useful substitutes for the Constant score, eliminating the need for a trained investigator and specialist equipment required to perform the Constant score with the associated cost benefits.

We performed a prospective audit to investigate the comparability of subjective and objective assessment scores of shoulder function following surgery for rotator cuff pathology. A consecutive series of 372 patients underwent surgery for rotator cuff disorders with post-operative follow up over 24 months. 248 patients solely underwent subacromial decompression, whereas 124 had additional rotator cuff repair (93 arthroscopic; 31 open).

Assessments were made pre-operatively, and at 3, 6, 12, and 24 post-operative months using the Disabilities of the Arm, Shoulder, and Hand (DASH) score; Oxford Shoulder Questionnaire (OSQ); and the Constant score, which was used as a reference. Standardisation calculations were performed to convert all scores into a 0 to 100 scale, with 100 representing a normal shoulder. The student’s t-test was used to compare the mean score for each subjective tool (DASH and OSQ) with the objective score (Constant) at each time point. Correlation coefficients (Pearson’s) were used to analyse the changes with time (post-operative course). Each statistical test was used for all surgeries collectively and for the individual surgery types.

The relationship between the DASH and the Constant score was robust in all types of surgery. The relationship between the Oxford and Constant was generally robust, except in the open rotator cuff group. There was no statistical difference between the mean DASH and Constant scores for all interventions at each time point. A significant difference was seen between the mean Oxford and Constant scores for at least one time point in all but the open rotator cuff repair group.

We demonstrate the DASH and Oxford scoring systems would be useful substitutes for the Constant score, obviating the need for the trained investigator and specialist equipment required to perform the Constant score, alongside the associated cost benefits. Further it provides evidence of service, aids appraisal and revalidation.

We describe a new technique for fixing the proximal pole scaphoid fractures both in acute and chronic setting and present our preliminary results.

We prospectively studied fixation of 25 proximal pole scaphoid fractures (1 acute displaced and 24 non unions) with this technique between 1999 and 2007. Mean age of patients was 25 years and mean time to the operation was 6 months.

The technique involves making a transverse dorsal incision over the radius along the radio-carpal junction. The retinaculum is split in line with its fibres. Access to the radio-carpal joint is achieved through the third extensor compartment. The ligament attachment to the scaphoid is preserved by using a modified Mayo approach. A window is created initially at the proximal end of the dorsal ridge. The fracture is reduced and stabilised with an appropriate length Herbert screw. The fracture site is curetted through this window and cancellous bone graft from the distal radius is packed into the fracture site. The capsule and extensor retinaculum is then closed in layers.

Radiological union was achieved in 23 cases, one case required refixation and one case was lost to follow up. Our technique is tendon sparing, capsule retaining, and ensures maintenance of articular surface congruity. So far this technique has led to excellent results.

Adverse bone remodeling in the proximal femur may be detrimental to the long term survival of resurfacing prosthesis. Bone resorption beneath the femoral shell and thinning of the femoral neck have been observed. We present a radiological analysis of the incidence, rate, site of neck thinning and changes observed within the femoral neck, in 100 cases, with a minimum of five years follow-up.

Femoral neck diameter was measured at zero, two and five years post-operatively, at the head neck junction and five mm distally. Pre and post-operative head to neck ratios, natural and reconstructed offset, femoral neck-shaft and stem-shaft angles and cup inclination angle were measured.

Two distinct patterns of neck thinning were observed. In 76 cases (slow thinning group), we observed a reduction of < 5% of original neck diameter at two years and < 10 % at five years (mean 1.5%, sd+/− 1.5). In 24 cases (rapid thinning group), a reduction of > 5% of original neck diameter at two years and > 10% at five years (mean 10.4%, sd+/− 4.8) was observed. The difference in the percentage reduction in neck diameter was significantly different between the two groups at both time points (p< 0.01). Larger head-neck ratios were observed in the rapid thinning group, both pre and post operatively (p< 0.01).

The viability of bone underneath the femoral head may be compromised as a consequence of a non-physiological bone loading mechanism. FEA has predicted stress shielding underneath the femoral head and loading of the mini stem. Compromised blood supply of the retained epiphyseal remnant may play a part in femoral head resorption.

Femoral neck thinning is a phenomenon of unproven aetiology which affects almost 25% of our resurfacing cases.

Introduction: We performed a prospective cohort study to investigate the comparability of subjective and objective assessment scores of shoulder function following surgery for rotator cuff pathology.

Materials and Methods: A consecutive series of 372 patients underwent surgery for rotator cuff disorders with post-operative follow up over 24 months. 248 patients solely underwent subacromial decompression, whereas 124 had additional rotator cuff repair (93 arthroscopic; 31 open). Assessments were made pre-operatively, and at 3, 6, 12, and 24 post-operative months using the Disabilities of the Arm, Shoulder, and Hand (DASH) score; Oxford Shoulder Questionnaire (OSQ); and the Constant score, which was used as a reference. Standardisation calculations were performed to convert all scores into a 0 to 100 scale, with 100 representing a normal shoulder. The student’s t test was used to compare the mean score for each subjective tool (DASH and OSQ) with the objective score (Constant) at each time point. Correlation coefficients (Pearson’s) were used to analyse the changes with time (post-operative course). Each statistical test was used for all surgeries collectively and for the individual surgery types.

Results: The relationship between the DASH and the Constant score was robust in all types of surgery. The relationship between the Oxford and Constant was generally robust, except in the open rotator cuff group. There was no statistical difference between the mean DASH and Constant scores for all interventions at each time point. A significant difference was seen between the mean Oxford and Constant scores for at least one time point in all but the open rotator cuff repair group.

Conclusion: We demonstrate the DASH and Oxford scoring systems would be useful substitutes for the Constant score, obviating the need for the trained investigator and specialist equipment required to perform the Constant score, alongside the associated cost benefits.

Introduction: Sectioned femoral components retrieved from failed hip resurfacing arthroplasties show resorption of proximal femoral bone or formation of a fibrous membrane at the bone cement interface, in a proportion of cases. We hypothesize that both scenarios create a functional discontinuity zone (FDZ), which exacerbates offloading the proximal bone and promoting resorption. Our study uses finite element modeling to examine the effects of the presence of an FDZ on bone remodeling following hip resurfacing arthroplasty. A radiographic analysis of the proximal femur following hip resurfacing was also conducted in order to draw a comparison to clinical findings.

Methods: The hip resurfacing FE models were oriented in 3 distinct stem-shaft angles: 136 ‘neutral’, 120 ‘varus’ and 150 ‘valgus’. A low-modulus (2 MPa) FDZ (approx. 2 mm thick) was simulated beneath the implant head. Femoral joint and muscle loads were applied to simulate peak joint loading during gait. Interface stress was compared for the normal and simulated FDZ resurfaced femurs. Bone remodeling stimuli was determined using changes in strain energy. A retrospective radiological analysis was undertaken on 98 hips (74 males and 24 females) with a minimum of 5 years follow up. Measurements of the prosthesis-shaft angle, pre–and post-operative femoral head offset and femoral neck diameter at 2 and 5 years were undertaken.

Results: The presence of the simulated FDZ in the FE analysis resulted in increased proximal-medial bone resorption and slightly greater bone formation surrounding the stem. Correspondingly, device-bone interface stresses were found to decrease proximally under the loading platform and increase at the stem, particularly adjacent to the stem-head junction. The valgus BHR femur led to increased resorption, especially around the periphery of the neck and on the medial side. The radiological analysis identified 2 groups; 22 hips (Group 1) had a mean 5.61mm (sd 2.07) reduction in neck diameter over 5 years and 76 hips (Group 2) demonstrated slow reduction in neck diameter, mean 1.13mm (sd 0.97). Neck thinning at 2 and 5 years was significantly greater for Group 1 (p< 0.0001). Group 1 hips had significantly greater reduction in femoral offset (p=0.041), with greater valgus angle oriented components (p=0.09). Reduction in femoral offset was significantly associated with greater valgus orientations (p< 0.0001). The Group 1 revision rate was 36.4% compared to 2.6% in Group 2 (p< 0.0001).

Discussion: The FE results support the hypothesis that the presence of a FDZ decreases load transfer to the proximal bone, resulting in increased medial stress shielding and resorption. These results are consistent with the Group 1 clinical findings. In order to better understand the cause of implant failures in hip resurfacing arthroplasty, additional retrieval studies are necessary.

The potential for bone remodeling in the proximal femur may be detrimental to the long term survival of resurfacing prosthesis.

A retrospective analysis of radiological changes in the femoral neck was undertaken for 96 patients (100 hips, 76 males and 24 females), with a minimum of 5 years following hip resurfacing. The mean age at surgery was 53.8 years. Femoral neck diameter was measured post-operatively, at 2 and 5 years. Pre and post-operative head to neck ratios, femoral head-shaft offset, femoral neck and implant stem-shaft angles were also measured.

Two groups of patients were identified with differing rates of reduction in their femoral neck diameter. Over the first 2 years, Group A (24%) mean reduction was 2.02mm/year while Group B (76%) mean reduction was 0.33 mm/year. At 5 years, the Group A mean reduction was 5.64mm (sd±2.03mm) while Group B reduction was 1.16mm, (sd±0.97mm). The difference was significant at both time points (p< 0.01). Larger head-neck ratios were observed in the group A, both pre and post operatively (p< 0.01).

Finite Element Analysis has predicted stress shielding underneath the femoral head and loading of the mini stem. This may explain bone resorption underneath the shell and remodeling around the mini stem. Compromised blood supply of the retained epiphyseal remnant may also play a part in femoral head resorption. Group A with a larger proportion of females and femoral heads will potentially have a larger proportion of epiphyseal remnant retained. A further mechanism that could be influential in the development of neck thinning and bone resorption may be due to fluid pumping mechanism causing osteolytic erosion at the bone cement interface.

In conclusion, femoral neck thinning is a phenomenon of unproven aetiology which is affecting almost 25% of our resurfacing cases. Further investigations are needed to determine its aetiology and remedy.

Introduction: Measurement of outcome after THR is becoming increasingly important. NICE guidelines have been established and ODEP have stipulated target criteria for the successful evaluation of novel implants. To date, a streamlined, efficient Outcome Programme has not been developed which satisfies the required follow-up criteria. A Programme has been developed at our unit and its evolution is reported.

Methods: A database was created with the assistance of a database developer and an “Outcome Co-ordinator” was appointed to operate the database and manage the programme.

Operation data is now entered onto the database by the surgeon or co-ordinator at the time of surgery. Thereafter, the database automatically produces annual Oxford Hip Questionnaires, EQ-5D questionnaires and invite letters to patients for clinical review at stipulated time-points.

Questionnaires are returned by patients and scanned. This data is then electronically imported to the database without transcription error. Patients attend special Outcome clinics, staffed by Research Fellows and SpR’s, who examine the relevant hip and review their radiographs. The findings are recorded and the paper forms scanned and imported into the database. Non-responders are identified from the database and are chased up via telephone by the coordinator.

Data is extracted from the database with queries and presented using database reports.

Results: 2455 THR’s have been recorded on the database (2127 primaries, 328 revisions) 1937 patients continue under active review for THR. The percentage of patients lost to follow-up is only 2%, 10%, 15% at 2, 5 and 10 years respectively.

Discussion: An efficient system has been developed to maximise the follow-up of patients post THR. The burden on outpatient clinics is reduced and meaningful outcome measures are obtained. The programme could easily be extended to other centres throughout the UK and the benchmarks set by ODEP and NICE can also be attained.