Objectives

Excessive acetabular coverage is the most common cause of pincer-type femoroacetabular impingement. To date, an association between acetabular over-coverage and genetic variations has not been studied. In this study we investigated the association between single nucleotide polymorphisms (SNPs) of paralogous Homeobox (HOX)9 genes and acetabular coverage in Japanese individuals to identify a possible genetic variation associated with acetabular over-coverage.

The aim of this study was to assess the effect of frictional torque and bending moment on fretting corrosion at the taper interface of a modular femoral component and to investigate whether different combinations of material also had an effect. The combinations we examined were 1) cobalt–chromium (CoCr) heads on CoCr stems 2) CoCr heads on titanium alloy (Ti) stems and 3) ceramic heads on CoCr stems.

In test 1 increasing torque was imposed by offsetting the stem in the anteroposterior plane in increments of 0 mm, 4 mm, 6 mm and 8 mm when the torque generated was equivalent to 0 Nm, 9 Nm, 14 Nm and 18 Nm.

In test 2 we investigated the effect of increasing the bending moment by offsetting the application of axial load from the midline in the mediolateral plane. Increments of offset equivalent to head + 0 mm, head + 7 mm and head + 14 mm were used.

Significantly higher currents and amplitudes were seen with increasing torque for all combinations of material. However, Ti stems showed the highest corrosion currents. Increased bending moments associated with using larger offset heads produced more corrosion: Ti stems generally performed worse than CoCr stems. Using ceramic heads did not prevent corrosion, but reduced it significantly in all loading configurations.

Cite this article: Bone Joint J 2015;97-B:463–72.

Objectives

The major problem with repair of an articular cartilage injury is the extensive difference in the structure and function of regenerated, compared with normal cartilage. Our work investigates the feasibility of repairing articular osteochondral defects in the canine knee joint using a composite lamellar scaffold of nano-ß-tricalcium phosphate (ß-TCP)/collagen (col) I and II with bone marrow stromal stem cells (BMSCs) and assesses its biological compatibility.

The natural history of primary anterior dislocation of the glenohumeral joint in adolescent patients remains unclear and there is no consensus for management of these patients.

The objectives of this study were to report the natural history of primary anterior dislocation of the glenohumeral joint in adolescent patients and to identify the risk factors for recurrent dislocation.

We reviewed prospectively-collected clinical and radiological data on 133 adolescent patients diagnosed with a primary anterior dislocation of the glenohumeral joint who had been managed non-operatively at our hospital between 1996 and 2008. There were 115 male (86.5%) and 18 female patients (13.5%) with a mean age of 16.3 years (13 to 18) and a mean follow-up of 95.2 months (1 to 215).

During follow-up, 102 (absolute incidence of 76.7%) patients had a recurrent dislocation. The median interval between primary and recurrent dislocation was ten months (95% CI 7.4 to 12.6). Applying survival analysis the likelihood of having a stable shoulder one year after the initial injury was 59% (95% CI 51.2 to 66.8), 38% (95% CI 30.2 to 45.8%) after two years, 21% (95% CI 13.2 to 28.8) after five years, and 7% (95% CI 1.1 to 12.9) after ten years. Neither age nor gender significantly predicted recurrent dislocation during follow-up.

We conclude that adolescent patients with a primary anterior dislocation of the glenohumeral joint have a high rate of recurrent dislocation, which usually occurs within two years of their initial injury: these patients should be considered for early operative stabilisation.

Cite this article: Bone Joint J 2015;97-B:520–6.

Our aim was to compare the outcome of arthroscopic release for frozen shoulder in patients with and without diabetes. We prospectively compared the outcome in 21 patients with and 21 patients without diabetes, two years post-operatively. The modified Constant score was used as the outcome measure. The mean age of the patients was 54.5 years (48 to 65; male:female ratio: 18:24), the mean pre-operative duration of symptoms was 8.3 months (6 to 13) and the mean pre-operative modified Constant scores were 36.6 (standard deviation (sd) 4.6) and 38.4 (sd 5.7) in the diabetic and non-diabetic groups, respectively. The mean modified Constant scores at six weeks, six months and two years post-operatively in the diabetics were 55. 6 (sd 4.7), 67. 4 (sd 5.6) and 84. 4 (sd 6.8), respectively; and in the non-diabetics 66.8 (sd 4.5), 79.6 (sd 3.8) and 88.6 (sd 4.2), respectively. A total of 15 (71%) of diabetic patients recovered a full range of movement as opposed to 19 (90%) in the non-diabetics. There was significant improvement (p < 0.01) in the modified Constant scores following arthroscopic release for frozen shoulder in both groups. The results in diabetics were significantly worse than those in non-diabetics six months post-operatively (p < 0.01) with a tendency towards persistent limitation of movement two years after operation. These results may be used when counselling diabetic patients for the outcome after arthroscopic treatment of frozen shoulder.

Cite this article: Bone Joint J 2014;96-B:1355–8.

We report the results of Vulpius transverse gastrocsoleus recession for equinus gait in 26 children with cerebral palsy (CP), using the Gait Profile Score (GPS), Gait Variable Scores (GVS) and movement analysis profile. All children had an equinus deformity on physical examination and equinus gait on three-dimensional gait analysis prior to surgery. The pre-operative and post-operative GPS and GVS were statistically analysed. There were 20 boys and 6 girls in the study cohort with a mean age at surgery of 9.2 years (5.1 to 17.7) and 11.5 years (7.3 to 20.8) at follow-up. Of the 26 children, 14 had spastic diplegia and 12 spastic hemiplegia. Gait function improved for the cohort, confirmed by a decrease in mean GPS from 13.4° pre-operatively to 9.0° final review (p < 0.001). The change was 2.8 times the minimal clinically important difference (MCID). Thus the improvements in gait were both clinically and statistically significant. The transverse gastrocsoleus recession described by Vulpius is an effective procedure for equinus gait in selected children with CP, when there is a fixed contracture of the gastrocnemius and soleus muscles.

Cite this article: Bone Joint J 2015;97-B:564–71.

This study demonstrates a significant correlation between the American Knee Society (AKS) Clinical Rating System and the Oxford Knee Score (OKS) and provides a validated prediction tool to estimate score conversion.

A total of 1022 patients were prospectively clinically assessed five years after TKR and completed AKS assessments and an OKS questionnaire. Multivariate regression analysis demonstrated significant correlations between OKS and the AKS knee and function scores but a stronger correlation (r = 0.68, p < 0.001) when using the sum of the AKS knee and function scores. Addition of body mass index and age (other statistically significant predictors of OKS) to the algorithm did not significantly increase the predictive value.

The simple regression model was used to predict the OKS in a group of 236 patients who were clinically assessed nine to ten years after TKR using the AKS system. The predicted OKS was compared with actual OKS in the second group. Intra-class correlation demonstrated excellent reliability (r = 0.81, 95% confidence intervals 0.75 to 0.85) for the combined knee and function score when used to predict OKS.

Our findings will facilitate comparison of outcome data from studies and registries using either the OKS or the AKS scores and may also be of value for those undertaking meta-analyses and systematic reviews.

Cite this article: Bone Joint J 2015;97-B:503–9.

We hypothesised that a minimally invasive peroneus brevis tendon transfer would be effective for the management of a chronic rupture of the Achilles tendon. In 17 patients (three women, 14 men) who underwent minimally invasive transfer and tenodesis of the peroneus brevis to the calcaneum, at a mean follow-up of 4.6 years (2 to 7) the modified Achilles tendon total rupture score (ATRS) was recorded and the maximum circumference of the calf of the operated and contralateral limbs was measured. The strength of isometric plantar flexion of the gastrocsoleus complex and of eversion of the ankle were measured bilaterally. Functional outcomes were classified according to the four-point Boyden scale.

At the latest review, the mean maximum circumference of the calf of the operated limb was not significantly different from the pre-operative mean value, (41.4 cm, 32 to 50 vs 40.6 cm, 33 to 46; p = 0.45), and not significantly less than that of the contralateral limb (43.1 cm, 35 to 52; p = 0.16). The mean peak torque (244.6 N, 125 to 367) and the strength of eversion of the operated ankle (149.1 N, 65 to 240) were significantly lower (p < 0.01) than those of the contralateral limb (mean peak torque 289, 145 to 419; strength of eversion: 175.2, 71 to 280). The mean ATRS significantly improved from 58 pre-operatively (35 to 68) to 91 (75 to 97; 95% confidence interval 85.3 to 93.2) at the time of final review. Of 13 patients who practised sport at the time of injury, ten still undertook recreational activities.

This procedure may be safely performed, is minimally invasive, and allows most patients to return to pre-injury sport and daily activities.

Cite this article: Bone Joint J 2015;97-B:353–7.

In this in vitro study of the hip joint we examined which soft tissues act as primary and secondary passive rotational restraints when the hip joint is functionally loaded. A total of nine cadaveric left hips were mounted in a testing rig that allowed the application of forces, torques and rotations in all six degrees of freedom. The hip was rotated throughout a complete range of movement (ROM) and the contributions of the iliofemoral (medial and lateral arms), pubofemoral and ischiofemoral ligaments and the ligamentum teres to rotational restraint was determined by resecting a ligament and measuring the reduced torque required to achieve the same angular position as before resection. The contribution from the acetabular labrum was also measured. Each of the capsular ligaments acted as the primary hip rotation restraint somewhere within the complete ROM, and the ligamentum teres acted as a secondary restraint in high flexion, adduction and external rotation. The iliofemoral lateral arm and the ischiofemoral ligaments were primary restraints in two-thirds of the positions tested. Appreciation of the importance of these structures in preventing excessive hip rotation and subsequent impingement/instability may be relevant for surgeons undertaking both hip joint preserving surgery and hip arthroplasty.

Cite this article: Bone Joint J 2015; 97-B:484–91.

Pigmented villonodular synovitis (PVNS) is a rare proliferative process of the synovium which most commonly affects the knee and occurs in either a localised (LPVNS) or a diffuse form (DPVNS). The effect of different methods of surgical synovectomy and adjuvant radiotherapy on the rate of recurrence is unclear. We conducted a systematic review and identified 35 observational studies in English which reported the use of surgical synovectomy to treat PVNS of the knee.

A meta-analysis included 630 patients, 137 (21.8%) of whom had a recurrence after synovectomy. For patients with DPVNS, low-quality evidence found that the rate of recurrence was reduced by both open synovectomy (odds ration (OR) = 0.47; 95% CI 0.25 to 0.90; p = 0.024) and combined open and arthroscopic synovectomy (OR = 0.19, 95% CI = 0.06 to 0.58; p = 0.003) compared with arthroscopic surgery. Very low-quality evidence found that the rate of recurrence of DPVNS was reduced by peri-operative radiotherapy (OR = 0.31, 95% CI 0.14 to 0.70; p = 0.01). Very low-quality evidence suggested that the rate of recurrence of LPVNS was not related to the surgical approach.

This meta-analysis suggests that open synovectomy or synovectomy combined with peri-operative radiotherapy for DPVNS is associated with a reduced rate of recurrence. Large long-term prospective multicentre observational studies, with a focus on both rate of recurrence and function, are required to confirm these findings.

Cite this article: Bone Joint J 2015;97-B:550–7.

We undertook a retrospective cohort study to determine clinical outcomes following the revision of metal-on-metal (MoM) hip replacements for adverse reaction to metal debris (ARMD), and to identify predictors of time to revision and outcomes following revision. Between 1998 and 2012 a total of 64 MoM hips (mean age at revision of 57.8 years; 46 (72%) female; 46 (72%) hip resurfacings and 18 (28%) total hip replacements) were revised for ARMD at one specialist centre. At a mean follow-up of 4.5 years (1.0 to 14.6) from revision for ARMD there were 13 hips (20.3%) with post-operative complications and eight (12.5%) requiring re-revision.

The Kaplan–Meier five-year survival rate for ARMD revision was 87.9% (95% confidence interval 78.9 to 98.0; 19 hips at risk). Excluding re-revisions, the median absolute Oxford hip score (OHS) following ARMD revision using the percentage method (0% best outcome and 100% worst outcome) was 18.8% (interquartile range (IQR) 7.8% to 48.3%), which is equivalent to 39/48 (IQR 24.8/48 to 44.3/48) when using the modified OHS. Histopathological response did not affect time to revision for ARMD (p = 0.334) or the subsequent risk of re-revision (p = 0.879). Similarly, the presence or absence of a contralateral MoM hip bearing did not affect time to revision for ARMD (p = 0.066) or the subsequent risk of re-revision (p = 0.178).

Patients revised to MoM bearings had higher rates of re-revision (five of 16 MoM hips re-revised; p = 0.046), but those not requiring re-revision had good functional results (median absolute OHS 14.6% or 41.0/48). Short-term morbidity following revision for ARMD was comparable with previous reports. Caution should be exercised when choosing bearing surfaces for ARMD revisions.

Cite this article: Bone Joint J 2014;96-B:1600–9.

Revision total hip arthroplasty (THA) is challenging when there is severe loss of bone in the proximal femur. The purpose of this study was to evaluate the clinical and radiographic outcomes of revision THA in patients with severe proximal femoral bone loss treated with a fluted, tapered, modular femoral component. Between January 1998 and December 2004, 92 revision THAs were performed in 92 patients using a single fluted, tapered, modular femoral stem design. Pre-operative diagnoses included aseptic loosening, infection and peri-prosthetic fracture. Bone loss was categorised pre-operatively as Paprosky types III-IV, or Vancouver B3 in patients with a peri-prosthetic fracture. The mean clinical follow-up was 6.4 years (2 to 12). A total of 47 patients had peri-operative complications, 27 of whom required further surgery. However, most of these further operations involved retention of a well-fixed femoral stem, and 88/92 femoral components (97%) remained in situ. Of the four components requiring revision, three were revised for infection and were well fixed at the time of revision; only one (1%) was revised for aseptic loosening. The most common complications were post-operative instability (17 hips, 19%) and intra-operative femoral fracture during insertion of the stem (11 hips, 12%). Diaphyseal stress shielding was noted in 20 hips (22%). There were no fractures of the femoral component. At the final follow-up 78% of patients had minimal or no pain.

Revision THA in patients with extensive proximal femoral bone loss using the Link MP fluted, tapered, modular stem led to a high rate of osseointegration of the stem at mid-term follow-up.

Cite this article: Bone Joint J 2015; 97-B:312–17.

Graft-tunnel mismatch of the bone-patellar tendon-bone (BPTB) graft is a major concern during anatomical anterior cruciate ligament (ACL) reconstruction if the femoral tunnel is positioned using a far medial portal technique, as the femoral tunnel tends to be shorter compared with that positioned using a transtibial portal technique. This study describes an accurate method of calculating the ideal length of bone plugs of a BPTB graft required to avoid graft–tunnel mismatch during anatomical ACL reconstruction using a far medial portal technique of femoral tunnel positioning.

Based on data obtained intra-operatively from 60 anatomical ACL reconstruction procedures, we calculated the length of bone plugs required in the BPTB graft to avoid graft–tunnel mismatch. When this was prevented in all the 60 cases, we found that the mean length of femoral bone plug that remained in contact with the interference screw within the femoral tunnel was 14 mm (12 to 22) and the mean length of tibial bone plug that remained in contact with the interference screw within the tibial tunnel was 23 mm (18 to 28). These results were used to validate theoretical formulae developed to predict the required length of bone plugs in BPTB graft during anatomical ACL reconstruction using a far medial portal technique.

Cite this article: Bone Joint J 2015;97-B:324–8.

Femoral stem version has a major influence on impingement and early post-operative stability after total hip arthroplasty (THA).

The main objective of this study was to evaluate the validity of a novel radiological method for measuring stem version. Anteroposterior (AP) radiographs and three-dimensional CT scans were obtained for 115 patients (female/male 63/72, mean age 62.5 years (50 to 75)) who had undergone minimally invasive, cementless THA. Stem version was calculated from the AP hip radiograph by rotation-based change in the projected prosthetic neck–shaft (NSA*) angle using the mathematical formula ST = arcos [tan (NSA*) / tan (135)]. We used two independent observers who repeated the analysis after a six-week interval. Radiological measurements were compared with 3D-CT measurements by an independent, blinded external institute.

We found a mean difference of 1.2° (sd 6.2) between radiological and 3D-CT measurements of stem version. The correlation between the mean radiological and 3D-CT stem torsion was r = 0.88 (p < 0.001). The intra- (intraclass correlation coefficient ≥ 0.94) and inter-observer agreement (mean concordance correlation coefficient = 0.87) for the radiological measurements were excellent.

We found that femoral tilt was associated with the mean radiological measurement error (r = 0.22, p = 0.02).

The projected neck–shaft angle is a reliable method for measuring stem version on AP radiographs of the hip after a THA. However, a highly standardised radiological technique is required for its precise measurement.

Cite this article: Bone Joint J 2015; 97-B:306–11.

Ceramic-on-metal (CoM) is a relatively new bearing combination for total hip arthroplasty (THA) with few reported outcomes. A total of 287 CoM THAs were carried out in 271 patients (mean age 55.6 years (20 to 77), 150 THAs in female patients, 137 in male) under the care of a single surgeon between October 2007 and October 2009. With the issues surrounding metal-on-metal bearings the decision was taken to review these patients between March and November 2011, at a mean follow-up of 34 months (23 to 45) and to record pain, outcome scores, radiological analysis and blood ion levels. The mean Oxford Hip Score was 19.2 (12 to 53), 254 patients with 268 hips (95%) had mild/very mild/no pain, the mean angle of inclination of the acetabular component was 44.8^o (28^o to 63^o), 82 stems (29%) had evidence of radiolucent lines of > 1 mm in at least one Gruen zone and the median levels of cobalt and chromium ions in the blood were 0.83 μg/L (0.24 μg/L to 27.56 μg/L) and 0.78 μg/L (0.21 μg/L to 8.84 μg/L), respectively. The five-year survival rate is 96.9% (95% confidence interval 94.7% to 99%).

Due to the presence of radiolucent lines and the higher than expected levels of metal ions in the blood, we would not recommend the use of CoM THA without further long-term follow-up. We plan to monitor all these patients regularly.

Cite this article: Bone Joint J 2015;97-B:300–5.

Minimal clinically important differences (MCID) in the scores of patient-reported outcome measures allow clinicians to assess the outcome of intervention from the perspective of the patient. There has been significant variation in their absolute values in previous publications and a lack of consistency in their calculation.

The purpose of this study was first, to establish whether these values, following spinal surgery, vary depending on the surgical intervention and their method of calculation and secondly, to assess whether there is any correlation between the two external anchors most frequently used to calculate the MCID.

We carried out a retrospective analysis of prospectively gathered data of adult patients who underwent elective spinal surgery between 1994 and 2009. A total of 244 patients were included. There were 125 men and 119 women with a mean age of 54 years (16 to 84); the mean follow-up was 62 months (6 to 199) The MCID was calculated using three previously published methods.

Our results show that the value of the MCID varies considerably with the operation and its method of calculation. There was good correlation between the two external anchors. The global outcome tool correlated significantly better.

We conclude that consensus needs to be reached on the best method of calculating the MCID. This then needs to be defined for each spinal procedure. Using a blanket value for the MCID for all spinal procedures should be avoided.

Cite this article: Bone Joint J 2015;97-B:366–71.

Flexor digitorum longus transfer and medial displacement calcaneal osteotomy is a well-recognised form of treatment for stage II posterior tibial tendon dysfunction. Although excellent short- and medium-term results have been reported, the long-term outcome is unknown. We reviewed the clinical outcome of 31 patients with a symptomatic flexible flat-foot deformity who underwent this procedure between 1994 and 1996. There were 21 women and ten men with a mean age of 54.3 years (42 to 70). The mean follow-up was 15.2 years (11.4 to 16.5). All scores improved significantly (p < 0.001). The mean American Orthopedic Foot and Ankle Society (AOFAS) score improved from 48.4 pre-operatively to 90.3 (54 to 100) at the final follow-up. The mean pain component improved from 12.3 to 35.2 (20 to 40). The mean function score improved from 35.2 to 45.6 (30 to 50). The mean visual analogue score for pain improved from 7.3 to 1.3 (0 to 6). The mean Short Form-36 physical component score was 40.6 (sd 8.9), and this showed a significant correlation with the mean AOFAS score (r = 0.68, p = 0.005). A total of 27 patients (87%) were pain free and functioning well at the final follow-up. We believe that flexor digitorum longus transfer and calcaneal osteotomy provides long-term pain relief and satisfactory function in the treatment of stage II posterior tibial tendon dysfunction.

Cite this article: Bone Joint J 2015;97-B:346–52.

The long-term survival of the cementless Spotorno CLS femoral component in patients aged > 50 years at the time of arthroplasty was investigated. Survivorship analysis of a consecutive series of 85 patients (100 hips; under 50 years of age at a mean follow-up of 18.4 years (16.3 to 20.8)) was performed. The clinical and radiographic outcomes were satisfactory. The overall rate of survival of the femoral component was 93.5% (95% confidence interval (CI), 90.9 to 96.1) after 19 years. Survival with revision for aseptic loosening as the end point was 95.7% (95% CI 93.6 to 97.8%) at 19 years.

This study demonstrates an excellent long-term survival of the Spotorno CLS femoral component after 16 to 20 years in young patients undergoing total hip arthroplasty.

Cite this article: Bone Joint J 2015;97-B:160–3.

In this study we evaluated whether pre-operative Western Ontario and McMaster Universities (WOMAC) osteoarthritis scores can predict satisfaction following total hip arthroplasty (THA). Prospective data for a cohort of patients undergoing THA from two large academic centres were collected, and pre-operative and one-year post-operative WOMAC scores and a 25-point satisfaction questionnaire were obtained for 446 patients. Satisfaction scores were dichotomised into either improvement or deterioration. Scatter plots and Spearman’s rank correlation coefficient were used to describe the association between pre-operative WOMAC and one-year post-operative WOMAC scores and patient satisfaction. Satisfaction was compared using receiver operating characteristic (ROC) analysis against pre-operative, post-operative and δ WOMAC scores.

We found no relationship between pre-operative WOMAC scores and one-year post-operative WOMAC or satisfaction scores, with Spearman’s rank correlation coefficients of 0.16 and –0.05, respectively. The ROC analysis showed areas under the curve (AUC) of 0.54 (pre-operative WOMAC), 0.67 (post-operative WOMAC) and 0.43 (δ WOMAC), respectively, for an improvement in satisfaction.

We conclude that the pre-operative WOMAC score does not predict the post-operative WOMAC score or patient satisfaction after THA, and that WOMAC scores can therefore not be used to prioritise patient care.

Cite this article: Bone Joint J 2015;97-B:150–3.

The treatment of infected nonunions is difficult. Antibiotic cement-coated (ACC) rods provide stability as well as delivering antibiotics. We conducted a review of 110 infected nonunions treated with ACC rods. Patients were divided into two groups: group A (67 patients) with an infected arthrodesis, and group B (43 patients) with an infected nonunion in a long bone. In group A, infected arthrodesis, the success rate after the first procedure was 38/67 (57%), 29/67 (43%) required further surgery for either control of infection or non-union. At last follow-up, five patients required amputation, representing a limb salvage rate of 62/67 (93%) overall. In all, 29/67 (43%) presented with a bone defect with a mean size of 6.78 cm (2 to 25). Of those with a bone defect, 13/29 (45%) required further surgery and had a mean size of defect of 7.2 cm (3.5 to 25). The cultures were negative in 17/67 (26%) and the most common organism cultured was methicillin-resistant staphylococcus aureus (MRSA) (23/67, (35%)). In group B, long bones nonunion, the success rate after the first procedure was 26/43 (60%), 17/43 (40%) required further surgery for either control of infection or nonunion. The limb salvage rate at last follow-up was 43/43 (100%). A total of 22/43 (51%) had bone defect with a mean size of 4.7 cm (1.5 to 11.5). Of those patients with a bone defect, 93% required further surgery with a mean size of defect of 5.4 cm (3 to 8.5). The cultures were negative in 10/43 (24%) and the most common organism cultured was MRSA, 15/43 (35%). ACC rods are an effective form of treatment for an infected nonunion, with an acceptable rate of complications.

Cite this article: Bone Joint J 2014; 96-B:1349–54