Dislocation is a common and well-studied complication after total hip replacement. However, subluxation, which we define as a clinically recognised episode of incomplete movement of the femoral head outside the acetabulum with spontaneous reduction, has not been studied previously. Out of a total of 2521 hip replacements performed over 12 years by one surgeon, 30 patients experienced subluxations which occurred in 31 arthroplasties. Data were collected prospectively with a minimum follow-up of two years. Subluxation occurred significantly more frequently after revision than after primary hip replacement, and resolved in 19 of 31 cases (61.3%). In six of the 31 hips (19.4%) the patient subsequently dislocated the affected hip, and in six hips (19.4%) intermittent subluxation continued. Four patients had a revision operation for instability, three for recurrent dislocation and one for recurrent subluxation. Clinical and radiological comparisons with a matched group of stable total hips showed no correlation with demographic or radiological parameters.

Patients with subluxing hips reported significantly more concern that their hip would dislocate, more often changed their behaviour to prevent instability and had lower postoperative Harris hip scores than patients with stable replacements.

The aim of this study was to determine whether an osteoplasty of the femoral neck performed at the same time as an intertrochanteric Imhäuser osteotomy led to an improved functional outcome or increased morbidity. A total of 20 hips in 19 patients (12 left, 8 right, 13 male, 6 female), who underwent an Imhäuser intertrochanteric osteotomy following a slipped capital femoral epiphysis were assessed over an eight-year period. A total of 13 hips in 13 patients had an osteoplasty of the femoral neck at the same time. The remaining six patients (seven hips) had intertrochanteric osteotomy alone. The mean age was 15.3 years (13 to 20) with a mean follow-up of 57.8 months (15 to 117); 19 of the slips were severe (Southwick grade III) and one was moderate (grade II), with a mean slip angle of 65.3° (50° to 80°); 17 of the slips were stable and three unstable at initial presentation. The mean Non-Arthritic Hip Scores (NAHS) in patients who underwent osteoplasty was 91.7 (76.3 to 100) and the mean NAHS in patients who did not undergo osteoplasty was 76.6 (41.3 to 100) (p = 0.056). Two patients required a subsequent arthroplasty and neither of these patients had an osteoplasty. No hips developed osteonecrosis or chondrolysis, and there was no increase in complications related to the osteoplasty. We recommend that for patients with a slipped upper femoral epiphysis undergoing an intertrochanteric osteotomy, the addition of an osteoplasty of the femoral neck should be considered.

Cite this article: Bone Joint J 2014;96-B:1119–23.

The radiological evaluation of the anterolateral femoral head is an essential tool for the assessment of the cam type of femoroacetabular impingement. CT, MRI and frog lateral plain radiographs have all been suggested as imaging options for this type of lesion. The alpha angle is accepted as a reliable indicator of the cam type of impingement and may also be used as an assessment for the successful operative correction of the cam lesion.

We studied the alpha angles of 32 consecutive patients with femoroacetabular impingement. The angle measured on frog lateral radiographs using templating tools was compared with that measured on CT scans in order to assess the reliability of the frog lateral view in analysing the alpha angle in cam impingement.

A high interobserver reliability was noted for the assessment of the alpha angle on the frog lateral view with an intraclass correlation coefficient of 0.83. The mean alpha angle measured on the frog lateral view was 58.71° (32° to 83.3°) and that by CT was 65.11° (30° to 102°). A poor intraclass correlation coefficient (0.08) was noted between the measurements using the two systems.

The frog lateral plain radiograph is not reliable for measuring the alpha angle. Various factors may be responsible for this such as the projection of the radiograph, the positioning of the patient and the quality of the image. CT may be necessary for accurate measurement of the alpha angle.

We present our experience of the modified Dunn procedure in combination with a Ganz surgical dislocation of the hip to treat patients with severe slipped capital femoral epiphysis (SCFE). The aim was to prospectively investigate whether this technique is safe and reproducible. We assessed the degree of reduction, functional outcome, rate of complications, radiological changes and range of movement in the hip. There were 28 patients with a mean follow-up of 38.6 months (24 to 84). The lateral slip angle was corrected by a mean of 50.9° (95% confidence interval 44.3 to 57.5). The mean modified Harris hip score at the final follow-up was 89.1 (sd 9.0) and the mean Non-Arthritic Hip score was 91.3 (sd 9.0). Two patients had proven pre-existing avascular necrosis and two developed the condition post-operatively. There were no cases of nonunion, implant failure, infection, deep-vein thrombosis or heterotopic ossification. The range of movement at final follow-up was nearly normal. This study adds to the evidence that the technique of surgical dislocation and anatomical reduction is safe and reliable in patients with SCFE.

Cite this article: Bone Joint J 2013;95-B:424–9.

Conventional growing rods are the most commonly used distraction-based devices in the treatment of progressive early-onset scoliosis. This technique requires repeated lengthenings with the patient anaesthetised in the operating theatre. We describe the outcomes and complications of using a non-invasive magnetically controlled growing rod (MCGR) in children with early-onset scoliosis. Lengthening is performed on an outpatient basis using an external remote control with the patient awake.

Between November 2009 and March 2011, 34 children with a mean age of eight years (5 to 12) underwent treatment. The mean length of follow-up was 15 months (12 to 18). In total, 22 children were treated with dual rod constructs and 12 with a single rod. The mean number of distractions per patient was 4.8 (3 to 6). The mean pre-operative Cobb angle was 69° (46° to 108°); this was corrected to a mean 47° (28° to 91°) post-operatively. The mean Cobb angle at final review was 41° (27° to 86°). The mean pre-operative distance from T1 to S1 was 304 mm (243 to 380) and increased to 335 mm (253 to 400) in the immediate post-operative period. At final review the mean distance from T1 to S1 had increased to 348 mm (260 to 420).

Two patients developed a superficial wound infection and a further two patients in the single rod group developed a loss of distraction. In the dual rod group, one patient had pull-out of a hook and one developed prominent metalwork. Two patients had a rod breakage; one patient in the single rod group and one patient in the dual rod group. Our early results show that the MCGR is safe and effective in the treatment of progressive early-onset scoliosis with the avoidance of repeated surgical lengthenings.

Cite this article: Bone Joint J 2013;95-B:75–80.

The June 2014 Hip & Pelvis Roundup³⁶⁰ looks at: Modular femoral necks: early signs are not good; is corrosion to blame for modular neck failures; metal-on-metal is not quite a closed book; no excess failures in fixation of displaced femoral neck fractures; noise no problem in hip replacement; heterotopic ossification after hip arthroscopy: are NSAIDs the answer?; thrombotic and bleeding events surprisingly low in total joint replacement; and the elephant in the room: complications and surgical volume.

In 2005, we demonstrated that the polished triple-tapered C-stem at two years had migrated distally and rotated internally. From that series, 33 patients have now been followed radiologically, clinically and by radiostereometric analysis (RSA) for up to ten years. The distal migration within the cement mantle had continued and reached a mean of 2 mm (0.5 to 4.0) at ten years. Internal rotation, also within the cement mantle, was a mean 3.8° (external 1.6° to internal 6.6°) The cement mantle did not show any sign of migration or loosening in relation to the femoral bone. There were no clinical or radiological signs indicating that the migration or rotation within the cement mantle had had any adverse effects for the patients.

Cite this article: Bone Joint J 2014;96-B:604–8.

Short uncemented humeral stems can preserve humeral bone stock and facilitate revision surgery but may be prone to malalignment or loosening, especially when used in reverse total shoulder replacement (TSR). We undertook a retrospective review of 44 patients with a mean age of 76 years (59 to 92) who underwent primary reverse TSR with a short uncemented humeral stem. There were 29 females. The indications for joint replacement included cuff tear associated arthropathy (33), avascular necrosis (six), post-traumatic arthritis (two), and inflammatory arthritis (three). At a mean follow-up of 27 months (24 to 40), pain was rated as mild or none in 43 shoulders (97.7%). The mean active elevation improved from 54° (sd 20°) to 142° (sd 25°) and the mean active external rotation from 14° (sd 13°) to 45° (sd 9°). The outcome, as assessed by the modified Neer score, was excellent in 27 (61.3%), satisfactory in 15 (34.1%), and unsatisfactory in two shoulders (4.5%). Stems were well-positioned, without evidence of significant valgus or varus malalignment in 42 TSRs (95.5%). There was no radiological evidence of loosening of the humeral stem in any patient; 13 TSRs (29.5%) had evidence of proximal humeral remodelling and scapular notching was noted in three (6.8%).

Cite this article: Bone Joint J 2014;96-B:526–9.

There is great variability in acetabular component orientation following hip replacement. The aims of this study were to compare the component orientation at impaction with the orientation measured on post-operative radiographs and identify factors that influence the difference between the two. A total of 67 hip replacements (52 total hip replacements and 15 hip resurfacings) were prospectively studied. Intra-operatively, the orientation of the acetabular component after impaction relative to the operating table was measured using a validated stereo-photogrammetry protocol. Post-operatively, the radiographic orientation was measured; the mean inclination/anteversion was 43° (sd 6°)/ 19° (sd 7°). A simulated radiographic orientation was calculated based on how the orientation would have appeared had an on-table radiograph been taken intra-operatively. The mean difference between radiographic and intra-operative inclination/anteversion was 5° (sd 5°)/ -8° (sd 8°). The mean difference between simulated radiographic and intra-operative inclination/anteversion, which quantifies the effect of the different way acetabular orientation is measured, was 3°/-6° (sd 2°). The mean difference between radiographic and simulated radiographic orientation inclination/anteversion, which is a manifestation of the change in pelvic position between component impaction and radiograph, was 1°/-2° (sd 7°).

This study demonstrated that in order to achieve a specific radiographic orientation target, surgeons should implant the acetabular component 5° less inclined and 8° more anteverted than their target. Great variability (2 sd about ± 15°) in the post-operative radiographic cup orientation was seen. The two equally contributing causes for this are variability in the orientation at which the cup is implanted, and the change in pelvic position between impaction and post-operative radiograph.

Cite this article: Bone Joint J 2014;96-B:1290–7

Femoroacetabular impingement causes pain in the hip in young adults and may predispose to the development of osteoarthritis. Genetic factors are important in the aetiology of osteoarthritis of the hip and may have a role in that of femoroacetabular impingement. We compared 96 siblings of 64 patients treated for primary impingement with a spouse control group of 77 individuals. All the subjects were screened clinically and radiologically using a standardised protocol for the presence of cam and pincer deformities and osteoarthritis.

The siblings of those patients with a cam deformity had a relative risk of 2.8 of having the same deformity (66 of 160 siblings hips versus 23 of 154 control hips, p < 0.00001). The siblings of those patients with a pincer deformity had a relative risk of 2.0 of having the same deformity (43 of 116 sibling hips versus 29 of 154 control hips, p = 0.001). Bilateral deformity occurred more often in the siblings (42 of 96 siblings versus 13 of 77 control subjects, relative risk 2.6, p = 0.0002). The prevalence of clinical features in those hips with abnormal morphology was also greater in the sibling group compared with the control group (41 of 109 sibling hips versus 7 of 46 control hips, relative risk 2.5, p = 0.007). In 11 sibling hips there was grade-2 osteoarthritis according to Kellgren and Lawrence versus none in the control group (p = 0.002).

Genetic influences are important in the aetiology of primary femoroacetabular impingement. This risk appears to be manifested through not only abnormal joint morphology, but also through other factors which may modulate progression of the disease.

The lateral compartment is predominantly affected in approximately 10% of patients with osteoarthritis of the knee. The anatomy, kinematics and loading during movement differ considerably between medial and lateral compartments of the knee. This in the main explains the relative protection of the lateral compartment compared with the medial compartment in the development of osteoarthritis. The aetiology of lateral compartment osteoarthritis can be idiopathic, usually affecting the femur, or secondary to trauma commonly affecting the tibia. Surgical management of lateral compartment osteoarthritis can include osteotomy, unicompartmental knee replacement and total knee replacement. This review discusses the biomechanics, pathogenesis and development of lateral compartment osteoarthritis and its management.

Cite this article: Bone Joint J 2013;95-B:436–44.

The purpose of this prospective, randomised study was to evaluate the clinical and radiological results comparing the identical cemented or cementless NexGen total knee prostheses implanted bilaterally in the same patient. Sequential simultaneous bilateral total knee replacements were performed in 50 patients (100 knees). There were 39 women and 11 men with a mean age of 58.4 years (51 to 67) who received a cemented prosthesis in one knee and a cementless prosthesis in the other. The mean follow-up was 13.6 years (13 to 14). At final review, the mean Knee Society scores (96.2 (82 to 100) versus 97.7 (90 to 100)), the mean Western Ontario and McMaster Universities osteoarthritis index (34.5 (4 to 59) versus 35.6 (5 to 51)), the mean ranges of knee movement (124° (100° to 140°) versus 128° (110° to 140°)), mean patient satisfaction (8.1 (sd 1.9) versus 8.3 (sd 1.7)), and radiological results were similar in both groups. The rate of survival of the femoral components was 100% in both groups at 14 years. The rate of survival of the cemented tibial component was 100% and 98% in the cementless tibial component. No osteolysis was identified in either group. Our data have shown no advantage of cementless over cemented components in total knee replacement.

Large-head metal-on-metal total hip replacement has a failure rate of almost 8% at five years, three times the revision rate of conventional hip replacement. Unexplained pain remains a feature of this type of arthroplasty.

All designs of the femoral component of large-head metal-on-metal total hip replacements share a unique characteristic: a subtended angle of 120° defining the proportion of a sphere that the head represents. Using MRI, we measured the contact area of the iliopsoas tendon on the femoral head in sagittal reconstruction of 20 hips of patients with symptomatic femoroacetabular impingement. We also measured the articular extent of the femoral head on 40 normal hips and ten with cam-type deformities. Finally, we performed virtual hip resurfacing on normal and cam-type hips, avoiding overhang of the metal rim inferomedially.

The articular surface of the femoral head has a subtended angle of 120° anteriorly and posteriorly, but only 100° medially. Virtual surgery in a normally shaped femoral head showed a 20° skirt of metal protruding medially where iliopsoas articulates.

The excessive extent of the large-diameter femoral components may cause iliopsoas impingement independently of the acetabular component. This may be the cause of postoperative pain with these implants.

There are no long-term published results on the survival of a third-generation cemented total shoulder replacement. We describe a clinical and radiological study of the Aequalis total shoulder replacement for a minimum of ten years. Between September 1996 and May 1998, 39 consecutive patients underwent a primary cemented total shoulder replacement using this prosthesis. Data were collected prospectively on all patients each year, for a minimum of ten years, or until death or failure of the prosthesis. At a follow-up of at least ten years, 12 patients had died with the prosthesis intact and two had emigrated, leaving 25 available for clinical review. Of these, 13 had rheumatoid arthritis and 12 osteoarthritis. One refused radiological review leaving 24 with fresh radiographs.

Survivorship at ten years was 100% for the humeral component and 92% for the glenoid component. The incidence of lucent lines was low. No humeral component was thought to be at risk and only two glenoid components. The osteoarthritic group gained a mean 65° in forward flexion and their Constant score improved by a mean 41.4 points (13 to 55). The rheumatoid group gained a mean of 24° in flexion and their Constant score improved by 29.4 points. This difference may have been due to failure of the rotator cuff in 75% of the patients with rheumatoid arthritis.

Thus a third-generation total shoulder replacement gives an excellent result in patients with osteoarthritis and an intact rotator cuff. Patients with rheumatoid arthritis have a 75% risk of failure of the rotator cuff at ten years.

We undertook a randomised controlled trial to compare the piriformis-sparing approach with the standard posterior approach used for total hip replacement (THR). We recruited 100 patients awaiting THR and randomly allocated them to either the piriformis-sparing approach or the standard posterior approach. Pre- and post-operative care programmes and rehabilitation regimes were identical for both groups. Observers were blinded to the allocation throughout; patients were blinded until the two-week assessment. Follow-up was at six weeks, three months, one year and two years. In all 11 patients died or were lost to follow-up.

There was no significant difference between groups for any of the functional outcomes. However, for patients in the piriformis-sparing group there was a trend towards a better six-minute walk test at two weeks and greater patient satisfaction at six weeks. The acetabular components were less anteverted (p = 0.005) and had a lower mean inclination angle (p = 0.02) in the piriformis-sparing group. However, in both groups the mean component positions were within Lewinnek’s safe zone. Surgeons perceived the piriformis-sparing approach to be significantly more difficult than the standard approach (p = 0.03), particularly in obese patients.

In conclusion, performing THR through a shorter incision involving sparing piriformis is more difficult and only provides short-term benefits compared with the standard posterior approach.

We examined the placement of the stem in relation to the medial tibial cortex when using total knee replacements (TKRs) with medially-offset tibial stems in Korean patients. Measurements were performed on the pre- and post-operative radiographs of 246 osteoarthritic knees replaced between January 2005 and May 2006 using the Genesis II or E-motion TKR with a medially-offset stem. Pre-operatively, we measured the distance between the mechanical axis and that of the tibial shaft and post-operatively, that between the midline of the tibial stem and the axis of the shaft.

Knees were identified in which there was radiological contact between the tip of the stem and the medial tibial cortex. The mechanical axis was located medial to the axis of the shaft in 203 knees (82.5%). Post-operatively, the midline of the tibial stem was located medial to the tibial shaft axis in 196 knees (79.7%). In 16 knees (6.5%) there was radiological contact between the tibial stem or cement mantle and the medial tibial cortex.

Our study has shown that the medially-offset stem in the tibial component may not be a good option for knees undergoing replacement for advanced osteoarthritis in some Korean patients.

The April 2014 Knee Roundup³⁶⁰ looks at: mobile compression as good as chemical thromboprophylaxis; patellar injury with MIS knee surgery; tibial plateau fracture results not as good as we thought; back and knee pain; metaphyseal sleeves may be the answer in revision knee replacement; oral tranexamic acid; gentamycin alone in antibiotic spacers; and whether the jury is still out on unloader braces.

Cubitus varus is the most frequent complication following the treatment of supracondylar humeral fractures in children. We investigated data from publications reporting on the surgical management of cubitus varus found in electronic searches of Ovid/MEDLINE and Cochrane Library databases. In 894 children from 40 included studies, the mean age at initial injury was 5.7 years (3 to 8.6) and 9.8 years (4 to 15.7) at the time of secondary correction. The four osteotomy techniques were classified as lateral closing wedge, dome, complex (multiplanar) and distraction osteogenesis. A mean angular correction of 27.6º (18.5° to 37.0°) was achieved across all classes of osteotomy. The meta-analytical summary estimate for overall rate of good to excellent results was 87.8% (95% CI 84.4 to 91.2). No technique was shown to significantly affect the surgical outcome, and the risk of complications across all osteotomy classes was 14.5% (95% CI 10.6 to 18.5). Nerve palsies occurred in 2.53% of cases (95% CI 1.4 to 3.6), although 78.4% were transient. No one technique was found to be statistically safer or more effective than any other.

Cite this article: Bone Joint J 2014;96-B:691–700.

Progressive retroversion of a cemented stem is predictive of early loosening and failure. We assessed the relationship between direct post-operative stem anteversion, measured with CT, and the resulting rotational stability, measured with repeated radiostereometric analysis over ten years. The study comprised 60 cemented total hip replacements using one of two types of matt collared stem with a rounded cross-section. The patients were divided into three groups depending on their measured post-operative anteversion (< 10°, 10° to 25°, >  25°). There was a strong correlation between direct post-operative anteversion and later posterior rotation. At one year the < 10° group showed significantly more progressive retroversion together with distal migration, and this persisted to the ten-year follow-up. In the < 10° group four of ten stems (40%) had been revised at ten years, and an additional two stems (20%) were radiologically loose. In the ‘normal’ (10° to 25°) anteversion group there was one revised (3%) and one loose stem (3%) of a total of 30 stems, and in the > 25° group one stem (5%) was revised and another loose (5%) out of 20 stems. This poor outcome is partly dependent on the design of this prosthesis, but the results strongly suggest that the initial rotational position of cemented stems during surgery affects the subsequent progressive retroversion, subsidence and eventual loosening. The degree of retroversion may be sensitive to prosthetic design and stem size, but < 10° of anteversion appears deleterious to the long-term outcome for cemented hip prosthetic stems.

Cite this article: Bone Joint J 2013;95-B:23–30.

The April 2014 Trauma Roundup³⁶⁰ looks at: is it safe to primarily close dog bite wounds?; conservative transfusion evidence based in hip fracture surgery; tibial nonunion is devastating to quality of life; sexual dysfunction after traumatic pelvic fracture; hemiarthroplasty versus fixation in displaced femoral neck fractures; silver VAC dressings “Gold Standard” in massive wounds; dual plating for talar neck fracture; syndesmosis and fibular length easiest errors in ankle fracture surgery; and dual mobility: stable as a rock in fracture.