We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate regions of interest of the femoral neck and in the calcar region corresponding to Gruen zone 7 for the hip resurfacing group and compared only to the calcar region in the total hip replacement group. Standardised measurements were performed pre-operatively and after three, six and 12 months. The groups were well matched in terms of gender distribution and mean age.

The mean BMD in the calcar region increased after one year to 105.2% of baseline levels in the resurfaced group compared with a significant decrease to 82.1% in the total hip replacement group (p < 0.001) by 12 months. For the resurfaced group, there was a decrease in bone density in all four regions of the femoral neck at three months which did not reach statistical significance and was followed by recovery to baseline levels after 12 months.

Hip resurfacing did indeed preserve BMD in the inferior femoral neck. In contrast, a decrease in the mean BMD in Gruen zone 7 followed uncemented distally fixed total hip replacement. Long term follow-up studies are necessary to see whether this benefit in preservation of BMD will be clinically relevant at future revision surgery.

The relationship between post-operative bone density and subsequent failure of total knee replacement (TKR) is not known. This retrospective study aimed to determine the relationship between bone density and failure, both overall and according to failure mechanism. All 54 aseptic failures occurring in 50 patients from 7760 consecutive primary cemented TKRs between 1983 and 2004 were matched with non-failing TKRs, and 47 failures in 44 patients involved tibial failures with the matching characteristics of age (65.1 for failed and 69.8 for non-failed), gender (70.2% female), diagnosis (93.6% OA), date of operation, bilaterality, pre-operative alignment (0.4 and 0.3 respectively), and body mass index (30.2 and 30.0 respectively). In each case, the density of bone beneath the tibial component was assessed at each follow-up interval using standardised, calibrated radiographs. Failing knees were compared with controls both overall and, as a subgroup analysis, by failure mechanism. Knees were compared with controls using univariable linear regression.

Significant and continuous elevation in tibial density was found in knees that eventually failed by medial collapse (p < 0.001) and progressive radiolucency (p < 0.001) compared with controls, particularly in the medial region of the tibia. Knees failing due to ligamentous instability demonstrated an initial decline in density (p = 0.0152) followed by a non-decreasing density over time (p = 0.034 for equivalence). Non-failing knees reported a decline in density similar to that reported previously using dual-energy x-ray absorptiometry (DEXA). Differences between failing and non-failing knees were observable as early as two months following surgery. This tool may be used to identify patients at risk of failure following TKR, but more validation work is needed.

Cite this article: Bone Joint J 2014;96-B:1503–9.

The December 2013 Research Roundup³⁶⁰ looks at: Inflammation implicated in FAI; Ponseti and effective teaching; Unicompartmental knee design and tibial strain; Bisphosphonates and fracture healing; Antibiosis in cement; Zoledronic acid improves primary stability in revision?; Osteoporotic fractures revisited; and electroarthrography for monitoring of cartilage degeneration

The purpose of this study was to identify changing trends in the pattern of distribution of the type and demographics of fractures of the hip in the elderly between 2001 and 2010. A retrospective cross-sectional comparison was conducted between 179 fractures of the hip treated in 2001, 357 treated in 2006 and 454 treated in 2010. Patients aged < 60 years and those with pathological and peri-prosthetic fractures were excluded. Fractures were classified as stable extracapsular, unstable extracapsular or intracapsular fractures.

The mean age of the 179 patients (132 women (73.7%)) treated in 2001 was 80.8 years (60 to 96), 81.8 years (61 to 101) in the 357 patients (251 women (70.3%)) treated in 2006 and 82.0 years (61 to 102) in the 454 patients (321 women (70.1%)) treated in 2010 (p = 0.17). There was no difference in the gender distribution between the three study years (p = 0.68).

The main finding was a steep rise in the proportion of unstable peritrochanteric fractures. The proportion of unstable extracapsular fractures was 32% (n = 57) in 2001, 35% (n = 125) in 2006 and 45% (n = 204) in 2010 (p < 0.001). This increase was not significant in patients aged between 60 and 69 years (p = 0.84), marginally significant in those aged between 70 and 79 years (p = 0.04) and very significant in those aged > 80 years (p < 0.001). The proportion of intracapsular fractures did not change (p = 0.94).

At present, we face not only an increasing number of fractures of the hip, but more demanding and complex fractures in older patients than a decade ago. This study does not provide an explanation for this change.

Cite this article: Bone Joint J 2013;95-B:1250–4.

The June 2013 Hip & Pelvis Roundup³⁶⁰ looks at: failure in metal-on-metal arthroplasty; minimal hip approaches; whether bisphosphonates improve femoral bone stock following arthroplasty; whether more fat means more operative time; surgical infection; vascularised fibular graft for osteonecrosis; subclinical SUFE; and dentists, hips and antibiotics.

We investigated a new intramedullary locking nail that allows the distal interlocking screws to be locked to the nail. We compared fixation using this new implant with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. A total of 15 human cadaver femora were used to simulate an AO 33-A3 fracture pattern. Paired specimens compared fixation using either a locking or non-locking retrograde nail, and using either a locking retrograde nail or a locking plate. The constructs underwent cyclical loading to simulate single-leg stance up to 125 000 cycles. Axial and torsional stiffness and displacement, cycles to failure and modes of failure were recorded for each specimen. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life (75 800 cycles (sd 33 900) vs 12 800 cycles (sd 6100); p = 0.007) and mean axial stiffness (220 N/mm (sd 80) vs 70 N/mm (sd 18); p = 0.005), but lower mean torsional stiffness (2.5 Nm/° (sd 0.9) vs 5.1 Nm/° (sd 1.5); p = 0.008). In addition, in the nail group the mode of failure was either cut-out of the distal screws or breakage of nails, and in the locking plate group breakage of the plate was always the mode of failure. Locking nail constructs had significantly longer mean fatigue life than non-locking nail constructs (78 900 cycles (sd 25 600) vs 52 400 cycles (sd 22 500); p = 0.04).

The new locking retrograde femoral nail showed better stiffness and fatigue life than locking plates, and superior fatigue life to non-locking nails, which may be advantageous in elderly patients.

Cite this article: Bone Joint J 2014;96-B:114–21.

Stress shielding resulting in diminished bone density following total knee replacement (TKR) may increase the risk of migration and loosening of the prosthesis. This retrospective study was designed to quantify the effects of the method of fixation on peri-prosthetic tibial bone density beneath cemented and uncemented tibial components of similar design and with similar long-term survival rates. Standard radiographs taken between two months and 15 years post-operatively were digitised from a matched group of TKRs using cemented (n = 67) and uncemented (n = 67) AGC tibial prostheses. Digital radiograph densitometry was used to quantify changes in bone density over time. Age, length of follow-up, gender, body mass index and alignment each significantly influenced the long-term pattern of peri-prosthetic bone density. Similar long-term changes in density irrespective of the method of fixation correlated well with the high rate of survival of this TKR at 20 years, and suggest that cemented and uncemented fixation are both equally viable.

Cite this article: Bone Joint J 2013;95-B:911–16.

The osteoinductive properties of demineralised bone matrix have been demonstrated in animal studies. However, its therapeutic efficacy has yet to be proven in humans. The clinical properties of AlloMatrix, an injectable calcium-based demineralised bone matrix allograft, were studied in a prospective randomised study of 50 patients with an isolated unstable distal radial fracture treated by reduction and Kirschner (K-) wire fixation. A total of 24 patients were randomised to the graft group (13 men and 11 women, mean age 42.3 years (20 to 62)) and 26 to the no graft group (8 men and 18 women, mean age 45.0 years (17 to 69)).

At one, three, six and nine weeks, and six and 12 months post-operatively, patients underwent radiological evaluation, assessments for range of movement, grip and pinch strength, and also completed the Disabilities of Arm, Shoulder and Hand questionnaire. At one and six weeks and one year post-operatively, bone mineral density evaluations of both wrists were performed.

No significant difference in wrist function and speed of recovery, rate of union, complications or bone mineral density was found between the two groups. The operating time was significantly higher in the graft group (p = 0.004). Radiologically, the reduction parameters remained similar in the two groups and all AlloMatrix extraosseous leakages disappeared after nine weeks.

This prospective randomised controlled trial did not demonstrate a beneficial effect of AlloMatrix demineralised bone matrix in the treatment of this category of distal radial fractures treated by K-wire fixation.

Cite this article: Bone Joint J 2013;95-B:1514–20.

We matched 78 patients with a loose cemented Charnley Elite Plus total hip replacement (THR) by age, gender, race, prosthesis and time from surgery with 49 patients with a well-fixed stable hip replacement, to determine if poor bone quality predisposes to loosening. Clinical, radiological, biomechanical and bone mineral density indicators of bone quality were assessed.

Patients with loose replacements had more pain, were more likely to have presented with atrophic arthritis and to have a history of fragility fracture, narrower femoral cortices and lower peri-prosthetic or lumbar spine bone mineral density (all t-test, p < 0.01). They also tended to be smokers (chi-squared test, p = 0.08). Vitamin-D deficiency was common, but not significantly different between the two groups (t-test, p = 0.31)

In this series of cemented hip replacements performed between 1994 and 1998, aseptic loosening was associated with poor bone quality. Patients with a THR should be screened for osteoporosis and have regular radiological surveillance.

Osteoporosis and fragility fractures in men constitute a considerable burden in healthcare. We have reviewed 2035 men aged over 50 years with 2142 fractures to clarify the epidemiology of these injuries and their underlying risk factors. The prevalence of osteoporosis ranged between 17.5% in fractures of the ankle and 57.8% in those of the hip. The main risk factors associated with osteoporosis were smoking (47.4%), alcohol excess (36.2%), body mass index < 21 (12.8%) and a family history of osteoporosis (8.4%). Immobility, smoking, self-reported alcohol excess, a low body mass index, age ≥72 and loss in height were significantly more common among men with fractures of the hip than in those with fractures elsewhere.

The purpose of this study was to evaluate the risk of late displacement after the treatment of distal radial fractures with a locking volar plate, and to investigate the clinical and radiological factors that might correlate with re-displacement. From March 2007 to October 2009, 120 of an original cohort of 132 female patients with unstable fractures of the distal radius were treated with a volar locking plate, and were studied over a follow-up period of six months. In the immediate post-operative and final follow-up radiographs, late displacement was evaluated as judged by ulnar variance, radial inclination, and dorsal angulation. We also analysed the correlation of a variety of clinical and radiological factors with re-displacement. Ulnar variance was significantly overcorrected (p < 0.001) while radial inclination and dorsal angulation were undercorrected when compared statistically (p <  0.001) with the unaffected side in the immediate post-operative stage. During follow-up, radial shortening and dorsal angulation progressed statistically, but none had a value beyond the acceptable range. Bone mineral density measured at the proximal femur and the position of the screws in the subchondral region, correlated with slight progressive radial shortening, which was not clinically relevant.

Volar locking plating of distal radial fractures is a reliable form of treatment without substantial late displacement.

Cite this article: Bone Joint J 2013;95-B:396–400.

The October 2012 Oncology Roundup³⁶⁰ looks at: the causes of primary bone tumours; adjuvant chemotherapy in the longer term; vascularised fibular grafts to salvage massive femoral allografts; a new look at old risks; reconstruction with excised irradiated bone; predicting chemosensitivity in osteosarcoma ; and chemotherapy, osteoporosis and the risk of fracture.

The October 2012 Hip & Pelvis Roundup³⁶⁰ looks at: diagnosing the infected hip replacement; whether tranexamic acid has a low complication rate; the relationship between poor cementing technique and early failure of resurfacing; debridement and retention for the infected replacement; triple-tapered stems and bone mineral density; how early discharge can be bad for your sleep; an updated QFracture algorithm to predict the risk of an osteoporotic fracture; and local infiltration analgesia and total hip replacement.

Stems improve the mechanical stability of tibial components in total knee replacement (TKR), but come at a cost of stress shielding along their length. Their advantages include resistance to shear, reduced tibial lift-off and increased stability by reducing micromotion. Longer stems may have disadvantages including stress shielding along the length of the stem with associated reduction in bone density and a theoretical risk of subsidence and loosening, peri-prosthetic fracture and end-of-stem pain. These features make long stems unattractive in the primary TKR setting, but often desirable in revision surgery with bone loss and instability. In the revision scenario, stems are beneficial in order to convey structural stability to the construct and protect the reconstruction of bony defects. Cemented and uncemented long stemmed implants have different roles depending on the nature of the bone loss involved.

This review discusses the biomechanics of the design of tibial components and stems to inform the selection of the component and the technique of implantation.

We evaluated the biomechanical properties of two different methods of fixation for unstable fractures of the proximal humerus. Biomechanical testing of the two groups, locking plate alone (LP), and locking plate with a fibular strut graft (LPSG), was performed using seven pairs of human cadaveric humeri. Cyclical loads between 10 N and 80 N at 5 Hz were applied for 1 000 000 cycles. Immediately after cycling, an increasing axial load was applied at a rate of displacement of 5 mm/min. The displacement of the construct, maximum failure load, stiffness and mode of failure were compared.

The displacement was significantly less in the LPSG group than in the LP group (p = 0.031). All maximum failure loads and measures of stiffness in the LPSG group were significantly higher than those in the LP group (p = 0.024 and p = 0.035, respectively). In the LP group, varus collapse and plate bending were seen. In the LPSG group, the humeral head cut out and the fibular strut grafts fractured. No broken plates or screws were seen in either group.

We conclude that strut graft augmentation significantly increases both the maximum failure load and the initial stiffness of this construct compared with a locking plate alone.

We investigated the safety and efficacy of treating osteoporotic vertebral compression fractures with an intravertebral cleft by balloon kyphoplasty. Our study included 27 patients who were treated in this way. The mean follow-up was 38.2 months (24 to 54). The anterior and middle heights of the vertebral body and the kyphotic angle were measured on standing lateral radiographs before surgery, one day after surgery, and at final follow-up. Leakage of cement was determined by CT scans. A visual analogue scale and the Oswestry disability index were chosen to evaluate pain and functional activity. Statistically significant improvements were found between the pre- and post-operative assessments (p < 0.05) but not between the post-operative and final follow-up assessments (p > 0.05). Asymptomatic leakage of cement into the paravertebral vein occurred in one patient, as did leakage into the intervertebral disc in another patient.

We suggest that balloon kyphoplasty is a safe and effective minimally invasive procedure for the treatment of osteoporotic vertebral compression fractures with an intravertebral cleft.

Medial open-wedge high tibial osteotomy has been gaining popularity in recent years, but adequate supporting material is required in the osteotomy gap for early weight-bearing and rapid union. The purpose of this study was to investigate whether the implantation of a polycaprolactone-tricalcium phosphate composite scaffold wedge would enhance healing of the osteotomy in a micro pig model. We carried out open-wedge high tibial osteotomies in 12 micro pigs aged from 12 to 16 months. A scaffold wedge was inserted into six of the osteotomies while the other six were left open. Bone healing was evaluated after three and six months using plain radiographs, CT scans, measurement of the bone mineral density and histological examination.

Complete bone union was obtained at six months in both groups. There was no collapse at the osteotomy site, loss of correction or failure of fixation in either group. Staining with haematoxylin and eosin demonstrated that there was infiltration of new bone tissue into the macropores and along the periphery of the implanted scaffold in the scaffold group. The CT scans and measurement of the bone mineral density showed that at six months specimens in the scaffold group had a higher bone mineral density than in the control group, although the implantation of the polycaprolactone-tricalcium phosphate composite scaffold wedge did not enhance healing of the osteotomy.

The aim of this study was to determine the comorbid risk factors for failure in young patients who undergo fixation of a displaced fracture of the femoral neck. We identified from a prospective database all such patients ≤ 60 years of age treated with reduction and internal fixation. The main outcome measures were union, failure of fixation, nonunion and the development of avascular necrosis.

There were 122 patients in the study. Union occurred in 83 patients (68%) at a mean follow-up of 58 months (18 to 155). Complications occurred in 39 patients (32%) at a mean of 11 months (0.5 to 39). The rate of nonunion was 7.4% (n = 9) and of avascular necrosis was 11.5% (n = 14). Failures were more common in patients over 40 years of age (p = 0.03). Univariate analysis identified that delay in time to fixation (> 24 hours), alcohol excess and pre-existing renal, liver or respiratory disease were all predictive of failure (all p < 0.05). Of these, alcohol excess, renal disease and respiratory disease were most predictive of failure on multivariate analysis.

Younger patients with fractures of the femoral neck should be carefully evaluated for comorbidities that increase the risk of failure after reduction and fixation. In patients with a history of alcohol abuse, renal or respiratory disease, arthroplasty should be considered as an alternative treatment.

Low bone mass and osteopenia have been described in the axial and peripheral skeleton of patients with adolescent idiopathic scoliosis (AIS). Recently, many studies have shown that gene polymorphism is related to osteoporosis. However, no studies have linked the association between IL6 gene polymorphism and bone mass in AIS. This study examined the association between bone mass and IL6 gene polymorphism in 198 girls with AIS. The polymorphisms of IL6-597 G→A, IL6-572 G→C and IL6-174 G→A and the bone mineral density in the lumbar spine and femoral neck were analysed and compared with their levels in healthy controls. The mean bone mineral density at both sites in patients with AIS was decreased compared with controls (p = 0.0022 and p = 0.0013, respectively). Comparison of genotype frequencies between AIS and healthy controls revealed a statistically significant difference in IL6-572 G→C polymorphism (p = 0.0305). There was a significant association between the IL6-572 G→C polymorphism and bone mineral density in the lumbar spine, with the CC genotype significantly higher with the GC (p = 0.0124) or GG (p = 0.0066) genotypes.

These results suggest that the IL6-572 G→C polymorphism is associated with bone mineral density in the lumbar spine in Korean girls with AIS.