Hip resurfacing arthroplasty is an established and effective intervention for osteoarthritis of the hip in the young active patient, relying on the principle of femoral bone-stock preservation. A recognised mode of failure is neck thinning leading to radiological evidence of neck collapse and clinical failure. We report on a series of these slow-neck-failure patients and highlight the increased incidence of this phenomenon in post-menopausal female patients. This is a single operator, single implant series; 172 cases were identified from databases at our institution. 76 were female, mean (SD) age 52 (7) years. 96 were male, mean (SD) age 51(12) years. 15 (8.7%) patients required revision. 12 (80%) were female, 9 (75%) of these were due to slow neck failure. In the men one patient developed ALVAL requiring removal of his bilateral hip resurfacings, the other failure mode was early femoral neck failure. Mean time to failure was 6 months in men and 37 months in women. This difference in failure rates is also seen in the NJR figures. This review confirms the relatively high incidence of premature failure in post-menopausal females. NICE guidance in 2003, currently under review, stated that resurfacing is indicated in male patients up to 65 and female patients up to 60. As a result of this study we are currently advising post-menopausal patients that this risk of early failure may make total hip replacement a preferable option to resurfacing arthroplasty

Management of highly displaced acromioclavicular joint (ACJ) injuries remain contentious. It is unclear if delayed versus acute reconstruction has an increased risk of fixation failure and complications. The primary aim of this was to compare complications of early versus delayed reconstruction. The secondary aim was to determine modes of failure of ACJ reconstruction requiring revision surgery. A retrospective study was performed of all patients who underwent operative reconstruction of ACJ injuries over a 10-year period (Rockwood III-V). Reconstruction was classed as early (<12 weeks from injury) or delayed (≥12 weeks). Patient demographics, fixation method and post-operative complications were noted, with one-year follow-up a minimum requirement for inclusion. Fixation failure was defined as loss of reduction requiring revision surgery. 104 patients were analysed (n=60 early and n=44 delayed). Mean age was 42.0 (SD 11.2, 17–70 years), 84.6% male and 16/104 were smokers. No difference was observed between fixation failure (p=0.39) or deep infection (p=0.13) with regards to acute versus delayed reconstruction. No patient demographic or timing of surgery was predictive of fixation failure on regression modelling. Overall, eleven patients underwent revision surgery for loss of reduction and implant failure (n=5 suture fatigue, n=2 endo-button escape, n=2 coracoid stress fracture and n=2 deep infection). This study suggests that delayed ACJ reconstruction does not have a higher incidence of fixation failure or major complications compared to acute reconstruction. For those patients with ongoing pain and instability following a trial of non-operative treatment, delayed reconstruction would appear to be a safe treatment approach

The UK falls behind other European countries in the early detection of Developmental Dysplasia of the hip (DDH) and there remains controversy surrounding screening strategies for early detection. Clinical detection of DDH is challenging and recognised to be dependent on examiner experience. No studies exist assessing the number of personnel currently involved in such assessments.

Our objective was to study the current screening procedure by studying a cohort of new-born babies in one teaching hospital and assess the number of health professionals involved in neonatal hip assessment and the number of examinations undertaken during one period by each individual.

This was a retrospective observational study assessing all babies born consecutively over a 14-week period in 2020. Record of each initial baby check was obtained from Maternity or Neonatal Badger. Follow-up data on ultrasound or orthopaedic outpatient referrals were obtained from clinical records.

1037 babies were examined by 65 individual examiners representing 9 different healthcare professional groups. The range of examinations conducted per examiner was 1- 97 with a mean of 15.9 examinations per person. 49% individuals examined 5 or less babies across the 14 weeks, with 18% only performing 1 examination. Of the 5 babies (0.48%) treated for DDH, one was picked up on neonatal assessment.

In a system where so many examiners are involved in neonatal hip assessment the experience is limited for most examiners. It is unsurprising that high current rates of late presentation of DDH are observed locally, which are in accordance with published national experience.

Lateral-entry wiring (LEW) for displaced supracondylar humeral fractures (SHFs) has been popularised internationally. BOAST guidance suggests either LEW or crossed wires; the latter has reported lower risk of loss of fracture reduction –we explore technical reasons why.

We reviewed 8 years of displaced SHFs in two regional centres. Injuries were grouped using the Gartland Classification, with posterolateral or posteromedial displacement assessment for Gartland 3 injuries. We identified any loss of fracture reduction, and reviewed intra-operative imaging to identify learning points that may contribute to early rotational displacement (ERD).

345 SHFs were included, between 2012 and 2020. Gartland 2 (n=117) injuries had a 3.42% risk. ERD. Gartland 3 crossed wirings (n=114) had a 6.14% risk of ERD, with those moving all being posterolaterally displaced. Gartland 3, posterolaterally displaced LEW (n=56) had a 35.7% risk of ERD. Gartland 3, posteromedially displaced LEW (n=58) had a 22.4% risk of ERD. All injuries with ERD except 3 had identifiable learning points, the commonest being non-divergence of wires, or wires not passing through both fracture fragments.

LEW requires divergent spread and bicolumnar fixation. Achieving a solid construct through this method appears more challenging than crossed wiring, with rates of ERD 3–5× higher. Low-volume surgeons should adhere to BOAST guidelines and choose a wiring construct that works best in their hands. They can also be reassured that should a loss of position occur, the risk of requirement for revision surgery is extremely low in our study (0.3%), and it is unlikely to affect long term outcomes.

Aims. We examined risk of developing acute renal failure and the associated mortality among patients aged > 65 years undergoing surgery for a fracture of the hip. Patients and Methods. We used medical databases to identify patients who underwent surgical treatment for a fracture of the hip in Northern Denmark between 2005 and 2011. Acute renal failure was classified as stage 1, 2 and 3 according to the Kidney Disease Improving Global Outcome criteria. We computed the risk of developing acute renal failure within five days after surgery with death as a competing risk, and the short-term (six to 30 days post-operatively) and long-term mortality (31 days to 365 days post-operatively). We calculated adjusted hazard ratios (HRs) for death with 95% confidence intervals (CIs). Results. Among 13 529 patients who sustained a fracture of the hip, 1717 (12.7%) developed acute renal failure post-operatively, including 1218 (9.0%) with stage 1, 364 (2.7%) with stage 2, and 135 (1.0%) with stage 3 renal failure. The short-term mortality was 15.9% and 5.6% for patients with and without acute renal failure, respectively (HR 2.8, 95% CI 2.4 to 3.2). The long-term mortality was 25.0% and 18.3% for those with and without acute renal failure, respectively (HR 1.3, 95% CI 1.2 to 1.5). The mortality was higher in patients with an increased severity of renal failure. Conclusion. Acute renal failure is a common complication of surgery in elderly patients who sustain a fracture of the hip, and is associated with increased mortality up to one year after surgery despite adjustment for coexisting comorbidity and medication before surgery. Cite this article: Bone Joint J 2016;98-B:1112–18.

The aim of the study was to describe the failure rate of locking plates used for internal fixation of distal femoral fractures and to identify independent predictors of failure. A consecutive series of 147 patients presenting to the study unit during an 8 year period with a distal femoral fracture were identified from a prospectively compiled trauma database. There were 117 females and 30 males, with a mean age of 70.7 years (13 to 99 years), of which 77 were periprosthetic fractures and 70 were supracondylar fractures around native knees. There were 35 failures of fixation. The commonest cause was non-union (n=31). The survival of the plate 2 years post-surgery was 74percnt; (95percnt; CI 64percnt; to 84percnt;), which remained static to a mean follow of 5 years. There was no difference in failure of fixation according to gender (p=0.32) or if there was a periprosthetic fracture (p=0.8). Younger age (61.8 vs. 73.6 years, p=0.004), increasing level of comorbidity (p=0.02), and fracture comminution (p=0.001) were all significant predictors of failure of fixation. Cox regression analysis confirmed younger age (p=0.04), increasing comorbidity (p=0.002), and fracture comminution (p=0.002) as independent predictors of failure of fixation and non-union after adjusting for confounding. The failure of locking plates for distal femoral fractures occurs in more than one in five patients. The independent predictors could be used to identify those patients at greatest risk of failure of the locking plate, who may benefit from alternative methods of fixation, primary bone grafting, or interventions that may aid union

Aim. The aim of this study was to determine whether the absence of periosteal reaction on plain radiographs was predictive of exchange nail failure in lower limb diaphyseal fracture non-unions. Methods. A consecutive cohort of 20 femora and 35 tibiae undergoing exchange nailing for diaphyseal aseptic (n=39) and septic (n=16) fracture non-union at a single centre from 2003 to 2010. Multiple causes of non-union were found in 29 patients (53%) with infection present in 16 cases (29.1%). Of this cohort 49 fracture non-unions had complete radiographic records (19 femora and 30 tibiae) allowing evaluation of the periosteal callus. The primary outcome was the number of number of revision procedures required to achieve union. Failure was defined was as the requirement of >two revision procedures to achieve union. Results. The absence of periosteal callus from the fracture site on all four cortices conferred a relative risk ratio (RRR) 5.00 (p=0.006) of exchange nail failure in septic fracture non-unions. Receiver operator characteristic curve analysis of number of cortices with periosteal reaction for predicting exchange nail (>two exchange nail procedures) failure in both septic and aseptic cases found an area under the curve of 0.79 (95% confidence interval 0.675–0.904, p<0.0001). The complete absence of callus within 5 mm of the fracture site had a 75% chance of requiring 3 or more exchange nails to obtain union. Conversely the presence periosteal callus on at least one cortex within 5mm of the fracture site had a 100% chance the fracture would unite following 1 or 2 exchange nail procedures. Conclusion. Careful radiographic analysis of lower limb diaphyseal non-union should be undertaken before exchange nailing. The absence of periosteal reaction on plain radiographs in septic fracture non-union is predictive of exchange nail failure

The Gamma nail is frequently used in unstable peri-trochanteric hip fractures. We hypothesised that mechanical failure of the Gamma nail was associated with inadequate proximal three-point fixation. We identified a consecutive series of 299 Gamma nails implanted in 299 patients over a five-year period, 223 of whom fulfilled our inclusion criteria for investigation. The series included 61 men and 162 women with a mean age of 81 years (20 to 101). Their fractures were classified according to the Modified Evans’ classification and the quality of fracture reduction was graded. The technical adequacy of three points of proximal fixation was recorded from intra-operative fluoroscopic images, and technical inadequacy for each point was defined. All patients were followed to final follow-up and mechanical failures were identified. A multivariate statistical analysis was performed, adjusting for confounders. A total of 16 failures (7.2%) were identified. The position of the lag screw relative to the lateral cortex was the most important point of proximal fixation, and when inadequate the failure rate was 25.8% (eight of 31: odds ratio 7.5 (95% confidence interval 2.5 to 22.7), p < 0.001). Mechanical failure of the Gamma nail in peri-trochanteric femoral fractures is rare (< 1%) when three-point proximal fixation is achieved. However, when proximal fixation is inadequate, failure rates increase. The strongest predictor of failure is positioning the lateral end of the lag screw short of the lateral cortex. Adherence to simple technical points minimises the risk of fixation failure in this vulnerable patient group. Cite this article: Bone Joint J 2013;95-B:825–30

Background. Unicompartmental knee arthroplasty provides a good alternative to total knee arthroplasty in patients with isolated medial compartment osteoarthritis. There has been variable reporting in the literature as to whether age and sex affect the survival of unicompartmental knee arthroplasty. The aim of this study was to determine whether age and sex were predictors of failure for the Oxford unicompartmental knee arthroplasty. Methods. Details of consecutive patients undergoing Oxford unicompartmental knee arthroplasty at our centre between January 2000 and December 2009 were collected prospectively. Failure of the implant was defined as conversion to total knee arthroplasty. Survival was determined using the Kaplan-Meier method. A Cox proportional hazard model was used to determine the affect of age and sex on survivorship of the prosthesis. Results. There were 494 Oxford unicompartmental knee arthroplasties implanted in 425 patients for isolated medial compartment osteoarthritis. Mean age was 62.8 yr (range 34.6–90.1 yr) and 53.4% were female. During a mean follow-up time of 3.0 yr (range 0.5–9.2 yr), twenty-two knees (4.5%) were revised to a total knee arthroplasty with an 8-year survival for the cohort of 87.4%. Age had a statistically significant impact on survival (p=0.018), with increasing age associated with improved survival of the prosthesis. Sex was not demonstrated to be a statistically significant predictor of failure. Discussion. Our findings demonstrate that decreasing age was a predictor of failure of the Oxford unicompartmental knee arthroplasty, but sex had no impact on failure of the prosthesis. It is therefore recommended that age should be taken into account when younger patients are being considered for Oxford unicompartmental knee arthroplasty. In addition, preoperatively patients should be counselled appropriately regarding the increased risk of revision surgery

Background. A number of studies have reported on the early failure of the Oxford unicompartmental knee arthroplasty. However, less evidence is available regarding the outcome following revision of failed unicompartmental knee prostheses to total knee arthroplasty. The aims of this study were to determine the time to failure for the Oxford unicompartmental knee arthroplasty and to assess the short-term outcome following revision surgery. Methods. Details of consecutive patients undergoing revision of an Oxford unicompartmental knee arthroplasty to a total knee arthroplasty at our centre between January 2000 and December 2009 were collected prospectively. Data was collected on patient demographics, indication for revision surgery, and time to revision from the index procedure. Clinical and radiological outcome following revision arthroplasty was also assessed. Results. During the study period 22 (4.5%) of 494 Oxford unicompartmental knee arthroplasties were revised to a total knee arthroplasty. Mean age at the time of revision surgery was 61.8 yr and 13 (59%) patients were male. Mean time to revision surgery from the primary procedure was 3.0 yr (range 0.6–6.2 yr). The commonest reasons for revision were aseptic loosening of the femoral (n=9) or tibial component (n=2), and undiagnosed (n=5) or patellofemoral pain (n=2). All patients were revised to a cemented total knee arthroplasty with most not requiring bone grafts. During follow-up (range 0.5–4.5 yr) no further surgery was performed in the 22 patients. In addition, there were no major postoperative complications and no evidence of radiological failure. Discussion. The present study demonstrates most failures of the Oxford unicompartmental knee arthroplasty occur within three to four years following the index procedure and are due to aseptic component loosening. These findings are consistent with other published reports regarding the early failure of this particular prosthesis. The short-term outcome following revision surgery appears to be good, however longer follow-up periods are required to determine if these good results continue

Background. The treatment of femoral neck fracture with internal fixation (IF) is recommended in younger patients and has compared to arthroplasty the advantage of retaining the femoral head. A big problem with osteosynthesis is though failure. Finding predictors for fixation failure is still an ongoing process and osteoporosis has been suggested as a predictor. Aim. To correlate bone mineral density (BMD) in regard to failure of IF in osteosynthesized femoral neck fractures. Material and method. In a health technology assessment study from 2005–2006 at Odense University Hospital, Department of Orthopaedic Surgery and Traumatology, 175 patients with femoral neck fractures accepted DEXA - scanning of the hip and lumbar spine assessing BMD. Final follow-up were 01.08.2010 and 141 patients with IF comprised the final cohort. The cohort consisted of 105 females and 36 males with a mean (CI) age of 77,2 (75,4–79,0). Failure is defined as revision surgery or new fracture. Results. 69 patients had a t-score (total hip) below −2,5 SD as defined for osteoporosis. At 1 year the overall (dislocated) failure rate was 34,5 % (44,7 %), at 2 years 45,4 % (60,0 %) and at end of follow-up 49,6 % (62,8 %). In the cox regression analysis the following factors for failure were significant: dislocated fracture, osteosynthesis placement and prior fracture. There were no associations for total hip BMD, neck BMD, age, sex, quality of fracture reduction, walking disability, independent living, alcohol or smoking. A cox regression sub analysis of the undisplaced fractures showed significant result only for osteosynthesis placement. Conclusion. There is no association between BMD and failure of internal fixation in osteosynthesized femoral neck fractures

The aim of this study was to identify risk factors for failure of exchange nailing in tibial diaphyseal fracture non-unions. The cohort comprised 99 tibial diaphyseal fracture non-unions treated by exchange nailing. The mean age of the patients at exchange nail surgery was 36 years. The median time from primary fixation to exchange nailing was 6.4 months. The main outcome measures were union, number of secondary fixation procedures required to achieve union and time to union. Univariate analysis and multiple regression were used to identify risk factors for failure to achieve union. Multiple causes for non-union were found in 31.3% cases, with infection present in 32.3%. Further exchange procedures were required in 35.4%, 7.1% required the use of other fixation modalities. Union was ultimately achieved in 97.8%. The median time to union was 8.7 months. Univariate analysis revealed that cigarette smoking, an atrophic pattern of non-union and infection were predictive for failure of exchange nailing (p<0.05). Multi-regression analysis found that only infection was statistically significantly predictive (p<0.05) of exchange nail failure. Exchange nailing is an effective treatment for tibial diaphyseal non-unions even in the presence of infection. Smoking, atrophic pattern of non-union and infection are associated with an increased risk of further fixation surgery

Aims. Fractures of the distal femur can be challenging to manage and are on the increase in the elderly osteoporotic population. Management with casting or bracing can unacceptably limit a patient’s ability to bear weight, but historically, operative fixation has been associated with a high rate of re-operation. In this study, we describe the outcomes of fixation using modern implants within a strategy of early return to function. Patients and Methods. All patients treated at our centre with lateral distal femoral locking plates (LDFLP) between 2009 and 2014 were identified. Fracture classification and operative information including weight-bearing status, rates of union, re-operation, failure of implants and mortality rate, were recorded. Results. A total of 127 fractures were identified in 122 patients. The mean age was 72.8 years (16 to 101) and 92 of the patients (75%) were female. A consultant performed the operation in 85 of the cases, (67%) with the remainder performed under direct consultant supervision. In total 107 patients (84%) were allowed to bear full weight immediately. The rate of clinical and radiological union was 81/85 (95%) and only four fractures of 127 (3%) fractures required re-operation for failure of surgery. The 30-day, three- and 12-month mortality rates were 6 (5%), 17 (15%) and 25 (22%), respectively. Conclusion. Our study suggests an exponential increase in the incidence of a fracture of the distal femur with age, analogous to the population suffering from a proximal femoral fracture. Allowing immediate unrestricted weight-bearing after LDFLP fixation in these elderly patients was not associated with failure of fixation. There was a high rate of union and low rate of re-operation. Cite this article: Bone Joint J 2017;99-B:951–7

The Oxford medial unicompartmental knee replacement has been shown to provide good long-tern results in numerous studies with survivorship at 10 years ranging from 82% to 100%. This prospective study describes the survival of 265 Oxford unicompartmental knee replacements implanted in one centre from 1995-2009. 8 were lost to follow up. 40 of the 265 knees were revised. For operation performed from1995-1999 the risk of revision at 5 years was 10%, operations from 2000-2004 the risk of revision was 15% and from 2005-2009 the risk of revision at 5 years was 36%. This study demonstrates that since 2005 there has been a significant increase in early failure of the Oxford unicompartmental knee at this institution and discusses the possible reasons for this

Aims. Our aim in this study was to describe the long-term survival of the native hip joint after open reduction and internal fixation of a displaced fracture of the acetabulum. We also present long-term clinical outcomes and risk factors associated with a poor outcome. Patients and Methods. A total of 285 patients underwent surgery for a displaced acetabular fracture between 1993 and 2005. For the survival analysis 253 were included, there were 197 men and 56 women with a mean age of 42 years (12 to 78). The mean follow-up of 11 years (1 to 20) was identified from our pelvic fracture registry. There were 99 elementary and 154 associated fracture types. For the long-term clinical follow-up, 192 patients with complete data were included. Their mean age was 40 years (13 to 78) with a mean follow-up of 12 years (5 to 20). Injury to the femoral head and acetabular impaction were assessed with CT scans and patients with an ipsilateral fracture of the femoral head were excluded. Results. A total of 36 patients underwent total hip arthroplasty (THA). The overall ten-year survival of the hip joint was 86% (95% confidence interval (CI) 81% to 90%) and the 20-year survival was 82% (95% CI 76% to 87%). Injury to the femoral head and acetabular impaction were the strongest predictors of failure, with the long-term survival rate falling towards 50% in these patients. The survival fell to 0% at three years when both these risk factors were present in patients aged > 60 years. Conclusion. The long-term survival of the native hip joint after acetabular fractures was good, but the presence of injury to the femoral head and acetabular impaction proved to be strong predictors of failure, especially in patients aged > 60 years. These patients may be better treated with a combination of open reduction and internal fixation and primary arthroplasty. Cite this article: Bone Joint J 2017;99-B:834–40

Early failure of metal-on-metal (MoM) total hip replacements (THR) is now well established. We review 93 consecutive patients with CPT¯ stems MoM THR. Our series demonstrates a new mechanism of failure, which may be implant combination specific. Between January 2005 and June 2009, 93 consecutive MoM total hip replacements were preformed using CPT stems by 3 surgeons at our unit. 73 CPT¯ stems, Metasul¯ Large Diameter Heads (LDH) with Durom¯ acetabulae and 20 CPT¯ stems, Metasul¯ 28mm diameter heads in Allofit¯ shells (zimmer). Clinical outcomes were collected prospectively before surgery, at 3 months, 1 year, 2 years, 3 years, and at 5 years post surgery. Revision for any cause was taken as the primary endpoint and the roentgenograms and explanted prostheses were analyzed for failure patterns. In the LDH/Durom¯ group a total of 13 (18%) patients required revision (figs. 1) at a median of 35 months (range 6-44). 6 (8%) for periprosthetic fracture. All 6 periprostethic fractures were associated with minimal or no trauma and all had ALVAL identified histologically. To date there have been no failures in the CPT¯/28mm head Allofit¯ group. Several failures demonstrated bone loss in Gruen zones 8 ± 9 ± 10 (fig. 2). We demonstrate an unacceptably high rate of failure in CPT¯ MoM LDH hip replacements, with a high failure secondary to periprosthetic fracture and postulate a mechanism associated with local toxicity to metal ions. We strongly advise against this combination of prosthesis

Unicompartmental knee replacements (UKRs) have inconsistent and variable survivorships reported in the literature. It has been suggested that many are revised for ongoing pain with no other mode of failure identified. Using a medial UKR with an all-polyethylene non-congruent tibial component from 2004–7, we noted a revision rate of 9/98 cases (9.2%) at a mean of 39 months. Subchondral sclerosis was noted under the tibial component in 3/9 revisions with well fixed implants, and the aim of this study was to investigate this as a mode of failure. 89 UKRs in 77 patients were investigated radiographically (at mean 50 months) and with SF-12 and Oxford Knee scores at mean follow up 55 months. Subjectively 23/89 cases (25%) had sclerosis under the tibial component. We describe a method of quantifying this sclerosis as a greyscale ratio (GSR), which was significantly correlated with presence/absence of sclerosis (p<0.001). Significant predictors of elevated GSR (increasing sclerosis) were female sex (p<0.001) and elevated BMI (P=0.010) on both univariate and multivariate analysis. In turn, elevated GSR was significantly associated with poorer improvement in OKS (p<0.05) at the time of final follow up. We hypothesise that this sclerosis results from repetitive microfracture and adaptive remodelling in the proximal tibia due to increased strain. Finite element analysis is required to investigate this further, but we suggest caution should be employed when considering all polyethylene UKR implants in older women and in those with BMI >35

Combined glenoid and humeral bone loss has been identified as an important factor in predicting recurrence after arthroscopic shoulder stabilisation. The “glenoid track” concept is proposed to predict recurrent instability by comparing the relative size of the glenoid to the humeral bone defect. The aim of this study was to investigate whether assessment of the glenoid track on a pre-operative MR arthrogram could be used to predict subsequent instability in a typical UK population.

A retrospective study was undertaken of 175 primary arthroscopic stabilisation procedures of which 82% (n=143) were men. The median age was 26 years (IQR 22 to 32, range 16 to 77). The median follow-up was 76 months (range 21 to 125). A pre-operative MR arthrogram was used to determine if the shoulder was on-track or off-track. The endpoint of recurrent dislocation was examined.

The prevalence of “off-track” bone loss in this group was 14.2% (n=25). There were 6 (24%) dislocations in the off-track group compared with 5 (3.33%) dislocations in the on-track group (RR 7.2, 95% CI 2.45 to 20.5, p=0.001). At 5 years, the cumulative redislocation rate was 26.1% in the off-track group compared with 8.7% in on-track group. The rate of any recurrent instability was 60% (n=15) v 18% (n=27) (RR 3.33, 95% CI 2.02 to 5.20, p<0.0001). Glenoid track (on v off) was not predicted by gender (p=0.411).

In a typical UK population assessment of the glenoid track on an MR arthrogram can be used to risk stratify patients with shoulder instability.

We reviewed 110 patients with an unstable fracture of the pelvic ring who had been treated with a trapezoidal external fixator after a mean follow-up of 4.1 years. There were eight open-book (type B1, B3-1) injuries, 62 lateral compression (type B2, B3-2) and 40 rotationally and vertically unstable (type C1-C3) injuries. The rate of complications was high with loss of reduction in 57%, malunion in 58%, nonunion in 5%, infection at the pin site in 24%, loosening of the pins in 2%, injury to the lateral femoral cutaneous nerve in 2%, and pressure sores in 3%. The external fixator failed to give and maintain a proper reduction in six of the eight open-book injuries, in 20 of the 62 lateral compression injuries, and in 38 of the 40 type-C injuries. Poor functional results were usually associated with failure of reduction and an unsatisfactory radiological appearance. In type-C injuries more than 10 mm of residual vertical displacement of the injury to the posterior pelvic ring was significantly related to poor outcome. In 14 patients in this unsatisfactory group poor functional results were also affected by associated nerve injuries. In lateral compression injuries the degree of displacement of fractures of the pubic rami caused by internal rotation of the hemipelvis was an important prognostic factor. External fixation may be useful in the acute phase of resuscitation but it is of limited value in the definitive treatment of an unstable type-C injury and in type-B open-book injuries. It is usually unnecessary in minimally displaced lateral compression injuries

Introduction. Periprosthetic femur fractures are a serious complication after hip replacement surgery. In an aging population these fractures are becoming more and more common. Open reduction and plate osteosynthesis is one of the available treatment options. Objective. To investigate hip stem stability and cement mantle integrity under cyclic loading conditions after plate fixation with screws perforating the cement in the proximal fragment. Methods. Polished tapered hip stems were implanted in 16 biomechanical testing femora with Palacos cement (3rd generation technique) according to the manufacturer's recommendations. 8 testing bones were osteotomised distal to the stem representing the fracture group (Vancouver Type C). The osteotomy was fixed with a polyaxial locking plate, the other 8 specimens served as a control group. The specimens were tested in a biaxial material testing machine under axial compression (including adduction and torsion moments) for 100.000 cycles at physiological loads. Stem subsidence was measured in 3 planes with a stereoscopic image correlation system during the tests. Subsequently the sliced and crack dyed specimens were investigated microscopically for cement cracks. Results. In the control group no specimen failed during testing. There were no statistically significant differences in stem subsidence along the longitudinal axis (control group mean ± SD −15.4 ± 12.2 μm, fracture group −14.1 ± 13.1 μm). In the fracture group two specimens fractured through the most proximal screw hole after 74.000 and 80.000 cycles. Overall 15 out of 36 screws in the proximal fragment had direct stem contact. No cement cracks were detected in the sliced specimens in both groups. Conclusion. Drilling the cement mantle and placing screws in the cement did not increase stem subsidence under cyclic loading. No cracks or cement mantle failure were observed. Large screw diameters proximally weaken the lateral cortex resulting in tension failure of the bone. Plate fixation of a periprosthetic femoral fracture with a stable, cemented prosthesis does not lead to early cement mantle failure