Objectives. In order to address acetabular defects, porous metal revision acetabular components and augments have been developed, which require fixation to each other. The fixation technique that results in the smallest relative movement between the components, as well as its influence on the primary stability with the host bone, have not previously been determined. Methods. A total of 18 composite hemipelvises with a Paprosky IIB defect were implanted using a porous titanium 56 mm multihole acetabular component and 1 cm augment. Each acetabular component and augment was affixed to the bone using two screws, while the method of fixation between the acetabular component and augment varied for the three groups of six hemipelvises: group S, screw fixation only; group SC, screw plus cement fixation; group C, cement fixation only. The implanted hemipelvises were cyclically loaded to three different loading maxima (0.5 kN, 0.9 kN, and 1.8 kN). Results. Screw fixation alone resulted in up to three times more movement (p = 0.006), especially when load was increased to 100% (p < 0.001), than with the other two fixation methods (C and SC). No significant difference was noted when a screw was added to the cement fixation. Increased load resulted in increased relative movement between the interfaces in all fixation methods (p < 0.001). Conclusion. Cement fixation between a porous titanium acetabular component and augment is associated with less relative movement than screw fixation alone for all implant interfaces, particularly with increasing loads. Adding a screw to the cement fixation did not offer any significant advantage. These results also show that the stability of the tested acetabular component/augment interface affects the stability of the construct that is affixed to the bone. Cite this article: N. A. Beckmann, R. G. Bitsch, M. Gondan, M. Schonhoff, S. Jaeger. Comparison of the stability of three fixation techniques between porous metal acetabular components and augments. Bone Joint Res 2018;7:282–288. DOI: 10.1302/2046-3758.74.BJR-2017-0198.R1

Introduction

When designing a new osteosynthesis device, the biomechanical competence must be evaluated with respect to the acting loads. In a previous study, the loads on the proximal phalanx during rehabilitation exercises were calculated. This study aimed to assess the safety of a novel customizable osteosynthesis device compared to those loads to determine when failure would occur.

Introduction: The introduction of bioabsorbable materials has improved the ability to offer a simple, fast and friendly user solution, to specific meniscal tears. The technique of meniscal suture with bioabsorbable tacks is associated with lower morbidity and lower complication rate. Methods: Between 1997 and 2004, 14 patients underwent arthroscopic all-inside meniscus repair. We used Biofix bioabsorbable tacks fixation technique. Fourteen patients were followed-up: 11 males and 3 females. Their mean age was ~23 years (range 16–34). Follow-up average ~35 (range 6–72) months. Sport injuries were the main cause of meniscal tears (60%). Other causes included: work accidents (20%) and military accidents (20%). All the tears were located in red-on-red and red-on-white area. The mean length of tear was 9.6 mm. we used in average 2.5 tacks per meniscus tear. Furthermore, 4 patients had an associated ACL tear. Results: The evaluation was based on Lisholm score. The results were excellent in 10 patients (71%), good in 1 patient (7%), fair in 2 patients (15%) and poor in 1 patient (7%). One patient suffered from transitory tender point on the medial aspect due to a protruded tack. One patient needed a menisectomy due to unresolved symptoms. One patient underwent ACL reconstruction. Conclusion: This technique is an easy and reproducible procedure as compared to the classical meniscal suture techniques. It seems to be of a lower complication rate and further studies are needed to establish any associated morbidity

Introduction: The complex anatomy and biomechanics of the atlantoaxial motion segment impose technical challenges in the achievement of safe and successful surgical stabilization and fusion. The coauthors have recently reported successful clinical results using a novel C1-C2 stabilization technique employing C1 multi-axial posterior arch screws (MA-PAS). This study compares biomechanical stability of MA-PAS with two established multi-point fixation techniques (Magerl-Gallie and Harms) using non-destructive and destructive testing. Methods: 15 human fresh-frozen cadaveric occipital-C5 cervical spines (average age 77.4 [51–95], sourced from ScienceCare, USA) were randomly allocated to 3 equal groups. Screws were passed up through adjacent end vertebrae such that motion was limited to between C0 and C4. Each spinal column was non-destructively tested in flexion/extension (±1.5Nm), lateral bend (±1.5Nm) and axial rotation (±1.5Nm), firstly in their INTACT state and then after Type 2 odontoid fracture destabilization combined with MAGERL-GALLIE (n=5), HARMS (n=5) or MA-PAS (n=5) instrumentation. All 15 reconstructed spines were finally loaded to failure in forward flexion only. Results: Non-destructive testing: The C1-C2 joint of the INTACT spines all demonstrated high flexibility in flexion/ extension (ave 16.5deg) and axial rotation (ave 52.6 deg) while lateral bending (ave 2.7deg) was less compliant (see Fig.3). After instrumentation all specimens showed significantly reduced ROM in flexion/extension (MAGERL-GALLIE=4.2deg, HARMS=4.4deg, MA-PAS=4.2deg) and axial rotation (MAGERL-GALLIE=4.05deg, HARMS=0.59deg, MA-PAS=3.7deg) while lateral bend ROM of all instrumented specimens was similar or slightly greater than INTACT (HARMS=2.3deg, MAGERL-GALLIE=3.8deg, MA-PAS=5.3deg). There was no significant difference between the instrumented groups in each loading direction. Destructive testing: MAGERL-GALLIE was the strongest requiring an average of 13.5Nm to cause failure while HARMS was the weakest requiring 7.8Nm of torque. MA-PAS technique averaged 12.2Nm of torque to cause failure. Conclusions: The MA-PAS technique was shown to have similar ultimate strength in flexion to the MAGERL-GALLIE and HARMS techniques and stability in flexion-extension, axial rotation and lateral bend. The MA-PAS failure load in flexion was greater than the HARMS technique, and nearly as high as the MAGERL-GALLIE. Given the biomechanical stability of the MA-PAS technique, it is proposed that this technique is an alternative to the technically demanding, and possibly more hazardous, conventional multi-point fixation techniques in patients with normal, as well as anomalous, C1/2 segmental anatomy

Existing techniques of posterior multi-point C1/2 stabilisation are technically demanding and can be hazardous. The coauthors have recently reported successful atlantoaxial fusion using a novel C1/2 stabilisation technique employing C1 multi-axial posterior arch screws (MA-PAS) in a clinical series of three patients where anatomical anomalies precluded established techniques. The technically less demanding nature of this new technique, and possible wider application in patients with normal anatomy, led the authors to investigate its biomechanical stability compared to other established techniques. Twenty-four human fresh-frozen cadaveric spines were harvested C0-C5. Motion was restricted to between C0 and C4. Each spine was non-destructively tested in flexion/extension, lateral bending and axial rotation, firstly in the intact state and then after Type 2 odontoid fracture destabilisation and insertion of Magerl-Gallie, Unicortical Harms, Bicortical Harms or MA-PAS instrumentation. ROM between C1 and C2 was monitored using two digital cameras. Results for each technique were compared statistically compared using ANOVA. The C1-C2 joint of the intact spines demonstrated high flexibility in flexion/extension (16.5deg). After instrumentation all specimens showed significantly reduced ROM in flexion/extension (Magerl-Gallie FE = 4.2deg, Unicort Harms FE = 7.2deg, Bicort Harms FE = 4.4deg). Lateral bend ROM of instrumented specimens (Magerl-Gallie LB =3.8deg, Unicort Harms LB = 3.8deg, Bicort Harms LB =2.3 deg) was, however, similar or slightly greater than intact (2.7 deg) . MA-PAS showed similar ROM in flexion/extension (4.2 deg) as the Magerl-Gallie and Harms techniques but was slightly higher in lateral bend (5.3 deg). The MA-PAS technique was shown to have similar biomechanical stability to the Magerl-Gallie and Harms techniques. Given the demonstrated biomechanical stability of the MA-PAS technique, it may be a suitable alternative to the existing technically demanding, and possibly more hazardous, multi-point fixation techniques in patients with normal, as well as anomalous, C1/2 segmental anatomy

Anatomic reduction (subcapital re-alignment osteotomy) via surgical hip dislocation – increasingly popular. While the reported AVN rates are very low, experiences seem to differ greatly between centres. We present our early experience with the first 29 primary cases and a modified fixation technique. We modified the fixation from threaded Steinman pins to cannulated 6.5mm fully-threaded screws: retrograde guidewire placement before reduction of the head ensured an even spread in the femoral neck and head. The mean PSA (posterior slip angle) at presentation (between 12/2008 and 01/2011) was overall 68° (45–90°). 59% (17/29) were stable slips (mean PSA 68°), and 41% (12/29) were unstable slips unable to mobilise (mean PSA 67°). The vascularity of the femoral head was assessed postoperatively with a bone scan including tomography. The slip angle was corrected to a mean PSA of 5.8° (7° anteversion to 25° PSA). We encountered no complications related to our modified fixation technique. All cases with a well vascularised femoral head on the post-operative bone scan (15/17 stable slips and 8/12 unstable slips) healed with excellent short term results. Both stable slips with decreased vascularity on bone scan (2/17, 12%) had been longstanding severe slips with retrospectively suspected partial closure of the physis, which has been described as a factor for increased risk of avascular necrosis (AVN). One of these cases was complicated by a posterior redislocation due to acetabular deficiency. In the unstable group, 4/12 cases (33%) had avascular heads intra-operatively and cold postoperative bone scans, 3 have progressed to AVN and collapse. Anatomic reduction while sparing the blood supply of the femoral head is a promising concept with excellent short term results in most stable and many unstable SCFE cases. Extra vigilance for closed/closing physes in longstanding severe cases seems advisable. Regardless of treatment, some unstable cases inevitably go on to AVN

Distal radial fractures represent 17% of fractures in the Italian E.R. In the last years many different techniques accompanied the traditional treatment of closed reduction and cast immobilization such as closed reduction + pinning + cast, “epi-block” fixation, ORIF with dorsal and/or volar plates, screws and external fixation. These techniques are mostly followed by a period of immobilization with cast which is optional in A.O. type A fractures and is usually necessary in type B and C fractures. At the University Hospital “Policlinico Umberto I” of Rome E.R. we have started treating these fractures with a new fixation system which we projected. This system provides a non-bridging external fixation. The synthesis is guaranteed by two or more K-wires which can be intramedullary or x-crossing the cortex and/or inter-fragmentary. These K-wires are connected with two radial pins by an external bar. This radial to radial system gives stability to the fracture and allows the patient to move the wrist immediately. We remove this fixation system after 40 days. From July 2008 to August 2009 we treated 56 distal radial fractures. Clinical assessment was performed every seven days until removal of external fixation system, then at 2, 3, 6 and 12 months. Radiographic assessment was performed at 30 and 40 days, consequently at 2, 3, 6 and 12 months. Outcome was measured on the basis of range of motion, grip and pinch strength, DASH and PRWE scores. A questionnaire was used to determine patient satisfaction, and a detailed analysis of complications was carried out. All patients had excellent or good results and were satisfied with the clinical outcome. At 60 days after surgery 90% of patients demonstrated complete clinical and functional recovery. After 3 months 100% of patients demonstrated complete clinical and functional recovery. After 6 months and 12 months no modification of the obtained result was detected

In Displaced Intracapsular Hip Fractures (ICHF) in young active patients, preservation of the femoral head and its blood supply are of high importance and urgent surgical treatment with anatomic reduction and internal fixation is the preferred intervention. Due to the strong varus displacement shear forces exerted across the hip, there are relatively high complication rates after fixation. There is no consensus regarding the optimal fixation device or technique. This retrospective study compared closed reduction internal fixation method using cannulated cancellous screw (CCS) with the Targon Femoral Neck (TFN) hip fixed angle screw. Data regarding, gender, operational data, duration of surgery, complications, NAS (Numerical Analogue Scale) pain score, Modified Harris Hip Score (MHHS) and SF-12 scores were retrieved for patients younger than 65 with displaced ICHF. Eighty-two patients were included in the study, 30 patients treated with CCS were compared to 52 patients treated with TFN. Fracture configuration (Garden and Pauwel classifications), mean time to surgery and complication rate did not differ significantly. Operative time did differ significantly between groups (CCS 56 minutes, TFN 92 minutes, p<0.001). At final follow-up the CCS group reported less pain (NAS 2.3 vs 3.5, p< 0.049) and better Mental Health Composite score of SF-12 (p=0.017) compared to the TFN group. Complication rates for the treatment of displaced ICHF with TFN and CCS showed no significant differences; however, the functional outcomes, as presented by the NAS and Mental Health Composite score of SF-12, showed superiority for CCS treatment. As this fixation method is related to reduce costs, we suggest CCS for the treatment of displaced ICHF in the young population.

Introduction: Internal fixation of distal radius fractures with dorsal plates (when needed) comprise two potential problems: efficacy of stabilization and the high frequency of tendonitis which forced us to early removal of the hardware. Our purpose is to study the efficacy of the method of stabilization with 2 plates (2mm) the central and radial columns of distal radius according to the technique presented by Regazzoni (1993).

Material and Methods: Eight patients (5 males and 3 females), average 35 years old (range, 20–52 years) were treated with comminuted intraarticular fracture type C (6 patients) or malunion of distal radius (2 patients). A combined approach was used in 4 patients and only dorsal approach in the rest 4 patients. In all patients with recent comminuted fractures a supplementary fixation method with allograft were used. In patients with mal-united fractures the technique with two plates together with iliac graft were applied.

Results: Results estimated after mean follow-up of 14 months (range 9–18 months) according to clinical (pain, range of motion, and grip strength) and radiological (articular congruency, radial height, radial inclination and palmar tilt) criteria. Six patients revealed excellent or good result although two patients with loss of reduction needed a second operation.

Conclusion: We concluded, that when the technique with 2 plates was applied correctly the stability of fixation enhanced because the detrimental rotational forces were cancelled while the frequency of tendon irritation decreased.

Post operative stability is of paramount importance to obtain bone in growth and a tight interface in uncemented implants. Although hemispherical press fit cups are widely used different opinions exists according optimal fixation and a variety of principles are preferred. Lab studies show better stability if a cup is augmented by screws or pegs. However, cups with screws and holes increases penetration of joint fluid, pressure and particles to the interface with a risk for osteolyses. HA coating is in many studies favourable to obtain a quick in growth but is by many regarded unnecessary or even a risk for increased wear. This RSA studie was done to investigate stability and wear in cups with different fixation.

Material: 80 hips in 75 patients with a mean age of 58 years (36–70) were operated with a cemented Spectron stem and a porous coated Reflection cup of titanium (Smith a Nephew) All cups were oversized 1–2 mm and fixed with press fit by experienced surgeons. Great care was taken to achieve a good rim fit. They hips were by randomisation allocated to one of four groups with different fixation methods. One group was done with only press fit technique, one with additional screws, one additional pegs and another with HA coating on the porous surface. Migration and wear was investigated with RSA at 2, 12 and 24 months and standard radiography was done post op and at 2 years.

Mann-Whitneys U-test was used on signed values for evaluation of group differencies.

Results: At 2 years the mean cup migration for the whole group was 0.2 mm longitudinally, 0.3 mm horizontally and 0.3 mm anterior-posteriorly. (SEM 0.03–0.05) The inclination changed 0.4 dgr and anteversion 0.4 dgr as well. Most cups moved laterally, proximally and anteriorly with increased anteversion and decreased inclination. No major differences in mean values were found between the groups according translations or rotations and no significant differences. Nor did we find differences between the press fit only and the augmented cups.

Wear was 0.45 mm proximally and in total 0. 6 mm without any sign of differences between the HA and porous coated groups. HA coated cups had less radiolucent lines after 2 years. (p=0.01)

Discussion: The Reflection cups were stable fixed ad we found no indication of inferior stability for cups without augmentation as might have been anticipated. The reason is probably the firm press fit fixation obtained with a stable cup, good bone and forceful impaction. Many use screws for safety but such cups are not sealed for leakage of joint fluid and pressure gradients and the risk for backside osteolyses is higher… Pegs are easier and safer to insert and tighten the holes better. A tight, no hole cup with HA is preferred by us in normal younger patients since HA gave a better interface. Such a solution should minimise the risk for penetration of particles and pressure gradients with less risk for lyses.

Purpose: Instrumentation and cementoplasty have been used individually or synergistically to augment screw fixation for better stabilization. A pilot study was performed to develop a new way to use this relationship to solve problematic screw loosening in both healthy and osteoporotic bone. Results show there may be indication to use the following characterized method.

Methods: In 12 cases of patients, pedicle fixation was used for complex decompression. The ages range from 70–85 years and included 8 females and 4 males. All patients underwent a bone tamp bolus formation in cancellous bone through each pedicle at the superior level of construct (3–4 cc. in each site, injected under low pressure) followed by pedicle screw insertion into the bolus, and subsequent levels were fixated by only pedicle screws.

Results: The preoperative, postoperative, and 3 month follow-up plain x-ray films were evaluated for stable bone tamp implantation, cement leakage, and screw placement. In all 12 cases there was no evidence of screw migration, pull-out, fracture, spinal cord compression, nerve root compression, or complication with cement placement. There was no example of cement extrusion into spinal canal. All patients had uneventful recoveries which included physical therapy, mild analgesics, and bracing.

Conclusion: This new technique may solve the problem of loosening of screws in healthy and osteoporotic bone by providing a more secure anchorage system not yet seen in previous studies. Further study is needed to develop more specific outcomes to determine the best technique using the balloon bone tamp system.

Purpose of the study: Conservative surgical treatment of osteochondritis dissecans (OCD) in adults raises the problem of integration of the sequestered bone. Mechanical techniques using screw fixation are often insufficient to achieve healing. Adjunction of a biological fixation with osteochondral graft tissue for a mosaicplasty might favour integration of the fragment. The purpose of this study was to assess the short-term outcomes in an initial series using a technique called fixation plus where screw fixation is associated with mosaiplasty. Material and methods: This was a retrospective analysis of eight adults who underwent surgery from 2003 to 2008 for stage IIB or III (Bedouelle) OCD of the medial condyle. Loss of subchondral tissue could be filled with a cancellous graft. Clinical and radiographic (Hugston) parameters were noted. At three months, the screws were removed arthroscopically. The ICRS-OCD score was noted. At six months, five patients had an arthroMRI to evaluate fragment integration, determine its signal and vitality. Results: Mean follow-up was 17.4 months (range 3–36). The Hugston score improved from 1.6 (0–3) preoperatively to 3.4 (2–4) postoperatively and the radiological score from 2.5 (2–4) to 3.2 (3–4). The arthroscopy performed to remove the screws revealed integration of the OCD fragment. The ICRS-OCD score was I in two cases, II in five and III in one. The postoperative arthroMRI confirmed continuity with the cartilage at the periphery of the fragment, with no passage of contrast agent into the defect. Discussion: Screw fixation of OCD fragments is often followed by nonunion and thus failure. Moasaicplasty is an alternative but does not preserve quality cartilage cover (curvature, thickness, cover). The technique proposed here ensures osseous integration of he fragment, complete cartilage cover, and a smaller number of osteochondral pits. Fixation Plus associates mechanical and biological fixation with good preliminary clinical results. Comparative longer term assessment is needed to confirm its pertinence

Tibiotalocalcaneal fusion is generally reserved for complex cases such as severe deformity or bone loss, infection, Charcot and revision procedures. Subsequently published series have been small and there are no studies comparing plate fixation and intramedullary nailing. We present the outcomes in the largest series to date and have also compared the union rate and complication rate between blade plate fixation (36) and intramedullary nailing (46). Both groups were well matched for patient and disease factors.

There was a non-statistically significant trend towards better outcomes with nails. Further analysis was conducted comparing the two fixation methods by the indication for surgery, there were no statistically significant differences, the reasons for these findings are discussed.

There exists two important pathologies in degenerative lumbosacral kyphosis (flat back), such as loss of lumbar lordosis and posterior rotation of the pelvis. Patients with this deformity complaint marked fatigue in lumbosacral region and disturbances on standing and walking.

Conservative treatment is seemed to be difficult, and surgical treatment may be selected for this deformity. Our surgical strategy is posterior shortening and anterior rotation of pelvis. Surgical procedure is tranvertebral decancellation closed wedge osteotomy, correction by shortening and lumbosacral fixation by intrasacral method. Radiographic assessment around the hip axis was performed by Jackson method on standing entire spine film.

5 females and 2 males were operated on by this method. Mean age at the operation was 67 yrs (57–82). Mean follow-up was 24 months (12–36). Mean operative time was 480 minutes (320–600). Mean estimated blood loss was 1440ml (985–2415). Mean pelvic angle was 41 degrees before the operation. At follow-up, mean value was 33 degrees. Preoperative mean local kyphosis was 4.7 degrees. Postoperative mean local lordosis was 24.1 degrees, average correction was 30 degrees. No loss of correction occurred in fused area. Clinical symptoms were remarkably improved after the operation. There was no major complication in this series.

Repair of large rotator cuff tears can be a demanding technical exercise, particularly when patients are elderly and tissue quality for repair is poor. In 25 patients we have used a method of tying rotator cuff sutures over a screw fixation post at the level of the surgical neck to secure the torn cuff to the greater tuberosity while healing occured. This study reports the results of these patients. 25 patients (27 shoulders) of average age 68.5 years were reviewed at an average of 22 months post surgery (range 3– 52 months). 4 patients (6 shoulders) were workers compensation injuries. The Constant method of shoulder assessment and visual analogue pain scores were used. Constant scores improved from an average of 30.6 pre-operatively to 75.2 post operatively. Pain scores improved from an average of 7.2 pre-operatively to 2.2 post operatively.

Over 80 % of patients reported being very satisfied with the results of their procedure. 2 patients reported being unsatisfied with their procedure. Workers compensation patients had poorer results for pain and function than the group average but still reported good satisfaction with the procedure. 4 complications occurred. 2 patients had re- tears of their cuff after falls. One was repaired with side to side suturing and the other was re-repaired to the post. 1 wound infection occurred requiring arthroscopic shoulder lavage and final removal of the implant.

This shoulder subsequently healed with good function. One patient had significant shoulder pain requiring surgery and removal of the fixation post. There were no other cases of screw irritation and no axillary nerve palsy or deltoid avulsions were found.

Conclusions: This method of fixation is simple, strong, safe and gives results at least equivalent to if not better than other reported methods. The technique is a useful one to have in the surgical repertoire when dealing with large rotator cuff tears in older patients.

Meniscal root tears can result from traumatic injury to the knee or gradual degeneration. When the root is injured, the meniscus becomes de-functioned, resulting in abnormal distribution of hoop stresses, extrusion of the meniscus, and altered knee kinematics. If left untreated, this can cause articular cartilage damage and rapid progression of osteoarthritis. Multiple repair strategies have been described; however, no best fixation practice has been established. To our knowledge, no study has compared suture button, interference screw, and HEALICOIL KNOTLESS fixation techniques for meniscal root repairs. The goal of this study is to understand the biomechanical properties of these fixation techniques and distinguish any advantages of certain techniques over others. Knowledge of fixation robustness will aid in surgical decision making, potentially reducing failure rates, and improving clinical outcomes. 19 fresh porcine tibias with intact medial menisci were randomly assigned to four groups: 1) native posterior medial meniscus root (PMMR) (n = 7), 2) suture button (n = 4), 3) interference screw (n = 4), or 4) HEALICOIL KNOTLESS (n = 4). In 12 specimens, the PMMR was severed and then refixed by the specified group technique. The remaining seven specimens were left intact. All specimens underwent cyclic loading followed by load-to-failure testing. Elongation rate; displacement after 100, 500, and 1000 cycles; stiffness; and maximum load were recorded. Repaired specimens had greater elongation rates and displacements after 100, 500, and 1000 cycles than native PMMR specimens (p 0.05). The native PMMR showed greater maximum load than all repair techniques (p 0.05). In interference screw and HEALICOIL KNOTLESS specimens, failure occurred as the suture was displaced from the fixation and tension was gradually lost. In suture button specimens, the suture was either displaced or completely separated from the button. In some cases, tear formation and partial failure also occurred at the meniscus luggage tag knot. Native PMMR specimens failed through meniscus or meniscus root tearing. All fixation techniques showed similar biomechanical properties and performed inferiorly to the native PMMR. Evidence against significant differences between fixation techniques suggests that the HEALICOIL KNOTLESS technique may present an additional option for fixation in meniscal root repairs. While preliminary in vitro evidence suggests similarities between fixation techniques, further research is required to determine if clinical outcomes differ

Aims. The primary objective of this registry-based study was to compare patient-reported outcomes of cementless and cemented medial unicompartmental knee arthroplasty (UKA) during the first postoperative year. The secondary objective was to assess one- and three-year implant survival of both fixation techniques. Methods. We analyzed 10,862 cementless and 7,917 cemented UKA cases enrolled in the Dutch Arthroplasty Registry, operated between 2017 and 2021. Pre- to postoperative change in outcomes at six and 12 months’ follow-up were compared using mixed model analyses. Kaplan-Meier and Cox regression models were applied to quantify differences in implant survival. Adjustments were made for patient-specific variables and annual hospital volume. Results. Change from baseline in the Oxford Knee Score (OKS) and activity-related pain was comparable between groups. Adjustment for covariates demonstrated a minimally greater decrease in rest-related pain in the cemented group (β = -0.09 (95% confidence interval (CI) -0.16 to -0.01)). Cementless fixation was associated with a higher probability of achieving an excellent OKS outcome (> 41 points) (adjusted odds ratio 1.2 (95% CI 1.1 to 1.3)). The likelihood of one-year implant survival was greater for cemented implants (adjusted hazard ratio (HR) 1.35 (95% CI 1.01 to 1.71)), with higher revision rates for periprosthetic fractures of cementless implants. During two to three years’ follow-up, the likelihood of implant survival was non-significantly greater for cementless UKA (adjusted HR 0.64 (95% CI 0.40 to 1.04)), primarily due to increased revision rates for tibial loosening of cemented implants. Conclusion. Cementless and cemented medial UKA led to comparable improvement in physical function and pain reduction during the initial postoperative year, albeit with a greater likelihood of achieving excellent OKS outcomes after cementless UKA. Anticipated differences in early physical function and pain should not be a decisive factor in the choice of fixation technique. However, surgeons should consider the differences in short- and long-term implant survival when deciding which implant to use. Cite this article: Bone Jt Open 2024;5(5):401–410

Aims. Isolated acetabular liner exchange with a highly crosslinked polyethylene (HXLPE) component is an option to address polyethylene wear and osteolysis following total hip arthroplasty (THA) in the presence of a well-fixed acetabular shell. The liner can be fixed either with the original locking mechanism or by being cemented within the acetabular component. Whether the method used for fixation of the HXLPE liner has any bearing on the long-term outcomes is still unclear. Methods. Data were retrieved for all patients who underwent isolated acetabular component liner exchange surgery with a HXLPE component in our institute between August 2000 and January 2015. Patients were classified according to the fixation method used (original locking mechanism (n = 36) or cemented (n = 50)). Survival and revision rates were compared. A total of 86 revisions were performed and the mean duration of follow-up was 13 years. Results. A total of 20 patients (23.3%) had complications, with dislocation alone being the most common (8.1%; 7/86). Ten patients (11.6%) required re-revision surgery. Cementing the HXLPE liner (8.0%; 4/50) had a higher incidence of re-revision due to acetabular component liner-related complications than using the original locking mechanism (0%; 0/36; p = 0.082). Fixation using the original locking mechanism was associated with re-revision due to acetabular component loosening (8.3%; 3/36), compared to cementing (0%; 0/50; p = 0.038). Overall estimated mean survival was 19.2 years. There was no significant difference in the re-revision rate between the original locking mechanism (11.1%; 4/36) and cementing (12.0%; 6/50; p = 0.899). Using Kaplan-Meier survival analysis, the revision-free survival of HXLPE fixed with the original locking mechanism and cementing was 94.1% and 93.2%, respectively, at ten years, and 84.7% and 81.3%, respectively, at 20 years (p = 0.840). Conclusion. The re-revision rate and the revision-free survival following acetabular component liner exchange revision surgery using the HXLPE liner were not influenced by the fixation technique used. Both techniques were associated with good survival at a mean follow-up of 13 years. Careful patient selection is necessary for isolated acetabular component liner exchange revision surgery in order to achieve the best outcomes. Cite this article: Bone Joint J 2024;106-B(5 Supple B):59–65

Aims. The optimal management of posterior malleolar ankle fractures, a prevalent type of ankle trauma, is essential for improved prognosis. However, there remains a debate over the most effective surgical approach, particularly between screw and plate fixation methods. This study aims to investigate the differences in outcomes associated with these fixation techniques. Methods. We conducted a comprehensive review of clinical trials comparing anteroposterior (A-P) screws, posteroanterior (P-A) screws, and plate fixation. Two investigators validated the data sourced from multiple databases (MEDLINE, EMBASE, and Web of Science). Following PRISMA guidelines, we carried out a network meta-analysis (NMA) using visual analogue scale and American Orthopaedic Foot and Ankle Score (AOFAS) as primary outcomes. Secondary outcomes included range of motion limitations, radiological outcomes, and complication rates. Results. The NMA encompassed 13 studies, consisting of four randomized trials and eight retrospective ones. According to the surface under the cumulative ranking curve-based ranking, the A-P screw was ranked highest for improvements in AOFAS and exhibited lowest in infection and peroneal nerve injury incidence. The P-A screws, on the other hand, excelled in terms of VAS score improvements. Conversely, posterior buttress plate fixation showed the least incidence of osteoarthritis grade progression, postoperative articular step-off ≥ 2 mm, nonunions, and loss of ankle dorsiflexion ≥ 5°, though it underperformed in most other clinical outcomes. Conclusion. The NMA suggests that open plating is more likely to provide better radiological outcomes, while screw fixation may have a greater potential for superior functional and pain results. Nevertheless, clinicians should still consider the fragment size and fracture pattern, weighing the advantages of rigid biomechanical fixation against the possibility of soft-tissue damage, to optimize treatment results. Cite this article: Bone Jt Open 2024;5(3):227–235

Introduction and Objective. Distal femoral fractures are commonly treated with a straight plate fixed to the lateral aspects of both proximal and distal fragments. However, the lateral approach may not always be desirable due to persisting soft-tissue or additional vascular injury necessitating a medial approach. These problems may be overcome by pre-contouring the plate in helically shaped fashion, allowing its distal part to be fixed to the medial aspect of the femoral condyle. The objective of this study was to investigate the biomechanical competence of medial femoral helical plating versus conventional straight lateral plating in an artificial distal femoral fracture model. Materials and Methods. Twelve left artificial femora were instrumented with a 15-hole Locking Compression Plate – Distal Femur (LCP-DF) plate, using either conventional lateral plating technique with the plate left non-contoured, or the medial helical plating technique by pre-contouring the plate to a 180° helical shape and fixing its distal end to the medial femoral condyle (n=6). An unstable extraarticular distal femoral fracture was subsequently simulated by means of an osteotomy gap. All specimens were tested under quasi-static and progressively increasing cyclic axial und torsional loading until failure. Interfragmentary movements were monitored by means of optical motion tracking. Results. Initial axial stiffness was significantly higher for helical (185.6±50.1 N/mm) versus straight (56.0±14.4) plating, p<0.01. However, initial torsional stiffness in internal and external rotation remained not significantly different between the two fixation techniques (helical plating:1.59±0.17 Nm/° and 1.52±0.13 Nm/°; straight plating: 1.50±0.12 Nm/° and 1.43±0.13Nm/°), p≥0.21. Helical plating was associated with significantly higher initial interfragmentary movements under 500 N static compression compared to straight plating in terms of flexion (2.76±1.02° versus 0.87±0.77°) and shear displacement under 6 Nm static rotation in internal (1.23±0.28° versus 0.40±0.42°) and external (1.21±0.40° versus 0.57±0.33°) rotation, p≤0.01. In addition, helical plating demonstrated significantly lower initial varus/valgus deformation than straight plating (4.08±1.49° versus 6.60±0.47°), p<0.01. Within the first 10000 cycles of dynamic loading, helical plating revealed significantly bigger flexural movements and significantly lower varus/valgus deformation versus straight plating, p=0.02. No significant differences were observed between the two fixation techniques in terms of axial and shear displacement, p≥0.76. Cycles to failure was significantly higher for helical plating (13752±1518) compared to straight plating (9727±836), p<0.01. Conclusions. Although helical plating using a pre-contoured LCP-DF was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, helical plate constructs demonstrated significantly improved endurance to failure, which may be attributed to the less progressively increasing lever bending moment arm inherent to this novel fixation technique. From a biomechanical perspective, helical plating may be considered as a valid alternative fixation technique to standard straight lateral plating of unstable distal femoral fractures