Polyethylene liners of modular acetabular components wear and sometimes need to be replaced, despite the metal shell being well fixed. Replacing the liner is a relatively simple procedure, but very little is known of the outcome of liner revision. We prospectively followed up 1126 Harris-Gallante 1 metal backed, uncemented cups for between 9 and 19 years. 38 (3.4%) liners out of 1126 acetabular components wore and required revision. These revisions were then followed up for a mean of 4.8 years. The rate of dislocation was 28.9%. Nine of the dislocations were single dislocations and 2 were recurrent. The overall re-revision rate was 3 out of 38 total hip replacements (7.9%) at a mean follow up of 4.8 years. This gives a 92.1% survivorship at just under 5 years. In isolated liner revision we had a complication rate of 23%. In liner revision combined with stem revision we had a complication rate of 48%. Possible reasons for high dislocation rates are discussed. Leaving the well fixed acetabular shell in-situ leads to an increased risk of instability. However, this needs to be balanced against the otherwise low complication rate for liner revision. Patients should be consented accordingly

Introduction: Recurrent dislocation can be a significant problem after total hip replacement. The use of a constrained tripolar liner is an option in the surgical treatment of dislocation or instability.

Methods: A retrospective review was carried out of patients identified from a prospective database. All patients had a constrained liner cemented onto a satisfactory pre-existing cement mantle, cemented into a reconstruction ring, or cemented into a well fixed cementless shell. The Osteonics Tripolar Liner was used in all cases; the outer aspect of the liner was prepared with a burr to create grooves and thus improve cement interlock. Data collected included demographics, reason for revision, re-revision rate, outcome and survival.

Results: There were 58 cases identified where a cemented constrained liner was inserted at revision hip surgery. Average age at time of surgery was 77years (range 40–94). There were 9 patients who died with less than 2 years follow-up; they were excluded, leaving a study group of 49 cases. No cases were lost to follow-up. Average duration of follow-up was 46months (range 24–76). There have been 4 infections, one of which required removal of prostheses and a 2-stage revision. There was one case of fall post-operatively and fracture of the contra-lateral femoral neck. There have been 4 implant failures requiring re-revision. All failures were due to disarticulation of the liner, 2 of which occurred in the same patient on separate occasions. There have been no revisions for loosening, and there have been no cases of failure at the bone-cement interface or at the cement-cement interface with the cement-in-cement technique. Overall survival of the cemented constrained liner was 90% at average 3.8years.

Conclusion: This study demonstrates that cementing a constrained liner into the acetabulum is a viable option in revision hip surgery, particularly in the management of instability.

Introduction: Recurrent dislocation is a significant problem after total hip replacement. Aetiology is multifactorial and treatment should address the reason for dislocation. The use of a constrained tripolar liner is an option in the surgical treatment of dislocation.

Methods: A retrospective review was carried out of patients who have undergone revision hip surgery and had a constrained liner cemented into the acetabulum. Patients were identified from a computer database. All patients had a constrained liner cemented onto a satisfactory pre-existing cement mantle, cemented into a reconstruction ring, or cemented into a well fixed cementless shell. The Osteonics Tripolar Liner was used in all cases and the outer aspect of the tripolar liner was prepared with a burr to create grooves and thus improve cement interlock. Data collected included demographics, reason for revision, components used, re-revision rate, outcome and survival.

Results: There were 58 cases identified where a cemented constrained liner was inserted at revision hip surgery. Average age at time of surgery was 77years (range 40–94). Reason for use of a constrained liner was recurrent dislocation in over 95% of cases. There were 9 patients who died with less than 2 years follow-up; they were excluded, leaving a study group of 49 cases. Average duration of follow-up was 46months (range 24–76).

There have been 4 infections, one of which required removal of prostheses and 2 stage revision. There was one case of fall post-operatively and fracture of the contra-lateral femoral neck. There have been 3 implant failures requiring re-revision. All failures were due to disarticulation of the liner, 2 of which occurred in the same patient on separate occasions. There have been no revisions for loosening, and there have been no cases of failure at the bone-cement interface or at the cement-cement interface with the cement-in-cement technique. Overall survival of the cemented constrained liner was 91.8% at average 3.8years.

Conclusion: This study demonstrates that a cemented constrained tripolar liner is a viable option in revision hip surgery, particularly in the treatment of recurrent dislocation.

Polyimide (MP-1, MMATech, Haifa, Israel), is a high performance aerospace thermoplastic used for its lubricity, stability, inertness and radiation resistance. A wear resistant thin robust bearing is needed for total hip arthroplasty (THR). After independent laboratory testing, in 2006, the author used the material as a bearing in two Reflection (Smith and Nephew, USA) hip surgeries. The first, a revision for polyethylene wear, survives with no evidence of wear, noise, new osteolysis or complications related to the MP-1 bearing after 16 yrs. The second donated his asymptomatic MP-1 hip at 6.5yrs for post-mortem examination. There were no osteoclasts, cellular reaction bland in contrast to that of polyethylene. In 2013 a clinical study with ethical committee approval was started using a Biolox Delta (Ceramtec, Germany) head against a polyimide liner in 97 patients. MMATech sold all liners, irradiated: steam 52:45. Sixteen were re-machined in New Zealand. Acetabular shells were Delta PF (LIMA, Italy). The liner locked by taper. The cohort consisted of 46:51 M:F, and ages 43 to 85, mean 65. Ten received cemented stems. For contralateral surgery, a ceramic or polyethylene liner was used. Initial patients were lower demand, later, more active patients, mountain-biking and running. All patients have on-going follow up, including MP-1 liner revision cases. There has been no measurable wear, or osteolysis around the acetabular components using weight-bearing radiographs. Squeaking within the first 6 weeks was noted in 39 number of cases and subtle increase in palpable friction, (passive rotation at 50 degrees flexion), but then disappeared. There were 6 revisions, four of which were related to cementless Stemsys implants (Evolutis, Italy) fixed distally with proximal linear lucencies in Gruen zones 1 and 7, and 2 and 6. No shells were revised and MP-1 liners were routinely changed to ceramic or polyethylene. The liners showed no head contact at the apex, with highly polished contact areas. There were no deep or superficial infections, but one traumatic anterior dislocation at 7 years associated with 5 mm subsidence of a non-collared stem. The initial squeaking and increased friction was due to the engineering of the liner / shell composite as implanted, not allowing adequate clearance for fluid film lubrication and contributed to by shell distortion during impaction. The revised bearings were “equatorial” rather than polar, and with lack of wear or creep this never fully resolved. Where the clearance was better, function was normal. The “slow” utilization was due to my ongoing concern with clearances not being correct. The revision of 4 Stemsys stems, tribology issues may have contributed, but non “MP-1” / Stemsys combinations outside this study have shown the same response, thought to be due to de-bonding of the hydroxyapatite coating. With correct engineering and clearances, a 3.6 mm thick MP-1 bearing, a surface Ra<0.5, steam sterilized, shows no appreciable wear, and with confidence, can be used as a high performance THR bearing

Background. Ultraporous metals have now been used in acetabular reconstruction for two decades with excellent survival. The purpose of this study is to evaluate a newer porous metal made from Ti6Al4V titanium alloy in complex primary and revision hip arthroplasty. Methods. A retrospective review as performed on all total hip arthroplasty (THA) procedures in which a G7 Osseo-Ti (Zimmer Biomet, Warsaw, IN) acetabular component was used between 2015 and 2017. Patients with 2-year minimum follow-up or failure were included, yielding a cohort of 123 patients (126 hips). There were 50 male patients (41%; 51 hips) and 73 females (59%; 75 hips). Mean age was 65 years (range, 43–88) and mean BMI was 30.7 kg/m. 2. (range, 18–56). Indications for ultraporous metal components were in hips with compromised bone stock or severe acetabular deformity. Procedures were 35 complex primary THA and 91 revision THA that included 12 conversions and 24 reimplantations as part of 2-staged exchange for treatment of infection. Results. With an average 3.3-year follow-up (range, 2–5 years), 1 hip in the primary series (2.9%) and 4 hips in the revision series (4.4%) were revised for aseptic loosening of the acetabular component. Three of these re-revisions required custom triflange devices. Five patients (4%) failed for periprosthetic infection, which included 1 primary THA done for rheumatoid arthritis and post-radiation necrosis, and 4 second-stage reimplantation revision THAs for prior infection. Two revision patients, one done for active instability and one multiply revised, subsequently dislocated and required liner revision to constrained constructs. Kaplan-Meier analysis to endpoint of acetabular revision for aseptic loosening was 96.6% (±3.4%) in the primary series and 95.3% (±2.3%) in the revision series. Conclusion. This three-dimensionally printed ultraporous titanium acetabular component demonstrated promising early results in complex primary and revision total hip arthroplasty

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.

Nutritional Status and Short-Term Outcomes Following THA; Initial Metal Ion Levels Predict Risk in MoM THA; THA Bearing Surface Trends in the US ‘07- ’14; Dislocation Following Two-Stage Revision THA; Timing of Primary THA Prior to or After Lumbar Spine Fusion; Failure Rate of Failed Constrained Liner Revision; ESR and CRP vs. Reinfection Risk in Two-Stage Revision?; Mechanical Complications of THA Based on Approach; Impaction Force and Taper-Trunnion Stability in THA; TKA in Patients Less Than 50 Years of Age; Post-operative Mechanical Axis and 20-year TKA Survival and Function; Return to Moderate to High-intensity Sports after UKA; “Running Two Rooms” and Patient Safety in TJA; Varus and Implant Migration and Contact Kinematics after TKA; Quadriceps Snips in 321 Revision TKAs; Tubercle Proximalization for Patella Infera in Revision TKA; Anterior Condylar Height and Flexion in TKA; Compression Bandage Following Primary TKA; Unsupervised Exercise vs. Traditional PT After Primary TKA and UKA

The protective effect of lipped polyethylene uncemented acetabular liners against revision THA for instability has been reported. However, the effect of lip size has not been explored, nor has the effect on revision THA for loosening. We aimed to determine if uncemented acetabular liner geometry, and lip size, influences the risk of revision THA for instability or loosening. 202511 primary THAs with uncemented polyethylene acetabular components were identified from the NJR dataset (2003 – 2017). The effect of acetabular liner geometry and lip size on the risk of revision THA for instability or loosening was investigated using binomial regression and competing risks survival analyses (competing risks were revision for other causes or death) adjusting for age, gender, ASA grade, diagnosis, side, institution type, surgeon grade, surgical approach, head size and polyethylene crosslinking. The distribution of acetabular liners was: neutral – 39.4%, offset neutral – 0.9%, 10-degree – 34.5%, 15-degree – 21.6%, 20-degree – 0.8%, offset reorientating – 2.82%. There were 690 (0.34%) revision THAs for instability and 604 (0.3%) for loosening. Significant subhazard risk ratios were found in revision THA for instability with 10-degree (0.63), 15-degree (0.48) and offset reorientating (1.6) liners, compared to neutral liners. There was no association found between liner geometry and risk of revision THA for loosening. This Registry based study confirms a significantly lower risk of revision THA for instability when a lipped liner is used, compared to neutral liners, and a higher risk with the use of offset reorientating liners. Furthermore, 15degree liners seem to have a lower risk than 10degree liners. We did not find an association between acetabular liner geometry and revision THA for loosening. 10- and 15-degree lipped polyethylene liners seem to offer a lower revision risk over neutral liners, at least at medium term followup. Further studies are required to confirm if this benefit continues into the long-term

Introduction. The number of medial unicompartmental knee replacements (UKR) performed for arthritis has increased and as such, revisions to total knee replacement (TKR) is increasing. Previous studies have investigated survivorship of UKR to TKR revision and functional outcomes compared to TKR to TKR revision, but have failed to detail the surgical considerations involved in these revisions. Our objectives are to investigate the detailed surgical considerations involved in UKR to TKR revisions. Methods. This study is a retrospective comparative analysis of a prospectively collected database. From 2005 to 2017, 61 revisions of UKR to TKR were completed at a single center. Our inclusion criteria included: revision of UKR to TKR or TKR to TKR with minimum 1 year follow-up. Our exclusion criteria include: single component and liner revisions and revision for infection. The 61 UKR to TKR revisions were matched 2:1 with respect to age, ASA and BMI to a group of 122 TKR to TKR revisions. The following data was collected: indication for and time to revision, operative skin to skin surgical time, the use of specialized equipment (augment size/location, stem use), intraoperative and postoperative complications, re-operations and outcome scores (WOMAC, Oxford 12, SF 12, satisfaction score). Results. There were no statistical differences between the demographic data from either group (age, BMI, ASA, sex and follow-up range). Progression of arthritis was the most common reason for revision in the UKR to TKR group (30/61, 49%, p < 0.001). Aseptic loosening was the most common reason for revision in the TKR to TKR group (73/122, 60%,) and was encountered more often than aseptic loosening in the UKR to TKR group (21/61, 35%, p=0.002). The operative time was longer in the TKR to TKR group (77 vs 112 min, p< 0.001). Femoral augmentation was required for one 1/61 (1.64%) UNI and 92/122 (75%) TKR revisions, respectively (p <0.001). Medial tibial augments were required in 9/61 (14.8%) of the UKR to TKR group while 12/122 (10%) and 10/122 (8%) of the TKR to TKR group required medial and full tibial augments, respectively (p=0.7). UKR to TKR revisions never required femoral stems while 120/122 (98%) of the TKR to TKR group did (p<0.001). Tibial stems were required in 19/61 (31%) and 122/122 (100%) of UKR to TKR and TKR to TKR groups, respectively (p<0.001). There was no statistical difference in the overall complication rate of either group (15% in the UKR to TKR group and 13% in the TKR to TKR group, p = 0.9). Stiffness was a common complication of UKR to TKR and TKR to TKR re-revisions at 2/61 (3%), and 6/122 (5%), respectively (P = 0.6). Aseptic loosening was also a common complication of in both groups at 2/61 (3%) and 4/122 (3%) in the UKR to TKR and TKR to TKR groups, respectively (p = 0.7). There was no statistical difference in the re-operation rate of either group (10% in the UKR to TKR group and 7% in the TKR to TKR group, P = 1). Stiffness was the most common indication for re-operation in the UKR to TKR group (2/61, 3%, p = 0.11) while aseptic loosening was the most common in the TKR to TKR group (4/122, 3.2%, p = 0.7). The survivorship in the UKR to TKR was 93% and 90% at 5 and 9 years, respectively. The survivorship in the TKR to TKR group was 95% and 94% at 5 and 9 years, respectively, which was not statistically different from the UKR group. Discussion. The most common reason for revision was different between the two groups (p < 0.001) while the skin to skin time was longer in the TKR to TKR group. In terms of revision components, femoral stems were never required in the UKR to TKR group while tibial stems were only required in 31%. Similarly, medial tibial augments were only required in 15% of the UKR to TKR group. While the surgeon must be prepared to use augmentation and stems in UKR to TKR revisions, they can often be completed with primary components and therefor will have an overall lower cost to the health care system. Furthermore, the survivorship and re-operation between the two groups was similar which supports previous literature. The results of this study will allow for a more in-depth cost-effectiveness analysis of UKR to TKR vs TKR to TKR in arthroplasty decision making. Unicompartmental knee replacements should be considered in appropriate patients to decrease the lifetime cost of arthroplasty intervention and potentially decrease the burden on the health care system. For figures, tables, or references, please contact authors directly

Aims

The primary aim of this study is to assess the survival of the uncemented hydroxyapatite (HA) coated Trident II acetabular component as part of a hybrid total hip arthroplasty (THA) using a cemented Exeter stem. The secondary aims are to assess the complications, joint-specific function, health-related quality of life, and radiological signs of loosening of the acetabular component.

Aims

Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised.

Aims

In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component.

Purpose of Study. To assess the results of Revision Hip Surgery in which a less invasive technique was utilized in situations where a number of different options was available. Method. The authors rely on an experience of 3,445 hip arthroplasties by a single surgeon over a period of 20 years, of which approximately 20% were revision cases. Of these 617 cases, we report on 175 in which a minimally invasive option was taken. This does not apply to the skin incision, as all cases were adequately exposed. We have adopted this term to describe cases in which a surgical options was taken that resulted in the least morbidity and the shortest surgical time. We postulated that would lead to the best outcomes with the least complications. Acetabular revisions: 1) Isolated polyethylene exchange. 2) Liner revision with cement technique in cases of cup malposition or poor locking mechanism. 3) Revision of cup with a primary prosthesis with significant medial bone loss. Stem revisions: 1) Cement on cement technique. 2) Strut graft and primary stem. Results. We found a very low complication rate utilizing these methods: Fatal pulmonary emboli: 0 Sepsis: 2 Dislocations 3 Repeat revisions 3. Conclusion. Revision surgery offers many challenges that tend to be compounded with successive operations. We believe that good results can be achieved when a philosophy of minimally invasive surgery is adopted. NO DISCLOSURES

Aims. To assess the early subsidence rate of the femoral stem for patients who had collarless Corail total hip replacement. Methods. Consecutive data was collected retrospectively between August 2007 and December 2009 for patients who had collarless Corail total hip replacement. Radiographic assessment of the degree of subsidence, calcar resorption, stem angulation, canal fill ratio and loosening of the stem were measured. Post operative pain, dislocation and stem revision surgery were also evaluated. Results. 48 patients were identified, providing 51 hips for the study. There were 22 male and 26 female. The mean age 64.2 years (range 38-77). Post-operative radiographs were taken at day 1, 6 weeks and one year post-operatively (range 10-18 months, mean 12.7). Significant subsidence was defined as 3 or more millimetres, we identified two patients with subsidence between 3-5mm, one patient with 6mm and two patients with 10mm subsidence at one year post-operatively. In the 5 patients with subsidence post-operatively, all significant subsidence occurred within the first 6 weeks. Canal fill ratio was measured in all patients; in the non-subsided group the ratio was an average of 72% in the lower third of the stem and 84% in the middle third. In the subsided group 75% in the lower third of the stem and 81% in the middle third, which we felt was clinically insignificant. There was no dislocation or revision for septic loosening. One patient with 10mm subsidence had liner revision for dissociation but the stem was well fixed and not revised. All patients who had significant subsidence still had functioning implants with no pain, revisions for subsidence or features of loosening. Discussion. There were no radiological features predictive of subsidence in our patients. Subsidence may be due to lack of compliance in some patients with partial weight bearing and increased Body Mass Index

Background: Because of his tribologic properties Alumina on alumina bearing for THA is an attractive alternative to the the other traditional bearings surfaces and is used since about forty years, especially for young peoples. In order to resolve the problem caused by the rigidity of ceramic, the ceramic sandwich liner was introduced but some cases of ceramic fracture were reported. The purpose of this study was to quantify and analyse these specific failure. Methods: Between November 1999 and February 2008, a total of 353 CÉRASUL. ®. (Zimmer, Winterthour, Suisse) liner acetabular component with a 28 mm alumina head were implanted in 298 patients. The results were reviewed at a mean of 3,5 years postoperatively with 6 patients loss to follow-up. Clinical follow-up with the PMA score and plain radiographic evaluation were performed. Based on Xray analysis, ceramic sandwich liner fractures were counted and analyzed. Results: The mean PMA was 17,5 (10 to 18) at the final review. Kaplan-Meier survival curves were constructed for the outcomes of revision for any reasons and for ceramic liner fracture. Seven fractures (2%) of ceramic sandwich liner were found and occured at a mean of 4,3 years after surgery without trauma. Fractures (20%) were the third diagnosis leading to the liner revision after dislocation (43%) and sepsis (26%). Neither patient related factors nor X ray position of the implants could be isolated as risk factor of liner fracture. Discussion: Despite promising short term results in term of clinical and Xray analysis, ceramic sandwich liner is associated with a high rate of fracture. This complication have been already reported by other authors for different devices of the same concept ; instead of their conclusions, we were unabled to identify any risk factor of fracture. We hypothesised that repetitive impingement of the stem neck could be the first event of that disappointing complication. Due to this high rate of fracture we discontinued to implant ceramic sandwich liner for THA

Revision total hip arthroplasty, with retention of well fixed femoral and acetabular components and exchange of modular femoral heads and acetabular liners, is seeing increasing usage, primarily for the treatment of osteolysis or recurrent dislocations. The purpose of this study was to determine the dislocation rate after this procedure. From January 1993 to December 2000, 54 patients underwent isolated head and liner exchange performed by two surgeons. These patients have been followed bi-annually with clinical and radiographic evaulation. There were 36 males and 18 females. Diagnoses at the time of revision surgery were recurrent dislocations in 27 and osteolysis in 27. The overall dislocation rate was 11% (6/54). In the 49 non-constrained revisions, a 28 mm diameter femoral head was used in 27 and a 32 mm head in 22. At the time of revision, 60% of the femoral heads were lengthened, 40% were increased in diameter, and 25% were increased in both dimensions. Hooded or later-alised liners were used in 55% of the revisions. Operative stability was documented in all operative notes, and in 85% Ranawat’s sign was used to determine liner placement based on relative component version. The dislocation rate in the non-constrained revisions was 8% (4/49). Two out of five constrained revisions, performed for recurrent dislocations, subsequently dislocated. In this study isolated head and liner revision had a comparable dislocation rate to full revision total hip arthroplasty

Revision of a failed acetabular reconstruction in total hip arthroplasty (THA) can be challenging when associated with significant bone loss. In cementless revision THA, achieving initial implant stability and maximising host bone contact is key to the success of reconstruction. Porous tantalum acetabular shells may represent an improvement from conventional porous coated uncemented cups in revision acetabular reconstruction associated with severe acetabular bone defects. Methods: We reviewed the clinical and radiographic results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects done with a hemispheric, tantalum acetabular shell (Trabecular Metal Revision Shell, Zimmer, Warsaw, USA) and multiple supplementary screws for fixation. Results: At a mean follow-up of 40 (24–51) months, one acetabular shell had been revised in a patient with a Paprosky 3B defect. Two liner revisions were performed for recurrent instability, without porous tantalum shell revision. The clinical outcome showed significant postoperative improvement in all measured sub-scales, compared with baseline pre-operative scores (mean improvement in Oxford Hip Score of 40.0, p < 0.001, in WOMAC of 36.7, p < 0.001, Physical component SF-12 of 12.3, p =0.0003, mental component of SF-12 of 6.8, p = 0.006). Radiographic evidence of osseointegration using validated criteria (Moore’s criteria) was demonstrated in 39 of the 40 hips available for radiographic analysis at a mean of 30.9 months, by two independent observers. Of the remaining six hips, five hips were lost to follow-up and one radiograph demonstrated failure of the hip reconstruction secondary to loss of fixation and superior migration of the component. Discussion: Cementless acetabular revision with the porous tantalum acetabular shell demonstrated excellent early clinical and radiographic results in a series of complex revision acetabular reconstruction associated with severe bone defects. The evidence of radiographic osseointegration suggests that outcome should remain favourable, however, further longer-term evaluation is warranted

Summary Statement. We analysed impaction bone grafting used together with cemented or uncemented fixation in acetabular revision surgery. The overall risk for re-revision did not differ between the cemented and uncemented group. However, aseptic loosening was more common in the cemented group. Background. Several surgical techniques address bone defects in cup revision surgery. Bone impaction grafting, introduced more than thirty years ago, is a biologically and mechanically appealing method. The primary aim of this study was to evaluate the effect of bone impaction grafting when used with uncemented and cemented fixation in cup revision surgery. Uncemented cups resting on more than 50% host bone were used as controls. Patient and Methods. Cup fixation was studied in ninety hips (eighty-two patients), revised due to loosening between 1993 and 1997. There were fifty-three isolated cup and thirty-seven total revisions. Patients were followed for thirteen years using conventional radiography, radiostereometry (RSA), Harris Hip score and a pain questionnaire. Peroperatively the surgeon assessed the acetabular bone bed vitality. In hips where the cup was judged to rest on > 50% vital bone (group I, n=43), an uncemented cup was used. If the cup was resting on ≤ 50% living bone, uncemented (group IIa, n=21,) or cemented (group IIb, n=26) technique was chosen, according to the surgeon's preference. The mean age of patients at index revision was 61±12 years, 56% were females. The most common index diagnosis was primary osteoarthritis (n=45) followed by rheumatoid arthritis (n=10). Results. At thirteen years, acetabular component failure had necessitated a second revision in 6/7/8 hips in Groups I/IIa/IIb respectively. These re-revisions were performed 1–10 (mean 7.1) years after index revision. Moreover four cup / liner revisions were performed in hips with femoral loosening, not allowing further RSA measurements. These twenty-five hips were followed until re-revision. Deceased patients (n=21) and patients with deteriorating medical condition, not able to attend the follow-up (n=7), were censored in the survival statistics. Aseptic loosening was the most common reason of re-revision. However, in the uncemented groups (I/IIa), four cups were re-revised due to liner wear, osteolysis or instability. In the total study population, and up to two years, the median proximal migration was lowest in Group I followed by Group IIa and Group IIb (p≤0,006). At thirteen years the mean proximal migration was highest in Group IIb 1.29 mm (SD 1.23) followed by Group I 0.30 mm (SD 0.40) and Group IIa 0.22 mm (SD 0.22), p = 0.05. In cases subsequently re-revised because of loosening or with radiographically loose cups at the last follow-up, a higher proximal migration was observed compared to the non-revised and radiographically well-fixed group (up to seven years: p < 0.001; thirteen years: p=0.04). Discussion/Conclusion. We found an increased risk for rerevision in cases with less than 50% host bone-implant contact. These cups showed high early proximal migration, measured by RSA, indicating poor initial fixation. Rate of re-revision due to any reason did not differ between cemented and uncemented cups. The cemented group (IIb) had a higher risk of being re-revised due to aseptic loosening. Poor bone stock, use of small bone chips, inferior impaction technique, and no or restricted contact with living bone are probable reasons for failures when extensive bone grafting is needed

Isolated liner exchange in revision total hip arthroplasty for the treatment of polyethylene wear is an increasingly common surgical procedure. Twenty-four hips underwent this procedure via the direct lateral approach and were prospectively followed clinically and radiographically. Accessible osteolytic lesions were curetted and bone grafted. At a mean follow-up of forty months, a significant clinical improvement was observed. One cup collapsed into an osteolytic lesion postoperatively; all other lesions regressed. No dislocations have occurred. Isolated liner exchange via the direct lateral approach may reduce dislocation rates while avoiding the morbidity associated with the removal of well-fixed components. The purpose of this study was to evaluate the clinical and radiographic results of isolated liner exchange in revision total hip arthroplasty (THA) for osteolysis and polyethylene wear via the direct lateral surgical approach. Retention of well-fixed implants avoids unnecessary bone loss at revision surgery. Previous studies report a significant dislocation rate with isolated liner exchange. Revision via the direct lateral surgical approach may reduce the dislocation rate in surgery for acetabular osteolysis. Twenty-four hips that underwent an isolated liner exchange revision procedure via the direct lateral approach were prospectively followed. Accessible osteolytic lesions were curetted and bone grafted. Harris Hip Score, WOMAC Index, and radiographic analysis were recorded. The area of osteolytic lesions was calculated using a computer imaging technique. At mean follow-up of forty months, all except one of the osteolytic lesions had regressed in size. Mean Harris Hip scores improved from sixty-nine to eighty-three and WOMAC indices improved from thirty-seven to twenty-four. No dislocations have occurred. One cup collapsed into an osteolytic lesion postoperatively, requiring an acetabular revision procedure. Isolated liner exchange is a promising technique that avoids the removal of well-fixed acetabular implants. The increased dislocation rate associated with revision THA may be reduced and osteolytic lesions may be debrided and bone grafted through the direct lateral approach. Isolated liner exchange via the direct lateral approach reduces the dislocation rate in THA. Retention of wellfixed implants and bone grafting is a procedure that preserves bone stock and addresses osteolytic lesions at revision surgery

Aims

The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs).