Pelvic discontinuity is a separation through the acetabulum with the ilium displacing superiorly and the ischium/pubis displacing inferiorly. This is a biomechanically challenging environment with a high rate of failure for standard acetabular components. The cup-cage reconstruction involves the use of a highly porous metal cup to achieve biological bone ingrowth on both sides of the pelvic discontinuity and an ilioischial cage to provide secure fixation across the discontinuity and bring the articulating hip center to the correct level. The purpose of this study was to report long term follow up of the use of the cup-cage to treat pelvic discontinuity.

All hip revision procedures between January 2003 and January 2022 where a cup-cage was used for a hip with a pelvic discontinuity were included in this retrospective review. All patients received a Trabecular Metal Revision Shell with either a ZCA cage or TMARS cage (Zimmer-Biomet Inc.). Pelvic discontinuity was diagnosed on pre-operative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed with failure defined as revision of the cup-cage reconstruction.

Fifty-seven cup-cages in 56 patients were included with an average follow-up of 6.25 years (0.10 to 19.98 years). The average age of patients was 72.09 years (43 to 92 years) and 70.2% of patients were female. The five year Kaplan-Meier survival was 92.0% (95% CI 84.55 to 99.45) and the ten year survival was 80.5% (95% CI 58.35 to 102.65). There were 5 major complications that required revision of the cup-cage reconstruction (3 infections and 2 mechanical failures). There were 9 complications that required re-operation without revision of the cup-cage reconstruction (5 dislocations, 3 washouts for infection and one femoral revision for aseptic loosening).

In our hands the cup-cage reconstruction has provided a reliable tool to address pelvic discontinuity with an acceptable complication rate.

Patients undergoing revision surgery of a primary total hip arthroplasty often exhibit bone loss and poor bone quality, which make achieving stable fixation and osseointegration challenging. Implant components coated in porous metals are used clinically to improve mechanical stability and encourage bone in-growth. We compared ultra-porous titanium coatings, known commercially as Gription and Porocoat, in an intra-articular model by press-fitting coated cylindrical implants into ovine femoral condyles and evaluating bone in-growth and fixation strength 4, 8 and 16 weeks post-operatively.

Bilateral surgery using a mini-arthrotomy approach was performed on twenty-four Dorset-Rideau Arcott rams (3.4 ± 0.8 years old, 84.8 ± 9.3 kg) with Institutional Animal Care Committee approval in accordance with the Canadian Council on Animal Care. Cylindrical implants, 6.2 mm in diameter by 10 mm in length with surface radius of curvature of 35 mm, were composed of a titanium substrate coated in either Porocoat or Gription and press-fit into 6 mm diameter recipient holes in the weight-bearing regions of the medial (MFC) and lateral (LFC) femoral condyles. Each sheep received 4 implants; two Gription in one stifle (knee) and two Porocoat in the contralateral joint. Biomechanical push-out tests (Instron ElectroPuls E10000) were performed on LFCs, where implants were pushed out relative to the condyle at a rate of 2 mm/min. Force and displacement data were used to calculate force and displacement at failure, stiffness, energy, stress, strain, elastic modulus, and toughness. MFCs were fixed in 70% ethanol, processed undecalcified, and polished sections, approximately 70 µm thick (Exakt Micro Grinding system) were carbon-coated. Backscattered electron images were collected on a scanning electron microscope (Hitachi SU3500) at 5 kV and working distance of 5 mm. Bone in-growth within the porous coating was quantified using software (ImageJ). Statistical comparisons were made using a two-way ANOVA and Fisher's LSD post-hoc test (Statistica v.8).

Biomechanical evaluation of the bone-implant interface revealed that by 16 weeks, Gription-coated implants exhibited higher force (2455±1362 N vs. 1002±1466 N, p=0.046) and stress (12.60±6.99 MPa vs. 5.14±7.53 MPa, p=0.046) at failure, and trended towards higher stiffness (11510±7645 N/mm vs. 5010±8374 N/mm, p=.061) and modulus of elasticity (591±392 MPa vs. 256±431 MPa, p=0.61). Similarly, by 16 weeks, bone in-growth in Gription-coated implants was approximately double that measured in Porocoat (6.73±3.86 % vs. 3.22±1.52 %, p=0.045). No statistically significant differences were detected at either 4 nor 8 weeks, however, qualitative observations of the exposed bone-implant interface, made following push-out testing, showed more bony material consistently adhered to Gription compared to Porocoat at all three time points. High variability is attributed to implant placement, resulting from the small visual window afforded during surgery, unique curvatures of the condyles, and presence of the extensor digitorum longus tendon which limited access to the LFC.

Ultra-porous titanium coatings, know commercially as Gription and Porocoat, were compared for the first time in a challenging intra-articular ovine model. Gription provided superior fixation strength and bone in-growth, suggesting it may be beneficial in hip replacement surgeries where bone stock quality and quantity may be compromised.

The use of total hip arthroplasty in adolescents for end-stage degenerative hip disease is controversial with few reported outcomes in the literature. The purpose of the study was to report the outcomes of total hip arthroplasty in a cohort of adolescents managed by a multidisciplinary team of paediatric and adult orthopaedic surgeons from a single centre.

A multidisciplinary clinic consisting of paediatric and adult hip surgeons was established in 2013 to identify, treat and prospectively follow adolescents who would potentially beneift from a total hip arthoplasty. To date 29 consecutive adolescent patients (20 female, 9 male, 32 hips) with end stage degenerative hip disease have undergone cementless primary total hip arthroplasty. Mean age at decision to treat was 15.7 years (age 11.4–18.5). Ten different underlying paediatric specific pathologies were documented including DDH, cerebral palsy, JIA, skeletal dysplasias, SCFE and idiopathic chondrolysis. Three patients had bilateral staged procedures. Clinical baseline and outcomes were measured using Oxford Hip Score (OHS), WOMAC score and ASKp scores. Radiographic follow-up was conducted at 6 weeks, 6 months and yearly thereafter. Post-operative complications were recorded.

Twenty-five hips were eligible for minimum 2-year follow-up scoring at a mean 2.7 years (2.0–3.6 years). No intraoperative complications occurred. One case of recalcitrant postoperative psoas tendonitis occured. OHS improved from 25 (7–43) to 41 (23–48). WOMAC improved from 48 (12–8) to 12 (1–44), and ASKp improved from 78% (33–98%) to 93% (73–100%). Radiographic review revealed acceptable alignment of all components with no signs of loosening or wear. No revision of components was required. One patient died at 6 months post op from an unrelated condition.

The early term results of total hip arthroplasty in adolescents from our multidisciplinary program are encouraging. Improvements in quality of life to normal values were seen as were hip scores consistent with satisfactory joint function. Depite the range of complex and varied causes of arthritis seen in this population the establishment of combined paediatric and adult orthopaedic surgical teams appears to be a successful model to manage end-stage degenerative hip disease in adolescents.

Patients with longstanding hip fusion are predisposed to symptomatic degenerative changes of the lumbar spine, ipsilateral knee and contralateral hip¹. In such patients, conversion of hip arthrodesis to hip replacement can provide relief of such symptoms^{2 – 4}. However, this is a technically demanding procedure associated with higher complication and failure rates than routine total hip replacement.

The aim of this study was to determine the functional results and complications in patients undergoing hip fusion conversion to total hip replacement, performed or supervised by a single surgeon.

Twenty-eight hip fusions were converted between 1996 and 2016. Mean follow up was 7 years (3 to 18 years). The reasons for arthrodesis were trauma 11, septic arthritis 10, and dysplasia 7. The mean age at conversion was 52.4 years (26 to 77).

A trochanteric osteotomy was performed in all hips. Uncemented components were used. A constrained liner was used in 7 hips. Heterotopic ossification prophylaxis was not used in this series.

HHS improved a mean of 27 points (37.4 pre-op to 64.3 post-op). A cane was used in 30% of patients before conversion and 80% after.

Heterotopic ossification occurred in 12 (42.9%) hips. There was 2 peroneal nerve injuries, 1 dislocation, 1 GT non-union and 1 infection.

There have been 5 revisions; 2 for aseptic loosening, 1 for infection, 1 for recurrent dislocation and 1 for leg length discrepancy.

Conversion of hip fusion to hip replacement carries an increased risk of heterotopic ossification and neurological injury. We advise prophylaxis against heterotropic ossification. When there is concern about hip stability we suggest that the use of a constrained acetabular liner is considered. Despite the potential for complications, this procedure had a high success rate and was effective in restoring hip function.

Purpose

Two-stage re-implantation after infection of Total Knee Arthroplasty (TKA), remains the gold standard to which other forms of treatment should be compared. The primary purpose of this study was to determine the rates of failure and functional outcome of two stage revision TKA for treatment of infection comparing cemented posterior stabilized compared to constrained condylar implants.

Purpose

Infection following total knee arthroplasty is a devastating complication, requiring considerable effort on the part of the surgeon to eradicate the infection and restore joint function. Two-stage revision is the standard of care in the treatment of peri-prosthetic infection, using a temporary antibiotic-impregnated spacer between procedures. However, controversy remains concerning the use of static versus dynamic spacers, as well as the spacer material. The purpose of this study was to evaluate the clinical outcomes and complications of two-stage revision total knee arthroplasty in patients treated with a metal-on-polyethylene articulating spacer, as compared to those treated with a static antibiotic-impregnated cement spacer at the same centre.

Introduction

A deficient abductor mechanism leads to significant morbidity and few studies have been published describing methods for reconstruction or repair. This study reports the reconstruction of hip abductor deficiency using human allograft.

Introduction

Revision hip arthroplasty with massive proximal femoral bone loss remains challenging. Whilst several surgical techniques have been described, few have reported long term supporting data. A proximal femoral allograft (PFA) may be used to reconstitute bone stock in the multiply revised femur with segmental bone loss of greater than 8 cm. This study reports the outcome of largest case series of PFA used in revision hip arthroplasty.

Purpose

The literature indicates that the tibial component in total knee arthroplasty (TKA) should be placed in internal rotation not exceeding 18 to the line connecting the geometrical center of the proximal tibia and the middle of the tibial tuberosity. These landmarks may not be easily identifiable intraoperatively. Moreover, an angle of 18 is difficult to measure with the naked eye.

Purpose: Component malrotation is a recognized cause of post total knee arthroplasty (TKA) pain. The objective of this study was to evaluate the functional outcomes of TKA revision for component malrotation, and to compare it to revision surgeries for aseptic loosening as a control comparison group.

Method: Twenty four patients who had TKA revision due to component malrotation as the only objective abnormality were reviewed. Only patients with preoperative computerized tomography (CT) documentation of 3° or more malrotation of at least one of the components were included. Mean combined rotation was 6.8° (range, − 12 − 3) excessive internal rotation. Twenty four matched control patients had TKA revision due to aseptic loosening.

Results: Mean follow up was 37 months (range, 24–65). Mean interval from index surgery was 41 months (range, 24–65) for the study group and 98 months (range, 11–222) for the control group (p=0.0003). Preoperative Knee Society Score (KSS) improved by 49 points (range, 16–80) at 6 months postoperatively for the malrotation patients and by 39 (range, − 7–78) for the loosening patients (p=0.08). At last follow-up, KSS was 80 (range, 60–89) for the malrotation group and 75 (range, 26–90) for the loosening group (p=0.14).

Conclusion: We recommend the use of CT scans in evaluation of all patients with early painful TKA’s and no objective evidence of infection. When component malrotation is demonstrated, we believe the results of this study validate consideration of early revision.

Introduction: The objective for this study was to assess the long term results for minor column allograft used in revision hip arthroplasty.

Methods: We prospectively included patients undergoing acetabular cup revision using minor column allograft with a minimum of 5 years follow-up. Minor column allograft was used in uncontained acetabular bone defects of sizes between 30% and 50% of the acetabulum. Acetabular failures requiring re-revisions at any time after surgery were included. Acetabular failure for any cause requiring re-revision surgery was used as end-point. Graft failure was considered when re-revision required the concurrent use of structural bone graft, metal augments or excision arthroplasty for any cause.

Results: There were 65 cases that met the study criteria. We included 5 deaths with a mean follow-up of 11.9 years (6.8–14.8) and 10 losses to follow-up after a mean follow-up of 11.7 years (5.3–17.4). Twenty eight acetabulum failed, with 14 occurring before 5 years at a mean of 1.8 years (0.1–4.8) and 14 occurring after 5 years at a mean of 12.2 years (5.6–23.2). Causes included aseptic loosening (23), infection (2), dislocation (1), graft non-union (1) and cup fracture (1). Fourteen grafts failed, with 8 occurring before 5 years at a mean of 1.2 years (0.5–4) and 6 occurring after 5 years at a mean of 11.3 years (6–23.2) after surgery. The mean improvement in modified Harris Hip Scores was 32.3 at 1 year and 32.6 at last follow-up assessment. The cup survivorship was 56.9 % and graft survivorship 78.5 % at a mean follow-up of 16.3 years (5.3–24.8).

Discussion: Metal augments have been used in revision arthroplasty for low demand patients but we recommend the use of minor column allografts in higher demand patients who are more likely to require further revision surgery.

Purpose: An Osteochondral defect in the knees of young active patients represents a challenge to the orthopedic surgeon. Early studies on allogenic cartilage transplantation showed this tissue to be immunologically privileged, showed fresh grafts to have hyaline cartilage, and surviving chondrocytes present several years after implantation.

Method: Since January 1978 until October 1995 we enrolled 72 patients in a prospective non-randomized study of fresh osteochondral allografts in our institute. Ten international patients which were lost to follow-up were excluded. The major indications for the procedure were: patients younger than 60 years of age having post-traumatic unipolar defects larger than three cm in diameter and one cm in depth.

Results: Sixty two patients, ages 11–57 (mean 28) were followed for 15–31 years (mean 20.4 years). The etiology for the osteochondral defect was traumatic injury to the knee in 41 patients (66%), Osteochondritis Dissecans in 15 patients (24%), and in six patients (10%) due to other pre-existing conditions. Twenty of the 62 grafts have failed, with five having graft removal and 15 converted to total knee replacement. Three patients died during the course of this study due to unrelated causes. The Kaplan-Meier survivorship analysis showed: 92%, 79%, 56%, and 49% graft survival at 10, 15, 20, and 25 years respectively, (median survival = 23 years). Patients with surviving grafts had good function, with a modified Hospital for Special Surgery score of an average 88 at 20 years or more following the allograft transplantation surgery.

Conclusion: Through this long term study the authors confirm the value of fresh osteochondral allografts as a long term solution for large articular defects in the knees of young patients. The improvement of patients’ outcome compared to the previous published results of our earlier studies could be attributed to improved surgical techniques and increasing expertise of the senior authors. We therefore recommend the use of fresh osteochondral allografts for treatment of large osteochondral defects in the distal femur of young and active patients.

Purpose: The literature regarding the outcome of total knee arthroplasty following distal femoral varus osteotomy is limited. The largest published series to date of eleven such patients suggested that medio-lateral constrained implants are commonly required as ligament balancing is difficult. This study presents mid-term outcomes of patients treated with total knee arthroplasty following distal femoral varus osteotomy at a single center.

Method: Twenty-two consecutive distal femoral varus osteotomies (21 patients) converted to total knee arthroplasties were reviewed at a mean follow-up of five years (range, two to 14 years). The mean duration between osteotomy and conversion to arthroplasty was 12 years (range, three to 21 years). In 14 patients (15 knees) the underlying etiology for the femoral osteotomy was primary knee osteoarthritis with valgus deformity, while in seven patients the procedure was performed to unload a fresh osteochondral allograft of either the lateral tibia (five patients) or femur (two patients). It is the authors’ routine to use posterior stabilized implants were used in all total knee arthroplasty surgeries. Femoral stems were used in six knees in which the bone quality was clinically determined by the surgeon to be sufficiently deficient to predispose to periprosthetic fractures, while the remaining sixteen knees were treated with unstemmed components. Modified knee society scores were used to evaluate the clinical outcomes preoperatively and at most recent follow-up.

Results: The mean knee society knee and function scores in surviving knees improved from 50 points (range, 10 to 75 points) and 50 points (range, 30 to 70 points) pre-operatively, to 91 points (range, 67 to 100 points) and 64 points (range, 50 to 70 points) at final follow-up, respectively. The mean arc of motion improved from 94 degrees (range, 70 to 115 degrees) to 114 degrees (range, 90 to 130 degrees). Two patients underwent revision arthroplasty for polyethylene wear and component loosening at eight and 11 years following the index arthroplasty, respectively. There were no fractures, infections or wound complications.

Conclusion: Total knee arthroplasty following distal femoral varus osteotomy reliably decreases pain and improves knee function. Standard posterior stabilized components provide satisfactory stability after appropriate ligamentous balancing, without the need for stemmed or highly constrained components in the majority of patients.

Purpose: Acetabular component revision in the context of large, contained bone defects with less than 50% host-bone-contact traditionally required roof reinforcement or antiprotrusio cages. Trabecular Metal (TM) cups (Zimmer, Warsaw, Indiana) may offer a viable treatment alternative. The objective of this study was to evaluate the clinical and radiological outcome of this mode of treatment.

Method: Fifty-four hip revision acetabular arthroplasty procedures performed with TM cups for contained defects offering ≤50% contact with native bone were prospectively followed. Average follow-up was 45 months (range 24–71). All patients were clinically and radiographically evaluated for evidence of loosening or failure.

Results: Contact with bleeding host bone ranged from 0 to 50% (average 23%). At latest follow up 43 (79.6%) arthroplasties had excellent or good results, 8 (14.8%) cases had medium or fair results and 3 cases (5.6%) had poor results. Two cups failed and had to be revised. Two additional cups had radiological evidence of probable loosening. Overall preliminary survivorship of the revision acetabulae was 96%. Complications included 4 dislocations and 1 sciatic nerve palsy.

Conclusion: Treatment of cavitary defects with less than 50% host-bone contact with using TM cups, without structural support by augments or structural bone grafts, is a viable option.

Purpose: Pelvic discontinuity associated with bone loss is a complex challenge in acetabular revision surgery. Reconstruction with anti protrusion cages, Trabecular Metal (Zimmer, Warsaw, Indiana) cups and morselized bone (Cup-Cage) constructs is a relatively new technique used by the authors for the past 6 years. The purpose of the study was to examine the clinical outcome of these patients.

Method: Thirty-two consecutive acetabular revision reconstructions in 30 patients with pelvic discontinuity and bone loss treated by cup cage technique between January 2003 and September 2007 were reviewed. Average clinical and radiological follow up was 38.5 ± 19 months (range 12 – 68, median 34.5). Failure was defined as component migration > 5mm.

Results: In 29 (90.6%) patients there was no clinical or radiographic evidence indicative of loosening at latest follow up. Harris Hip Scores improved significantly (p< 0.001) from 46.6 ± 10.4 to 78.7 ± 10.4 at 2 year follow up. In 3 patients the construct migrated at 1 year post surgery. One construct was revised to anti protrusion cage with a structural graft while the other was revised to a large Trabecular Metal cup. The third patient is scheduled for revision. Complications included 2 dislocations, 1 infection and 1 partial peroneal nerve palsy. Two patients died due to unrelated reasons at 1 and 3 years post surgery, respectively.

Conclusion: Treatment of pelvic discontinuity by Cup-Cage construct is a reliable option based on preliminary results which suggest restoration of the pelvic mechanical stability. However, patients should be followed closely in order to detect cup migration until satisfactory bony ingrowth into the cup takes place.

Objectives: Fresh osteochondral allografts are well-established treatment for patients who have posttraumatic osteochondral defects over 3cm in diameter and 1cm in depth of the knee. The objective of our study was to investigate the long-term outcome of these grafts and how long they may delay need for arthroplasty in patients with mal-united tibial plateau fractures.

Method: A prospective cohort study of patients who had received fresh osteochondral allografts of the tibial plateau was conducted. 118 patients were identified and survivor ship analysis was performed using conversion to total knee arthroplasty as the end point for graft failure. The Modified Hospital for Knee Surgery Scoring System (MHKSS) was used to clinically assess each patient who had more than five years of follow up. Radiographs were assessed for mechanical axis as well as using the Tonis grade for degenerative change.

Results: 29 of 118 (25%) experienced graft failure and underwent conversion to total knee arthroplasty, at a mean of 12 years (range 3–23) after the index procedure. The remaining 52 patients with a successful graft, and follow up over five years, had a mean MHKSS score of 83 (range 49–100) with a mean follow up of 11.7 years (range 5–34). Kaplan-Meier survivorship analysis of all 118 patients showed that graft survivorship was 94% at 5 years (std err 2.7), 83% at 10 years (std err 4.6), 62% at 15 years (std err 7.4) and 45% at 20 years (std err 8.5). Factors that predicted a successful graft were, using a meniscal allograft in conjunction with the osteochondral graft, and a lateral tibial plateau defect. The age at the time of surgery was no different between the patients that had a successful graft or those that failed.

Conclusion: Fresh osteochondral allografting works well in providing long term treatments for patients with tibial plateau damage. The concurrent use of meniscal allografts is also recommended.

Purpose: Fresh osteochondral allograft (FOCA) transplantation has been an effective treatment option with promising long-term clinical outcomes for focal post-traumatic or intra-articular lesions in the knee for young, active individuals. The goal of this study was to assess the osteochondral allograft to characterize the histopathologic features of early and late graft failure, as well as prolonged graft survival.

Method: We examined histological features of thirtyfive fresh osteochondral allograft specimens retrieved at the time of subsequent graft revision, osteotomies or total knee arthroplasty.

Results: The graft survival time in our samples ranged from one to twenty-five years based on their time to reoperation. Histological features of early graft failures were lack of chondrocyte viability, loss of matrix cationic staining, and features of mechanical instability. Histological features of late graft failures were fracture through the graft, active and incomplete remodelling of the graft bone by the host bone, and resorption of the graft tissue by synovial inflammatory activity at graft edges. Histological features associated with long-term allograft survival included viable chondrocytes, functional preservation of matrix, and complete replacement of the graft bone with the host bone. These long-term histological findings correlate clinically with excellent Oxford Knee Scores (mean 17.5) in age-matched cohorts with allograft transplants surviving 20 (mean 20.9) years or longer.

Conclusion: Given chondrocyte viability, long-term allograft survival depends on graft stability by rigid fixation of host bone to graft bone. With the stable osseous graft base, the hyaline cartilage portion of the allograft can survive and function for 25 years or more.

The purpose of this study was to ascertain the radiographic results of the modified extended trochanteric sliding osteotomy (ETSO), performed by the senior author. The main feature of the ETSO is preservation of the posterior 1cm of greater trochanter and its attached external rotators. Results with this particular osteotomy for revision hip arthroplasty have not been previously reported.

We reviewed forty-eight ETSOs in forty-six patients that underwent revision hip arthroplasty from March 2000 to March 2006. Nineteen osteotomies were for femoral revision alone, and twenty-nine osteotomies were performed for femoral and acetabular revision. All but six (12.5%) had cortical strut augmentation of the osteotomy. The length of the osteotomy, the length of distal fit, the number of wires used were recorded and their relation to union of the osteotomy and femoral stem loosening were investigated.

The rate of ETSO union in this study was 91.3%. Four osteotomies were not united and this was associated with femoral stem subsidence and loosening requiring femoral stem revision in three cases. The rate of femoral stem loosening requiring revision was 8.3%. The length of the osteotomy did not correlate with femoral stem loosening, but a distal fit of less than 9cm was highly significant(p=0.001) with regards to loosening. The use of cortical struts was not protective against osteotomy non-union or femoral stem loosening. Osteotomy union was shown to be dependant on a well fixed (p< 0.0001) and stable stem (p< 0.0001). Three patients dislocated postoperatively (6.5%), and only one of these required revision surgery.

The modified extended trochanteric osteotomy has a low rate of dislocation and a reliable rate of union. We have shown that a well fixed and stable stem is critical to successfully obtaining union of the osteotomy.

We reviewed and discussed the results of one hundred and fifty-five proximal femoral allografts for revision total hip replacement at an average of eleven years (range , five to twenty years).We looked at graft survivorship, functional results, radiographic assessment and complications. We concluded that this is an excellent technique for restoration of bone stock in the multiplied revised hip.

To review the results of revision hip replacement with use of a proximal femoral allograft (PFA) to restore femoral bone stock.

Between 1983 and 1998 a PFA – prosthetic composite was used to revise two hundred and twenty-seven hips in two hundred and ten patients. Of these two hundred and ten revisions involved an allograft longer than 8 cm. The average age of the patients at the time of revision was sixty-six years. The average number of previous total hip replacements was 2.2. Each patient was assigned a SF-12 score and a Short WOMAC Score. Radiographic assessment for trochanteric union, allograft-host union, component stability, graft fracture and resorption was performed.

At an average of 11.2 years ( range, five to twenty years) after the revision, one hundred and eighty-five patients were alive, twenty-five patients had died and thirty were unavailable for follow-up. SF-12 and short WOMAC scores are still being calculated at the time of abstract submission. 4.4% of hips failed due to infection with 50% being successfully revised. Aseptic loosening of the construct occurred in 3.9% and 78% of these were revised at the time of follow-up. Nonunion of the allograft-host junction occurred in 4.8% and dislocation in 8.4%. Success was defined as a stable implant and no need for additional surgery at the time of follow-up. Success was noted in 84% of available cases.

At an average of eleven years revision hip arthroplasties with a PFA are performing very well. This technique remains an excellent alternative when confronted with femoral bone loss in the revision hip setting.

This is a retrospective study of fifty nine hips in fourty nine patients with a previous total hip replacement for developmental dysplasia of the hip who underwent a revision arthroplasty of the hip. Fifty three patients were available for follow up. Radiographs and charts were reviewed and functional outcome scores were obtained in order to determine if a correlation existed between cup position and functional outcome and survivorship. Cup height was found to be a statistically significant predictor for functional outcome and cup survivorship.

To determine if cup height, lateralization or angle are correlated with functional outcome or survivorship in revision total hip replacement (THR) in patients with a previous THR for developmental dysplasia of the hip (DDH).

There is a paucity of literature correlating functional outcome with cup position in revision THR.

Cup height was found to have a statistically significant (p< 0.05) correlation with Harris Hip, SF36, and WOMAC functional scores. High hip centers correlated with worse scores. In addition, patients with hip centers less than 3.5 cm above the radiographic tear drop had a statistically significant improvement in cup survivorship compared to those with higher hip centers.

A retrospective investigation of forty-nine sequential patients (fifty-nine hips) previously diagnosed with DDH who underwent revision THR at our center between 1984 and 2000 was performed. Forty-three patients (fifty-three hips) were available for survivorship analysis and thirty-five patients (forty-five hips) were available for functional analysis. The mean follow up was one hundred and eighteen months (range 36–230). Three independent variables identified apriori as possible correlates were cup height, lateralization and angle as measured on the AP radiographs. Functional outcome measurement consisted of the Harris Hip, SF36 and WOMAC questionnaires. Linear regression analysis and Kaplan-Meier curves were used to determine if any of the variables correlated with functional outcome or survivorship.

Restoration of hip center height to as close to the radiographic tear drop as possible improves functional outcome. Placement of the cup to within 3.5 cm of the tear drop improves cup survivorship.