Outcomes of computer-assisted peri-acetabular osteotomy compared with conventional osteotomy in hip dysplasia.

AIM OF THE STUDY: To compare the outcomes after computer-assisted peri-acetabular osteotomy (PAO) and conventional PAO performed for hip dysplasia (DDH). METHODS: Ninety-one patients (98 hips) were enrolled in this study. In each case, DDH was treated with either conventional PAO, in which the angle and direction of the osteotomy was determined by intra-operative X-ray examination, or with computer-assisted PAO, which used the 3D navigation system. Forty hips underwent conventional PAO and 58 hips underwent computer-assisted PAO. RESULTS: Japanese Orthopaedic Association hip scores improved significantly from 70.0 points pre-operatively to 90.7 points post-operatively in patients with conventional PAO, and from 74.5 points pre-operatively to 94.2 points post-operatively in patients with computer-assisted PAO. In all patients with computer-assisted PAO, the post-operative AHI and VCA angle were within the radiographic target zone. Some patients with conventional PAO had post-operative AHI and VCA angle outside of the target zone. We performed total hip arthroplasty (THA) on five of the 98 PAO hips (5.1%) after an average follow-up period of 5.4 years. None of 58 hips (0%) with computer-assisted PAO was revised. DISCUSSION: Computer-assisted PAO enabled intra-operative confirmation of osteotomy sites, and the position of the osteotomized bone fragment could be confirmed in real time. Adequate anterior and lateral coverage of the femoral head in patients with computer-assisted PAO resulted in no need for early conversion to THA, in contrast to conventional PAO. CONCLUSION: Computer-assisted PAO not only improved accuracy and safety but also achieved sufficient anterior and lateral displacement to prevent the progression of DDH.

Radiolucency around highly porous sockets and hydroxyapatite-coated porous sockets in total hip arthroplasty for hip dysplasia.

Studies over the past decade have reported that the use of highly porous sockets in total hip arthroplasty (THA) results in osseointegration and long-term implant stability. However, some reports have raised concerns regarding radiographic evidence of poor osseointegration with features of fibrous tissue ingrowth. The purpose of this study was to compare clinical and radiographic assessments of highly porous sockets with those of hydroxyapatite (HA)-coated porous sockets in THA for hip dysplasia (DDH) at least 1 year after surgery. A total of 127 patients (136 hips) were recruited for the study. Of these, 94 patients (101 hips) received highly porous sockets with clustered screws, while 33 patients (35 hips) received HA-coated porous sockets with clustered screws. There was no difference in clinical outcomes between the two types of sockets. All HA-coated porous sockets were radiographically stable, without radiolucent lines. Fifteen hips had radiolucent lines in two or three DeLee and Charnley zones, accompanied by sclerotic lines along the circumferences of the highly porous sockets. A significant difference in the height of the preoperative osteophyte of the anterior acetabular wall was observed between 86 hips with one or no radiolucent lines and 15 hips with two or three radiolucent lines. In cases of DDH with atrophic bone remodeling pattern, highly porous sockets with multiple screws may be used, while HA-coated porous sockets with clustered screws result in better sealing of the bone-component interface.

Acetabular reconstruction with the Kerboull-type plate at mid-term follow-up: survivorship analysis and prognostic factors for loosening.

INTRODUCTION: Successful reconstruction during total hip arthroplasty for acetabular bone defects remains challenging. The purpose of our study was to evaluate clinical and radiographic results and performed a survivorship analysis for patients with acetabular bone loss undergoing total hip arthroplasty (THA) or revision THA using Kerboull-type acetabular reinforcement device(KT plate). Additionally, some independent prognostic factors for radiographic failure were identified. METHODS: A retrospective cohort study was conducted. Thirty patients (36 hips) were available for follow-up examination between 1997 and 2012, with a mean follow-up period of 10 years. We evaluated clinical and radiographic results. The mean patient age at the time of the operation was 66 years. RESULTS: Failure occurred in 6 cases, and further revisions were required for 2 hips. With failure for any reason as an endpoint, the cumulative survival at 10 years was 85%. Survival analysis at 10 years with failure as the endpoint revealed that the inclination angle of the KT plate ≤ 45° group showed higher survivorship than the inclination angle > 45° group (95.8 vs. 63.6%, P = 0.0047). CONCLUSIONS: With a mean follow-up of 10 years, the clinical and radiographic outcomes were satisfactory. While this study group was small, the results suggest that prosthesis longevity may be improved by setting the inclination angle of this reinforcement device at ≤ 45°.

Preoperative Planning and Operative Techniques of the Shorter Tapered Stem Compared to the Metaphyseal Fit Stem in Cementless Total Hip Arthroplasty.

BACKGROUND: In order to prevent postoperative dislocation due to prosthetic impingement as a result of total hip arthroplasty (THA), the combined anteversion (CA) theory, which combines the anteversion of the femoral stem and the acetabular socket, has been revised in recent years. Particularly, it is necessary to keep CA within the target zone. METHODS: The aim of this study was to investigate whether postoperative CA can be kept within the target zone while using the operative technique which prepares the socket first in cementless THA, by estimating the anteversion of the metaphyseal fit stem or the shorter, tapered wedge stem using preoperative 3-dimensional computerized planning, and by adjusting the anteversion of the socket using a navigation system that considers CA. One hundred fourteen patients (118 hips) were recruited for the study. RESULTS: Postoperative CA in THA using the metaphyseal fit stem was kept within the target zone for 56 of the 60 hips (93.3%). Using the shorter, tapered wedge stem, 49 of the 58 hips (84.4%) were within the target zone. No postoperative dislocations were observed in any hips. CONCLUSION: We found that the metaphyseal fit stem worked better than the shorter, tapered wedge stem in terms of meeting the planned CA. The shorter, tapered wedge stems were flexible in rotation according to the anatomical configuration of the proximal femur. Therefore, the stem could be placed second with the metaphyseal fit stem, but we recommend placing the stem first with the shorter, tapered wedge stem.

Preoperative planning and postoperative evaluation of total hip arthroplasty that takes combined anteversion.

The purpose of this study was to investigate whether postoperative combined anteversion (CA) can be kept within the safe zone while using cementless total hip arthroplasty (THA) using the operative technique which prepares the socket first for developmental dysplasia of the hip (DDH), by estimating the anteversion of the metaphyseal fit stem using preoperative three-dimensional (3D) computerized planning and by adjusting the anteversion of the socket using a navigation system that considers CA. Our subjects were 65 patients (65 hips) that had undergone cementless THA for DDH that could be observed for 1 year or more. Clinical assessments were made using the Japanese Orthopaedic Association's (JOA) hip score. For a radiological evaluation, we investigated 3D-planned stem versions, postoperative stem versions, preoperative and postoperative CA, and the relationship between CA and dislocation tendencies with temporary intraoperative reductions. JOA hip scores improved from 52.3 ± 11.4 points to 88.9 ± 8.6 points. CT evaluations revealed that 3D-planned stem versions were strongly correlated with postoperative stem versions (r = 0.80; p < 0.01). Preoperative CA was 50.5° ± 7.2°, and postoperative CA was 41.3° ± 8.6°. Postoperative CA was kept within the safe zone in 61 hips. No intraoperative dislocation tendencies were observed in any hips. By estimating the anteversion of the cementless metaphyseal fit stem using 3D planning preoperatively and adjusting the angle of anteversion of the socket using a navigation system that considers CA intraoperatively, postoperative CA can very frequently be kept within the safe zone, even with cementless THA using the operative technique which prepares the socket first for DDH.

Long term results with the interlocking uncemented long stem in revision hip arthroplasty: a mean 15-year follow-up.

Stem fixation is difficult to achieve in severe proximal bone loss in revision hip surgery. In this study, we sought to present the results of distally-locked stem with screws (HUCKESTEP HIP stem) in 21 revision hips with mean follow-up period of 15 years. The preoperative mean Japanese Orthopaedic Association hip score had improved from 54 to 75 points. Further revisions were required for 2 stems, in one because of infection and the other because of screws fracture and subsidence. With removal of the stem for any reason as an end-point, the cumulative survival at 15 years was 90.4%. While this study had small number, the use of this interlocking stem for revision hips with extensive proximal bone defects provided satisfactory 15-year clinical and radiographic results.

Mid-term clinical and radiographic outcomes of porous tantalum modular acetabular components for hip dysplasia.

It is still challenging to perform successful cementless cup fixation during total hip arthroplasty for hip dysplasia. In this multicenter study we evaluated the clinical results of porous tantalum modular acetabular cups (TM cups) in 45 dysplastic hips with a mean follow-up period of 9.8 years. The mean Japanese Orthopaedic Association hip score improved from 48.2 preoperatively to 92.1 at the most recent follow-up. All of the cups were radiographically stable with no evidence of progressive radiolucencies or osteolysis regardless of bone grafting. Sixteen hips with bone grafts showed the integration of grafted bone without any radiolucencies. There were no revisions of TM cups. The use of TM cups for dysplastic hips provided satisfactory 10-year clinical and radiographic results.

Anterior coverage after eccentric rotational acetabular osteotomy for the treatment of developmental dysplasia of the hip.

BACKGROUND: In periacetabular osteotomy for the treatment of developmental dysplasia of the hip, impairments in ADL due to limitations in hip flexion can occur when anterior displacement is added to lateral displacement in order to obtain sufficient femoral head coverage. This study was conducted to determine, by the range of motion (ROM) simulation based on CT images, the minimum angle of hip flexion and internal rotation at 90° of flexion that is necessary to avoid ADL impairments after eccentric rotational acetabular osteotomy (ERAO) and to estimate the angles of anterior femoral head coverage on plain radiography that enable the above flexion. METHODS: Of 47 hips treated with ERAO at our hospital from December 2007 to May 2012, 27 hips without progressive osteoarthritis which could be CT scanned were examined and included. The mean age at the time of surgery was 40.7 years (SD 1.8). The postoperative follow-up period was 30.2 months (SD 3.6). Two hips were in male patients and 25 hips were in female patients. The disease stage prior to surgery was pre-osteoarthritis in 5 hips, early in 11 hips, and progressive in 11 hips. We checked whether the patients were capable of activities that require deep hip flexion for the evaluation of postoperative ADL. Radiographic examination was performed before and one year after surgery to calculate LCE angle, Sharp angle, AHI, and VCA angle. The angle at which impingement of the displaced fragment of the bone and the femur appeared was measured using 3D CAD software, and the relationship between this angle and the physical findings, ADL impairment, or radiographic findings, were also examined. RESULTS: 22 out of 27 hips that were capable of 116° or more of flexion or 42° or more of internal rotation at 90° of flexion in ROM simulation showed the absence of ADL impairment and a postoperative VCA angle ≤42°, whereas 5 hips with 110° or less of flexion or 40° or less of internal rotation at 90° of flexion in ROM simulation had ADL impairments associated with limitations in hip flexion and a postoperative VCA angle ≥46°. CONCLUSIONS: Anterior and lateral coverage requires a postoperative VCA angle of ≥20° to achieve anterior structural stability and an LCE angle of >25° to obtain adequate superior lateral coverage of the femoral head. A VCA angle ≤42° is required to avoid impingement during deep flexion. A VCA angle ≥46° is a probable risk factor for pincer FAI syndrome after ERAO.

Computer-assisted anteverting eccentric rotational acetabular osteotomy for recurrent posterior dislocation associated with acetabular retroversion: a case report.

BACKGROUND: Acetabular retroversion is a rotatory abnormality of the entire hemipelvis that includes anterior over-coverage and posterior deficiency of the acetabulum, and is associated with pincer-type femoroacetabular impingement and posterior hip instability. Acetabular retroversion is thought to cause posterior dislocation of the hip in athletes due to both the pincer-type femoroacetabular impingement and posterior hip instability. CASE PRESENTATION: A 26-year-old Japanese man had acetabular retroversion that induced recurrent posterior dislocation of his hip due to excessive hip flexion while wakeboarding. We performed anteverting eccentric rotational acetabular osteotomy using preoperative three-dimensional planning and an intraoperative computerized navigation system. Our patient was able to return to sports activities 1 year postoperatively. CONCLUSIONS: Both preoperative three-dimensional surgical planning software and an intraoperative navigation system can provide a highly accurate map for this complicated surgery that simultaneously improves the pincer-type femoroacetabular impingement and posterior deficiency of the acetabulum.

Successful Two-step Correction for Severe Genu Valgum in Ellis-van Creveld Syndrome: A Case Report.

INTRODUCTION: Ellis-van Creveld syndrome (EVC) is a very rare genetic disorder involving a severe, relentlessly progressive genu valgum deformity of the knee and it is usually difficult to correct all of the deformities by elevation of the depressed lateral tibial plateau alone. We are reporting one such case treated using two-step operative technique (first, gradual correction using Taylor spatial frame (TSF) and second, tibia elevation through intra-articular osteotomy). CASE REPORT: We report a case of 10-year-old female with severe genu valgum in EVC using two-step operative technique. First, performing soft tissue release and gradual correction using a TSF. Second, tibia elevation through intra-articular osteotomy resulted in improved joint congruity. At final follow-up, the patient has a good functional result and the Mikulicz line proceeded physiologically to the joint center. CONCLUSION: This two-step technique allowed for the correction of the joint architecture and associated complications are minimal. For severe genu valgum in EVC, joint congruity is improved by the elevation of the anterolateral aspect of the tibia through intra-articular osteotomy. Performing soft tissue release followed by gradual correction allows for correction of the valgus and external rotation deformities without causing neuroparalysis.

Comparison of 10-year clinical wear of annealed and remelted highly cross-linked polyethylene: A propensity-matched cohort study.

No previous studies comparing the clinical wear rates of the two different kinds of cross-linked ultra-high-molecular-weight polyethylene (XLPE), annealed and remelted, are available. We compared the creep and steady wear rates of 36 matched pairs (72 hips in total) adjusting for baseline characteristics with propensity score matching techniques. Zirconia femoral heads with 26-mm diameter were used in all cases. The femoral-head cup penetration was measured digitally on radiographs. Significantly greater creep (p=0.006) was detected in the remelted (0.234mm) than annealed (0.159mm) XLPE. However, no significant difference (p=0.19) was found between the steady wear rates (0.003 and 0.008mm/year, respectively) of the annealed and remelted XLPE. Multiple regression analyses showed that remelted XLPE is significant independent variable (p<0.001) that is positively associated with creep. However, the patient age and body weight, cup size, the liner thickness, cup inclination, follow-up periods, and postoperative Merle d'Aubigné hip score had no significant effects (p>0.05) on the steady wear rates. No patients exhibited above the osteolysis threshold of 0.1mm/year, progressive radiolucencies, osteolysis, or polyethylene fracture. This　propensity-matched cohort study document no significant difference in wear resistant performances of annealed and remelted XLPE over an average period of 10 years.

Molecular detection of cancer cells in saliva from oral and pharyngeal cancer patients.

A key to improve the prognosis of head and neck cancers is an early diagnosis of the disease. No screening method to detect these cancers has been developed yet. Molecular techniques using polymerase chain reaction are a sensitive method to detect a small population of cancer cells among normal cells. We conducted a series of microsatellite analysis to detect cancer cells in saliva from 23 oral and pharyngeal cancer patients. Eight microsatellite markers were selected to test for microsatellite instability (MSI) in the tumor and saliva samples. Of 23 samples, 5 (22%) had MSI in the tumor samples. In 4 of 5 (80%) MSI positive samples, we detected the identical MSI in saliva. The possibility of the molecular screening and molecular follow-up is discussed.