The Influence of Femoral Internal Rotation on Patellar Tracking in Total Knee Arthroplasty Using Gap Technique

Background@#Femoral internal rotation in total knee arthroplasty (TKA) is well known as one of the main causes of patellar maltracking. Although femoral internal rotation in TKA is considered unacceptable due to the risk of patellar maltracking, it is sometimes required for ligament balancing. We evaluated the influence of femoral internal rotation on patellar tracking in TKA performed using the gap technique. @*Methods@#From April 2008 to May 2018, 1,612 cases of TKA were done. Among them, 245 cases of TKA for osteoarthritis were followed up for at least 1 year and included in this study. We compared patellar tracking in two groups; group I consisted of 99 cases whose femoral rotation was less than 0° and group II consisted of 146 cases whose femoral rotation was 3°–5° external rotation. Preoperative femoral rotation was measured with the condylar twist angle (CTA) by using computed tomography. The patella was replaced in all cases. Patellar tracking was evaluated with patellar tilt angle (lateral tilt [+] and medial tilt [–]) in the merchant radiograph. Statistical analysis was done using Mann-Whitney U-test. Clinical assessment was performed using the Knee Society clinical rating system. @*Results@#The preoperative CTA was 5.3° ± 1.6° in group I and 5.4° ± 1.6° in group II, showing no statistically significant difference between groups (p = 0.455). Intraoperative femoral rotation was –0.5° ± 0.8° in group I and 3.9° ± 0.8° in group II when the gap technique was used (p < 0.001). The postoperative patellar tilt angle was –0.4° ± 3.6° in group I and 0.1° ± 4.1° in group II with no statistically significant difference (p = 0.251). @*Conclusions@#Compared with femoral external rotation, femoral internal rotation with ligament balance in TKA was not more associated with patellar maltracking. Therefore, patellar tracking might be related with ligament balance in flexion regardless of the anatomic femoral rotational alignment.

The Influence of Femoral Internal Rotation on Patellar Tracking in Total Knee Arthroplasty Using Gap Technique

Background@#Femoral internal rotation in total knee arthroplasty (TKA) is well known as one of the main causes of patellar maltracking. Although femoral internal rotation in TKA is considered unacceptable due to the risk of patellar maltracking, it is sometimes required for ligament balancing. We evaluated the influence of femoral internal rotation on patellar tracking in TKA performed using the gap technique. @*Methods@#From April 2008 to May 2018, 1,612 cases of TKA were done. Among them, 245 cases of TKA for osteoarthritis were followed up for at least 1 year and included in this study. We compared patellar tracking in two groups; group I consisted of 99 cases whose femoral rotation was less than 0° and group II consisted of 146 cases whose femoral rotation was 3°–5° external rotation. Preoperative femoral rotation was measured with the condylar twist angle (CTA) by using computed tomography. The patella was replaced in all cases. Patellar tracking was evaluated with patellar tilt angle (lateral tilt [+] and medial tilt [–]) in the merchant radiograph. Statistical analysis was done using Mann-Whitney U-test. Clinical assessment was performed using the Knee Society clinical rating system. @*Results@#The preoperative CTA was 5.3° ± 1.6° in group I and 5.4° ± 1.6° in group II, showing no statistically significant difference between groups (p = 0.455). Intraoperative femoral rotation was –0.5° ± 0.8° in group I and 3.9° ± 0.8° in group II when the gap technique was used (p < 0.001). The postoperative patellar tilt angle was –0.4° ± 3.6° in group I and 0.1° ± 4.1° in group II with no statistically significant difference (p = 0.251). @*Conclusions@#Compared with femoral external rotation, femoral internal rotation with ligament balance in TKA was not more associated with patellar maltracking. Therefore, patellar tracking might be related with ligament balance in flexion regardless of the anatomic femoral rotational alignment.

Cement Mantle Thickness at the Bone Cement Interface in Total Knee Arthroplasty: Comparison of PS150 RP and LPS-Flex Knee Implants

PURPOSE: To analyze the thickness of cement mantle at the bone cement interface in knees with closed and open box designs in total knee arthroplasty (TKA). MATERIALS AND METHODS: Eighty cases of TKA were performed from October 2013 to March 2014. The average age of the patients was 68.4 years. All patients were women and they were divided into two groups: group I with a closed box implant (PS150 RP, n=40) and group II with an open box implant (LPS-Flex, n=40). We measured the cement mantle thickness at the bone cement interface from the distal femur and proximal tibia. If the thickness was >1 mm, it was considered an outlier. RESULTS: The mean cement mantle thickness at the interface was 1.4 mm in the distal femur and 0.8 mm in the proximal tibia. The value exceed 1 mm in 40 cases (50%) in the distal femur and in 6 cases (7.5%) in the proximal tibia (p<0.001). The mean cement mantle thickness measured in the distal femur was 1.7 mm in group I and 1.0 mm in group II. The value exceed 1 mm in 32 cases (80%) in group I and in 8 cases (20%) in group II (p<0.000). CONCLUSIONS: The cement mantle at the interface was thicker in the knees with the closed box implant than those with the open box implant in TKA, especially in the distal femoral area. A thick cement mantle at the interface should be avoided because it affects the gap balance. In case of using a closed box implant in TKA, cementing should be performed with extra care.

Causes of Failure after Total Knee Arthroplasty in Osteoarthritis Patients 55 Years of Age or Younger

PURPOSE: To identify the modes of failure after total knee arthroplasty (TKA) in patients >55 years of age and to compare with those >55 years of age in patients who underwent revision TKA. MATERIALS AND METHODS: We retrospectively reviewed 256 revision TKAs among patients who underwent TKA for knee osteoarthritis between January 1992 and December 2012. The causes of TKA failure were analyzed and compared between the groups. RESULTS: Thirty-one revision TKAs were performed in patients 55 years of age at primary TKA. In the < or =55 years of age group, the most common cause of TKA failure was polyethylene wear (45%) followed by infection (26%) and loosening (17%). The interval from primary TKA to revision was 8.6 years (range, 1 to 17 years). There were relatively lower infection rate and higher loosening rate in patients < or =55 years of age, but the difference was not statistically significant. CONCLUSIONS: The main causes of failure after TKA in patients < or =55 years of age were polyethylene wear, infection and loosening, and there was no significant difference in the modes of failure after TKA between the two groups.

The Tourniquet Pressure 200 mmHg for Total Knee Arthroplasty: is it possible? / 대한정형외과연구학회지

PURPOSE: To evaluate the possibility of lowering tourniquet pressure to 200 mmHg during total knee arthroplasty (TKA) by pressing the femoral artery. Lowering the toniquette pressure can attribute to minimize the soft tissue damage and pain after the operation. MATERIALS AND METHODS: We analyzed patients who had TKA from Sep 16th, 2010 to Mar 3rd, 2011. Among them, 35 patients (test I) had operations on both knees, and 50 patients (test II) underwent operation on one knee. We excluded the patients who had a previous operation, infection, or bleeding tendency. We put a cotton roll at the antero-medial side of the thigh just under the tourniquet in order to apply more pressure on the femoral artery that is scanned by ultrasonography. We scored 0 on non-bleeding, 1 on bleeding that did not affect the operation, and 2 on bleeding which disturbed the operation. RESULTS: In test I, the group which applied 200 mmHg with local pressure, 24 patients (68.6%) scored 0, 9 patients (25.7%) scored 1, and two patients (5.7%) scored 2. In the other group used pressure 250 mmHg, however, 31 patients (88.6%) scored 0, 4 patients (11.4%) scored 1, and no one scored 2 (p=0.039). Totally, in the 200 mmHg group with local pressure, 33 patients had no problem in surgery, and only for 2 patients (5.7%), we had to increase pressure. For the patients with 250 mmHg, however, we had to increase pressure on nobody (0%). In test II, in the group which had operation on one knee with 200 mmHg with local pressure, 14 patients scored 0, 8 patients scored 1, and one patient scored 2. Also in the 250 mmHg group, 24 patients scored 0, 2 patients scored 1, and one patient scored 2. (p=1.000). Overall results demonstrate no differences in bleeding that disturb operations statistically. CONCLUSION: Even with a little more bleeding compared to the 250 mmHg group, 94.8% of patients can have operation with no bleeding problems by using a cotton roll and the pressure 200 mmHg. For successful operations, there is no difference between groups using 250 mmHg and 200 mmHg with local pressure on femoral artery.

Causes of Femoral Component Radiologic Abnormality After Total Knee Arthroplasty Using Legacy Posterior Stabilized-Flex Prosthesis / 대한정형외과연구학회지

PURPOSE: We analyzed the causative factors of femoral component radiologic abnormality after total knee arthroplasty (TKA) using a Legacy Posterior Stabilized (LPS)-Flex prosthesis. MATERIALS AND METHODS: 140 cases of TKA using LPS-Flex and 140 cases of Vanguard from Jan 2008 to June 2010 were analyzed and radiographic abnormalities around the femoral stems were compared. Secondly, TKA using LPS-Flex was divided into two groups according to the posterior femoral cutting technique, which were single cutting method and additional cutting method. Accuracy of the femoral posterior resection was compared. RESULTS: Radiographically, anterior radiolucent line was found in eight cases with LPS-Flex but no case with Vanguard. Posterior overhang more than 30% was found in ten cases in both groups. Posterior bone defect more than 50% was found in 23 and seven cases respectively. Anterior radiolucent line and posterior bone defect were observed significantly more in LPS-Flex. In the second study, we found femoral posterior bone defect in 20 cases with additional cutting method which was caused by flexion of the femoral box-cutting guide. CONCLUSION: Posterior bone defect from LPS-Flex was caused by inappropriate resection due to flexion of the box cutting guide. Single cutting method should be adopted for more accurate posterior femoral cutting.

Total Knee Arthroplasty after Failed Unicompartmental Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: To identify the causes of failure after unicompartmental knee arthroplasty (UKA), and to evaluate considerations for surgical procedures and the results of revision total knee arthroplasty (TKA) performed after failure of UKA. MATERIALS AND METHODS: Eight hundreds and fifty-two cases of UKA were performed from January 2002 to June 2011. Forty-seven cases of failures after UKA were analyzed for the cause of the failures, and thirty-five cases of revision TKA after failure were analyzed for the operative findings and surgical technique. The clinical results were measured for thirty cases which were followed-up on at least two years after TKA. The mean duration of follow-up was four years and one month after revision TKA and the mean patient age at the time of surgery was sixty-five years. RESULTS: For the cause of failures after UKA, there were twenty-two cases of early loosening of prosthesis, seventeen cases of simple mobile bearing dislocation, five cases of infection, one case of fracture of medial tibial condyle and two cases of unknown origin pain. In operative findings of thirty-five cases of TKA after failed UKA, there were twenty-seven cases of bone defect requiring treatment and the mean thickness of the defect was 10.6 mm. For the treatment of bone defect, there were five cases of autogenous bone graft, twenty-one cases of metal blocks, and one case of autogenous bone graft with metal block. The stem was used in tibial implants for nineteen cases, and one case of use in tibial and femoral implants. For thirty cases where follow-ups were possible at least two years after operation, the mean knee score was improved from 68.2 to 85.2 and the mean knee function score was improved from 67.7 to 78.0 at the last follow-up, respectively. The mean range of knee motion was 107.2degrees pre-operatively, which was recovered to 120.7degrees after the operation. The mean tibiofemoral angle was changed from 1.7degrees of valgus to 5.2degrees of valgus. CONCLUSION: As shown in this study, the tibial bone defect was the most important problem in revision TKA after failure of UKA. Therefore, proper indication and accurate surgical technique using autogenous bone graft, metal block and stemmed implants would be able to achieve satisfactory results in revision TKA after failure of UKA.

Relationship between the Tourniquet Pressure and the Amount of Subcutaneous Bleeding after Total Knee Replacement

PURPOSE: We wanted to evaluate the post-operative amount of subcutaneous bleeding according to the tourniquet pressure during total knee replacement. MATERIALS AND METHODS: We analyzed 136 patients who had undergone total knee replacement at our hospital from March 4th, 2010 to September 16th, 2010. A tourniquet pressure of 250 mm Hg was applied to 69 patients (group I) and a tourniquet pressure of 320 mm Hg was applied to the other 67 patients (group II). Subcutaneous bleeding was evaluated on the 3rd and 6th days after the operations. All of the total knee replacements were performed by a single surgeon. RESULTS: Among the group I patients, subcutaneous bleeding was seen in just 2 patients, yet among the group II patients, there were 32 patients with subcutaneous bleeding on the 3rd day and 33 patients with subcutaneous bleeding on the 6th day. According to the multiple regression analysis, there were no significant differences in ages, the tourniquet time and the orders between the two groups. Group 1 had significantly less subcutaneous bleeding than did group II on the 3rd and 6th days after the operations (p=0.001). CONCLUSION: There was a significant difference of the amount of subcutaneous bleeding amount according to the tourniquet pressure. We were able to decrease the post-operative amount of subcutaneous bleeding after total knee replacement by lowering the tourniquet pressure to 250 mm Hg.

The Analysis of Risk Factors in No Thumb Test in Total Knee Arthroplasty

BACKGROUND: We would like to analyze the risk factors of no thumb test among knee alignment tests during total knee arthroplasty surgery. METHODS: The 156 cases of total knee arthroplasty by an operator from October 2009 to April 2010 were analyzed according to preoperative indicators including body weight, height, degree of varus deformity, and patella subluxation and surgical indicators such as pre-osteotomy patella thickness, degree of patella degeneration, no thumb test which was evaluated after medial prepatella incision and before bone resection (1st test), no thumb test which was evaluated with corrective valgus stress (2nd test, J test), and the kind of prosthesis. We comparatively analyzed indicators affecting no thumb test (3rd test). RESULTS: There was no relation between age, sex, and body weight and no thumb test (3rd test). Patellar sulcus angle (p = 0.795), patellar congruence angle (p = 0.276) and preoperative mechanical axis showed no relationship. The 1st no thumb test (p = 0.007) and 2nd test (p = 0.002) showed significant relation with the 3rd no thumb test. Among surgical indicators, pre-osteotomy patella thickness (p = 0.275) and degeneration of patella (p = 0.320) were not relevant but post-osteotomy patellar thickness (p = 0.002) was relevant to no thumb test (3rd test). According to prosthesis, there was no significance with Nexgen (p = 0.575). However, there was significant correlation between Scorpio (p = 0.011), Vanguard (p = 0.049) and no thumb test (3rd test). Especially, Scorpio had a tendency to dislocate the patella, but Vanguard to stabilize the patella. CONCLUSIONS: No thumb test (3rd test) is correlated positively with 1st test, 2nd test, and post-osteotomy patella thickness. Therefore, the more patella osteotomy and the prosthesis with high affinity to patellofemoral alignment would be required for correct patella alignment.

Comparative Study for the Results of Unicompartmental Knee Arthroplasty in Patients Younger and Older than 60 Years of Age / 대한정형외과학회잡지

PURPOSE: We wanted to assess the relations between age and the outcome of unicompartmental knee arthroplasty (UKA) based on a comparative study of UKA patients younger than 60 years and UKA patients older than 60 years of age. MATERIALS AND METHODS: Among the patients who underwent a UKA between January 2002 and June 2003, 230 cases (the group of patients with ages under sixty consisted of 89 knees - group I, and the group of patients with ages over sixty consisted of 141 knees - group II) were followed up for at least 5 years after the operation. Clinical assessments were made using the Knee Society Score (KSS) rating system. RESULTS: The average KSS knee and function scores improved from 54.2 and 57.1 preoperatively to 87.3 and 85.2 at the last follow-up in group I, and from 54.7 and 54.3 to 89.5 and 81.7 in group II, respectively. The mean range of knee motion also improved from 129.4degrees to 132.9degrees in group I and from 126.8degrees to 133.2degrees in group II, respectively. There were 5 cases of failed UKAs in each group, and the survival rate of the implant at 5 years was 94.7% in group I and 96.6% in group II. CONCLUSION: The clinical results of UKA were satisfactory in both age groups. Group I had better results on the knee function score at the last follow-up, but there was no significant difference between both age groups. UKA can be a one of the reliable methods for the treatment of osteoarthritis in patients younger than 60 years of age.

Total Knee Arthroplasty using a Medial Pivot Knee: Minimum 2-year Follow-up Results

PURPOSE: To evaluate short-term clinical and radiologic outcomes after Advance(R) total knee arthroplasty (TKA). MATERIALS AND METHODS: We evaluated 226 patients who underwent 348 TKAs using medial pivot knees and who were followed up for more than 2 years. The average follow-up period was 40.6 months. We evaluated clinical outcomes based on range of motion (ROM), Knee Society score, and functional score. Radiographic outcomesand complications were also recorded. RESULTS: The average flexion contracture improved from a preoperative value of 6.2degrees to a last follow-up value of 1.3degrees. The average knee flexion was 114degrees preoperatively and 109degrees at last follow-up. The average knee and functional scores were 43.1 and 50.8, respectively, in the preoperative period and 86.2 and 77.9, respectively, in the postoperative period. Complications included 3 avulsion fractures of the medial collateral ligament, 2 delayed infections, 2 periprosthetic fractures, and 1 patellar dislocation. CONCLUSION: The short-term clinical results associated with medial pivot TKA were acceptable. However, more experience and long-term follow-up will be necessary to better determine the efficacy of this procedure.

Ceramic on Ceramic Hybrid Type Total Hip Arthroplasty in Patients with more than 65 years of Age -Minimum 5-year Follow-up Results

Purpose: This study examined the minimum five-year results of hybrid type total hip arthroplasty (THA) with ceramic-on-ceramic articulation and femoral stem fixation using cement in patients older than 65 years. Materials and Methods: From February 1999 to November 2002, a hybrid type THA with ceramic-on-ceramic articulation and femoral stem fixation using cement were performed in 47 patients (47 hips) older than 65 years of age. Among the 47 patients, 29 patients were followed up for more than 5 years. The mean age of these patients was 68.9 years (65~73years). The mean follow-up period was 74.6 months (61~107 months). The postoperative diagnosis included AVN of the femoral head in 21 hips, Osteoarthritis in 2 hips, rhematoid arhthritis in 1 hip, femoral neck fracture in 4 hips and Tuberculosis in 1 hip. The clinical results were analyzed retrospectively by the Harris hip score (HHS), hip and thigh pain, and radiologically by the level of osteolysis around acetabular cup and femoral stem, bone reabsorption by stress shielding, instability, acetabular and femoral stem anteversion, acetabular inclination and the femoral stem fixation site. Results: After surgery, the overall HHS improved from 56.3 +/- 1.4 to 92.3 +/- 1.1 points (p=0.013). Excellent and good results were obtained in 21 (72.4%) and 8 hips (27.6%), respectively. There was no case of thigh pain. Radiologically, there was no acetabular and femoral component osteolysis. Absorption by stress shielding was observed in 6 cases (20.7%) with an acetabular cup and 3 cases (10.3%) with a femoral stem. Bony stability was observed in all cases treated with an acetabular cup and possible loosening in 1 case (3.4%) treated with a femoral stem. Acetabular and femoral stem anteversion was 18.4degrees+/- 1.1 and 13.1degrees+/- 0.9 respectively. Acetabular inclination was 41.5degrees+/- 1.3. The femoral stem was inserted centrally in all cases. Complications included posterior dislocation of 1 hip (3.4%) and periprosthetic fracture of the femur in 1 hip (3.4%). There was no fracture of the ceramic component Conclusion: The mid-term results of hybrid type THA with ceramic-on-ceramic articulation and femoral stem fixation using cement were effective both clinically and radiologically in patients older than 65 years.

Analysis of Risk Factors Affecting Degeneration of the Acetabular Cartilage after Bipolar Hemiarthroplasty

PURPOSE: This study attempted to investigate the rate of acetabular cartilage wear, as well as the risk factors that are related to degeneration, for patients who were diagnosed with femur neck or intertrochanteric fracture and who underwent bipolar hemiarthroplasty. MATERIALS AND METHODS: 34 patients who were diagnosed with femur neck or intertrochanteric fracture and who underwent bipolar hemiarthroplasty were selected as the study subjects, and they were followed up for more than 2years. We examined potential relationships between the degeneration of acetabular cartilage and the various risk factors by comparing radiographs taken before and after operations. RESULTS: After bipolar hemiarthroplasty, the average degenerative change in the acetabular cartilage was 0.20 mm/yr. Specifically, the average appeared significantly different according to gender (p=0.039, Male: 0.26 mm/yr, Female: 0.19 mm/yr), age (p=0.02, the under 70-year olds: 0.29 mm/yr, the upper 70-year olds: 0.13 mm/yr), the life style, (p=0.037, the stand-up life style: 0.18 mm/yr, the sit-down life style: 0.24 mm/yr), (ED note: stand up and sit down made no sense.) and using femoral stem cementing (p=0.237, cement: 0.22 mm/yr, non-cement: 0.21 mm/yr). The bone mineral density score (p=0.254), activity score (p=0.041), HHS (p=0.027) and femoral stem alignment (p=0.438) were shown to be -3.7, 3.2, 87 and varus 1 degree for people with less than average degeneration of the acetabular cartilage and -3.9, 4.3, 75 and varus 2 degrees for people with more than average degeneration of the acetabular cartilage, respectively. CONCLUSION: The results showed no significant relationship between degeneration of the acetabular cartilage and patient gender, the presence of osteoporosis and using femoral stem cement. The degeneration of acetabular cartilage was faster for young patients, for patients with a sit-down life style, for a higher activity score or for a lower HHS. It is strongly recommended for surgeons to consider the patients' various conditions such as age, activity and a sit-down lifestyle when deciding between hemiarthroplasty and total hip arthroplasty.

Mortality and Activity after Hip Fracture: A Prospective Study / 대한정형외과학회잡지

PURPOSE: This prospective study conducted to estimate mortality and activity of hip fracture among persons over 50 years of age, in Jeju island, Korea during the year 2002. MATERIALS AND METHODS: One hundred forty-nine patients among 150 patients over 50 years of age who lived in Jeju island and sustained a femoral neck or intertrochanteric fracture during the year 2002 were followed-up for average 2 years. Standardized annual mortality ratio was calculated and comparison was made between hip fracture patients and general population in Jeju island. RESULTS: One hundred forty-nine patient were followed-up (35 in men, 114 in women). The mean age of patients was 77.4 years (range 50-98 years). Mortality at 2 years (range, 1.6-2.6 years) was 28.2% (42 patients), mortality at 1 year was 16.8% (25 patients) and mortality at 6 months was 12.1% (18 patients). Patients who were classified as poor (Halpin grade III and IV) increased in number from preoperative 11 patients to postoperative 37 patients. CONCLUSION: Considering 28.2% of high mortality and 25.2% of poor activity who can not do outside activity at average 2 year follow up, the hip fracture is life threatening risk factor of elderly. Prevention falling and hip fracture risk is needed.

Osteoprotegerin and Osteoprotegerin Ligand Expression in the Periprosthetic Tissue of Failed Hip Prosthesis / 대한정형외과학회잡지

PURPOSE: To investigate the pathogenesis of articular prosthesis osteolysis, and to clarify the role of OPG, RANKL and RANK on osteolysis in aseptic loosening of hip prostheses. MATERIALS AND METHODS: We examined the mRNAs of OPG, RANKL and RANK from cultured peripheral mononuclear cells and the tissue surrounding failed hip prostheses by RT-PCR and gel electrophoresis and performed immunohistochemistry for RANKL and RANK in the periprosthetic tissue of revised hip replacement therapy. RESULTS: RANKL was detected in 32% and RANK was detected in 20% of the periprosthetic tissues of failed hip prostheses. Proliferative responses of cultured PBMCs occurred in cells with the titanium, cobalt and LPS, and highest response was observed in cells with cobalt particles. The mRNAs of RANKL and OPG were expressed in the periprosthetic tissues of loosened hip prostheses, but RANK mRNA was not detected. OPG mRNA was not detected in cultured PBMCs with any particles, RANKL mRNA was detected in cultured PBMCs with titanium and cobalt particles by RT-PCR, and RANK mRNA was detected in PBMCs with cobalt particles, but not with titanium. CONCLUSION: Osteolysis around the failed hip prosthesis may be related to activation of the OPG-ANKLRANK system. It is suggested that OPG, RANKL and RANK are major mediators of osteolysis in failed hip prosthesis.

Clinical and Radiological Results of Revision Acetabular Arthroplasty using an Acetabular Roof Reinforcement Ring / 대한정형외과학회잡지

PURPOSE: We evaluated the clinical and radiological results of acetabular reconstructions using an acetabular roof reinforcement ring (ARR). MATERIALS AND METHODS: From May 1993 to November 1999, 18 hips revised with ARR were evaluated. The mean age at operation was 53 years. The average follow-up period was 51 months (24-94 months). Acetabular defects were classified based on the AAOS classification system. There was one case of type IIA defect, six cases of type IIB defect, ten cases of type III defect and one case of type IV defect. All were treated with morselized allografts and autografts, and three were reconstructed with additional structural autografts. RESULTS: The average Harris hip score improved from 54 preoperatively to 76 postoperatively, but five patients complained of intermittent hip pain. On the last follow-up radiographs, the bone grafts were united and remodeled in all cases, but only partial resorption was observed in two hips. We found evidence of osteolysis in four hips and observed cup migration in three hips. Three hips, in which Muller rings were used, were re-revised during the follow-up period. CONCLUSION: Acetabular reconstruction using ARR led to good clinical and radiological results, but a relative high rate of rerevision was shown in the cases fitted with the Muller ring. Appropriate ARR should be used depending on the extent of the acetabular defect.

Reconstruction of Acetabular Defect Using Block Bone Graft in Primary Cementless THA / 대한정형외과학회잡지

PURPOSE: To evaluate the results of acetabular reconstruction using block bone graft in primary cementless total hip arthroplasty (THA). MATERIALS AND METHODS: Twenty-four primary THA, in which a block bone graft was used for the reconstruction of the acetabular bone defect, were performed between May 1989 and July 1999, and followed for more than 2 years. Clinical results were assessed using the Harriship score. Radiologically, we observed the graft coverage of the acetabular component, union, resorption of the graft, change in the positionof the hip center, linear wear rate of the polyethylene insert, osteolysis around the acetabulum and evidence of loosening of the acetabularcomponent. RESULTS: The mean Harris hip score improved from 65 points preoperatively to 86 points postoperatively. The coverage of the acetabular components by graft was less than 50% in all hips. Union of the grafted bone took 8 months (5-15 months) on average. During the follow-up period, revisions were required in 3 hips (12%). The causes of the revision were osteolysis. CONCLUSION: Non-structural block bone grafting seems to be a reliable method for restoring acetabular bone stock in primary THA usinga cementless acetabular component.