Ten-year survival and complications of total knee arthroplasty for osteoarthritis secondary to trauma or surgery: A French multicentre study of 263 patients.

BACKGROUND: Previous surgical procedures raise technical challenges in performing total knee arthroplasty (TKA) and may affect TKA outcomes. Survival rates of TKA done after trauma or surgery to the knee have not been accurately determined in large populations. The objectives of this retrospective study in 263 patients with TKA after knee trauma or surgery and a follow-up of 10 years were to assess survival, functional outcomes, and the nature and frequency of complications. HYPOTHESIS: Knee trauma or surgery before TKA increases the risk of complications and decreases implant survival. MATERIAL AND METHODS: Two hundred and sixty-three patients (122 [47%] females and 141 [53%] males) underwent TKA between 2005 and 2009 at nine centres in France. Mean age at surgery was 61 years. The patients had knee osteoarthritis secondary to a fracture (n=66), osteotomy (n=131), or ligament injury (n=66). Mean time from trauma or surgery to TKA was 145 months (range, 72-219 months). RESULTS: Major complications were infection (n=12, 4.5%), skin problems (n=8, 3%), and stiffness (n=8, 3%). Ten-year survival to implant exchange for any reason was 89%±2.8%. Flexion range increased by 2.5°±17° (p=0.02) to a mean of 110° (range, 30° to 140°); extension range increased by 4°±7° (p<0.001) to a mean of -1.19 (range, -20° to 0°). Of the 263 patients, 157 (60%) reported little or no pain at last follow-up. Mean postoperative hip-knee-ankle angle was 179°±3.2° (range, 171°-188°). CONCLUSION: TKA performed after knee injury or surgery carries a risk of specific complications (infection, skin problems, and stiffness) and may have a lower survival rate compared to primary TKA. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Aluminum and bone: Review of new clinical circumstances associated with Al(3+) deposition in the calcified matrix of bone.

Several decades ago, aluminum encephalopathy associated with osteomalacia has been recognized as the major complication of chronic renal failure in dialyzed patients. Removal of aluminum from the dialysate has led to a disappearance of the disease. However, aluminum deposit occurs in the hydroxyapatite of the bone matrix in some clinical circumstances that are presented in this review. We have encountered aluminum in bone in patients with an increased intestinal permeability (coeliac disease), or in the case of prolonged administration of aluminum anti-acid drugs. A colocalisation of aluminum with iron was also noted in cases of hemochromatosis and sickle cell anemia. Aluminium was also identified in a series of patients with exostosis, a frequent benign bone tumor. Corrosion of prosthetic implants composed of grade V titanium (TA6V is an alloy containing 6% aluminum and 4% vanadium) was also observed in a series of hip or knee revisions. Aluminum can be identified in undecalcified bone matrix stained by solochrome azurine, a highly specific stain allowing the detection of 0.03 atomic %. Colocalization of aluminum and iron does not seem to be the fruit of chance but the cellular and molecular mechanisms are still poorly understood. Histochemistry is superior to spectroscopic analyses (EDS and WDS in scanning electron microscopy).

Predictive factors of scapular notching in patients with reverse shoulder arthroplasty.

INTRODUCTION: The main complication of reverse shoulder arthroplasty is the development of notches in the scapular pillar, which occurs in 44% to 100% of cases. Furthermore the functional score has been shown to be poorer in patients with high-grade notches. Many options have been proposed to reduce this risk. The purpose of this study was to evaluate the predictive factors of the development of scapular notches. MATERIALS AND METHODS: We retrospectively evaluated 133 shoulders in 121 patients with reverse shoulder arthroplasty. We performed a radiographic assessment of the effect of positioning the glenoid component with inferior overhang of the glenosphere and the glenometaphyseal angle. All patients were reviewed after 2years follow-up, including a clinical assessment based on the Constant score and X-rays to assess the presence of notches. RESULTS: Nineteen complications were reported, and 14 required revision surgery. We excluded patients in whom prosthetic components were changed. The quality of the X-rays was not satisfactory enough to be analyzed in over 15 patients so they were excluded. One hundred five patients were reviewed. At 2years follow-up, 50.4% of shoulders presented with notches. The Constant score was 69.3 points (54-83) in shoulders without notches, and 66.4 points (38-82) in shoulders with notches. The average glenosphere overhang was 3.5mm (-1 - 8mm). Notches were present in 65.5% if it was less than 3mm and 39.6% if it was more than 2mm (P<0. 05). The average glenometaphyseal angle was 27.3° (4-59°), and notches developed in 72.2% if it was more than 28° and 26.5% if it was less than 28° (P<0.05). CONCLUSION: The position of the metaglene influences the development of notches. The risk decreases if the glenosphere overhangs the glenoid. The degree of adduction of the arm influences the development of notches and can be correlated with the patient's BMI. LEVEL OF EVIDENCE: Level IV retrospective study.

Is radiographic measurement of distal femoral torsion reliable?

BACKGROUND: Distal femur torsion (DFT) is a crucial parameter in knee replacement surgery. The reference standard for measuring DFT is posterior condylar angle (PCA) measurement using computed tomography (CT). The objective of this study was to assess the feasibility and reliability of a radiographic PCA measurement method. MATERIALS AND METHODS: We studied 125 osteoarthritic knees in 79 patients (42 women and 37 men) with a mean age of 71.6 ± 8.8 years (range 47 to 86 years); 32 knees were aligned, 85 in varus, and eight in valgus. DFT was measured on an antero-posterior (AP) radiograph of the knee in 90° of flexion (known as the seated AP view). The PCA was defined as the angle subtended by the tangent to the posterior condyles and the transepicondylar axis (anatomic PCA [aPCA]) or the line connecting the lateral epicondyle to the medial sulcus (surgical PCA [sPCA]). The PCA was conventionally recorded as positive in the event of external torsion and negative in the event of internal torsion. PCA measurements were performed three times by each of five observers to allow assessments of inter-observer and test-retest reliabilities. RESULTS: aPCA was consistently negative (mean, -6.1 ± 1.6°) (range, 0 to -10°); inter-observer and test-retest reliability were satisfactory (0.54

Reverse wedge osteotomy of the distal radius in Madelung's deformity.

Madelung's deformity results from a growth defect in the palmar and ulnar region of the distal radius. It presents as an excessively inclined radial joint surface, inducing "spontaneous progressive palmar subluxation of the wrist". The principle of reverse wedge osteotomy (RWO) consists in the reorientation of the radial joint surface by taking a circumferential bone wedge, the base of which is harvested from the excess of the radial and dorsal cortical bone of the distal radius, then turning it over and putting back this reverse wedge into the osteotomy so as to obtain closure on the excess and opening on the deficient cortical bone. RWO corrects the palmar subluxation of the carpus and improves distal radio-ulnar alignment. All five bilaterally operated patients were satisfied, esthetically and functionally. Its corrective power gives RWO a place apart among the surgical techniques currently available in Madelung's deformity.

Trabecular microarchitecture in established osteoporosis: relationship between vertebrae, distal radius and calcaneus by X-ray imaging texture analysis.

INTRODUCTION: Osteoporosis is an alteration of bone mass and microarchitecture leading to an increased risk of fractures. A radiograph is a 2D projection of the 3D bone network exposing a texture, that can be assessed by texture analysis. We compared the trabecular microarchitecture of the spine, radius and calcaneus in a series of osteoporotic cadavers. MATERIALS AND METHODS: Thirty-four cadavers (11 men, 23 women), mean age 85.2±2.1years, were radiographed from T4 to L5 to identify those with vertebral fractures (FV). Non-fractured vertebrae (NFV), radius and calcaneus were taken and analyzed by densitometry, radiography and texture analysis under run-length, skeletonization of the trabeculae, and fractal geometry. RESULTS: Six subjects (five women, one man) were selected, mean age 82.5±5.5years. Twelve calcanei and 10 radii were taken. Two radii were excluded. The texture of NFV was significantly correlated (P<0.01) with that of the radius for horizontal run-lengths. No relationship between the texture of NFV and calcaneus was found. DISCUSSION: In the horizontal direction (perpendicular to the stress lines), the microarchitecture of NFV and radius showed a disappearance of the transverse rods anchoring the plates. Due to its particular microarchitecture, the calcaneus is not representative of the vertebral status. CONCLUSION: Bone densitometry provides no information about microarchitecture. Texture analysis of X-ray images of the radius would be a minimally invasive tool, providing an early detection of microarchitectural alterations. LEVEL OF EVIDENCE: IV retrospective study.

Total ankle arthroplasty - total ankle arthroplasty in Western France: influence of volume on complications and clinical outcome.

INTRODUCTION: Total ankle arthroplasty (TAA) has become an alternative to ankle arthrodesis in the treatment of advanced osteoarthritis. "The difficulty of performing a total ankle replacement and the corresponding steep learning curve" has resulted in a proposal "to limit ankle replacement to centers that have performed at least ten total ankle replacements for at least 3 years". The aim of this study was to evaluate the influence of the frequency of TAA procedures on the complications and outcome of these arthroplasties. MATERIALS AND METHODS: This retrospective series included 183 cases who underwent surgery between 1997-2010 in eight centers: three high volume centers performed at least five TAA per year (100 cases) and six low volume centers performed less than five TAA per year (78 cases). RESULTS: The clinical assessment was performed in 133 cases that were reviewed after a mean 39 months ± 29 of follow-up. The preoperative AOFAS score was 33 ± 4 and 77 ± 15 at the final follow-up. The five-year survival rate was 86%. No significant difference was found between the groups for the AOFAS score or implant survival at the final follow-up. The high volume centers experienced more complications (45% versus 13%) but fewer implant failures (8% versus 13%) overall compared to the low volume centers. DISCUSSION: The outcome of TAA depends mainly upon the pertinence of the indication and the associated procedures that may be necessary. Rather than limiting TAA to high volume reference centers, we suggest that the assessment of each case within a predetermined area should be done in a network. This would determine the degree of specialization required for each TAA case and provide all patients with safe and equal access to this therapeutic option. LEVEL OF EVIDENCE: IV - Retrospective study.

Treatment of complex fractures of the distal radius: a prospective randomised comparison of external fixation 'versus' locked volar plating.

The traditional treatment of severely impacted fractures of the distal radius involves bridging external fixation and maintaining reduction by applying continuous traction. The recent technique using fixed-angle screws within volar plates is reported restore the radial length and the articular profile whilst avoiding joint distraction. It is also believed to produce better and quicker clinical results. To test these claims, we carried out a randomised controlled comparison of the efficiency of external fixation (EF) 'versus' open reduction and internal fixation (ORIF) in treating severely impacted fractures of the distal radius. A total of 39 patients were treated with EF, eventually associated with percutaneous pinning, whereas 36 underwent ORIF with a locked volar plate. There was no significant difference in the two groups with regard to changes in the ulnar variance. Articular reduction was poor in two patients in the EF group with residual step-offs exceeding 2mm; another patient of the EF group suffered a secondary loss of reduction, healing with a severe articular malunion (>2mm). By contrast, articular reduction was satisfactory in all the patients of the ORIF group. The clinical results on the Green and O'Brien rating were significantly better in the ORIF group than in the EF group (p<0.01 at 6 weeks, p<0.05 at 6 months). Nevertheless, open reduction and volar plating did not yield better subjective results than EF. However, although not statistically significant, patients treated by ORIF seemed to resume their usual activities quicker than those treated with EF, suggesting that this technique may be adapted to a greater extent in the case of active, young individuals.

Isolated interfragmentary compression for nonunion of humeral shaft fractures initially treated by nailing: A preliminary report of seven cases.

INTRODUCTION: Plating with bone grafting is considered the gold standard treatment for nonunion of humeral shaft fractures. However, this complex procedure involves multiple risks. The aim of this study is to evaluate an alternative treatment using isolated axial interfragmentary compression for the dynamisation of humeral shaft nonunion after retrograde locked nailing. MATERIALS AND METHODS: Between January 2000 and May 2009, 124 humeral shaft fractures were treated in our trauma department with retrograde locked nailing using the unreamed humeral nail (UHN(®), Synthes, Paoli, PA, USA). Nonunion occurred in seven patients (5.6%) - five females and two males, mean age 44 years (range: 17-73 years). The nonunion was treated by applying isolated secondary interfragmentary compression. Mean follow-up was 43 months (range: 8-74 months). The Rommens score and the disabilities of the arm, shoulder and hand (DASH) score were used to evaluate the global functioning of the upper limb. RESULTS: The compression procedure was successful in all seven cases. In each case, the union occurred without any complications in 3-5 months. The mean DASH score was 25/100 (range: 8.3-60.8/100). The Rommens score was judged excellent for five of the seven patients but two were rated moderate. One of these suffered from complex regional pain syndrome type II since the fracture, and another developed a stiff shoulder 6 months after trauma. CONCLUSION: Isolated secondary interfragmentary compression appears to be a simple and successful procedure in cases of humeral nonunion.

Two-stage reconstruction of post-traumatic segmental tibia bone loss with nailing.

INTRODUCTION: Treatment of lower extremity segmental bone loss is difficult. Masquelet et al. proposed a two-stage technique: first, debridement and filling of bone loss with an acrylic spacer; second, bone reconstruction by filling with cancellous bone in the space left free (following cement removal) inside the so-called self-induced periosteal membrane. In the originally described technique, the fracture site is stabilized by an external fixator, which remains in place throughout the bone healing process, i.e., often longer than 9 months with all the known disadvantages of this type of assembly. Following the principle of two-stage reconstruction, we modified the technique by reconstructing around an intramedullary-locking nail placed in the first stage. HYPOTHESIS: This technique prevents the mechanical complications related to external fixator use and provides faster resumption of weight-bearing. PATIENTS AND METHODS: Twelve patients were operated for segmental tibial bone loss greater than 6cm resulting from injury (four cases) or aseptic necrosis (one case) or septic necrosis (seven cases). All the patients were operated on in an emergency setting and the first stage was performed before the 2nd week. A free muscle flap (ten patients) or a pediculated fasciocutaneous flap (two patients) was necessary during this first step to cover the site and provide good conditions for secondary bone growth. The follow-up was 39.5 months (range, 12-94 months). RESULTS: Complete weight-bearing was resumed at a mean 4 months. After the second step, all the patients except one had apparently healed (complete weight-bearing with no pain). Five septic complications occurred after the second step, in one case leading to reconstruction failure. Four other patients had infectious complications successfully treated (as of the last follow-up) either by changing the nail in two cases or by prolonged antibiotic therapy in two other cases, with no graft loss. DISCUSSION: The use of the intramedullary nail facilitates the Masquelet technique by allowing the patient to resume weight-bearing more quickly and avoiding secondary fractures. However, the risk of sepsis remains high but can be controlled without compromising the final bone union in four cases out of five. LEVEL OF EVIDENCE: Level IV. Retrospective study.

[Femoral reconstruction with impacted macroporous calcium phosphate ceramic in revision hip arthroplasty]. / Reconstruction fémorale par céramique de phosphate de calcium macroporeuse impactée au cours des reprises d'arthroplastie de hanche.

PURPOSE OF THE STUDY: Management of bone stock loss remains one of the most challenging problems for revision hip surgery. The aim of this retrospective study was to report the preliminary results of peri-prosthetic femoral defect reconstruction with impacted granules of calcium phosphate ceramic. MATERIAL AND METHODS: Fourteen hips in 13 patients (3 men and 10 women) were evaluated. Age at surgery ranged from 30 to 79 years (mean 66.1 years). All revised devices had been cemented. Femoral revision was indicated for loosening in eleven hips (including six septic cases), femoral osteolysis (one hip), persistent pain (one hip), and recurrent dislocation (one hip). On the preoperative radiological evaluation, bone defects were assessed as SOFCOT grade II in seven case, and grade III in fourteen. None was rated grade IV. Once the loose prosthesis had been removed, bone graft or ceramic granules (14 cases) were firmly impacted in the femoral canal. The stem was standard and always cemented using modern cementing technique. RESULTS: At a mean follow-up of 34 +/- 15 months (range 14-76 months), eleven of fourteen hips were rated good or very good according to the Postel-Merle-d'Aubigné score. One diaphyseal femoral fracture occurred and later united. Two hips required re-revision (one aseptic femoral loosening, one septic recurrence). Direct bonding between synthetic graft and bone was observed on standard radiographs in eleven cases. Stem subsidence occurred in two cases and was limited (mean 4.5 mm). DISCUSSION: Femoral bone reconstruction using impacted calcium phosphate ceramic in revision hip arthroplasty provided encouraging results in the short to mid term. Femoral stock restoration was achieved in the great majority. No adverse effect related to the use of a synthetic graft was noted. Further long-term evaluation is required before wider application.

Surgical management of trapezius palsy.

BACKGROUND: Injury to the spinal accessory nerve in the posterior cervical triangle leads to paralysis of the trapezius muscle. The aim of this study was to determine the indications for nerve repair or reconstructive surgery according to the etiology, the duration of the preoperative delay, and specific patient characteristics. METHODS: Of twenty-seven patients with a trapezius palsy, twenty were treated with neurolysis or surgical repair (direct or with a graft) of the spinal accessory nerve and seven were treated with the Eden-Lange muscle transfer procedure. Lymph node biopsy was the main cause of the nerve injury. The nerve repairs were performed at an average of seven months after the injury, and the reconstructive procedures were done at an average of twenty-eight months. Nerve repair was performed for iatrogenic injuries of the spinal accessory nerve, within twenty months after the onset of symptoms, and in one patient with spontaneous palsy. Reconstructive surgery was performed for cases of trapezius palsy secondary to radical neck dissection, for spontaneous palsies, and after failure of nerve repair or neurolysis. The mean follow-up period was thirty-five months. The functional outcome was assessed clinically on the basis of active shoulder abduction, pain, strength of the trapezius on manual muscle-testing, and level of subjective patient satisfaction. RESULTS: The results were good or excellent in sixteen of the twenty patients treated with nerve repair and in four of the seven patients treated with the Eden-Lange procedure. Poor results were seen in older patients and in patients with a previous radical neck dissection. CONCLUSIONS: Good results can be expected from a repair of the spinal accessory nerve if it is performed within twenty months after the injury, as the nerve is basically a purely motor nerve and the distance from the injury to the motor end plates is short. Muscle transfer should be performed in patients with spontaneous trapezius palsy, when previous nerve surgery has failed, or when the time from the injury to treatment is over twenty months. Treatment is less likely to succeed when the patient is older than fifty years of age or the palsy was due to a radical neck dissection, penetrating injury, or spontaneous palsy.

A meta-analysis of patellar replacement in total knee arthroplasty.

From individual randomized studies it is unclear whether the patella should be replaced during total knee replacement. We did a meta-analysis to provide quantitative data to compare patellar resurfacing with nonresurfacing during total knee arthroplasty. Only randomized, controlled trials reported between January 1966 and August 2003 comparing patellar replacement with patella retention were included for a total of 12 studies. Two reviewers assessed trial quality and extracted data from papers. The outcomes identified were reoperations for patellar problems, anterior knee pain, knee scores, stair climbing, and patient satisfaction. The resurfaced patella performed better, and we found an increased relative risk (defined by the ratio of the risk of the event in the resurfaced group on the risk of the event in the nonresurfaced group) for reoperation, for significant anterior knee pain, and for significant pain during stair climbing when the patella was left unresurfaced. No differences were observed between the two groups for International Knee Society function score, Hospital for Special Surgery score, and for patient satisfaction. Despite these general findings, forming a definitive conclusion is difficult because many confounding factors, such as component design, surgeon experience, and technical aspects of the surgery, might influence the result in a patient.

Surgical management of trapezius palsy.

BACKGROUND: Injury to the spinal accessory nerve in the posterior cervical triangle leads to paralysis of the trapezius muscle. The aim of this study was to determine the indications for nerve repair or reconstructive surgery according to the etiology, the duration of the preoperative delay, and specific patient characteristics. METHODS: Of twenty-seven patients with a trapezius palsy, twenty were treated with neurolysis or surgical repair (direct or with a graft) of the spinal accessory nerve and seven were treated with the Eden-Lange muscle transfer procedure. Lymph node biopsy was the main cause of the nerve injury. The nerve repairs were performed at an average of seven months after the injury, and the reconstructive procedures were done at an average of twenty-eight months. Nerve repair was performed for iatrogenic injuries of the spinal accessory nerve, within twenty months after the onset of symptoms, and in one patient with spontaneous palsy. Reconstructive surgery was performed for cases of trapezius palsy secondary to radical neck dissection, for spontaneous palsies, and after failure of nerve repair or neurolysis. The mean follow-up period was thirty-five months. The functional outcome was assessed clinically on the basis of active shoulder abduction, pain, strength of the trapezius on manual muscle-testing, and level of subjective patient satisfaction. RESULTS: The results were good or excellent in sixteen of the twenty patients treated with nerve repair and in four of the seven patients treated with the Eden-Lange procedure. Poor results were seen in older patients and in patients with a previous radical neck dissection. CONCLUSIONS: Good results can be expected from a repair of the spinal accessory nerve if it is performed within twenty months after the injury, as the nerve is basically a purely motor nerve and the distance from the injury to the motor end plates is short. Muscle transfer should be performed in patients with spontaneous trapezius palsy, when previous nerve surgery has failed, or when the time from the injury to treatment is over twenty months. Treatment is less likely to succeed when the patient is older than fifty years of age or the palsy was due to a radical neck dissection, penetrating injury, or spontaneous palsy.

Hybrid alumina total hip arthroplasty using a press-fit metal-backed socket in patients younger than 55 years. A six- to 11-year evaluation.

Between 1990 and 1992, we implanted 71 hybrid alumina-on-alumina hip arthroplasties in 62 consecutive patients under the age of 55 years, with a mean age of 46 years at surgery. There were 56 primary and 15 secondary procedures. The prostheses involved a cemented titanium alloy stem, a 32 mm alumina head, and a press-fit metal-backed socket with an alumina insert. Three patients (four hips) died from unrelated causes. Four hips had revision surgery for either deep infection, unexplained persistent pain, fracture of the alumina head, or aseptic loosening of the socket. The nine-year survival rate was 93.7% with revision for any cause as the end-point and 98.4% with revision for aseptic loosening as the end-point. The outcome in the surviving patients (50 patients, 57 hips) with a minimum five-year follow-up (mean eight years) was excellent in 47 hips (82.5%), very good in eight (14%), good in one and fair in one. A thin, partial, lucent line, mainly in zone III was present in 38% of the sockets and one socket had a complete lucency less than 1 mm thick. One stem had isolated femoral osteolysis. There was no detectable component migration nor acetabular osteolysis. This hybrid arthroplasty gave satisfactory medium-term results in active patients. The press-fit metal-backed socket appeared to have reliable fixation in alumina-on-alumina hip arthroplasty. The excellent results using cemented fixation of the stem may be related to the low production of wear debris.

[Surgical treatment of a femoral agenesis: a case report]. / Traitement chirurgical d'une agénésie fémorale sévère chez l'adulte: à propos d'un cas.

We report a case of severe femoral agenesia in an adult and propose a new surgical approach facilitating prosthesis fitting. The procedure involves insertion of a total hip arthroplasty, arthrodesis of the knee and amputation of the foot. The final prosthesis fits on the crural area with weight bearing on the ischiatic region, the lesser pelvis, and the articulated knee. Outcome was satisfactory at one year in our patient. Other surgical alternatives are presented.

Prevention of wear and osteolysis: alumina-on-alumina bearing.

Alumina-on-alumina bearings in total hip replacement have been used for 30 years. Excellent tribologic properties and extra low debris generation could, in theory, provide an answer to osteolysis. A review of the authors' experience with alumina-on-alumina bearings showed that, except in a few bearings that had been loose for a long time, osteolysis was not a problem. Although the cemented titanium stem and the alumina-on-alumina couple were not a problem, fixation of the socket had to be improved. To improve the socket fixation system and to avoid the use of a cemented titanium stem that may have created problems in the long-term, a new design was introduced in 1997. The current authors present the preliminary results of the first 96 hips with cementless fully-coated hydroxyapatite titanium alloy stems and sockets, 32-mm alumina femoral head, and alumina liner, both held with a Morse taper. Ninety-six consecutive hips in 89 patients (57 males, 32 females) with a median age of 46 years (range, 14-72 years) were analyzed. One socket was revised at 4 months because of poor primary stability in a patient with a severe acetabular fracture. One patient experienced a traumatic fracture of the implanted femur 3 weeks after surgery. The mean followup was 16 months (range, 4-38 months). One patient died from rupture of an aneurysm. Ninety-three hips in 86 patients were assessed regarding the clinical and radiologic ratings. Two patients (two hips) were interviewed by telephone. The Merle d'Aubigné rating system was 18 in 65 hips (59 patients), 17 in 25 hips (25 patients), and 16 in three hips (three patients) mainly related to a previous disability including limp, sciatic palsy, or stiffness. Examination of 93 available radiographs revealed no ostelolysis, no radiolucent lines at the last examination, and no subsidence. The level of excellent results, even in this young population, and lack of osteolysis and wear are encouraging, even if the followup is too short to allow any conclusions to be made.