Effects of a cervical disc prosthesis on maintaining sagittal alignment of the functional spinal unit and overall sagittal balance of the cervical spine

The object of this study is to review the early clinical results and radiographic outcomes following insertion of the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN), together with its effect on maintaining sagittal alignment of the functional spinal unit (FSU) and overall sagittal balance of the cervical spine for the treatment of single-level or two-level symptomatic disc disease. Forty-seven patients with symptomatic single or two-level cervical disc disease who received the Bryan Cervical Artificial Disc were reviewed prospectively. A total of 55 Bryan disc were placed in 47 patients. A single-level procedure was performed in 39 patients and a two-level procedure in the other eight. Radiographic and clinical assessments were made preoperatively and at 1.5, 3, 6, 9, 12, and 18 and up to 33 months postoperatively. Mean follow-up duration was 24 months, ranging from 13 to 33 months. Periods were categorized as early follow up (1.5-3 months) and late follow up (6-33 months). The visual analogue scale (VAS), neck disability index(NDI), Odom's criteria were used to assess pain and clinical outcomes. Static and dynamic radiographs were measured by hand and computer to determine the range of motion (ROM), the angle of the functional segmental unit (FSU), and the overall cervical alignment (C2-7 Cobb angle). With all of these data, we evaluated the change of the preoperative lordosis (or kyphosis) of the FSU and Overall sagittal balance of the cervical spine during the follow-up period. There was a statistically significant improvement in the VAS score from 7.0 +/- 2.6 to 2.0 +/- 1.5 (paired-t test, P = 0.000), and in the NDI from 21.5 +/- 5.5 to 4.5 +/- 3.9 (paired-t test P = 0.000). All of the patients were satisfied with the surgical results by Odom's criteria. The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level. Only 36% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis following surgery. However, the overall sagittal alignment of the cervical spine was preserved in 86% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 13% of patients during the late follow-up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 33% of the patients postoperatively. Clinical results are encouraging, with significant improvement seen in the Bryan Cervical Artificial disc. The Bryan disc preserves motion of the FSU. Although the preoperative lordosis (or kyphosis) of the FSU could not always be maintained during the follow-up period, the overall sagittal balance of the cervical spine was usually preserved.

The DUROM cup humeral surface replacement in patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis often leads to severe destruction of the glenohumeral joint, including synovitis and inflammation-induced alterations of the rotator cuff. Cup arthroplasty, or surface replacement of the shoulder, was introduced in the 1980s. The aim of this study was to evaluate the midterm results of the DUROM cup surface replacement for patients with rheumatoid arthritis affecting the glenohumeral joint.

METHODS

From 1997 to 2000, forty-two DUROM cup hemiprostheses were implanted in a cohort of thirty-five patients (forty-two shoulders), who were evaluated preoperatively and again at three, twelve, and more than sixty months postoperatively. Six patients (seven shoulders) were lost to follow-up. Thirty-five shoulders in twenty-nine patients (twenty-one women and eight men with an average age of 61.4 years) could be evaluated prospectively after an average follow-up period of 73.1 months. Patients were evaluated clinically with the use of the Constant score, and a detailed radiographic analysis was performed to determine the presence of endoprosthetic loosening, glenohumeral subluxation, and glenoid bone loss.

RESULTS

The mean Constant score for the thirty-five shoulders increased from 20.8 points preoperatively to 64.3 points at a mean of 73.1 months postoperatively. There were three revisions: one to replace an implant that was too large, another to treat glenoid erosion, and a third due to loosening of the implant. No additional cases of loosening of the prosthesis or changes in cup position were observed radiographically. Over the five-year follow-up period, proximal migration of the cup increased in 63% of the shoulders, and the glenoid depth increased in 31%. With the numbers studied, no differences in clinical outcome were identified between patients with a massive rotator cuff tear and those with a smaller or no tear.

CONCLUSIONS

The midterm results of the cemented DUROM cup surface replacement for patients with advanced rheumatoid arthritis of the shoulder are very encouraging, even for patients with a massive tear of the rotator cuff. The advantage of this cup arthroplasty is the less complex bone-sparing surgery. In the event of failure of the implant, other reliable salvage options remain.

Effect of crosslinking, remelting, and aging on UHMWPE damage in a linear experimental wear model

The objective of this study was to establish the effect of postirradiation melting as a function of irradiation dose on the wear behavior and material characteristics of ultrahigh molecular weight polyethylene. Our hypothesis was that a low dose of irradiation followed by melting would have the same improved wear performance as is found with higher doses of irradiation, but without the disadvantages associated with reduced fracture toughness. The hypothesis was tested by measuring the wear performance (wear track area, incidence of pitting and delamination) in a linear doubly curved-on-flat cyclic test, material behavior (elastic modulus, fracture toughness), and aging response (density changes through the thickness) of the following materials: elevated crosslinked groups--radiated at 25, 65, and 120 kGy, melted, sterilized and aged; a melted group--melted, sterilized, and aged; and a control group--sterilized and aged. Our findings suggest that postirradiation melting, not the irradiation dose, dominates the material property changes and wear response. Melting ensured reduced modulus and therefore decreased contact stresses, superior wear performance, and good resistance to aging, even after low levels of irradiation (25 kGy). The low modulus of the 25 kGy elevated crosslinked group, coupled with increased fracture toughness compared to samples irradiated at higher doses and a resistance to aging not found in the melted group, support our hypothesis. A low dose of irradiation followed by heat treatment has the same beneficial effects in terms of improved wear performance, but without the disadvantages of reduced fracture toughness found with higher doses of irradiation.

Results of the prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of the ProDisc-L total disc replacement versus circumferential fusion for the treatment of 1-level degenerative disc disease

STUDY DESIGN

A prospective, randomized, multicenter, Food and Drug Administration-regulated Investigational Device Exemption clinical trial.

OBJECTIVE

To evaluate the safety and effectiveness of the ProDisc-L (Synthes Spine, West Chester, PA) lumbar total disc replacement compared to circumferential spinal fusion for the treatment of discogenic pain at 1 vertebral level between L3 and S1.

SUMMARY OF BACKGROUND DATA

As part of the Investigational Device Exemption clinical trial, favorable single center results of lumbar total disc replacement with the ProDisc-L have been reported previously.

METHODS

Two hundred eighty-six (286) patients were treated on protocol. Patients were evaluated before and after surgery, at 6 weeks, 3, 6, 12, 18, and 24 months. Evaluation at each visit included patient self-assessments, physical and neurologic examinations, and radiographic evaluation.

RESULTS

Safety of ProDisc-L implantation was demonstrated with 0% major complications. At 24 months, 91.8% of investigational and 84.5% of control patients reported improvement in the Oswestry Low Back Pain Disability Questionnaire (Oswestry Disability Index [ODI]) from preoperative levels, and 77.2% of investigational and 64.8% of control patients met the > or =15% Oswestry Disability Index improvement criteria. Overall neurologic success in the investigational group was superior to the control group (91.2% investigational and 81.4% control; P = 0.0341). At 6 weeks and 3 months follow-up time points, the ProDisc-L patients recorded SF-36 Health Survey scores significantly higher than the control group (P = 0.018, P = 0.0036, respectively). The visual analog scale pain assessment showed statistically significant improvement from preoperative levels regardless of treatment (P < 0.0001). Visual analog scale patient satisfaction at 24 months showed a statistically significant difference favoring investigational patients over the control group (P = 0.015). Radiographic range of motion was maintained within a normal functional range in 93.7% of investigational patients and averaged 7.7 degrees.

CONCLUSIONS

ProDisc-L has been found to be safe and efficacious. In properly chosen patients, ProDisc-L has been shown to be superior to circumferential fusion by multiple clinical criteria.

[Pain and functional ability in patients with total disc replacement in the lumbar spine]

BACKGROUND

Total disc replacement in the lumbar spine is offered to patients with long-lasting localized low back pain secondary to degenerative disc disease, where non-operative treatment has failed. The aim of the study was to evaluate the outcome in patients offered operation with disc replacement using Prodisc II.

MATERIAL AND METHODS

All patients that had gone through disc replacement with Prodisc II at Kysthospitalet in Hagevik during the autumn of 2003 (n = 14) were included in a time-series designed study, with repeated measures 3 times preoperative and 5 times postoperative. The last measurement was done 2 years after the operation. Questionnaires and physical performance tests were used to measure differences in function, pain, psychological factors, fear of physical activity and dynamic flexibility of the back.

RESULTS AND INTERPRETATION

Preoperative measures showed reduction in pain, depression and somatisation. The other variables were rather stable before the operation. All the variables showed significant improvement 6 months after operation. While pain and perceived functional ability improved substantially after 3 months, physical performance did not show clinically important changes until 6 months after operation. The Oswestry Disability Index (ODI) showed a 29-point mean decrease after 2 years. 11 patients demonstrated a clinically significant improvement (ODI < or =10 points) after 2 years. The effect of this operative treatment should be assessed in randomised controlled trials with a longer follow-up.

[The HINTEGRA ankle: short- and mid-term results]

The HINTEGRA ankle was developed as an attempt to specifically address the needs of minimal bone resection, extended bone support, proper ligament balancing, and minimal contact stresses within and around the prosthesis. The purpose of this article was to present the design and rationale of this prosthesis, and to analyze the clinical and radiological short- to mid-term results particularly with respect to the revisions and learning curve. Of the 278 total ankle replacements (between 2000 and 2004) with the HINTEGRA ankle, 271 ankles [patients: 261, males: 133, females: 128, age: 58.4 years (range: 25-90 years)] were clinically and radiographically assessed after 36.1 months (range: 12-64 months). The preoperative diagnosis was post-traumatic osteoarthrosis in 206 cases (76.0%), systemic arthritis in 34 cases (12.5%), and a primary osteoarthrosis in 31 cases (11.5%). Beside 4 perioperative and 19 early postoperative complications, a late complication occurred in 40 cases (14.8%). Of these, 22 complications (8.2%) were not related to implants, and 18 complications (6.6%) were related to implants. In all, 39 cases (14.4%) were revised; of these, 5 cases (1.8%) were revised to ankle arthrodesis. All other 34 revision arthroplasties were successful and did not evidence any differences in the outcome to the non-revised ankles. The AOFAS hindfoot score improved from 40.3 (range: 14-61) to 85.0 (range: 44-100) points at last follow-up. Radiographically, the tibial component was stable in all remaining 266 ankles, and no tilting of the component occurred since surgery. The talar component was positioned too posteriorly in 12 ankles (4.4%). The concept of minimal bone resection and wide bony support was shown to be successful on the tibial and talar sides. Most complications occurred in the early cases of this series, and the learning curve was found to be short and steep. Despite the high amount of post-traumatic cases with limited soft tissue quality, the obtained function, pain relief, and patient satisfaction were promising and, compared with other devices, the results mostly were superior. This may support the belief that anatomically shaped surfaces, as is the case in the HINTEGRA ankle, may advance success in total ankle replacement.

[Anatomical and biomechanical aspects of total ankle replacement]

The success of total ankle replacement highly depends on how successfully the physiological kinematics are maintained or reconstructed. Normal kinematics of the ankle joint can be replicated by designing an implant that is as close as possible to the normal bony anatomy, aligning the ankle and balancing the ligaments. Mimicking normal kinematics and kinetics of a healthy ankle joint will consequently decrease damaging joint contact stress forces and stress forces on the surrounding soft tissue, which may cause wear, implant failure, and pain. This article summarizes the anatomical and biomechanical basics that are required in total ankle replacement.

[Ankle arthrodesis versus ankle replacement: a comparison]

Ankle arthrodesis is performed for the treatment of unstable, arthritic, painful, and deformed ankle joints. A wide variety of surgical options and approaches exist to treat the difficult problem of an ankle arthrodesis. In patients with only minor ankle deformity and minor bone loss arthroscopically assisted fusion is the treatment of choice. The risk for the development of a pseudarthrosis depends on clinical factors like corticoid medication, nicotine, incorrect alignment and improper mobilization. With adequate shoes the patients can remain asymptomatic for long time. Adjacent joints may show radiological degenerative changes in the long-term follow-up; however, they do not need to be clinically symptomatic. Nowadays total ankle replacement is a valid alternative. The surgical technique is demanding. Implants of the 1st and 2nd generation did not show satisfying results. The newer 3rd generation total ankle arthroplasties show promising medium-term and long-term results.

Bone remodeling, particle disease and individual susceptibility to periprosthetic osteolysis

Bone remodeling is a tightly coupled process consisting of repetitive cycles of bone resorption and formation. Both processes are governed by mechanical signals, which operate in conjunction with local and systemic factors in a discrete anatomic structure designated a basic multicellular unit (BMU). The microenvironment around total joint arthroplasty is a dynamic and complex milieu influenced by the chemical and physical stimuli associated with servicing the prosthesis. A key factor limiting the longevity of the prosthesis is polyethylene wear, which induces particle disease, and this may lead to increased and prolonged activity of BMUs resulting in periprosthetic osteolysis. Several pathways regulating BMU function have been reported in the past, including RANKL/RANK/OPG/TRAF6, TNF-alpha/TNFR/TRAF1, and IL-6/CD126/JAK/STAT. Moreover, the expression and functional activity of all these molecules can be affected by variations in their genes. These may explain the differences in severity of bone defects or prosthetic failure between patients with similar wear rates and the same prosthesis. Simultaneously, this data strongly support the theory of individual susceptibility to prosthetic failure.

Survivorship of the KUDO total elbow prosthesis--comparative study of cemented and uncemented ulnar components: 89 cases followed for an average of 6 years

BACKGROUND

The Kudo total elbow prosthesis (TEP) is a well-established implant with good mid-term results. The ulnar component can be placed with or without cement, and the humeral component is normally placed without cement.

METHODS

89 Kudo type-5 total elbow prostheses were evaluated after a mean follow-up of 6 (1.7-11) years. The indication for joint replacement was rheumatoid arthritis in all cases. 49 prostheses were placed without cement. In 40 cases, the ulnar component was cemented and the humeral component was uncemented.

RESULTS

In the uncemented group, 7 revisions had taken place. 3 of these ulnar components were shortstemmed and 4 were long-stemmed. No revisions had been performed in the hybrid group. In the uncemented group another 7 patients showed progressive radiolucencies, while 3 patients in the hybrid group showed progressive radiolucencies.

INTERPRETATION

In this group of RA patients, the survivorship of the cemented ulnar component was better than that of the uncemented ulnar component.

Early results of the Acclaim elbow replacement

The Acclaim total elbow replacement is a modular system which allows implantation in both unlinked and linked modes. The results of the use of this implant in primary total elbow replacement in 36 patients, operated on between July 2000 and August 2002, are presented at a mean follow-up of 36 months (24 to 49). Only one patient did not have good relief of pain, but all had improved movement and function.

No implant showed clinical or radiological loosening, although one had a lucent area in three of seven humeral zones. The short-term results of the Acclaim total elbow replacement are encouraging. However, 11 patients (30.5%) suffered an intra-operative fracture of the humeral condyle. This did not affect the outcome, or the requirement for further surgery, except in one case where the fracture failed to unite. This problem has hopefully been addressed by redesigning the humeral resection guide. Other complications included three cases of ulnar neuropathy (8.3%) and one of deep infection (2.8%).

Comparison of the stability of various internal fixators used in the treatment of osteochondritis dissecans--a mechanical model

The purpose of this study was to determine what characteristics of fixation devices used in the treatment of osteochondritis dissecans (OCD) contribute to improved stability to resist shear loading. An OCD model was designed using rigid polyurethane foam. Each specimen consisted of two components, an osteochondral fragment and a corresponding defect. A total of 40 specimens were prepared and assigned to one of four groups: control (no extrinsic stabilizer); two 2-mm-diameter Kirschner wires (K-wires), 40 mm in length; one threaded washer and a 28-mm screw; and one threaded washer and a 38 mm screw. Each specimen was mounted onto an Iosipescu shear test fixture and subjected to shear loads at a pseudo-static displacement rate of 0.075 mm/s. All groups demonstrated some stability; controls were significantly less stable than all other groups. The group with the threaded washer and 38-mm screw demonstrated the greatest stability (p < 0.001), and no difference was noted between the K-wire and 28-mm screw groups. These results suggest that, in this OCD model, friction conferred some intrinsic stability to resist loads in shear. However, stability was improved with the use of long implants that compressed the fragments together.

Magnetic resonance imaging clarity of the Bryan, Prodisc-C, Prestige LP, and PCM cervical arthroplasty devices

STUDY DESIGN

Prospective, randomized, controlled and double-blinded study on imaging of artificial discs.

OBJECTIVE

The purpose of this study is to compare postoperative imaging characteristics of the 4 currently available cervical arthroplasty devices at the level of implantation and at adjacent levels.

SUMMARY OF BACKGROUND DATA

Cervical arthroplasty is being performed increasingly frequently for degenerative disc disease and, in most cases, with frank neural compression. Unlike lumbar arthroplasty, performed mainly for axial back pain, decompression of neural elements may need to be confirmed with postoperative imaging after cervical arthroplasty.

METHODS

Preoperative and postoperative magnetic resonance imaging scans of 20 patients who had undergone cervical arthroplasty were assessed for imaging quality. Five cases each of the Bryan (Medtronic Sofamor Danek, Memphis, TN), Prodisc-C (Synthes Spine, Paoli, PA), Prestige LP (Medtronic Sofamor Danek), and PCM devices (Cervitech, Rockaway, NJ) were analyzed. Six blinded spinal surgeons scored twice sagittal and axial T2-weighted images using the Jarvik 4-point scale. Statistical analysis was performed comparing quality before surgery and after disc implantation at the operated and adjacent levels and between implant types. RESULTS.: Moderate intraobserver and interobserver reliability was noted. Preoperative images of patients in all implant groups had high-quality images at operative and adjacent levels. The Bryan and Prestige LP devices allowed satisfactory visualization of the canal, exit foramina, cord, and adjacent levels after arthroplasty. Visualization was significantly impaired in all PCM and Prodisc-C cases at the operated level in both the spinal canal and neural foramina. At the adjacent levels, image quality was statistically poorer in the PCM and Prodisc-C than those of Prestige LP or Bryan. CONCLUSIONS.: Postoperative visualization of neural structures and adjacent levels after cervical arthroplasty is variable among current available devices. Devices containing nontitanium metals (cobalt-chrome-molybdenum alloys in the PCM and Prodisc-C) prevent accurate postoperative assessment with magnetic resonance imaging at the surgical and adjacent levels. Titanium devices, with or without polyethylene (Bryan disc or Prestige LP), allow for satisfactory monitoring of the adjacent and operated levels. This information is crucial for any surgeon who wishes to assess adequacy of neural decompression and where monitoring of adjacent levels is desired.

Radiologic assessment of reverse shoulder arthroplasty

The reverse shoulder prosthesis was approved for clinical use in the United States in March 2004. This new prosthesis reverses the normal ball-and-socket relationship of the shoulder joint. As a result of replacement of the glenoid component with a ball and of the humeral head with a socket, the center of rotation is moved distally and medially, allowing more control of shoulder motion by the deltoid muscle. This improved geometric configuration allows shoulder reconstruction in patients who have irreparable rotator cuff damage with secondary arthropathy, pain, and "pseudoparalysis" (ie, inability to lift the arm above the horizontal). Patients experience a significant improvement in range of motion and markedly decreased pain after undergoing reverse shoulder arthroplasty; however, the procedure is associated with a relatively high rate of complications, including dislocation, infection, loosening, malpositioning of the glenoid component or fixation screws, disassembly of the humeral component, periprosthetic fracture, and inferior glenoid impingement leading to scapular erosion. Therefore, it is important that the radiologist be familiar with the normal and abnormal imaging appearances of this new prosthesis.

Polyethylene wear and rim fracture in total disc arthroplasty

BACKGROUND CONTEXT

Polyethylene (PE) has been used in total disc replacements (TDRs) in Europe since the 1980s. However, the extent of surface damage of PE, including rim fracture and wear, after long-term implantation remains poorly understood.

PURPOSE

The purpose of this study was to evaluate the magnitude and rate of PE wear and surface damage in TDRs.

STUDY DESIGN

TDR components were retrieved from patients undergoing revision TDR surgery and conversion to fusion.

PATIENT SAMPLE

Twenty-one implants (SB Charité III; DePuy Spine, Raynham, MA) were analyzed from 18 patients (12 female, 6 male) undergoing TDR revision surgery. The components were implanted between 1.8 and 16.0 years (average: 7.8 years) at L2-L3 (n=1), L3-L4 (n=1), L4-L5 (n=11), and L5-S1 (n=8). They were removed due to pain (in all cases) and were associated with subsidence (n=6), anterior migration (n=2), core dislocation (n=2), lateral subluxation (n=1), wear with wire marker fracture (n=1), end plate loosening (n=2), and osteolysis (n=1).

OUTCOME MEASURES

Clinical information was collected from medical records and radiographs. Retrieval analysis included dimensional measurements and assessment of the extent and severity of PE surface damage mechanisms.

METHODS

MicroCT scanning was used to identify the presence of internal cracks in the PE core and to scan the geometry of the retrievals. Light microscopy, coupled with white light interferometry, was used to evaluate the surface damage mechanisms at the dome and rim.

RESULTS

The dominant wear mechanism was adhesive/abrasive wear at both the dome and rim. End plate penetration (dome wear) ranged from 0.1 to 0.9 mm (average: 0.3 mm), and was correlated with implantation time (Spearman's rho=0.48, p=.03). There was also evidence of macroscopic rim damage, including radial and transverse cracking, fracture, plastic deformation, and third-body damage. End plate penetration measured at the rims ranged from 0.02 to 0.8 mm (average: 0.3 mm). Cracks in the core were oriented transversely in 11 of 21 implants (52%), and radially around the rim in 11 of 21 implants (52%). Radiographic wire marker fracture, observed in 9 of 21 implants (43%), was always associated with deformation, cracking, or fracture of the PE rim. In two cases, a fractured wire marker became lodged in the articulating surface between the PE and the metallic end plate.

CONCLUSIONS

This is the first study to quantitatively analyze the long-term PE damage mechanisms in contemporary TDRs. The TDRs displayed surface damage observed previously in both hip and knee replacements. Because of the evidence of increasing wear with implantation time, along with the demonstrated potential for osteolysis in the spine, regular long-term follow-up for patients undergoing TDRs is warranted.

Biomechanical evaluation of the Total Facet Arthroplasty System: 3-dimensional kinematics

STUDY DESIGN

An in vitro biomechanical study to quantify 3-dimensional kinematics of the lumbar spine following facet arthroplasty.

OBJECTIVES

To compare the multidirectional flexibility properties and helical axis of motion of the Total Facet Arthroplasty System (TFAS) (Archus Orthopedics, Redmond, WA) to the intact condition and to posterior pedicle screw fixation.

SUMMARY OF BACKGROUND DATA

Facet arthroplasty in the lumbar spine is a new concept in the field of spinal surgery. The kinematic behavior of any complete facet arthroplasty device in the lumbar spine has not been reported previously.

METHODS

Flexibility tests were conducted on 13 cadaveric specimens in an intact and injury model, and after stabilization with the TFAS and posterior pedicle screw fixation at the L4-L5 level. A pure moment of +/-10 Nm with a compressive follower preload of 600 N was applied to the specimen in flexion-extension, axial rotation, and lateral bending. Range of motion (ROM), neutral zone, and helical axis of motion were calculated for the L4-L5 segment.

RESULTS

ROM with the TFAS was 81% of intact in flexion (P = 0.035), 68% in extension (P = 0.079), 88% in lateral bending (P = 0.042), and 128% in axial rotation (P = 0.013). The only significant change in neutral zone with TFAS compared to the intact was an increase in axial rotation (P = 0.011). The only significant difference in helical axis of motion location or orientation between the TFAS and intact condition was an anterior shift of the helical axis of motion in axial rotation (P = 0.013).

CONCLUSIONS

The TFAS allowed considerable motion in all directions tested, with ROM being less than the intact in flexion and lateral bending, and greater than the intact in axial rotation. The helical axis of motion with the TFAS was not different from intact in flexion-extension and lateral bending, but it was shifted anteriorly in axial rotation. The kinematics of the TFAS were more similar to the intact spine than were the kinematics of the posterior fixation when applied to a destabilized lumbar spine.

[Complex proximal humerus fractures--management with a humeral head prosthesis? Clinical and radiological results of a prospective study]

BACKGROUND

Proximal humerus fractures are one of the most common fractures in elderly patients. In the treatment of complex proximal humerus fractures, primary hemiarthroplasty is still discussed controversially. The present study was undertaken to evaluate the results of primary hemiarthroplasty in the treatment of proximal humerus fractures with a modular prosthesis (EPOCA, Fa. Argomedical, Gifhorn, Germany).

MATERIAL AND METHODS

A prospective study of 24 patients with complex humerus fracture (NEER: IV/4, V/4, VI/4, and head split fracture) was performed from August 2000 to December 2002. Mean age was 75.6 years (range: 52-92); 18 patients were seen for follow-up after 0.5 and 1 year, respectively. The Constant-Murley score (max. 100 points) and the UCLA Rating System (max. 35 points) were calculated for functional assessment of the operated shoulder.

RESULTS

Fifteen patients (83%) were pain free 1 year after the operation. The Constant-Murley score improved from 52 (+/-17) to 56 (+/-18) at the second follow-up after 1 year. On the contralateral side a score of 86 (+/-10) was assessed (p<0.05 vs operated side). Correspondingly, shoulder function according to the UCLA Rating System improved [25 (+/-4); 27 (+/-5)].

CONCLUSIONS

Osteoporotic bone of older patients often may not permit stable internal fixation of complex proximal humerus fractures. In these situations primary hemiarthroplasty is the treatment of choice.