Customised bi-compartmental knee arthroplasty shows encouraging 3-year results: findings of a prospective, multicenter study.

PURPOSE: The purpose of this study was to assess the clinical and patient-reported outcomes of a customised, individually made (CIM) bi-compartmental knee arthroplasty (BKA). METHODS: A prospectively recruited cohort of 79 patients was implanted with a CIM-BKA (patello-femoral plus either medial or lateral tibio-femoral, iDuo G2 system, Conformis, Billerica MA) at eight centres in the US and Germany. Patients were assessed for the 2011 KSS, KOOS, and ROM pre-operatively and at 2 weeks, 6 weeks, 12 weeks, 1 year, and 2 years post-operatively. RESULTS: The objective KSS score significantly improved from 69 at the pre-operative visit, to 94 at the 2-year post-operative time-point. Similar improvements were observed for the KSS function and satisfaction domains. Significant improvements from pre-operative levels were observed across all five domains of the KOOS. Two patients have undergone surgery to revise their CIM-BKA implant to total knees, resulting in a survivorship rate of 97.5% at an average follow-up of 2.6 years. CONCLUSIONS: CIM-BKA compares favourably to published scores as well as revision rates for previously available monolithic OTS-BKA implants. CIM-BKA implants provide surgeons with a viable and patient-specific monolithic implant solution as an option for patients presenting with bi-compartmental disease, who might, otherwise, be treated by performing uni-condylar + patello-femoral joint or bicruciate sparing TKA surgeries. Longer follow-up and higher numbers have to be awaited for further validation of these encouraging early results. LEVEL OF EVIDENCE: 3b (individual case-controlled study).

[Denervation of the patella: influence on mid-term results after total knee arthroplasty]. / Retropatellare Denervierung : Einfluss auf die mittelfristigen Ergebnisse von Knietotalendoprothesenimplantationen.

BACKGROUND: The purpose of the study was to determine possible differences in the mid-term results of total knee arthroplasty in patients treated with and without denervation of the patella. PATIENTS AND METHODS: This study included 80 total knee replacements in 71 patients who were treated with total knee replacement, either with (n = 40) or without (n = 40) simultaneous denervation of the patella out of a total population with 122 knee replacements in 100 patients. Comparability of both groups was achieved by applying matching criteria. All patients were reviewed by isokinetic tests, physical and radiological examination. The mean follow-up time was 2.2 years. RESULTS: The mean hospital for special surgery (HSS) score revealed no statistically significant differences between both groups (with denervation 77.9 ± 11.1 and without denervation 77.8 ± 11.0, p = 0.976). The isokinetic torque measurements with low angle velocity (60°/s) indicated slightly higher values during extension (60.2 ± 32.2 Nm versus 55.8 ± 25.2 Nm, p = 0.497) and flexion (52.4 ± 28.3 Nm versus 46.1 ± 22.3 Nm, p = 0.272) movements of the affected knee joint. However, the differences did not reach statistical significance. At high angle velocity (180°/s) no differences could be found between both groups. No cases of postoperative necrosis of the patella were observed. Anterior knee pain after denervation was reported in 6 cases (15 %) compared to 10 cases (25 %) in patients who were treated without denervation (p = 0.402). CONCLUSION: No statistically significant differences could be found between patients with and without denervation of the patella for total knee arthroplasty.

[Revision implants of the future: trends and new developments]. / Revisionsimplantate der Zukunft: Trends und neue Entwicklungen.

According to current prognostic studies the numbers of revision operations of hip and knee arthroplasty will increase worldwide. As many patients undergo several revisions and become older at the same time, orthopedic surgeons will have to cope with vast bony defects during operations. The introduction of highly porous metals as surface layer or metal augments has facilitated primary stabilization of prostheses. Short and mid-term results of these new products are promising. New developments in coatings, such as cationic antimicrobial peptides represent new alternatives for antibacterial therapy of periprosthetic infections and increase osteointegration of prosthesis components. Furthermore, the new revision systems have a modular design and can be individually adapted to the patient's bony conditions during operations. In most cases this can be done without cement or in a hybrid technique.

[Patient satisfaction and muscle torque after total knee replacement in dependence on body mass index]. / Patientenzufriedenheit und Muskelkraft nach Knietotalendoprothese in Abhängigkeit vom Body-Mass-Index.

AIM: In a monocentric study, we investigated patient satisfaction, clinical outcome and isokinetic muscle torque in dependence on the body mass index (BMI) in the mid-term outcome after total knee arthroplasty. PATIENTS AND METHODS: A group-matched study with two groups (each 40 knee arthroplasties in 40 patients) with a normal body mass index (BMI 20-25) and above 25 was conducted. The groups were matched for sex, diagnosis and age. Satisfaction, HSS score and isokinetic torque parameters with the Cybex 340 system were measured. RESULTS: There were no differences in the demographic data except for BMI. The HSS score was significantly lower in the overweight group (p = 0.04). Also there were more patients with an HSS score below 60 (bad result) in the group with the higher BMI (0 vs. 9, p = 0.002). Only one patient was not satisfied in the normal weight group, whereas 9 patients in the group BMI > 25 were not satisfied (p = 0.014). No differences between the groups could be found in maximum torque, work and power. CONCLUSION: The patient satisfaction was much lower in patients with BMI higher than 25. There were no differences between the groups in isokinetic torque parameters.

[The 2-year follow-up results of a patient-specific interpositional knee implant]. / Zwei-Jahres-Resultate mit einem patientenspezifischen metallischen Knieinterpositionsimplantat.

BACKGROUND: Besides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty. METHODS: From June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6 months (range 1-48 months) and the mean age of the patients was 54.5 years (range 39-65 years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out. RESULTS: The 2-4 year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%. CONCLUSION: Despite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2 year revision rate.

[Ankle arthroplasty: indications and current state]. / Sprunggelenkendoprothetik: Indikation und Stand.

Antecedent trauma is a major risk factor for the development of osteoarthritis of the ankle. Chronic inflammatory diseases, osteonecrosis and idiopathic arthritis are further important causes for ankle joint degeneration. Joint fusion represents the classic operative treatment of symptomatic ankle arthritis. The first attempts in total ankle replacement in the early 1970s led to high complication and revision rates. It was not until modern prosthesis designs respected the complex biomechanical conditions of the ankle joint that an alternative to joint fusion was available. Today a variety of models with specific advantages and disadvantages are available. Critical factors in ankle arthroplasty are proper patient selection and meticulous implantation.

[Operative treatment of the unicompartmental knee arthritis - results of a nationwide survey in 2008]. / Operative Therapie der unikompartimentellen Gonarthrose - Resultate einer bundesweiten Umfrage für das Jahr 2008.

BACKGROUND: Despite good long-term results of primary total knee arthroplasty, it is a commonly accepted aim to stave off joint replacement as long as possible, particularly in younger patients. In this situation the surgeon has to make a careful decision whether an arthroscopic procedure will be promising, a corrective osteotomy may be sensible or a joint replacement due to the patient's age is acceptable. High tibial osteotomy had become increasingly popular by use of the opened wedge technique combined with locking compression plates fixation in the past decades while it has been replaced step by step by total knee arthroplasty. In spite of this fact the German national agency of quality management (BQS) showed that the number of total knee replacements in Germany increased from 90 000 in 2003 to 146 000 in 2008. The share of unicompartmental knee replacements in this period doubled from 5.3 % to almost 10 %. The aim of the present study was to inquire current data regarding particular surgical treatment concepts of unicompartmental knee arthritis in Germany. MATERIAL AND METHODS: In a nationwide anonymous survey in May 2009 220 departments of orthopaedics and 230 departments of trauma surgery were asked about their treatment strategies in unicompartmental knee arthritis in middle-aged patients (30 to 60 years) with unilateral Outerbridge grade III-IV lesions. Overall 46 questions in 6 subject areas (structure of the department, number of treated patients, surgical methods, anaesthesiological procedures, perioperative management, postoperative treatment) were posed. With regard to the item "operative treatment" we asked for the importance of arthroscopic procedures, corrective osteotomies and different procedures of joint replacement. The interpretation was done with invariant data analysis by indication of numerical frequency and percentage distribution of selected options. RESULTS: Questionnaires were returned by 51.1 % of the surveyed departments. This represents a total number of 76,028 procedures in unicompartmental knee arthritis in middle-aged patients. First of all, arthroscopic procedures were applied (50.4 %), followed by knee replacements (43.4 %, of which 87.3 % were total knee replacements, 12.3 % unicompartmental knee replacements and 0.4 % tibial hemiarthroplasties) and corrective osteotomies (6.1 %). In 59.8 % of the 38,376 arthroscopic procedures a microfracturing and in 28.2 % an abrasion arthroplasty was done. Most of the corrective osteotomies were performed at the proximal tibia (90.9 %) using an open wedge technique (73 %) and internal fixation with locking compression plates (72 %). 75.2 % of the responders performed cemented unicompartmental arthroplasties (97.8 %) with an average number of 23.2 per year. 43.4 % believe that bicompartmental arthroplasty in case of additional affection of the femoropatellar joint is an option and 22.6 % believe in the expected advantages of patient-specific unicompartmental implants. Total knee arthroplasties are performed with an average of 197.4 per year, most frequently using the free-hand technique (85.5 %) and medial-parapatellar approach (82 %). Interpositional knee devices were only used in 9.1 % of responding departments with an average number of 6.6 per year. Only procedures with low difficulty level such as arthroscopies were done by residents in a higher number (16.9 %). Procedures with higher difficulty level were mainly done by consultants, senior or chief surgeons. CONCLUSION: In total, arthroscopic procedures still play an essential role in the treatment of unicompartmental knee arthritis prior to joint replacement. Total knee arthroplasty was preferred even though the number of unicompartmental knee replacements was only slightly increasing. Periarticular corrective osteotomies have gained in importance since the introduction of locking compression plates. Interpositional knee devices play a minor role in the treatment of unilateral knee arthritis in Germany.

Fixation of revision TKA: a review of the literature.

PURPOSE: Early aseptic loosening is a major complication in revision total knee arthroplasty (TKA). It is well accepted that intramedullary stems improve the anchoring of the prosthetic components; however, controversy still exists about the optimal fixation technique of the stems (cementless, hybrid, cemented). METHODS: A literature review was carried out in the main medical databases from 1980 to 04/2010 to evaluate the available literature by evidence-based criteria and to analyse the results of the single studies regarding fixation technique in knee revision arthroplasty. RESULTS: There are four studies regarding the cementless fixation. Eight studies reported the hybrid technique and five studies the cemented technique. Hybrid and cemented techniques are comparable regarding the survival of arthroplasties, the rate of aseptic loosening and the clinical outcome. However, most studies just show a low level of evidence (LoE III and IV), a small to medium number of cases and a short follow-up. CONCLUSION: Based on the current literature, no final statement can be drawn regarding the optimal fixation technique in revision TKA. Future RCTs are needed to enable conclusive statements about the possible advantages and disadvantages of the single fixation techniques, although the clinical implementation often is critical.

Cup positioning in THA: current status and pitfalls. A systematic evaluation of the literature.

The correct determination of cup orientation in THA regarding the intraoperative as well as the postoperative assessment due to the pelvic tilt and rotation with inexact incorporation of the pelvis is uncertain. The anterior pelvic plane (APP) seems to be the most reliable reference frame and computer-assisted navigation systems seem to provide the best tool for correct implantation to date. For the intraoperative assessment of the APP, the exact determination of the bony landmarks is mandatory. For the standard plain radiography, standardized positioning of the patient and approximation of pelvic tilt by a lateral view are mandatory. An additional CT must be carried out for certain indications. More emphasis has to be given to the individuality of pelvic tilt and range of motion.

[Current operative strategies for rotator cuff tears in German hospitals]. / Aktuelle operative Therapiestrategien der Rotatorenmanschettenruptur an deutschen Kliniken.

The surgical treatment of rotator cuff lesions is still a controversial subject. We therefore decided to perform a study designed to yield an overview of the treatment modalities currently applied in Germany. A nationwide questionnaire survey was sent to 470 orthopaedic and trauma departments to ask about their surgical treatment of rotator cuff lesions: frequency of operative treatment, methods used in diagnosis and types of operative treatment; particular attention was paid to the application of minimally invasive techniques and to postoperative rehabilitation. The response rate was 55%. In all, 30,462 arthroscopic treatments were recorded for the year 2004, 9,094 of which were open or mini-open techniques and 2,528 were endoscopic reconstructions of the rotator cuff. Overall, we found that arthroscopic rotator cuff repair was performed in only 111 of the 257 departments from which responses were received and that the majority of surgeons preferred to use sutured and nonresorbable anchors. The postoperative treatment varies widely, from the full range of motion allowed within the first postoperative week to substantially more restrictive regimens. We see that the arthroscopic repair is still not the standard treatment for rotator cuff lesions in Germany. Further research is clearly still needed especially in the area of postoperative treatment.

[Knowledge transfer and student's satisfaction in orthopaedics--a survey of 476 students]. / Wissensvermittlung und Studentenzufriedenheit in der Orthopädie--Eine Querschnittsuntersuchung an 476 Studenten.

AIM: The aim of the current study was to find out about the student's growth of knowledge and satisfaction in orthopaedics. We performed a survey among 476 students of one faculty. METHOD: We performed an anonymous survey in which the students had to answer a questionnaire which consisted of items according to knowledge in orthopaedics, subjective satisfaction and according to the difficulty of the asked questions. RESULTS: 74% of students disliked the so-called "hammerexam." 56% believe that the transfer of knowledge is good in lectures and bedside teaching courses. 20% prefer to cancel the "hammerexam," 30% would prefer to spend more time for important sections such as surgery and internal medicine and 20% would prefer it if the practical aspects of medicine were placed in the foreground. During the third and fourth semesters, the increase of knowledge is at its highest but is reduced later. 4% of all asked students are planning to become orthopaedic surgeons. CONCLUSION: Our study demonstrates that good knowledge transfer within the modified lectures and bedside teaching lessons is achieved. Student satisfaction is high. Only very few students are critical about their current situation.

[Risk factors associated with heterotopic ossifications in primary total hip arthroplasty]. / Risikofaktoren für heterotope Ossifikationen in der primären Hüftgelenkstotalendoprothetik.

AIM: The purpose of this study was to determine the important predisposing factors associated with heterotopic ossifications (HO) after total hip arthroplasty. METHOD: 589 patients were examined 6 months after primary total hip arthroplasty with regard to periarticular ossifications. Several predetermining factors were evaluated using the hospitalization records and preoperative X-ray examination. RESULTS: A significantly increased frequency of heterotopic ossifications was found for male gender, patients with very high body mass index (BMI), low preoperative range of motion (ROM), long duration of operation and large preexistent osteophytes (p < 0.05). Only one out of the one hundred patients with an BMI < 22.6 developed severe HO (Brooker III). Out of the one hundred patients with the best preoperative ROM (> or = 140 degrees ) only one case developed severe ossifications (Brooker III). There was no correlation with the use of acrylic bone cement or the patient's age. The frequency of HO was significantly reduced both as well by nonsteroidal antiinflammatory drugs as from postoperative radiation prophylaxis. CONCLUSION: In patients undergoing total hip arthroplasty with low preoperative ROM in the hip joint, large osteophytes and a very high BMI an efficient prophylaxis against HO is of great importance.

[Complex regional pain syndrome type I (CRPS I). Pathophysiology, diagnostics, and therapy]. / Das komplexe regionale Schmerzsyndrom Typ I (CRPS I). Ursachen, Diagnostik und Therapie.

Complex regional pain syndrome type I (CRPS type I)--formerly termed Sudeck's atrophy or reflex sympathetic dystrophy (RSD)--causes chronic, poorly controllable pain, autonomic, sensorimotor disorders,and serious trophic alterations in the later stages. It develops in the distal extremities mostly after minimal trauma or surgical intervention and rarely spontaneously. The severity of symptoms is disproportionate to the causative event. The latest scientific findings show that the previously called reflex sympathetic dystrophy (RSD), which was supposed to be a result of a hyperreactive autonomic nervous system,is a very complex syndrome that occurs on different integration levels of the nervous system. Sympathetically maintained pain (SMP) may be facultatively characteristic, but is not to be misunderstood as an underlying mechanism. A neurogenic inflammation reaction has recently been discussed, just as had been postulated by Paul Sudeck long before. That was the reason why the International Association for the Study of Pain (ISAP) introduced the more descriptive term "complex regional pain syndrome" (CRPS) type I in 1994. Due to the complexity of the process necessitating qualified knowledge, it is important to immediately refer patients to a specialized pain OPD or clinic. The diagnosis of CRPS type I is based upon a carefully taken case history and a clinical examination by an experienced practitioner. Imaging diagnostic tools and laboratory findings are of no or only low predicative value. The question of whether SMP exists after diagnosing CRPS type I is eminent for therapy planning. Therefore, diagnostic regional anesthetics are still important in spite of their uncertain prognostic relevance. Physical therapy, occupational therapy, medical treatment, and psychotherapy play an important role in the primary treatment of CRPS type I as noninvasive procedures. Despite heavy criticism, invasive sympathetic block, subsequent to adequate diagnostics, is an important part of the therapeutic concept. A multimodal therapeutic concept, which includes all available possibilities, is absolutely necessary to avoid grave permanent disabilities caused by insufficient or failed therapy. Nevertheless, already established as well as new treatment modalities have to be critically observed by further randomized, prospective control trials.