Sjoerd K. Bulstra

Osteogenic activity of OP-1 bone morphogenetic protein (BMP-7) in a human fibular defect

We performed a prospective, randomised double-blind study in 24 patients undergoing high tibial osteotomy to evaluate the effectiveness of human recombinant osteogenic protein (OP-1) on a collagen type-I carrier in a critically-sized fibular defect. The study had two phases, each evaluated by clinical, radiological and DEXA methods during the first postoperative year. The first concerned the validation of the model of the fibular defect, using positive (demineralised bone) and negative (untreated) controls. The second phase concerned the osteogenic potential of OP-1 on collagen type-I v collagen type-I alone. The results of the first phase established the critically-sized nature of the defect. In the untreated group no bony changes were observed while, in the demineralised bone group, formation of new bone was visible from six weeks onwards. The results of the second phase showed no significant formation of new bone in the presence of collagen alone, while in the OP-1 group, all patients except one showed formation of new bone from six weeks onwards. This proved the osteogenic activity of OP-1 in a validated critically-sized human defect.

Perichondral grafting for cartilage lesions of the knee.

Twenty-five patients with 30 chondral lesions of the knee were treated with an autogenous strip of costal perichondrium. The graft was fixed to the subchondral bone with Tissucol (Immuno, Vienna), a human fibrin glue. The leg was then immobilised for two weeks followed by two weeks of continuous passive motion. Weight-bearing was permitted after three months. The mean knee score (Ranawat, Insall and Shine 1976) changed from 73 before operation to 90 one year after; in 14 patients evaluated after two years there was no decrease. In 28 cases the defect was completely filled with tissue resembling articular cartilage. We conclude that in most cases perichondral arthroplasty of cartilage defects of the knee gives excellent results.

Long-term results of rib perichondrial grafts for repair of cartilage defects in the human knee

Summary. Eighty-eight patients with articular cartilage defects in the knee were treated by perichondrial arthroplasty between 1986 and 1992. An autogenous strip of costal perichondrium was fixed in place with fibrin glue, followed by immobilisation, continuous passive motion, and partial weightbearing. The results were evaluated using the Hospital for Special Surgery Score for knee function, radiographs, arthroscopy and the patient’s subjective opinion. The results after a mean follow-up of 52 months were good in 38%, fair in 8% and poor in 55%. Previous drilling or shaving of a defect, concomitant osteoarthritis, older age and a long history of complaints proved to be contraindications. Good results were seen in 91% of isolated defects. Perichondrial arthroplasty can be beneficial in the repair of cartilage defects. It will reduce symptoms in carefully selected cases, and avoid more extensive operations for osteoarthritis.Résumé. Depuis septembre 1986 jusqu’à decembre 1992 quatre-vingt huit patients presentant les lésions cartilagineuses au genou ont été traité par arthroplastie périchondrale. Dans les lésions, une partie du périchondre de la côte a été fixé avec de la colle de fibrine. Les soins consécutifs consistaient à une immobilisation, une mobilisation passive, et a une mise en charge partielle puis complète. L’évaluation des résultats a été fait avec l’aide de la cotation Hospital for Special Surgery pour l’articulations du genou, par examen radiologique, arthroscopie postoperatoire et recueil de l’opinion subjective du patient. Les résultats après une étude moyenne de cinquante deux mois ont été bon à 38%, modéréà 8% et mauvais à 55%. Les contre-indications pour cette technique sont des forages ou nettoyages précédents, l’arthrose, l’âge avancé du patient, et des douleurs préexistantes. Des bons résultats sont vus dans les lésions isolées à 91% (30/33). Nous concluons que l’arthroplastie avec périchondre peut être favorable pour réparer des lésions cartilagineuses. Cette technique peut diminuer les douleurs des patients bien sélectionnés et prévenir les opérations plus compliquées pour arthrose.

The role of small-colony variants in failure to diagnose and treat biofilm infections in orthopedics

Biomaterial-related infection of joint replacements is the second most common cause of implant failure, with serious consequences. Chronically infected replacements cannot be treated without removal of the implant, as the biofilm mode of growth protects the bacteria against antibiotics. This review discusses biofilm formation on joint replacements and the important clinical phenomenon of small-colony variants (SCVs). These slow-growing phenotypic variants often remain undetected or are misdiagnosed using hospital microbiological analyses due to their unusual morphological appearance and biochemical reactions. In addition, SCVs make the infection difficult to eradicate. They often lead to recurrence since they respond poorly to standard antibiotic treatment and can sometimes survive intracellularly.

Reliability and validity of the short questionnaire to assess health-enhancing physical activity (SQUASH) in patients after total hip arthroplasty

BackgroundDespite recognized benefits of regular physical activity on musculoskeletal fitness as well as general health, little is known about the physical activity behavior of patients after Total Hip Arthroplasty (THA). So far, no physical activity questionnaire has been validated in this category of patients. As the Short Questionnaire to Assess Health-enhancing physical activity (SQUASH) has been shown to be a fairly reliable and valid tool to gauge the physical activity behavior of the general Dutch adult population, we measured the reliability and relative validity of this tool in patients after THA.Methods44 patients (17 men and 27 women, mean age 71 ± 8 years) completed the SQUASH twice with an in-between period of 2 to 6 weeks (mean 3.7). Reliability was determined by calculating the Spearman correlation coefficient between the activity scores of the separate questions as well as the total activity scores from both administrations. Additionally, a Bland & Altman analysis was performed for the total activity scores. Relative validity was determined using the Actigraph™ accelerometer, worn by 39 patients (15 men and 24 women, mean age 70 ± 8 years) for a 2-week period following the second questionnaire, as a criterion measure.ResultsSpearmans correlation coefficient for overall reliability was 0.57. It varied between 0.45 and 0.90 for the separate questions. No systematic biases between readings were found. The Spearman correlation between Actigraph™ readings and total activity score was 0.67. It was 0.56 for total minutes of activity, 0.20 for time spent in light intensity activity, 0.40 for moderate activity and 0.35 for vigorous activity. Systematic bias was found between the SQUASH and the Actigraph™.ConclusionThe SQUASH can be considered to be a fairly reliable tool to assess the physical activity behavior of patients after THA. Validity was found to be comparable with those of other questionnaires, and as it is short and easy to fill in, it may prove to be a useful tool to assess physical activity in this particular subset of the population. However, the considerable systematic bias found in this study illustrates the need for further analysis of the validity of the SQUASH.

Minimally invasive and computer-navigated total hip arthroplasty: a qualitative and systematic review of the literature

BackgroundBoth minimally invasive surgery (MIS) and computer-assisted surgery (CAS) for total hip arthroplasty (THA) have gained popularity in recent years. We conducted a qualitative and systematic review to assess the effectiveness of MIS, CAS and computer-assisted MIS for THA.MethodsAn extensive computerised literature search of PubMed, Medline, Embase and OVIDSP was conducted. Both randomised clinical trials and controlled clinical trials on the effectiveness of MIS, CAS and computer-assisted MIS for THA were included. Methodological quality was independently assessed by two reviewers. Effect estimates were calculated and a best-evidence synthesis was performed.ResultsFour high-quality and 14 medium-quality studies with MIS THA as study contrast, and three high-quality and four medium-quality studies with CAS THA as study contrast were included. No studies with computer-assisted MIS for THA as study contrast were identified. Strong evidence was found for a decrease in operative time and intraoperative blood loss for MIS THA, with no difference in complication rates and risk for acetabular outliers. Strong evidence exists that there is no difference in physical functioning, measured either by questionnaires or by gait analysis. Moderate evidence was found for a shorter length of hospital stay after MIS THA. Conflicting evidence was found for a positive effect of MIS THA on pain in the early postoperative period, but that effect diminished after three months postoperatively. Strong evidence was found for an increase in operative time for CAS THA, and limited evidence was found for a decrease in intraoperative blood loss. Furthermore, strong evidence was found for no difference in complication rates, as well as for a significantly lower risk for acetabular outliers.ConclusionsThe results indicate that MIS THA is a safe surgical procedure, without increases in operative time, blood loss, operative complication rates and component malposition rates. However, the beneficial effect of MIS THA on functional recovery has to be proven. The results also indicate that CAS THA, though resulting in an increase in operative time, may have a positive effect on operative blood loss and operative complication rates. More importantly, the use of CAS results in better positioning of acetabular component of the prosthesis.

High incidence of complications and poor clinical outcome in the operative treatment of periprosthetic femoral fractures: An analysis of 71 cases.

BACKGROUND The purpose of this observational study was to determine the clinical results of the operative treatment of periprosthetic femoral fractures over a long period of time. METHODS The medical records of patients treated between 1993 and 2006 for a periprosthetic femoral fracture were obtained after a survey in two major hospitals. Radiographic evaluation was performed according to the Vancouver classification. All patients were contacted to fill out the Oxford hip score. RESULTS A total of 80 PPFs were identified in 79 patients. For 71 patients with 71 fractures, medical records and radiographs were available. The mean age at the time of fracture was 73.4 years (range: 38-95 years). The mean interval between initial arthroplasty and the time of fracture was 6.3 years. As many as 44 fractures occurred in patients with primary hip arthroplasty (62%) and 27 fractures in patients with revision implants (38%). All but two patients were treated operatively and 34 patients (48%) suffered from a complication, leading to a re-operation in 22 cases (33%). The most frequent indication for re-operation was re-fracture or implant failure. Vancouver type-C fractures lead to re-operations in 52% of the cases (11 of 20). A total of 36 patients (51%) were able to complete an Oxford hip score after a mean period of 64.9 months (range: 16-157 months). The other patients were lost to follow-up (45% were deceased and 4% were mentally impaired). The mean Oxford hip score was 27.8 (range: 12-57) and was significantly higher in patients suffering from a complication (p=0.02) and in patients with a periprosthetic fracture (PPF) after revision surgery (p=0.02). CONCLUSION The treatment of periprosthetic femoral fractures has a high complication rate and a large number of re-operations occur. The long-term clinical results are compromised by the event of a complication. The clinical results of treated fractures after a primary arthroplasty were better than after multiple arthroplasty procedures. Particularly, Vancouver type-C fractures showed high complication rates. This high complication rate should be taken into account for future studies in PPFs.

The oxford heup score : The translation and validation of a questionnaire into Dutch to evaluate the results of total hip arthroplasty

Background The evaluation of a total hip prosthesis would be most complete if the opinion of the patient, surgeon and the radiographs are combined. Disease specific patient outcome questionnaires are scarce, especially in Dutch. Methods The disease-specific 12-item questionnaire on the perception of patients with total hip replacement was translated into Dutch. We also investigated the extra value of two specific hip items, “the need for walking aids” and “sexual problems because of the hip”, four general items on overall satisfaction and one question about patient classification. The 14 hip-specific items were each scored from 1 (least difficulties) to 5 (most difficulties). The Dutch translation, the “Oxford Heup Score” (OHS) was tested on psychometric quality in a multicenter prospective study. Results The psychometric results of the OHS proved to be adequate. In the first postoperative year the score was very sensitive to changes, whereas in the second year it did not change significantly. The two added hip-specific questions were both filled out positively by more than 50% of the patients and thus fit perfectly into a hip-specific patient outcome questionnaire such as the OHS. Interpretation The OHS proves to be an appropriate instrument for assessment of the outcome of total hip replacement from the patients perspective. Together with the judgement of the surgeon, it provides useful insights into the question of whether this operation has been a success or not.

The effect in vitro of irrigating solutions on intact rat articular cartilage.

Rat patellae were preincubated with culture medium M199 for one hour and then with either fresh culture medium or Ringers solution, Ringer lactate, Ringer glucose, normal saline or Betadine for another hour. The rate of proteoglycan synthesis in the articular cartilage was then measured by uptake of 35SO4 for the next 16 hours. Cartilage metabolism was inhibited by all of the solutions even after a recovery time of 16 hours. The inhibition was by 5% for Ringers solution, 10% for Ringer glucose (p < 0.01), 20% for saline and Ringer lactate (p < 0.001) and 55% for Betadine (p < 0.001). Ringers solution is therefore the best choice for joint irrigation during arthroscopy or other procedures.

A Comparative Finite-Element Analysis of Bone Failure and Load Transfer of Osseointegrated Prostheses Fixations

An alternative solution to conventional stump–socket prosthetic limb attachment is offered by direct skeletal fixation. This study aimed to assess two percutaneous trans-femoral implants, the OPRA system (Integrum AB, Göteborg, Sweden), and the ISP Endo/Exo prosthesis (ESKA Implants AG, Lübeck, Germany) on bone failure and stem–bone interface mechanics both early post-operative (before bony ingrowth) and after full bone ingrowth. Moreover, mechanical consequences of implantation of those implants in terms of changed loading pattern within the bone and potential consequences on long-term bone remodeling were studied using finite-element models that represent the intact femur and implants fitted in amputated femora. Two experimentally measured loads from the normal walking cycle were applied. The analyses revealed that implantation of percutaneous prostheses had considerable effects on stress and strain energy density levels in bone. This was not only caused by the implant itself, but also by changed loading conditions in the amputated leg. The ISP design promoted slightly more physiological strain energy distribution (favoring long-term bone maintenance), but the OPRA design generated lower bone stresses (reducing bone fracture risk). The safety factor against mechanical failure of the two percutaneous designs was relatively low, which could be improved by design optimization of the implants.