Positive outcomes following Autologous Matrix-Induced Chondrogenesis (AMIC) in the treatment of retropatellar chondral lesions: a retrospective analysis of a patient registry

BACKGROUND

The patellofemoral joint is a challenging environment for treating chondral defects. Among the surgical options for the treatment of chondral defects, the single-stage Autologous Matrix-Induced Chondrogenesis (AMIC) procedure uses a porcine collagen I/III membrane to enhance bone-marrow stimulation. However, longer term outcomes data are rare for this specific indication. In order to provide real-world information, an ongoing registry has been established to record patient data and outcomes when AMIC is used to treat chondral and osteochondral lesions.

METHODS

Patient data were retrieved from an ongoing, prospective, multisite registry of patients who had undergone AMIC treatment of chondral defects. We identified 64 patients who had undergone AMIC for patellofemoral chondral defects and for whom pre-operative and at least 1 post-operative score were available were included in this retrospective data analysis. Outcomes were assessed via the KOOS, VAS pain, and the Lysholm scores. Outcomes at the post-operative time-points were analysed using a factorial ANOVA with post-hoc testing while linear regression was used to assess associations between the change in the Lysholm score and lesion size.

RESULTS

There was a significant improvement in Lysholm, VAS pain, and KOOS scores from pre-operative to the 1st year post-operative (p < 0.001), and this was maintained during the follow-up.

CONCLUSIONS

The forces exerted on the patellofemoral joint make this a challenging scenario for chondral repair. Our data demonstrates that the AMIC procedure with a collagen I/III membrane is an effective treatment for retropatellar cartilage lesions, and provides reliable results, with decreased pain and improved function. Importantly, these improvements were maintained through the follow-up period.

Acute isolated injury of the posterior cruciate ligament treated by a dynamic anterior drawer brace: a preliminary report

We investigated the role of a functional brace worn for four months in the treatment of patients with an acute isolated tear of the posterior cruciate ligament to determine whether reduction of the posterior tibial translation during the healing period would give an improved final position of the tibia. The initial and follow-up stability was tested by Rolimeter arthrometry and radiography. The clinical outcome was evaluated using the Lysholm score, the Tegner score and the International Knee Documentation Committee scoring system at follow-up at one and two years. In all, 21 patients were studied, 21 of whom had completed one-year and 17 a two-year follow-up. The initial mean posterior sag (Rolimeter measurement) of 7.1 mm (5 to 10) was significantly reduced after 12 months to a mean of 2.3 mm (0 to 6, p < 0.001) and to a mean of 3.2 mm (2 to 7, p = 0.001) after 24 months. Radiological measurement gave similar results. The mean pre-injury Lysholm score was normal at 98 (95 to 100). At follow-up, a slight decrease in the mean values was observed to 94.0 (79 to 100, p = 0.001) at one year and 94.0 (88 to 100, p = 0.027, at two years). We concluded that the posterior cruciate ligament has an intrinsic healing capacity and, if the posteriorly translated tibia is reduced to a physiological position, it can heal with less attentuation. The applied treatment produces a good to excellent functional result.

Low reoperation rate with the Medoff sliding plate: 1 technical failure in 63 trochanteric hip fractures

The Medoff sliding plate was designed to treat unstable intertrochanteric and subtrochanteric fractures. This plate has a dual sliding capability along both the femoral shaft and neck in order to improve bone coaptation, interfragment compression and hence load-sharing between bone and implant in hip fractures. In a retrospective study of 63 patients (mean age 82 (51-98) years) with intertrochanteric (n 44) and high subtrochanteric fractures (n 19), we assessed the results with the Medoff sliding plate. All patients, except 1 lost to follow-up, were examined clinically and radiographically. 14 patients died within 1 year, and in the other, the mean follow-up was 15 (6-30) months. 1 technical failure occurred, leading to a single reoperation. The low technical failure rate suggests that the Medoff sliding plate with combined compression modus is suitable for treating intertrochanteric and high subtrochanteric fractures.

Repair of superficial osteochondral defects with an autologous scaffold-free cartilage construct in a caprine model: implantation method and short-term results

OBJECTIVE

To compare four different implantation modalities for the repair of superficial osteochondral defects in a caprine model using autologous, scaffold-free, engineered cartilage constructs, and to describe the short-term outcome of successfully implanted constructs.

METHODS

Scaffold-free, autologous cartilage constructs were implanted within superficial osteochondral defects created in the stifle joints of nine adult goats. The implants were distributed between four 6-mm-diameter superficial osteochondral defects created in the trochlea femoris and secured in the defect using a covering periosteal flap (PF) alone or in combination with adhesives (platelet-rich plasma (PRP) or fibrin), or using PRP alone. Eight weeks after implantation surgery, the animals were killed. The defect sites were excised and subjected to macroscopic and histopathologic analyses.

RESULTS

At 8 weeks, implants that had been held in place exclusively with a PF were well integrated both laterally and basally. The repair tissue manifested an architecture similar to that of hyaline articular cartilage. However, most of the implants that had been glued in place in the absence of a PF were lost during the initial 4-week phase of restricted joint movement. The use of human fibrin glue (FG) led to massive cell infiltration of the subchondral bone.

CONCLUSIONS

The implantation of autologous, scaffold-free, engineered cartilage constructs might best be performed beneath a PF without the use of tissue adhesives. Successfully implanted constructs showed hyaline-like characteristics in adult goats within 2 months. Long-term animal studies and pilot clinical trials are now needed to evaluate the efficacy of this treatment strategy.

Impact loading of articular cartilage during transplantation of osteochondral autograft

Surgical reconstruction of articular surfaces by transplantation of osteochondral autografts has shown considerable promise in the treatment of focal articular lesions. During mosaicplasty, each cylindrical osteochondral graft is centred over the recipient hole and delivered by impacting the articular surface. Impact loading of articular cartilage has been associated with structural damage, loss of the viability of chondrocytes and subsequent degeneration of the articular cartilage. We have examined the relationship between single-impact loading and chondrocyte death for the specific confined-compression boundary conditions of mosaicplasty and the effect of repetitive impact loading which occurs during implantation of the graft on the resulting viability of the chondrocytes.

Fresh bovine and porcine femoral condyles were used in this experiment. The percentage of chondrocyte death was found to vary logarithmically with single-impact energy and was predicted more strongly by the mean force of the impact rather than by the number of impacts required during placement of the graft. The significance of these results in regard to the surgical technique and design features of instruments for osteochondral transplantation is discussed.

[Closing wedge osteotomy of the tibial head in treatment of single compartment arthrosis]

Closing wedge high tibial osteotomy is an efficient method for the treatment of medial osteoarthritis of the knee. Prerequisites of successful surgery are proper indication and planning as well as the understanding of biomechanics and pathophysiology. The technique of osteotomy to choose (opening or closing wedge) depends on the type of malalignment and on additional pathologies. The surgical technique demands high precision to realize the planned correction and to avoid complications. Implants with angular stability provide advantages compared to traditional implants. Correct indication and surgical technique results in a desirable follow-up, which often lasts for at least 10 years. The effect on the prognosis of the young patient with cartilage damage is still unclear.

Short-term load bearing capacity of osteochondral autografts implanted by the mosaicplasty technique: an in vitro porcine model

Articular surface congruency and graft stability are considered essential factors in the success of osteochondral grafting; however, quantitative measures of short-term load bearing capacity of grafts implanted by the mosaicplasty technique have not been reported. The purpose of this study was to develop a live tissue in vitro model to examine short-term fixation strength of mosaicplasty autografts immediately after and 1 week following graft implantation. Cylindrical osteochondral autografts were implanted in vitro by the mosaicplasty technique on five pairs of porcine femoral condyles within one and a half hours of animal sacrifice. Immediately following the surgical procedure, graft push-in and pull-out strength tests as well as indentation tests to determine modulus of the surrounding cancellous bone were performed on half of the specimens from the distal femurs of each animal. The remaining specimens, matched for location in the contralateral leg, were incubated in culture medium for 7 days prior to performing the same set of mechanical tests. Averaged push-in and pull-out graft fixation strength decreased 44% from 135.7 to 75.5N over the 7-day period, while no change in modulus was detected in the surrounding cancellous bone. These in vitro results demonstrate a substantial deterioration of short-term fixation strength of mosaicplasty grafts from the immediate post-operative state. Such a reduction in short-term graft load bearing capacity may pose a threat to the surgically established articular surface congruency and blood vessels formed during the early stages of the healing response.

Ten-year patient and prosthesis survival after unipolar hip hemiarthroplasty in female patients over 70 years old

We found that 162 unipolar hemiarthroplastics of the hip were performed between 1989 and 1995 on women over 70 years of age in our institution. The mean age was 84 years (70 to 99). Cumulative survival of the prostheses was 98% at 1 year and 94% after 5 and 10 years. Of the original patients, 137 have died. Survival rate for patients was 73% at 1 year, 23% at 5 years, and 6% at 10 years. Eighteen patients could be accounted for, with a mean follow-up time of 7.7 years (5.5-11.3 years). The mean Harris hip score was 80 points (55-100). Protrusion was observed in 3 patients. The treatment of cervical neck fracture with unipolar hip prostheses is a valuable method, with a low complication rate, particularly in women over 70 years for whom life expectancy may be short.

Treatment of cartilage defects of the talus by autologous osteochondral grafts

We reviewed retrospectively 11 patients who had been treated surgically by open autologous osteochondral grafting for symptomatic chondral or osteochondral defects of the dome of the talus between 1996 and 1999. The mean ages of the eight men and three women were 34.2 and 25.9 years, respectively, with a mean time to follow-up of 24 months. The results of functional outcome were prospectively obtained using the MODEMS AAOS foot and ankle follow-up questionnaire, the AOFAS ankle-hindfoot scale and the Hannover scores for the ankle.

The grafts were harvested from the ipsilateral knee. Good to excellent results were obtained for the ankle without adverse effects on the knee. We believe that autologous osteochondral grafting should be considered for the patient with a symptomatic osteochondral defect of the talus.

Treatment of cartilage defects of the talus by autologous osteochondral grafts

We reviewed retrospectively 11 patients who had been treated surgically by open autologous osteochondral grafting for symptomatic chondral or osteochondral defects of the dome of the talus between 1996 and 1999. The mean ages of the eight men and three women were 34.2 and 25.9 years, respectively, with a mean time to follow-up of 24 months. The results of functional outcome were prospectively obtained using the MODEMS AAOS foot and ankle follow-up questionnaire, the AOFAS ankle-hindfoot scale and the Hannover scores for the ankle. The grafts were harvested from the ipsilateral knee. Good to excellent results were obtained for the ankle without adverse effects on the knee. We believe that autologous osteochondral grafting should be considered for the patient with a symptomatic osteochondral defect of the talus.

Articular cartilage repair using a tissue-engineered cartilage-like implant: an animal study

OBJECTIVE

Because articular cartilage has limited ability to repair itself, treatment of (osteo)chondral lesions remains a clinical challenge. We aimed to evaluate how well a tissue-engineered cartilage-like implant, derived from chondrocytes cultured in a novel patented, scaffold-free bioreactor system, would perform in minipig knees with chondral, superficial osteochondral, and full-thickness articular defects.

DESIGN

For in vitro implant preparation, we used full-thickness porcine articular cartilage and digested chondrocytes. Bioreactors were seeded with 20x10(6) cells and incubated for 3 weeks. Subsequent to culture, tissue cartilage-like implants were divided for assessment of viability, formaldehyde-fixed and processed by standard histological methods. Some samples were also prepared for electron microscopy (TEM). Proteoglycans and collagens were identified and quantified by SDS-PAGE gels. For in vivo studies in adult minipigs, medial parapatellar arthrotomy was performed unilaterally. Three types of defects were created mechanically in the patellar groove of the femoral condyle. Tissue-engineered cartilage-like implants were placed using press-fit fixation, without supplementary fixation devices. Control defects were not grafted. Animals could bear full weight with an unlimited range of motion. At 4 and 24 weeks postsurgery, explanted knees were assessed using the modified ICRS classification for cartilage repair.

RESULTS

After 3-4 weeks of bioreactor incubation, cultured chondrocytes developed a 700-microm- to 1-mm-thick cartilage-like tissue. Cell density was similar to that of fetal cartilage, and cells stained strongly for Alcian blue and safranin O. The percentage of viable cells remained nearly constant (approximately 90%). Collagen content was similar to that of articular cartilage, as shown by SDS-PAGE. At explantation, the gross morphological appearance of grafted defects appeared like normal cartilage, whereas controls showed irregular fibrous tissue covering the defect. Improved histologic appearance was maintained for 6 months postoperatively. Although defects were not always perfectly level upon implantation at explanation the implant level matched native cartilage levels with no tissue hypertrophy. Once in place, implants remodelled to tissues with decreased cell density and a columnar organization.

CONCLUSIONS

Repair of cartilage defects with a tissue-engineered implant yielded a consistent gross cartilage repair with a matrix predominantly composed of type II collagen up to 6 months after implantation. This initial result holds promise for the use of this unique bioreactor/tissue-engineered implant in humans.

In situ compressive stiffness, biochemical composition, and structural integrity of articular cartilage of the human knee joint

OBJECTIVE

Reduction of compressive stiffness of articular cartilage has been reported as one of the first signs of cartilage degeneration. For the measurement of in situ compressive stiffness, a hand-held indentation probe has recently been developed and baseline data for macroscopically normal knee joint cartilage were provided. However, the histological stage of degeneration of the measured cartilage was not known. The purpose of this study was to investigate whether there is a relationship between the in situ measured compressive stiffness, the histological stage of degeneration, and the biochemical composition of articular cartilage.

DESIGN

Instantaneous compressive stiffness was measured for the articular cartilage of 24 human cadaver knees. Additionally, biochemical composition (total proteoglycan and collagen content) and histological appearance (according to the Mankin score) were assessed for each measurement location.

RESULTS

Despite visually normal surfaces, various histological signs of degeneration were present. A high correlation between Mankin score and cartilage stiffness was observed for the lateral patellar groove (R(2)=0.81), the medial (R(2)=0.83) and the lateral femoral condyle (R(2)=0.71), whereas a moderate correlation was found for the medial patellar groove (R(2)=0.44). No correlation was observed between biochemical composition and cartilage compressive stiffness.

CONCLUSIONS

Our results are in agreement with others and show that the instantaneous compressive stiffness is primarily dependent on the integrity of the extracellular matrix, and not on the content of the major cartilage constituents. The high correlation between stiffness and Mankin score in mild osteoarthrosis suggests that the stage of cartilage degeneration can be assessed quantitatively with the hand-held indentation probe. Moderate and severe case of osteoarthrosis remains to be investigated.

The axial view to measure posterior laxity of the knee. A mathematical analysis

Posterior laxity of the knee can be assessed clinically, but interpretation of the amount of displacement is highly subjective. Mechanical methods are more efficacious for measuring anterior laxity. Radiologic techniques are available for measurement in a lateral projection, but some variables may interfere with their accuracy. We undertook a trigonometric analysis of the axial view to confirm that it can be used to reliably measure posterior displacement. The ideal radiologic conditions consist of 80 degrees of knee flexion in both knees maintained with a knee support and a 26 degrees x-ray beam incidence with respect to the tibia. Although such accuracy is rarely obtained in routine clinical practice, even with a variability of +/- 10 degrees in the x-ray beam incidence the error factor will be less than 10%. Such a degree of error is in the same range (+/- 2 mm) as noted by investigators using the lateral radiograph to measure anteroposterior displacement. We believe that our study validates the use of a single axial radiograph of both knees to assess the state of the posterior cruciate ligament of an injured knee as compared with a normal knee.

The Burch-Schneider antiprotrusio cage in acetabular revision surgery: a mean follow-up of 12 years

A total of 38 acetabular revisions using a Burch-Schneider antiprotrusio cage in 37 patients (18 women and 19 men), with a mean age at surgery of 75 years (range, 55-88 years), were evaluated retrospectively with a mean follow-up of 12 years (range, 8-21 years). In 2 cases with total hip dislocation and in 1 case with a deep infection, revision of the antiprotrusio cages was required. Defining every revision of the antiprotrusio cage as the endpoint of survivorship, the antiprotrusio cage showed a survival rate of 92% after 21 years. Clinical evaluation of the surviving patients showed a mean Harris hip score of 76 points (range, 20-96). Radiologic evaluation revealed that 1 antiprotrusio cage was loose and that 4 femoral stems were loose. The Burch-Schneider antiprotrusio cage compares favorably with other devices with regard to long-term implant survival rate.

[Knee injuries in general practice]

Careful technique of examination of the knee joint allows to establish the diagnosis of the most frequent knee joint injuries already through simple clinical and radiological evaluation: Recurrent dislocation of the patella with the Apprehension sign; meniscal injuries with the test of McMurray, pain on the joint line and pain on passive hyperextension; the anterior cruciate ligament tear with Lachman's sign and the Pivot Shift test and posterior cruciate injury with the Sag sign. Further imaging techniques allow to establish a definite diagnosis, which has replaced in many cases the classical, purely diagnostic arthroscopy. Thanks to careful aspiration of the knee joint the patient can be referred with a more precise diagnosis to the traumatologist and orthopaedic surgeon. Meniscal lesions don't have to be treated as emergencies with exception of the locked knee. Equally, in presence of a fresh tear of the anterior cruciate ligament a delay of surgery for eight weeks may be beneficial, be it only to rehab and prepare the knee joint for surgery. Posterior cruciate ligament tears should only be treated by a few centers, since they demand a high degree of experience. The same accounts for the new techniques for the treatment of cartilage lesions like the mosaicplasty or the autologous chondrocyte implantation.

The effect of knee position on the reproducibility of measurements taken from stress films: a comparison of four measurement methods

We evaluated the accuracy of four different means of radiographic measurement of anteroposterior translation in the knee joint. The tests were performed in normal knees, in knees lacking the anterior cruciate ligament, and in knees lacking both anterior and posterior cruciate ligaments; the knees were obtained from cadavers. It is difficult to define landmarks and to perform exact measurements, and we sought to determine which of the four methods is the most accurate. In particular, we examined the effect of various degrees of rotation and flexion on the positional relationships of the landmarks of the tibia and the femur.

Treatment of proximal humerus fracture using multiple intramedullary flexible nails

A total of 61 patients with a proximal humeral fracture was treated between January 1996 and March 1998 by closed reduction and fracture fixation with intramedullary Prévot (or Nancy) nails. Of these, 28 female and 25 male patients with a mean age of 52 years (range 3-91 years) were reviewed clinically and radiologically with a mean follow-up of 17 months (range 4-30 months). The mean Constant score was 63, the mean Neer score 74 and the mean visual analogue scale (VAS) 73. The 14 patients under 24 years old achieved a Constant score of 86, a Neer score of 99 and a VAS of 97, while 13 patients aged between 25 and 60 years had a Constant score of 67, a Neer score of 75 and a VAS of 71. The 26 patients older than 61 years had a Constant score of 48, a Neer score of 61 and a VAS of 61. One patient with total and 6 with partial humeral head necrosis as well as 5 pseudarthroses were noted. Proximal nail perforation of the humeral head due to fracture collapse was seen in 22 cases. Complications were more frequently observed in the elderly. End results were not related to the type of fracture. This minimally invasive technique decreases the rate of occurrence of avascular necrosis of the humeral head. However, fractures are not sufficiently stabilised, mainly because of bone loss induced by impaction and osteoporosis. Bone loss remains an unsolved problem, and alternative methods such as the use of bone substitute combined with minimally invasive techniques should be studied.

Accumulation of irrigation fluid in the calf as a complication during high tibial osteotomy combined with simultaneous arthroscopic anterior cruciate ligament reconstruction

Extravasation of irrigation fluid during arthroscopy is a well-known complication. We report a case of accumulation of fluid into the calf during open wedge high tibial osteotomy combined with simultaneous arthroscopic anterior cruciate ligament (ACL) reconstruction. The main cause for fluid extravasation was the drilling of the tibial tunnel, which allowed the fluid to cross the osteotomy gap and invade the flexor compartments. Although an elevation of the intracompartmental pressure was measured, there was no clinical evidence of compartment syndrome. A subcutaneous release of the flexor compartment of the leg was performed. The patient suffered no further sequelae. High tibial osteotomy combined with simultaneous arthroscopic ACL reconstruction has to be performed carefully, and potential complications must be detected immediately to prevent compartment syndrome.

Arterial injury during revision total knee replacement. A case report

A case of an anatomical variation of the arterial vessels in the popliteal fossa, leading to a vascular transection during a total knee revision is presented. The authors believe this complication should be considered in all cases of knee revision surgery.

Knee joint simulator: an anatomical reconstruction of the joint surfaces and of the ligamentous structures of the knee joint for teaching purposes

A knee joint simulator with anatomical reconstruction of the joint surfaces and of the ligamentous structures was built for teaching purposes. With this simulator it is possible to demonstrate the anatomy, physiology and kinematics of knee ligaments, to teach and learn how to conduct ligamentous instability tests and to demonstrate the effect of knee ligament reconstructive surgery.

Growth disturbances after injuries of the proximal tibial epiphysis

Proximal tibial epiphyseal fractures are very rare. Partial growth arrest of the physis can cause important axial malalignment in the frontal or the sagittal plane or both, with subsequent shift of the weight-bearing axis onto the injured compartment of the knee joint. To detect the exact extent of the deformity, comparative radiographs of the contralateral side in two planes using long films as well as standing whole leg orthoradiographs are desirable. Accurate measurements in our series of six patients revealed deformities in two, which required secondary surgical correction.

Anterior cruciate ligament graft positioning, tensioning and twisting

This paper reports on a scientific workshop to study anterior cruciate ligament (ACL) reconstruction. The aim is to present recommendations for ACL reconstruction methods that will be of use for surgeons. A study of knee anatomy and graft placement concluded that the tibial attachment must be posterior enough to avoid graft impingement against the femur, and methods to attain this were presented. On the femur, poor graft placement leads to excessive changes of the graft attachment site separation distance as the knee flexes, and the worst case corresponds to the attachment being too far anterior. It was agreed that there were typical patterns of graft tension changes as the knee flexes, and that grafts should be tensioned close to full knee extension. A typical tensioning protocol would be 60 N tension applied at 10 degrees of flexion. It was recognised that graft remodelling caused uncontrollable tension changes post-operation. Graft twisting, to recreate the anatomical spiral of ACL fibres seen in the flexed knee, was also discussed.

[Complex knee trauma--cartilage injuries]

Traumatic cartilage defects of the knee joint occur in an isolated way due to contusions or due to shear forces as a combined injury with ligamentous damage. They must be documented according to localisation, surface involved and depth. In the adult, only the fragment extending into subchondral bone can be refixed. Purely cartilagineous lesions heal spontaneously under partial repair with fibrocartilage; this can equally be surgically stimulated through surgical drillholes or impaction fractures with awls and pins. Since fibrocartilage is known to be mechanically insufficient and is often not resulting in sufficient sports- and working capacity newer methods and are getting more and more popular enabling the induction and production of hyaline or hyaline-like cartilage. Osteochondral transplantation from the own knee as plugs forming a mosaic has the advantage of being readily available for limited surface size. Repair to a hyaline-like cartilage using a chondrocyte suspension is also possible, and is used for bigger surfaces or defects, it needs however two operations. In the long term it will become the method of choice for defects over 4 cm2.

[Managed health care--second opinion from the viewpoint of Swiss orthopedists]

Health Care reform rapidly changes the US health system and enters our "free system" with various aspects. The understanding of the buzzwords in managed care and the so-called managed competition are the context for making informed decisions about our future. We must develop at least a rudimentary understanding of the ways many types of collaborative efforts and managed care organisations evolve. We must know to ask the right questions and hopefully find the correct answers for the benefit of our patient.

Sequential intramedullary nailing of open tibial shaft fractures after external fixation

We reviewed 32 tibial shaft fractures in 31 patients treated with sequential intramedullary nailing after primary external fixation. There were 30 open fractures and 2 closed injuries with severe blunt trauma requiring fasciotomy. Fifty per cent of the fractures were classified as Gustilo type III A and B injuries. The mean external fixation treatment averaged 6.6 weeks, and secondary intramedullary nailing was done on average 7.4 weeks after injury. In 50% of the fractures, secondary nailing was done at the same procedure as removal of the external fixation. Overall, the incidence of osteomyelitis and non-union was 3.1% each and of malunion 19%. The time to full weight-bearing averaged 31.2 weeks. The results were separately analyzed according to Gustilo types and subtypes. In the Gustilo type III B injuries, the incidence of osteomyelitis and non-union was 11%, while malunion occurred in 33%. The time to full weight-bearing averaged 53 weeks. These results support the conclusion that this treatment modality is a valid alternative to other treatment options. However, previous pintract infections should be regarded as a contraindication for secondary nailing.

[Orthopedic examination techniques of the knee joint--basis for diagnosis and indications]

The work up of indication is the aim of each thorough examination. Using the example of the knee joint, we subdivide into five group of diagnosis: anterior knee pain (femoropatellar syndrome), intraarticular derangement, osteoarthritis, infectious and rheumatoid arthritis, forms of bursitis and tendinitis. Clinical signs, diagnosis and natural history are listed, which present the basis of indication.

[Shaving of the cartilage: how much is healthy?]

The shaving of the knee joint can only help patients, who suffer from gonarthrosis, if the tissue, whether it is a mechanical part of hindering cartilage or a part of meniscus, is removed parsimoniously. An improvement is reached through the removal of the mechanical obstacles and also through a washing of the joint and lessening of the painful articular irritation. A cartilage that has been treated by a superficial shaving is not able to regenerate. A deeper shaving with a removal of the subchondral bone leads to a partial reconstitution of a substitute cartilage (fibrous cartilage), according to the age of the patient and to the alignment of the knee joint. This regeneration is not necessarily accompanied by a relief of pain. Nevertheless, the substitute cartilage does not attach itself firmly with the near-lying hyaline cartilage. At the same time the fibrous cartilage supports weight with difficulty and degenerates rapidly. The indication of the shaving of the knee joint should only be applied by exception and be reserved for middle-aged patients with a gonarthrosis and with signs of mechanical stocking.

[The value of corrective osteotomies--indications, technique, results]

Corrective osteotomies around the knee joint gained wide acceptance in the treatment of unicompartmental osteoarthritis of the knee joint despite the improvements in total and partial knee arthroplasty. The combination of axial malalignment of the lower limb with degenerative changes of one femorotibial compartment accentuates the stress onto the damaged cartilage with subsequent increase in the magnitude of axial deformity. The reduction of stress can be achieved by realignment of the leg, which in turn redistributes the forces to more normal areas of the joint. The main goals of the osteotomy include relief of pain and improvement of function. Careful patient selection and assessment as well as a precise surgical technique enable the surgeon to more predictive and improved clinical longterm results. The ideal candidate for a corrective osteotomy is in the sixth or seventh decade of life with a clearly localized, activity-related knee pain, axial malalignment of the leg and radiologically unicompartmental degenerative arthritis. Nevertheless, the patient's activity level and his personal expectations after the procedure are worth to be discussed in context with other treatment possibilities. As with prosthetic replacement, the patient has to understand that the surgical procedure will not provide a normal joint: but "buying time" with an osteotomy may be a viable concept.

High tibial osteotomy alone or combined with ligament reconstruction in anterior cruciate ligament-deficient knees

High tibial osteotomy (HTO) is widely accepted as a treatment option in patients with medial unicompartimental osteoarthritis (OA) and varus morphotype of the knee. We increasingly see younger patients with a chronic anterior instability, an additional varus morphotype and beginning medial OA. Treatment options for these patients are not clear up to now. In this clinical study we compare for the first time three different treatment rationales and introduce a concept of symptom-oriented surgery in young patients with medial OA and chronic anterior instability.

MATERIALS/METHODS

Between 1984 and 1994 30 patients were treated with a medical unicompartimental OA and chronic anterior instability of the knee. Patients were grouped into three different groups according to treatment. 1) only HTO was performed. 2) HTO and simultaneously an ACL-reconstruction and 3) HTO and 6-12 months later an ACL-reconstruction was performed. 27/30 patients were available for follow-up. All patients had an arthroscopy before surgery. Evaluation was done according to the IKDC-protocol and X-ray documentation.

RESULTS

Pain was a major problem in all patients. None of them was completely pain-free. 8/27 patients had pain even with light activities. This included 1/11 patients of group 1, 3/8 of group 2 and 4/8 of group 3. 9/27 patients had stable knee joints with a Lachman-test of 3-5 mm. No patient had a Lachman test < 3 mm. 3/11 patients of group 1, 3/8 of group 2 and 2/8 of group 3 had a Lachman test of 5-10 mm. A positive pivot-shift could be found in 9/27 patients. 2/11 of group 1, 4/8 in group 2 and 3/8 in group 3. The overall IKDC-score improved in 23/27 patients, one patient remained unchanged, two deteriorated. Radiologically a slight progression of OA could be seen in all patients. Radiological signs of OA and pain did not show any correlation. There was, however, a significant rate of postoperative complications involving 4/11 patients of group 1 and 3/8 of group 3. There were 6 major complications in 5/8 patients in group 2. Nevertheless overall patient satisfaction was high. 25/27 patients would undergo the procedure again.

CONCLUSION

HTO is a good treatment option for younger patients with medial OA and chronic anterior instability of the knee. These patients pose a high challenge to diagnostic and operative skills of the surgeon. Main symptoms of these patients have to be analysed clearly in terms of instability and pain. In patients aged 40 and older an HTO alone is an excellent treatment option with reproducibly good results. In younger patients we advise an HTO first. If instability persists, an ACL-reconstruction can be done 6-12 months later. One has to be aware that a simultaneous combined procedure has a significant complication rate. Hence if a simultaneous combined treatment is planned the surroundings including surgical technique, rehabilitation and patient compliance have to be ideal. These young patients need an activity counselling in order to realise that their knee joint has suffered significantly from the injury and ongoing high physical demands on their knee joint.

Long-term results of arthroscopic meniscal repair. An analysis of isolated tears

From 1984 through 1986 we performed 54 arthroscopic meniscal repairs on patients with anterior cruciate ligament-stable knees. We evaluated the repair results of 52 of these patients at an average followup of 7.5 years. In 40 patients the meniscal repairs had not failed and these patients were examined clinically and radiographically; in 25 cases, magnetic resonance imaging was also performed. Significantly more failures (P < or = 0.05) occurred when the rim width of the tear was greater than 3 mm and when the tear was repaired with resorbable sutures. Conversely, the following factors were found to favorably influence meniscal healing (P > 0.05); time from injury to surgery less than 8 weeks, patient age less than 30 years, tear length less than 2.5 cm, and tear in the lateral meniscus. The overall failure rate after 7.5 years was 27% (14 of 52); 64% (9 of 14) of the failures occurred in the first 6 months after repair. The clinical and radiographic evaluation of the successfully repaired knees showed that 90% (36 of 40) had normal knee function; the remaining 10% (4 patients) had nearly normal knee function. Magnetic resonance imaging, however, showed a persisting grade 3 or 4 lesion in 96% (24 of 25) of the successfully repaired menisci and is therefore not reliable in assessing meniscal healing.

Use of the ipsilateral vascularised fibula for tibial reconstruction

Between 1989 and 1994 we used a vascularised ipsilateral fibular graft in 24 patients with segmental tibial defects. We report 12 patients with a minimum follow-up of two years. The graft was either transposed medially or inverted on its vascular pedicle. Full weight-bearing was achieved at between four and seven months. We had few complications and consider that the use of this method is a valuable option in reconstruction of the tibia.

Use of the ipsilateral vascularised fibula for tibial reconstruction

Between 1989 and 1994 we used a vascularised ipsilateral fibular graft in 24 patients with segmental tibial defects. We report 12 patients with a minimum follow-up of two years. The graft was either transposed medially or inverted on its vascular pedicle. Full weight-bearing was achieved at between four and seven months. We had few complications and consider that the use of this method is a valuable option in reconstruction of the tibia.

Three-dimensional dynamic AO external fixation of distal radial fractures--a preliminary report

External fixation of unstable and intra-articular distal radial fractures has become increasingly popular. Dynamic external fixation, allowing movement of the wrist during the fixation period, is a relatively new approach which may further improve functional end results. To permit early functional treatment, the small AO external fixator was supplemented by a joint allowing all three degrees of rotational freedom. The centre of rotation is located at a point outside the device and lies approximately in the head of the capitate. With the natural centre of wrist rotation coincident with that of the fixator, admissable movements of the wrist include both flexion-extension and radio-ulnar deviation, without threatening fracture reduction. In vitro testing and initial clinical experience with a prototype are encouraging. Several improvements of the original design have been made and a multicentric clinical study is scheduled for further evaluation of the new dynamic external fixator.

Positioning of the posterior cruciate ligament

The isometric position in ligament reconstruction is the one in which there is little or no change in the length of the graft with range of motion of the joint. It varies according to the positions of the tunnels that will become the attachment sites of whatever graft is being used. Better understanding of this concept that greatly improved the surgical results of intra-articular reconstructions of the anterior cruciate ligament. Unfortunately, the results of posterior cruciate ligament (PCL) reconstructions have lagged behind. A better understanding of the isometry of the PCL and how it relates to the positioning of a graft at the time of reconstruction should help improve the situation. The current scientific studies on the PCL as they relate to isometry are evaluated and summarised in this paper. The tibial isometric point was universally less sensitive to changes in position than was the femoral isometric point. However, all the points that were evaluated for the tibia fell within the normal insertion area of the PCL. This has important ramifications when extrapolating these laboratory studies to the operating room, where it is imperative to get the tibial tunnel or attachment site distal enough on the tibia so that it will be in the usual anatomic location of the PCL. There is less uniformity when it comes to the femoral isometric point, but once again the isometric point from each of the studies fell within the normal anatomic femoral attachment site. The differences between the selected points may be explained by the different study designs.

Development of the small AO fixator to the current set

An indirect system to reduce and hold comminuted fractures of the distal radius was developed in the mid 1970's starting with a simple threaded distraction rod and advancing to a versatile system of rods and universal clamps. This system has gained wide acceptance since then and is used for the wrist joint and for other indications in surgery of the hand, the upper limb, the foot and in paediatric orthopaedics.

Twelve years follow-up of fractures of the distal radius treated with the AO external fixator

From 1977 to 1982 a total of 55 patients suffering comminuted fracture of the distal radius were treated with the external fixator. Fifty of these were followed up in 1983/85 and 32 of them were available for assessment in this study (1992). The follow-up period was 11.6 years on average. All patients had suffered an intra-articular fracture (91% a C-fracture, 9% a B-fracture according to the AO classification), 27 patients had also fractured the ulnar styloid process and in 11 a dye-punch fragment was present. Both wrists were assessed on the basis of case history, clinical examination, radiographs in two planes and visual analogue scales (VAS). The results were evaluated using established scoring systems. On the Gartland and Werley scale 75% of the results were good or very good, 63% according to Castaing. In general, there was no statistically significant difference between the results of this study and those of 1983/85. It could be demonstrated that there was a relationship between arthritis as a late complication and the existence of an intra-articular step-off of at least 2 mm at implant removal. This also has a negative influence on the range of motion and strength. Radial shortening affects the functional result whereas a die-punch fragment does not. On VAS patients identified performance restriction and disability as the worst consequences of the accident; these criteria correlated best with the results of objective evaluations. In contrast, patients were more satisfied with the result of treatment than would be expected from the objective analyses. The overall results indicate that exact reduction was extremely important. Long-term follow-up showed that the use of the external fixator in the treatment of comminuted intra-articular fractures of the distal radius was an adequate method. Prospective and possibly multicentric studies would be required to investigate more detailed relationships between treatment and long-term results.

Avascular necrosis following traumatic hip dislocation in an 8-year-old boy

Avascular necrosis of the femoral head as a complication of a hip location that is caused by minor trauma and is promptly reduced is uncommon in young children. The incidence appears to be from 3% to 6% if reduction is performed within the first 4 h. However, if it does occur, a significant incidence of degenerative joint disease should be anticipated in the patient's later life. As a possible way of surgical treatment, an intertrochanteric and periacetabular osteotomy should be considered to minimise sequelae. Follow-up must be continued until skeletal maturity is reached.

[Diagnosis of acute and chronic injuries of the knee joint]

Following a general review of the basic principles of knee examination, the specific instability tests of the different ligaments are explained. The pathophysiology, the pathomechanic and the diagnostic evidence of these instability tests are shown. The diagnosis of meniscal and cartilaginous lesions are not discussed.

[Therapy of posterior and posterolateral knee instability]

The natural course after posterior cruciate ligament (PCL) tear is a slow process of degeneration starting in the medial compartment. Functional disability is mainly present in those instabilities that are combined with posterolateral insufficiency. The surgical treatment at present mainly addresses these combined types of posterior-posterolateral instability. It is generally agreed that suture of the torn PCL alone is insufficient and augmentation with autologous structures, such as the patellar ligament, are mandatory. Synthetic augmentation to facilitate after treatment is another adjunct. Because of the difficulty of precise tibial tunnel placement a two-stage procedure is advocated, an anterior approach with the patient supine being used for femoral graft placement. If a posterior approach with the patient prone is used, a straight posterior incision is made between the two heads of the gastrocnemius and the neuromuscular bundle. With this approach the tibial bone block is placed in a trough. The accuracy of graft placement and the immediate functional aftertreatment facilitated by the use of osseous fixation of a synthetic augmentation device at both ends have made better results of surgical reconstruction of the PCL possible.

Static external fixation of the wrist

Historical evolution in concepts, indications, application, reduction techniques, and the rehabilitation program and complications of external fixation of the wrist are discussed. Indirect reduction techniques using overdistraction and flexion are recommended. Additional stabilization of the epiphysis allows immediate reduction of overdistraction, thus eliminating the potential complications related to overdistraction. Used with the due attention to detail, external fixation of the wrist is a rewarding and efficient treatment method.

Radiological analysis of normal axial alignment of femur and tibia in view of total knee arthroplasty

Alignment of the anatomical and mechanical axes of the lower extremities was analyzed using standardized radiographs in two series of 66 femur and 44 tibia specimens. A new anatomical axis, the distal femoral anatomical axis, was introduced. This axis corresponds to the overall femoral anatomical axis and encloses a valgus angle of 6 degrees with the mechanical axis of the femur. It allows for design of shorter intramedullary guiding instruments that will still be in congruency with true femur geometry. Comparison with computerized calculations of angles on computed tomography scans on a series of 38 bones shows a high precision of measurement on standard radiographs in neutral rotation.

Treatment of complex tibial shaft fractures. Arguments for early secondary intramedullary nailing

In 135 cases of mainly open tibial shaft fractures treated primarily with external fixation, 73 patients (54%) were treated exclusively with external fixation; osteomyelitis occurred in 8.2%, nonunion in 8.2%, and malunion in 32.8%. Later sequential plating was performed in 38 patients (28%), and in 24 patients (18%) secondary intramedullary nailing. Patients with delayed nailing after primary external fixation had the lowest incidence of osseous infection (4.1%) and nonunion (4.1%), the lowest malunion rates under strict criteria (24%), and a significantly shorter healing time (21.5 weeks versus 33.4 weeks after secondary plating and 30.2 weeks after treatment with external fixation alone). Patients treated with secondary plating had osseous infection in 10.2%, nonunion in 7.8%, and malunion in 29.3%. Changing to an intramedullary nail after primary treatment of open tibial shaft fractures with external fixation was a more effective way to treat these fractures than definitive treatment with external fixation alone or delayed secondary treatment by plating. Sequential nailing can be performed as early as one to three weeks after trauma without the necessity of a safety interval between the removal of external fixation and intramedullary nailing to prevent infection.