Computer assisted navigation is known to improve tunnel placement in ACL reconstruction even compared to use of direct arthroscopic view due to image distorsion by the wide angle optics in the arthroscope. However the earlier software and instrumentation has been relatively cumbersome. The use of new materials and further software elaboration has allowed to increase the navigational precision and to accommodate more different ACL repair techniques. The relevant developments of such an upgrade which in addition allows stability testing before and after the repair are presented.

Current issues being debated in ACL reconstruction include injury prevention, graft choice, graft positioning, graft fixation, graft remodelling and rehabilitation. Tissue engineering, the alteration of biological mechanisms by application of novel proteins, enzymes and hormones, is rapidly changing the way we approach all aspects of surgery. Tissue engineering techniques in ACL/PCL reconstruction focus on new biosynthetic ACL material, fixation of soft tissue grafts to bony tunnels and graft remodelling

OP-1 is recombinant human Osteogenic Protein 1 (BMP-7). It is a member of the Transforming Growth Factor β (TGFβ) super family. OP-1 promotes the recruitment, attachment, proliferation and differentiation of pluripotential mesenchymal stem cells. It promotes both osteogenesis and chondrogenesis. The carrier is highly purified bovine bone type 1 collagen, which provides an osteoconductive matrix.

We have completed a study assessing the use of OP-1 as a means of enhancing early biological fixation of soft tissue grafts within bone tunnels in a sheep ACL model.

We have commenced a clinical trial using OP-1 in adult ACL reconstruction, believing that OP-1 will enhance early biological graft fixation, and hence, improve clinical results, speed up rehabilitation and prevent tunnel widening.

Other studies have shown the beneficial effects of BMP-2 on an extraarticular bone tendon fixation model, the use of TGF-B to enhance graft remodelling and the application of gene therapy to deliver BMP’s for enhanced graft fixation.

Several projects are underway looking at creating biosynthetic ACL grafts using tissue engineering techniques. As opposed to purely synthhetic grafts, bioACL grafts are made of a collagen scaffold, allowing for remodelling and revascularisation.

ACL reconstructive surgery is constantly evolving. Tissue engineering may provide us with a means of minimising morbidity, accelerating rehabilitation and improving the clinical outcome following this common surgery.

Purpose

Factors that contribute to early and late re-operation after cruciate reconstruction (CR) have not been evaluated on a population level in a public health system. After surgery patients are at risk for knee stiffness, infection or early graft failure prompting revision. Long-term, ipsilateral revision CR, contralateral CR and potentially even joint replacement may occur. Population research in total joint replacement surgery has demonstrated an inverse relationship between complication/failure rates and surgeon procedural volume. We hypothesized that in Ontario, younger patient age and lower surgeon volume would increase the risk of short and long-term re-operation after CR.

Purpose

Twelve case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential stress riser for fracture formation. The recent increase in double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the stress riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a stress riser to fracture and that this effect increases with the size of the tunnel (8mm versus 10mm) and with the number of tunnels (one versus two).

Objectives. Congenital cruciate ligament deficiency is a rare condition that may occur in isolation or in association with longitudinal limb deficiencies such as fibular hemimelia or proximal femoral focal deficiency. Often anomalies of the menisci and their attachments can be very abnormal and impact on surgical management by standard techniques. Arthroscopic surgical knee reconstruction is undertaken to improve symptomatic instability and/or to stabilise and protect the knee for future planned limb lengthening surgery. The aim of this study is to evaluate the arthroscopic findings of patients undergoing surgery for congenital cruciate ligament deficiency, and specifically to determine the frequency and types of meniscal anatomical variations seen in these cases. Methods. Patients undergoing surgery for congenital cruciate ligament deficiency were identified from a prospectively collated database. Diagnosis was confirmed through review of the clinical notes and imaging. Operative notes and 4K saved arthroscopic images and video recordings for these cases were reviewed. Results. Over a six-year period (July 2017 – September 2023), 42 patients underwent surgery for congenital ligament deficiency and tibiofemoral instability (45 surgical episodes). Median age of patients at time of surgery was 10 years (range 4 – 17 years). The most frequent diagnosis was congenital longitudinal limb deficiency syndromes in 27 cases, with the most frequent being fibular hemimelia. Isolated congenital ligament deficiency without any other associated extra-articular manifestations occurred in 11 cases. Absence of meniscal root attachments or hypertrophy of meniscofemoral ligaments acting as ‘pseudo-cruciates’ were seen in over 25% of patients. In isolated ACL deficiency these were injured causing onset of instability symptoms and pain following trauma. Often these abnormal structures required addressing to allow surgical reconstruction. Conclusions. Our findings demonstrate that there are often meniscal variations seen in association with congenital absence or hypoplasia of the cruciate ligaments. In these patients hypertrophied meniscofemoral ligaments may act as cruciate-like structures and play a role in providing a degree of sagittal plane stability to the knee. However, when the knee becomes unstable to the point that cruciate ligament reconstruction is indicated, these meniscal variants may often require stabilisation using complex meniscal root repair techniques or variations to standard cruciate ligament reconstruction techniques to accommodate the variant anatomy

The purpose of this study was to quantify tibial tunnel enlargement at 3-, 6- and 12-months post-anterior cruciate ligament reconstruction (ACLR), and evaluate the magnitude of tunnel widening with use of a Poly (L-lactic Acid) interference screw (PLLA (Bioscrew XtraLok, Conmed, New York)) compared to a Poly (L-lactic Acid) + tricalcium phosphate interference screw (PLLA+TCP (GENESYS Matryx screw comprised of microTCP and 96L/4D PLA, Conmed, New York)). This was a prospective randomized controlled trial with two parallel groups. Eighty unilateral ACL-deficient participants awaiting ACLR surgery were recruited between 2013 and 2017 from the clinic of a sole fellowship trained orthopaedic surgeon. Patients had to be skeletally mature and less than 45 years old, with no concomitant knee ligament injuries requiring surgery, chondromalacia, or previous history of ipsilateral knee joint pathology, surgery or trauma to the knee. Participants were randomized intra-operatively into either the PLLA or PLLA+TCP tibial interference screw fixation group. Study time points were pre-, 3-, 6-, and 12-months post ACLR. Participants underwent x-rays with a 25 mm calibration ball, IKDC knee assessment, and completed the ACL-Quality of Life score (ACL-QOL) at each visit. Measurement (mm) of the most proximal and distal extents as well as the widest point of the tibial tunnel were taken using efilm (IBM Watson Health) and were standardized relative to the calibration ball. A contrast inverter was used to determine clear borders based on contrast between normal and drilled bone. In addition, a subjective evaluation of the tunnel was conducted looking for bowing of the borders of the tunnel or change in tunnel shape, categorizing the tunnel as widened or not widened. Differences between groups at each time point were evaluated using independent t-tests corrected for multiple comparisons. Tunnel width was also compared as a percentage of actual screw size at 12-months post-operative. Categorical data were compared using Fisher's Exact Test. Forty participants were randomized to each group with mean age (SD) of 29.7 (7.6) and 29.8 (9.1), for PLLA and PLLA+TCP, respectively. There were no differences between groups in age, gender or ACL-QOL. There were no differences found between groups at any time point in either tunnel width measurements or tunnel width as a percentage of actual screw size. The greatest difference between groups was noted in the measurement of the widest point on lateral x-ray view with a mean difference of 11%. Based on subjective evaluation of tunnel shape, three participants had visible widening in the PLLA group, and two in the PLLA+TCP group (p=NS). No differences in tunnel widening were identified between ACL reconstruction patients using a PLLA interference screw compared to a PLLA+TCP screw for tibial fixation up to 12-months post-operative

Introduction: Accelerated rehabilitation programs following ACL reconstruction require adequate fixation strength. Staple fixation of grafts outside the tibial tunnel has been shown to have fixation strength comparable to interference screws. The use of bioresorbable polymer implants has potentially significant advantages especially if revision is required. The purpose of this study was to evaluate a new bioresorbable fixation staple using an ovine model. Materials and Methods: Forty-eight mature sheep underwent unilateral cranial cruciate ligament (CrCl) reconstruction. The reconstruction comprised a loop of superficial digital flexor tendon (autograft) joined to a prosthetic ligament (LK-15). Femoral fixation was by endobutton. Tibial fixation of the LK-15 was with either a new Poly-L-lactic acid (PLLA) staple (Zimmer Japan/Gunze Ltd.) or a Cobalt-chrome (CoCr) staple. Biomechanical and histological responses were evaluated at 0, 6, 12 and 24 weeks. Results: At all times post-reconstruction there were no significant differences between staple types for construct strength or stiffness (p> 0.05). The staple was not the site of reconstruction failure, and there were no adverse tissue reactions, for either staple type. Fibrous tissue was more often found at the interface of the CoCr staple. Conclusions: The PLLA staple performed biomechanically as well as the metal staple for tibial fixation of cruciate ligament reconstructions. There were no significant observable adverse histological responses over the time intervals examined

Aims: Congenital aplasia of the knee cruicate ligaments is considered to be a very rare anomaly of musculoskeletal system. It is frequently found in conjunction with other deformities. Proximal femoral focal deficiency (PFFD) is a congenital defect which is almost always accompanied by cruciate ligament defect. The aim of our study was to determine the occurence of cruciate ligament aplasia arthroscopically. Method: Arthroscopies of the knee joints were always performed as part of other primary operations for PFFD. In our followed series consisting of 50 PFFD patients, 26 boys and 24 girls, five boys with PFFD classified respectively as Pappas III, VII, VII, VIII and IX and 3 girls with PFFD classified respectively as Pappas III, VII and VIII were examined arthroscopically. Deficiency of cruciate ligaments was also documented in a pateint with the diagnosis of isolated aplasia of the fibula. Changes in the shape of intercondylar area of the distal femur, and aplasia or hypoplasia of the intercondylar ridge of proximal tibia in all PFFD patients were evaluated by an X-ray. Conclusions: In all patients who underwent arthroscopy absence of both cruciate ligaments was proven. Seriousness of the anomaly was inversely related to the degree of classification according to Pappas. None of our patients suffered from problems arising from knee instability. Based on our experience we recommend a reserved approach as far an indication for cruciate ligament reconstruction in PFFD patients is concerned

Post traumatic myositisossificans is a benign condition of heterotropic ossification of unknown aetiology which typically is related to trauma from a single blow or repeated episodes of microtrauma. We describe an unusual case of myositis ossificans which developed as a complication at the donor site for hamstring autologous graft used in open anterior and posterior cruciate repair and posterolateral corner reconstruction in a 15 year old girl. Case report: A 15 year old girl sustained a closed traumatic dislocation of her left knee when she fell from a trampoline. She underwent emergency manipulation under anaesthetic and closed reduction followed by MRI scan which showed a complete disruption of the lateral collateral ligament complex, posterolateral corner injury, complete tears of the anterior and posterior cruciate ligaments and a partial tear of the medial collateral ligament. 13 days later she had an open reconstruction of her anterior and posterior cruciate ligaments with allograft and a repair of popliteus and lateral structures with Larson reinforcement with controlateral hamstring autologous graft. Eight months following open reconstruction the patient represented to her primary care practitioner with a painful lump in the postero-medial controlateral right thigh. MRI study showed that there was a lobulated hypervascular appearance with a thin enhancing rim of low signal on all sequences indicating calcification. An xray revealed a calcified mass consistent with the diagnosis of myositis ossificans. Discussion and conclusion: To date we have found no reported cases of myositis ossificans occurring as a result of surgery to harvest hamstring autograft in the setting of ligament reconstruction about the knee. We believe that this is an unusual complication of the donor site which needs awareness amongst clinicians involved in primary and revision cruciate ligament reconstruction. We suggest that a management strategy of surveillance for this lesion is appropriate and excision biopsy should be reserved for specific indications such as malignant features on imaging or mass effect

Funding for the health service is limited and this inevitably leads to rationing. However, the allocation of funding to different specialities and clinical areas often has no rational basis. The aim of this study was to evaluate the health status of patients on the orthopaedic waiting list. The SF-36 was used as a postal questionnaire and sent to all adult patients on the elective orthopaedic waiting list at our hospital. Demographic data was collected and patients were grouped by intended operation. The health domains of the SF-36 were adjusted for demographic variables and compared to population norms using non-parametric statistical methods. The SF-36 was sent to 1586 patients and 1155 responded (73%). Analysis was undertaken for hip replacement (n=194), knee replacement (n=291), knee arthroscopy (n=232), foot and ankle (n=147) and cruciate ligament reconstruction (n=46). All diagnostic groups had significantly worse (p< 0.05) scores for all domains of health when compared to population norms. Patients awaiting joint replacement had worse disability (p< 0.001) than other groups, particularly for pain and physical function. Patients over 40 years awaiting arthroscopy had disability approaching these levels and those awaiting ACL reconstruction had poor physical function. In general, patients awaiting foot or ankle surgery had better health than other diagnostic groups but still had significant reductions when compared to normal. Health scores were not related to the Townsend index for social deprivation, indicating equity of access within the health service. Patients awaiting hip and knee replacement have worse health than others on the waiting list. The SF-36 could be a useful tool if priority on waiting lists were to be determined by pain and disability rather than waiting time

Anatomy & Biomechanics. Lateral Collateral Ligament (LCL). Primary stabilizer to varus opening. Femoral attachment – proximal/posterior to lateral epicondyle. Fibular attachment – midway along lateral fibular head. Popliteus Complex. Important stabilizer to posterolateral rotation. Stabilizer to varus opening. Popliteus attachment on femur. 18mm anterior/distal to LCL. anterior fifth of popliteal sulcus. Popliteofibular ligament (PFL). originates at musculo-tendinous junction of popliteus. attaches at medial aspect of fibular styloid. Mid-Third Lateral Capsular Ligament. Secondary stabilizer to varus opening. Thickening of lateral midline capsule. Meniscotibial portion often injured. Segond injury. Biceps Femoris Complex. Short head of biceps. Long head of biceps. Lateral Meniscus. Injury Mechanism. Rarely isolated injury. Usually as a combined ligamentous injury. ACL/PLC. PCL/PLC. Knee Dislocation. Hyperextension. Varus blow. Noncontact twisting. Importance of injury. Grade III injuries do not heal. Lead to instability and osteoarthritis. Compromise cruciate ligament reconstructions. Diagnosis of LCL/PLC injury. History. Usually due to varus/hyperextension injuries. 15 % have a peroneal nerve injury. Usually combined ligamentous injury. Clinical exam. Varus stress test. External rotation recurvatum test. Posterolateral drawer test. Dial test. Reverse pivot shift test. Varus thrust gait. Radiographs. MRI. Arthroscopic evaluation. Treatment for acute posterolateral knee injuries. Acute grade I and II injuries. Brace 6 weeks. Full ROM. Partial weight bearing. Acute grade III injuries. Repair/reconstruct within 2 weeks after injury. Attempt anatomic repair. Each structure repaired individually. Consider augmentation in midsubstance tears. Anatomic reconstruction. Treatment For Chronic Grade III Injuries. Assess for varus alignment. Proximal tibial opening wedge osteotomy. Reassess after 6 months for need for soft tissue reconstruction. Anatomic reconsruction of posterolateral structures. Two tailed reconstruction of LCL, PFLand popliteus tendon. Biomechanically restores function of native ligaments

Purpose: The radiological appearances of tibial tunnel enlargement following anterior cruciate ligament reconstruction in the short and medium term have been described. This study compares the tibial tunnel appearances at 1 year and again at 8 years post-operatively in 44 patients, and correlates the findings with the longer term clinical outcome. Patients and Methods: The study was conducted on 44 consecutive patients who had undergone isolated central anterior cruciate reconstruction using a four thickness hamstring technique. All patients were reviewed at one year postoperatively, the assessment including full clinical examination, arthrometer testing and weight bearing AP and lateral radiographs. They were reviewed again at a mean of 8 years (range 5–10 years) post reconstruction. At the 8 year review, full clinical examination, Arthrometer testing, Lysholm and IKDC scoring, Tegner activity level recording were done and standardised weight bearing AP and lateral radiographs were taken. The Tibial tunnel diameters were measured by two independent observers on both one year and 8 year radiographs. The proximal tunnel measurement was made 5 mm from the tibial articular surface and the distal, 5mm from the lower end of the tunnel. Tunnel enlargement was calculated from the known drill size after correction for magnification. The tunnel enlargements were correlated with clinical outcome and the results were analysed statistically. Results: There were 6 failures of stability for which an additional operative procedure had been undertaken. The remaining 38 knees were functionally stable. 28 (75%) had negative Lachman and jerk tests and 34 (90%) had a side to side arthrometer difference of less than or equal to 3mm. The mean tibial tunnel enlargement at one year was 31% at the proximal and 23% at the distal end of the tunnel. At 8 years the enlargements were 20% at the proximal and 13 % at the distal end of the tunnel (p< .001). There were 10 patients (26%) whose distal tunnel diameter at 8 years was less than the initial drill size. Only one of these had a positive Lachman test. This negative association was significant (p< .05). There was no significant correlation between enlargement at the proximal end of the tunnel, the Lysholm score or clinical stability at 8 years. Conclusion: Cruciate ligament reconstruction persists at 8 years. However there was a previously unreported reduction in radiographic tunnel size at the 8 year review and this reduction was significant at the distal end of the tibial tunnel. There was no correlation between tunnel enlargement and functional outcome even at 8 year review

This study evaluated the long term outcome of isolated posterior cruciate ligament (PCL) reconstruction. Thirty patients underwent surgery with hamstring tendon autograft after failing conservative management. At 10 years after surgery patients were assessed with radiographs, full IKDC examination and KT1000 instrumented testing. The mean IKDC subjective knee score was 87 out of a possible 100. Regular participation in moderate to strenuous activities improved from 26% preoperatively to 88% of patients. At 10 years endoscopic reconstruction of the PCL with hamstring tendon autograft is effective in reducing knee symptoms. Patients can expect to continue participating in moderate to strenuous activties over the long term. Osteoarthritis is observed in some patients with 18% showing some loss of joint space which compares favorably with non-operatively managed PCL injuries. This is a successful procedure for symptomatic patients with PCL laxity who have failed conservative management

Knee ligament injury is one of the most frequent sport injuries and ligament reconstruction has been used to restore the structural stability of the joint. Cycling exercises have been shown to be safe for anterior cruciate ligament (ACL) reconstruction and are thus often prescribed in the rehabilitation of patients after ligament reconstruction. However, whether it is safe for posterior cruciate ligament (PCL) reconstruction remains unclear. Considering the structural roles of the PCL, backward cycling may be more suitable for rehabilitation in PCL reconstruction. However, no study has documented the differences in the effects on the knee kinematics between forward and backward pedaling. Therefore, the current study aimed to measure and compare the arthrokinematics of the tibiofemoral joint between forward and backward pedaling using a biplane fluoroscope-to- computed tomography (CT) registration method. Eight healthy young adults participated in the current study with informed written consent. Each subject performed forward and backward pedaling with an average resistance of 20 Nm, while the motion of the left knee was monitored simultaneously by a biplane fluoroscope (ALLURA XPER FD, Philips) at 30 fps and a 14-camera stereophotogrammetry system (Vicon, OMG, UK) at 120 Hz. Before the motion experiment, the knee was CT and magnetic resonance scanned, which enabled the reconstruction of the bones and articular cartilage. The bone models were registered to the fluoroscopic images using a volumetric model-based fluoroscopy-to-CT registration method, giving the 3-D poses of the bones. The bone poses were then used to calculate the rigid-body kinematics of the joint and the arthrokinematics of the articular cartilage. In this study, the top dead center of the crank was defined as 0° so forward pedaling sequence would begin from 0° to 360°. Compared with forward pedaling, for crank angles from 0° to 180°, backward pedaling showed significantly more tibial external rotation. Moreover, both the joint center and contact positions in the lateral compartment were more anterior while the contact positions in the medial compartment was more posterior, during backward pedaling. For crank angles from 180° to 360°, the above-observed phenomena were generally reversed, except for the anterior-posterior component of the contact positions in the medial compartment. Forward and backward pedaling displayed significant differences in the internal/external rotations while the rotations in the sagittal and frontal planes were similar. Compared with forward cycling, the greater tibial external rotation for crank angles from 0° to 180° during backward pedaling appeared to be the main reason for the more anterior contact positions in the lateral compartment and more posterior contact positions in the medial compartment. Even though knee angular motions during forward and backward pedaling were largely similar in the sagittal and frontal planes, significant differences existed in the other components with different contact patterns. The current results suggest that different pedaling direction may be used in rehabilitation programs for better treatment outcome in future clinical applications

Purpose: To introduce modified tibial inlay technique for autogenous bone-patellar tendon-bone (BPTB) posterior cruciate ligament (PCL) reconstruction and evaluate the outcomes of PCL reconstruction by this method. Methods: Fifty patients who underwent autogenous BPTB PCL reconstruction using modified tibial inlay technique were evaluated at average 30.9 months (range 12–52). The outcomes were assessed by stress radiographs, maximal manual test with KT-2000 arthrometer, IKDC grading and OAK knee score. Results: Average side to side difference in push view with Telos stress device decreased from 11.7mm to 3.2mm. Difference in maximal manual test with KT-2000 arthrometer also decreased from 11.5mm to 3.1mm. Final IKDC grading was A in six patients, B in thirty four, C in nine and D in one. Average OAK score improved from 64.3 to 86.4. Conclusion: We consider that the modified tibial inlay technique is a method to reduce technical effort and contribute to satisfactory clinical results in autogenous BPTB PCL reconstruction

The purpose of this study was to evaluate the outcome of posterior cruciate ligament (PCL) reconstruction with a double tunnel technique, using prospective pre & post-operative functional scoring and clinical evaluation. We reviewed those patients who underwent PCL reconstruction between October 2001 and October 2006. 24 patients were identified, 23 male and 1 female. Mean age 30.1 years (range 17–43). Mean follow up 56 months (range 29–86). The commonest mode of injury was football. 3 patients had isolated PCL injuries, 21 had concomitant knee ligament injuries which were treated surgically at the same operation. Patients were prospectively scored pre-operatively and at 3, 6, 12 & 24 months post-op using the Lysholm, IKDC 2000 & KOOS scoring systems. These scores were compared to an injury matched control group who underwent comparable knee ligament reconstructions, but who had intact PCL’s. The knee scores showed a significant improvement in all PCL reconstructed patients post-op (p< 0.05). However, significant differences were found between the PCL reconstructed and PCL intact groups. Both groups had high return to employment and return to sports rates. We describe our method of double tunnel reconstruction. Conclusions: PCL injury is usually associated with concomitant soft tissue knee injuries. PCL deficiency contributes significantly to the morbidity of the multiple ligament injured knee. Reconstruction with the double tunnel technique described gives excellent functional improvement and high rates of return to employment and sports

Introduction Posterior cruciate ligament (PCL) reconstruction has been shown to restore the posterior stability of the knee during posterior drawer tests. However, we have previously published a report showing that a PCL deficient knee has abnormal rotation under load. We hypothesise that a PCL reconstruction does not restore rotational stability to the knee. Methods In-vitro kinematics under simulated muscle loads after PCL reconstruction were measured. Eight fresh-frozen cadaveric knees were tested on a robotic testing system. The system applied a posterior drawer of 130N and a combined quadriceps/hamstrings load (400N/200N) at 0°, 30°, 60°, 90°, and 120° of flexion. Tibial motion with respect to the femur was measured with the PCL intact, resected and reconstructed using an Achilles tendon allograft. Posterior tibial translation (PTT) and internal/external rotation were analyzed using a repeated measures ANOVA. Results PCL deficiency significantly increased (p< 0.05) PTT under posterior drawer. Reconstruction significantly reduced the increased PTT to the level of the intact knee at all flexion angles. Under the muscle load, the deficiency resulted in significantly higher PTT at 60 to 120, and reconstruction did not significantly reduce the increased PTT. PCL deficiency significantly increased external rotation at 90° and 120°. PCL reconstruction did not significantly reduce the increased external rotation caused by PCL deficiency. Conclusions Under simulated muscle loading, PCL reconstruction did not restore the translation and rotation of the tibia, despite restoring posterior stability under posterior drawer. Our data may help to identify the biomechanical factors that lead to the long-term development of osteoarthritis following PCL injury and reconstruction. In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source

Osteochondral autologous transplantation (OATS) is a new technique for the treatment of osteochondral defects. In a prospective randomised study, between November 1996 and June 2000 we used the OATS technique to treat 136 patients (90 male, 46 female) with a mean osteochondral defect of 3.3 cm2. The defect was in the medial femoral condyle in 54 cases, the lateral femoral condyle in nine, the patella in 15, the trochlea in six, the tibial plateau in one, the talus in 29, the tibial plafond in two, the capitellum in four. There were 16 other locations. The procedure was performed either open or arthroscopically. A mean of 2.2 cylinders was transplanted. At the same time, we treated malalignment by high tibial osteotomy (HTO) in 20 patients, and instability by anterior (ACL) or posterior cruciate ligament (PCL) reconstruction in 16. Five patients required reconstruction of both ACL and PCL. The Lysholm score in the lower limbs increased from a preoperative mean of 58.3 (20 to 77) to a mean of 90.2 (70 to 100). Treatment by OATS alone increased the score from 62.9 to 91.6. The combination of OATS and HTO increased the score from 65.2 to 91.6. With additional ACL/PCL reconstruction, the score increased from 49.9 to 82.6. The combination of OATS, HTO and ACL/PCL reconstruction increased the Lysholm score from 55.5 to 85.5. Control postoperative MRI with IV contrast (Gd-DTPA) showed incorporation of all but one cylinder. Complications included one case of arthrofibrosis and sinking of one cylinder. One patient developed regional pain syndrome and three had pain at the malleolar osteotomy site, resolved by screw removal. For four weeks after the operation, 10% of patients complained of pain at the donor side in the lateral femoral condyle. There were no complications related to OATS performed in the upper limbs, and control MRI three months postoperatively showed incorporation of all cylinders. The results are encouraging, and give rise to the hope that this cost-effective and safe new treatment for limited osteochondral defects may delay or even prevent the onset of osteoarthritis