Background and aims. Hallux rigidus in the metatarsophalangeal joint (MTPJ) can be treated with arthroplasty to reduce pain and enhance motion. Few studies have investigated the functionality and the survival of HemiCap arthroplasty. Primarily we aimed to examine the medium to long-term functionality and the degree of pain after surgery. Secondarily the failure and revision rate of HemiCap implants. Methods. A total of 106 patients were operated with HemiCap arthroplasty (n=114) from 2006 to 2014, median age 53 (16 to 80) years, 78 females, 37 dorsal flange (DF) implants. Patient charts were reviewed retrospectively to collect revision data. Pre operative Coughlin/Shurnas arthrosis degree, hallux valgus (HV), intermetatarsalintermetatarsal (IM) and Distal Metaphyseal Articular Angle (DMAA) angles was were measured. Pre- and post operative 3 weeks, 6 months, 1 and 2 year2-year pain levels of the first MTPJ by Visuel Analog Skala (VAS 1–10), American Orthopaedic Foot and Ankle Score (AOFAS 0 to 100 points) and, Range of Motion (ROM), were available for 51 patients. FortysevenForty-seven of the 70 available for reexamination partook in a cross sectional follow up where the Self-Reported Foot and Ankle Score (SEFAS 0–48 points) was added to the Patients Related Outcome Measures (PROMs). Statistics. Kaplan-Meier for survival analysis, adjusted for sex, radiological angles, degree of arthrosis and dorsal flange. Prospective PROMs and ROM compared by paired t-test. Results. At 3, 5 and 7 years we had an mean implant survival of 85%, 83% and 78%. Almost all were revised due to pain, one due to malalignment and one due to loosening of the Hemicap. Dorsal flange, gender, preoperative arthrosis degree, HV, IM or DMAA angles did not statistically influence the result. For those (n=23) that were re-examined, preoperative dorsal ROM changed from mean(sd) 21 (6) to 42 (18) degrees, VAS from 7 (2) to 2 (2) and AOFAS from 61 (11) to 87 (11) (p < 0.001). At mean 5 year follow up (n=47), mean (sd) dorsal ROM was 46 (17) degrees,. AOFAS was 84 (9), VAS 2 (1) and SEFAS 42 (6) points. The dorsal flange made no statistical significant difference for ROM or PROMs, but DF displayed 51 degrees of extension vs. 44 without (p=0.1). Periprostethic lucency (<2 mm) was observed in 27/47. Conclusions. In general, we saw an acceptable implant survival rate. We did not find any predictors that influenced implant failure and the design alterations with the dorsal flange are not evident clinically. Patients who were not revised had significantly less pain, greater ROM, and better overall foot and ankle conditions than preoperatively, but the data are biased by missing numbers and revisions

Background. Severe hallux rigidus can be treated with total or hemi arthroplasty to preserve motion in the 1st metatarsophalangeal joint (MTPJ). Decreased dorsiflexion impairs the rollover motion of the 1st MTPJ and recent studies of patients with 1st MTPJ osteoarthritis show increased plantar forces on the hallux. Objectives. Our aim was to examine the plantar force variables under the hallux and the 1st, 2nd, and 3rd – 5th distal metatarsal head (MH) on patients operated with a proximal hemiarthroplasty (HemiCap) in the 1st MTPJ and compare to a control group of healthy patients. Secondary aims: To examine correlations between the force and the 1st MTPJ range of motion (ROM) and pain. Study Design & Methods. Seventy patients operated with HemiCap were invited. 41 were included, (10 men, 31 women), median operation date 2011(range 2007–2014), age 63(47–78), 37 unilateral and 4 bilateral. Dorsal ROM of the 1st MTPJ was measured by goniometer and by x-ray. Pain evaluated by visual analog scale (VAS 1–10) during daily activities (DA) and during testing (DT). Emed (Novel) Foot Pressure Mapping system was used to measure peak force (N) and force/time integral (N/s) under the hallux, 1st and 2nd and 3–5th metatarsal heads (MH). Statistics: Force variables between operated feet and control group were compared by independent two-sample t-test or Wilcoxon rank sum test. Force variables association to ROM and pain by linear regression models. Results. Median (range) for HemiCap/Control group: Peak force (N): Hallux: 12(1–26)/20(4–30), 1st MH: 17(8–41)/24(14–42), 2nd MH 24(15–37)/28(24–37), 3rd–5th MH: 27(18–36)/30(25–35). Force/time integral (N/s): Hallux: 1(1–4)/4(1–12), 1st MH: 5(2–18)/7(3–11), 2nd MH 8(4–13)/10(7–13), 3rd–5th MH: 9(6–15)/10(8–14). Significant difference between HemiCap patients and healthy controls in peak force and force/time integral was found under the hallux (p<0.01), 1st (p<0.05) and 2nd MH (p<0.05), and max force under the 3–5th MH (p<0.01). Dorsal ROM of the operated feet was 45 degrees (10–75) by goniometer and 41 degrees (16–70) by x-ray. An increase in dorsal ROM decreased the peak force and force/time integral under the hallux (p>0.05) but not under the MHs. Most patients reported no pain (VAS 1: 62% DA, 78% DT), only 2 patients reported VAS>3. No significant correlation between pain and force or force/time integral. Conclusions. A mid-term hemiarthroplasty do not restore the joint motion to normal. The loading patterns are in opposition to AO patients as as assfgjkdfgjkfdgjk the HemiCap patients show a significantly decreased peak force and force/time integral under the hallux compared to the control group and the larger the dorsiflexion achieved postoperatively the smaller the force/time integral becomes. It may reflect a patient reluctance to load the 1st ray and 2nd MH. The plantar forces are not linked to pain. Most report minimal pain, but the pain score is biased by missing numbers and exclusion of revisions

There are many types of arthroplasties for the 1st MTPJ, but still the treatment of advance Hallux rigidus remains controversial. In this study we are reporting the outcome of the North Star hemicap at 6 months. A series of patients under the care of a single surgeon were followed using the Manchester - Oxford Foot Questionnaire (MOXFQ) at 6months post operation, and a satisfaction question was asked. The operations were between August 2011 and August 2013. A total of forty five arthroplasties were implanted in 44 patients. Thirty four of them were female and 9 were male. The average age was 56 years (range 37–77 years). Twenty six out of them (59%) needed an MUA + a local anaesthetic and steroid injection of the prosthetic joint at 2 to 14 months (average 6 months) post implantation. In these patients the MOXFQ was filled at 6months post the MUA and injection. Four of them were left out of the study because they were less than 6months post MUA. One patient had his implant removed and changed to fusion at his request at 14 months post implantation. Forty one patients were satisfied and would recommend the operation, 2 were disappointed with the degree of movement but would still recommend the operation and one had it revised to fusion. The average MOXFQ was 12/64. In conclusion, high percentage of patients needed a second operation, but the scores are reasonably low and almost all patients would recommend it. Further follow up of these patients is needed for at least 5years but the early results are showing it to be a good alternative for fusion

Introduction: Advanced stages of first metatarsophalangeal (MTP) arthritis have traditionally been treated with resection arthroplasty or arthrodesis. Total- and hemiarthroplasty using various prosthetic replacements of the MTP joint, or phalangeal base, have been reported with variable success. A new metatarsal resurfacing system allows for intraoperative joint geometry mapping and placement of a contoured prosthetic.

Methods: Twenty-five patients with advanced stage hallux rigidus were included in this investigation and have undergone metatarsal head resurfacing (HemiCAP® Prosthesis, Arthrosurface Inc., Franklin, MA). The average age of the patients was 51 years. All patients were assessed with the Short Form 36 Health Survey (SF-36) and the American Orthopedic Foot and Ankle Society (AOFAS) clinical rating system for the Hallux, physical examination and radiographic evaluation. The average follow up was 20 months (range: 8 to 28 months).

Results: Postoperative passive dorsiflexion increased on average by 31 degrees from 34 degrees at baseline to 65 degrees at last follow-up. The mean AOFAS score improved from 44.1 to 82.1. The average SF-36 score improved from 81.2 to 96.1. The preoperative visual analogue pain score was reduced from 6.8 to 1.4 at last follow-up. No radiographic evidence of implant loosening, subsidence, or periprosthetic radiolucency has been found to date. No device failures have been encountered. All patients stated they would undergo the procedure again. One patient had a superficial wound break down which resolved with conservative care.

Conclusion: Although long term follow up is still necessary, the current results are very promising providing effective pain relief and improvement in range of motion. Proper implant placement does not affect the sesamoid groove. The procedure is performed with minimal joint resection and preserves viable bone stock, therefore conversion to arthrodesis or resection arthroplasty is possible should the need for further treatment arise.

Osteochondral fracture of the femoral head is an uncommon injury with a high potential for a poor functional outcome. Management is often challenging with limited options. We present two cases in which osteochondral fractures of the femoral head were treated with partial resurfacing using the HemiCAP System (Arthrosuface, Franklin MA, USA). Patient 1. A 22-year-old male professional motorbike rider presented with an anterior left hip dislocation that occurred during a race. A CT scan after a closed reduction revealed a large osteochondral impaction fracture/defect that was addressed via partial resurfacing using the HemiCAP System. Patient 2. A 34-year-old male presented with an anterior left hip dislocation after a motor vehicle accident and underwent a closed reduction. CT showed a loose osteochondral fragment, that was fixed back with headless screws, and an adjacent defect was addressed with a HemiCAP implant. Both patients were kept non weight-bearing for two months and had an uneventful recovery. Patient 1 was last reviewed at our institution one month post-operatively with a pain-free hip. His follow-up is being continued interstate and at telephone interview, 18 months after surgery, he had returned to full function and resumed riding on the professional racing circuit. Patient 2, at three-month review, had a pain-free hip with a full range of motion. CT scan showed excellent joint surface congruity at the implant articular surface junction. We report the use of the HemiCAP System as a novel method of treating osteochondral defects, which has never been reported before. There has only been one other reported case of using a HemiCAP in an osteoarthritic femoral head. This is a short follow-up with only two patients treated; however we are encouraged by the results so far, as there are no other satisfactory alternative treatment options

Background. Partial humeral head resurfacing using a stemless implant is a bone-conserving option in treatment of focal chondral defects. We report our experience using the Arthrosurface HemiCAP® device. Methods. This is a retrospective study of patients with focal chondral defects of the humeral head, treated with partial resurfacing arthroplasty, with a minimum follow-up of 2 years. Mean patient age was 45.4 years (range 27–76). Patients were analyzed in 2 groups: those who underwent HemiCAP for an isolated humeral head defect, and those who had HemiCAP combined with biologic resurfacing of concomitant glenoid disease. Results. 39 patients met inclusion criteria, 5 of whom had concomitant biologic glenoid resurfacing. 24 of 34 shoulders (70.6%) with HemiCAP alone demonstrated functional improvement and decreased pain. Mean forward flexion showed some improvement from 131 degrees pre-operatively to 158 degrees post-operatively (p=0.004). Mean Subjective Shoulder Value improved from 35.0% to 83.6% (p< 0.001). ASES score improved from 29.8 to 77.7(p< 0.001). However, follow-up radiographs showed progression of glenoid disease in 20.6%(7 shoulders). 5 shoulders(14.7%) failed and were revised: 3 to total shoulder arthroplasty, 1 to hemiarthroplasty, and 1 patient underwent glenohumeral fusion. 5 (14.7%) had some pain at latest follow-up but were pursuing a course of conservative management. In the group with associated biologic glenoid resurfacing, all 5 patients had ongoing pain and progression of glenohumeral arthritis requiring revision or glenohumeral fusion. Conclusion. While 70% of patients with an isolated humeral head chondral defect had significant improvement in pain and function after HemiCAP, the outcomes were not superior to those published for complete humeral head resurfacing, or for stemmed prostheses. HemiCAP was not successful for patients with concomitant glenoid disease. Results for these patients were inferior to those published for total shoulder arthroplasty, and ultimately all were revised to a stemmed prosthesis or fused

Abstract. Introduction. Active, middle-aged patients with symptomatic cartilage or osteochondral defects can find themselves in a treatment gap when they have failed conservative measures but are not yet eligible for conventional arthroplasty. Data from various cohort studies suggests that focal knee resurfacing implants such as HemiCAP, UniCAP, Episealer or BioBoly are cost-effective solutions to alleviate pain, improve function and delay or eliminate the need for conventional replacement. A systematic review and meta-analysis were conducted in order to(i) evaluate revision rates and implant survival of focal resurfacing; (ii) explore surgical complications; and (iii) evaluate various patient reported clinical outcome measures. Methodology. PubMED, Cochrane Library and Medline databases were searched in February 2022 for prospective and retrospective cohort studies evaluating any of the available implant types. Data on incidence of revision, complications and various patient reported outcome measures was sourced. Results. A total of 24 unique studies were identified with a total of 1465 enrolled patients. A revision rate of 12.97% over a 5.9 year weighted mean follow-up period was observed across all implant types. However, in one series a Kaplan-Meir survival as high as 92.6% at a 10-year follow-up period was noted. A statistically significant improvement was documented across multiple subjective clinical outcomes scores. There was a low reported incidence of post-operative complications such as aseptic loosening or deep wound infection. Conclusions. Focal femoral resurfacing appears to be a viable treatment option for focal symptomatic chondral lesions in patients beyond biological reconstruction, with low revision rates and high patient satisfaction

The aim of this retrospective cohort study was to investigate the reasons for total knee arthroplasty (TKA) revisions at a tertiary hospital over a four-year period. The study aimed to identify the primary causes of TKA revisions and shed light on the implications for patient care and outcomes. The study included 31 patients who underwent revisions after primary knee arthroplasty between January 2017 and December 2020. A retrospective approach was employed, utilizing medical records and radiological findings to identify the reasons for TKA revisions. The study excluded oncology patients to focus on non-oncologic indications for revision surgeries. Patient demographics, including age and gender, were recorded. Data analysis involved categorizing the reasons for revision based on clinical assessments and radiological evidence. Among the 31 patients included in the study, 9 were males and 22 were females. The age of the patients ranged from 43 to 81, with a median age of 65 and an interquartile range of 18.5. The primary reasons for TKA revisions were identified as aseptic loosening (10 cases) and prosthetic joint infection (PJI) (13 cases). Additional reasons included revision from surgitech hemicap (1 case), patella osteoarthritis (1 case), stiffness (2 cases), patella maltracking (2 cases), periprosthetic fracture (1 case), and patella resurfacing (1 case). The findings of this retrospective cohort study highlight aseptic loosening and PJI as the leading causes of TKA revisions in the examined patient population. These results emphasize the importance of optimizing surgical techniques, implant selection, and infection control measures to reduce the incidence of TKA revisions. Future research efforts should focus on preventive strategies to enhance patient outcomes and mitigate the need for revision surgeries in TKA procedures

Background. Focal resurfacing can treat localised articular damage of the knee not appropriate for arthroplasty or biological repair. Independent results on these implants are limited. We previously published early results showing significantly improved Knee Injury & Osteoarthritis Outcome Score (KOOS4) without complication or re-operation, demonstrating this system gives good analgesia and functional improvement in selected patients. We present long-term follow-up of these patients. Methods. We prospectively evaluated medium- to long-term results in patients with localised, full-thickness articular cartilage defects of the knee undergoing HemiCAP resurfacing. All procedures were performed by one consultant surgeon. Post-operative rehabilitation was standardised. Outcome measures were KOOS4 score, visual analogue score (VAS), Kellgren and Lawrence arthritis grade, and re-operation rates. Results. Six patients were evaluated with mean follow-up time of 74 months (range 61–96). Mean age was 44.8 years (range 33–51). One lateral and five medial compartments were resurfaced. Mean pre-operative KOOS4 was 39.1, mean 22-month follow-up KOOS4 improved significantly to 79.6, and mean latest follow-up KOOS4 remained good at 71.3. Mean VAS was 8.8 at latest follow-up. There was no loosening, migration or increase in osteoarthritis grade. One patient underwent revision to unicondylar knee replacement for pain after three years with comparable results at another centre (medial compartment, two year follow-up pre-revision KOOS4 84.6, latest follow-up post-revision KOOS4 73.6, VAS 6). Cause of pain was unclear (heel pain causing prolonged altered weight-bearing or failure of HemiCAP). Conclusion. Our results demonstrate that the use of the joint-preserving HemiCAP system provides good pain relief and functional improvement in both the short and longer-term. Few studies assess functional outcomes of focal resurfacing for localised full thickness articular cartilage defects. Our study assesses both the contemporaneous and time-dependent behaviour of focal resurfacing. We believe this is one of the longest follow-up series to date

Isolated osteochondral defects (OCD) of the femoral head remain a challenging issue for the surgeons when trying to balance between a less invasive procedure and the maximum benefit for the patient. We present our experience of the Hemicap partial hip resurfacing system in 12 patients. In ten patiens the defects were identified arthroscopically. Seven of them had concurrent early degeneration of cartilage (OA, Grade I). Three patients had OCD surrounded by normal cartilage and two patients had avascular necrosis. The mean patient age was 41 years (30 to 63) and mean follow-up 27 months (range 9 to 48). Five patients required a hip resurfacing arthroplasty or total hip replacement at a mean interval of 17 months (12 to 24) due to persistent pain. Three patients required further hip arthroscopy at a mean interval of 36 months (range, 24 to 48). Four patients did not require secondary surgery with mean follow-up 32.7 months (range, 9 to 43). In all hips with revision surgery the components were found to be stable and secure. Partial resurfacing arthroplasty seems to have a tendency towards early failure, especially in OA patients, but more favourable results in AVN patients, and the surgeons should have a cautious approach to this type of arthroplasty

A significant number of patients are affected by localised articular damage that is neither appropriate for traditional arthroplasty, nor for biological repair. A focal resurfacing system utilizing a matched contoured articular prosthetic (HemiCAP. ®. ) has been introduced for the treatment of such cases. Independent results on these implants are limited. We retrospectively evaluated the use of this resurfacing system in 14 patients (13 male, one female), mean age 40.3 years (range 28–49) with focal femoral condyle defects. All procedures were performed by the same consultant orthopaedic surgeon. Clinical evaluation consisted of the Knee injury and Osteoarthritis Outcome Score (KOOS) assessment. Radiographic evaluation was conducted independently to look for signs of any migration of the prosthesis or any radiolucency around it. 10 patients were treated on the medial femoral condyle, two on the lateral, and two received bicondylar implants. Average follow-up was 20 months (range 6–42). All but two patients (no improvement) described a good to excellent response of their symptoms. The KOOS score at follow-up was 79.6, compared to 61.2 prior to treatment (p=0.03). No signs of device migration or radiolucency around the device were observed. None of the patients required re-operation, and there were no cases of superficial/deep infection, thromboembolic events or other significant complication. Our short-term results demonstrate that the use of the joint preserving HemiCAP. ®. system provides good pain relief and functional improvement in such patients

Perthes disease often leaves young adults with hip joint incongruency due to femoral head asphericity, (extra-articular extrusion and superior flattening). This causes femoro-acetabular impingement, a reduced range of movement and early degenerative change. We report a novel method for restoration of femoral head sphericity and femoro-acetabular congruency. Two males (aged 21 and 22 years) presented with groin pain and severe hip stiffness after childhood Perthes disease. Imaging confirmed characteristic saddle shaped deformities of the femoral head, with cartilage loss overlying a central depression in the superior section of the head. A new method of treatment was proposed. Both cases were treated in the same manner. A surgical dislocation was performed with a trochanteric flip osteotomy. The extra-articular bump was removed with osteotomes and a burr to reduce femoro- acetabular impingement. The sphericity of the femoral head was restored using a HemiCap partial re-surfacing (Arthrosurface, MA, USA). The radius of the implant was selected to match that of the acetabulum. Restoration of the height of the flattened portion of the weight-bearing surface of the femoral head reduces abnormal loading of the acetabular articular cartilage by improving congruency of the joint. Both patients recovered without incident and were mobilised with crutches, restricted to touch weight-bearing for six weeks to protect union of the trochanteric osteotomy. At a minimum of three year follow-up both patients had sustained improved range of movement, pain and Oxford hip score. Repeated imaging shows no evidence of joint space narrowing or loosening at this stage. We conclude that this novel treatment functions well in the short term. Further surveillance is on-going to confirm that this treatment results in improved long term durability of the natural hip joint after Perthes disease

Introduction: Perthes disease often leaves young adults with hip joint incongruency due to femoral head asphericity, (an extra-articular extrusion and a superior flattening). This causes femoroacetabular impingement, a reduced range of movement and early degenerative change. We report a novel method for restoration of femoral head sphericity and femoroacetabular congruency. Methods: 2 males (21 & 22 years) presented with groin pain and severe hip stiffness after childhood Perthes disease. Imaging confirmed characteristic saddle shaped deformities of the femoral head, with central depression and overlying cartilage loss. A new method of treatment was proposed. Both cases were treated in the same manner. Results: Using a surgical dislocation with the trochanteric flip osteotomy it was possible to remove the extra-articular bump to reduce femoroacetabular impingement. We found that the sphericity of the femoral head could be restored using a HemiCap partial resurfacing (Arthrosurface, MA, USA). The radius of the implant was selected to match that of the acetabulum. Restoration of the height of the flattened portion of the weight-bearing surface of the femoral head reduces abnormal loading of the acetabular articular cartilage by improving congruency of the joint. At a minimum of 3 year follow up both patients had sustained improved range of movement, pain and Oxford hip score. Repeated imaging shows no evidence of joint space narrowing or loosening at this stage. Conclusion: We conclude that this novel treatment functions well in the short term. Further studies are needed to confirm that after Perthe’s disease this treatment results in improved long term durability of the natural hip joint

Introduction: Hallux Rigidus(HR) is a progressive arthritic process of the first MTP joint that causes pain, stiffness and uncomfortable enlargement of the joint, thus resulting in significant morbidity. Current treatment options include cheilectomy, resection arthroplasty, distal osteotomies (eg Moberg) or arthrodesis (Gold standard). Resurfacing of the metatarsal head, and concurrent joint release allow successful treatment of all stages of Hallux Rigidus, also offering the advantages of maintenance of metatarsal length, and movement. Method: Patients with stage II-IV hallux rigidus, who had failed conservative management, had good bone stock, no previous signs of osteomyelitis and neurovascularly intact status were offered this new procedure. All procedures were performed by the senior author, in a single centre. The HemiCap. ®. MTP prosthesis was implanted using a dorsal approach to the 1st MTPJ. The joint was decompressed and dorsal / lateral bone shaping performed to maximise movement. Pre op and post op scoring at 6 weeks, 3, 6 and 12 months were recorded using AOFAS forefoot, NPS and SF12 scores. Results: 36 First metatarsal head resurfacing procedures were performed on 32 patients. Follow up ranges from 6 weeks to 18 months. Pre op scores averages were AOFAS 22.06 (8–52), SF12 35.55 (14–61.3) and NPS 8.03 (4–10). At 12 months, these average scores had improved significantly to AOFAS 82.57 (55–95) SF12 56.01 (27.5–63.4) and pain scores 0.69 (0–4). There was significant improvement of 60 points on the AOFAS forefoot score, 20 points on the SF12 scoring system, and significant decrease in pain scores of 7.34. Discussion: Initial results of MTPJ resurfacing are encouraging. This technique provides an advantage over cheilectomy which is of limited use in late stage rigidus, and over resection arthroplasty which shortens the 1st MT and risks transfer metatarsalgia. In our practice metatarsal head resurfacing is providing a useful alternative to fusion in active patients who require movement of the MTPJ. Should patients not tolerate the procedure well, the added advantage is easy conversion to the gold standard of fusion. We continue to follow these patients and add further subjects to this study